CN110953542A - Vehicle lamp - Google Patents

Vehicle lamp Download PDF

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Publication number
CN110953542A
CN110953542A CN201910924095.9A CN201910924095A CN110953542A CN 110953542 A CN110953542 A CN 110953542A CN 201910924095 A CN201910924095 A CN 201910924095A CN 110953542 A CN110953542 A CN 110953542A
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CN
China
Prior art keywords
light
phase modulation
modulation element
incident
emitted
Prior art date
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Granted
Application number
CN201910924095.9A
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Chinese (zh)
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CN110953542B (en
Inventor
鬼头壮宜
本桥和也
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koito Manufacturing Co Ltd
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Koito Manufacturing Co Ltd
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Filing date
Publication date
Application filed by Koito Manufacturing Co Ltd filed Critical Koito Manufacturing Co Ltd
Priority to CN202110959766.2A priority Critical patent/CN113606550A/en
Priority to CN202110959769.6A priority patent/CN113606551B/en
Publication of CN110953542A publication Critical patent/CN110953542A/en
Application granted granted Critical
Publication of CN110953542B publication Critical patent/CN110953542B/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
    • B60Q1/00—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor
    • B60Q1/02—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to illuminate the way ahead or to illuminate other areas of way or environments
    • B60Q1/04—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to illuminate the way ahead or to illuminate other areas of way or environments the devices being headlights
    • B60Q1/14—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to illuminate the way ahead or to illuminate other areas of way or environments the devices being headlights having dimming means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
    • F21S41/10—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by the light source
    • F21S41/14—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by the light source characterised by the type of light source
    • F21S41/141—Light emitting diodes [LED]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
    • F21S41/10—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by the light source
    • F21S41/14—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by the light source characterised by the type of light source
    • F21S41/16—Laser light sources
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
    • F21S41/20—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by refractors, transparent cover plates, light guides or filters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
    • F21S41/60—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by a variable light distribution
    • F21S41/63—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by a variable light distribution by acting on refractors, filters or transparent cover plates
    • F21S41/64—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by a variable light distribution by acting on refractors, filters or transparent cover plates by changing their light transmissivity, e.g. by liquid crystal or electrochromic devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S45/00—Arrangements within vehicle lighting devices specially adapted for vehicle exteriors, for purposes other than emission or distribution of light
    • F21S45/10—Protection of lighting devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21W—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO USES OR APPLICATIONS OF LIGHTING DEVICES OR SYSTEMS
    • F21W2102/00—Exterior vehicle lighting devices for illuminating purposes
    • F21W2102/10—Arrangement or contour of the emitted light
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21W—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO USES OR APPLICATIONS OF LIGHTING DEVICES OR SYSTEMS
    • F21W2107/00—Use or application of lighting devices on or in particular types of vehicles
    • F21W2107/10—Use or application of lighting devices on or in particular types of vehicles for land vehicles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/30—Semiconductor lasers

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Chemical & Material Sciences (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Mechanical Engineering (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)
  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
  • Liquid Crystal (AREA)
  • Holo Graphy (AREA)
  • Lighting Device Outwards From Vehicle And Optical Signal (AREA)

Abstract

The invention aims to provide a vehicle lamp which can easily obtain a desired light distribution pattern. A vehicle headlamp (1) as a vehicle lamp comprises: light sources (52R, 52G, 52B) for emitting light of a predetermined wavelength; phase modulation elements (54R, 54G, 54B) for diffracting light emitted from the light sources (52R, 52G, 52B) to form light into a predetermined light distribution pattern; and a movable member (57R, 57G, 57B) that moves the incident point of the light on the phase modulation element (54R, 54G, 54B) relative to the phase modulation element (54R, 54G, 54B). The phase modulation elements (54R, 54G, 54B) are divided into modulation sections (MP) that form light distribution patterns. At least one modulation section (MP) is included within the point of incidence.

Description

Vehicle lamp
Technical Field
The present invention relates to a vehicle lamp.
Background
Various configurations capable of forming a desired light distribution pattern of emitted light are discussed with respect to a vehicle headlamp, which is a vehicle lamp represented by a vehicle headlamp. For example, patent document 1 listed below describes forming a predetermined light distribution pattern using a hologram element, which is one type of phase modulation element.
In a vehicle lamp represented by a headlamp for an automobile, various configurations have been studied in order to make a light distribution pattern of emitted light a predetermined light distribution pattern. For example, in patent document 1 described below, a predetermined light distribution pattern is formed by a hologram element which is a type of phase modulating element.
The vehicle lamp described in patent document 1 includes a hologram element and a light source for irradiating the hologram element with reference light. The hologram element performs calculation so that diffracted light regenerated by irradiation with the reference light forms a predetermined light distribution pattern.
The vehicle lamp described in patent document 1 includes a hologram element and a light source for irradiating the hologram element with reference light. The hologram element is substantially rectangular, and is calculated so that diffracted light reproduced by irradiation with reference light forms a predetermined light distribution pattern.
Various configurations for making emitted light a desired light distribution pattern are discussed with respect to a vehicle headlamp, which is a vehicle lamp represented by a vehicle headlamp. For example, patent document 1 listed below describes forming a predetermined light distribution pattern by a hologram element, which is one type of phase modulation element.
Patent document 1 (Japanese unexamined patent application publication No. 2012-146621)
However, in the phase modulation element described in patent document 1, when light is intensively incident into a specific region, the temperature of the region is high, and the characteristics of the phase modulation element are changed, and there is a possibility that a desired light distribution pattern cannot be formed.
Here, the vehicle vibrates due to the condition of the road surface or the like, and the vehicle lamp also vibrates similarly to the vehicle. Therefore, in the vehicle lamp described in patent document 1, the incident point of the reference light on the hologram element may vibrate with respect to the hologram element due to vibration of the vehicle, and the reference light may not be irradiated to a part of the hologram element. Therefore, in this vehicle lamp, since a predetermined light distribution pattern may not be formed due to vibration of the vehicle, it is desirable that the predetermined light distribution pattern can be formed even if the vibration occurs. In response to this demand, it is considered that the reference light is irradiated to the entire hologram element even if the incident point of the reference light is increased and vibration occurs. However, in this case, since a part of the reference light is not irradiated to the hologram element, energy efficiency is lowered.
In patent document 1, the light source may be, for example, a semiconductor laser. Since the laser light emitted from the semiconductor laser propagates while expanding in a substantially elliptical shape, when the shape of the laser light is not adjusted, the incident point of the laser light is a long substantially elliptical shape that is long in a specific direction. On the other hand, the hologram element is substantially rectangular as described above, and has a shape different from the incident point of the laser beam. Therefore, when the laser beam emitted from the semiconductor laser beam enters the entire hologram element, a part of the laser beam emitted from the semiconductor laser beam does not irradiate the hologram element and lowers the energy efficiency, and therefore there is a demand for suppressing the lowering of the energy efficiency. For this requirement, for example, it is conceivable to adjust the shape of the laser beam so that the shape of the incident point corresponds to the shape of the hologram element. However, in this case, since an optical element for adjusting the shape of the laser beam is used, the vehicle lamp may be increased in size.
In the case of using the vehicle lamp described in patent document 1, it is conceivable to synthesize a desired color using a plurality of semiconductor laser beams emitting laser beams having different wavelengths. However, when a plurality of semiconductor laser beams are used, the distances from the semiconductor laser beams to the phase modulation element for forming a desired light distribution pattern may be different from each other. In general, the diameters of laser beams having different wavelengths emitted from a plurality of semiconductor laser elements tend to be different from each other. In this case, it is considered to align the spot diameter of the laser light incident on the phase modulation element by using a lens or a mask, but this increases the number of components.
Disclosure of Invention
A first object of the present invention is to provide a vehicle lamp that can easily obtain a desired light distribution pattern.
A second object of the present invention is to provide a vehicle lamp capable of forming a predetermined light distribution pattern while suppressing a decrease in energy efficiency.
A third object of the present invention is to provide a vehicle lamp that can suppress a decrease in energy efficiency and an increase in size.
A fourth object of the present invention is to provide a vehicle lamp in which an increase in the number of components can be suppressed.
In order to achieve the first object, a vehicle lamp according to the present invention includes: a light source for emitting light of a predetermined wavelength; a phase modulation element for diffracting the light emitted from the light source to form the light into a predetermined light distribution pattern; a point moving unit that relatively moves an incident point of the light on the phase modulation element with respect to the phase modulation element; the phase modulation element is divided into modulation sections that form the light distribution pattern, and at least one of the modulation sections is included in the incident point.
With this vehicle lamp, since at least one modulation section is included in the incident point, the same light distribution pattern can be formed even when the position of the incident point is shifted. In addition, in this vehicle lamp, since the incident point is relatively moved with respect to the phase modulation element, concentrated incidence of light in a specific region of the phase modulation element can be suppressed, and the specific region can be suppressed from becoming a high temperature. Therefore, the occurrence of a region in which a predetermined light distribution pattern is difficult to form is suppressed, and a desired light distribution pattern is easily obtained.
The distance of relative movement of the incident point is preferably equal to or greater than the radius of the incident point.
The power distribution of light at the incident point is usually different, and a predetermined region such as a central region of the incident point tends to be a peak region of power. When the size of the peak region is considered, if the distance of relative movement of the incident point with respect to the phase modulation element is equal to or greater than the radius of the incident point, the peak regions can be suppressed from overlapping before and after the relative movement, and the specific region of the phase modulation element can be effectively suppressed from becoming high in temperature.
In addition, when the distance by which the incident point moves relative to the other is equal to or greater than the radius of the incident point, the distance is preferably equal to or greater than the diameter of the incident point.
In this case, since the overlap of a part of the incident point after the relative movement and a part of the incident point before the relative movement is suppressed, the temperature increase of the specific region of the phase modulation element can be more effectively suppressed.
In addition, the incidence point may be periodically moved relatively.
In this case, since the incident point periodically moves relatively, it is possible to further suppress the light from being incident on the specific region of the phase modulation element for a long time. Therefore, the temperature increase in the specific region can be effectively suppressed.
The point moving unit may relatively move the incident point in two or more directions.
In this case, the incident point can be relatively moved in a wider range than in the case where the incident point is relatively moved only in one direction. Therefore, the temperature increase of the specific region of the phase modulation element can be effectively suppressed.
The phase modulation element may be an LCOS (Liquid Crystal On Silicon).
The LCOS is a phase modulation element that generates a difference in reflectance in a liquid crystal layer by changing an alignment pattern of liquid crystal molecules. In such an LCOS, when the temperature of a specific region increases, the change in the alignment pattern in the region increases, and therefore it is difficult to obtain a desired light distribution pattern. However, as described above, since the light is suppressed from entering intensively in a specific region, a desired light distribution pattern can be easily obtained even when the phase modulation element is an LCOS.
In addition, the point moving unit may move the light source.
The light source tends to be light compared to the phase modulation element. Therefore, by configuring the point moving unit to move the light source, the incident point can be moved relatively more easily. The point moving unit may be configured to move the phase modulation element as long as the incident point is moved relative to the phase modulation element.
When the light source is moved by the point moving unit as described above, a circuit board for supplying power to the light source is further provided, and the light source may be moved relative to the circuit board.
In this case, only the light source can be moved without moving the circuit board.
In the case where the light source is moved by the point moving portion as described above, the circuit board may include an elastic connection portion electrically connected to the light source.
Thereby, the light source can move relative to the circuit substrate.
In the above vehicle lamp, the phase modulation element may be provided for each of the plurality of light sources.
By providing a plurality of light sources that emit light of different wavelengths, light of a desired color can be generated. In addition, by providing a phase modulation element for each of the plurality of light sources, it is possible to easily adjust the light distribution pattern for each of the light sources.
Further, the phase modulation element may include a plurality of light sources that emit light having different wavelengths from each other, at least two of the plurality of light sources may switch emission of the light at a predetermined cycle, and the plurality of light emitted from the at least two light sources may be incident on a common phase modulation element.
By providing a plurality of light sources that emit light of different wavelengths, light of a desired color can be generated. Further, by making the phase modulation element that receives light from at least two light sources a common phase modulation element, the number of phase modulation elements provided in the vehicle lamp can be reduced, and reduction in the number of components and cost can be achieved.
ADVANTAGEOUS EFFECTS OF INVENTION
With the vehicle lamp of the present invention described above, a vehicle lamp in which a desired light distribution pattern is easily obtained is provided.
In order to achieve the second object, a vehicle lamp according to the present invention includes: a light source that emits light; a phase modulation element having a plurality of modulation units that diffract the light from the light source to form a predetermined light distribution pattern; the width of an incident surface of the phase modulation element on which the light is incident in the vertical direction is larger than the width of the incident surface in the horizontal direction, the size of the incident point of the light on the phase modulation element is a size that can include at least one modulation unit, and at least one of the plurality of modulation units is arranged in the vertical direction.
The amplitude of the vibration of the vehicle in the vertical direction tends to be larger than the amplitude in the horizontal direction, and the vehicle lamp vibrates similarly to the vehicle. Therefore, the incident point of the light on the phase modulation element tends to vibrate in the vertical direction as compared with the horizontal direction. In this vehicle lamp, as described above, the width of the light incident surface of the phase modulation element in the vertical direction is larger than the width of the light incident surface in the horizontal direction. Therefore, even when the incident point vibrates in the vertical direction due to the vibration of the vehicle, the vehicle lamp can suppress a part of the incident point from being exposed from the incident surface of the phase modulation element, and can suppress a decrease in energy efficiency. In this vehicle lamp, as described above, the size of the incident point is a size capable of including at least one modulation unit, and at least a part of the plurality of modulation units are arranged in the vertical direction. Therefore, in this vehicle lamp, even when the incident point vibrates in the vertical direction due to the vibration of the vehicle, the light can be incident on any one of the modulation portions, and therefore a predetermined light distribution pattern can be formed.
The incident point may be in the shape of a long strip that is longer in a specific direction than in other directions, the specific direction being non-parallel to the horizontal direction.
With such a configuration, the width of the incident point in the horizontal direction can be reduced as compared with the case where the specific direction is parallel to the horizontal direction. Therefore, as compared with the case where the specific direction is parallel to the horizontal direction, the width of the phase modulation element in the horizontal direction can be reduced, and the manufacturing cost of the vehicle lamp can be reduced.
Alternatively, the incident point may have a long shape that is longer in a specific direction than in other directions, and the specific direction may not be parallel to the vertical direction.
With this configuration, the width of the incident point in the vertical direction can be reduced as compared with the case where the specific direction is parallel to the vertical direction. Therefore, compared to the case where the specific direction is parallel to the vertical direction, it is possible to suppress a part of the incident point from being exposed from the incident surface of the phase modulation element when the incident point vibrates in the vertical direction due to the vibration of the vehicle.
The plurality of modulation units may be arranged in the vertical direction and the horizontal direction, and the number of modulation units arranged in the vertical direction may be larger than the number of modulation units arranged in the horizontal direction.
With this configuration, it is easier to cause light from the light source to enter any one of the modulation sections when the incident point vibrates in the vertical direction due to vibration of the vehicle, as compared to a case where the number of modulation sections arranged in the vertical direction is smaller than the number of modulation sections arranged in the horizontal direction.
The vehicle lamp may further include a plurality of the light sources, the phase modulation element may be provided for each of the plurality of the light sources, and a width in the vertical direction of the incident point of the phase modulation element having the largest optical path length of the corresponding light source among the plurality of the phase modulation elements may be equal to or smaller than a largest width among widths in the vertical direction of the incident points of the other phase modulation elements.
The amplitude of the vibration of the incident point with respect to the phase modulation element tends to increase as the optical path length between the phase modulation element and the light source increases. In this vehicle lamp, the width of the incident point of the phase modulation element in the vertical direction, at which the amplitude of the vibration of the incident point with respect to the phase modulation element is likely to increase, is equal to or less than the maximum width among the widths of the incident points of the other phase modulation elements in the vertical direction. Therefore, even if the width of the incident surface of the phase modulation element in the vertical direction and the optical path length between the phase modulation element and the light source are not adjusted, it is possible to suppress a part of the incident point of the phase modulation element, which is likely to increase the amplitude of the vibration of the phase modulation element with respect to the incident point, from being exposed from the incident surface of the phase modulation element. Therefore, the degree of freedom in the size of the phase modulation element and the arrangement of the phase modulation element with respect to the light source can be increased.
The light source may be provided in plural, and the phase modulation element may be provided in each of the plural light sources, and at least one of the phase modulation elements may be connected to at least one other of the phase modulation elements and integrally formed with the other phase modulation element.
In this vehicle lamp, since at least two phase modulation elements are integrally formed, the number of components can be reduced.
ADVANTAGEOUS EFFECTS OF INVENTION
With the above-described invention, it is possible to provide a vehicle lamp capable of forming a predetermined light distribution pattern while suppressing a decrease in energy efficiency.
In order to achieve the third object, a vehicle lamp according to the present invention includes: a light source for emitting light; a phase modulation element having at least one modulation section for diffracting the light from the light source to form a predetermined light distribution pattern; an incident surface of the phase modulation element on which the light is incident and an incident point of the light on the phase modulation element are long in a predetermined direction compared with other directions, the incident point has a size capable of including at least one of the modulation units, and a longitudinal direction of the incident surface of the phase modulation element is not perpendicular to a longitudinal direction of the incident point.
In this vehicle lamp, since light from the light source can be incident on at least one of the modulation portions, a predetermined light distribution pattern can be formed by the modulation portion on which the light is incident. In this vehicle lamp, as described above, the longitudinal direction of the incident surface of the phase modulation element is not perpendicular to the longitudinal direction of the incident point. Therefore, compared to the case where the longitudinal direction of the incident surface of the phase modulation element is perpendicular to the longitudinal direction of the incident point, the vehicle lamp can suppress a part of the incident point from being exposed from the phase modulation element without adjusting the shape of the light from the light source. Therefore, the vehicle lamp can be prevented from being increased in size while suppressing a decrease in energy efficiency.
The long side direction of the incident surface of the phase modulation element may be parallel to the long side direction of the incident point.
With this configuration, even if the shape of the laser beam is not adjusted, exposure of a part of the incident point from the phase modulation element can be further suppressed.
The longitudinal direction of the incident surface of the phase modulation element may be a horizontal direction.
The light source may be provided in plural, and the phase modulation element may be provided in each of the plural light sources, and at least one of the phase modulation elements may be connected to at least one other of the phase modulation elements and integrally formed with the other phase modulation element.
In this vehicle lamp, since at least two phase modulation elements are integrally formed, the number of components can be reduced.
The light source may further include a plurality of the light sources, the phase modulation element may be provided for each of the plurality of the light sources, at least two of the phase modulation elements may be arranged adjacent to each other in a specific direction, and a longitudinal direction of each of the incident surfaces of at least two of the phase modulation elements may be parallel to the specific direction.
In this vehicle lamp, as described above, at least two phase modulation elements are arranged adjacent to each other in a specific direction. Therefore, for example, from the viewpoint of simplifying the configuration of the vehicle lamp, a plurality of light sources corresponding to a plurality of phase modulation elements arranged adjacent to each other may be arranged in parallel. In this case, the light from the light source can be made incident on the phase modulation element without using a light guide optical system that guides the incident light to a desired position by reflecting the incident light. In this vehicle lamp, as described above, the longitudinal direction of each of the incident surfaces of the adjacent phase modulation elements is parallel to the specific direction. Therefore, the distance between the centers of the adjacent phase modulation elements can be increased as compared with a case where the longitudinal direction of each of the plurality of phase modulation elements arranged adjacent to each other is perpendicular to the specific direction. Therefore, even when a plurality of light sources are arranged in parallel as described above, the distance between adjacent light sources can be increased as compared with a case where the longitudinal direction of each of the incident surfaces of a plurality of phase modulation elements arranged adjacent to each other is perpendicular to the specific direction. Therefore, compared to a case where the longitudinal direction of each of the incident surfaces of the plurality of phase modulation elements arranged adjacent to each other is perpendicular to the specific direction, the vehicle lamp can further increase the light source, suppress interference between the adjacent light sources, and suppress overheating of the light source due to thermal interference between the adjacent light sources.
ADVANTAGEOUS EFFECTS OF INVENTION
The present invention described above provides a vehicle lamp that can suppress a decrease in energy efficiency and an increase in size.
In order to achieve the fourth object, a vehicle lamp according to the present invention includes: a plurality of light sources that emit light having different wavelengths from each other; at least one phase modulation element for diffracting the light emitted from each of the plurality of light sources to form a predetermined light distribution pattern for each of the plurality of lights; sizes of incident points of the phase modulation elements of at least two of the lights different in wavelength are different from each other.
With this vehicle lamp, it is possible to allow the size of the incident point of light having different wavelengths incident on the phase modulation element to be different. Therefore, it is possible to eliminate the need for providing optical members or the like for adjusting the size of the incident point of light having different wavelengths, and it is possible to suppress an increase in the number of members.
Further, the size of the incident point of each of the plurality of lights may be different.
In this case, the size of the dot diameter can be more effectively adjusted, and an increase in the number of components can be more effectively suppressed.
In addition, at least two of the lights may be incident on the common phase modulation element.
In this way, by making different lights enter a common phase modulation element, the number of phase modulation elements can be reduced.
The phase modulation element may be an LCOS (Liquid Crystal On Silicon).
By using the LCOS as the phase modulation element in this manner, the phase modulation pattern of the phase modulation element can be appropriately changed. In addition, different lights can be incident on a common phase modulation element to form a predetermined light distribution pattern.
In the above-described light source device, the incident point may be increased as the total number of light beams is increased, among at least two light beams having different incident point sizes.
In this case, the energy of each light per unit area of the incident surface of the phase modulation element can be made nearly uniform. Therefore, it is possible to suppress deterioration of a specific phase modulation element earlier than other phase modulation elements.
In the light having the incident point of the at least two light beams having different sizes, the incident point may be smaller as the optical path length to the phase modulation element is longer.
The longer the optical path length to the phase modulation element, the larger the amount of dot movement of the phase modulation element when the light source is moved. Therefore, the longer the optical path length to the phase modulation element, the smaller the spot diameter, and the exposure of the spot diameter from the phase modulation element can be suppressed when the light source is shaken.
In at least two of the lights having the different incident point sizes, the smaller the incident point, the more the light is emitted from the light source.
In this case, even if the phase modulation element that receives light emitted from a larger number of light sources is not larger than the other phase modulation elements, light emitted from the larger number of light sources can be received without leakage.
In addition, when the incident points of the plurality of light beams are different in size, the incident point of the light beam having a longer wavelength may be smaller.
In this case, color bleeding of light color can be suppressed.
ADVANTAGEOUS EFFECTS OF INVENTION
With the vehicle lamp of the present invention as described above, a vehicle lamp in which an increase in the number of components can be suppressed is provided.
Drawings
(first aspect)
Fig. 1 is a longitudinal sectional view schematically showing a vehicle lamp according to a first embodiment of the present invention.
Fig. 2 is an enlarged view of the lamp unit shown in fig. 1.
Fig. 3 is a front view schematically showing a part of the circuit board shown in fig. 2.
Fig. 4 is a front view schematically showing the phase modulation element shown in fig. 2.
Fig. 5 is a view schematically showing a part of a cross section in the thickness direction of the phase modulation element shown in fig. 4.
Fig. 6 is a diagram showing a light distribution pattern of low beams.
Fig. 7 is a view showing a lamp unit of a vehicle lamp according to a second embodiment of the present invention, similarly to fig. 2.
Fig. 8 is a view showing a lamp unit of a vehicle lamp according to a third embodiment of the present invention, similarly to fig. 2.
Fig. 9 is a diagram showing a light distribution pattern of high beam.
(second aspect)
Fig. 10 is a diagram schematically showing a vehicle lamp according to a first embodiment of the present invention.
Fig. 11 is an enlarged view of the optical system unit shown in fig. 10.
Fig. 12 is a front view of the bit modulation element assembly shown in fig. 11.
Fig. 13 is a view schematically showing a part of a cross section in the thickness direction of the phase modulation element assembly shown in fig. 12.
Fig. 14 is a view showing a light distribution pattern.
Fig. 15 is a view showing an optical system unit according to a second embodiment of the present invention, similarly to fig. 11.
Fig. 16 is a front view of a phase modulation element according to a third embodiment of the present invention.
(third aspect)
Fig. 17 is a diagram schematically showing a vehicle lamp according to a first embodiment of the present invention.
Fig. 18 is an enlarged view of the optical system unit shown in fig. 17.
Fig. 19 is a front view of the bit modulation element assembly shown in fig. 18.
Fig. 20 is a view schematically showing a part of a cross section in the thickness direction of the phase modulation element assembly shown in fig. 19.
Fig. 21 is a view showing a light distribution pattern.
Fig. 22 is a diagram schematically showing an optical system unit according to a second embodiment of the present invention.
Fig. 23 is a front view of the phase modulation element assembly shown in fig. 22.
Fig. 24 is a view showing an optical system unit according to a third embodiment of the present invention, similarly to fig. 18.
Fig. 25 is a view showing an optical system unit according to a fourth embodiment of the present invention, similarly to fig. 18.
(fourth aspect)
Fig. 26 is a longitudinal sectional view schematically showing a vehicle lamp according to a first embodiment of the present invention.
Fig. 27 is an enlarged view of a part of the lamp unit shown in fig. 26.
Fig. 28 is a front view schematically showing the phase modulation element shown in fig. 27 together with an incident point of light incident on the phase modulation element.
Fig. 29 is a view schematically showing a part of a cross section in the thickness direction of the phase modulation element shown in fig. 28.
Fig. 30 is a view showing a light distribution pattern of low beams.
Fig. 31 is a view showing a part of a lamp unit of a vehicle lamp according to a second embodiment of the present invention, similarly to fig. 27.
Fig. 32 is a front view schematically showing the phase modulation element shown in fig. 31 together with an incident point of light incident on the phase modulation element.
Fig. 33 is a view showing a part of a lamp unit of a vehicle lamp according to a third embodiment of the present invention, similarly to fig. 27.
Fig. 34 is a front view showing the phase modulation element according to the fourth embodiment of the present invention together with the incident point of light incident on the phase modulation element, from the same perspective as that of fig. 28.
Fig. 35 is a view showing another example using the phase modulation element shown in fig. 31 from the same perspective as that of fig. 32.
Fig. 36 is a diagram showing a light distribution pattern of high beam.
Description of the reference numerals
(first aspect)
1 vehicle headlight (vehicle lamp)
20 luminaire unit
50 optical system unit
52R first light source
52G second light source
52B third light source
54R first phase modulation element
54G second phase modulation element
54B third phase modulation element
54S phase modulation element
55 synthetic optical system
57R, 57G, 57B movable member (dot moving part)
59R, 59G, 59B circuit board
93 elastic connecting part
157R, 157G elastic component
MP modulation part
(second aspect)
1 front shining lamp (vehicle lamp)
10 frame body
20 luminaire unit
50 optical system unit
52R first light source
52G second light source
52B third light source
54 phase modulation element assembly
54R first phase modulation element
54G second phase modulation element
54B third phase modulation element
54S phase modulation element
55 synthetic optical system
155 light guide optical system
EF, EFR, EFG, EFB entrance face
LAR, LAG, LAB Long axis
MPR, MPG, MPB modulation section
SR, SG, SB incident point
Width of H54 phase modulation element in longitudinal direction
Width of WR first phase modulation element in transverse direction
Width of WG second phase modulation element in transverse direction
Lateral width of WB third phase modulation element
Transverse width of WS phase modulation element
(third aspect)
1 front shining lamp (vehicle lamp)
10 frame body
20 luminaire unit
50 optical system unit
52R first light source
52G second light source
52B third light source
54 phase modulation element assembly
54R first phase modulation element
54G second phase modulation element
54B third phase modulation element
54S phase modulation element
55 synthetic optical system
155 light guide optical system
EF, EFR, EFG, EFB entrance face
LAR, LAG, LAB Long axis
MPR, MPG, MPB modulation section
SR, SG, SB incident point
(fourth aspect)
1 vehicle headlight (vehicle lamp)
20 luminaire unit
50 optical system unit
52R first light source
52G second light source
52B third light source
54 phase modulation element assembly
54R first phase modulation element
54G second phase modulation element
54B third phase modulation element
54S phase modulation element
55 synthetic optical system
155 light guide optical system
SR, SG, SB incident point
Detailed Description
(first aspect)
Hereinafter, a mode for implementing the vehicle lamp according to the present invention will be described with reference to the drawings. The following exemplary embodiments are provided to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention can be modified and improved according to the following embodiments without departing from the scope of the invention. In the drawings referred to below, the dimensions of the respective component parts are sometimes changed for easy understanding.
(first embodiment)
Fig. 1 is a diagram showing an example of the vehicle lamp according to the present embodiment, and is a vertical cross-sectional view schematically showing a vertical cross-section of the vehicle lamp. In the present embodiment, the vehicle lamp is a vehicle headlamp 1. As shown in fig. 1, the vehicle headlamp 1 includes a housing 10 and a lamp unit 20 as main components.
The housing 10 has a lamp housing 11, a front cover 12, and a rear cover 13 as main components. The front cover 12 is fixed to the lamp housing 11 so as to close a front opening of the lamp housing 11. An opening smaller than the front is formed in the rear of the lamp housing 11, and the rear cover 13 is fixed to the lamp housing 11 so as to close the opening.
A space formed by the lamp housing 11, the front cover 12 closing the opening in the front of the lamp housing 11, and the rear cover 13 closing the opening in the rear of the lamp housing 11 serves as a lamp chamber R, and the lamp unit 20 is accommodated in the lamp chamber R.
The lamp unit 20 of the present embodiment includes a heat sink 30, a cooling fan 35, a housing 40, and an optical system unit 50 as main components. The lamp unit 20 is fixed to the housing 10 by a structure not shown.
In the present embodiment, the heat sink 30 has a metal bottom plate 31 extending substantially in the front-rear direction, and a plurality of heat radiating fins 32 are provided integrally with the bottom plate 31 on the lower surface side of the bottom plate 31. The cooling fan 35 is disposed with a gap from the heat radiation fins 32, and is fixed to the heat sink 30. The radiator 30 is cooled by an air flow generated by the rotation of the cooling fan 35. Further, a case 40 is disposed on the upper surface of the bottom plate 31 of the heat sink 30.
The case 40 of the present embodiment includes a base 41 made of metal such as aluminum and a cover 42, for example, and the base 41 is fixed to the upper surface of the bottom plate 31 of the heat sink 30. The base 41 is formed in a box shape having an opening extending from the front to the upper side, and the cover 42 is fixed to the base 41 so as to include an opening on the upper side. An opening 40H defined by the distal end of the base 41 and the distal end of the cover 42 is formed in the front portion of the housing 40. An optical system unit 50 is disposed in a space inside the housing 40. The inner walls of the base 41 and the cover 42 are preferably light-absorbing due to black alumite processing or the like. By making the inner walls of the base 41 and the cover 42 light-absorbing, it is possible to suppress accidental reflection or light reflection such as reflection that is applied to the inner wall of the base 41 from being emitted in an unintended direction from the opening 40H.
Fig. 2 is an enlarged view of the optical system unit 50 of the lamp unit 20. As shown in fig. 2, the optical system unit 50 of the present embodiment has a main configuration including a first light source 52R, a second light source 52G, a third light source 52B, a first phase modulation element 54R, a second phase modulation element 54G, a third phase modulation element 54B, and a combining optical system 55. In the present embodiment, the phase modulation elements 54R, 54G, and 54B are reflective phase modulation elements that diffract and emit incident light while reflecting the incident light, and specifically, are reflective LCOS (Liquid Crystal On Silicon).
The first light source 52R is a laser element that emits laser light of a predetermined wavelength, and in the present embodiment, a peak wavelength of power emits red laser light of 638nm, for example, upward. The second light source 52G and the third light source 52B are laser elements that emit laser beams having predetermined wavelengths, respectively, and in the present embodiment, the second light source 52G emits a green laser beam having a peak power wavelength of, for example, 515nm rearward, and the third light source 52B emits a blue laser beam having a peak power wavelength of, for example, 445nm rearward.
The first light source 52R is fixed to a movable portion of the movable member 57R fixed to the base 41. The movable portion of the movable member 57R is connected to a control portion, not shown, and is periodically moved in both the front-rear direction and the depth direction perpendicular to the front-rear direction and the vertical direction by the control of the control portion. The second light source 52G is fixed to the movable portion of the movable member 57G fixed to the base 41. The movable portion of the movable member 57G is connected to a control portion, not shown, and is periodically moved in the vertical direction and the depth direction by the control of the control portion. The third light source 52B is fixed to a movable portion of the movable member 57B fixed to the base 41. The movable portion of the movable member 57B is connected to a control unit, not shown, and is periodically moved in the vertical direction and the depth direction by the control of the control unit.
The first light source 52R is electrically connected to a circuit board 59R fixed to the base 41, and receives power supply via the circuit board 59R. The second light source 52G is electrically connected to a circuit board 59G fixed to the base 41, and receives power supply via the circuit board 59G. The third light source 52B is electrically connected to a circuit board 59B fixed to the base 41, and receives power supply via the circuit board 59B.
The circuit boards 59R, 59G, and 59B each have an elastic connection portion that movably holds the light source. Fig. 3 is a front view schematically showing a part of such a circuit board 59R. Since the circuit boards 59G and 59B have the same configuration as the circuit board 59R, the description of the circuit boards 59G and 59B is omitted.
As shown in fig. 3, a circular hole 90 is formed in the circuit board 59R. A conductive layer 94 is formed on one side and the other side with the circular hole 90 therebetween. These conductive layers 94 are electrically connected via a plate-like conductive member 91. The conductive member 91 has a pair of flat plate portions 92 located outside the circular hole 90 and a pair of elastic connecting portions 93 located inside the circular hole 90. The flat plate portion 92 on one side of the circular hole 90 is fixed to the conductive layer 94 on one side of the circular hole 90. The flat plate portion 92 on the other side of the circular hole 90 is fixed to the conductive layer 94 on the other side of the circular hole 90.
The pair of elastic connection portions 93 is formed in a substantially circular shape as a whole, and the diameter of the circle formed by the pair of elastic connection portions 93 is smaller than the diameter of the terminal of the light source 52R. Therefore, the terminal of the light source 52R electrically connects the light source 52R with the elastic connection portion 93 by fitting inside the circle formed by the elastic connection portion 93, and movably holds the light source 52R by the elastic connection portion 93. With such a configuration, the light source 52R can also move along with the active movement of the movable portion of the movable member 57R.
As shown in fig. 2, the first collimating lens 53R is disposed above the first light source 52R, and collimates the fast axis direction and the slow axis direction of the laser light emitted from the first light source 52R. The second collimator lens 53G is disposed behind the second light source 52G, and collimates the fast axis direction and the slow axis direction of the laser light emitted from the second light source 52G. The third collimator lens 53B is disposed behind the third light source 52B, and collimates the fast axis direction and the slow axis direction of the laser light emitted from the third light source 52B. The collimator lenses 53R, 53G, and 53B are fixed to the housing 40 by a structure not shown.
Further, the fast axis direction and the slow axis direction of the laser beam may be collimated by providing a collimator lens for collimating the fast axis direction of the laser beam and a collimator lens for collimating the slow axis direction of the laser beam, respectively.
The first phase modulation element 54R is disposed above the first collimating lens 53R and fixed to the base 41 by a structure not shown in the drawings. The first phase modulation element 54R is disposed to be inclined at about 45 ° with respect to the front-rear direction and the vertical direction. Therefore, the red laser light emitted from the first collimating lens 53R is incident on the first phase modulation element 54R, diffracted, converted into a direction of about 90 °, and emitted toward the synthesis optical system 55 located in the front.
The second phase modulation element 54G is disposed behind the second collimator lens 53G and fixed to the base 41 by a structure not shown. The second phase modulation element 54G is disposed to be inclined by about 45 ° in the direction opposite to the first phase modulation element 54R with respect to the front-rear direction and the vertical direction. Therefore, the green laser light emitted from the second collimator lens 53G is incident on the second phase modulation element 54G and diffracted, and is converted into a direction of about 90 °, and is emitted toward the synthesis optical system 55 located above.
The third phase modulating element 54B is disposed behind the third collimator lens 53B and is fixed to the base 41 by a structure not shown in the figure. The third phase modulation element 54B is arranged to be inclined by about 45 ° in the direction opposite to the first phase modulation element 54R with respect to the front-rear direction and the up-down direction. Therefore, the blue laser light emitted from the third collimator lens 53B is incident on the third phase modulating element 54B, diffracted, converted into a direction of about 90 °, and emitted to the synthesis optical system 55 located above.
The combining optical system 55 includes a first optical element 55f and a second optical element 55 s. The first optical element 55f is disposed in front of the first phase modulation element 54R and above the second phase modulation element 54G, and is disposed in a state inclined by about 45 ° in the same direction as the first phase modulation element 54R with respect to the front-rear direction and the up-down direction. The first optical element 55f is, for example, a wavelength selective filter in which an oxide film is laminated on a glass substrate, and the type and thickness of the oxide film are adjusted so that light having a wavelength longer than a predetermined wavelength is transmitted and light having a wavelength shorter than the predetermined wavelength is reflected. In the present embodiment, the first optical element 55f transmits red light having a wavelength of 638nm emitted from the first light source 52R, and reflects green light having a wavelength of 515nm emitted from the second light source 52G.
The second optical element 55s is disposed in front of the first optical element 55f and above the third phase modulation element 54B, and is disposed in a state inclined by about 45 ° in the same direction as the first phase modulation element 54R with respect to the front-rear direction and the up-down direction. The second optical element 55s is a wavelength selective filter, similarly to the first optical element. In the present embodiment, the second optical element 55s transmits red light having a wavelength of 638nm emitted from the first light source 52R and green light having a wavelength of 515nm emitted from the second light source 52G, and reflects blue light having a wavelength of 445nm emitted from the third light source 52B.
Next, the configurations of the first phase modulation element 54R, the second phase modulation element 54G, and the third phase modulation element 54B will be described in detail.
In the present embodiment, the phase modulation elements 54R, 54G, and 54B have the same configuration. Therefore, only the first phase modulation element 54R will be described in detail below, and the second phase modulation element 54G and the third phase modulation element 54B will not be described in detail as appropriate.
Fig. 4 is a front view schematically showing the first phase modulation element 54R. As shown in fig. 4, the first phase modulation element 54R is formed in a substantially rectangular shape in front view. The first phase modulation element 54R is divided into a plurality of modulation units MP, and each modulation unit MP includes a plurality of dots arranged in a matrix. The phase modulation element 54R is electrically connected to a drive circuit 60R. The drive circuit 60R includes: a scanning line driving circuit connected to one of the short sides of the phase modulation element 54R, and a data line driving circuit connected to one of the long sides of the phase modulation element 54R. In fig. 4, a circle indicated by a solid line and a circle indicated by a broken line indicate an incident point SR of the red laser beam incident on the incident surface of the first phase modulation element 54R. This point of incidence will be described in detail later.
Fig. 5 is a diagram schematically showing a part of a cross section in the thickness direction of the phase modulation element 54R shown in fig. 4. As shown in fig. 5, the phase modulation element 54R of the present embodiment has a main configuration including a silicon substrate 62, a driving circuit layer 63, a plurality of electrodes 64, a reflective film 65, a liquid crystal layer 66, a transparent electrode 67, and a light-transmissive substrate 68.
The plurality of electrodes 64 are arranged in a matrix on one surface side of the silicon substrate 62 in a one-to-one correspondence with the respective points. The driving circuit layer 63 is a layer in which circuits connected to the scanning line driving circuit and the data line driving circuit of the driving circuit 60R shown in fig. 4 are arranged, and is arranged between the silicon substrate 62 and the plurality of electrodes 64. The light-transmitting substrate 68 is disposed on one side of the silicon substrate 62 so as to face the silicon substrate 62, and is, for example, a glass substrate. The transparent electrode 67 is disposed on the surface of the translucent substrate 68 on the silicon substrate 62 side. The liquid crystal layer 66 includes a plurality of liquid crystal molecules 66a, and is disposed between the plurality of electrodes 64 and the transparent electrode 67. The reflective film 65 is disposed between the plurality of electrodes 64 and the liquid crystal layer 66, and is, for example, a dielectric multilayer film. The red laser beam emitted from the collimator lens 53R enters from the surface of the translucent substrate 68 opposite to the silicon substrate 62 side.
As shown in fig. 5, light RL incident from a surface of the translucent substrate 68 opposite to the silicon substrate 62 side transmits through the transparent electrode 67 and the liquid crystal layer 66, is reflected by the reflective film 65, transmits through the liquid crystal layer 66 and the transparent electrode 67, and is emitted from the translucent substrate 68. When a voltage is applied between a specific electrode 64 and the transparent electrode 67, the alignment of the liquid crystal molecules 66a of the liquid crystal layer 66 located between the electrode 64 and the transparent electrode 67 changes. The change in the alignment of the liquid crystal molecules 66a changes the reflectance of the liquid crystal layer 66 between the electrode 64 and the transparent electrode 67, and changes the optical path length of the light RL transmitted through the liquid crystal layer 66. Therefore, when the light RL is transmitted through the liquid crystal layer 66 and emitted from the liquid crystal layer 66, the phase of the light RL emitted from the liquid crystal layer 66 can be changed from the phase of the light RL incident on the liquid crystal layer 66. As described above, since the plurality of electrodes 64 are arranged for each dot of each modulation section MP, the voltage applied between the electrode 64 and the transparent electrode 67 corresponding to each dot is controlled, the alignment of the liquid crystal molecules 66a is changed, and the amount of change in the phase of light emitted from each dot can be adjusted for each dot. In the present embodiment, the same light distribution pattern is formed from each modulation unit MP by adjusting the reflectance of the liquid crystal layer 66 at each point as described above.
Similarly to the first phase modulation element 54R, the second phase modulation element 54G and the third phase modulation element 54B are each divided into a plurality of modulation units MP, and each modulation unit MP includes a plurality of dots arranged in a matrix. Therefore, by adjusting the reflectance of the liquid crystal layer 66 at each point, the same light distribution pattern is formed from each modulation unit MP.
In the present embodiment, the light distribution pattern formed by the phase modulation elements 54R, 54G, and 54B has the same shape, specifically, the same shape as the light distribution pattern of low beams.
Next, the emission of light from the vehicle headlamp 1 will be described. In the present embodiment, a case where a low beam is emitted from the vehicle headlamp 1 will be described.
When power is supplied from a power supply, not shown, to the first light source 52R via the circuit board 59R, red laser light is generated by the first light source 52R and emitted upward. As described above, the first light source 52R is fixed to the movable member 57R, and the movable member 57R periodically moves in the front-rear direction and the depth direction. Therefore, the red laser beam emitted from the first light source 52R also periodically moves in the front-rear direction and the depth direction. Such red laser light is collimated by the first collimating lens 53R disposed above, and is incident on the phase modulation element 54R.
When power is supplied from a power supply, not shown, to the second light source 52G via the circuit board 59G, green laser light is generated by the second light source 52G and emitted rearward. As described above, the second light source 52G is fixed to the movable member 57G, and the movable member 57G periodically moves in the vertical direction and the depth direction. Therefore, the green laser beam emitted from the second light source 52G also periodically moves in the vertical direction and the depth direction. Such green laser light is collimated by the second collimator lens 53G disposed at the rear, and is incident on the phase modulation element 54G.
When power is supplied from a power supply, not shown, to the third light source 52B via the circuit board 59B, blue laser light is generated by the third light source 52B and emitted rearward. As described above, the third light source 52B is fixed to the movable member 57B, and the movable member 57B periodically moves in the vertical direction and the depth direction. Therefore, the blue laser beam emitted from the third light source 52B also moves regularly in the vertical direction and the depth direction. Such a blue laser beam is collimated by the third collimator lens 53B disposed at the rear, and is incident on the phase modulation element 54B.
The red laser light entering the phase modulation element 54R is reflected by the phase modulation element 54R and emitted forward from the phase modulation element 54R. As described above, the movable member 57R periodically moves in both directions. Therefore, as shown in fig. 4, the incident point SR of the red laser beam periodically moves in two directions along the incident surface of the phase modulation element 54R. In this way, the movable member 57R functions as a point moving unit that moves the incident point SR relative to the phase modulation element 54R. In fig. 4, a circle of a solid line indicates a position of the incident point SR before movement, and a circle of four broken lines indicates a position of the incident point SR after movement.
As shown in fig. 4, at least one modulation unit MP is provided at the incident point SR regardless of the position of the incident point SR on the incident surface of the phase modulation element 54R. Therefore, the light distribution pattern of the red laser beam emitted from the phase modulation element 54R is the same regardless of the relative movement of the incident point SR and the relative movement of the incident point SR. In this way, the red laser beam that becomes the predetermined light distribution pattern is emitted forward from the phase modulation element 54R. Hereinafter, the red laser light emitted from the phase modulation element 54R is the first light DLR. As described above, the shape of the light distribution pattern of the first light DLR is the same as the shape of the light distribution pattern of the low beam. In the present embodiment, the movement distance of the incident point SR on the incident surface of the phase modulation element 54R is equal to or greater than the diameter of the incident point SR. In fig. 4, the incident point is shown by a circle, but the outline of the incident point is not limited to a circle, and may be an ellipse, for example.
The green laser light incident on the phase modulation element 54G is reflected by the phase modulation element 54G and emitted upward from the phase modulation element 54G. As described above, the movable member 57G periodically moves in both directions. Therefore, the incident point of the green laser beam periodically moves in two directions along the incident surface of the phase modulation element 54G. In this way, the movable member 57G functions as a point moving unit that moves the incident point of the green laser beam relative to the phase modulation element 54G.
As with the incident point SR of the red laser beam, at least one modulation unit MP is provided at the incident point of the green laser beam. Therefore, the light distribution pattern of the green laser beam emitted from the phase modulation element 54G is the same regardless of the relative movement of the incident point of the green laser beam before, after, and during the relative movement. Thus, the green light that has become the predetermined light distribution pattern is emitted upward from the phase modulation element 54G. Hereinafter, the green light emitted from the phase modulation element 54G is referred to as second light DLG. As described above, the shape of the light distribution pattern of the second light DLG is the same as the light distribution pattern of the low beam. In the present embodiment, the distance of travel of the incident point of the green laser beam on the incident surface of the phase modulation element 54G is equal to or greater than the diameter of the incident point.
The blue laser light incident on the phase modulation element 54B is reflected by the phase modulation element 54B and emitted upward from the phase modulation element 54B. As described above, the movable member 57B periodically moves in both directions. Therefore, the incident point of the blue laser beam periodically moves in two directions along the incident surface of the phase modulation element 54B. In this way, the movable member 57B functions as a point moving unit that moves the incident point of the blue laser beam relative to the phase modulation element 54G.
Similarly to the incident point SR of the red laser beam, at least one modulation unit MP is provided at the incident point of the blue laser beam. Therefore, the light distribution pattern of the blue laser beam emitted from the phase modulation element 54B is the same regardless of the relative movement of the incident point of the blue laser beam before, after, and during the relative movement. Thus, the blue light that becomes the predetermined light distribution pattern is emitted upward from the phase modulation element 54B. Hereinafter, the blue light emitted from the phase modulation element 54B is referred to as third light DLB. As described above, the shape of the light distribution pattern of the third light DLB is the same as the shape of the light distribution pattern of the low beam. In the present embodiment, the distance of movement of the incident point of the blue laser beam on the incident surface of the phase modulation element 54B is equal to or greater than the diameter of the incident point.
The first optical element 55f of the combining optical system 55 is disposed in front of the first phase modulation element 54R. As described above, the first optical element 55f is configured to transmit red light. Therefore, the first light DLR emitted from the first phase modulation element propagates forward through the first optical element 55 f. Further, a first optical element 55f is disposed above the second phase modulation element 54G. As described above, the first optical element 55f is configured to reflect green light and is inclined by about 45 ° with respect to the front-rear direction and the vertical direction, and therefore the second light DLG emitted from the second phase modulation element 54G is reflected by the first optical element 55f and propagates forward. That is, the first combined light LS1 composed of the first light DLR and the second light DLG propagates toward the second optical element 55 s.
A second optical element 55s of the combining optical system 55 is disposed in front of the first optical element 55 f. As described above, the second optical element 55s is configured to transmit red light and green light. Therefore, the first combined light LS1 is transmitted through the second optical element 55 s. Further, a second optical element 55s is disposed above the third phase modulating element 54B. As described above, the second optical element 55s is configured to reflect blue light and is inclined by about 45 ° with respect to the front-rear direction and the vertical direction, and therefore the third light DLB emitted from the third phase modulating element 54B is reflected by the second optical element 55s and propagates forward. That is, the second combined light LS2 composed of the first light DLR, the second light DLG, and the third light DLB propagates toward the opening 40H of the housing 40 and is emitted from the opening 40H to the outside.
As described above, the lights DLR, DLG, and DLB forming the second combined light each have a light distribution pattern in the shape of a low beam. Therefore, the second combined light LS2 emitted from the opening 40H propagates forward by a predetermined distance, and the lights DLR, DLG, and DLB are superimposed to form the low beam L as white light shown in fig. 6. In fig. 6, the light distribution pattern is indicated by a thick line, and the straight line S indicates a horizontal line. The area LA1 is an area having the highest light intensity, and the light intensity is reduced in the order of the area LA2 and the area LA 3.
With the vehicle headlamp 1 of the present embodiment having the above configuration, the following operational effects can be obtained.
As described above, according to the vehicle headlamp 1 of the present embodiment, since at least one modulator MP is provided at the incident point, the same light distribution pattern can be formed even when the incident point moves. Further, when light is intensively incident on a specific region of the phase modulation element, the region generates heat and becomes high in temperature, and therefore, the characteristics of the phase modulation element in the region change, and it is difficult to form a predetermined light distribution pattern. However, according to the vehicle headlamp 1 of the present embodiment, since the incident point moves relative to the phase modulation element, concentrated incidence of light in a specific region of the phase modulation element can be suppressed, and the temperature of the specific region can be suppressed from increasing. Therefore, the occurrence of a region in which a predetermined light distribution pattern is difficult to form is suppressed, and a desired light distribution pattern is easily obtained.
As described above, in the vehicle headlamp 1 according to the present embodiment, the distance by which the incident point of the red laser beam moves on the incident surface of the phase modulation element 54R is equal to or greater than the diameter of the incident point. Similarly, the distance by which the incident point of the green laser beam moves on the incident surface of the phase modulation element 54G is equal to or greater than the diameter of the incident point. Similarly, the incident point of the blue laser beam moves along the incident surface of the phase modulation element 54B by a distance equal to or greater than the diameter of the incident point. Therefore, as shown in fig. 3, the incident point after the movement can be prevented from overlapping with the incident point before the movement, and the temperature of the specific region of the phase modulation element can be effectively prevented from increasing.
As described above, according to the vehicle headlamp 1 of the present embodiment, since the incident point of the red laser beam, the incident point of the green laser beam, and the incident point of the blue laser beam are periodically moved, it is possible to effectively suppress light from being incident on the specific region of the phase modulation element for a long time, and it is possible to further suppress the specific region of the phase modulation element from being heated to a high temperature. The period for shifting the incident point can be appropriately changed in consideration of the heat resistance of the phase modulation element. For example, the incident point may move in two directions with a period of 1 second, and the period may be 1 minute.
As described above, in the vehicle headlamp 1 according to the present embodiment, since the incident point is moved in two directions by the movable member that is the point moving mechanism, the incident point can be moved in a wider range on the incident surface of the phase modulation element than in the case where the incident point is moved in only one direction. Therefore, the temperature increase in the specific region can be effectively suppressed. Note that the incident point may be moved only in one direction. Further, the incident point may be moved in three or more directions. When the incident point moves in three or more directions, the incident surface of the phase modulation element can move in a wider range than when the incident point moves in two directions. Therefore, the temperature increase in the specific region can be more effectively suppressed.
As described above, in the vehicle headlamp 1 according to the present embodiment, since the light sources 52R, 52G, and 52B are held by the elastic connection portions of the circuit boards 59B, 59G, and 59B, only the light sources 52R, 52G, and 52B can be moved.
As described above, in the vehicle headlamp 1 according to the present embodiment, the phase modulation elements 54R, 54G, and 54B are provided for the light sources 52R, 52G, and 52B, respectively. That is, since the phase modulation elements 54R, 54G, and 54B are provided in one-to-one correspondence with the light sources 52R, 52G, and 52B, the light distribution pattern can be easily adjusted for each light source.
(second embodiment)
Next, a second embodiment of the present invention will be explained. Note that the same or equivalent constituent elements as those of the first embodiment are denoted by the same reference numerals and redundant description thereof is omitted except for the case of special description.
Fig. 7 is a view showing a lamp unit 20 of a vehicle headlamp 1 according to a second embodiment of the present invention, similarly to fig. 2. As shown in fig. 7, the lamp unit 20 of the second embodiment is different from the lamp unit 20 of the first embodiment in that the light sources 52R, 52G, and 52B are attached to the base 41 of the housing 40 via elastic members. Specifically, the first light source 52R is attached to the base 41 via a pair of elastic members 157R, the second light source 52G is attached to the base 41 via a pair of elastic members 157G, and the third light source 52B is attached to the base 41 via a pair of elastic members 157B. The elastic members 157R, 157G, and 157B may be springs, for example.
With this configuration, since the light sources 52R, 52G, and 52B are attached to the base 41 via the elastic members 157R, 157G, and 157B, the light sources 52R, 52G, and 52B passively vibrate in accordance with the vibration during the traveling of the vehicle. Therefore, the incident point moves relative to the phase modulation elements 54R, 54G, and 54B in accordance with the vibration of the light sources 52R, 52G, and 52B. Therefore, as in the first embodiment, the light is prevented from being intensively incident on a specific region of the phase modulation element, and a desired light distribution pattern is easily obtained.
(third embodiment)
Next, a third embodiment of the present invention will be explained. Note that the same or equivalent constituent elements as those of the first embodiment are denoted by the same reference numerals and redundant description thereof is omitted except for the case of special description.
Fig. 8 is a view showing a lamp unit 20 of a vehicle headlamp 1 according to a third embodiment of the present invention, similarly to fig. 2. In fig. 8, a part of the case 40 is omitted for easy understanding. As shown in fig. 8, the lamp unit 20 of the third embodiment differs from the lamp unit 20 of the first and second embodiments in that the optical system unit 50 is configured with three phase modulation elements 54R, 54G, and 54B, in that the number of phase modulation elements of the optical system unit 50 is one. The configuration of the lamp unit 20 according to the third embodiment will be described below.
In the present embodiment, the first light source 52R is arranged to emit red laser light upward, the second light source 52G is arranged to emit green laser light rearward, and the third light source 52B is arranged to emit blue laser light rearward.
The first light source 52R is fixed to a movable portion of the movable member 57R fixed to the base 41. In the present embodiment, the movable portion of the movable member 57R periodically moves in the front-rear direction and the depth direction. Further, the first light source 52R is held by the elastic connection portion of the circuit board 59R, as in the first embodiment. Therefore, the light source 52R can move in the front-rear direction and the depth direction in accordance with the movement of the movable portion of the movable member 57R.
The second light source 52G is fixed to a movable portion of the movable member 57G fixed to the base 41. In the present embodiment, the movable portion of the movable member 57G is periodically moved in the vertical direction and the depth direction. In addition, the second light source 52G is held by the elastic connection portion of the circuit board 59G, as in the first embodiment. Therefore, the light source 52G can move in the vertical direction and the depth direction in accordance with the movement of the movable portion of the movable member 57G.
The third light source 52B is fixed to a movable portion of the movable member 57B fixed to the base 41. In the present embodiment, the movable portion of the movable member 57B periodically moves in the vertical direction and the depth direction. The third light source 52B is held by the elastic connection portion of the circuit board 59B as in the first embodiment. Therefore, the light source 52B can move in the vertical direction and the depth direction in accordance with the movement of the movable portion of the movable member 57B.
The circuit boards 59R, 59G, and 59B are connected to a control unit, not shown. The control unit does not emit light from the light sources 52G and 52B while the light source 52R emits red laser light, does not emit light from the light sources 52R and 52B while the light source 52G emits green laser light, and does not emit light from the light sources 52R and 52G while the light source 52B emits blue laser light. That is, in the present embodiment, the red laser beam from the light source 52R, the green laser beam from the light source 52G, and the blue laser beam from the light source 52B are switched and emitted at predetermined intervals based on the control of the control unit.
In addition, as in the first and second embodiments, the laser beams emitted from the light sources 52R, 52G, and 52B are collimated by the collimator lenses 53R, 53G, and 53B.
A combining optical system 55 is provided above the collimator lens 53R and behind the collimator lenses 53G and 53B. That is, a first optical element 55f is provided above the collimator lens 53R and behind the collimator lens 53G, and a second optical element 55s is provided above the first optical element 55f and behind the collimator lens 53B. These optical elements 55f and 55s are disposed to be inclined by about 45 ° in the front-rear direction and the up-down direction.
A phase modulation element 54S is provided above the second optical element 55S. The phase modulation element 54S is disposed at a position where the red, green, and blue laser beams that have passed through the combining optical system 55 can enter. The phase modulation element 54S of the present embodiment is, for example, a reflective LCOS. The phase modulation element 54S is disposed to be inclined by about 45 ° in the front-rear direction and the up-down direction, and the inclination direction thereof is opposite to the optical elements 55f and 55S.
As in the first and second embodiments, the phase modulation element 54S is divided into a plurality of modulation units, and by adjusting the reflectance of the liquid crystal layer at the dots included in each light distribution pattern, a light distribution pattern having the same shape as the light distribution pattern of low beams can be formed by each modulation unit. In the present embodiment, the entire region of at least one modulation unit is included in each incident point of the red laser light, the green laser light, and the blue laser light.
Next, light emission from the lamp unit 20 of the present embodiment will be described.
As described above, the red laser beam from the light source 52R, the green laser beam from the light source 52G, and the blue laser beam from the light source 52B are emitted while being switched at a predetermined cycle. For example, first, the red laser beam is emitted from the first light source 52R for a predetermined time. In addition, when a plurality of first light sources 52R for emitting red laser beams are provided, the red laser beams are emitted from the plurality of first light sources 52R for a predetermined time. During this period, the laser beams from the light sources 52G and 52B are not emitted. The red laser beam is collimated by the collimator lens 53R, and then enters the phase modulation element 54S through the combining optical system 55. As described above, since the first light source 52R moves in two directions, the incident point of the red laser beam also moves in two directions along the incident surface of the phase modulation element 54S.
As described above, since at least one modulation unit is included in the incident point of the red laser beam, the first light DLR having the light distribution pattern having the same shape as the light distribution pattern of the low beam is emitted forward from the phase modulation element 54S.
When the predetermined time has elapsed, the light from the light source 52R is in a non-emission state, and the green laser light is emitted from the light source 52G for the predetermined time. When a plurality of second light sources 52G for emitting green laser beams are provided, the green laser beams are emitted from the plurality of second light sources 52G for a predetermined time. The green laser beam is collimated by the collimator lens 53G and then enters the phase modulation element 54S through the combining optical system 55. As described above, since the first light source 52R moves in two directions, the incident point of the green laser beam also moves in two directions along the incident surface of the phase modulation element 54S.
As described above, since at least one modulation unit is included in the incident point of the green laser beam, the second light DLG having the light distribution pattern having the same shape as the light distribution pattern of the low beam is emitted forward from the phase modulation element 54S.
Further, when the predetermined time has elapsed, the red laser beam from the light source 52G is in a non-emission state, and the blue laser beam is emitted from the light source 52B for the predetermined time. When a plurality of third light sources 52B for emitting blue laser beams are provided, the blue laser beams are emitted from the plurality of third light sources 52B for a predetermined time. The blue laser beam is collimated by the collimator lens 53B, and then transmitted through the combining optical system 55 to enter the phase modulation element 54S. As described above, since the third light source 52B moves in two directions, the incident point of the blue laser beam also moves in two directions along the incident surface of the phase modulation element 54S.
As described above, since at least one modulation unit is included in the incident point of the blue laser beam, the third light DLB having the light distribution pattern having the same shape as the light distribution pattern of the low beam is emitted forward from the phase modulation element 54S.
The above-described light emission cycle is repeated at a predetermined cycle. When the cycle of the emission cycle is shorter than the time resolution of human vision, an afterimage effect occurs, and a human can recognize that lights of different colors are synthesized and irradiated. Therefore, by making the above-described cycle shorter than the time resolution of a human, the human can recognize that white light in which light DLR that is red light, light DLG that is green light, and light DLB that is blue light are combined is emitted from the lamp unit 20.
Since the time resolution of human vision is approximately 1/30s, the period is preferably 1/30s or less, and more preferably 1/60s or less. Further, the afterimage effect is generated even when the period is larger than 1/30 s. For example, even if the period is 1/15s, the afterimage effect can be produced.
In the vehicle headlamp 1 according to the present embodiment, as in the first and second embodiments, since the incident point moves on the incident surface of the phase modulation element, the light is prevented from being intensively incident on a specific region of the phase modulation element, and a desired light distribution pattern such as a low beam can be easily obtained.
In addition, according to the vehicle headlamp 1 of the present embodiment, unlike the first and second embodiments in which the phase modulation element is provided for each light source, the number of phase modulation elements constituting the optical system unit 50 can be reduced and one phase modulation element can be used, so that the number of components can be reduced and the cost can be reduced.
In the present embodiment, an example in which the light sources 52R, 52G, and 52B switch the emission of light has been described, but at least two of the light sources 52R, 52G, and 52B may switch the emission of light at a predetermined cycle. For example, the third embodiment may be modified such that only the light sources 52R and 52G switch the emission of light at a predetermined cycle. In this modification, the optical system unit 50 can be configured by two phase modulation elements, i.e., a phase modulation element that receives the red laser beam and the green laser beam from the light sources 52R and 52G, and a phase modulation element 54B that receives the blue laser beam from the light source 52B. That is, in this modification, the number of phase modulation elements can be reduced as compared with the first and second embodiments.
As described above, the present invention has been described by taking the first embodiment, the second embodiment, and the third embodiment as examples, but the present invention is not limited to these embodiments.
In the first, second, and third embodiments, the description has been given of an example in which the incident point is moved on the incident surface of the phase modulation element by fixing the phase modulation element to the base and moving the light source. However, the light source may be fixed to the housing 40 and the phase modulation element may be moved relative to the light source. That is, the dot shifting unit may be configured to shift the phase modulation element. Since the light source tends to be lighter than the phase modulation element, the incident point can be more easily moved on the incident surface of the phase modulation element by configuring the point moving unit that moves the light source as in the first, second, and third embodiments.
In the first, second, and third embodiments, the description has been given of an example in which LCOS is used as the phase modulation element, and a diffraction grating may be used as the phase modulation element. The LCOS is a phase modulation element that generates a difference in reflectance in the liquid crystal layer by changing the alignment pattern of the liquid crystal molecules as described above. In such an LCOS, when the temperature of a specific region increases, the change in the alignment pattern of the region increases, and therefore it is likely to be difficult to obtain a desired light distribution pattern. However, according to the first, second, and third embodiments, since concentrated incidence of light in a specific region of the LCOS is suppressed, and an increase in variation of the light distribution pattern is effectively suppressed, it is easy to obtain a desired light distribution pattern. In addition, as the phase modulation element, glv (gratinglight valve) may be used. The GLV is a reflective phase modulation element having a silicon substrate provided with a plurality of reflectors. By using the GLV, different diffraction patterns can be formed by electrically controlling the deflection of the plurality of reflectors. Therefore, for example, the phase modulation element of the third embodiment may use GLV instead of LCOS.
In the first, second, and third embodiments, the description has been given of the example in which the phase modulation element is a reflection type, but the phase modulation element may be a transmission type.
In the first, second, and third embodiments, the example in which the movement distance of the incident point is equal to or greater than the diameter of the incident point is described, and the movement distance of the incident point may be smaller than the diameter of the incident point. For example, the distance by which the incident point is relatively moved may be equal to or greater than the radius of the incident point. The power distribution of light at the incident point is usually different, and for example, a predetermined region such as a central region of the incident point tends to be a peak region of power. When the size of the peak region is considered, if the distance of relative movement of the incident point with respect to the phase modulation element is equal to or greater than the radius of the incident point, the peak regions can be suppressed from overlapping before and after the relative movement, and the specific region of the phase modulation element can be effectively suppressed from becoming high in temperature. In the case where the movement distance of the incident point is smaller than the diameter of the incident point, a region where the incident point before the movement overlaps with the incident point after the movement may be generated, and the temperature rise may increase in this region. Therefore, the moving distance of the incident point is more preferably selected to be equal to or larger than the diameter of the incident point.
In the first, second, and third embodiments, the example in which the incident point is periodically moved has been described, but the incident point may be irregularly moved. When the incident point is irregularly moved, the period during which the incident point stays in the same region increases, and the temperature rise may increase in the region. Therefore, it is preferable that the point of incidence is periodically moved.
In the first, second, and third embodiments, an example in which the vehicle headlamp as a vehicle lamp having only one light source and a phase modulation element that receives light from the light source has three light sources 52R, 52G, and 52B has been described. As in the first, second, and third embodiments, the vehicle lamp has a plurality of light sources that emit light having different wavelengths from each other, and can generate light of a desired color such as white light.
In the first, second, and third embodiments, the low beam L is irradiated to the vehicle headlamp 1 as the vehicle lamp, but the present invention is not particularly limited thereto. For example, the vehicle lamp according to the other embodiment may be configured such that light having a lower intensity than the low beam L is irradiated in a region indicated by a broken line in fig. 6, that is, a region above the region in which the low beam L is irradiated. Such low intensity light is, for example, optical OHS for identification. In this case, it is preferable that the light emitted from each of the phase modulation elements 54R, 54G, and 54B include light OHS for identification. In such an embodiment, it can be understood that a light distribution pattern for night illumination is formed by the low beam L and the marker recognition light OHS. Here, "night" does not simply mean "night" and includes dark places such as tunnels. In addition, the vehicle lamp according to another embodiment may be configured to emit the high beam H shown in fig. 9. In fig. 9, the light distribution pattern of the high beam H is indicated by a thick line, and the straight line S indicates a horizontal line. In the light distribution pattern of the high beam H, the region HA1 is a region having a strong light intensity, and HA2 is a region having a lower light intensity than HA 1. In still another embodiment, the vehicle lamp according to the present invention may be applied to a configuration that constitutes an image. In this case, the direction of light emitted from the vehicle lamp and the mounting position of the vehicle lamp of the vehicle are not particularly limited.
Industrial applicability
The present invention can provide a vehicle lamp that can easily obtain a desired light distribution pattern, and can be used in the field of vehicle lamps such as automobiles.
(second aspect)
Hereinafter, a mode for implementing the vehicle lamp of the present invention is exemplified together with the drawings. The following illustrative embodiments are provided for ease of understanding the present invention and are not intended to be limiting in any way. The present invention can be modified and improved according to the following embodiments without departing from the scope of the present invention.
(first embodiment)
Fig. 10 is a view showing the vehicle lamp according to the present embodiment, and is a view schematically showing a cross section in a vertical direction of the vehicle lamp. The vehicle lamp of the present embodiment is a headlamp 1 for an automobile. The automotive headlamps are respectively arranged in the left and right directions in front of the vehicle, and the left and right headlamps are configured to be substantially symmetrical in the left and right directions. Therefore, in the present embodiment, one headlamp will be described. As shown in fig. 10, the headlamp 1 of the present embodiment has a main configuration including a housing 10 and a lamp unit 20.
The housing 10 has a lamp housing 11, a front cover 12, and a rear cover 13 as main components. The front cover 12 is fixed to the lamp housing 11 so as to close a front opening of the lamp housing 11. An opening smaller than the front is formed in the rear of the lamp housing 11, and the rear cover 13 is fixed to the lamp housing 11 so as to close the opening.
A space formed by the lamp housing 11, the front cover 12 closing the opening in the front of the lamp housing 11, and the rear cover 13 closing the opening in the rear of the lamp housing 11 serves as a lamp chamber R in which the lamp unit 20 is housed.
The lamp unit 20 of the present embodiment has the heat sink 30, the cooling fan 35, the cover 40, and the optical system unit 50 as main components, and is fixed to the housing 10 by a structure not shown in the drawings.
The heat sink 30 has a metal bottom plate 31 extending substantially in the horizontal direction, and a plurality of heat radiating fins 32 are provided integrally with the bottom plate 31 on the lower surface side of the bottom plate 31. The cooling fan 35 is disposed with a gap from the heat radiation fins 32 and fixed to the heat sink 30. The radiator 30 is cooled by an air flow generated by the rotation of the cooling fan 35. Further, a cover 40 is disposed on the upper surface of the bottom plate 31 of the heat sink 30.
The cover 40 is fixed to the bottom plate 31 of the heat sink 30. The cover 40 is substantially rectangular and is made of metal such as aluminum, for example. An optical system unit 50 is housed in a space inside the cover 40. An opening 40H through which light emitted from the optical system unit 50 can pass is formed in the front portion of the cover 40. In order to impart light absorption to the inner walls of the cover 40, it is preferable to perform black alumite processing or the like on these inner walls. By making the inner walls of the cover 40 light-absorbing, even when light is irradiated to these inner walls due to unexpected reflection, or the like, reflection of the irradiated light can be suppressed and the light can be emitted from the opening 40H in an unexpected direction.
Fig. 11 is an enlarged view of the optical system unit shown in fig. 10. In fig. 11, the radiator 30, the cover 40, and the like are omitted for ease of understanding. As shown in fig. 11, the optical system unit 50 of the present embodiment includes a first light-emitting optical system 51R, a second light-emitting optical system 51G, a third light-emitting optical system 51B, a light guide optical system 155, and a phase modulation element assembly 54.
The first light-emitting optical system 51R has a first light source 52R and a first collimating lens 53R. The first light source 52R is a laser element that emits laser light in a predetermined wavelength band, and in the present embodiment, is a semiconductor laser that emits red laser light having a peak wavelength of power of 638nm, for example. The optical system unit 50 includes a circuit board, not shown, on which the first light source 52R is mounted.
The first collimating lens 53R is a lens that collimates the laser light emitted from the first light source 52R in the fast axis direction and the slow axis direction. The red light LR emitted from the first collimating lens 53R is emitted from the first light-emitting optical system 51R. Instead of the first collimating lens 53R, a collimating lens for collimating the laser beam in the fast axis direction and a collimating lens for collimating the laser beam in the slow axis direction may be provided.
The second light emission optical system 51G includes a second light source 52G and a second collimator lens 53G, and the third light emission optical system 51B includes a third light source 52B and a third collimator lens 53B. The light sources 52G and 52B are laser elements that emit laser beams in predetermined wavelength bands, respectively. In the present embodiment, the second light source 52G is a semiconductor laser for emitting a green laser beam having a peak wavelength of power of, for example, 515nm, and the third light source 52B is a semiconductor laser for emitting a blue laser beam having a peak wavelength of power of, for example, 445 nm. Therefore, in the present embodiment, the three light sources 52R, 52G, and 52B emit laser beams in predetermined wavelength bands different from each other. The light sources 52G and 52B are mounted on the circuit board, respectively, in the same manner as the first light source 52R.
The second collimator lens 53G is a lens for collimating the fast axis direction and the slow axis direction of the laser beam emitted from the second light source 52G, and the third collimator lens 53B is a lens for collimating the fast axis direction and the slow axis direction of the laser beam emitted from the third light source 52B. The green light LG emitted from the second collimator lens 53G is emitted from the second light-emitting optical system 51G, and the blue light LB emitted from the third collimator lens 53B is emitted from the third light-emitting optical system 51B. Instead of the collimator lenses 53G and 53B, a collimator lens for collimating the laser beam in the fast axis direction and a collimator lens for collimating the laser beam in the slow axis direction may be provided.
The light guide optical system 155 guides the light LR emitted from the first light emitting optical system 51R, the light LG emitted from the second light emitting optical system 51G, and the light LB emitted from the third light emitting optical system 51B to the phase modulation element assembly 54. The light guide optical system 155 of the present embodiment includes a mirror 155m, a first optical element 155f, and a second optical element 155 s. The reflecting mirror 155m reflects the light LR emitted from the first light-emitting optical system 51R. The first optical element 155f transmits the light LR reflected by the reflecting mirror 155m and reflects the light LG emitted from the second light emission optical system 51G. The second optical element 155s transmits the light LR transmitted through the first optical element 155f and the light LG reflected by the first optical element 155f, and reflects the light LB emitted from the third light-emitting optical system 51B. As the first optical element 155f, the second optical element 155s may be a wavelength selective filter in which an oxide film is laminated on a glass substrate. By controlling the type and thickness of the oxide film, light having a wavelength longer than a predetermined wavelength can be transmitted, and light having a wavelength shorter than the predetermined wavelength can be reflected.
The light guide optical system 155 of the present embodiment does not synthesize these lights LR, LG, and LB, and outputs them in parallel in the left-right direction, and these lights LR, LG, and LB are incident on the phase modulator element assembly 54. In the present embodiment, the lights LR, LG, and LB are arranged in a direction perpendicular to the paper surface of fig. 11. In fig. 11, the light LR, the light LG, and the light LB are shown by solid lines, broken lines, and single-dot chain lines, respectively, and are shown offset from each other.
The phase modulation element assembly 54 diffracts incident light to form the light into a predetermined light distribution pattern. The phase modulation element assembly 54 of the present embodiment is arranged such that the incident surface EF on which light enters is inclined at approximately 45 degrees with respect to the vertical direction, and light LR, LG, and LB emitted from the light guide optical system 155 enters the incident surface EF. The incident surface EF may not be parallel to the horizontal direction, and for example, the phase modulation element assembly 54 may be disposed such that the incident surface EF is substantially parallel to the vertical direction. In the present embodiment, the optical path length from the phase modulation element assembly 54 to the first light source 52R of the first light emission optical system 51R is longer than the optical path length from the phase modulation element assembly 54 to the second light source 52G of the second light emission optical system 51G. The optical path length from the phase modulation element assembly 54 to the second light source 52G of the second light emission optical system 51G is longer than the optical path length from the phase modulation element assembly 54 to the third light source 52B of the third light emission optical system 51B.
As described above, the phase modulation element aggregate 54 includes a plurality of phase modulation elements. Specifically, the phase modulation element aggregate 54 includes: a phase modulation element that diffracts the light LR from the first light-emitting optical system 51R to form the light LR into a predetermined light distribution pattern, a phase modulation element that diffracts the light LG from the second light-emitting optical system 51G to form the light LG into a predetermined light distribution pattern, and a phase modulation element that diffracts the light LB from the third light-emitting optical system 51B to form the light LB into a predetermined light distribution pattern. The three phase modulation elements are arranged in parallel in one direction, and the incident surface EF of the phase modulation element aggregate 54 is formed by the incident surfaces of the light of these phase modulation elements.
In the present embodiment, each of the three phase modulation elements is a reflective phase modulation element that reflects and diffracts incident light to emit the light, and specifically, is a reflective LCOS (Liquid Crystal On Silicon). Therefore, the phase modulation element assembly 54 is diffracted by the phase modulation elements corresponding to the light beams LR, LG, and LB incident on the incident surface EF, and the first light DLR diffracting the red light beam LR, the second light DLG diffracting the green light beam LG, and the third light DLB diffracting the blue light beam LB are emitted from the incident surface EF. The light DLR, DLG, and DLB thus emitted from the phase modulation element assembly 54 is emitted from the optical system unit 50. In fig. 10 and 11, the first light DLR is indicated by a solid line, the second light DLG is indicated by a broken line, and the third light DLB is indicated by a one-dot chain line, and these lights DLR, DLG, and DLB are shown as being shifted from each other.
Next, the structure of the phase modulation element assembly 54 of the present embodiment will be described in detail.
Fig. 12 is a front view of the phase modulation element assembly shown in fig. 11. Fig. 12 is a front view of the phase modulation element assembly 54 as viewed from the incident surface EF side on which light is incident, and fig. 12 schematically shows the phase modulation element assembly 54. The phase modulation element assembly 54 of the present embodiment is formed in a substantially rectangular shape elongated in the horizontal direction in the front view, and the entire region in the front view is the incident surface EF. Therefore, the incident surface EF of the phase modulation element assembly 54 can be understood as being formed in a substantially rectangular shape that is long in the horizontal direction. In the following description, a direction parallel to the horizontal direction in the front view of the phase modulation element assembly 54 is a horizontal direction, and a direction perpendicular to the horizontal direction is a vertical direction. Therefore, the lateral direction is a direction parallel to the horizontal direction, the vertical direction is a direction parallel to a direction projected from the vertical direction to the incident surface EF, and the vertical direction is a direction parallel to the vertical direction in the front view.
The phase modulation element assembly 54 of the present embodiment includes: a first phase modulation element 54R corresponding to the first light emission optical system 51R, a second phase modulation element 54G corresponding to the second light emission optical system 51G, and a third phase modulation element 54B corresponding to the third light emission optical system 51B. The first phase modulation element 54R, the second phase modulation element 54G, and the third phase modulation element 54B are arranged adjacent to each other in the lateral direction, and the first phase modulation element 54R and the third phase modulation element 54B are connected to the second phase modulation element 54G. That is, the phase modulation element assembly has a structure in which the phase modulation elements 54R, 54G, and 54B are integrally formed. A drive circuit 60R is electrically connected to the phase modulation element assembly 54. The drive circuit 60R includes a scanning line drive circuit connected to the lateral side of the phase modulation element assembly 54 and a data line drive circuit connected to one side of the phase modulation element assembly 54 in the longitudinal direction. Electric power is supplied to the phase modulation elements 54R, 54G, and 54B constituting the phase modulation element assembly 54 through the drive circuit 60R.
The width in the longitudinal direction of the first phase modulation element 54R, the width in the longitudinal direction of the second phase modulation element 54G, and the width in the longitudinal direction of the third phase modulation element 54B are the same as the width H54 in the longitudinal direction of the phase modulation element aggregate 54. The width WR of the first phase modulation element 54R in the lateral direction, the width WG of the second phase modulation element 54G in the lateral direction, and the width WB of the third phase modulation element 54B in the lateral direction are smaller than the width H54 of the phase modulation element aggregate 54 in the longitudinal direction. That is, the phase modulation elements 54R, 54G, and 54B are formed in a substantially rectangular shape elongated in the vertical direction, i.e., the vertical direction. As described above, since the entire region of the phase modulation element assembly 54 in the front view is the incident surface EF and the incident surface EF of the phase modulation element assembly 54 is formed by the incident surfaces of the light of the phase modulation elements 54R, 54G, and 54B, the incident surfaces of the light of the phase modulation elements 54R, 54G, and 54B are also formed in a substantially rectangular shape elongated in the vertical direction, that is, the vertical direction. Therefore, the width H54 in the longitudinal direction of the incident surface of the first phase modulation element 54R is larger than the width WR in the lateral direction of the incident surface of the first phase modulation element 54R, the width H54 in the longitudinal direction of the incident surface of the second phase modulation element 54G is larger than the width WG in the lateral direction of the incident surface of the second phase modulation element 54G, and the width H54 in the longitudinal direction of the incident surface of the third phase modulation element 54B is larger than the width WB in the lateral direction of the incident surface of the third phase modulation element 54B. In the present embodiment, it is preferred that,
the width WG of the second phase modulation element 54G in the lateral direction is substantially the same as the width WB of the third phase modulation element 54B in the longitudinal direction, and the width WR of the first phase modulation element 54R in the lateral direction is larger than these widths WG and WB. Therefore, the widths WG and WB of the incident surfaces of the phase modulation elements 54G and 54B in the lateral direction are substantially the same, and the width WR of the incident surface of the first phase modulation element 54R in the lateral direction is larger than these widths WG and WB.
The first phase modulation element 54R has a plurality of modulators MPR arranged in a matrix. The second phase modulation element 54G is provided with a plurality of modulation sections MPG arranged in a matrix, and the third phase modulation element 54B is provided with a plurality of modulation sections MPB arranged in a matrix. In the present embodiment, the modulators MPR, MPG, and MPB are squares having the same size. Therefore, the number of the modulators MPR arranged in the vertical direction is larger than the number of the modulators MPR arranged in the horizontal direction. The number of modulation units MPG arranged in the vertical direction is larger than the number of modulation units MPG arranged in the horizontal direction, and the number of modulation units MPB arranged in the vertical direction is larger than the number of modulation units MPB arranged in the horizontal direction. Each of the modulators MPR, MPG, and MPB includes a plurality of dots arranged in a matrix, and light incident on the modulators MPR, MPG, and MPB is diffracted and emitted.
The red light LR emitted from the light guide optical system 155 is incident on the first phase modulation element 54R, and the first phase modulation element 54R emits the first light DLR diffracted by the light LR. The green light LG emitted from the light guide optical system 155 is incident on the second phase modulation element 54G, and the second phase modulation element 54G emits the second light DLG which diffracts the light LG. The blue light LB emitted from the light guide optical system 155 is incident on the third phase modulation element 54B, and the third phase modulation element 54B emits the third light DLB diffracted by the light LB.
Fig. 12 shows an incident point SR which is a region irradiated with red light LR, an incident point SG which is a region irradiated with green light LG, and an incident point SB which is a region irradiated with blue light LB. In the present embodiment, since the light sources 52R, 52G, and 52B are semiconductor laser light as described above, the laser light emitted from the light sources 52R, 52G, and 52B propagates while spreading in a substantially elliptical shape. The fast axis direction and slow axis direction of the laser beams emitted from the light sources 52R, 52G, and 52B are collimated by the collimating lenses 53R, 53G, and 53B, respectively, but the shapes of the laser beams are not adjusted. Thus, the light LR, LG, and LB having no shape adjusted is emitted from the light emitting optical systems 51R, 51G, and 51B, and is incident on the phase modulation element aggregate 54 via the light guide optical system 155. In the present embodiment, in the light guide optical system 155, since the shapes of the lights LR, LG, and LB are not adjusted, the shapes of the incident points SR, SG, and SB are substantially elliptical.
In the present embodiment, the size of the incident point SR having a substantially elliptical shape is such that at least one modulation unit MPR can be included, and the long axis LAR of the incident point SR is substantially parallel to the lateral direction. In other words, the incident point SR has a substantially elliptical shape elongated in the horizontal direction, and the longitudinal direction of the incident point SR is not parallel to the longitudinal direction. The size of the incident point SG having a substantially elliptical shape is such that at least one modulation unit MPG can be included, and the long axis LAG of the incident point SG is substantially parallel to the longitudinal direction. In other words, incident point SG has a substantially elliptical shape elongated in the longitudinal direction, and the longitudinal direction of incident point SG is not parallel to the lateral direction. The size of the incident point SB having a substantially elliptical shape is such that it can include at least one modulation unit MPB, and the long axis LAB of the incident point SB is substantially parallel to the longitudinal direction. In other words, the incident point SB is a substantially elliptical shape elongated in the longitudinal direction, and the longitudinal direction of the incident point SB is not parallel to the lateral direction.
In the present embodiment, the width SHR in the vertical direction of the incident point SR of the first phase modulation element 54R is smaller than the width SHG in the vertical direction of the incident point SG of the second phase modulation element 54G. The longitudinal width SHG of the incident point SG is substantially the same as the longitudinal width SHB of the incident point SB of the third phase modulation element 54B. Further, the width SHG and the width SHB may be different from each other.
Fig. 13 is a view schematically showing a part of a cross section in the thickness direction of the phase modulation element assembly shown in fig. 12. As shown in fig. 13, the phase modulation element assembly 54 of the present embodiment has a main configuration of a silicon substrate 62, a driving circuit layer 63, a plurality of electrodes 64, a reflective film 65, a liquid crystal layer 66, a transparent electrode 67, and a light-transmissive substrate 68.
The plurality of electrodes 64 are arranged in a matrix on one surface side of the silicon substrate 62 in a one-to-one correspondence with the respective points. The driving circuit layer 63 is a layer in which circuits connected to the scanning line driving circuit and the data line driving circuit of the driving circuit 60R shown in fig. 12 are arranged, and is arranged between the silicon substrate 62 and the plurality of electrodes 64. The transparent substrate 68 is disposed on one side of the silicon substrate 62 so as to face the silicon substrate 62, and is, for example, a glass substrate. The transparent electrode 67 is disposed on the surface of the translucent substrate 68 on the silicon substrate 62 side. The liquid crystal layer 66 has liquid crystal molecules 66a, and is disposed between the plurality of electrodes 64 and the transparent electrode 67. The reflective film 65 is disposed between the plurality of electrodes 64 and the liquid crystal layer 66, and is, for example, a dielectric multilayer film. The light LR emitted from the light guide optical system 155 enters from the incident surface EF on the side opposite to the silicon substrate 62 side of the light transmissive substrate 68.
As shown in fig. 13, light RL incident from an incident surface EF on the side opposite to the silicon substrate 62 side of the transparent substrate 68 passes through the transparent electrode 67 and the liquid crystal layer 66, is reflected by the reflective film 65, passes through the liquid crystal layer 66 and the transparent electrode 67, and is emitted from the transparent substrate 68. When a voltage is applied between a specific electrode 64 and the transparent electrode 67, the alignment of the liquid crystal molecules 66a of the liquid crystal layer 66 located between the electrode 64 and the transparent electrode 67 changes. The change in the alignment of the liquid crystal molecules 66a changes the reflectance of the liquid crystal layer 66 between the electrode 64 and the transparent electrode 67, and changes the optical path length of the light RL transmitted through the liquid crystal layer 66. Therefore, when the light RL is transmitted through the liquid crystal layer 66 and emitted from the liquid crystal layer 66, the phase of the light RL emitted from the liquid crystal layer 66 can be changed according to the phase of the light RL incident on the liquid crystal layer 66. As described above, since the plurality of electrodes 64 are arranged for each point DT of the modulators MPR, MPG, and MPB, the alignment of the liquid crystal molecules 66a can be changed by controlling the voltage applied between the electrode 64 corresponding to each point DT and the transparent electrode 67, and the amount of change in the phase of light emitted from each point DT is adjusted according to each point DT. Since the lights having different phases interfere with each other and are diffracted, the light emitted from the point DT interferes and is diffracted, and the diffracted light is emitted from the phase modulation element assembly 54. Therefore, the phase modulation element assembly 54 can diffract and emit the incident light by adjusting the reflectance of the liquid crystal layer 66 at each point, and can make the light distribution pattern of the emitted light a desired light distribution pattern. The phase modulation element assembly 54 can change the light distribution pattern of the emitted light or change the direction of the emitted light to change the region to which the light is irradiated by changing the reflectance of the liquid crystal layer 66 at each point.
In the present embodiment, the same phase modulation pattern is formed in each of the modulation sections MPR of the first phase modulation element 54R of the phase modulation element assembly 54. The same phase modulation pattern is formed in each modulation section MPG of the second phase modulation element 54G, and the same phase modulation pattern is formed in each modulation section MPB of the third phase modulation element 54B. In the present specification, the phase modulation pattern means a pattern for modulating the phase of incident light. In the present embodiment, the phase modulation pattern is a pattern of the reflectance of the liquid crystal layer 66 at each point DT, and can be understood as a pattern of a voltage applied between the electrode 64 and the transparent electrode 67 corresponding to each point DT. By adjusting the phase modulation pattern, the light distribution pattern of the emitted light can be made to be a desired light distribution pattern. In the present embodiment, the phase modulation patterns of the modulators MPR, MPG, and MPB are different phase modulation patterns from each other.
Specifically, in the present embodiment, the phase modulation patterns of the modulators MPR, MPG, and MPB are phase modulation patterns that diffract the lights LR, LG, and LB, respectively, so that the light obtained by combining the first light DLR emitted from the first phase modulation element 54R, the second light DLG emitted from the second phase modulation element 54G, and the third light DLB emitted from the third phase modulation element 54B becomes a light distribution pattern of low beams. In other words, the phase modulation elements 54R, 54G, and 54B of the phase modulation element assembly 54 diffract the incident light LR, LG, and LB so that the light combined with the light DLR, DLG, and DLB emitted from the phase modulation elements 54R, 54G, and 54B becomes a light distribution pattern of low beam. The light distribution pattern also includes an intensity distribution. Therefore, in the present embodiment, the first light DLR emitted from the first phase modulation element 54R is an intensity distribution that overlaps with the light distribution pattern of the low beam and is based on the intensity distribution of the light distribution pattern of the low beam. The second light DLG emitted from the second phase modulation element 54G is an intensity distribution that overlaps the light distribution pattern of the low beam and is based on the intensity distribution of the light distribution pattern of the low beam. The third light DLB emitted from the third phase modulating element 54B is an intensity distribution that overlaps the light distribution pattern of the low beam and is based on the intensity distribution of the light distribution pattern of the low beam. As described above, the phase modulation elements 54R, 54G, and 54B have the plurality of modulation units MPR, MPG, and MPB that form the same phase modulation patterns, respectively, and diffract the light LR, LG, and LB so that the respective modulation units MPR, MPG, and MPB form the light distribution patterns. It is preferable that the phase modulation elements 54R, 54G, and 54B diffract the incident lights LR, LG, and LB so that the outer shape of the light distribution pattern of the lights DLR, DLG, and DLB emitted from the phase modulation elements 54R, 54G, and 54B matches the outer shape of the light distribution pattern of the low beam. In this way, the first phase modulation element 54R emits light DLR of a red component of the light distribution pattern of low beam, the second phase modulation element 54G emits light DLG of a green component of the light distribution pattern of low beam, and the third phase modulation element 54B emits light DLB of a blue component of the light distribution pattern of low beam.
Next, light emission from the headlamp 1 will be described. Specifically, a case where the low beam is emitted from the headlamp 1 will be described.
By supplying power from a power supply not shown to the light sources 52R, 52G, and 52B, respectively, the first light source 52R emits red laser light, the second light source 52G emits green laser light, and the third light source 52B emits blue laser light. These laser beams are collimated by the collimator lenses 53R, 53G, and 53B and then emitted from the light emitting optical systems 51R, 51G, and 51B. The light LR, LG, and LB emitted from the light emitting optical systems 51R, 51G, and 51B enters the light guide optical system 155.
In the light guide optical system 155, the light LR from the first light emission optical system 51R is reflected by the mirror 155m, passes through the first optical element 155f and the second optical element 155s, and is emitted from the light guide optical system 155. Thus, the light LR emitted from the light guide optical system 155 enters the first phase modulation element 54R of the phase modulation element assembly 54. That is, the light LR is guided to the first phase modulation element 54R of the phase modulation element assembly 54 by the light guide optical system 155. The light LG from the second light-emitting optical system 51G is reflected by the first optical element 155f, passes through the second optical element 155s, and is emitted from the light guide optical system 155. Thus, the light LG emitted from the light guide optical system 155 enters the second phase modulation element 54G of the phase modulation element assembly 54. That is, the light LG is guided to the second phase modulation element 54G of the phase modulation element assembly 54 by the light guide optical system 155. The light LB from the third light-emitting optical system 51B is reflected by the second optical element 155s and exits from the light guide optical system 155. The light LB thus emitted from the light guide optical system 155 enters the third phase modulation element 54B of the phase modulation element assembly 54. That is, the light LB is guided to the third phase modulating element 54B of the phase modulating element assembly 54 by the light guide optical system 155.
The first phase modulation element 54R of the phase modulation element assembly 54 diffracts the light LR incident on the first phase modulation element 54R to emit the first light DLR which is the red component of the light distribution pattern of low beam. The second phase modulation element 54G diffracts the light LG incident on the second phase modulation element 54G and emits the second light DLG, which is the green component of the near-light distribution pattern. The third phase modulating element 54B diffracts the light LB incident on the third phase modulating element 54B to emit third light DLB, which is a blue component of the low beam light distribution pattern. Thus, the lights DLR, DLG, and DLB emitted from the phase modulation element assembly 54 are irradiated to the outside of the headlamp 1 through the front cover 12. At this time, the lights DLR, DLG, and DLB are irradiated at the focal positions at predetermined distances from the vehicle so that the regions irradiated with the lights overlap with each other. The focal position is, for example, a position 25m from the vehicle. Since the light combined by these lights DLR, DLG, and DLB is a light distribution pattern of low beam, the irradiated light becomes low beam. It is preferable that the light DLR, DLG, and DLB have substantially the same outer shape of the light distribution pattern at the focal position.
Fig. 14 is a view showing a light distribution pattern for night illumination, specifically, fig. 14(a) is a view showing a light distribution pattern for low beams, and fig. 14(B) is a view showing a light distribution pattern for high beams. In fig. 14, S denotes a horizontal line, and the light distribution pattern is indicated by a thick line. The region PLA1 in the light distribution pattern PL of low beam, which is a light distribution pattern for night lighting shown in fig. 14(a), is a region with the highest intensity, and the intensity is reduced in the order of the region PLA2 and the region PLA 3. That is, the phase modulation elements 54R, 54G, and 54B of the phase modulation element assembly 54 diffract the synthesized light so that the light forms a light distribution pattern including the intensity distribution of the low beam. In fig. 14, as indicated by a broken line, light having a lower intensity than the low beam may be emitted from the headlamp 1 above the position where the low beam is emitted. The light is an optical OHS for identification. In this case, the light DLR, DLG, and DLB emitted from the respective phase modulation elements 54R, 54G, and 54B of the phase modulation element assembly 54 preferably includes the light OHS for identification. In this case, it can be understood that a light distribution pattern for night illumination is formed by using the low beam and the marker recognition light OHS. The light distribution pattern for night illumination is used not only at night but also in dark places such as tunnels.
As described above, the headlamp 1 of the present embodiment includes: light sources 52R, 52G, and 52B for emitting light; and a phase modulation element aggregate 54 including a first phase modulation element 54R, a second phase modulation element 54G, and a third phase modulation element 54B. The first phase modulation element 54R includes a plurality of modulators MPR that diffract the light LR from the first light source 52R to form a predetermined light distribution pattern. The second phase modulation element 54G has a plurality of modulation portions MPG for diffracting the light LG from the second light source 52G to form a predetermined light distribution pattern. The third phase modulation element 54B has a plurality of modulation sections MPB for diffracting the light LB from the third light source 52B to form a predetermined light distribution pattern. The first phase modulation element 54R has a width H54 in the longitudinal direction of the incident surface larger than a width WR in the lateral direction of the incident surface. The longitudinal width H54 of the incident surface of the second phase modulation element 54G is larger than the lateral width WG of the incident surface, and the longitudinal width H54 of the incident surface of the third phase modulation element 54B is larger than the lateral width WB of the incident surface. The incident point SR of the light LR of the first phase modulation element 54R has a size that can include at least one modulation unit MPR, the incident point SG of the light LG of the second phase modulation element 54G has a size that can include at least one modulation unit MPG, and the incident point SB of the light LB of the third phase modulation element 54B has a size that can include at least one modulation unit MPB. At least a part of the plurality of modulators MPR are vertically aligned, at least a part of the plurality of modulators MPG are vertically aligned, and at least a part of the plurality of modulators MPB are vertically aligned.
The amplitude of the vibration of the vehicle in the vertical direction tends to be larger than the amplitude in the horizontal direction, and the headlamp 1 vibrates similarly to the vehicle. Therefore, the incident points SR, SG, and SB of the light LR, LG, and LB of the phase modulating elements 54R, 54G, and 54B of the phase modulating element aggregate 54 tend to vibrate in the vertical direction with respect to the horizontal direction. That is, the incident points SR, SG, SB tend to vibrate in the vertical direction, which is a direction parallel to the direction projected onto the incident surface EF, in comparison with the horizontal direction, which is a direction parallel to the horizontal direction. In the headlamp 1 of the present embodiment, as described above, the width H54 in the longitudinal direction of the incident surface of each of the phase modulation elements 54R, 54G, and 54B is larger than the widths WR, WG, and WB in the lateral direction of the incident surface. Therefore, even when the incidence points SR, SG, SB vibrate in the longitudinal direction due to the vibration of the vehicle, the headlamp 1 of the present embodiment can suppress a part of the incidence points SR, SG, SB from being exposed from the incidence surfaces of the phase modulation elements 54R, 54G, 54B, and can suppress a decrease in energy efficiency. In the headlamp 1 according to the present embodiment, as described above, the size of each of the incident points SR, SG, and SB is a size that can include at least one of the modulators MPR, MPG, and MPB. At least a part of each of the modulators MPR, MPG, and MPB are arranged in the vertical direction. Therefore, in the headlamp 1 according to the present embodiment, even when the incident points SR, SG, SB move in the longitudinal direction due to vibration of the vehicle, the light LR can be incident on any of the modulators MPR, the light LG can be incident on any of the modulators MPG, and the light LB can be incident on any of the modulators MPG. Therefore, even in this case, the headlamp 1 of the present embodiment can form the light distribution pattern PL of the low beam.
The headlamp 1 of the present embodiment includes a plurality of light sources 52R, 52G, and 52B, and the phase modulation element assembly 54 includes: a first phase modulation element 54R to which the light LR from the first light source 52R is incident, a second phase modulation element 54G to which the light LG from the second light source 52G is incident, and a third phase modulation element 54B to which the light LB from the third light source 52B is incident. That is, the phase modulation elements 54R, 54G, and 54B of the phase modulation element aggregate 54 are provided for the light sources 52R, 52G, and 52B. The optical path length from the phase modulation element assembly 54 to the first light source 52R is longer than the optical path length from the phase modulation element assembly 54 to the second light source 52G, and the optical path length from the phase modulation element assembly 54 to the second light source 52G is longer than the optical path length from the phase modulation element assembly 54 to the third light source 52B. That is, the optical path length from the first phase modulation element 54R to the first light source 52R is longer than the optical path length from the second phase modulation element 54G to the second light source 52G, and the optical path length from the second phase modulation element 54G to the second light source 52G is longer than the optical path length from the third phase modulation element 54B to the third light source 52B. The width SHR in the longitudinal direction of the incident point SR of the first phase modulation element 54R is smaller than the width SHG in the longitudinal direction of the incident point SG of the second phase modulation element 54G and the width SHB in the longitudinal direction of the incident point SB of the third phase modulation element 54B. That is, the width SHR in the vertical direction of the incident point SR of the first phase modulation element 54R having the largest optical path length with respect to the corresponding light source is equal to or less than the largest width among the widths SHG and SHB in the vertical direction of the incident points SG and SB of the other phase modulation elements 54G and 54B.
The amplitude of the vibration of the incident point with respect to the phase modulation element tends to increase as the optical path length between the phase modulation element and the light source increases. In the headlamp 1 of the present embodiment, the width SHR in the longitudinal direction of the incident point SR of the first phase modulation element 54R, at which the amplitude of the vibration of the incident point with respect to the phase modulation element is likely to increase, is smaller than the width in the longitudinal direction of the incident points SG and SB of the other phase modulation elements 54G and 54B. Therefore, even if the widths of the incident surfaces of the phase modulation elements 54R, 54G, and 54B in the longitudinal direction and the optical path lengths of the phase modulation elements 54R, 54G, and 54B and the light sources 52R, 52G, and 52B are not adjusted, it is possible to suppress a part of the incident point SR of the first phase modulation element 54R, which is likely to increase in amplitude of vibration of the phase modulation element with respect to the incident point, from being exposed from the incident surface of the phase modulation element 54R. Therefore, the degree of freedom with respect to the size of the phase modulation elements 54R, 54G, and 54B and the arrangement of the phase modulation elements 54R, 54G, and 54B of the light sources 52R, 52G, and 52B can be increased.
In the headlamp 1 according to the present embodiment, the phase modulation element assembly 54 is configured such that the first phase modulation element 54R and the third phase modulation element 54B are connected to the second phase modulation element 54G, and the phase modulation elements 54R, 54G, and 54B are integrally formed. Therefore, in the headlamp 1 of the present embodiment, the number of components can be reduced as compared with the case where the phase modulation elements 54R, 54G, and 54B are provided separately.
In the headlamp 1 according to the present embodiment, the incident point SR of the first phase modulation element 54R has a substantially elliptical shape elongated in the specific direction, and the specific direction, which is the longitudinal direction of the incident point SR, is not parallel to the longitudinal direction, which is the vertical direction. Therefore, the width SHR in the vertical direction of the incident point SR can be reduced as compared with the case where the specific direction, which is the longitudinal direction of the incident point SR, is parallel to the vertical direction. Therefore, compared to the case where the specific direction, which is the longitudinal direction of the incident point SR, is parallel to the vertical direction, when the incident point SR vibrates in the vertical direction in response to the vibration of the vehicle, it is possible to suppress a part of the incident point SR from being exposed from the incident surface of the phase modulation element 54R. In addition, in order to suppress a part of the incident point SR from being exposed from the incident surface of the first phase modulation element 54R due to vibration of the vehicle, as in the present embodiment, it is preferable that the specific direction which is the longitudinal direction of the incident point SR is parallel to the horizontal direction which is the lateral direction.
In the headlamp 1 of the present embodiment, the incident point SG of the second phase modulation element 54G has a substantially elliptical shape that is long in a specific direction, and the specific direction that is the longitudinal direction of the incident point SG is not parallel to the horizontal direction that is the lateral direction. The incident point SB of the third phase modulating element 54B has a long, substantially elliptical shape that is long in a specific direction, and the specific direction that is the longitudinal direction of the incident point SB is not parallel to the horizontal direction that is the lateral direction. Therefore, as compared with the case where the specific direction, which is the longitudinal direction of the incident points SG and SB, is parallel to the horizontal direction, the width of the phase modulation elements 54G and 54B in the horizontal direction, that is, the lateral direction, can be reduced, and the manufacturing cost of the headlamp 1 can be reduced. In view of reducing the lateral widths WG and WB of the phase modulating elements 54R and 54B, it is preferable that the specific direction, which is the longitudinal direction of the incident points SG and SB, be parallel to the vertical direction, which is the vertical direction, as in the present embodiment.
In the headlamp 1 of the present embodiment, the number of the modulator MPRs arranged in the vertical direction is larger than the number of the modulator MPRs arranged in the horizontal direction. The number of modulation units MPG arranged in the vertical direction is larger than the number of modulation units MPG arranged in the horizontal direction, and the number of modulation units MPB arranged in the vertical direction is larger than the number of modulation units MPB arranged in the horizontal direction.
Therefore, compared to the case where the number of the modulation portions MPR arranged in the vertical direction is smaller than the number of the modulation portions MPR arranged in the horizontal direction, when the incident point SR vibrates in the vertical direction due to the vibration of the vehicle, the light LR from the first light source 52R is easily incident on any one of the modulation portions MPR. In addition, similarly to the modulator MPR, when the incident point SG vibrates in the longitudinal direction due to the vibration of the vehicle, the light LG from the second light source 52G is easily incident on any one of the modulators MPG. In addition, similarly to the modulator MPR, when the incident point SB is vibrated in the longitudinal direction by the vibration of the vehicle, the light LB from the third light source 52B is easily incident on any one of the modulators MPB.
(second embodiment)
Next, a second embodiment of the present invention will be described in detail with reference to fig. 15. Note that, the same or equivalent constituent elements as those of the first embodiment are denoted by the same reference numerals and redundant description thereof is omitted unless otherwise specified.
Fig. 15 is a view showing an optical system unit according to a second embodiment of the present invention, similarly to fig. 11. In fig. 15, the radiator 30, the cover 40, and the like are not described for easy understanding. As shown in fig. 15, the optical system unit 50 of the present embodiment is different from the optical system unit 50 of the first embodiment in that the phase modulation elements 54R, 54G, and 54B are separated from each other and a combining optical system 55 is provided instead of the light guide optical system 155.
The phase modulation elements 54R, 54G, and 54B of the present embodiment are LCOS, similarly to the phase modulation elements 54R, 54G, and 54B of the first embodiment. The phase modulation element 54R is formed in a substantially rectangular shape elongated in the longitudinal direction when viewed from the front side of the incident surface EFR on which light is incident. Therefore, the width of the incident surface EFR of the first phase modulation element 54R in the longitudinal direction is larger than the width of the incident surface EFR of the first phase modulation element 54R in the lateral direction. The first phase modulation element 54R has a plurality of modulation parts MPR arranged in a matrix, and the number of modulation parts MPR arranged in the longitudinal direction of the first phase modulation element 54R is larger than the number of modulation parts MPR arranged in the lateral direction. For example, the light LR from the first light source 52R is provided in the first phase modulation element 54R, and the first phase modulation element 54R emits the first light DLR which diffracts the light LR. In the present embodiment, as in the first embodiment, since the shape of the light LR from the first light source 52R as the semiconductor laser light is not adjusted, the shape of the incident point SR of the first phase modulation element 54R is substantially elliptical. In the present embodiment, as in the first embodiment, the size of the incident point SR having a substantially elliptical shape is such that at least one modulation unit MPR can be included, and the long axis LAR of the incident point SR is substantially parallel to the horizontal direction, i.e., the lateral direction.
The second phase modulation element 54G of the present embodiment is formed in a substantially rectangular shape elongated in the longitudinal direction when viewed from the front side of the incident surface EFG on which light is incident. Therefore, the width of the incident surface EFR of the second phase modulation element 54G in the longitudinal direction is larger than the width of the incident surface EFR of the second phase modulation element 54G in the lateral direction. The second phase modulation element 54G has a plurality of modulation units MPR arranged in a matrix, and the number of modulation units MPG arranged in the vertical direction of the second phase modulation element 54G is larger than the number of modulation units MPG arranged in the horizontal direction. The light LG from the second light source 52G enters the second phase modulation element 54G, and the second phase modulation element 54G emits the second light DLG which diffracts the light LG. In the present embodiment, as in the first embodiment, since the shape of the light LG from the second light source 52G as the semiconductor laser light is not adjusted, the shape of the incident point SG of the second phase modulation element 54G is substantially elliptical. In the present embodiment, as in the first embodiment, the size of the incident point SG having a substantially elliptical shape is such that at least one modulation unit MPG can be included, and the long axis LAG of the incident point SG is substantially parallel to the vertical direction, i.e., the vertical direction.
The third phase modulating element 54B of the present embodiment is formed in a substantially rectangular shape elongated in the longitudinal direction when viewed from the front side of the incident surface EFB on which light is incident. Therefore, the width of the incidence surface EFB of the third phase modulation element 54B in the longitudinal direction is larger than the width of the incidence surface EFB of the third phase modulation element 54B in the lateral direction. The third phase modulation element 54B has a plurality of modulation sections MPB arranged in a matrix, and the number of modulation sections MPB arranged in the vertical direction of the third phase modulation element 54B is larger than the number of modulation sections MPB arranged in the horizontal direction. The light LB from the third light source 52B enters the third phase modulation element 54B, and the third phase modulation element 54B emits third light DLB that diffracts the light LB. In the present embodiment, as in the first embodiment, since the shape of the light LB from the third light source 52B as the semiconductor laser light is not adjusted, the incident point SB of the third phase modulating element 54B has a substantially elliptical shape. In the present embodiment, as in the first embodiment, the size of the incident point SB having a substantially elliptical shape is such that at least one modulation unit MPB can be included, and the major axis LAB of the incident point SB is substantially parallel to the vertical direction, i.e., the longitudinal direction.
The combining optical system 55 of the present embodiment includes a first optical element 55f and a second optical element 55 s. The first optical element 55f is an optical element that combines the first light DLR emitted from the first phase modulation element 54R and the second light DLG emitted from the second phase modulation element 54G. In the present embodiment, the first optical element 55f combines the first light DLR and the second light DLG by transmitting the first light DLR and reflecting the second light DLG. The second optical element 55s is an optical element that combines the first light DLR and the second light DLG combined by the first optical element 55f and the third light DLB emitted from the third phase modulating element 54B. In the present embodiment, the second optical element 55s transmits the first light DLR and the second light DLG combined by the first optical element 55f and reflects the third light DLB, thereby combining the first light DLR, the second light DLG, and the third light DLB. As such a first optical element 55f and a second optical element 55s, a wavelength selective filter in which an oxide film is laminated on a glass substrate can be cited. By controlling the type and thickness of the oxide film, light having a wavelength longer than a predetermined wavelength can be transmitted, and light having a wavelength shorter than the predetermined wavelength can be reflected.
In this way, the first light DLR, the second light DLG, and the third light DLB are combined in the combining optical system 55, and the combined light is emitted from the combining optical system 55. In fig. 15, the first light DLR is indicated by a solid line, the second light DLG is indicated by a broken line, and the third light DLB is indicated by a one-dot chain line, and these lights DLR, DLG, and DLB are shown as being shifted from each other.
In the present embodiment, the phase modulation elements 54R, 54G, and 54B diffract the light LR, LG, and LB from the light sources 52R, 52G, and 52B, respectively, so that the light DLR, DLG, and DLB emitted from the phase modulation elements 54R, 54G, and 54B, respectively, is synthesized by the synthesis optical system 55 and then diffracted into the light distribution pattern PL of low beam. Therefore, the first light DLR, which is the light of the red component of the light distribution pattern PL of low beam, is emitted from the first phase modulation element 54R, the second light DLG, which is the light of the green component of the light distribution pattern PL of low beam, is emitted from the second phase modulation element 54G, and the third light DLB, which is the light of the blue component of the light distribution pattern PL of low beam, is emitted from the third phase modulation element 54B.
In this way, the lights DLR, DLG, and DLB are combined in the combining optical system 55, and the combined white light is emitted from the opening 40H of the cover 40, and the light is emitted from the headlamp 1 through the front cover 12. Since this light has the light distribution pattern PL of the low beam, the irradiated light becomes the low beam.
In the headlamp 1 of the present embodiment, as in the first embodiment, even when the incident points SR, SG, SB vibrate in the longitudinal direction due to the vibration of the vehicle, it is possible to suppress a part of the incident points SR, SG, SB from being exposed from the incident surfaces EFR, EFG, EFB of the phase modulation elements 54R, 54G, 54B, and to suppress a decrease in energy efficiency. In the headlamp 1 of the present embodiment, similarly to the first embodiment, even when the incident points SR, SG, SB vibrate in the longitudinal direction due to vibration of the vehicle, the light LR can be incident on any one of the modulators MPR, the light LG can be incident on any one of the modulators MPG, and the light LB can be incident on any one of the modulators MPB. Therefore, even in such a case, the headlamp 1 of the present embodiment can form the light distribution pattern PL of low beams.
(third embodiment)
Next, a third embodiment of the present invention will be described in detail. Note that the same or equivalent constituent elements as those of the first embodiment are denoted by the same reference numerals and redundant description thereof is omitted unless otherwise specified. The optical system unit 50 of the present embodiment is different from the optical system unit 50 of the first embodiment mainly in that one phase modulation element 54S is provided instead of the phase modulation element assembly 54.
Fig. 16 is a front view of a phase modulation element according to a third embodiment of the present invention. Fig. 16 is a front view of the phase modulation element 54S as viewed from the incident surface side on which light is incident, and in fig. 16, the phase modulation element 54S is schematically shown.
In the present embodiment, the phase modulation element 54S has the same configuration as the phase modulation element 54R of the first embodiment. The phase modulation element 54S of the present embodiment is formed in a substantially rectangular shape elongated in the vertical direction, i.e., the longitudinal direction, when viewed from the front side of the incident surface on which light is incident. Therefore, the width H54 in the longitudinal direction of the incident surface of the phase modulation element 54S is larger than the width WS in the lateral direction of the incident surface of the phase modulation element 54S. The phase modulation element 54S is provided with a plurality of modulation units MPS arranged in a matrix, as in the phase modulation element 54R of the first embodiment. The number of the modulation sections MPS arranged in the longitudinal direction is larger than the number of the modulation sections MPS arranged in the lateral direction. The modulator MPS includes a plurality of dots arranged in a matrix, as in the modulator MPR of the first embodiment, and diffracts and emits light incident on the modulator MPS.
In the present embodiment, the light LR, LG, and LB emitted from the light emitting optical systems 51R, 51G, and 51B is guided to the phase modulation element 54S by the light guide optical system 155 and is incident on the phase modulation element 54S, as in the first embodiment. Therefore, the incidence of these lights LR, LG, and LB on the phase modulator 54S will be described below with reference to fig. 11. In the present embodiment, the power supplied to the light sources 52R, 52G, and 52B is adjusted, laser light is alternately emitted to each of the light sources 52R, 52G, and 52B, and light LR, LG, and LB is alternately emitted to each of the light emitting optical systems 51R, 51G, and 51B. That is, when the first light-emitting optical system 51R emits light LR, the second light-emitting optical system 51G and the third light-emitting optical system 51B do not emit light LG or LB, when the second light-emitting optical system 51G emits light LG, the first light-emitting optical system 51R and the third light-emitting optical system 51B do not emit light LR or LB, and when the third light-emitting optical system 51B emits light LB, the first light-emitting optical system 51R and the second light-emitting optical system 51G do not emit light LR or LG. Emission of laser light from the light sources 52R, 52G, and 52B is sequentially switched, and emission of light LR, LG, and LB from the light emitting optical systems 51R, 51G, and 51B is sequentially switched. Therefore, the lights LR, LG, and LB having different wavelength bands from each other and emitted from the light-emitting optical systems 51R, 51G, and 51B are sequentially incident on the phase modulator 54S. The phase modulation element 54S sequentially emits the light DLR, DLG, and DLB obtained by diffracting the incident light LR, LG, and LB. In the present embodiment, similarly to the first embodiment, the optical path length from the phase modulation element 54S to the first light source 52R is longer than the optical path length from the phase modulation element 54S to the second light source 52G, and the optical path length from the phase modulation element 54S to the second light source 52G is longer than the optical path length from the phase modulation element 54S to the third light source 52B.
Fig. 16 shows an incident point SR which is a region irradiated with red light LR, an incident point SG which is a region irradiated with green light LG, and an incident point SB which is a region irradiated with blue light LB. In fig. 16, the incident point SR is indicated by a solid line, the incident point SG is indicated by a broken line, and the incident point SB is indicated by a one-dot chain line. In the present embodiment, as in the first embodiment, since the shapes of the lights LR, LG, and LB from the light sources 52R, 52G, and 52B as the semiconductor laser light are not adjusted, the incident points SR, SG, and SB of the lights LR, LG, and LB of the phase modulator 54S have a substantially elliptical shape. In the present embodiment, the sizes of the incident points SR, SG, and SB having the substantially elliptical shapes are set to sizes that can include at least one modulation unit MPS. Further, the incident points SR, SG, SB coincide with each other.
In the present embodiment, the incident point SR has a substantially elliptical shape elongated in the horizontal direction, and the longitudinal direction of the incident point SR is not parallel to the longitudinal direction. The incident point SG has a substantially elliptical shape elongated in the longitudinal direction, and the longitudinal direction of the incident point SG is not parallel to the lateral direction. Further, the incident point SB is formed in a substantially elliptical shape elongated in the longitudinal direction, and the longitudinal direction of the incident point SB is not parallel to the lateral direction. In the present embodiment, the width of incident point SR in the longitudinal direction is smaller than the width of incident point SG in the longitudinal direction, and the width of incident point SG in the longitudinal direction is substantially the same as the width of incident point SB in the longitudinal direction.
Next, the light emitted from the phase modulation element 54S of the present embodiment will be described. Specifically, a case where the headlamp 1 emits light of the light distribution pattern PL of low beam will be described as an example.
In the present embodiment, the phase modulation element 54S changes the phase modulation pattern in synchronization with the switching of the emission of the laser light from each of the light sources 52R, 52G, and 52B. Specifically, when the light LR from the light source 52R enters the phase modulation element 54S, the phase modulation pattern corresponding to the light source 52R, that is, the phase modulation pattern of the light of the red component of the light distribution pattern of the low beam is formed by the first light DLR emitted from the phase modulation element 54S. Therefore, when the light LR from the light source 52R enters, the phase modulation element 54S emits the first light DLR which is the light of the red component of the light distribution pattern of the low beam. When the light LG from the light source 52G enters, the phase modulation element 54S forms a phase modulation pattern corresponding to the light source 52G, that is, the phase modulation pattern of the green component light of the light distribution pattern of the low beam is formed by the second light DLG emitted from the phase modulation element 54S. Therefore, when the light LG from the light source 52G enters, the phase modulation element 54S emits the second light DLG, which is the green component of the light distribution pattern of the low beam. When the light LB from the light source 52B enters the phase modulation element 54S, the phase modulation pattern corresponding to the light source 52B, that is, the phase modulation pattern of the blue component light of the light distribution pattern of the low beam is formed by the third light DLB emitted from the phase modulation element 54S. Therefore, when the light LB from the light source 52B enters, the phase modulation element 54S emits the third light DLB, which is the blue component of the light distribution pattern of the low beam.
That is, the phase modulation element 54S changes the phase modulation pattern in accordance with the wavelength band of the light LR, LG, and LB thus incident, and sequentially emits the first light DLR, which is the light of the red component of the low beam, the second light DLG, which is the light of the green component of the low beam, and the third light DLB, which is the light of the blue component of the low beam. These lights DLR, DLG, and DLB are emitted from the opening 40H of the cover 40, and are sequentially irradiated to the outside of the headlamp 1 through the front cover 12. At this time, the first light DLR, the second light DLG, and the third light DLB are irradiated at the focal positions at predetermined distances from the vehicle so that the regions irradiated with the light overlap each other. The focal position is, for example, a position 25m from the vehicle. It is preferable that the first light DLR, the second light DLG, and the third light DLB are irradiated so that the outlines of the regions irradiated with the respective lights DLR, DLG, and DLB at the focal position substantially match each other. In the present embodiment, since the emission time lengths of the laser beams emitted from the light sources 52R, 52G, and 52B are substantially the same, the emission time lengths of the light beams DLR, DLG, and DLB are also substantially the same.
In addition, when lights having different colors are repeatedly irradiated at a cycle shorter than the time resolution of human vision, a human can recognize that the lights having the different colors are irradiated by synthesizing the lights due to an afterimage phenomenon. In the present embodiment, when the time for emitting the laser light again from the first light source 52R after emitting the laser light from the first light source 52R is shorter than the time resolution for human vision, the light DLR, DLG, and DLB emitted from the phase modulation element 54S is repeatedly irradiated with light at a cycle shorter than the time resolution for human vision, and the red light DLR, the green light DLG, and the blue light DLB are combined by the afterimage phenomenon. As described above, the emission time lengths of the light DLR, DLG, and DLB are substantially the same, and the intensities of the laser beams emitted from the light sources 52R, 52G, and 52B are predetermined intensities as in the first embodiment. Therefore, the color of the light synthesized by the afterimage phenomenon is the same white as the light after the light DLR, DLG, DLB synthesis of the first embodiment. Further, since the light distribution pattern of the light after the light DLR, DLG, and DLB is synthesized is the light distribution pattern PL of the low beam, the light distribution pattern of the light after the light DLR, DLG, and DLB is synthesized by the afterimage phenomenon also becomes the light distribution pattern PL of the low beam. Thus, the light of the light distribution pattern PL of the low beam is emitted from the headlamp 1.
The cycle of repeatedly emitting laser light from the light sources 52R, 52G, and 52B is preferably 1/15s or less from the viewpoint of suppressing the perception of flicker of light synthesized by the afterimage phenomenon. The temporal resolution of human vision is approximately 1/30 s. In a vehicle lamp, when the light emission cycle is about 2 times, the flicker of the sensed light can be suppressed. When the period is 1/30s or less, the time resolution of human vision is substantially exceeded. Therefore, the flicker of the sensed light can be further suppressed. In addition, from the viewpoint of further suppressing the flicker of the sensed light, the period is preferably 1/60s or less.
In the present embodiment, as described above, the width H54 in the longitudinal direction of the incident surface of the phase modulation element 54S is larger than the width WS in the lateral direction of the incident surface. The incident points SR, SG, SB of the phase modulation element 54S have a size that can include at least one modulation unit MPS, and at least some of the plurality of modulation units MPS are arranged in the longitudinal direction. Therefore, in the headlamp 1 of the present embodiment, as in the first embodiment, even when the incident points SR, SG, SB move in the longitudinal direction due to vibration of the vehicle, the light distribution pattern PL of the low beam can be formed.
In the present embodiment, as described above, the width in the vertical direction of the incident point SR having the largest optical path length of the corresponding light source is equal to or less than the largest width in the vertical direction of the other incident points SG and SB. Therefore, in the headlamp 1 of the present embodiment, similarly to the first embodiment, without adjusting the width H54 in the longitudinal direction of the incident surface of the phase modulation element 54S and the optical path lengths of the phase modulation element 54S and the light sources 52R, 52G, and 52B, it is possible to suppress a part of the incident point SR, which is likely to increase in amplitude of vibration of the phase modulation element 54S, from being exposed from the incident surface of the phase modulation element 54S.
In the present embodiment, the incident point SR has a substantially elliptical shape having a long length in a specific direction, and the specific direction which is the longitudinal direction of the incident point SR is not parallel to the vertical direction which is the vertical direction. Therefore, in the headlamp 1 of the present embodiment, as in the first embodiment, when the incident point SR vibrates in the vertical direction due to the vibration of the vehicle, it is possible to suppress a part of the incident point SR from being exposed from the incident surface of the phase modulation element 54R, as compared with the case where the specific direction, which is the longitudinal direction of the incident point SR, is parallel to the vertical direction.
In the present embodiment, the number of the modulation sections MPS arranged in the longitudinal direction is larger than the number of the modulation sections MPS arranged in the lateral direction. Therefore, as in the first embodiment, when the incident points SR, SG, SB vibrate in the longitudinal direction due to the vibration of the vehicle, the lights LR, LG, LB from the light sources 52R, 52G, 52B are more likely to be incident on any of the modulation sections MPG, as compared with the case where the number of the modulation sections MPS arranged in the longitudinal direction is smaller than the number of the modulation sections MPS arranged in the lateral direction.
In the headlamp 1 according to the present embodiment, since the phase modulation elements diffracted by the light LR, LG, and LB from the three light sources 52R, 52G, and 52B are common phase modulation elements, the number of components can be reduced, and the size can be reduced.
The present invention has been described above by taking the above embodiments as examples, but the present invention is not limited thereto.
The vehicle lamp of the invention comprises: the phase modulation element includes a light source and a plurality of modulation units for diffracting light from the light source to form a predetermined light distribution pattern, a width of an incident surface of the phase modulation element in a longitudinal direction on which the light is incident is larger than a width of the incident surface in a transverse direction, and a size of an incident point of the light on the phase modulation element is a size capable of including at least one modulation unit. In the vehicle lamp having such a configuration, even when the incident point is vibrated in the longitudinal direction by the vibration of the vehicle, a part of the incident point can be suppressed from being exposed from the incident surface of the phase modulation element, and the energy efficiency can be suppressed from being lowered. In addition, even when the incident point is vibrated in the longitudinal direction by the vibration of the vehicle, the light can be incident on any of the modulation sections, and therefore, a predetermined light distribution pattern can be formed.
In the above embodiment, the headlight 1 serving as the vehicle lamp irradiates low beams, but the present invention is not particularly limited thereto. For example, the vehicle lamp may emit high beam or light constituting an image. When the vehicle lamp is irradiated with high beam, light of a light distribution pattern PH of high beam, which is a light distribution pattern for night illumination shown in fig. 14(B), is irradiated. In the distribution pattern PH of high beam in fig. 14(B), the region PHA1 is the region with the highest intensity, and the region PHA2 is the region with lower intensity than the region PHA 1. That is, the phase modulation elements 54R, 54G, and 54B of the phase modulation element assembly 54 according to the first embodiment diffract light so that the combined light forms a light distribution pattern including the intensity distribution of the high beam. The phase modulation elements 54R, 54G, and 54B according to the second embodiment diffract light so that the combined light forms a light distribution pattern including the intensity distribution of the high beam. The phase modulation element 54S according to the third embodiment diffracts light so that the light synthesized by the afterimage phenomenon forms a light distribution pattern including the intensity distribution of the high beam. In addition, when the vehicle lamp irradiates light constituting an image, the direction of light emitted from the vehicle lamp and the position where the vehicle lamp is mounted on the vehicle are not particularly limited.
In the above embodiment, the phase modulation elements 54R, 54G, 54B, and 54S are reflective phase modulation elements. However, as the phase modulation element, for example, an lcd (liquid crystal display) which is a liquid crystal panel, a glv (grating Light valve) in which a plurality of reflectors are formed on a silicon substrate, a diffraction grating, or the like may be used. The LCD is a transmissive phase modulation element. In this LCD, similarly to the LCOS which is the reflective liquid crystal panel, the voltage applied between the pair of electrodes sandwiching the liquid crystal layer is controlled at each point, and the amount of change in the phase of light emitted from each point is adjusted, whereby the light distribution pattern of the emitted light can be made to be a desired light distribution pattern. Further, the pair of electrodes is not a transparent electrode. GLV is a reflective phase modulation element. The GLV diffracts incident light to emit the light and makes a light distribution pattern of the emitted light a desired light distribution pattern by electrically controlling the deflection of the reflector.
In the first embodiment, the first phase modulation element 54R, the second phase modulation element 54G, and the third phase modulation element 54B of the phase modulation element assembly 54 are arranged adjacent to each other in the lateral direction. However, the phase modulation elements 54R, 54G, and 54B may be arranged in the longitudinal direction, or may be arranged in the longitudinal direction and the lateral direction.
In the first and third embodiments, the light guide optical system 155 includes the reflecting mirror 155m, the first optical element 155f, and the second optical element 155 s. However, the light guide optical system 155 is not limited to the configurations of the first and third embodiments described above, as long as it guides the light LR, LG, and LB emitted from the light emitting optical systems 51R, 51G, and 51B to the phase modulation element aggregate 54 and the phase modulation element 54S. For example, the light guide optical system 155 may not have the reflecting mirror 155 m. In this case, the light LR emitted from the first light-emitting optical system 51R enters the first optical element 155 f. In the first and third embodiments, band pass filters that transmit light in a predetermined wavelength range and reflect light in other wavelength ranges may be used for the first and second optical elements 155f and 155 s.
In the first and third embodiments, the optical system unit 50 includes the light guide optical system 155 for guiding the light LR, LG, and LB emitted from the light emitting optical systems 51R, 51G, and 51B to the phase modulation element aggregate 54 and the phase modulation element 54S. However, the optical system unit 50 may not have the light guide optical system 155. In this case, the light emitting optical systems 51R, 51G, and 51B are arranged so that the light LR, LG, and LB enters the phase modulation element aggregate 54 and the phase modulation element 54S.
In the second embodiment, the first optical element 55f transmits the first light DLR and reflects the second light DLG to combine the first light DLR and the second light DLG, and the second optical element 55s transmits the first light DLR and the second light DLG combined by the first optical element 55f and reflects the third light DLB to combine the first light DLR, the second light DLG, and the third light DLB. However, for example, the third light DLB and the second light DLG may be combined in the first optical element 55f, and the third light DLB and the second light DLG combined in the first optical element 55f may be combined with the first light DLR in the second optical element 55 s. In this case, in the second embodiment, the positions of the first light source 52R, the first collimating lens 53R, the first phase modulation element 54R, the third light source 52B, the third collimating lens 53B, and the third phase modulation element 54B may be replaced. In the second embodiment, a band-pass filter that transmits light in a predetermined wavelength band and reflects light in other wavelength bands may be used for the first optical element 55f and the second optical element 55 s. In the second embodiment, the combining optical system 55 may combine the lights DLR, DLG, and DLB emitted from the phase modulation elements 54R, 54G, and 54B, and is not limited to the configuration of the second embodiment and the configuration described above.
In the second embodiment, the optical system unit 50 includes the combining optical system 55 that combines the first light DLR, the second light DLG, and the third light DLB. However, the optical system unit 50 may not have the synthesizing optical system 55. In this case, as in the first embodiment, the phase modulation elements 54R, 54G, and 54B diffract the incident light LR, LG, and LB so that the light DLR, DLG, and DLB emitted from the phase modulation elements 54R, 54G, and 54B are combined.
In the first embodiment, the optical system unit 50 does not include a synthesis optical system for synthesizing the first light DLR, the second light DLG, and the third light DLB. However, the optical system unit 50 of the first embodiment may have a combining optical system, as in the second embodiment.
In the second embodiment, the optical system unit 50 does not include a light guide optical system for guiding the light LR, LG, and LB emitted from the light emitting optical systems 51R, 51G, and 51B to the phase modulation elements 54R, 54G, and 54B. However, the optical system unit 50 of the second embodiment may have a light guide optical system as in the first embodiment.
In addition, in the above embodiment, the lamp unit 20 does not have an imaging lens system including an imaging lens. However, the lamp unit 20 may have an imaging lens system through which light emitted from the optical system unit 50 is emitted. With such a configuration, a light distribution pattern wider than the light distribution pattern of the emitted light can be easily obtained. The width here indicates a width greater than that of a light distribution pattern formed on a vertical plane at a predetermined distance from the vehicle.
In the above embodiment, the incident points SR, SG, and SB have a substantially elliptical shape. However, the shapes of the incident points SR, SG, and SB are not particularly limited, and may be circular, for example.
In the above embodiment, the phase modulation elements 54R, 54G, 54B, and 54S are each substantially rectangular in shape, and the incident surfaces are also substantially rectangular. However, the incident surface of the phase modulation elements 54R, 54G, 54B, and 54S may have a shape in which the width in the vertical direction is larger than the width in the horizontal direction.
In the first embodiment, all of the three phase modulation elements 54R, 54G, and 54B are integrally formed. However, from the viewpoint of reducing the number of components, at least one phase modulation element of the plurality of phase modulation elements may be connected to at least one other phase modulation element and formed integrally with the other phase modulation element.
In the third embodiment, among the three light sources 52R, 52G, and 52B, the light sources 52R, 52G, and 52B emit light alternately. However, in view of reduction in the number of components and miniaturization, at least two light sources may be arranged so that light is emitted alternately for each of the light sources. In this case, the light emitted from the phase modulation element into which the light emitted from at least two light sources is incident is synthesized by an afterimage phenomenon, and the light synthesized by the afterimage phenomenon is synthesized with the light emitted from another phase modulation element to irradiate the light of a predetermined light distribution pattern.
In the first embodiment, the optical system unit 50 having the single phase modulation element assembly 54 in which the three light sources 52R, 52G, and 52B that emit laser beams in wavelength bands different from each other and the three phase modulation elements 54R, 54G, and 54B are integrated has been described as an example. In the second embodiment, the optical system unit 50 including the three light sources 52R, 52G, and 52B that emit laser beams in wavelength bands different from each other and the three phase modulation elements 54R, 54G, and 54B corresponding to the light sources 52R, 52G, and 52B in a one-to-one manner is described as an example. In the third embodiment, the optical system unit 50 including the three light sources 52R, 52G, and 52B that emit laser beams in wavelength bands different from each other and the single phase modulation element 54S is described as an example. However, the optical system unit may have at least one light source and a phase modulation element corresponding to the light source. For example, the optical system unit may include a light source that emits white laser light, and a phase modulation element that diffracts and emits the white laser light emitted from the light source. In the case where the optical system unit includes a plurality of light sources and phase modulation elements, each phase modulation element may correspond to at least one light source. For example, the light beams combined from the light sources may be made incident on one phase modulation element.
Industrial applicability
The present invention provides a vehicle lamp capable of forming a predetermined light distribution pattern while suppressing a decrease in energy efficiency, and is applicable to the field of vehicle lamps such as automobiles.
(third aspect)
Hereinafter, a mode for implementing the vehicle lamp of the present invention is exemplified together with the drawings. The following illustrative embodiments are provided for ease of understanding the present invention and are not intended to be limiting in any way. The present invention can be modified and improved according to the following embodiments without departing from the scope of the present invention.
(first embodiment)
Fig. 17 is a view showing the vehicle lamp according to the present embodiment, and is a view schematically showing a cross section in a vertical direction of the vehicle lamp. The vehicle lamp of the present embodiment is a headlamp 1 for an automobile. The automotive headlamps are respectively arranged in the left and right directions in front of the vehicle, and the left and right headlamps are configured to be substantially symmetrical in the left and right directions. Therefore, in the present embodiment, one headlamp will be described. As shown in fig. 17, the headlamp 1 of the present embodiment has a main configuration including a housing 10 and a lamp unit 20.
The housing 10 has a lamp housing 11, a front cover 12, and a rear cover 13 as main components. The front cover 12 is fixed to the lamp housing 11 so as to close a front opening of the lamp housing 11. An opening smaller than the front is formed in the rear of the lamp housing 11, and the rear cover 13 is fixed to the lamp housing 11 so as to close the opening.
A space formed by the lamp housing 11, the front cover 12 closing the opening in the front of the lamp housing 11, and the rear cover 13 closing the opening in the rear of the lamp housing 11 serves as a lamp chamber R in which the lamp unit 20 is housed.
The lamp unit 20 of the present embodiment has the heat sink 30, the cooling fan 35, the cover 40, and the optical system unit 50 as main components, and is fixed to the housing 10 by a structure not shown in the drawings.
The heat sink 30 has a metal bottom plate 31 extending substantially in the horizontal direction, and a plurality of heat radiating fins 32 are provided integrally with the bottom plate 31 on the lower surface side of the bottom plate 31. The cooling fan 35 is disposed with a gap from the heat radiation fins 32 and fixed to the heat sink 30. The radiator 30 is cooled by an air flow generated by the rotation of the cooling fan 35. Further, a cover 40 is disposed on the upper surface of the bottom plate 31 of the heat sink 30.
The cover 40 is fixed to the bottom plate 31 of the heat sink 30. The cover 40 is substantially rectangular and is made of metal such as aluminum, for example. An optical system unit 50 is housed in a space inside the cover 40. An opening 40H through which light emitted from the optical system unit 50 can pass is formed in the front portion of the cover 40. In order to impart light absorption to the inner walls of the cover 40, it is preferable to perform black alumite processing or the like on these inner walls. By making the inner walls of the cover 40 light-absorbing, even when light is irradiated to these inner walls due to unexpected reflection, or the like, reflection of the irradiated light can be suppressed and the light can be emitted from the opening 40H in an unexpected direction.
Fig. 18 is an enlarged view of the optical system unit shown in fig. 17. In fig. 18, the radiator 30, the cover 40, and the like are omitted for ease of understanding. As shown in fig. 18, the optical system unit 50 of the present embodiment includes a first light-emitting optical system 51R, a second light-emitting optical system 51G, a third light-emitting optical system 51B, a light guide optical system 155, and a phase modulation element assembly 54 in which a plurality of phase modulation elements are unitized.
The first light-emitting optical system 51R has a first light source 52R and a first collimating lens 53R. The first light source 52R is a laser element that emits laser light in a predetermined wavelength band, and in the present embodiment, is a semiconductor laser that emits red laser light having a peak wavelength of power of 638nm, for example. The optical system unit 50 includes a circuit board, not shown, on which the first light source 52R is mounted.
The first collimating lens 53R is a lens that collimates the laser light emitted from the first light source 52R in the fast axis direction and the slow axis direction. The red light LR emitted from the first collimating lens 53R is emitted from the first light-emitting optical system 51R. Instead of the first collimating lens 53R, a collimating lens for collimating the laser beam in the fast axis direction and a collimating lens for collimating the laser beam in the slow axis direction may be provided.
The second light emission optical system 51G includes a second light source 52G and a second collimator lens 53G, and the third light emission optical system 51B includes a third light source 52B and a third collimator lens 53B. The light sources 52G and 52B are laser elements that emit laser beams in predetermined wavelength bands, respectively. In the present embodiment, the second light source 52G is a semiconductor laser for emitting a green laser beam having a peak wavelength of power of, for example, 515nm, and the third light source 52B is a semiconductor laser for emitting a blue laser beam having a peak wavelength of power of, for example, 445 nm. Therefore, in the present embodiment, the three light sources 52R, 52G, and 52B emit laser beams in predetermined wavelength bands different from each other. These light sources 52G and 52B are mounted on the circuit board, respectively, in the same manner as the first light source 52R.
The second collimator lens 53G is a lens for collimating the fast axis direction and the slow axis direction of the laser beam emitted from the second light source 52G, and the third collimator lens 53B is a lens for collimating the fast axis direction and the slow axis direction of the laser beam emitted from the third light source 52B. The green light LG emitted from the second collimator lens 53G is emitted from the second light-emitting optical system 51G, and the blue light LB emitted from the third collimator lens 53B is emitted from the third light-emitting optical system 51B. Instead of the collimator lenses 53G and 53B, a collimator lens for collimating the laser beam in the fast axis direction and a collimator lens for collimating the laser beam in the slow axis direction may be provided.
The light guide optical system 155 guides the light LR emitted from the first light emitting optical system 51R, the light LG emitted from the second light emitting optical system 51G, and the light LB emitted from the third light emitting optical system 51B to the phase modulation element assembly 54. The light guide optical system 155 of the present embodiment includes a mirror 155m, a first optical element 155f, and a second optical element 155 s. The reflecting mirror 155m reflects the light LR emitted from the first light-emitting optical system 51R. The first optical element 155f transmits the light LR reflected by the reflecting mirror 155m and reflects the light LG emitted from the second light emission optical system 51G. The second optical element 155s transmits the light LR transmitted through the first optical element 155f and the light LG reflected by the first optical element 155f, and reflects the light LB emitted from the third light-emitting optical system 51B. As the first optical element 155f, the second optical element 155s may be a wavelength selective filter in which an oxide film is laminated on a glass substrate. By controlling the type and thickness of the oxide film, light having a wavelength longer than a predetermined wavelength can be transmitted, and light having a wavelength shorter than the predetermined wavelength can be reflected.
The light guide optical system 155 of the present embodiment outputs the lights LR, LG, and LB in parallel in the front-rear direction without multiplexing them, and inputs the lights LR, LG, and LB to the phase modulator assembly 54. In fig. 18, the light LR is indicated by a solid line, the light LG is indicated by a broken line, and the light LB is indicated by a one-dot chain line.
The phase modulation element assembly 54 diffracts the incident light to form a predetermined light distribution pattern. The phase modulation element assembly 54 of the present embodiment is arranged such that the incident surface EF on which light enters is inclined at approximately 45 degrees with respect to the vertical direction, and light LR, LG, and LB emitted from the light guide optical system 155 enters the incident surface EF. The angle of the incident surface EF with respect to the vertical direction is not particularly limited, and for example, the phase modulation element assembly 54 may be disposed so that the incident surface EF is substantially parallel to the vertical direction. In the present embodiment, the optical path length from the phase modulation element assembly 54 to the first light source 52R of the first light emission optical system 51R is longer than the optical path length from the phase modulation element assembly 54 to the second light source 52G of the second light emission optical system 51G. The optical path length from the phase modulation element assembly 54 to the second light source 52G of the second light emission optical system 51G is longer than the optical path length from the phase modulation element assembly 54 to the third light source 52B of the third light emission optical system 51B.
As described above, the phase modulation element aggregate 54 includes a plurality of phase modulation elements. Specifically, the phase modulation element aggregate 54 includes: a phase modulation element that diffracts the light LR from the first light-emitting optical system 51R to form the light LR into a predetermined light distribution pattern, a phase modulation element that diffracts the light LG from the second light-emitting optical system 51G to form the light LG into a predetermined light distribution pattern, and a phase modulation element that diffracts the light LB from the third light-emitting optical system 51B to form the light LB into a predetermined light distribution pattern. The three phase modulation elements are arranged in parallel in one direction, and the incident surface EF of the phase modulation element aggregate 54 is formed by the incident surfaces of the light of these phase modulation elements.
In the present embodiment, each of the three phase modulation elements is a reflective phase modulation element that reflects and diffracts incident light to emit the light, and specifically, is a reflective LCOS (Liquid Crystal On Silicon). Therefore, the phase modulation element assembly 54 is diffracted by the phase modulation elements corresponding to the light beams LR, LG, and LB incident on the incident surface EF, and the first light DLR diffracting the red light beam LR, the second light DLG diffracting the green light beam LG, and the third light DLB diffracting the blue light beam LB are emitted from the incident surface EF. The light DLR, DLG, and DLB thus emitted from the phase modulation element assembly 54 is emitted from the optical system unit 50. In fig. 17 and 18, the first light DLR is indicated by a solid line, the second light DLG is indicated by a broken line, and the third light DLB is indicated by a one-dot chain line. In addition, the、In fig. 17, the lights DLR, DLG, and DLB are shown as being shifted from each other.
Next, the structure of the phase modulation element assembly 54 of the present embodiment will be described in detail.
Fig. 19 is a front view of the phase modulation element assembly shown in fig. 18. Fig. 19 is a front view of the phase modulation element assembly 54 viewed from the incident surface EF side on which light is incident, and fig. 19 schematically shows the phase modulation element assembly 54. The phase modulation element assembly 54 of the present embodiment is formed in a substantially rectangular shape elongated in the vertical direction in the front view, and the entire region in the front view is the incident surface EF. Therefore, the incident surface EF of the phase modulation element assembly 54 can be understood as a substantially rectangular shape elongated in the vertical direction. In the following description, a direction parallel to the horizontal direction in the front view of the phase modulation element assembly 54 is a horizontal direction, and a direction perpendicular to the horizontal direction is a vertical direction. Therefore, the lateral direction is a direction parallel to the horizontal direction, the vertical direction is a direction parallel to a direction projected from the vertical direction to the incident surface EF, and the vertical direction is a direction parallel to the vertical direction in the front view.
The phase modulation element assembly 54 of the present embodiment includes: a first phase modulation element 54R corresponding to the first light emission optical system 51R, a second phase modulation element 54G corresponding to the second light emission optical system 51G, and a third phase modulation element 54B corresponding to the third light emission optical system 51B. The first phase modulation element 54R, the second phase modulation element 54G, and the third phase modulation element 54B are arranged adjacent to each other in the longitudinal direction, and the first phase modulation element 54R and the third phase modulation element 54B are connected to the second phase modulation element 54G. That is, the phase modulation element assembly has a structure in which the phase modulation elements 54R, 54G, and 54B are integrally formed. A drive circuit 60R is electrically connected to the phase modulation element assembly 54. The drive circuit 60R includes a scanning line drive circuit connected to the lateral side of the phase modulation element assembly 54 and a data line drive circuit connected to one side of the phase modulation element assembly 54 in the longitudinal direction. Electric power is supplied to the phase modulation elements 54R, 54G, and 54B constituting the phase modulation element assembly 54 through the drive circuit 60R.
The width in the lateral direction of the first phase modulation element 54R, the width in the lateral direction of the second phase modulation element 54G, and the width in the lateral direction of the third phase modulation element 54B are the same as the width W54 in the lateral direction of the phase modulation element aggregate 54. The width in the longitudinal direction of the first phase modulation element 54R, the width in the longitudinal direction of the second phase modulation element 54G, and the width in the longitudinal direction of the third phase modulation element 54B are smaller than the width W54 in the lateral direction of the phase modulation element aggregate 54. That is, the phase modulation elements 54R, 54G, and 54B are formed in a substantially rectangular shape elongated in the horizontal direction, i.e., the lateral direction. As described above, since the entire region of the phase modulation element assembly 54 in the front view is the incident surface EF, and the incident surface EF of the phase modulation element assembly 54 is configured by the incident surfaces of the light of the phase modulation elements 54R, 54G, and 54B, the incident surfaces of the light of the phase modulation elements 54R, 54G, and 54B are formed in a substantially rectangular shape elongated in the horizontal direction, i.e., in the lateral direction. The longitudinal direction of each of the phase modulation elements 54R, 54G, and 54B is substantially perpendicular to the longitudinal direction, which is the direction in which the phase modulation elements 54R, 54G, and 54B are arranged. Therefore, the longitudinal direction of the light incident surface of the phase modulation elements 54R, 54G, and 54B is substantially perpendicular to the longitudinal direction. In the present embodiment, the width in the vertical direction of the first phase modulation element 54R, the width in the vertical direction of the second phase modulation element 54G, and the width in the vertical direction of the third phase modulation element 54B are substantially the same. Therefore, the widths of the phase modulation elements 54R, 54G, and 54B in the longitudinal direction of the light incident surfaces are substantially the same.
The first phase modulation element 54R has a plurality of modulators MPR arranged in a matrix. The second phase modulation element 54G is provided with a plurality of modulation sections MPG arranged in a matrix, and the third phase modulation element 54B is provided with a plurality of modulation sections MPB arranged in a matrix. In the present embodiment, the modulators MPR, MPG, and MPB are squares having the same size. Therefore, the number of the modulators MPR arranged in the longitudinal direction of the incident surface of the first phase modulation element 54R is larger than the number of the modulators MPR arranged in the direction perpendicular to the longitudinal direction of the incident surface of the phase modulation element 54R. The number of the modulation sections MPG arranged in the longitudinal direction of the incident surface of the second phase modulation element 54G is larger than the number of the modulation sections MPG arranged in the direction perpendicular to the longitudinal direction of the incident surface of the second phase modulation element 54G, and the number of the modulation sections MPB arranged in the longitudinal direction of the incident surface of the third phase modulation element 54B is larger than the number of the modulation sections MPB arranged in the direction perpendicular to the longitudinal direction of the incident surface of the third phase modulation element 54B. Each of the modulators MPR, MPG, and MPB includes a plurality of dots arranged in a matrix, and diffracts and emits light incident on the modulators MPR, MPG, and MPB.
The red light LR emitted from the light guide optical system 155 is incident on the first phase modulation element 54R, and the first phase modulation element 54R emits the first light DLR diffracted by the light LR. The green light LG emitted from the light guide optical system 155 is incident on the second phase modulation element 54G, and the second phase modulation element 54G emits the second light DLG which diffracts the light LG. The blue light LB emitted from the light guide optical system 155 is incident on the third phase modulation element 54B, and the third phase modulation element 54B emits the third light DLB diffracted by the light LB.
Fig. 19 shows an incident point SR which is a region irradiated with red light LR, an incident point SG which is a region irradiated with green light LG, and an incident point SB which is a region irradiated with blue light LB. In the present embodiment, since the light sources 52R, 52G, and 52B are semiconductor laser light as described above, the laser light emitted from the light sources 52R, 52G, and 52B propagates while spreading in a substantially elliptical shape. The fast axis direction and slow axis direction of the laser beams emitted from the light sources 52R, 52G, and 52B are collimated by the collimating lenses 53R, 53G, and 53B, respectively, but the shapes of the laser beams are not adjusted. Thus, the light LR, LG, and LB having no shape adjusted is emitted from the light emitting optical systems 51R, 51G, and 51B, and is incident on the phase modulation element aggregate 54 via the light guide optical system 155. In the present embodiment, in the light guide optical system 155, since the shapes of the lights LR, LG, and LB are not adjusted, the shapes of the incident points SR, SG, and SB are substantially elliptical.
In the present embodiment, the size of the incident point SR having a substantially elliptical shape is such that at least one modulation unit MPR can be included, and the long axis LAR of the incident point SR is substantially parallel to the longitudinal direction, i.e., the lateral direction, of the incident surface of the first phase modulation element 54R. In other words, the incident point SR has a substantially elliptical shape that is long in the lateral direction, and the longitudinal direction of the incident point SR is not perpendicular to the longitudinal direction of the incident surface of the first phase modulation element 54R. The size of the incident point SG having a substantially elliptical shape is a size including at least one modulation unit MPG, and the long axis LAG of the incident point SG is substantially parallel to the longitudinal direction, i.e., the lateral direction, of the incident surface of the second phase modulation element 54G. In other words, the incident point SG has a substantially elliptical shape elongated in the lateral direction, and the longitudinal direction of the incident point SG is not perpendicular to the longitudinal direction of the incident surface of the second phase modulation element 54G. The size Wie of the incident point SB having a substantially elliptical shape can include the size of at least one modulation unit MPB, and the major axis LAB of the incident point SB is substantially parallel to the longitudinal direction, i.e., the lateral direction, of the incident surface of the third phase modulation element 54B. In other words, the incident point SB has a substantially elliptical shape elongated in the lateral direction, and the longitudinal direction of the incident point SB is not perpendicular to the longitudinal direction of the incident surface of the third phase modulating element 54B.
In the present embodiment, the width in the longitudinal direction, which is the direction perpendicular to the longitudinal direction of incident point SR, the width in the longitudinal direction, which is the direction perpendicular to the longitudinal direction of incident point SG, and the width in the longitudinal direction, which is the direction perpendicular to the longitudinal direction of incident point SB, are substantially the same. The width of incident point SR in the longitudinal direction, i.e., in the lateral direction, the width of incident point SG in the longitudinal direction, i.e., in the lateral direction, and the width of incident point SB in the longitudinal direction, i.e., in the lateral direction, are substantially the same. Further, the widths of the incident points SR, SG, SB may be different from each other.
Fig. 20 is a view schematically showing a part of a cross section in the thickness direction of the phase modulation element assembly shown in fig. 19. As shown in fig. 20, the phase modulation element assembly 54 of the present embodiment has a main configuration of a silicon substrate 62, a driving circuit layer 63, a plurality of electrodes 64, a reflective film 65, a liquid crystal layer 66, a transparent electrode 67, and a light-transmissive substrate 68.
The plurality of electrodes 64 are arranged in a matrix on one surface side of the silicon substrate 62 in a one-to-one correspondence with the respective points. The driving circuit layer 63 is a layer in which circuits connected to the scanning line driving circuit and the data line driving circuit of the driving circuit 60R shown in fig. 19 are arranged, and is arranged between the silicon substrate 62 and the plurality of electrodes 64. The transparent substrate 68 is disposed on one side of the silicon substrate 62 so as to face the silicon substrate 62, and is, for example, a glass substrate. The transparent electrode 67 is disposed on the surface of the translucent substrate 68 on the silicon substrate 62 side. The liquid crystal layer 66 has liquid crystal molecules 66a, and is disposed between the plurality of electrodes 64 and the transparent electrode 67. The reflective film 65 is disposed between the plurality of electrodes 64 and the liquid crystal layer 66, and is, for example, a dielectric multilayer film. The light RL emitted from the light guide optical system 155 enters from an entrance surface EF on the side opposite to the silicon substrate 62 side of the light transmissive substrate 68.
As shown in fig. 20, light RL incident from an incident surface EF on the side opposite to the silicon substrate 62 side of the transparent substrate 68 passes through the transparent electrode 67 and the liquid crystal layer 66, is reflected by the reflective film 65, passes through the liquid crystal layer 66 and the transparent electrode 67, and is emitted from the transparent substrate 68. When a voltage is applied between a specific electrode 64 and the transparent electrode 67, the alignment of the liquid crystal molecules 66a of the liquid crystal layer 66 located between the electrode 64 and the transparent electrode 67 changes. The change in the alignment of the liquid crystal molecules 66a changes the reflectance of the liquid crystal layer 66 between the electrode 64 and the transparent electrode 67, and changes the optical path length of the light RL transmitted through the liquid crystal layer 66. Therefore, when the light RL is transmitted through the liquid crystal layer 66 and emitted from the liquid crystal layer 66, the phase of the light RL emitted from the liquid crystal layer 66 can be changed according to the phase of the light RL incident on the liquid crystal layer 66. As described above, since the plurality of electrodes 64 are arranged for each point DT of the modulators MPR, MPG, and MPB, the alignment of the liquid crystal molecules 66a can be changed by controlling the voltage applied between the electrode 64 corresponding to each point DT and the transparent electrode 67, and the amount of change in the phase of light emitted from each point DT is adjusted according to each point DT. Since the lights having different phases interfere with each other and are diffracted, the light emitted from the point DT interferes and is diffracted, and the diffracted light is emitted from the phase modulation element assembly 54. Therefore, the phase modulation element assembly 54 can diffract and emit the incident light by adjusting the reflectance of the liquid crystal layer 66 at each point, and can make the light distribution pattern of the emitted light a desired light distribution pattern. The phase modulation element assembly 54 can change the light distribution pattern of the emitted light or change the direction of the emitted light to change the region to which the light is irradiated by changing the reflectance of the liquid crystal layer 66 at each point.
In the present embodiment, the same phase modulation pattern is formed in each of the modulation sections MPR of the first phase modulation element 54R of the phase modulation element assembly 54. The same phase modulation pattern is formed in each modulation section MPG of the second phase modulation element 54G, and the same phase modulation pattern is formed in each modulation section MPB of the third phase modulation element 54B. In the present specification, the phase modulation pattern means a pattern for modulating the phase of incident light. In the present embodiment, the phase modulation pattern is a pattern of the reflectance of the liquid crystal layer 66 at each point DT, and can be understood as a pattern of a voltage applied between the electrode 64 and the transparent electrode 67 corresponding to each point DT. By adjusting the phase modulation pattern, the light distribution pattern of the emitted light can be made to be a desired light distribution pattern. In the present embodiment, the phase modulation patterns of the modulators MPR, MPG, and MPB are different phase modulation patterns from each other.
Specifically, in the present embodiment, the phase modulation patterns of the modulators MPR, MPG, and MPB are phase modulation patterns that diffract the lights LR, LG, and LB, respectively, so that the light obtained by combining the first light DLR emitted from the first phase modulation element 54R, the second light DLG emitted from the second phase modulation element 54G, and the third light DLB emitted from the third phase modulation element 54B becomes a light distribution pattern of low beams. In other words, the phase modulation elements 54R, 54G, and 54B of the phase modulation element assembly 54 diffract the incident light LR, LG, and LB so that the light combined with the light DLR, DLG, and DLB emitted from the phase modulation elements 54R, 54G, and 54B becomes a light distribution pattern of low beam. The light distribution pattern also includes an intensity distribution. Therefore, in the present embodiment, the first light DLR emitted from the first phase modulation element 54R is an intensity distribution that overlaps with the light distribution pattern of the low beam and is based on the intensity distribution of the light distribution pattern of the low beam. The second light DLG emitted from the second phase modulation element 54G is an intensity distribution that overlaps the light distribution pattern of the low beam and is based on the intensity distribution of the light distribution pattern of the low beam. The third light DLB emitted from the third phase modulating element 54B is an intensity distribution that overlaps the light distribution pattern of the low beam and is based on the intensity distribution of the light distribution pattern of the low beam. As described above, the phase modulation elements 54R, 54G, and 54B have the plurality of modulation units MPR, MPG, and MPB that form the same phase modulation patterns, respectively, and diffract the light LR, LG, and LB so that the respective modulation units MPR, MPG, and MPB form the light distribution patterns. It is preferable that the phase modulation elements 54R, 54G, and 54B diffract the incident lights LR, LG, and LB so that the outer shape of the light distribution pattern of the lights DLR, DLG, and DLB emitted from the phase modulation elements 54R, 54G, and 54B matches the outer shape of the light distribution pattern of the low beam. In this way, the first phase modulation element 54R emits light DLR of a red component of the light distribution pattern of low beam, the second phase modulation element 54G emits light DLG of a green component of the light distribution pattern of low beam, and the third phase modulation element 54B emits light DLB of a blue component of the light distribution pattern of low beam.
Next, light emission from the headlamp 1 will be described. Specifically, a case where the low beam is emitted from the headlamp 1 will be described.
By supplying power from a power supply not shown to the light sources 52R, 52G, and 52B, respectively, the first light source 52R emits red laser light, the second light source 52G emits green laser light, and the third light source 52B emits blue laser light. These laser beams are collimated by the collimator lenses 53R, 53G, and 53B and then emitted from the light emitting optical systems 51R, 51G, and 51B. The light LR, LG, and LB emitted from the light emitting optical systems 51R, 51G, and 51B enters the light guide optical system 155.
In the light guide optical system 155, the light LR from the first light emission optical system 51R is reflected by the mirror 155m, passes through the first optical element 155f and the second optical element 155s, and is emitted from the light guide optical system 155. Thus, the light LR emitted from the light guide optical system 155 enters the first phase modulation element 54R of the phase modulation element assembly 54. That is, the light LR is guided to the first phase modulation element 54R of the phase modulation element assembly 54 by the light guide optical system 155. The light LG from the second light-emitting optical system 51G is reflected by the first optical element 155f, passes through the second optical element 155s, and is emitted from the light guide optical system 155. Thus, the light LG emitted from the light guide optical system 155 enters the second phase modulation element 54G of the phase modulation element assembly 54. That is, the light LG is guided to the second phase modulation element 54G of the phase modulation element assembly 54 by the light guide optical system 155. The light LB from the third light-emitting optical system 51B is reflected by the second optical element 155s and exits from the light guide optical system 155. The light LB thus emitted from the light guide optical system 155 enters the third phase modulation element 54B of the phase modulation element assembly 54. That is, the light LB is guided to the third phase modulating element 54B of the phase modulating element assembly 54 by the light guide optical system 155.
The first phase modulation element 54R of the phase modulation element assembly 54 diffracts the light LR incident on the first phase modulation element 54R to emit the first light DLR which is the red component of the light distribution pattern of low beam. The second phase modulation element 54G diffracts the light LG incident on the second phase modulation element 54G and emits the second light DLG, which is the green component of the near-light distribution pattern. The third phase modulating element 54B diffracts the light LB incident on the third phase modulating element 54B to emit third light DLB, which is a blue component of the low beam light distribution pattern. Thus, the lights DLR, DLG, and DLB emitted from the phase modulation element assembly 54 are irradiated to the outside of the headlamp 1 through the front cover 12. At this time, the lights DLR, DLG, and DLB are irradiated at the focal positions at predetermined distances from the vehicle so that the regions irradiated with the lights overlap with each other. The focal position is, for example, a position 25m from the vehicle. Since the light combined by these lights DLR, DLG, and DLB is a light distribution pattern of low beam, the irradiated light becomes low beam. It is preferable that the light DLR, DLG, and DLB have substantially the same outer shape of the light distribution pattern at the focal position.
Fig. 21 is a view showing a light distribution pattern for night illumination, specifically, fig. 21(a) is a view showing a light distribution pattern for low beams, and fig. 21(B) is a view showing a light distribution pattern for high beams. In fig. 21, S denotes a horizontal line, and the light distribution pattern is indicated by a thick line. The region PLA1 in the light distribution pattern PL of low beam, which is a light distribution pattern for night lighting shown in fig. 21(a), is a region with the highest intensity, and the intensity is reduced in the order of the region PLA2 and the region PLA 3. That is, the phase modulation elements 54R, 54G, and 54B of the phase modulation element assembly 54 diffract the synthesized light so that the light forms a light distribution pattern including the intensity distribution of the low beam. In fig. 21, as indicated by a broken line, light having a lower intensity than the low beam may be emitted from the headlamp 1 above the position where the low beam is emitted. The light is an optical OHS for identification. In this case, the light DLR, DLG, and DLB emitted from the respective phase modulation elements 54R, 54G, and 54B of the phase modulation element assembly 54 preferably includes the light OHS for identification. In this case, it can be understood that a light distribution pattern for night illumination is formed by using the low beam and the marker recognition light OHS. The light distribution pattern for night illumination is used not only at night but also in dark places such as tunnels.
As described above, the headlamp 1 of the present embodiment includes: light sources 52R, 52G, and 52B for emitting light; and a phase modulation element aggregate 54 including a first phase modulation element 54R, a second phase modulation element 54G, and a third phase modulation element 54B. The first phase modulation element 54R includes a plurality of modulators MPR for diffracting the light LR from the first light source 52R to form a predetermined light distribution pattern. The second phase modulation element 54G has a plurality of modulation portions MPG for diffracting the light LG from the second light source 52G to form a predetermined light distribution pattern. The third phase modulation element 54B has a plurality of modulation sections MPB for diffracting the light LB from the third light source 52B to form a predetermined light distribution pattern. The incident surface of the first phase modulation element 54R, the incident surface of the second phase modulation element 54G, and the incident surface of the third phase modulation element 54B are each a substantially rectangular shape elongated in the lateral direction. The incident point SR of the light LR of the first phase modulation element 54R, the incident point SG of the light LG of the second phase modulation element 54G, and the incident point SB of the light LB of the third phase modulation element 54B are each a substantially elliptical shape elongated in the lateral direction. The size of the incident point SR is such that the at least one modulation unit MPR can be included, the size of the incident point SG is such that the at least one modulation unit MPG can be included, and the size of the incident point SB is such that the at least one modulation unit MPB can be included. The longitudinal direction of the incident surface of the first phase modulation element 54R is not perpendicular to the longitudinal direction of the incident point SR, the longitudinal direction of the incident surface of the second phase modulation element 54G is not perpendicular to the longitudinal direction of the incident point SG, and the longitudinal direction of the incident surface of the third phase modulation element 54B is not perpendicular to the longitudinal direction of the incident point SB.
In the headlamp 1 of the present embodiment, the light LR from the first light source 52R can be incident on at least one modulator MPR, the light LG from the second light source 52G can be incident on at least one modulator MPG, and the light LB from the third light source 52B can be incident on at least one modulator MPB. Therefore, the light distribution pattern PL of low beams can be formed by the modulators MPR, MPG, and MPB. In the headlamp 1 according to the present embodiment, as described above, the incident surface of the first phase modulation element 54R, the incident surface of the second phase modulation element 54G, and the incident surface of the third phase modulation element 54B are each formed into a substantially rectangular shape elongated in the lateral direction. The incident point SR, the incident point SG, and the incident point SG each have a substantially elliptical shape elongated in the lateral direction. The longitudinal direction of the incident surface of the first phase modulation element 54R is not perpendicular to the longitudinal direction of the incident point SR, the longitudinal direction of the incident surface of the second phase modulation element 54G is not perpendicular to the longitudinal direction of the incident point SG, and the longitudinal direction of the incident surface of the third phase modulation element 54B is not perpendicular to the longitudinal direction of the incident point SB. Therefore, compared to the case where the longitudinal direction of the incident surface of the first phase modulation element 54R is perpendicular to the longitudinal direction of the incident point SR, the headlamp 1 of the present embodiment can suppress a part of the incident point SR from being exposed from the incident surface of the first phase modulation element 54R without adjusting the shape of the light LR from the first light source 52R. In addition, the headlamp 1 of the present embodiment can suppress the exposure of a part of the incident point SG from the incident surface of the second phase modulation element 54G without adjusting the shape of the light LG from the second light source 52G, as compared with the case where the longitudinal direction of the incident surface of the second phase modulation element 54G is perpendicular to the longitudinal direction of the incident point SG, and can suppress the exposure of a part of the incident point SB from the incident surface of the third phase modulation element 54B without adjusting the shape of the light LB from the third light source 52B, as compared with the case where the longitudinal direction of the incident surface of the third phase modulation element 54B is perpendicular to the longitudinal direction of the incident point SB. Therefore, the headlamp 1 of the present embodiment can suppress a decrease in energy efficiency and an increase in size.
In the headlamp 1 according to the present embodiment, the longitudinal direction of the incident surface of the first phase modulation element 54R is substantially parallel to the longitudinal direction of the incident point SR, the longitudinal direction of the incident surface of the second phase modulation element 54G is substantially parallel to the longitudinal direction of the incident point SG, and the longitudinal direction of the incident surface of the third phase modulation element 54B is substantially parallel to the longitudinal direction of the incident point SB. Therefore, the headlamp 1 according to the present embodiment can further suppress a part of the incident point SR from being exposed from the incident surface of the first phase modulation element 54R. Further, exposure of a part of the incident point SG from the incident surface of the second phase modulation element 54G and exposure of a part of the incident point SB from the incident surface of the third phase modulation element 54B can be further suppressed.
The headlamp 1 of the present embodiment includes a plurality of light sources 52R, 52G, and 52B, and the phase modulation element assembly 54 includes: a first phase modulation element 54R to which the light LR from the first light source 52R is incident, a second phase modulation element 54G to which the light LG from the second light source 52G is incident, and a third phase modulation element 54B to which the light LB from the third light source 52B is incident. That is, the phase modulation elements 54R, 54G, and 54B of the phase modulation element aggregate 54 are provided on the light sources 52R, 52G, and 52B for each light source. The phase modulation element assembly 54 has a first phase modulation element 54R and a third phase modulation element 54B connected to a second phase modulation element 54G, and these phase modulation elements 54R, 54G, and 54B are integrally formed. Therefore, in the headlamp 1 according to the present embodiment, the number of components can be reduced as compared with the case where the phase modulation elements 54R, 54G, and 54B are provided separately.
(second embodiment)
Next, a second embodiment of the present invention will be described in detail with reference to fig. 22 and 23. Note that the same or equivalent constituent elements as those of the first embodiment are denoted by the same reference numerals and redundant description thereof is omitted unless otherwise specified.
Fig. 22 is a diagram schematically showing an optical system unit according to a second embodiment of the present invention. Fig. 22 is a view of the optical system unit 50 viewed from the front side, that is, from the opening 40H side of the cover 40, and in fig. 22, for the sake of easy understanding, descriptions of the light DLR, DLG, DLB, and the like emitted from the heat sink 30, the cover 40, and the phase modulation element assembly 54 are omitted. As shown in fig. 22, the optical system unit 50 of the present embodiment is different from the optical system unit 50 of the first embodiment mainly in that the light guide optical system 155 is not provided.
In the optical system unit 50 of the present embodiment, as in the first embodiment, the phase modulation element assembly 54 is disposed such that the incident surface EF of incident light is inclined at approximately 45 degrees with respect to the vertical direction, and the light emission optical systems 51R, 51G, and 51B are disposed below the phase modulation element assembly 54. The light LR, LG, and LB emitted from the light-emitting optical systems 51R, 51G, and 51B are directly incident on the phase modulation element aggregate 54. In the present embodiment, the light sources 52R, 52G, and 52B are arranged in the left-right direction, and the light emission optical systems 51R, 51G, and 51B including the light sources 52R, 52G, and 52B are arranged in the left-right direction. The light LR, LG, and LB from the light-emitting optical systems 51R, 51G, and 51B arranged in this manner is incident on the phase modulation element assembly 54 in a state of being arranged in the left-right direction.
Fig. 23 is a front view of the phase modulation element assembly shown in fig. 22. Fig. 23 is a front view of the phase modulation element assembly 54 viewed from the incident surface EF side on which light is incident, and in fig. 23, the phase modulation element assembly 54 is schematically shown. As shown in fig. 23, the phase modulation element assembly 54 of the present embodiment is different from the phase modulation element assembly 54 of the first embodiment in that the directions in which the three phase modulation elements 54R, 54G, and 54B are adjacent to each other are different.
Specifically, the phase modulation element assembly 54 of the present embodiment is formed in a substantially rectangular shape elongated in the lateral direction, i.e., the lateral direction, in the front view. The three phase modulation elements 54R, 54G, and 54B are arranged adjacent to each other in the lateral direction, and the first phase modulation element 54R and the third phase modulation element 54B are connected to the second phase modulation element 54G. As in the first embodiment, the phase modulation elements 54R, 54G, and 54B are each a substantially rectangular shape elongated in the lateral direction, and the incident points SR, SG, and SB are each a substantially elliptical shape elongated in the lateral direction. Therefore, the longitudinal direction of the incident surface of the first phase modulation element 54R is not perpendicular to the longitudinal direction of the incident point SR, the longitudinal direction of the incident surface of the second phase modulation element 54G is not perpendicular to the longitudinal direction of the incident point SG, and the longitudinal direction of the incident surface of the third phase modulation element 54B is not perpendicular to the longitudinal direction of the incident point SB. The longitudinal direction of the incident surface of the phase modulation elements 54R, 54G, and 54B is substantially parallel to the lateral direction, which is the direction in which the phase modulation elements 54R, 54G, and 54B are arranged.
In the headlamp 1 of the present embodiment, as in the first embodiment, as compared with the case where the longitudinal direction of the incident surface of the first phase modulation element 54R is perpendicular to the longitudinal direction of the incident point SR, it is possible to suppress a part of the incident point SR from being exposed from the incident surface of the first phase modulation element 54R without adjusting the shape of the light LR from the first light source 52R. In addition, the headlamp 1 of the present embodiment can suppress the exposure of a part of the incident point SG from the incident surface of the second phase modulation element 54G without adjusting the shape of the light LG from the second light source 52G, as compared with the case where the longitudinal direction of the incident surface of the second phase modulation element 54G is perpendicular to the longitudinal direction of the incident point SG, and can suppress the exposure of a part of the incident point SB from the incident surface of the third phase modulation element 54B without adjusting the shape of the light LB from the third light source 52B, as compared with the case where the longitudinal direction of the incident surface of the third phase modulation element 54B is perpendicular to the longitudinal direction of the incident point SB. Therefore, the headlamp 1 of the present embodiment can suppress a decrease in energy efficiency and an increase in size.
In the headlamp 1 of the present embodiment, the three phase modulation elements 54R, 54G, and 54B are arranged adjacent to each other in the lateral direction. The light sources 52R, 52G, and 52B are arranged in the left-right direction in correspondence with the phase modulation elements 54R, 54G, and 54B, and light from the light sources 52R, 52G, and 52B is incident on the phase modulation element assembly 54 without passing through the light guide optical system 155. Therefore, the headlamp 1 of the present embodiment can have a simpler configuration than a headlamp without the light guide optical system 155. In the headlamp 1 of the present embodiment, the longitudinal direction of the incident surface of the phase modulation elements 54R, 54G, and 54B is substantially parallel to the lateral direction, which is the direction in which the phase modulation elements 54R, 54G, and 54B are arranged. Therefore, the distance between the centers of the first phase modulation element 54R and the second phase modulation element 54G and the distance between the centers of the second phase modulation element 54G and the third phase modulation element 54B increase as compared with the case where the longitudinal direction of the incident surface of the adjacent parallel phase modulation elements 54R, 54G, 54B is perpendicular to the direction in which the phase modulation elements 54R, 54G, 54B are parallel. Therefore, the distance between the first light source 52R and the second light source 52G and the distance between the second light source 52G and the third light source 52B can be increased as compared with the case where the longitudinal direction of each of the incident surfaces of the adjacent phase modulation elements 54R, 54G, 54B is perpendicular to the direction in which the phase modulation elements 54R, 54G, 54B are arranged. Therefore, the headlamp 1 of the present embodiment can further increase the size of the light sources 52R, 52G, and 52B as compared with the case where the longitudinal direction of the incident surface of the adjacent phase modulation elements 54R, 54G, and 54B is perpendicular to the direction in which the phase modulation elements 54R, 54G, and 54B are arranged. In addition, the headlamp 1 of the present embodiment can suppress interference between the adjacent first light source 52R and second light source 52G and between the second light source 52G and third light source 52B. In addition, the headlamp 1 of the present embodiment can suppress overheating of the light sources 52R, 52G, and 52B due to thermal interference between the adjacent first light source 52R and second light source 52G and between the second light source 52G and third light source 52B.
(third embodiment)
Next, a third embodiment of the present invention will be described in detail with reference to fig. 24. Note that the same or equivalent constituent elements as those of the first embodiment are denoted by the same reference numerals and redundant description thereof is omitted unless otherwise specified.
Fig. 24 is a view showing an optical system unit according to a third embodiment of the present invention, similarly to fig. 18. In fig. 24, the radiator 30, the cover 40, and the like are omitted for ease of understanding. As shown in fig. 24, the optical system unit 50 of the present embodiment is different from the optical system unit 50 of the first embodiment in that the phase modulation elements 54R, 54G, and 54B are separated from each other and a combining optical system 55 is provided instead of the light guide optical system 155.
The phase modulation elements 54R, 54G, and 54B of the present embodiment are LCOS, similarly to the phase modulation elements 54R, 54G, and 54B of the first embodiment. The first phase modulation element 54R is formed in a substantially rectangular shape elongated in the lateral direction when viewed from the front side of the incident surface EFR on which light is incident. Therefore, the width of the incidence surface EFR of the first phase modulation element 54R in the lateral direction is larger than the width of the incidence surface EFR of the first phase modulation element 54R in the longitudinal direction. The first phase modulation element 54R is formed with a plurality of modulation units MPR arranged in a matrix, and the number of modulation units MPR arranged in the longitudinal direction of the incident surface EFR of the first phase modulation element 54R is larger than the number of modulation units MPR arranged in the direction perpendicular to the longitudinal direction of the incident surface EFR of the first phase modulation element 54R. The light LR from the first light source 52R enters the first phase modulation element 54R, and the first phase modulation element 54R emits the first light DLR that diffracts the light LR. In the present embodiment, as in the first embodiment, since the shape of the light LR from the first light source 52R serving as the semiconductor laser light is not adjusted, the shape of the incident point SR of the first phase modulation element 54R has a substantially elliptical shape. In the present embodiment, as in the first embodiment, the size of the incident point SR having a substantially elliptical shape is such that at least one modulation unit MPR can be included, and the major axis LAR of the incident point SR is substantially parallel to the longitudinal direction of the incident surface EFR of the phase modulation element 54R.
The second phase modulation element 54G of the present embodiment is formed in a substantially rectangular shape elongated in the lateral direction when viewed from the front side of the incident surface EFG on which light is incident. Therefore, the width of the incident surface EFG of the second phase modulation element 54G in the lateral direction is larger than the width of the incident surface EFG of the second phase modulation element 54G in the longitudinal direction. The second phase modulation element 54G is formed with a plurality of modulation sections MPG arranged in a matrix, and the number of modulation sections MPG arranged in the longitudinal direction of the incident surface EFG of the second phase modulation element 54G is larger than the number of modulation sections MPG arranged in the direction perpendicular to the longitudinal direction of the incident surface EFG of the second phase modulation element 54G. The light LG from the second light source 52G enters the second phase modulation element 54G, and the second phase modulation element 54G emits the second light DLG which diffracts the light LG. In the present embodiment, as in the first embodiment, since the shape of the light LG from the second light source 52G, which is a semiconductor laser light, is not adjusted, the shape of the incident point SG of the second phase modulation element 54G is substantially elliptical. In the present embodiment, as in the first embodiment, the size of the incident point SG having a substantially elliptical shape is such that at least one modulation section MPG can be included, and the long axis LAG of the incident point SG is substantially parallel to the longitudinal direction of the incident surface EFG of the second phase modulation element 54G.
The third phase modulating element 54B of the present embodiment is formed in a substantially rectangular shape elongated in the lateral direction when viewed from the front side of the incident surface EFB on which light is incident. Therefore, the width of the incidence surface EFB of the third phase modulation element 54B in the lateral direction is larger than the width of the incidence surface EFB of the third phase modulation element 54B in the longitudinal direction. A plurality of modulation sections MPB arranged in a matrix are formed in the third phase modulation element 54B, and the number of modulation sections MPB arranged in the longitudinal direction of the incident surface EFB of the third phase modulation element 54B is larger than the number of modulation sections MPB arranged in the direction perpendicular to the longitudinal direction of the incident surface EFB of the third phase modulation element 54B. The light beam LB from the third light source 52B enters the third phase modulation element 54B, and the third phase modulation element 54B emits the third light DLB which diffracts the light beam LB. In the present embodiment, as in the first embodiment, since the shape of the light LB from the third light source 52B as the semiconductor laser light is not adjusted, the shape of the incident point SB of the phase modulation element 54B is substantially elliptical. In the present embodiment, as in the first embodiment, the size of the incident point SB having a substantially elliptical shape is such that at least one modulation unit MPB can be included, and the major axis LAB of the incident point SB is substantially parallel to the longitudinal direction of the incident surface EFB of the third phase modulation element 54B.
The combining optical system 55 of the present embodiment includes a first optical element 55f and a second optical element 55 s. The first optical element 55f is an optical element that combines the first light DLR emitted from the first phase modulation element 54R and the second light DLG emitted from the second phase modulation element 54G. In the present embodiment, the first optical element 55f combines the first light DLR and the second light DLG by transmitting the first light DLR and reflecting the second light DLG. The second optical element 55s is an optical element that combines the first light DLR and the second light DLG combined by the first optical element 55f and the third light DLB emitted from the third phase modulating element 54B. In the present embodiment, the second optical element 55s transmits the first light DLR and the second light DLG combined by the first optical element 55f and reflects the third light DLB, thereby combining the first light DLR, the second light DLG, and the third light DLB. As such a first optical element 55f and a second optical element 55s, a wavelength selective filter in which an oxide film is laminated on a glass substrate can be cited. By controlling the type and thickness of the oxide film, light having a wavelength longer than a predetermined wavelength can be transmitted, and light having a wavelength shorter than the predetermined wavelength can be reflected.
In this way, the first light DLR, the second light DLG, and the third light DLB are combined in the combining optical system 55, and the combined light is emitted from the combining optical system 55. In fig. 24, the first light DLR is indicated by a solid line, the second light DLG is indicated by a broken line, and the third light DLB is indicated by a one-dot chain line, and these lights DLR, DLG, and DLB are shown as being shifted from each other.
In the present embodiment, the phase modulation elements 54R, 54G, and 54B diffract the light LR, LG, and LB from the light sources 52R, 52G, and 52B, respectively, so that the light DLR, DLG, and DLB emitted from the phase modulation elements 54R, 54G, and 54B, respectively, is synthesized by the synthesis optical system 55 and then diffracted into the light distribution pattern PL of low beam. Therefore, the first light DLR, which is the light of the red component of the light distribution pattern PL of low beam, is emitted from the first phase modulation element 54R, the second light DLG, which is the light of the green component of the light distribution pattern PL of low beam, is emitted from the second phase modulation element 54G, and the third light DLB, which is the light of the blue component of the light distribution pattern PL of low beam, is emitted from the third phase modulation element 54B.
In this way, the lights DLR, DLG, and DLB are combined in the combining optical system 55, and the combined white light is emitted from the opening 40H of the cover 40, and the light is emitted from the headlamp 1 through the front cover 12. Since this light has the light distribution pattern PL of the low beam, the irradiated light becomes the low beam.
In the headlamp 1 of the present embodiment, as in the first embodiment, as compared with the case where the longitudinal direction of the incident surface EFR of the first phase modulation element 54R is perpendicular to the longitudinal direction of the incident point SR, it is possible to suppress a part of the incident point SR from being exposed from the incident surface EFR of the first phase modulation element 54R without adjusting the shape of the light LR from the first light source 52R. In addition, the headlamp 1 of the present embodiment can suppress the exposure of a part of the incident point SG from the incident surface EFG of the second phase modulation element 54G without adjusting the shape of the light LG from the second light source 52G, as compared with the case where the longitudinal direction of the incident surface EFG of the second phase modulation element 54G is perpendicular to the longitudinal direction of the incident point SG, and can suppress the exposure of a part of the incident point SB from the incident surface EFB of the third phase modulation element 54B without adjusting the shape of the light LB from the third light source 52B, as compared with the case where the longitudinal direction of the incident surface EFB of the third phase modulation element 54B is perpendicular to the longitudinal direction of the incident point SB. Therefore, the pump dog of the headlamp 1 according to the present embodiment can suppress the reduction in energy efficiency and the increase in size.
(fourth embodiment)
Next, a fourth embodiment of the present invention will be described in detail with reference to fig. 25. Note that the same or equivalent constituent elements as those of the first embodiment are denoted by the same reference numerals and redundant description thereof is omitted unless otherwise specified.
Fig. 25 is a view showing an optical system unit according to a fourth embodiment of the present invention, similarly to fig. 18. In fig. 25, the radiator 30, the cover 40, and the like are omitted for ease of understanding. As shown in fig. 25, the optical system unit 50 of the present embodiment is different from the optical system unit 50 of the first embodiment mainly in that one phase modulation element 54S is provided instead of the phase modulation element aggregate 54.
In the present embodiment, the phase modulation element 54S has the same configuration as the phase modulation elements 54R, 54G, and 54B of the first embodiment. The phase modulation element 54S is formed in a substantially rectangular shape elongated in the lateral direction when viewed from the front side of the incident surface EFS on which light is incident. Therefore, the width of the incident surface EFS of the phase modulation element 54S in the lateral direction is larger than the width of the incident surface EFS of the phase modulation element 54S in the longitudinal direction. The phase modulation element 54S is formed with a plurality of modulation sections arranged in a matrix, and the number of modulation sections arranged in the longitudinal direction of the incident surface EFS of the phase modulation element 54S is larger than the number of modulation sections arranged in the direction perpendicular to the longitudinal direction of the incident surface EFS of the phase modulation element 54S.
In the present embodiment, the light LR, LG, and LB emitted from the light emitting optical systems 51R, 51G, and 51B is guided to the phase modulation element 54S by the light guide optical system 155 and is incident on the phase modulation element 54S, as in the first embodiment. Therefore, the incidence of these lights LR, LG, and LB on the phase modulator 54S will be described below with reference to fig. 18. In the present embodiment, the power supplied to the light sources 52R, 52G, and 52B is adjusted, laser light is alternately emitted to each of the light sources 52R, 52G, and 52B, and light LR, LG, and LB is alternately emitted to each of the light emitting optical systems 51R, 51G, and 51B. That is, when the first light-emitting optical system 51R emits light LR, the second light-emitting optical system 51G and the third light-emitting optical system 51B do not emit light LG or LB, when the second light-emitting optical system 51G emits light LG, the first light-emitting optical system 51R and the third light-emitting optical system 51B do not emit light LR or LB, and when the third light-emitting optical system 51B emits light LB, the first light-emitting optical system 51R and the second light-emitting optical system 51G do not emit light LR or LG. Emission of laser light from the light sources 52R, 52G, and 52B is sequentially switched, and emission of light LR, LG, and LB from the light emitting optical systems 51R, 51G, and 51B is sequentially switched. Therefore, the lights LR, LG, and LB having different wavelength bands from each other and emitted from the light-emitting optical systems 51R, 51G, and 51B are sequentially incident on the phase modulator 54S. The phase modulation element 54S sequentially emits the light DLR, DLG, and DLB obtained by diffracting the incident light LR, LG, and LB. In fig. 25, the lights DLR, DLG, and DLB are shown as being shifted from each other.
In the present embodiment, as in the first embodiment, since the shapes of the lights LR, LG, and LB from the light sources 52R, 52G, and 52B serving as the semiconductor lasers are not adjusted, the incident points of the lights LR, LG, and LB of the phase modulator 54S have a substantially elliptical shape. In the present embodiment, the incident points having the substantially elliptical shape have sizes that can include at least one modulation unit, and the long axes of the incident points are substantially parallel to the longitudinal direction of the incident surface EFS of the phase modulation element 54S. In addition, these points of incidence coincide with each other.
Next, the light emitted from the phase modulation element 54S of the present embodiment will be described. Specifically, a case where the headlamp 1 emits light of the light distribution pattern PL of low beam will be described as an example.
In the present embodiment, the phase modulation element 54S changes the phase modulation pattern in synchronization with the switching of the emission of the laser light from each of the light sources 52R, 52G, and 52B. Specifically, when the light LR from the light source 52R enters the phase modulation element 54S, the phase modulation pattern corresponding to the light source 52R, that is, the phase modulation pattern of the light of the red component of the light distribution pattern of the low beam is formed by the first light DLR emitted from the phase modulation element 54S. Therefore, when the light LR from the light source 52R enters, the phase modulation element 54S emits the first light DLR which is the light of the red component of the light distribution pattern of the low beam. When the light LG from the light source 52G enters, the phase modulation element 54S forms a phase modulation pattern corresponding to the light source 52G, that is, the phase modulation pattern of the green component light of the light distribution pattern of the low beam is formed by the second light DLG emitted from the phase modulation element 54S. Therefore, when the light LG from the light source 52G enters, the phase modulation element 54S emits the second light DLG, which is the green component of the light distribution pattern of the low beam. When the light LB from the light source 52B enters the phase modulation element 54S, the phase modulation pattern corresponding to the light source 52B, that is, the phase modulation pattern of the blue component light of the light distribution pattern of the low beam is formed by the third light DLB emitted from the phase modulation element 54S. Therefore, when the light LB from the light source 52B enters, the phase modulation element 54S emits the third light DLB, which is the blue component of the light distribution pattern of the low beam.
That is, the phase modulation element 54S changes the phase modulation pattern in accordance with the wavelength band of the light LR, LG, and LB thus incident, and sequentially emits the first light DLR, which is the light of the red component of the low beam, the second light DLG, which is the light of the green component of the low beam, and the third light DLB, which is the light of the blue component of the low beam. These lights DLR, DLG, and DLB are emitted from the opening 40H of the cover 40, and are sequentially irradiated to the outside of the headlamp 1 through the front cover 12. At this time, the first light DLR, the second light DLG, and the third light DLB are irradiated at the focal positions at predetermined distances from the vehicle so that the regions irradiated with the light overlap each other. The focal position is, for example, a position 25m from the vehicle. It is preferable that the first light DLR, the second light DLG, and the third light DLB are irradiated so that the outlines of the regions irradiated with the respective lights DLR, DLG, and DLB at the focal position substantially match each other. In the present embodiment, since the emission time lengths of the laser beams emitted from the light sources 52R, 52G, and 52B are substantially the same, the emission time lengths of the light beams DLR, DLG, and DLB are also substantially the same.
In addition, when lights having different colors are repeatedly irradiated at a cycle shorter than the time resolution of human vision, a human can recognize that the lights having the different colors are irradiated by synthesizing the lights due to an afterimage phenomenon. In the present embodiment, when the time for emitting the laser light again from the light source 52R after emitting the laser light from the light source 52R is shorter than the time resolution for human vision, the light DLR, DLG, and DLB emitted from the phase modulation element 54S are repeatedly irradiated at a cycle shorter than the time resolution for human vision, and the red light DLR, the green light DLG, and the blue light DLB are combined due to the afterimage phenomenon. As described above, the emission time lengths of the light DLR, DLG, and DLB are substantially the same, and the intensities of the laser beams emitted from the light sources 52R, 52G, and 52B are predetermined intensities as in the first embodiment. Therefore, the color of the light synthesized by the afterimage phenomenon is the same white as the light after the light DLR, DLG, DLB synthesis of the first embodiment. Further, since the light distribution pattern of the light after the light DLR, DLG, and DLB is synthesized is the light distribution pattern PL of the low beam, the light distribution pattern of the light after the light DLR, DLG, and DLB is synthesized by the afterimage phenomenon also becomes the light distribution pattern PL of the low beam. Thus, the light of the light distribution pattern PL of the low beam is emitted from the headlamp 1.
The cycle of repeatedly emitting laser light from the light sources 52R, 52G, and 52B is preferably 1/15s or less from the viewpoint of suppressing the perception of flicker of light synthesized by the afterimage phenomenon. The temporal resolution of human vision is approximately 1/30 s. In a vehicle lamp, when the light emission cycle is about 2 times, the flicker of the sensed light can be suppressed. When the period is 1/30s or less, the time resolution of human vision is substantially exceeded. Therefore, the flicker of the sensed light can be further suppressed. In addition, from the viewpoint of further suppressing the flicker of the sensed light, the period is preferably 1/60s or less.
In the present embodiment, as described above, the longitudinal direction of the incident surface EFS of the phase modulation element 54S is not perpendicular to the longitudinal direction of the incident point of each of the light LR, LG, LB from the light sources 52R, 52G, 52B. Therefore, in the headlamp 1 of the present embodiment, similarly to the first embodiment, even without adjusting the shapes of the lights LR, LG, and LB from the light sources 52R, 52G, and 52B, the exposure of a part of the incident point of each of the lights LR, LG, and LB from the incident surface EFS of the phase modulator 54S can be suppressed. Therefore, the headlamp 1 of the present embodiment can suppress a decrease in energy efficiency and an increase in size. In addition, in the headlamp 1 of the present embodiment, since the phase modulation elements diffracted by the light LR, LG, and LB from the three light sources 52R, 52G, and 52B can be shared, the number of components can be reduced, and the size can be reduced.
The present invention has been described above by taking the above embodiments as examples, but the present invention is not limited thereto.
The vehicle lamp of the invention comprises: a light source; a phase modulation element having at least one modulation section for diffracting light from the light source to form a predetermined light distribution pattern; the light incident surface of the phase modulation element and the light incident point of the phase modulation element are long in a predetermined direction compared to other directions, and the size of the incident point is a size that can include at least one modulation unit. In comparison with the case where the longitudinal direction of the incident surface of the phase modulation element is perpendicular to the longitudinal direction of the incident point, the vehicle lamp configured as described above can suppress exposure of a part of the incident point from the incident surface of the phase modulation element without adjusting the shape of the light from the light source, and can suppress a decrease in energy efficiency and an increase in size.
In the above embodiment, the headlight 1 serving as the vehicle lamp irradiates low beams, but the present invention is not particularly limited thereto. For example, the vehicle lamp may emit high beam or light constituting an image. When the vehicle lamp is irradiated with high beam, light of a light distribution pattern PH of high beam, which is a light distribution pattern for night illumination shown in fig. 21(B), is irradiated. In the distribution pattern PH of high beam in fig. 21(B), the region PHA1 is the region with the highest intensity, and the region PHA2 is the region with lower intensity than the region PHA 1. That is, the phase modulation elements 54R, 54G, and 54B of the phase modulation element assembly 54 according to the first and second embodiments diffract light so that the combined light forms a light distribution pattern including the intensity distribution of the high beam. The phase modulation elements 54R, 54G, and 54B according to the second embodiment diffract light so that the combined light forms a light distribution pattern including the intensity distribution of the high beam. The phase modulation element 54S according to the third embodiment diffracts light so that the light synthesized by the afterimage phenomenon forms a light distribution pattern including the intensity distribution of the high beam. In addition, when the vehicle lamp irradiates light constituting an image, the direction of light emitted from the vehicle lamp and the position where the vehicle lamp is mounted on the vehicle are not particularly limited.
In the above embodiment, the phase modulation elements 54R, 54G, 54B, and 54S are reflective phase modulation elements. However, as the phase modulation element, for example, an lcd (liquid crystal display) which is a liquid crystal panel, a glv (grating Light valve) in which a plurality of reflectors are formed on a silicon substrate, a diffraction grating, or the like may be used. The LCD is a transmissive phase modulation element. In this LCD, similarly to the LCOS which is the reflective liquid crystal panel, the voltage applied between the pair of electrodes sandwiching the liquid crystal layer is controlled at each point, and the amount of change in the phase of light emitted from each point is adjusted, whereby the light distribution pattern of the emitted light can be made to be a desired light distribution pattern. Further, the pair of electrodes is not a transparent electrode. GLV is a reflective phase modulation element. The GLV diffracts incident light to emit the light and makes a light distribution pattern of the emitted light a desired light distribution pattern by electrically controlling the deflection of the reflector.
In the first embodiment, the first phase modulation element 54R, the second phase modulation element 54G, and the third phase modulation element 54B of the phase modulation element assembly 54 are arranged adjacent to each other in the longitudinal direction, and in the second embodiment, the first phase modulation element 54R, the second phase modulation element 54G, and the third phase modulation element 54B of the phase modulation element assembly 54 are arranged adjacent to each other in the lateral direction. However, the direction in which the phase modulation elements 54R, 54G, and 54B are arranged is not particularly limited, and may be arranged in the longitudinal direction and the lateral direction, for example.
In the first and third embodiments, the light guide optical system 155 includes the reflecting mirror 155m, the first optical element 155f, and the second optical element 155 s. However, the light guide optical system 155 is not limited to the configurations of the first and fourth embodiments described above, as long as it guides the light LR, LG, and LB emitted from the light emitting optical systems 51R, 51G, and 51B to the phase modulation element aggregate 54 and the phase modulation element 54S. For example, the light guide optical system 155 may not have the reflecting mirror 155 m. In this case, the light LR emitted from the first light-emitting optical system 51R enters the first optical element 155 f. In the first and fourth embodiments, band pass filters that transmit light in a predetermined wavelength range and reflect light in other wavelength ranges may be used for the first and second optical elements 155f and 155 s.
In the first and fourth embodiments, the optical system unit 50 includes the light guide optical system 155 that guides the light LR, LG, and LB emitted from the light emitting optical systems 51R, 51G, and 51B to the phase modulation element aggregate 54 and the phase modulation element 54S. However, the optical system unit 50 may not have the light guide optical system 155. In this case, the light emitting optical systems 51R, 51G, and 51B are arranged so that the light LR, LG, and LB enters the phase modulation element aggregate 54 and the phase modulation element 54S.
In the third embodiment, the first optical element 55f transmits the first light DLR and reflects the second light DLG to combine the first light DLR and the second light DLG, and the second optical element 55s transmits the first light DLR and the second light DLG combined by the first optical element 55f and reflects the third light DLB to combine the first light DLR, the second light DLG, and the third light DLB. However, for example, the third light DLB and the second light DLG may be combined in the first optical element 55f, and the third light DLB and the second light DLG combined in the first optical element 55f may be combined with the first light DLR in the second optical element 55 s. In this case, in the third embodiment, the positions of the first light source 52R, the first collimating lens 53R, the first phase modulation element 54R, the third light source 52B, the third collimating lens 53B, and the third phase modulation element 54B may be replaced. In the third embodiment, a band-pass filter that transmits light in a predetermined wavelength band and reflects light in other wavelength bands may be used for the first optical element 55f and the second optical element 55 s. In the third embodiment, the combining optical system 55 may combine the lights DLR, DLG, and DLB emitted from the phase modulation elements 54R, 54G, and 54B, and is not limited to the configuration of the third embodiment and the configuration described above.
In the third embodiment, the optical system unit 50 includes the combining optical system 55 that combines the first light DLR, the second light DLG, and the third light DLB. However, the optical system unit 50 may not have the synthesizing optical system 55. In this case, as in the first embodiment, the phase modulation elements 54R, 54G, and 54B diffract the incident light LR, LG, and LB so that the light DLR, DLG, and DLB emitted from the phase modulation elements 54R, 54G, and 54B are combined.
In the first and second embodiments, the optical system unit 50 does not include a synthesis optical system that synthesizes the first light DLR, the second light DLG, and the third light DLB. However, the optical system unit 50 according to the first and second embodiments may have a composite optical system as in the third embodiment.
In the second embodiment, the optical system unit 50 does not have a light guide optical system for guiding the light LR, LG, and LB emitted from the light emitting optical systems 51R, 51G, and 51B to the phase modulation element assembly 54. In the third embodiment, the optical system unit 50 does not include a light guide optical system for guiding the light LR, LG, and LB emitted from the light emitting optical systems 51R, 51G, and 51B to the phase modulation elements 54R, 54G, and 54B. However, the optical system unit 50 according to the second and third embodiments may have a light guide optical system, as in the first embodiment.
In addition, in the above embodiment, the lamp unit 20 does not have an imaging lens system including an imaging lens. However, the lamp unit 20 may have an imaging lens system through which light emitted from the optical system unit 50 is emitted. With such a configuration, a light distribution pattern wider than the light distribution pattern of the emitted light can be easily obtained. The width here indicates a width greater than that of a light distribution pattern formed on a vertical plane at a predetermined distance from the vehicle.
In the above embodiment, the incident points SR, SG, and SB have a substantially elliptical shape. However, the shapes of the incident points SR, SG, SB may be long in a predetermined direction compared to other directions.
In the above embodiment, the phase modulation elements 54R, 54G, 54B, and 54S are each substantially rectangular in shape, and the incident surfaces are also substantially rectangular. However, the incident surface of the phase modulation elements 54R, 54G, 54B, and 54S may have a long shape that is longer in a predetermined direction than in other directions.
In the above embodiment, the longitudinal direction of the incident surface of each of the phase modulation elements 54R, 54G, 54B, and 54S is the horizontal direction, i.e., the lateral direction. However, the longitudinal direction of the incident surface of the phase modulation elements 54R, 54G, 54B, and 54S is not particularly limited, and may be the vertical direction, i.e., the vertical direction.
In the first and second embodiments, all of the three phase modulation elements 54R, 54G, and 54B are integrally formed. However, from the viewpoint of reducing the number of components, at least one phase modulation element of the plurality of phase modulation elements may be connected to at least one other phase modulation element and formed integrally with the other phase modulation element.
In the second embodiment, all of the three phase modulation elements 54R, 54G, and 54B are arranged adjacent to each other. However, at least two phase modulation elements may be arranged in parallel, and the longitudinal direction of each of the incident surfaces of the at least two phase modulation elements arranged in parallel to the direction in which the phase modulation elements are arranged. For example, in the second embodiment, the third phase modulation element 54B of the phase modulation element assembly 54 may be provided separately from the phase modulation element assembly 54.
In the fourth embodiment, among the three light sources 52R, 52G, and 52B, the light sources 52R, 52G, and 52B emit light alternately. However, in view of reduction in the number of components and miniaturization, at least two light sources may be arranged so that light is emitted alternately for each of the light sources. In this case, the light emitted from the phase modulation element into which the light emitted from at least two light sources is incident is synthesized by an afterimage phenomenon, and the light synthesized by the afterimage phenomenon is synthesized with the light emitted from another phase modulation element to irradiate the light of a predetermined light distribution pattern.
In the first and second embodiments, the optical system unit 50 having the single phase modulation element assembly 54 in which the three light sources 52R, 52G, and 52B that emit laser beams in wavelength bands different from each other and the three phase modulation elements 54R, 54G, and 54B are integrated has been described as an example. In the third embodiment, the optical system unit 50 including the three light sources 52R, 52G, and 52B that emit laser beams in wavelength bands different from each other and the three phase modulation elements 54R, 54G, and 54B corresponding to the light sources 52R, 52G, and 52B in a one-to-one manner is described as an example. In the fourth embodiment, the optical system unit 50 including the three light sources 52R, 52G, and 52B that emit laser beams in wavelength bands different from each other and the single phase modulation element 54S is described as an example. However, the optical system unit may have at least one light source and a phase modulation element corresponding to the light source. For example, the optical system unit may include a light source that emits white laser light, and a phase modulation element that diffracts and emits the white laser light emitted from the light source. In the case where the optical system unit includes a plurality of light sources and phase modulation elements, each phase modulation element may correspond to at least one light source. For example, the light beams combined from the light sources may be made incident on one phase modulation element.
Industrial applicability
The present invention provides a vehicle lamp that can suppress a decrease in energy efficiency and a size increase, and can be used in the field of vehicle lamps such as automobiles.
(fourth aspect)
Hereinafter, a mode for implementing the vehicle lamp of the present invention is exemplified together with the drawings. The following examples are given for the purpose of facilitating understanding of the present invention and are not intended to limit the present invention. The present invention can be modified and improved according to the following embodiments without departing from the scope of the present invention. In addition, in the drawings referred to below, the dimensions of the respective component parts are sometimes changed for easy understanding.
(first embodiment)
Fig. 26 is a view showing an example of the vehicle lamp according to the present embodiment, and is a vertical cross-sectional view schematically showing a vertical cross-section of the vehicle lamp. In the present embodiment, the vehicle lamp is a vehicle headlamp 1. As shown in fig. 26, the vehicle headlamp 1 includes a housing 10 and a lamp unit 20 as main components.
The housing 10 has a lamp housing 11, a front cover 12, and a rear cover 13 as main components. An opening is formed in the front of the lamp housing 11, and the front cover 12 is fixed to the lamp housing 11 so as to close the opening. An opening smaller than the front is formed in the rear of the lamp housing 11, and the rear cover 13 is fixed to the lamp housing 11 so as to close the opening.
A space formed by the lamp housing 11, the front cover 12 closing the opening in the front of the lamp housing 11, and the rear cover 13 closing the opening in the rear of the lamp housing 11 serves as a lamp chamber R in which the lamp unit 20 is housed.
The lamp unit 20 of the present embodiment includes a heat sink 30, a cooling fan 35, a cover 40, and an optical system unit 50 as main components. The lamp unit 20 is fixed to the housing 10 by a structure not shown. The desired light is generated by the optical system unit 50, and exits from the lamp unit 20.
In the present embodiment, the heat sink 30 has a metal bottom plate 31 extending substantially in the front-rear direction, and a plurality of heat radiating fins 32 are provided integrally with the bottom plate 31 on the lower surface side of the bottom plate 31. The cooling fan 35 is disposed with a gap from the heat radiation fins 32, and is fixed to the heat sink 30. The radiator 30 is cooled by an air flow generated by the rotation of the cooling fan 35. A cover 40 is fixed to the upper surface of the bottom plate 31 of the heat sink 30.
The cover 40 is fixed to the bottom plate 31 of the heat sink 30. The cover 40 is substantially rectangular and is made of metal such as aluminum, for example. The optical system unit 50 is housed in a space inside the cover 40. Further, an opening 40H through which light emitted from the optical system unit 50 can pass is formed in front of the cover 40. Further, the inner wall of the cover 40 preferably has light absorption by black alumina film processing or the like. By making the inner wall of the cover 40 light-absorbing, unwanted reflection is suppressed, and light irradiated to the inner wall of the cover 40 by refraction or the like is reflected and emitted from the opening 40H in an unwanted direction.
Fig. 27 is an enlarged view of the optical system unit 50 of the lamp unit 20. As shown in fig. 27, the optical system unit 50 of the present embodiment includes a first light source 52R, a second light source 52G, a third light source 52B, a phase modulation element assembly 54 in which a plurality of phase modulation elements are unitized, and a light guide optical system 155 as main components. The light emitted from the light sources 52R, 52G, and 52B is incident on the phase modulation element assembly 54 via the light guide optical system 155.
The first light source 52R, the second light source 52G, and the third light source 52B are disposed at predetermined positions of the lamp chamber R, and are fixed to the bottom plate 31 of the heat sink 30 by a structure not shown in the drawings. In the present embodiment, the light sources 52R, 52G, and 52B are arranged in the lamp chamber R such that the optical path length from the second light source 52G to the phase modulation element assembly 54 is longest, and the optical path length from the third light source 52B to the phase modulation element assembly 54 is shortest.
The first light source 52R is a laser element that emits red laser light, and in the present embodiment, laser light having a peak wavelength of power of 638nm, for example, is emitted upward. The second light source 52G is a laser element that emits green laser light, and in the present embodiment, laser light of 515nm, for example, is emitted forward at the peak wavelength of power. The third light source 52B is a laser element that emits blue laser light, and in the present embodiment, laser light having a peak wavelength of power of, for example, 445nm is emitted forward.
In the present embodiment, the total number of red laser beams emitted from the first light source 52R, the total number of green laser beams emitted from the second light source 52G, and the total number of blue laser beams emitted from the third light source 52B are the same.
A first collimating lens 53R is disposed above the first light source 52R. A second collimator lens 53G is disposed in front of the second light source 52G. A third collimator lens 53B is disposed in front of the third light source 52B. These collimator lenses 53R, 53G, and 53B are fixed to the cover 40 by a structure not shown, and can collimate the laser light in the fast axis direction and the slow axis direction.
The fast axis direction and the slow axis direction of the laser beam may be collimated by providing a collimator lens for collimating the fast axis direction of the laser beam and a collimator lens for collimating the slow axis direction of the laser beam, respectively.
The light guide optical system 155 includes a first optical element 155f and a second optical element 155 s. The first optical element 155f is disposed above the first collimator lens 53R and in front of the second collimator lens 53G, and is inclined by about 45 ° with respect to the front-rear direction and the vertical direction. The first optical element 155f is, for example, a wavelength selective filter in which an oxide film is laminated on a glass substrate, and the type and thickness of the oxide film are adjusted so that light having a wavelength longer than a predetermined wavelength is transmitted and light having a wavelength shorter than the predetermined wavelength is reflected. In the present embodiment, the first optical element 155f transmits the light of the red component emitted from the first light source 52R and reflects the light of the green component emitted from the second light source 52G. In the present embodiment, the red laser beam emitted from the first collimator lens 53R and the green laser beam emitted from the second collimator lens 53G are emitted upward from different positions on the emission surface of the first optical element 155 f.
The second optical element 155s is disposed above the first optical element 155f and in front of the third collimator lens 53B, and is inclined by about 45 ° with respect to the same direction as the first optical element 155f in the front-rear direction and the up-down direction. The second optical element 155s is a wavelength selective filter, similarly to the first optical element 155 f. In the present embodiment, the second optical element 155s is configured to transmit the light of the red component emitted from the first light source 52R and the light of the green component emitted from the second light source 52G and reflect the light of the blue component emitted from the third light source 52B. In the present embodiment, the red laser beam emitted from the first optical element 155f, the green laser beam emitted from the first optical element 155f, and the blue laser beam emitted from the third collimator lens 53B are emitted upward from different positions on the emission surface of the second optical element 155 s.
The phase modulation element assembly 54 is disposed above the light guide optical system 155, and is inclined by about 45 ° with respect to the same direction as the optical elements 155f and 155s in the front-rear direction and the up-down direction. As described above, the phase modulation element aggregate 54 includes a plurality of phase modulation elements. Specifically, the phase modulation element assembly 54 includes a first phase modulation element 54R that modulates the phase of the red laser beam to form a predetermined light distribution pattern, a second phase modulation element 54G that modulates the phase of the green laser beam to form a predetermined light distribution pattern, and a third phase modulation element 54B that modulates the phase of the blue laser beam to form a predetermined light distribution pattern, and these phase modulation elements 54R, 54G, and 54B are arranged in one direction.
In the present embodiment, each of the phase modulation elements 54R, 54G, and 54B is a reflective phase modulation element that reflects incident light and diffracts the incident light to emit the light, and specifically, is a reflective LCOS (Liquid Crystal on silicon).
Next, the structure of the phase modulation element assembly 54 will be described in detail.
Fig. 28 is a front view schematically showing the phase modulation elements 54R, 54G, and 54B. As shown in fig. 28, the phase modulation element assembly 54 is formed in a substantially rectangular shape in front view, and includes a first phase modulation element 54R positioned at the uppermost portion, a second phase modulation element 54G positioned below the first phase modulation element 54R, and a third phase modulation element 54B positioned below the second phase modulation element 54G. A drive circuit 60R is electrically connected to the phase modulation element assembly 54. The drive circuit 60R includes a scan line drive circuit connected to one of the long sides of the phase modulation element assembly 54 and a data line drive circuit connected to one of the short sides of the phase modulation element 54R. Electric power is supplied to the phase modulation elements 54R, 54G, and 54B constituting the phase modulation element assembly 54 through the drive circuit 60R.
The first phase modulation element 54R is formed of a plurality of modulators MPR divided in a matrix. Each modulator MPR includes a plurality of dots arranged in a matrix, reflects and diffracts the incident red laser beam, and emits the diffracted red laser beam. The second phase modulation element 54G is formed of a plurality of modulation units MPG divided in a matrix. Each of the modulators MPG includes a plurality of dots arranged in a matrix, and diffracts the incident green laser light while reflecting the incident green laser light, and causes the diffracted green laser light to be diffracted. The third phase modulation element 54B is formed of a plurality of modulation sections MPB divided in a matrix. Each of the modulators MPB includes a plurality of dots arranged in a matrix, diffracts the incident blue laser beam, and emits the diffracted blue laser beam. In fig. 28, an incident point SR of the red laser beam incident on the first phase modulation element 54R is indicated by a solid line, an incident point SG of the green laser beam incident on the second phase modulation element 54G is indicated by a broken line, and an incident point SB of the blue laser beam incident on the third phase modulation element 54B is indicated by a one-dot chain line. In the present embodiment, the incident point SB of the blue laser beam is the largest and the incident point SG of the green laser beam is the smallest among the incident points SR, SG, SB. That is, the longer the optical path length from the light source to the phase modulation element assembly 54, the smaller the spot diameter. In fig. 28, the incident points SR, SG, and SB are shown as circles, and the outline of the incident points may be other than a circle, for example, an ellipse.
Fig. 29 is a view schematically showing a cross section in the thickness direction of a part of the phase modulation element assembly 54 shown in fig. 28. As shown in fig. 29, the phase modulation element assembly 54 of the present embodiment has a main configuration of a silicon substrate 62, a driving circuit layer 63, a plurality of electrodes 64, a reflective film 65, a liquid crystal layer 66, a transparent electrode 67, and a light-transmissive substrate 68.
The plurality of electrodes 64 are arranged in a matrix corresponding to the respective points on one surface side of the silicon substrate 62. The driving circuit layer 63 is a layer in which circuits connected to the scanning line driving circuit and the data line driving circuit of the driving circuit 60R shown in fig. 28 are arranged, and is arranged between the silicon substrate 62 and the plurality of electrodes 64. The light-transmitting substrate 68 is disposed on one side of the silicon substrate 62 so as to face the silicon substrate 62, and is, for example, a glass substrate. The transparent electrode 67 is disposed on the surface of the translucent substrate 68 on the silicon substrate 62 side. The liquid crystal layer 66 has a plurality of liquid crystal molecules 66a, and is disposed between the plurality of electrodes 64 and the transparent electrode 67. The reflective film 65 is disposed between the plurality of electrodes 64 and the liquid crystal layer 66, and is, for example, a dielectric multilayer film. The red laser light, the green laser light, and the blue laser light are incident from the surface of the translucent substrate 68 on the side opposite to the silicon substrate 62 side.
As shown in fig. 29, light RL incident from the surface of the translucent substrate 68 on the side opposite to the silicon substrate 62 side passes through the transparent electrode 67 and the liquid crystal layer 66, is reflected by the reflective film 65, passes through the liquid crystal layer 66 and the transparent electrode 67, and is emitted from the translucent substrate 68. Here, when a voltage is applied between a specific electrode 64 and the transparent electrode 67, the alignment of the liquid crystal molecules 66a of the liquid crystal layer 66 located between the electrode 64 and the transparent electrode 67 changes. The light distribution of the liquid crystal molecules 66a changes, and the refractive index of the liquid crystal layer 66 located between the electrode 64 and the transparent electrode 67 changes, thereby changing the optical path length of the light RL transmitted through the liquid crystal layer 66. As described above, since the plurality of electrodes 64 are arranged corresponding to each point of the modulators MPR, MPG, and MPB, the alignment of the liquid crystal molecules 66a at each point can be changed by controlling the voltage applied between the electrode 64 corresponding to each point and the transparent electrode 67. Thus, the amount of change in the phase of the light RL emitted from each point is adjusted for each point, and the phase modulation patterns of the respective modulation units MPR, MPG, and MPB can be adjusted to predetermined phase modulation patterns.
In the present embodiment, the modulators MPR of the first phase modulation element 54R each have the same phase modulation pattern corresponding to the red laser beam. The modulation units MPG of the second phase modulation element 54G have the same phase modulation pattern corresponding to the green laser beam. The modulators MPB of the third phase modulating element 54B have the same phase modulation pattern corresponding to the blue laser beam.
In the present embodiment, when the entire incident point SR is incident on the first phase modulation element 54R as shown in fig. 28, at least one modulation unit MPR is included in the incident point SR. As described above, since each of the modulators MPR has the same phase modulation pattern, when the entire incident point SR enters the first phase modulation element 54R, the light distribution pattern of the red laser beam emitted from the first phase modulation element 54R becomes a predetermined light distribution pattern based on the phase modulation pattern of the modulator MPR. In the present embodiment, the predetermined light distribution pattern is a light distribution pattern capable of forming a light distribution pattern of low beams. Hereinafter, the red laser light emitted from the phase modulation element assembly 54 may be referred to as first light DLR.
When the entire incident point SG is incident on the second phase modulation element 54G as shown in fig. 28, the incident point SG includes at least one modulation unit MPG. As described above, since each of the modulators MPG has the same phase modulation pattern, when the entire incident point SG is incident on the second phase modulation element 54G, the light distribution pattern of the green laser beam emitted from the second phase modulation element 54G becomes a predetermined light distribution pattern based on the phase modulation pattern of the modulator MPG. In the present embodiment, the predetermined light distribution pattern is a light distribution pattern capable of forming a light distribution pattern of low beams. Hereinafter, the green laser light emitted from the phase modulation element assembly 54 may be referred to as second light DLG.
When the entire incident point SB is incident on the third phase modulation element 54B as shown in fig. 28, at least one modulation unit MPB is included at the incident point SB. As described above, since each of the modulators MPB has the same phase modulation pattern, when the entire incident point SB is incident on the third phase modulating element 54B, the light distribution pattern of the blue laser beam emitted from the third phase modulating element 54B becomes a predetermined light distribution pattern based on the phase modulation pattern of the modulator MPB. In the present embodiment, the predetermined light distribution pattern is a light distribution pattern capable of forming a light distribution pattern of low beams. Hereinafter, the blue laser light emitted from the phase modulation element assembly 54 may be referred to as third light DLB.
Next, the emission of light from the vehicle headlamp 1 will be described. Specifically, a case where the low beam is emitted from the vehicle headlamp 1 will be described.
When power is supplied to the first light source 52R, red laser light is generated by the first light source 52R. As shown in fig. 27, the red laser beam is emitted upward and collimated by the first collimating lens 53R. When power is supplied to the second light source 52G, the second light source 52G generates green laser light, and the green laser light is emitted forward. The green laser light is collimated by the second collimator lens 53G. When power is supplied to the third light source 52B, the third light source 52B generates blue laser light, and the blue laser light is emitted forward. The blue laser light is collimated by the third collimator lens 53B.
The red laser beam emitted from the first collimating lens 53R passes through the first optical element 155f disposed above the first collimating lens 53R, as described above. As described above, the green laser beam emitted from the second collimator lens 53G is reflected by the first optical element 155f disposed in front of the second collimator lens 53G. That is, the green laser beam is converted by the first optical element 155f to 90 degrees and emitted forward. As described above, the red laser beam and the green laser beam are emitted from different positions on the emission surface of the first optical element 155 f. Therefore, the red laser light and the green laser light emitted from the first optical element 155f propagate upward in a state of being substantially aligned in the front-rear direction.
As described above, the red laser beam and the green laser beam pass through the second optical element 155s disposed above the first optical element 155 f. As described above, the blue laser beam emitted from the third collimator lens 53B is reflected by the second optical element 155s disposed in front of the third collimator lens 53B. That is, the blue laser beam is converted by the second optical element 155s by 90 degrees and emitted forward. As described above, the red laser light, the green laser light, and the blue laser light are emitted from different positions on the emission surface of the second optical element 155 s. Therefore, the red laser light, the green laser light, and the blue laser light emitted from the second optical element 155s propagate upward in a state of being arranged substantially in the front-rear direction. Specifically, the red laser beam and the blue laser beam are positioned on the foremost side and the blue laser beam is positioned on the rearmost side, respectively.
As described above, in a state where the red laser beam is positioned on the frontmost side and the blue laser beam is positioned on the rearmost side, the red laser beam, the green laser beam, and the blue laser beam propagate upward, and as a result, the red laser beam enters the first phase modulation element 54R of the phase modulation element assembly 54 disposed above the second optical element 155 s. The green laser light is incident on the second phase modulation element 54G of the phase modulation element assembly 54. The blue laser beam enters the third phase modulation element 54B of the phase modulation element assembly 54.
In the present embodiment, as described above, the optical path length of the green laser beam from the second light source 52G to the phase modulation element assembly 54 is the longest and the optical path length of the blue laser beam from the third light source 52B to the phase modulation element assembly 54 is the shortest among the optical path lengths from the light sources to the phase modulation element assembly 54.
The red laser light incident on the first phase modulation element 54R is diffracted by the first phase modulation element 54R to become the first light DLR. The first light DLR is emitted forward from the first phase modulation element 54R. As described above, the first light DLR becomes a light distribution pattern of low beams. The green laser light incident on the second phase modulation element 54G is diffracted by the second phase modulation element 54G to become second light DLG. The second light DLG is emitted forward from the second phase modulation element 54G. As described above, the second light DLG becomes a light distribution pattern of low beams. The blue laser light incident on the third phase modulation element 54B is diffracted by the third phase modulation element 54B to become third light DLB. The third light DLB is emitted forward from the third phase modulating element 54B. As described above, the third light DLB becomes a light distribution pattern of low beams.
Thus, the light DLR, DLG, and DLB emitted from the phase modulation element assembly 54 are all light distribution patterns of low beams. Therefore, the lights DLR, DLG, and DLB are emitted from the opening 40H of the cover 40 and propagate forward only by a predetermined distance, and the lights DLR, DLG, and DLB are superimposed on each other, whereby the low beam PL as white light shown in fig. 30 can be formed. In fig. 30, the light distribution pattern is indicated by a thick line, and the straight line S indicates a horizontal line. The region PLA1 is a region having the highest light intensity, and the light intensity is reduced in the order of the region PLA2 and the region PLA 3.
When the vehicle on which the vehicle headlamp 1 is mounted vibrates and the light sources 52R, 52G, and 52B vibrate, the laser beams emitted from the light sources 52R, 52G, and 52B also vibrate, and therefore the incident points SR, SG, and SB may move on the incident surface of the phase modulation element assembly 54. In this case, when the distance over which the incident point moves is large, the incident point may be exposed to the outside of the phase modulation element assembly 54 or may be exposed to a different phase modulation element. For example, a case where an incident point of a laser beam of a predetermined color is exposed to a phase modulation element corresponding to a laser beam of a different color is considered. In this case, since the phase modulation pattern of the exposed region is a phase modulation pattern corresponding to the laser light of a different color, the light distribution pattern of the laser light of the predetermined color emitted from the exposed region can be a light distribution pattern different from the low beam. Further, by mixing light having a light distribution pattern different from such low beams with the outgoing light of the vehicle headlamp 1, the formation of the low beams PL can be inhibited.
When the light source is oscillated as described above, the oscillation width of the incident point of the light at the irradiation position tends to increase as the optical path length to the irradiation position becomes longer. In the vehicle headlamp 1 according to the present embodiment, as described above, the incident point SG of the green laser beam is smaller than the incident points SR and SB as the spot diameter of the light having the longer optical path length from the light source to the phase modulation element assembly 54 is smaller, as shown in fig. 28. Therefore, even when the incident point SG of the green laser beam is greatly moved by vibration of the vehicle or the like, exposure of the incident point SG to the first phase modulation element 54R and the third phase modulation element 54B can be suppressed. Therefore, with the vehicle headlamp 1 of the present embodiment, it is possible to suppress the breakage of a desired light distribution pattern such as the low beam PL.
In this way, since the size of the incident point of each laser beam is varied according to the optical path length to the irradiation position, exposure of the spot diameter from the phase modulation element can be suppressed without providing an optical system or the like for adjusting the size of the incident point, and an increase in the number of components can be suppressed.
Note that the incident points SR and SB of the red laser beam and the blue laser beam, which have longer optical path lengths than the green laser beam, may be set to the same size, and only the size of the incident point SG may be reduced. That is, of at least two lights having different incident point sizes, the incident point may be made smaller as the light having a longer optical path length to the phase modulation element is longer. As described above, the longer the optical path length from the light source to the phase modulation element assembly 54, the smaller the incident point, and the size of the incident point corresponding to the length of the optical path length is set, so that a desired light distribution pattern can be more easily obtained.
(second embodiment)
Next, a second embodiment of the present invention will be explained. Note that the same or equivalent constituent elements as those of the first embodiment are denoted by the same reference numerals and redundant description thereof is omitted except for the case of special description.
Fig. 31 is a view showing the lamp unit 20 of the vehicle headlamp 1 according to the second embodiment of the present invention, similarly to fig. 27. In fig. 31, the heat sink 30, the cover 40, and the like of the lamp unit 20 are omitted for ease of understanding. As shown in fig. 31, the lamp unit 20 according to the second embodiment is different from the lamp unit 20 according to the first embodiment in that a phase modulation element assembly 54 is configured by providing a phase modulation element for each light source, in that one phase modulation element 54S is provided. The configuration of the lamp unit 20 according to the second embodiment will be described below.
In the present embodiment, the first light source 52R emits the red laser beam upward, the second light source 52G emits the green laser beam forward, and the third light source 52B emits the blue laser beam forward. These red, green, and blue laser beams enter the phase modulation element 54S through the combining optical system 55. These light sources 52R, 52G, and 52B are arranged in the lamp chamber R such that the optical path length from the second light source 52G to the phase modulation element 54S is longest and the optical path length from the third light source 52B to the phase modulation element 54S is shortest. The total number of beams of the red laser beam, the green laser beam, and the blue laser beam in the present embodiment is the same as that in the first embodiment.
Fig. 32 is a front view schematically showing the phase modulation element 54S shown in fig. 31. As shown in fig. 32, in the present embodiment, the incident point SG of the green laser beam having the longest optical path length to the phase modulation element 54S is the smallest, and the incident point SB of the blue laser beam having the shortest optical path length to the phase modulation element 54S is the largest. In fig. 32, the incident points SR, SG, and SB are shown as circles, and the outline of the incident points may be an ellipse instead of a circle.
The light sources 52R, 52G, and 52B of the present embodiment are connected to a control system not shown. The control system does not emit light from the light sources 52G, 52B while the light source 52R emits red laser light, does not emit light from the light sources 52R, 52B while the light source 52G emits green laser light, and does not emit light from the light sources 52R, 52G while the light source 52B emits blue laser light. That is, the vehicle headlamp 1 of the present embodiment switches the emission of light from the light sources 52R, 52G, and 52B at predetermined intervals based on the control of the control system.
In addition, as in the first embodiment, the laser beams emitted from the light sources 52R, 52G, and 52B are collimated by the collimator lenses 53R, 53G, and 53B.
As shown in fig. 31, a combining optical system 55 is provided above the collimator lens 53R and in front of the collimator lenses 53G and 53B. That is, a first optical element 55f is provided above the collimator lens 53R and in front of the collimator lens 53G, and a second optical element 55s is provided above the first optical element 55f and in front of the collimator lens 53B. These optical elements 55f and 55s are arranged to be inclined by about 45 ° in the same direction in the front-rear direction and the up-down direction.
A phase modulation element 54S is provided above the second optical element 55S. The phase modulation element 54S is disposed at a position where the red laser light, the green laser light, and the blue laser light that have passed through the combining optical system 55 can enter. The phase modulation element 54S of the present embodiment is, for example, a reflective LCOS. The phase modulation element 54S is disposed to be inclined by about 45 ° in the front-rear direction and the up-down direction, and the inclination direction thereof is the same direction as the optical elements 55f and 55S.
Next, light emission from the lamp unit 20 of the present embodiment will be described. Specifically, a case where the low beam is emitted from the vehicle headlamp 1 will be described.
As described above, the lamp unit 20 of the present embodiment switches the emission of light from the light sources 52R, 52G, and 52B at predetermined intervals based on the control of the control system. For example, first, the red laser beam is emitted from the first light source 52R for a predetermined time. During this time, the laser beams from the light sources 52G and 52B are not emitted. The red laser beam is collimated by the collimator lens 53R and then enters the phase modulation element 54S through the combining optical system 55. As shown in fig. 32, the red laser beam is incident on the incident surface of the phase modulation element 54S at an incident point SR of a predetermined size.
When the red laser light enters the phase modulation element 54S, the red laser light is diffracted and reflected by the phase modulation element 54S, and the first light DLR having the light distribution pattern of the low beam is emitted forward.
When the predetermined time has elapsed, the light from the light source 52R is in a state of not being emitted, and instead of emitting light from the light source 52R, the green laser light is emitted from the light source 52G for the predetermined time. The green laser beam is collimated by the collimator lens 53G and then enters the phase modulation element 54S through the combining optical system 55. As described above, the green laser beam enters the incident surface of the phase modulation element 54S at the incident point SG smaller than the incident point SR of the red laser beam.
When the green laser light enters the phase modulation element 54S, the green laser light is diffracted and reflected by the phase modulation element 54S, and the second light DLG having the light distribution pattern of the low beam PL is emitted forward.
When the predetermined time has elapsed, the light from the light source 52G is not emitted, and instead of emitting light from the light source 52G, the blue laser light is emitted from the light source 52B for the predetermined time. The blue laser light is collimated by the collimator lens 53B and then enters the phase modulation element 54S through the combining optical system 55. As described above, the blue laser beam is incident on the incident surface of the phase modulation element 54S at the incident point SB larger than the incident point SR of the red laser beam.
When the blue laser light enters the phase modulation element 54S, the blue laser light is diffracted and reflected by the phase modulation element 54S, and the third light DLB having the light distribution pattern of the low beam is emitted forward.
The light emission cycle is repeated at a predetermined cycle by the control of the control system.
In this way, the control system switches the emission of light from the light sources 52R, 52G, and 52B at predetermined intervals, and thus switches the emission of light DLR, DLG, and DLB from the vehicle headlamp 1 at predetermined intervals. In the case where the period is shorter than the time resolution of human vision, an afterimage effect is produced, and a human can recognize that lights of different colors are illuminated as if they were synthesized. Therefore, by making the above-described cycle of the present embodiment shorter than the time resolution of a human, the human can recognize that the low beam PL, which is white light, is emitted from the vehicle headlamp 1.
Since the time resolution of human vision is approximately 1/30s, the period is preferably 1/30s or less, and more preferably 1/60s or less. Even when the period is larger than 1/30s, the afterimage effect is produced. For example, even if the period is 1/15s, the afterimage effect can be produced.
As described above, according to the vehicle headlamp 1 of the present embodiment, the incident point SG of the green laser beam having a longer optical path length to the phase modulation element assembly 54 is the smallest as compared with the red laser beam and the blue laser beam, and therefore, as in the first embodiment, even when the incident point SG of the green laser beam is moved greatly by vibration of the vehicle or the like, exposure of the incident point SG from the phase modulation element 54S can be suppressed. Therefore, with the vehicle headlamp 1 of the present embodiment, a desired light distribution pattern such as the low beam PL is easily obtained.
In this way, since the size of the incident point of each laser beam is varied according to the optical path length to the irradiation position, it is possible to suppress the exposure of the spot diameter from the phase modulation element and to suppress the increase in the number of components without providing an optical system or the like for adjusting the size of the incident point. In addition, in the vehicle headlamp 1 according to the present embodiment, since the laser beams from the light sources 52R, 52G, and 52B are incident on the common phase modulation element 54S, the number of phase modulation elements can be reduced and one phase modulation element can be used, and an increase in the number of components can be more effectively suppressed.
(third embodiment)
Next, a third embodiment of the present invention will be explained. Note that the same or equivalent constituent elements as those of the first embodiment are denoted by the same reference numerals and redundant description thereof is omitted except for the case of special description.
Fig. 33 is a view showing the lamp unit 20 of the vehicle headlamp 1 according to the third embodiment of the present invention, similarly to fig. 27. As shown in fig. 33, the lamp unit 20 of the third embodiment is different from the lamp unit 20 of the first embodiment in that the phase modulation elements 54R, 54G, and 54B are disposed apart from each other. Hereinafter, the lamp unit 20 of the third embodiment will be described.
As shown in fig. 33, the optical system unit 50 of the lamp unit 20 of the present embodiment has, as main components, a first light source 52R, a second light source 52G, a third light source 52B, a first phase modulation element 54R, a second phase modulation element 54G, a third phase modulation element 54B, and a composite optical system 55. In the present embodiment, the phase modulation elements 54R, 54G, and 54B are reflective phase modulation elements that reflect incident light and diffract incident light to emit light, and specifically, are reflective LCOS.
The first light source 52R emits red laser light of a predetermined total number of beams upward. The second light source 52G emits the green laser beam having a total number of beams greater than that of the red laser beam rearward. The third light source 52B emits the blue laser beam having a total number of beams greater than that of the green laser beam rearward. That is, in the present embodiment, the total number of beams of the red laser beam is the smallest, and the total number of beams of the blue laser beam is the largest.
In addition, as in the first embodiment, the laser beams emitted from the light sources 52R, 52G, and 52B are collimated by the collimator lenses 53R, 53G, and 53B.
The first phase modulation element 54R is disposed above the first collimating lens 53R, and is inclined by about 45 ° with respect to the front-rear direction and the vertical direction. The red laser beam collimated by the collimator lens 53R enters the incident surface of the first phase modulation element 54R at an incident point SR of a predetermined size.
The second phase modulation element 54G is disposed behind the second collimator lens 53G, and is inclined at about 45 ° in a direction opposite to the first phase modulation element 54R with respect to the front-back direction and the vertical direction. The green laser beam collimated by the collimator lens 53G enters the incident surface of the second phase modulation element 54G at an incident point SG larger than the incident point SR.
The third phase modulation element 54B is disposed behind the third collimator lens 53B, and is inclined at about 45 ° in a direction opposite to the first phase modulation element 54R with respect to the front-rear direction and the up-down direction. The blue laser beam collimated by the collimator lens 53B enters the incident surface of the third phase modulating element 54B at an incident point SB larger than the incident point SG.
As described above, in the present embodiment, the incident point SR of the red laser beam having the smallest total beam number is smallest, and the incident point SB of the blue laser beam having the largest total beam number is largest.
Next, the emission of light from the vehicle headlamp 1 will be described. Specifically, a case where the low beam is emitted from the vehicle headlamp 1 will be described.
The red laser beam emitted upward from the first light source 52R is collimated by the collimator lens 53R and enters the first phase modulation element 54R at an entrance point SR of a predetermined size. The red laser beam is diffracted and reflected by the first phase modulation element 54R, and the first light DLR serving as a light distribution pattern of low beam is emitted forward.
The green laser beam emitted backward from the second light source 52G is collimated by the collimator lens 53G, and enters the second phase modulation element 54G at an entrance point SG larger than the entrance point SR. The green laser beam is diffracted and reflected by the second phase modulation element 54G, and the second light DLG serving as a light distribution pattern of a low beam is emitted upward.
The blue laser beam emitted backward from the third light source 52B is collimated by the collimator lens 53B, and enters the third phase modulation element 54B at an entrance point SB larger than the entrance point SG. The blue laser beam is diffracted and reflected by the third phase modulating element 54B, and the third light DLB, which is a light distribution pattern of a low beam, is emitted upward.
The first light DLR emitted from the first phase modulation element 54R passes through the first optical element 55f of the combining optical system 55 disposed in front of the first phase modulation element 54R. The second light DLG emitted from the second phase modulation element 54G is reflected by the first optical element 55f disposed above the second phase modulation element 54G, and is emitted forward from the first optical element 55 f. Thus, the first combined light LS1 composed of the lights DLR and DLG propagates forward.
The first combined light LS1 emitted from the first optical element 55f passes through the second optical element 55s of the combining optical system 55 arranged in front of the first optical element 55 f. The third light DLB emitted from the third phase modulating element 54B is reflected by the second optical element 55s disposed above the third phase modulating element 54B, and is emitted forward from the second optical element 55 s. Thus, the second combined light LS2 composed of the lights DLR, DLG, and DLB is emitted forward from the second optical element 55 s.
As described above, the lights DLR, DLG, and DLB forming the second combined light each have a light distribution pattern of low beam. Therefore, the second combined light LS2 emitted from the opening 40H propagates forward by a predetermined distance, and the lights DLR, DLG, and DLB overlap with each other, thereby forming low beam PL that is white light as shown in fig. 30.
As described above, according to the vehicle headlamp 1 of the present embodiment, the incident point SB of the blue laser beam having the largest total number of beams is the largest, and the incident point SR of the red laser beam having the smallest total number of beams is the smallest. Therefore, the energy per unit area of the red laser beam incident on the phase modulation element 54R, the energy per unit area of the green laser beam incident on the phase modulation element 54G, and the energy per unit area of the blue laser beam incident on the phase modulation element 54B can be equally approximated. Therefore, it is possible to suppress the deterioration of a specific phase modulation element more quickly than other phase modulation elements, and to suppress the destruction of the light distribution pattern over a long period of time. Therefore, the durability of the vehicle headlamp can be suppressed from being shortened.
In this way, by varying the size of the incident point of each laser beam according to the total number of beams and not providing an optical system for adjusting the size of the incident point, the energy per unit area of each laser beam can be equalized, and an increase in the number of components can be suppressed.
(fourth embodiment)
Next, a fourth embodiment of the present invention will be explained. Note that the same or equivalent constituent elements as those of the first embodiment are denoted by the same reference numerals and redundant description thereof is omitted except for the case of special description.
The lamp unit 20 of the vehicle headlamp 1 according to the fourth embodiment of the present invention is different from the lamp unit 20 according to the first embodiment in that three first light sources 52R, two second light sources 52G, and one third light source 52B are provided, and one light source 52R, 52G, and 52B is provided.
Although the light sources 52R, 52G, and 52B of the present embodiment can be recognized as fig. 27 in the vertical section, three first light sources 52R are arranged along the depth direction perpendicular to the front-back direction and the vertical direction, two second light sources 52G are arranged along the depth direction above the three first light sources 52R, and one third light source 52B is arranged above the two second light sources 52G. In the present embodiment, the total luminous flux amounts of the lights emitted from the plurality of light sources are substantially the same.
In order to improve the luminance and white balance of white light, it is preferable to maximize the total light flux of red light and minimize the total light flux of blue light, among red light, green light, and blue light, for example. Therefore, in the lamp unit 20 of the present embodiment, as described above, the three first light sources 52R that emit red light are arranged so that the total light flux of red light is maximized, the two second light sources 52G that emit green light are arranged so that the total light flux of green light is smaller than the total light flux of red light, and the one third light source 52B that emits blue light is arranged so that the total light flux of blue light is minimized.
Fig. 34 is a front view of the phase modulation element according to the present embodiment shown together with the incident point of light incident on the phase modulation element at the same angle of view as in fig. 28. As shown in fig. 34, in the present embodiment, the number of the first light sources 52R is three, and the incidence point SR of red light emitted from the first light sources 52R is smaller than each of the two incidence points SG of green light and the one incidence point SB of blue light. Further, incident point SG of green light emitted from the two second light sources 52G is smaller than incident point SR. The number of the third light sources 52B is one, and the incident point SB of the blue light emitted from the third light sources 52B is the largest. As described above, in the present embodiment, the smaller the incident point, the more light sources are emitted.
Therefore, the red light emitted from the plurality of light sources 52R can be received without leakage, without making the first phase modulation element 54R larger than the other phase modulation elements 54G and 54B.
As described above, since the smaller the incident point is, the more the light is emitted from the light sources, the light emitted from the plurality of light sources by the phase modulation element can be received without leakage while suppressing the increase in size of the phase modulation element without providing an optical system or the like for adjusting the size of the incident point, and the increase in the number of components can be suppressed.
In the present embodiment, an example in which the number (three) of the first light sources 52R is the largest and the number (one) of the third light sources 52B is the smallest has been described, and of at least two lights having different incident point sizes, the smaller the incident point is, the more light sources are emitted.
The present invention has been described above by taking the first to fourth embodiments as examples, but the present invention is not limited to these embodiments.
For example, in the first and second embodiments, the description has been given of an example in which the incident point of the phase modulation element is smaller for a laser beam having a longer optical path length to the phase modulation element, but the present invention is not limited thereto. For example, as in the third embodiment, the incident point of the phase modulation element may be increased for a laser beam having a larger total beam number. In this case, as in the third embodiment, the energy per unit area of the red laser beam incident on the phase modulation element 54R, the energy per unit area of the green laser beam incident on the phase modulation element 54G, and the energy per unit area of the blue laser beam incident on the phase modulation element 54B can be made nearly the same. Therefore, it is possible to suppress deterioration and the like of a specific phase modulation element earlier than other phase modulation elements.
In the third embodiment, an example in which the incident point of the phase modulation element is larger for the laser beam having the larger total beam number is described, but the present invention is not limited to this. For example, as in the first and second embodiments, the incident point of the phase modulation element may be made smaller for a laser beam having a longer optical path length to the phase modulation element. In this case, in the vehicle headlamp 1 according to the third embodiment, a desired light distribution pattern can be easily obtained.
In the first to fourth embodiments, the description has been given of the example in which the incident point SR of red light emitted from the first light source 52R, the incident point SG of green light emitted from the second light source 52G, and the incident point SB of blue light emitted from the third light source 52B are different from each other, but at least two of the incident points SR, SG, SB may be different in size. When the incident points SR, SG, and SB are all different in size, the size of the spot diameter can be more effectively adjusted, and the increase in the number of components can be more effectively suppressed.
Further, considering the case where the incident points SR, SG, and SB are all different in size, for example, light having a longer wavelength tends to be refracted more, and the incident point of light having a longer wavelength may be made smaller. For example, as shown in fig. 35, the size of the dots is increased in the order of the incident point SR of red light having the longest wavelength, the incident point SG of green light having a shorter wavelength than red light, and the incident point SB of blue light having the shortest wavelength, and these incident points SR, SG, and SB are concentric circles. The red light, the green light, and the blue light are refracted by the phase modulation element 54S, and then reflected by the phase modulation element 54S to be emitted from the phase modulation element 54S. As described above, since light having a longer wavelength tends to be refracted more greatly, red light emitted from the phase modulation element 54S is refracted most in the phase modulation element 54S, and blue light emitted from the phase modulation element 54S is refracted least in the phase modulation element 54S. Here, as described above, since the incident point SR among the incident points SR, SG, SB that are concentric circles is the smallest and the incident point SB is the largest, the red light, the green light, and the blue light emitted from the phase modulation element 54S travel a predetermined distance, the respective outer edges of the red light, the green light, and the blue light overlap, and the occurrence of color bleeding in the outer edge of the combined light composed of the red light, the green light, and the blue light is suppressed.
In the first to fourth embodiments, the description has been given of an example using a reflective LCOS as the phase modulation element, but other types of phase modulation elements may be used as the phase modulation element. For example, a transmissive LCOS may be used, a diffraction grating may be used, or glv (scattering Light valve) may be used. GLV is a reflective phase modulation element having a silicon substrate on which a plurality of reflectors are provided, and different diffraction patterns can be formed by electrically controlling the deflection of the plurality of reflectors. In addition, when the phase modulation element is an LCOS, the phase modulation pattern can be appropriately changed by adjusting the voltage applied to the phase modulation element. Further, by using the LCOS as the phase modulation element, it is possible to form a predetermined light distribution pattern by causing different lights to enter a common phase modulation element as in the second embodiment.
In the first to fourth embodiments, the vehicle headlamp 1 serving as a vehicle lamp irradiates the low beam PL, but the present invention is not particularly limited thereto. For example, the vehicle lamp according to the other embodiment may be configured to irradiate light having a lower intensity than the low beam PL in a region indicated by a broken line in fig. 30, that is, a region above the region irradiated with the low beam PL. Such low intensity light is, for example, optical OHS for identification. In this case, it is preferable that the light emitted from each of the phase modulation elements 54R, 54G, and 54B include light OHS for identification. In such an embodiment, it can be understood that a light distribution pattern for night illumination is formed by the low beam PL and the marker recognition light OHS. The term "night" as used herein is not limited to "night" and includes dark places such as tunnels. In addition, the vehicle lamp according to another embodiment may be configured to emit the high beam PH shown in fig. 36. In fig. 36, the light distribution pattern of the high beam PH is indicated by a thick line, and the straight line S indicates a horizontal line. In the light distribution pattern of the high beam PH, the region PHA1 is a region with a strong light intensity, and the region PHA2 is a region with a lower light intensity than the region PHA 1. In still another embodiment, the vehicle lamp according to the present invention may be applied to a configuration of an image. In this case, the direction of light emitted from the vehicle lamp and the mounting position of the vehicle lamp of the vehicle are not particularly limited.
Industrial applicability
The present invention provides a vehicle lamp that can be used in the field of automobiles and the like, and that can suppress an increase in the number of components.

Claims (30)

1. A lamp for a vehicle, characterized by comprising:
a light source for emitting light of a predetermined wavelength;
a phase modulation element for diffracting the light emitted from the light source to form the light into a predetermined light distribution pattern;
a point moving unit that relatively moves an incident point of the light on the phase modulation element with respect to the phase modulation element;
the phase modulation element is divided into modulation sections that form the light distribution pattern, and at least one of the modulation sections is included in the incident point.
2. A lamp for a vehicle as defined in claim 1,
the distance of relative movement of the incident point is more than the radius of the incident point.
3. A lamp for a vehicle as claimed in claim 2,
the distance is greater than the diameter of the incident point.
4. A lamp for a vehicle as claimed in any one of claims 1 to 3,
the point of incidence is periodically moved relative to each other.
5. A lamp for a vehicle as claimed in any one of claims 1 to 4,
the point moving unit relatively moves the incident point in two or more directions.
6. A lamp for a vehicle as claimed in any one of claims 1 to 5,
the phase modulation element is LCOS.
7. A lamp for a vehicle as claimed in any one of claims 1 to 6,
the point moving section moves the light source.
8. A lamp for a vehicle as recited in claim 7,
the light source is provided with a circuit board for supplying power to the light source, and the light source moves relative to the circuit board.
9. A lamp for a vehicle as recited in claim 8,
the circuit substrate includes an elastic connection portion electrically connected to the light source.
10. A lamp for a vehicle as claimed in any one of claims 1 to 9,
the phase modulation element is provided on each of the plurality of light sources.
11. A lamp for a vehicle as claimed in any one of claims 1 to 9,
the phase modulation element includes a plurality of light sources that emit light having different wavelengths from each other, at least two of the plurality of light sources switch emission of the light at a predetermined cycle, and the plurality of light emitted from the at least two light sources are incident on the common phase modulation element.
12. A lamp for a vehicle, characterized by comprising:
a light source that emits light;
a phase modulation element having a plurality of modulation units that diffract the light from the light source to form a predetermined light distribution pattern;
the width of the incident surface of the phase modulation element on which the light is incident in the vertical direction is larger than the width of the incident surface in the horizontal direction,
the size of the incident point of the light of the phase modulation element is a size capable of containing at least one of the modulation sections,
at least a part of the plurality of modulation units are arranged in the vertical direction.
13. A lamp for a vehicle as defined in claim 12,
the point of incidence is in the shape of a long strip that is long in a particular direction compared to other directions,
the specific direction is not parallel to the horizontal direction.
14. A lamp for a vehicle as defined in claim 12,
the point of incidence is in the shape of a long strip that is long in a particular direction compared to other directions,
the specific direction is not parallel to the vertical direction.
15. A lamp for a vehicle as claimed in any one of claims 12 to 14,
the plurality of modulation units are arranged in the vertical direction and the horizontal direction, and the number of modulation units arranged in the vertical direction is larger than the number of modulation units arranged in the horizontal direction.
16. A lamp for a vehicle as claimed in any one of claims 12 to 15,
a plurality of said light sources are provided,
said phase modulating element being disposed on said each of a plurality of said light sources,
the width in the vertical direction of the incident point of the phase modulation element having the largest optical path length of the corresponding light source among the plurality of phase modulation elements is equal to or less than the largest width among the widths in the vertical direction of the incident points of the other phase modulation elements.
17. A lamp for a vehicle as claimed in any one of claims 12 to 15,
a plurality of said light sources are provided,
said phase modulating element being disposed on said each of a plurality of said light sources,
at least one of the phase modulation elements is connected to at least one other of the phase modulation elements and is formed integrally with the other phase modulation element.
18. A lamp for a vehicle, characterized by comprising:
a light source for emitting light;
a phase modulation element having at least one modulation section for diffracting the light from the light source to form a predetermined light distribution pattern;
an incident surface of the phase modulation element on which the light is incident and an incident point of the light on the phase modulation element are elongated in a predetermined direction as compared with other directions,
the size of the incidence point is the size capable of containing at least one modulation part,
the long side direction of the incident surface of the phase modulation element is not perpendicular to the long side direction of the incident point.
19. A vehicle lamp as set forth in claim 18,
the long side direction of the incident surface of the phase modulation element is parallel to the long side direction of the incident point.
20. A vehicular lamp according to claim 18 or 19,
the long side direction of the incident surface of the phase modulation element is a horizontal direction.
21. A vehicular lamp according to any one of claims 18 to 20,
a plurality of said light sources are provided,
the phase modulation element is disposed on each of a plurality of the light sources,
at least one of the phase modulation elements is connected to at least one other of the phase modulation elements and is formed integrally with the other phase modulation element.
22. A vehicular lamp according to any one of claims 18 to 20,
a plurality of said light sources are provided,
the phase modulation element is provided on each of the plurality of light sources,
at least two of the phase modulating elements are juxtaposed adjacently in a specific direction,
the long side direction of each of the incident surfaces of the at least two phase modulation elements is parallel to the specific direction.
23. A lamp for a vehicle, characterized by comprising:
a plurality of light sources that emit light having different wavelengths from each other;
at least one phase modulation element for diffracting the light emitted from each of the plurality of light sources to form a predetermined light distribution pattern for each of the plurality of lights;
sizes of incident points of the phase modulation elements of at least two of the lights different in wavelength are different from each other.
24. A vehicle lamp as set forth in claim 23,
the size of the incident point of the plurality of the lights is different.
25. A lamp for a vehicle as claimed in claim 23 or 24,
at least two of the lights are incident on the common phase modulation element.
26. A lamp for a vehicle as claimed in any one of claims 23 to 25,
the phase modulation element is LCOS.
27. A lamp for a vehicle as claimed in any one of claims 23 to 26,
of at least two of the lights having the incident points of different sizes from each other, the more the light having the larger total number of beams, the larger the incident point.
28. A lamp for a vehicle as claimed in any one of claims 23 to 26,
of at least two of the lights having the incident points different in size from each other, the light having the longer optical path length to the phase modulation element is smaller in the incident point.
29. A lamp for a vehicle as claimed in any one of claims 23 to 26,
of at least two of the lights having the incident points different in size from each other, the smaller the incident point, the more the light is emitted from the light source.
30. A vehicular lamp according to any one of claims 24 to 26,
the longer the wavelength the smaller the point of incidence of the light.
CN201910924095.9A 2018-09-26 2019-09-23 Vehicle lamp Active CN110953542B (en)

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