CN113606551B - Lamp for vehicle - Google Patents

Lamp for vehicle Download PDF

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Publication number
CN113606551B
CN113606551B CN202110959769.6A CN202110959769A CN113606551B CN 113606551 B CN113606551 B CN 113606551B CN 202110959769 A CN202110959769 A CN 202110959769A CN 113606551 B CN113606551 B CN 113606551B
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CN
China
Prior art keywords
light
phase modulation
modulation element
incident
emitted
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Active
Application number
CN202110959769.6A
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Chinese (zh)
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CN113606551A (en
Inventor
鬼头壮宜
本桥和也
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Koito Manufacturing Co Ltd
Original Assignee
Koito Manufacturing Co Ltd
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Publication date
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Priority to CN202110959769.6A priority Critical patent/CN113606551B/en
Publication of CN113606551A publication Critical patent/CN113606551A/en
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Classifications

    • 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
    • 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
    • F21S41/20—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

Abstract

The invention provides a vehicle lamp which can easily obtain a desired light distribution pattern. A vehicle headlamp (1) as a vehicle lamp is provided with: 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 thereby form light into a predetermined light distribution pattern; and movable members (57R, 57G, 57B) for moving the incidence points of the light of the phase modulation elements (54R, 54G, 54B) relative to the phase modulation elements (54R, 54G, 54B). The phase modulation elements (54R, 54G, 54B) are divided into modulation sections (MP) that form a light distribution pattern. At least one modulation section (MP) is included in the incidence point.

Description

Lamp for vehicle
The application is a divisional application of an application patent application with the application date of 2019, 9, 23, the application number of 201910924095.9 and the application name of '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 as a vehicle lamp typified by an automotive headlamp. For example, patent document 1 describes that a predetermined light distribution pattern is formed using a hologram element, which is one type of phase modulation element.
In a vehicle lamp represented by a headlight for an automobile, various configurations have been studied in order to set a light distribution pattern of emitted light to a predetermined light distribution pattern. For example, in patent document 1 below, a predetermined light distribution pattern is formed by using a hologram element as one type of phase modulation element.
The vehicle lamp described in patent document 1 includes a hologram element and a light source for irradiating reference light to the hologram element. The hologram element performs calculation so that diffracted light reproduced by irradiation with 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 reference light to the hologram element. 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 forming a desired light distribution pattern by emitted light are discussed with respect to a vehicle headlamp as a vehicle lamp typified by an automotive headlamp. For example, patent document 1 describes that a predetermined light distribution pattern is formed by a hologram element, which is one of phase modulation elements.
Patent document 1 (Japanese patent application laid-open No. 2012-146621)
However, in the phase modulation element described in patent document 1, when light is concentrated and incident on a specific region, the region is heated to change the characteristics of the phase modulation element, and a desired light distribution pattern may not be formed.
Here, the vehicle vibrates due to the road surface condition 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 to the hologram element vibrates with respect to the hologram element due to the 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 be formed even if vibration occurs. In response to this demand, it is considered that the entire hologram element is irradiated with the reference light even if the incident point of the reference light increases and vibration occurs. However, in this case, since a part of the reference light does not strike the hologram element, the energy efficiency is lowered.
In patent document 1, a semiconductor laser is used as a light source, for example. Since the laser beam emitted from the semiconductor laser propagates while expanding in a substantially elliptical shape, when the laser beam is not adjusted in shape, the incident point of the laser beam is a substantially elliptical shape elongated in a specific direction. On the other hand, the hologram element is substantially rectangular as described above, and is different from the shape of the incident point of the laser light. Therefore, when the laser light emitted from the semiconductor laser beam is incident on the entire hologram element, a part of the laser light emitted from the semiconductor laser beam is not irradiated on the hologram element, and thus the energy efficiency is required to be reduced. For this requirement, for example, the shape of the incident point is adjusted to a shape corresponding to the shape of the hologram element. However, in this case, since an optical element for adjusting the shape of the laser light is used, the vehicle lamp may be enlarged.
In the case of using the vehicle lamp described in patent document 1, it is considered to synthesize a desired color using a plurality of semiconductor lasers emitting laser beams having different wavelengths. However, when a plurality of semiconductor lasers are used, the distances from each semiconductor laser to the phase modulation element forming a desired light distribution pattern may be different. In general, the diameters of laser beams emitted from a plurality of semiconductor laser elements with different wavelengths tend to be different from each other. In this case, it is considered to align the dot diameters of the laser light incident on the phase modulation element using a lens or a mask, but this leads to an increase in the number of components.
Disclosure of Invention
A first object of the present invention is to provide a vehicle lamp in which a desired light distribution pattern is easily obtained.
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 that can suppress an increase in size.
A fourth object of the present invention is to provide a vehicle lamp capable of suppressing an increase in the number of components.
In order to achieve the first object, a vehicle lamp according to the present invention includes: a light source that emits light of a predetermined wavelength; a phase modulation element configured to diffract the light emitted from the light source to thereby form a predetermined light distribution pattern; a point moving unit for moving the incident point of the light of the phase modulation element relative to the phase modulation element; the phase modulation element is divided into modulation sections forming 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 incidence point, the same light distribution pattern can be formed even when the position of the incidence point is shifted. In addition, with this vehicle lamp, since the incidence point moves relative to the phase modulation element, it is possible to suppress concentrated incidence of light in a specific region of the phase modulation element, and it is possible to suppress the specific region from becoming high temperature. Therefore, the generation of a region where it is difficult to form a predetermined light distribution pattern is suppressed, and a desired light distribution pattern is easily obtained.
The distance by which the incident point is moved relative to each other is preferably equal to or greater than the radius of the incident point.
The power distribution of the light at the incidence point is generally different, and for example, a predetermined region such as a center region of the incidence point tends to be a peak region of the power. When the size of the peak region is considered, if the distance of the 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 overlapping of the peak regions can be suppressed before and after the relative movement, and the increase in temperature of the specific region of the phase modulation element can be effectively suppressed.
In the case where the distance by which the incident point moves relative to each 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 portion of the incident point after the relative movement is suppressed from overlapping with the portion of the incident point before the relative movement, the specific region of the phase modulation element can be more effectively suppressed from being heated.
The incidence points may be periodically moved relative to each other.
In this case, since the incidence points are periodically moved relatively, it is possible to further suppress incidence of light in a specific region of the phase modulation element for a long period of time. Therefore, the temperature rise 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 moved relatively over a wider range than in the case where the incident point is moved relatively in only one direction. Therefore, the temperature rise in the specific region of the phase modulation element can be effectively suppressed.
The phase modulation element may be LCOS (Liquid Crystal On Silicon: liquid crystal on silicon).
LCOS is a phase modulation element that generates a reflectance difference in a liquid crystal layer by changing an alignment pattern of liquid crystal molecules. In such LCOS, when the temperature of a specific region increases, a change in the alignment pattern in the region increases, and thus it is difficult to obtain a desired light distribution pattern. However, as described above, since the light is suppressed from being concentrated in a specific region, a desired light distribution pattern is easily obtained even in the case where the phase modulation element is an LCOS.
The point moving unit may move the light source.
The light source tends to be lighter than 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.
As described above, when the point moving unit moves the light source, the light source may be moved relative to the circuit board, and the circuit board may be provided with power to supply the light source.
In this case, only the light source can be moved without moving the circuit board.
In the case where the point moving unit moves the light source as described above, the circuit board may include an elastic connection unit electrically connected to the light source.
Thereby, the light source can move relative to the circuit board.
The vehicle lamp may have a plurality of light sources that emit light having different wavelengths, and the phase modulation element may be provided for each of the plurality of light sources.
By providing a plurality of light sources emitting light having different wavelengths, light of a desired color can be generated. In addition, by providing the phase modulation element for each of the plurality of light sources, the light distribution pattern can be easily adjusted for each light source.
The phase modulation element may be configured to emit light having a plurality of wavelengths different from each other, and at least two of the plurality of light sources may be configured to switch emission of the light at a predetermined period.
By providing a plurality of light sources emitting light having different wavelengths, light of a desired color can be generated. In addition, by making the phase modulation elements that receive light from at least two light sources common, the number of phase modulation elements provided in the vehicle lamp can be reduced, and the number of components and the cost can be reduced.
ADVANTAGEOUS EFFECTS OF INVENTION
The vehicle lamp according to the present invention described above can be used to provide a vehicle lamp that can easily obtain a desired light distribution pattern.
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 sections that diffract the light from the light source to form the light into a predetermined light distribution pattern; the incident surface of the phase modulation element on which the light is incident has a width in a vertical direction larger than a width of the incident surface in a horizontal direction, and the incident point of the phase modulation element is sized to include at least one modulation unit, and at least a part of the plurality of modulation units are juxtaposed in the vertical direction.
The vehicle lamp also vibrates in the same manner as the vehicle, because the vehicle has a tendency to vibrate with a greater amplitude in the vertical direction than in the horizontal direction. Therefore, the incident point of the light to 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 vibration of the vehicle, the vehicle lamp can suppress exposure of a part of the incident point from the incident surface of the phase modulation element, and can suppress a reduction in energy efficiency. In this vehicle lamp, as described above, the size of the incident point is such that at least one modulation unit can be included, and at least a part of the plurality of modulation units are juxtaposed in the vertical direction. Therefore, in this vehicle lamp, even when the incident point vibrates in the vertical direction due to vibration of the vehicle, a predetermined light distribution pattern can be formed because light can be incident on any one of the modulation portions.
The incidence point may have a long strip shape longer in a specific direction than in other directions, and the specific direction may not be 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, the width of the phase modulation element in the horizontal direction can be reduced as compared with the case where the specific direction is parallel to the horizontal direction, and the manufacturing cost of the vehicle lamp can be reduced.
Alternatively, the incident point may have a long shape in a specific direction, which is not parallel to the vertical direction, compared to other directions.
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 with the case where the specific direction is parallel to the vertical direction, when the incident point vibrates in the vertical direction due to the vibration of the vehicle, it is possible to suppress a part of the incident point from being exposed from the incident surface of the phase modulation element.
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, when the incident point vibrates in the vertical direction due to vibration of the vehicle, light from the light source is easily incident on any of the modulation sections, as compared with the case where the number of modulation sections juxtaposed in the vertical direction is smaller than the number of modulation sections juxtaposed in the horizontal direction.
The vehicle lamp may further include a plurality of light sources, wherein the phase modulation element is provided for each of the plurality of light sources, and a width of the incident point of the phase modulation element having a largest optical path length among the plurality of phase modulation elements in the vertical direction is equal to or smaller than a maximum width of the incident points of the other phase modulation elements in the vertical direction.
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, which is easily increased with respect to the amplitude of the vibration of the phase modulation element, is equal to or less than the maximum width of 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 of the phase modulation element and the light source are not adjusted, it is possible to suppress that a part of the incident point of the phase modulation element, in which the amplitude of the vibration of the incident point with respect to the phase modulation element is easily increased, is exposed from the incident surface of the phase modulation element. Therefore, the size of the phase modulation element and the degree of freedom in arrangement of the phase modulation element with respect to the light source can be improved.
The light source may be a plurality of light sources, the phase modulation element may be provided on each of the plurality of 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, at least two phase modulation elements are integrally formed, so that 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 unit configured to diffract the 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 elongated in a predetermined direction compared with other directions, the incident point is sized to include at least one modulation unit, and the longitudinal direction of the incident surface of the phase modulation element is not perpendicular to the longitudinal direction of the incident point.
In this vehicle lamp, since light from the light source is incident on at least one modulation unit, a predetermined light distribution pattern can be formed by the modulation unit 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, the vehicle lamp can suppress exposure of a part of the incident point from the phase modulation element without adjusting the shape of the light from the light source, compared 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. Therefore, the vehicle lamp can suppress a decrease in energy efficiency and an increase in size.
The longitudinal direction of the incident surface of the phase modulation element may be parallel to the longitudinal direction of the incident point.
With such a configuration, even if the shape of the laser beam is not adjusted, it is possible to further suppress exposure of a part of the incident point from the phase modulation element.
The longitudinal direction of the incident surface of the phase modulation element may be a horizontal direction.
There may be a plurality of the light sources, and the phase modulation element may be provided on each of the plurality of the 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, at least two phase modulation elements are integrally formed, so that the number of components can be reduced.
The light source may further include a plurality of light sources, the phase modulation element may be provided on each of the plurality of light sources, at least two of the phase modulation elements may be arranged adjacently and in parallel 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, at least two phase modulation elements are arranged adjacently in a specific direction as described above. For this reason, for example, from the viewpoint of simply configuring the vehicle lamp, a plurality of light sources corresponding to a plurality of adjacent phase modulation elements may be juxtaposed. In this case, even if a light guide optical system that guides the incident light to a desired position by reflecting the light is not used, the light from the light source can be made incident on the phase modulation element. In this vehicle lamp, as described above, the longitudinal direction of each of the incident surfaces of the adjacent parallel 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 the case where the longitudinal direction of each of the adjacent phase modulation elements is perpendicular to the specific direction. Therefore, even in the case where the plurality of light sources are arranged in parallel as described above, the distance between the adjacent light sources can be increased as compared with the case where the longitudinal direction of each of the incident surfaces of the plurality of phase modulation elements arranged adjacently is perpendicular to the specific direction. Therefore, 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, as compared with a case where the longitudinal direction of each of the incident surfaces of the plurality of phase modulation elements arranged adjacently is perpendicular to the specific direction.
ADVANTAGEOUS EFFECTS OF INVENTION
The present invention provides a vehicle lamp that can suppress a decrease in energy efficiency and can suppress 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 emitting 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 light sources; the magnitudes of the incident points of the phase modulation elements of at least two of the lights having different wavelengths are different from each other.
With this vehicular lamp, the size of the incident point of light having different wavelengths incident on the phase modulation element is allowed to be different. Therefore, an optical member or the like for adjusting the size of the incident point of light having different wavelengths can be omitted, and an increase in the number of members can be suppressed.
In addition, the incident points of the light may be different in size.
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 light incident on the common phase modulation element, the number of phase modulation elements can be reduced.
The phase modulation element may be LCOS (Liquid Crystal On Silicon: liquid crystal on silicon).
In this way, by making the phase modulation element LCOS, the phase modulation pattern of the phase modulation element can be appropriately changed. In addition, different light is made incident on the common phase modulation element, and a predetermined light distribution pattern can be formed.
Further, the larger the total number of light beams, the larger the incidence point may be, among at least two lights having different incidence points.
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 degradation of a specific phase modulation element earlier than other phase modulation elements.
In addition, the longer the optical path length to the phase modulation element, the smaller the incidence point may be, among at least two lights having different magnitudes of the incidence points.
The longer the optical path length to the phase modulation element, the more the amount of movement of the point of the phase modulation element tends to increase when the light source is rocked. Therefore, the longer the optical path length to the phase modulation element is, the smaller the dot diameter is, and the dot diameter can be suppressed from being exposed from the phase modulation element when the light source is rocked.
In addition, the light having a smaller incidence point may be emitted from more of the light sources among at least two lights having different incidence points.
In this case, even if the phase modulation element that receives light emitted from more light sources is not larger than the other phase modulation elements, light emitted from the many light sources can be received without leakage.
In addition, when the sizes of the incident points of the plurality of lights are different, the incident point of the light having a longer wavelength may be made smaller.
In this case, color permeation of light can be suppressed.
ADVANTAGEOUS EFFECTS OF INVENTION
With the vehicle lamp according to the present invention as described above, there is provided a vehicle lamp capable of suppressing an increase in the number of components.
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 schematic diagram 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 beam.
Fig. 7 is a view showing a lamp unit of a vehicle lamp according to a second embodiment of the present invention, similar 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, similar to fig. 2.
Fig. 9 is a diagram showing a light distribution pattern of high beam.
(Second aspect)
Fig. 10 is a schematic view of 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 diagram 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, similar 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 schematic view of 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 diagram 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, similar to fig. 18.
Fig. 25 is a view showing an optical system unit according to a fourth embodiment of the present invention, similar 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 portion 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 the incidence point of light incident on the phase modulation element.
Fig. 29 is a diagram 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 diagram showing a light distribution pattern of low beam.
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 the incidence 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 at the same angle as fig. 28, together with the point of incidence of light to the phase modulation element.
Fig. 35 is a view showing another example using the phase modulation element shown in fig. 31 at the same angle as fig. 32.
Fig. 36 is a diagram showing a light distribution pattern of high beam.
Description of the reference numerals
(First aspect)
1. Front shining lamp for vehicle (Lamp for vehicle)
20. Lamp 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 movement part)
59R, 59G, 59B circuit board
93. Elastic connecting part
157R, 157G elastic member
MP modulation unit
(Second aspect)
1. Front shining lamp (vehicle lamp)
10. Frame body
20. Lamp 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 guiding optical system
EF, EFR, EFG, EFB entrance face
LAR, LAG, LAB major axis
MPR, MPG, MPB modulation unit
SR, SG, SB incidence point
H54 Width of longitudinal direction of phase modulation element
Width of WR first phase modulation element in transverse direction
Transverse width of WG second phase modulating element
Transverse width of WB third phase modulation element
Width of WS phase modulation element in transverse direction
(Third aspect)
1. Front shining lamp (vehicle lamp)
10. Frame body
20. Lamp 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 guiding optical system
EF, EFR, EFG, EFB entrance face
LAR, LAG, LAB major axis
MPR, MPG, MPB modulation unit
SR, SG, SB incidence point
(Fourth aspect)
1. Front shining lamp for vehicle (Lamp for vehicle)
20. Lamp 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 guiding optical system
SR, SG, SB incidence point
Detailed Description
(First aspect)
Hereinafter, a mode for implementing the vehicle lamp of the present invention is exemplified together with 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 gist thereof. In the drawings referred to below, the dimensions of the respective components may be changed for easy understanding.
(First embodiment)
Fig. 1 is a diagram illustrating an example of a vehicle lamp according to the present embodiment, and is a vertical cross-sectional view schematically illustrating a cross-section of the vehicle lamp in the up-down direction. In the present embodiment, the vehicle lamp is a vehicle headlamp 1. As shown in fig. 1, the vehicle headlamp 1 has a housing 10 and a lamp unit 20 as main configurations.
The housing 10 has a lamp housing 11, a front cover 12, and a rear cover 13 as main structures. The front opening of the lamp housing 11 is opened, 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.
The space formed by the lamp housing 11, the front cover 12 closing the front opening of the lamp housing 11, and the rear cover 13 closing the rear opening of the lamp housing 11 is a lamp room R, and the lamp unit 20 is housed in the lamp room 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 radiator 30 has a metal bottom plate 31 extending substantially in the front-rear direction, and a plurality of radiating fins 32 are integrally provided 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 radiating fins 32, and is fixed to the heat sink 30. The radiator 30 is cooled by the air flow generated by the rotation of the cooling fan 35. A case 40 is disposed on the upper surface of the bottom plate 31 of the radiator 30.
The case 40 of the present embodiment includes a base 41 made of metal such as aluminum, for example, and a cover 42, and the base 41 is fixed to the upper surface of the bottom plate 31 of the radiator 30. The base 41 is formed in a box shape having an opening formed from the front across the upper portion, and the cover 42 is fixed to the base 41 so as to include an opening on the upper portion side. An opening 40H defined by the front end of the base 41 and the front end of the cover 42 is formed in the front portion of the housing 40. An optical system unit 50 is disposed in the space inside the housing 40. The inner walls of the base 41 and the cover 42 are preferably light-absorbing due to black alumina film processing or the like. By making the inner walls of the base 41 and the cover 42 light-absorbing, accidental reflection or reflection of light irradiated to the inner wall of the base 41 by reflection or the like can be suppressed, and the light can be emitted from the opening 40H in an accidental direction.
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 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 as main configurations. In the present embodiment, the phase modulation elements 54R, 54G, and 54B are reflective phase modulation elements that diffract incident light while reflecting the light, and specifically, reflective LCOS (Liquid Crystal On Silicon: liquid crystal on silicon).
The first light source 52R is a laser device that emits laser light of a predetermined wavelength, and in the present embodiment, the peak wavelength of power emits red laser light of 638nm upward, for example. The second light source 52G and the third light source 52B are laser elements that emit laser light of a predetermined wavelength, respectively, and in the present embodiment, the second light source 52G emits green laser light of a peak wavelength of power of, for example, 515nm rearward, and the third light source 52B emits blue laser light of a peak wavelength of power of, for example, 445nm rearward.
The first light source 52R is fixed to a movable portion of a movable member 57R fixed to the base 41. The movable part of the movable member 57R is connected to a control unit, not shown, and is periodically moved in both the front-rear direction and the depth direction perpendicular to the front-rear direction and the up-down direction by control of the control unit. The second light source 52G is fixed to a movable portion of the movable member 57G fixed to the base 41. The movable part of the movable member 57G is connected to a control part, not shown, and is periodically moved in the up-down direction and the depth direction by the control of the control part. The third light source 52B is fixed to a movable portion of the movable member 57B fixed to the base 41. The movable part of the movable member 57B is connected to a control part, not shown, and is periodically moved in the up-down direction and the depth direction under the control of the control part.
The first light source 52R is electrically connected to the 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 the 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 the circuit board 59B fixed to the base 41, and receives power supply via the circuit board 59B.
The circuit boards 59R, 59G, 59B have elastic connection portions for movably holding the light sources, respectively. 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 structure 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 interposed therebetween. These conductive layers 94 are electrically connected via the 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 connection portions 93 located inside the circular hole 90. The flat plate portion 92 located on one side of the circular hole 90 is fixed to the conductive layer 94 located 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 are formed as 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 terminals of the light source 52R are fitted inside the circle formed by the elastic connection portion 93, so that the light source 52R is electrically connected to the elastic connection portion 93, and the light source 52R is movably held by the elastic connection portion 93. With this configuration, the light source 52R can also be moved 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 beam 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 beam 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 beam emitted from the third light source 52B. These collimator lenses 53R, 53G, 53B are fixed to the housing 40 by a structure not shown.
The fast axis direction and the slow axis direction of the laser light may be collimated by providing a collimator lens for collimating the fast axis direction of the laser light and a collimator lens for collimating the slow axis direction of the laser light, respectively.
The first phase modulation element 54R is disposed above the first collimating lens 53R, and is fixed to the base 41 by a structure not shown. The first phase modulation element 54R is disposed to be inclined by about 45 ° with respect to the front-rear direction and the up-down direction. Therefore, the red laser light emitted from the first collimating lens 53R is incident on the first phase modulation element 54R, diffracted, and is converted to a direction of about 90 ° and emitted toward the front-located combining optical system 55.
The second phase modulation element 54G is disposed behind the second collimator lens 53G, and is fixed to the base 41 by a structure not shown. The second phase modulation element 54G is disposed so as to be inclined by 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. Accordingly, the green laser light emitted from the second collimator lens 53G is incident on the second phase modulation element 54G, diffracted, and emitted toward the upper combining optical system 55 while being converted to a direction of about 90 °.
The third phase modulation element 54B is disposed behind the third collimator lens 53B, and is fixed to the base 41 by a structure not shown. The third phase modulation element 54B is disposed so as to be inclined by 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. Accordingly, the blue laser light emitted from the third collimator lens 53B is incident on the third phase modulation element 54B, diffracted, and converted to a direction of about 90 ° and emitted to the upper combining optical system 55.
The combining optical system 55 includes a first optical element 55f and a second optical element 55s. 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 as to transmit light having a wavelength longer than a predetermined wavelength and reflect light having a wavelength shorter than the predetermined wavelength. In the present embodiment, the first optical element 55f transmits red light of 638nm wavelength emitted from the first light source 52R, and reflects green light of 515nm wavelength 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 of 638nm wavelength emitted from the first light source 52R and green light of 515nm wavelength emitted from the second light source 52G, and reflects blue light of 445nm wavelength emitted from the third light source 52B.
Next, the structures 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 be appropriately omitted.
Fig. 4 is a front view schematically showing the first phase modulating element 54R. As shown in fig. 4, the first phase modulation element 54R is formed in a substantially rectangular shape in a front view. The first phase modulation element 54R is divided into a plurality of modulation sections MP, and each modulation section MP includes a plurality of dots arranged in a matrix. A drive circuit 60R is electrically connected to the phase modulation element 54R. The drive circuit 60R has: 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 incidence point SR of the red laser light incident on the incidence surface of the first phase modulation element 54R. The incident point will be described in detail later.
Fig. 5 is a schematic diagram 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 silicon substrate 62, a drive circuit layer 63, a plurality of electrodes 64, a reflective film 65, a liquid crystal layer 66, a transparent electrode 67, and a light-transmitting substrate 68 as main structures.
The plurality of electrodes 64 are arranged in a matrix form in one-to-one correspondence with 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. 4 are arranged, and is arranged between the silicon substrate 62 and the plurality of electrodes 64. The light-transmitting substrate 68 is disposed opposite to the silicon substrate 62 on one side of the silicon substrate 62, and is, for example, a glass substrate. The transparent electrode 67 is disposed on the surface of the transparent 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 light emitted from the collimator lens 53R is incident from a surface of the light-transmitting substrate 68 opposite to the silicon substrate 62 side.
As shown in fig. 5, light RL incident from the surface of the light-transmitting substrate 68 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 light-transmitting substrate 68. When a voltage is applied between the 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. According to the change in alignment of the liquid crystal molecules 66a, the reflectance of the liquid crystal layer 66 located between the electrode 64 and the transparent electrode 67 changes, and the optical path length of the light RL transmitted through the liquid crystal layer 66 changes. Therefore, by transmitting the light RL through the liquid crystal layer 66 and emitting the light RL 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 point of each modulation section MP, the voltage applied between the electrode 64 and the transparent electrode 67 corresponding to each point is controlled, and the alignment of the liquid crystal molecules 66a is changed, so that the amount of change in the phase of the light emitted from each point can be adjusted according to each point. In the present embodiment, the same light distribution pattern is formed from each modulation section MP by adjusting the reflectance of the liquid crystal layer 66 at each point as described above.
Like 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 sections MP, and the modulation sections MP each include a plurality of dots arranged in a matrix. Therefore, the same light distribution pattern is formed from each modulation section MP by adjusting the reflectance of the liquid crystal layer 66 at each point.
In the present embodiment, the shape of the light distribution pattern formed by the phase modulation elements 54R, 54G, 54B is the same shape, specifically, the same shape as the light distribution pattern of the low beam.
Next, 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 source, 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 is periodically moved in the front-rear direction and the depth direction. Therefore, the red laser light 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 enters the phase modulation element 54R.
When power is supplied from a power source, 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 is periodically moved in the up-down direction and the depth direction. Therefore, the green laser light emitted from the second light source 52G also periodically moves in the up-down direction and the depth direction. Such green laser light is collimated by the second collimator lens 53G disposed at the rear side, and is incident on the phase modulator 54G.
When power is supplied from a power source, 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 is periodically moved in the up-down direction and the depth direction. Accordingly, the blue laser light emitted from the third light source 52B also periodically moves in the up-down direction and the depth direction. Such blue laser light is collimated by the third collimator lens 53B disposed at the rear side, and is incident on the phase modulator 54B.
The red laser light incident on the phase modulation element 54R is reflected by the phase modulation element 54R and is emitted from the phase modulation element 54R forward. As described above, the movable member 57R is periodically moved in both directions. Therefore, as shown in fig. 4, the incidence point SR of the red laser light periodically moves in two directions along the incidence plane 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. The solid circles in fig. 4 indicate the positions of the incident points SR before movement, and the four broken circles indicate the positions of the incident points SR after movement.
As shown in fig. 4, at least one modulation unit MP is provided at the incidence point SR, regardless of the position of the incidence point SR on the incidence surface of the phase modulation element 54R. Therefore, the light distribution pattern of the red laser light emitted from the phase modulation element 54R is the same regardless of the relative movement of the incident point SR, and the front and rear, and the relative movement. In this way, the red laser light having a 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 first light DLR. As described above, the shape of the light distribution pattern of first light DLR is the same shape as the light distribution pattern of 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 longer than the diameter of the incident point SR. In fig. 4, the incident point is shown as a circle, but the shape 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 is emitted upward from the phase modulation element 54G. As described above, the movable member 57G is periodically moved in both directions. Therefore, the incidence point of the green laser light periodically moves in two directions along the incidence plane 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 light with respect to the phase modulation element 54G.
Similarly to the incidence point SR of the red laser light, at least one modulation unit MP is included in the incidence point of the green laser light. Therefore, the light distribution pattern of the green laser light emitted from the phase modulation element 54G is the same regardless of the relative movement of the incident point of the green laser light, and the front and rear, and the relative movement. In this way, green light having a 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 second light DLG is the same shape as the light distribution pattern of low beam. In the present embodiment, the distance of movement of the incident point of the green laser light on the incident surface of the phase modulation element 54G is equal to or longer 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 is emitted upward from the phase modulation element 54B. As described above, the movable member 57B is periodically moved in both directions. Therefore, the incidence point of the blue laser light periodically moves in two directions along the incidence plane of the phase modulation element 54B. In this way, the movable member 57B functions as a point moving unit that moves the incidence point of the blue laser light with respect to the phase modulation element 54G.
Like the incident point SR of the red laser light, at least one modulation unit MP is included in the incident point of the blue laser light. Therefore, the light distribution pattern of the blue laser light emitted from the phase modulation element 54B is the same regardless of the relative movement of the incident point of the blue laser light, and the front and rear of the relative movement. In this way, blue light having a predetermined light distribution pattern is emitted upward from the phase modulation element 54B. Hereinafter, blue light emitted from phase modulation element 54B is referred to as third light DLB. As described above, the shape of the light distribution pattern of third light DLB is the same as the shape of the light distribution pattern of low beam. In the present embodiment, the distance of movement of the incident point of the blue laser light on the incident surface of the phase modulation element 54B is equal to or longer than the diameter of the incident point.
A first optical element 55f of the combining optical system 55 is arranged 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 55f. Further, a first optical element 55f is disposed above the second phase modulation element 54G. As described above, since 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 up-down direction, 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 arranged 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 55s. Further, a second optical element 55s is disposed above the third phase modulation element 54B. As described above, since 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 up-down direction, the third light DLB emitted from the third phase modulation 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.
The light DLR, DLG, DLB forming the second synthetic light each has a light distribution pattern in the shape of a low beam as described above. Accordingly, the second synthetic light LS2 emitted from the opening 40H propagates forward by a predetermined distance, and the light DLR, DLG, DLB is superimposed, whereby the low beam L, which is white light, can be formed as 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 the area where the light intensity is the largest, 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-described configuration, the following operational effects can be obtained.
As described above, with the vehicle headlamp 1 of the present embodiment, since at least one modulation portion MP is included in the incident point, the same light distribution pattern can be formed even when the incident point moves. When light is concentrated and incident on a specific region of the phase modulation element, the region generates heat and increases in temperature, and therefore, characteristics of the phase modulation element in the region change, and it is difficult to form a predetermined light distribution pattern. However, with the vehicle headlamp 1 of the present embodiment, since the incidence point is moved relative to the phase modulation element, concentrated incidence of light in a specific region of the phase modulation element can be suppressed, and a high temperature in the specific region can be suppressed. Therefore, the generation of a region where it is difficult to form a predetermined light distribution pattern is suppressed, and a desired light distribution pattern is easily obtained.
As described above, with the vehicle headlamp 1 of the present embodiment, the distance by which the incident point of the red laser light 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 distance by which the incident point of the blue laser beam moves along the incident surface of the phase modulation element 54B is equal to or greater than the diameter of the incident point. Therefore, as shown in fig. 3, the overlapping of the incidence point after the movement and the incidence point before the movement can be suppressed, and the specific region of the phase modulation element can be effectively suppressed from being heated.
As described above, with the vehicle headlamp 1 according to the present embodiment, since the incidence point of the red laser light, the incidence point of the green laser light, and the incidence point of the blue laser light are each periodically shifted, it is possible to effectively suppress incidence of light in a specific region of the phase modulation element for a long period of time, and it is possible to further suppress a temperature rise in the specific region of the phase modulation element. The period for moving the incident point can be appropriately changed in consideration of the heat resistance of the phase modulation element, for example. For example, the incident point may be shifted in two directions with a period of 1 second, and the period may be divided into 1-second periods.
As described above, in the vehicle headlamp 1 according to the present embodiment, the incident point can be moved in two directions by the point moving mechanism, and therefore, the incident point can be moved over 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 rise in the specific region can be effectively suppressed. The incident point may be moved in only one direction. In addition, the incidence point may be moved in three or more directions. When the incident point is moved in three or more directions, the incident surface of the phase modulation element can be moved over a wider range than when the incident point is moved in two directions. Therefore, the temperature rise in the specific region can be more effectively suppressed.
As described above, with the vehicle headlamp 1 of the present embodiment, the light sources 52R, 52G, 52B are held by the elastic connection portions of the circuit boards 59B, 59G, 59B, and therefore, only the light sources 52R, 52G, 52B can be moved.
As described above, with the vehicle headlamp 1 of the present embodiment, the phase modulation elements 54R, 54G, 54B are provided for each of the light sources 52R, 52G, 52B. That is, since the phase modulation elements 54R, 54G, 54B are provided in one-to-one correspondence with the light sources 52R, 52G, 52B, it is easy to adjust the light distribution pattern for each light source.
(Second embodiment)
Next, a second embodiment of the present invention will be described. In addition, the same or equivalent components as those of the first embodiment are denoted by the same reference numerals except for the specific description, and overlapping description thereof is omitted.
Fig. 7 is a view showing a lamp unit 20 of the vehicle headlamp 1 according to the 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, 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, 157B may be springs, for example.
With this configuration, the light sources 52R, 52G, 52B are mounted on the base 41 via the elastic members 157R, 157G, 157B, and therefore the light sources 52R, 52G, 52B passively vibrate in response to vibrations during running of the vehicle. Accordingly, the incident point moves relative to the phase modulation elements 54R, 54G, and 54B with the vibration of the light sources 52R, 52G, and 52B. Therefore, as in the first embodiment, light is suppressed from being concentrated in 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 described. In addition, the same or equivalent components as those of the first embodiment are denoted by the same reference numerals except for the specific description, and overlapping description thereof is omitted.
Fig. 8 is a view showing a lamp unit 20 of the vehicle headlamp 1 according to the third embodiment of the present invention, similarly to fig. 2. In fig. 8, a part of the housing 40 is omitted for easy understanding. As shown in fig. 8, the lamp unit 20 of the third embodiment is different from the lamp unit 20 of the first and second embodiments in which the optical system unit 50 is configured by three phase modulation elements 54R, 54G, 54B in that the number of phase modulation elements of the optical system unit 50 is one. The structure 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 is periodically moved in the front-rear direction and the depth direction. The first light source 52R is held by an 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 along 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 up-down direction and the depth direction. The second light source 52G is held by the elastic connection portion of the circuit board 59G, similarly to the first embodiment. Therefore, the light source 52G can move in the up-down direction and the depth direction along 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 is periodically moved in the up-down direction and the depth direction. The third light source 52B is held by the elastic connection portion of the circuit board 59B in the same manner as the first embodiment. Therefore, the light source 52B can move in the up-down direction and the depth direction along 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 outputs red laser light from the light sources 52G and 52B, and outputs green laser light from the light sources 52G and 52B, while outputs blue laser light from the light sources 52R and 52G, while outputs green laser light from the light sources 52R and 52B. That is, in the present embodiment, the red laser light from the light source 52R, the green laser light from the light source 52G, and the blue laser light from the light source 52B are emitted by switching at predetermined periods under the control of the control unit.
In addition, as in the first and second embodiments, the laser light emitted from the light sources 52R, 52G, 52B is collimated by the collimator lenses 53R, 53G, 53B.
A combining optical system 55 is provided above the collimator lens 53R and behind the collimator lenses 53G, 53B. That is, the first optical element 55f is provided above the collimator lens 53R and behind the collimator lens 53G, and the second optical element 55s is provided above the first optical element 55f and behind the collimator lens 53B. The optical elements 55f and 55s are arranged to be inclined at 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 laser light, the green laser light, and the blue laser light passing through the combining optical system 55 can be incident. 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 is opposite to the direction of the optical elements 55f and 55S.
The phase modulation element 54S is divided into a plurality of modulation portions as in the first and second embodiments, and by adjusting the reflectance of the liquid crystal layer at the point included in each light distribution pattern, each modulation portion can be used to form a light distribution pattern having the same shape as the light distribution pattern of the low beam. In the present embodiment, the entire region including at least one modulation section is included in each incidence point of the red laser light, the green laser light, and the blue laser light.
Next, emission of light from the lamp unit 20 according to the present embodiment will be described.
As described above, the red laser light from the light source 52R, the green laser light from the light source 52G, and the blue laser light from the light source 52B are emitted by switching at a predetermined period. For example, first, the red laser light is emitted from the first light source 52R for a predetermined time. In the case where a plurality of first light sources 52R for emitting red laser light are provided, the red laser light is emitted from the plurality of first light sources 52R for a predetermined time. During this time, the laser light from the light sources 52G, 52B is 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 is moved in two directions, the incidence point of the red laser light is also moved in two directions along the incidence plane of the phase modulation element 54S.
As described above, since at least one modulation unit is included in the incidence 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. In the case where a plurality of second light sources 52G for emitting green laser light are provided, the green laser light is 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 is moved in two directions, the incident point of the green laser light is also moved in two directions along the incident surface of the phase modulation element 54S.
As described above, since at least one modulation section is included in the incident point of the green laser light, 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 elapses, the red laser light from the light source 52G is in a non-emission state, and the blue laser light is emitted from the light source 52B for the predetermined time. In the case where a plurality of third light sources 52B for emitting blue laser light are provided, the blue laser light is 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 is moved in two directions, the incident point of the blue laser light is also moved in two directions along the incident surface of the phase modulation element 54S.
As described above, since at least one modulation section is included in the incidence point of the blue laser beam, third light DLB having a light distribution pattern having the same shape as the light distribution pattern of the low beam is emitted forward from phase modulation element 54S.
The above-described light emission cycle is repeated at a predetermined period. When the period of the emission cycle is shorter than the time resolution of human vision, an afterimage effect is generated, and the human can recognize that light of different colors is synthesized and irradiated. Therefore, by making the period shorter than the time resolution of the person, the person can recognize that white light in which red light DLR, green light DLG, and blue light DLB are synthesized is emitted from the lamp unit 20.
Further, 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. In addition, even if the period is greater than 1/30s, the afterimage effect is generated. For example, even if the period is 1/15s, the afterimage effect can be generated.
In the vehicle headlamp 1 according to the present embodiment, as in the first and second embodiments, since the incidence point moves on the incidence surface of the phase modulation element, it is possible to suppress light from being concentrated and incident on a specific region of the phase modulation element, and it is easy to obtain a desired light distribution pattern such as a low beam.
Further, with the vehicle headlamp 1 of the present embodiment, unlike the first and second embodiments in which the phase modulation elements are provided for each light source, the number of phase modulation elements constituting the optical system unit 50 can be reduced to use one, and therefore the number of components can be reduced, and cost reduction can be achieved.
In the present embodiment, the light sources 52R, 52G, and 52B are described as examples of the light emission, and at least two of the light sources 52R, 52G, and 52B may be configured to emit light at a predetermined cycle. For example, the third embodiment may be modified so 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 light and the green laser light from the light sources 52R and 52G, and a phase modulation element 54B that receives the blue laser light 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.
The present invention has been described above by taking the first, second and third embodiments as examples, and the present invention is not limited to these.
In the first, second, and third embodiments, an example has been described in which the light source is moved by fixing the phase modulation element to the base, and the incident point is moved on the incident surface of the phase modulation element. 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 point moving unit configured to move the light source as in the first, second, and third embodiments can more easily move the incident point on the incident surface of the phase modulation element.
In the first, second, and third embodiments, an example in which LCOS is used as the phase modulation element has been described, and a diffraction grating may be used as the phase modulation element. In the LCOS, as described above, the alignment pattern of the liquid crystal molecules is changed to generate a phase modulation element having a reflectance difference in the liquid crystal layer. In such LCOS, when the temperature of a specific region increases, the change in the alignment pattern of the region increases, and therefore it is likely that it is difficult to obtain a desired light distribution pattern. However, according to the first, second and third embodiments, since the incidence of light concentrated in a specific region of the LCOS is suppressed, and the increase in variation in the light distribution pattern is effectively suppressed, a desired light distribution pattern is easily obtained. Also, GLV (Grating Light Valve) may be used as the phase modulation element. The GLV is a reflective phase modulation element having a plurality of reflectors on a silicon substrate. With GLV, different diffraction patterns can be formed by electrically controlling the deflection of the plurality of reflectors. Thus, for example, the phase modulation element of the third embodiment may use GLV instead of LCOS.
In the first, second, and third embodiments, an example in which the phase modulation element is reflective has been described, but the phase modulation element may be transmissive.
In the first, second, and third embodiments, an example has been described in which the movement distance of the incident point is equal to or greater than the diameter of the incident point, but 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 the light at the incident point is generally different, and for example, a predetermined region such as a center region of the incident point tends to be a peak region of the power. When the size of the peak region is considered, if the distance of the 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 overlapping of the peak regions can be suppressed before and after the relative movement, and the increase in temperature of the specific region of the phase modulation element can be effectively suppressed. When the movement distance of the incident point is smaller than the diameter of the incident point, a region where the incident point before movement and the incident point after movement overlap can be generated, and the temperature rise may increase in this region. Therefore, the distance of movement of the incident point is more preferably equal to or longer than the diameter of the incident point.
In the first, second, and third embodiments, an example in which the incidence point is periodically moved has been described, but the incidence point may be periodically moved. When the incident point is not periodically moved, the period during which the incident point stays in the same area increases, and the temperature rise may increase in this area. Therefore, it is preferable that the incident point is periodically moved.
In the first, second, and third embodiments, the vehicle headlamp as the vehicle lamp having the three light sources 52R, 52G, 52B, each of which has one light source and the phase modulation element for receiving light from the light source, has been described. As in the first, second, and third embodiments, the vehicle lamp can generate light of a desired color such as white light by having a plurality of light sources that emit light of different wavelengths.
In the first, second, and third embodiments, the vehicle headlamp 1 as the vehicle lamp irradiates the low beam L, and the present invention is not particularly limited. For example, the vehicle lamp according to the other embodiment may be configured to radiate light having a lower intensity than the low beam L in a region indicated by a broken line in fig. 6, that is, a region above a region where the low beam L is radiated. Such low-intensity light is, for example, identification light OHS. In this case, the light emitted from each of the phase modulation elements 54R, 54G, and 54B preferably includes the identification light OHS. In such an embodiment, it can be understood that the low beam L and the sign recognition light OHS form a light distribution pattern for night illumination. Further, the term "night" herein does not simply mean "night", and includes a dark place such as a tunnel. The vehicle lamp according to another embodiment may be configured to radiate 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 the region HA2 is a region having a lower light intensity than the region HA 1. In addition, in another embodiment, the vehicle lamp of the present invention may be applied to a structure for forming an image. In this case, the direction of the light emitted from the vehicle lamp and the mounting position of the vehicle lamp 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 illustrated together with the drawings. The following exemplary embodiments are provided for ease of understanding 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 gist of the present invention.
(First embodiment)
Fig. 10 is a view schematically showing a cross section in the vertical direction of the vehicle lamp according to the present embodiment. The vehicle lamp of the present embodiment is a headlight 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 substantially symmetrical in the left and right directions. Therefore, in the present embodiment, one of the headlamps will be described. As shown in fig. 10, the headlamp 1 of the present embodiment has a housing 10 and a lamp unit 20 as main configurations.
The housing 10 has a lamp housing 11, a front cover 12, and a rear cover 13 as main structures. The front opening of the lamp housing 11 is closed, and the front cover 12 is fixed to 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.
The space formed by the lamp housing 11, the front cover 12 closing the front opening of the lamp housing 11, and the rear cover 13 closing the rear opening of the lamp housing 11 is a lamp room R, and the lamp unit 20 is housed in the lamp room R.
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.
The heat sink 30 has a metal bottom plate 31 extending in a substantially horizontal direction, and a plurality of heat radiating fins 32 are integrally provided with the bottom plate 31 on a lower surface side of the bottom plate 31. The cooling fan 35 is disposed with a gap from the heat radiating fins 32, and is fixed to the heat sink 30. The radiator 30 is cooled by the air flow generated by the rotation of the cooling fan 35. 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 has a substantially rectangular shape and is made of a metal such as aluminum. An optical system unit 50 is housed in the 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 make the inner wall of the cover 40 light-absorbing, it is preferable to perform a black alumina film process or the like on the inner wall. By making the inner walls of the cover 40 light-absorbing, even when light is irradiated to these inner walls by unexpected reflection, or the like, reflection of the irradiated light can be suppressed and emitted from the opening 40H in unexpected directions.
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 guiding optical system 155, and a phase modulation element assembly 54.
The first light-emitting optical system 51R includes a first light source 52R and a first collimating lens 53R. The first light source 52R is a laser device that emits laser light in a predetermined wavelength band, and in the present embodiment, is a semiconductor laser that emits laser light having a peak wavelength of power of, for example, 638nm, which is red. The optical system unit 50 has 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 fast axis direction and the slow axis direction of the laser beam emitted from the first light source 52R. 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 collimator lens 53R, a collimator lens for collimating the fast axis direction of the laser light and a collimator lens for collimating the slow axis direction may be provided.
The second light-emitting optical system 51G has a second light source 52G and a second collimator lens 53G, and the third light-emitting optical system 51B has a third light source 52B and a third collimator lens 53B. The light sources 52G and 52B are laser elements that emit laser light in a predetermined wavelength band, respectively. In the present embodiment, the second light source 52G is a semiconductor laser that emits green laser light having a peak wavelength of, for example, 515nm, and the third light source 52B is a semiconductor laser that emits blue laser light having a peak wavelength of, for example, 445 nm. Therefore, in the present embodiment, the three light sources 52R, 52G, 52B emit laser light in predetermined wavelength bands different from each other. The light sources 52G and 52B are mounted on the circuit board, respectively, similarly to the first light source 52R.
The second collimator lens 53G collimates 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 collimates 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 these collimator lenses 53G and 53B, a collimator lens for collimating the fast axis direction of the laser light and a collimator lens for collimating 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 reflecting mirror 155m, a first optical element 155f, and a second optical element 155s. The 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 mirror 155m, and reflects the light LG emitted from the second light-emitting 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 such a first optical element 155f and a second optical element 155s, a wavelength selective filter in which an oxide film is laminated on a glass substrate can be exemplified. 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 combine the light rays LR, LG, and LB, but emits the light rays LR, LG, and LB in parallel in the lateral direction, and the light rays LR, LG, and LB are made to enter the phase modulation element assembly 54. In the present embodiment, these lights LR, LG, and LB are aligned in a direction perpendicular to the paper surface of fig. 11. In fig. 11, light LR is indicated by a solid line, light LG is indicated by a broken line, light LB is indicated by a one-dot chain line, and these lights LR, LG, and LB are indicated by a shift.
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 is incident is inclined at approximately 45 degrees with respect to the vertical direction, and the light LR, LG, LB emitted from the light guide optical system 155 is incident on the incident surface EF. The incident surface EF may be non-parallel to the horizontal direction, and for example, the phase modulation element assembly 54 may be arranged 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 emitting 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 emitting optical system 51G. In addition, 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 assembly 54 includes: the phase modulation element diffracts the light LR from the first light emitting optical system 51R to form the light LR into a predetermined light distribution pattern, the phase modulation element diffracts the light LG from the second light emitting optical system 51G to form the light LG into a predetermined light distribution pattern, and the phase modulation element 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 aligned in one direction, and the incidence surface EF of the phase modulation element assembly 54 is formed by the incidence surface of the light of these phase modulation elements.
In the present embodiment, the three phase modulation elements are reflective phase modulation elements that diffract incident light while reflecting the light, and are each emitted, specifically, reflective LCOS (Liquid Crystal On Silicon: liquid crystal silicon on device). Therefore, the phase modulation element assembly 54 diffracts the first light DLR that diffracts the red light LR, the second light DLG that diffracts the green light LG, and the third light DLB that diffracts the blue light LB by the phase modulation elements corresponding to the light LR, LG, and LB incident on the incident surface EF, and emits the light beams from the incident surface EF. The light DLR, DLG, DLB emitted from the phase modulation element assembly 54 in this way is emitted from the optical system unit 50. In fig. 10 and 11, first light DLR is indicated by a solid line, second light DLG is indicated by a broken line, third light DLB is indicated by a one-dot chain line, and these lights DLR, DLG, DLB are indicated by a shift.
Next, the structure of the phase modulation element assembly 54 according to 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 a main view, and the entire area in the main 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 elongated in the horizontal direction. In the following description, in a front view of the phase modulation element assembly 54, a direction parallel to the horizontal direction is a lateral direction, and a direction perpendicular to the lateral direction is a longitudinal direction. Therefore, the lateral direction is a direction parallel to the horizontal direction, the longitudinal direction is a direction parallel to the direction in which the vertical direction is projected onto 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 emitting optical system 51R, a second phase modulation element 54G corresponding to the second light emitting optical system 51G, and a third phase modulation element 54B corresponding to the third light emitting 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 longitudinal direction of the phase modulation element assembly 54. Through the drive circuit 60R, electric power is supplied to the phase modulation elements 54R, 54G, and 54B constituting the phase modulation element assembly 54, respectively.
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 modulating element 54R in the lateral direction, the width WG of the second phase modulating element 54G in the lateral direction, and the width WB of the third phase modulating element 54B in the lateral direction are smaller than the width H54 of the phase modulating 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, that is, the longitudinal direction. As described above, the entire area of the phase modulation element assembly 54 in the main 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 beams of the phase modulation elements 54R, 54G, and 54B, so that the incident surfaces of the light beams 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 longitudinal 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 transverse 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 transverse 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 transverse direction of the incident surface of the third phase modulation element 54B. In the present embodiment, 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 the widths WG, WB. Therefore, the widths WG, WB of the incident surfaces of the phase modulation elements 54G, 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, WB.
The first phase modulation element 54R has a plurality of modulation units MPR arranged in a matrix. The second phase modulation element 54G has a plurality of modulation units MPG arranged in a matrix, and the third phase modulation element 54B has a plurality of modulation units MPB arranged in a matrix. In this embodiment, these modulation units MPR, MPG, MPB have square shapes of the same size. Therefore, the number of modulation units MPR aligned in the longitudinal direction is larger than the number of modulation units MPR aligned in the transverse direction. The number of modulation units MPG aligned in the longitudinal direction is larger than the number of modulation units MPG aligned in the transverse direction, and the number of modulation units MPB aligned in the longitudinal direction is larger than the number of modulation units MPB aligned in the transverse direction. Each modulation unit MPR, MPG, MPB includes a plurality of dots arranged in a matrix, and light incident on the modulation unit MPR, MPG, 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 diffracted by the light LG. 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 third light DLB diffracted by the blue light LB.
Fig. 12 shows an incidence point SR, which is a region where red light LR is irradiated, an incidence point SG, which is a region where green light LG is irradiated, and an incidence point SB, which is a region where blue light LB is irradiated. In the present embodiment, as described above, the light sources 52R, 52G, 52B are semiconductor lasers, and therefore, the lasers emitted from the light sources 52R, 52G, 52B propagate while expanding in a substantially elliptical shape. The laser beams emitted from the light sources 52R, 52G, and 52B are collimated by the collimator lenses 53R, 53G, and 53B in the fast axis direction and the slow axis direction, 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 assembly 54 via the light guiding optical system 155. In the present embodiment, in the light guide optical system 155, the shapes of the light rays LR, LG, and LB are not adjusted, and therefore the shapes of the incident points SR, SG, and SB are substantially elliptical.
In the present embodiment, the size of the incidence point SR having a substantially elliptical shape is such that the incidence point SR can include at least one modulation unit MPR, and the long axis LAR of the incidence point SR is substantially parallel to the lateral direction. In other words, the incident point SR has a substantially elliptical shape elongated in the lateral direction, and the longitudinal direction of the incident point SR is not parallel to the longitudinal direction. The size of the incidence point SG having a substantially elliptical shape is such that at least one modulation unit MPG can be included, and the major axis LAG of the incidence point SG is substantially parallel to the longitudinal direction. In other words, 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. The size of the incidence point SB having a substantially elliptical shape is such that the incidence point SB can include at least one modulation unit MPB, and the major axis LAB of the incidence point SB is substantially parallel to the longitudinal direction. In other words, the incident point SB has 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 of the incident point SR of the first phase modulation element 54R in the longitudinal direction is smaller than the width SHG of the incident point SG of the second phase modulation element 54G in the longitudinal direction. The vertical width SHG of the incident point SG is substantially the same as the vertical width SHB of the incident point SB of the third phase modulation element 54B. In addition, the width SHG and the width SHB may also be different from each other.
Fig. 13 is a diagram 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 silicon substrate 62, a drive circuit layer 63, a plurality of electrodes 64, a reflective film 65, a liquid crystal layer 66, a transparent electrode 67, and a light-transmitting substrate 68 as main structures.
The plurality of electrodes 64 are arranged in a matrix on one surface side of the silicon substrate 62 so as to correspond to the respective points in one-to-one correspondence. 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 light-transmitting substrate 68 is disposed opposite to the silicon substrate 62 on one side of the silicon substrate 62, and is, for example, a glass substrate. The transparent electrode 67 is disposed on the surface of the transparent 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 is incident from the incident surface EF on the opposite side of the light transmissive substrate 68 from the silicon substrate 62 side.
As shown in fig. 13, light RL incident from an incident surface EF on the opposite side of the silicon substrate 62 side of the light-transmitting 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 light-transmitting substrate 68. When a voltage is applied between the 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. According to the change in alignment of the liquid crystal molecules 66a, the reflectance of the liquid crystal layer 66 located between the electrode 64 and the transparent electrode 67 changes, and the optical path length of the light RL transmitted through the liquid crystal layer 66 changes. Therefore, by transmitting the light RL through the liquid crystal layer 66 and emitting the light RL 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 each modulator MPR, MPG, MPB, the alignment of the liquid crystal molecules 66a can be changed by controlling the voltage applied between the electrode 64 and the transparent electrode 67 corresponding to each point DT, and the amount of change in the phase of the light emitted from each point DT can be adjusted according to each point DT. Since the light having different phases interfere with each other and diffract, the light emitted from the point DT interferes and diffracts, and the diffracted light is emitted from the phase modulation element assembly 54. Therefore, the phase modulation element assembly 54 can diffract the incident light and emit the 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 area where 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 on each modulation section MPR of the first phase modulation element 54R of the phase modulation element assembly 54. The same phase modulation pattern is formed on each modulation section MPG of the second phase modulation element 54G, and the same phase modulation pattern is formed on each modulation section MPB of the third phase modulation element 54B. In this specification, the phase modulation pattern means a pattern that modulates 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 the 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 set to a desired light distribution pattern. In the present embodiment, the respective phase modulation patterns of the modulation unit MPR, MPG, MPB are different from each other.
Specifically, in the present embodiment, the respective phase modulation patterns of the modulator MPR, MPG, MPB are phase modulation patterns that diffract the light LR, LG, and LB, respectively, so that the light combined by 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 the low beam. In other words, the phase modulation elements 54R, 54G, 54B of the phase modulation element assembly 54 diffract the incident light LR, LG, LB, respectively, so that the light that is synthesized by the light DLR, DLG, DLB emitted from the phase modulation elements 54R, 54G, 54B, respectively, 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 with and is based on the intensity distribution of the light distribution pattern of the low beam. Third light DLB emitted from third phase modulation element 54B is an intensity distribution that coincides 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. As described above, the phase modulation elements 54R, 54G, and 54B have the plurality of modulation portions MPR, MPG, MPB forming the same phase modulation pattern, and diffract the light LR, LG, and LB, respectively, so that the respective modulation portions MPR, MPG, MPB become the light distribution patterns. The phase modulation elements 54R, 54G, and 54B preferably diffract the incident light LR, LG, and LB so that the outer shape of the light distribution pattern of the light DLR, DLG, DLB emitted from the phase modulation elements 54R, 54G, and 54B matches the outer shape of the light distribution pattern of the low beam. Thus, the first phase modulation element 54R emits light DLR of the red component of the light distribution pattern of the low beam, the second phase modulation element 54G emits light DLG of the green component of the light distribution pattern of the low beam, and the third phase modulation element 54B emits light DLB of the blue component of the light distribution pattern of the low beam.
Next, emission of light from the headlight 1 will be described. Specifically, a case where a low beam is emitted from the headlight 1 will be described.
By supplying power to the light sources 52R, 52G, and 52B from a power source not shown, 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 lasers 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, LB emitted from the light-emitting optical systems 51R, 51G, 51B enters the light-guiding optical system 155.
In the light guide optical system 155, the light LR from the first light emitting optical system 51R is reflected by the reflecting 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. In this way, 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 guiding 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 exits from the light-guiding optical system 155. In this way, 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 guiding optical system 155. The light LB from the third light emitting optical system 51B is reflected by the second optical element 155s and emitted from the light guide optical system 155. The light LB emitted from the light guide optical system 155 in this way 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 modulation element 54B of the phase modulation element assembly 54 by the light guiding 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, and emits the first light DLR, which is the light of the red component of the light distribution pattern of the 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 light of the green component of the light distribution pattern of the near light. The third phase modulation element 54B diffracts the light LB incident on the third phase modulation element 54B, and emits third light DLB, which is light of the blue component of the low beam light distribution pattern. In this way, the lights DLR, DLG, DLB emitted from the phase modulation element assembly 54 are respectively irradiated to the outside of the headlamp 1 through the front cover 12. At this time, the light DLR, DLG, DLB is irradiated at a focal position at a predetermined distance from the vehicle so that the areas where the respective lights are irradiated 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, DLB is a light distribution pattern of low beam, the irradiated light is low beam. The light DLR, DLG, DLB is preferably configured to have substantially uniform outer shapes of the respective light distribution patterns at the focal positions.
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 of low beam, and fig. 14 (B) is a view showing a light distribution pattern of high beam. In fig. 14, S represents a horizontal line, and a light distribution pattern is represented by a thick line. The area PLA1 in the light distribution pattern PL of the low beam, which is the light distribution pattern for night illumination shown in fig. 14 (a), is the area with the highest intensity, and the intensity is reduced in the order of the areas PLA2 and PLA 3. That is, the phase modulation elements 54R, 54G, and 54B of the phase modulation element assembly 54 diffract the light so that the combined light forms a light distribution pattern including the intensity distribution of the low beam. In fig. 14, as shown by a broken line, light having a lower intensity than the low beam may be irradiated from the head lamp 1 above a position where the low beam is irradiated. The light is the light OHS for identification. In this case, the light DLR, DLG, DLB emitted from the respective phase modulation elements 54R, 54G, 54B of the phase modulation element assembly 54 preferably includes the identification light OHS. In this case, it can be understood that a light distribution pattern for night illumination is formed by using the low beam and the sign recognition light OHS. The light distribution pattern for night illumination is used not only at night but also in a dark place such as a tunnel.
As described above, the headlamp 1 of the present embodiment includes: light sources 52R, 52G, 52B that emit light; a phase modulation element assembly 54 having 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 has a plurality of modulation portions MPR that diffract the light LR from the first light source 52R to form the light LR into a predetermined light distribution pattern. The second phase modulation element 54G has a plurality of modulation portions MPG that diffract the light LG from the second light source 52G to form the light LG into a predetermined light distribution pattern. The third phase modulation element 54B has a plurality of modulation portions MPB that diffract the light LB from the third light source 52B to form the light LB into a predetermined light distribution pattern. 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 transverse direction of the incident surface. The vertical width H54 of the incident surface of the second phase modulation element 54G is larger than the horizontal width WG of the incident surface, and the vertical width H54 of the incident surface of the third phase modulation element 54B is larger than the horizontal width WB of the incident surface. The light LR of the first phase modulation element 54R has a size capable of containing at least one modulation unit MPR, the light LG of the second phase modulation element 54G has a size capable of containing at least one modulation unit MPG, and the light LB of the third phase modulation element 54B has a size capable of containing at least one modulation unit MPB. At least a part of the plurality of modulation units MPR are aligned in the vertical direction, at least a part of the plurality of modulation units MPG are aligned in the vertical direction, and at least a part of the plurality of modulation units MPB are aligned in the vertical direction.
The amplitude of the vibration of the vehicle in the vertical direction tends to be larger than the amplitude of the vibration in the horizontal direction, and the headlamp 1 vibrates similarly to the vehicle. Accordingly, the incident points SR, SG, SB of the light LR, LG, LB of the phase modulation elements 54R, 54G, 54B of the phase modulation element assembly 54 tend to vibrate in the vertical direction as compared with the horizontal direction. That is, the incident points SR, SG, SB tend to vibrate in the vertical direction, that is, in the longitudinal direction, which is the direction parallel to the direction projected onto the incident surface EF, as compared with the lateral direction, that is, the 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, 54B is larger than the widths WR, WG, WB in the transverse 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 the exposure of a part of the incidence points SR, SG, SB from the incidence surfaces of the phase modulation elements 54R, 54G, 54B, and can suppress the reduction of energy efficiency. In the headlamp 1 of the present embodiment, as described above, the respective incident points SR, SG, SB have a size that can include at least one modulation unit MPR, MPG, MPB. At least a part of each of the modulation units MPR, MPG, MPB is juxtaposed in the longitudinal direction. Therefore, in the headlamp 1 of the present embodiment, even when the incidence points SR, SG, SB are shifted in the longitudinal direction due to the vibration of the vehicle, the light LR can be incident on any of the modulation portions MPR, the light LG can be incident on any of the modulation portions MPG, and the light LB can be incident on any of the modulation portions MPG. Therefore, the headlamp 1 of the present embodiment can form the light distribution pattern PL of the low beam even in this case.
The headlamp 1 of the present embodiment includes a plurality of light sources 52R, 52G, 52B, and the phase modulation element assembly 54 includes: the first phase modulation element 54R into which the light LR from the first light source 52R is incident, the second phase modulation element 54G into which the light LG from the second light source 52G is incident, and the third phase modulation element 54B into which the light LB from the third light source 52B is incident. That is, these phase modulation elements 54R, 54G, 54B of the phase modulation element aggregate 54 are provided for each light source 52R, 52G, 52B. In addition, 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 vertical width SHR of the incident point SR of the first phase modulation element 54R is smaller than the vertical widths SHG and SHB of the incident point SG of the second phase modulation element 54G and the third phase modulation element 54B. That is, the width SHR in the longitudinal 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 smaller than the largest width among the widths SHG, SHB in the longitudinal direction of the incident points SG, SB of the other phase modulation elements 54G, 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 of the incident point SR of the first phase modulation element 54R in the longitudinal direction of the incident point SR is smaller than the width of the incident points SG, SB of the other phase modulation elements 54G, 54B. Therefore, even if the width in the longitudinal direction of the incidence plane of the phase modulation element 54R, 54G, 54B and the optical path length between the phase modulation element 54R, 54G, 54B and the light source 52R, 52G, 52B are not adjusted, it is possible to suppress that a part of the incidence point SR of the first phase modulation element 54R, which is liable to increase in amplitude of the vibration of the incidence point with respect to the phase modulation element, is exposed from the incidence plane of the phase modulation element 54R. Accordingly, the degree of freedom in the arrangement of the phase modulation elements 54R, 54G, 54B with respect to the size of the phase modulation elements 54R, 54G, 54B and the light sources 52R, 52G, 52B can be improved.
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 of 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 vertical direction, which is the longitudinal direction. Therefore, the width SHR of the incident point SR in the vertical direction can be reduced as compared with a case where the specific direction, which is the long side direction of the incident point SR, is parallel to the vertical direction. Therefore, when the incident point SR is vibrated in the vertical direction according 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 addition, from the viewpoint of suppressing a part of the incident point SR from being exposed from the incident surface of the first phase modulation element 54R due to the vibration of the vehicle, 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, as in the present embodiment.
In the headlamp 1 of the present embodiment, the incidence point SG of the second phase modulation element 54G has a substantially elliptical shape elongated in the specific direction, and the specific direction, which is the longitudinal direction of the incidence point SG, is not parallel to the horizontal direction, which is the lateral direction. The incident point SB of the third phase modulation element 54B is substantially elliptical and elongated in a specific direction, and the specific direction, which is the longitudinal direction of the incident point SB, is not parallel to the horizontal direction, which is the lateral direction. Therefore, compared with the case where the specific direction, which is the longitudinal direction of the incident points SG, SB, is parallel to the horizontal direction, the width of the phase modulation elements 54G, 54B in the horizontal direction, which is the lateral direction, can be reduced, and the manufacturing cost of the headlamp 1 can be reduced. In addition, from the viewpoint of reducing the lateral widths WG, WB of the phase modulation elements 54R, 54B, it is preferable that the specific direction, which is the longitudinal direction of the incident points SG, SB, be parallel to the vertical direction, which is the longitudinal direction, as in the present embodiment.
In the headlamp 1 according to the present embodiment, the number of modulation portions MPR arranged in the longitudinal direction is larger than the number of modulation portions MPR arranged in the lateral direction. The number of modulation units MPG aligned in the longitudinal direction is larger than the number of modulation units MPG aligned in the transverse direction, and the number of modulation units MPB aligned in the longitudinal direction is larger than the number of modulation units MPB aligned in the transverse direction.
Therefore, when the incident point SR vibrates in the longitudinal direction due to the vibration of the vehicle, the light LR from the first light source 52R is likely to be incident on any one of the modulation sections MPR, as compared with the case where the number of modulation sections MPR juxtaposed in the longitudinal direction is smaller than the number of modulation sections MPR juxtaposed in the lateral direction. In addition, like the modulation units 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 modulation units MPG. In addition, when the incident point SB vibrates in the longitudinal direction due to vibration of the vehicle, the light LB from the third light source 52B is likely to be incident on any one of the modulation portions MPB, as in the modulation portion MPR.
(Second embodiment)
Next, a second embodiment of the present invention will be described in detail with reference to fig. 15. In addition, the same or equivalent components as those of the first embodiment are denoted by the same reference numerals unless otherwise specified, and overlapping description thereof is omitted.
Fig. 15 is a view showing an optical system unit according to a second embodiment of the present invention, similar to fig. 11. In fig. 15, description of the heat sink 30, the cover 40, and the like is omitted for ease of 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 guiding optical system 155.
The phase modulation elements 54R, 54G, and 54B of the present embodiment are LCOS, as in 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 view of the incident surface EFR on which light is incident. Therefore, the longitudinal width of the incident surface EFR of the first phase modulation element 54R is larger than the transverse width of the incident surface EFR of the first phase modulation element 54R. The first phase modulation element 54R has a plurality of modulation units MPR arranged in a matrix, and the number of modulation units MPR of the first phase modulation element 54R aligned in the longitudinal direction is greater than the number of modulation units MPR aligned in the lateral direction. For example, the first phase modulation element 54R is provided with light LR from the first light source 52R, and the first phase modulation element 54R emits first light DLR that diffracts the light LR. In the present embodiment, as in the first embodiment, the shape of the light LR from the first light source 52R as the semiconductor laser is not adjusted, and therefore the shape of the incident point SR of the first phase modulation element 54R is a substantially elliptical shape. In the present embodiment, as in the first embodiment, the size of the incidence point SR having a substantially elliptical shape is such that at least one modulation section MPR can be included, and the long axis LAR of the incidence point SR is substantially parallel to the horizontal direction, that is, 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 view of the incident surface EFG side 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 transverse 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 of the second phase modulation element 54G aligned in the longitudinal direction is larger than the number of modulation units MPG aligned in the lateral direction. The second phase modulation element 54G receives the light LG from the second light source 52G, and the second phase modulation element 54G emits second light DLG that 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 is not adjusted, the shape of the incidence 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 incidence 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 incidence point SG is substantially parallel to the vertical direction, that is, the longitudinal direction.
The third phase modulation element 54B of the present embodiment is formed in a substantially rectangular shape elongated in the longitudinal direction when viewed from the front view on the incident surface EFB side on which light is incident. Therefore, the longitudinal width of the incident surface EFB of the third phase modulation element 54B is larger than the transverse width of the incident surface EFB of the third phase modulation element 54B. The third phase modulation element 54B has a plurality of modulation units MPB arranged in a matrix, and the number of modulation units MPB arranged in the longitudinal direction of the third phase modulation element 54B is greater than the number of modulation units MPB arranged in the lateral direction. The third phase modulation element 54B receives the light LB from the third light source 52B, 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 is not adjusted, the shape of the incident point SB of the third phase modulation element 54B is substantially elliptical. In the present embodiment, as in the first embodiment, the size of the substantially elliptical incidence point SB is such that at least one modulation portion MPB can be included, and the long axis LAB of the incidence point SB is substantially parallel to the vertical direction, that is, the longitudinal direction.
The combining optical system 55 of the present embodiment includes a first optical element 55f and a second optical element 55s. 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, first optical element 55f synthesizes first light DLR and second light DLG by transmitting first light DLR and reflecting second light DLG. The second optical element 55s is an optical element for combining the first light DLR and the second light DLG combined by the first optical element 55f with the third light DLB emitted from the third phase modulation 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 first optical element 55f and second optical element 55s, a wavelength selective filter in which an oxide film is laminated on a glass substrate can be exemplified. 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, in the combining optical system 55, the first light DLR, the second light DLG, and the third light DLB are combined, and the light is emitted from the combining optical system 55. In fig. 15, first light DLR is indicated by a solid line, second light DLG is indicated by a broken line, third light DLB is indicated by a one-dot chain line, and these lights DLR, DLG, DLB are indicated by a shift.
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 so that the light DLR, DLG, DLB emitted from the phase modulation elements 54R, 54G, and 54B, respectively, is a light distribution pattern PL of low beam after being combined by the combining optical system 55. Therefore, the first light DLR, which is the red component light of the low-beam light distribution pattern PL, is emitted from the first phase modulation element 54R, the second light DLG, which is the green component light of the low-beam light distribution pattern PL, is emitted from the second phase modulation element 54G, and the third light DLB, which is the blue component light of the low-beam light distribution pattern PL, is emitted from the third phase modulation element 54B.
In this way, the light DLR, DLG, DLB is 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, even when the incident points SR, SG, SB vibrate in the longitudinal direction due to the vibration of the vehicle, as in the first embodiment, it is possible to suppress the exposure of a part of the incident points SR, SG, SB from the incident surface EFR, EFG, EFB of the phase modulating element 54R, 54G, 54B, and to suppress the reduction of energy efficiency. In the headlamp 1 of the present embodiment, even when the incident points SR, SG, SB vibrate in the longitudinal direction due to the vibration of the vehicle, the light LR can be incident on any of the modulation portions MPR, the light LG can be incident on any of the modulation portions MPG, and the light LB can be incident on any of the modulation portions MPB, as in the first embodiment. Therefore, even in such a case, the headlamp 1 of the present embodiment can form the light distribution pattern PL of the low beam.
(Third embodiment)
Next, a third embodiment of the present invention will be described in detail. The same or equivalent components as those of the first embodiment are denoted by the same reference numerals unless otherwise specified, and overlapping description thereof is omitted. The optical system unit 50 of the present embodiment is mainly different from the optical system unit 50 of the first embodiment 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 viewed from the incident surface side on which light is incident, and the phase modulation element 54S is schematically shown in fig. 16.
In the present embodiment, the phase modulation element 54S has the same structure 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, that is, in the longitudinal direction, when viewed from the 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 transverse direction of the incident surface of the phase modulation element 54S. The phase modulation element 54S has a plurality of modulation sections MPS arranged in a matrix, as in the phase modulation element 54R of the first embodiment. The number of modulation sections MPS aligned in the longitudinal direction is larger than the number of modulation sections MPS aligned in the transverse direction. The modulation unit MPS includes a plurality of dots arranged in a matrix, and diffracts and emits light incident on the modulation unit MPS, similarly to the modulation unit MPR of the first embodiment.
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 guiding optical system 155 and is incident on the phase modulation element 54S, as in the first embodiment described above. Therefore, the incidence of these lights LR, LG, and LB on the phase modulation element 54S will be described below with reference to fig. 11. In the present embodiment, the power supplied to the light sources 52R, 52G, 52B is adjusted, laser light is alternately emitted to each of the light sources 52R, 52G, 52B, and light LR, LG, LB is alternately emitted to each of the light emitting optical systems 51R, 51G, 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 and 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 and 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 and LG. The emission of the laser light from each of the light sources 52R, 52G, 52B is sequentially switched, and the emission of the light LR, LG, LB from each of the light-emitting optical systems 51R, 51G, 51B is sequentially switched. Accordingly, the light LR, LG, and LB emitted from these light-emitting optical systems 51R, 51G, and 51B, which are different in wavelength band from each other, sequentially enter the phase modulation element 54S. The phase modulation element 54S sequentially emits light DLR, DLG, DLB obtained by diffracting the incident light LR, LG, and LB. In the present embodiment, as in the first embodiment described above, 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 incidence point SR, which is a region where red light LR is irradiated, an incidence point SG, which is a region where green light LG is irradiated, and an incidence point SB, which is a region where blue light LB is irradiated. In fig. 16, an incident point SR is indicated by a solid line, an incident point SG is indicated by a broken line, and an 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 light LR, LG, and LB from the light sources 52R, 52G, and 52B as the semiconductor laser light are not adjusted, the shapes of the incident points SR, SG, and SB of the light LR, LG, and LB of the phase modulation element 54S are substantially elliptical. In the present embodiment, the magnitudes of the substantially elliptical incidence points SR, SG, SB are each a magnitude that can include at least one modulation section MPS. In addition, these incidence points SR, SG, SB overlap each other.
In the present embodiment, the incident point SR has a substantially elliptical shape elongated in the lateral 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. 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 longitudinal width of the incident point SR is smaller than the longitudinal width of the incident point SG, and the longitudinal width of the incident point SG is substantially the same as the longitudinal width of the incident point SB.
Next, light emitted from the phase modulation element 54S of the present embodiment will be described. Specifically, a case where the headlight 1 emits light of the low beam light distribution pattern PL 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 light LR from light source 52R is incident, phase modulation element 54S forms a phase modulation pattern corresponding to light source 52R, that is, a phase modulation pattern in which first light DLR emitted from phase modulation element 54S forms the red component light of the low-beam light distribution pattern. Therefore, when the light LR from the light source 52R is incident, 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 second light DLG emitted from the phase modulation element 54S forms a phase modulation pattern of light of a green component of the light distribution pattern of the low beam. Therefore, when the light LG from the light source 52G is incident, the phase modulation element 54S emits the second light DLG, which is light of the green component of the light distribution pattern of the low beam. When light LB from light source 52B is incident, phase modulation element 54S forms a phase modulation pattern corresponding to light source 52B, that is, a phase modulation pattern in which third light DLB emitted from phase modulation element 54S forms light of a blue component of the light distribution pattern of the low beam. Therefore, when the light LB from the light source 52B is incident, the phase modulation element 54S emits the third light DLB, which is light of the blue component of the low beam light distribution pattern.
That is, the phase modulation element 54S 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, by changing the phase modulation pattern according to the wavelength band of the light LR, LG, LB thus incident. These lights DLR, DLG, DLB are emitted from the openings 40H of the cover 40, respectively, and sequentially irradiate the outside of the headlamp 1 through the front cover 12. At this time, first light DLR, second light DLG, and third light DLB are irradiated at focal positions at a predetermined distance from the vehicle so that the respective light irradiation regions overlap with each other. The focal position is, for example, a position 25m from the vehicle. Further, the first light DLR, the second light DLG, and the third light DLB are preferably irradiated so that the outer shape of the area irradiated with each light DLR, DLG, DLB at the focal position is substantially uniform. In the present embodiment, the lengths of the emission times of the laser beams emitted from the light sources 52R, 52G, and 52B are substantially the same, and therefore the lengths of the emission times of the light DLR, DLG, DLB are also substantially the same.
In addition, when light of different colors is repeatedly irradiated at a period shorter than the time resolution of human vision, the human can recognize that light obtained by combining the light of different colors is irradiated due to an afterimage phenomenon. In the present embodiment, when the time for which the laser beam is emitted from the first light source 52R and then the laser beam is emitted from the first light source 52R is again shorter than the time resolution of human vision, the light DLR, DLG, DLB emitted from the phase modulation element 54S is repeatedly irradiated with the light DLR of red, the light DLG of green, and the light DLB of blue in a cycle shorter than the time resolution of human vision, and the light DLR of red, the light DLG of green, and the light DLB of blue are combined by the afterimage phenomenon. As described above, the respective emission times of the light DLR, DLG, DLB are substantially the same, and the intensities of the laser beams emitted from the light sources 52R, 52G, 52B are the same predetermined intensities as those of the first embodiment. Therefore, the color of the light synthesized due to the afterimage phenomenon is the same white as the light synthesized by the light DLR, DLG, DLB of the first embodiment. Further, since the light distribution pattern of the light DLR, DLG, DLB synthesized by the light is the light distribution pattern PL of the low beam, the light distribution pattern of the light DLR, DLG, DLB synthesized by the afterimage phenomenon is also the light distribution pattern PL of the low beam. Thus, the light of the low beam light distribution pattern PL is emitted from the headlight 1.
From the viewpoint of suppressing the flicker perceived by the light synthesized by the afterimage phenomenon, the period of repeatedly emitting the laser light from the light sources 52R, 52G, 52B is preferably 1/15s or less. The time resolution of human vision is approximately 1/30s. In the vehicle lamp, the flicker of light can be suppressed as long as the emission period of light is about 2 times. When the period is 1/30s or less, the time resolution of human vision is substantially exceeded. Therefore, the perceived flickering of light can be further suppressed. In addition, from the viewpoint of further suppressing the perceived flicker of 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 transverse direction of the incident surface. The incident points SR, SG, SB of the phase modulation element 54S are each sized to include at least one modulation unit MPS, and at least a part of the plurality of modulation units MPS are juxtaposed in the longitudinal direction. Therefore, the headlamp 1 of the present embodiment can form the light distribution pattern PL of the low beam even when the incident points SR, SG, SB are moved in the longitudinal direction due to the vibration of the vehicle, as in the first embodiment.
In the present embodiment, as described above, the width in the longitudinal direction of the incident point SR having the largest optical path length with respect to the corresponding light source is equal to or smaller than the largest width in the longitudinal direction of the other incident points SG, SB. Therefore, in the headlamp 1 of the present embodiment, as in the first embodiment, even if 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, 52B are not adjusted, it is possible to suppress that a part of the incident point SR, at which the amplitude of the vibration of the phase modulation element 54S tends to increase, is exposed from the incident surface of the phase modulation element 54S.
In the present embodiment, the incident point SR 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 vertical direction, which is the longitudinal 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 modulation units MPS aligned in the longitudinal direction is larger than the number of modulation units MPS aligned in the transverse direction. Therefore, as in the first embodiment, when the incidence points SR, SG, SB vibrate in the longitudinal direction due to vibration of the vehicle, the light LR, LG, LB from the light sources 52R, 52G, 52B is likely to be incident on any one of the modulation portions MPG, as compared with the case where the number of the modulation portions MPS juxtaposed in the longitudinal direction is smaller than the number of the modulation portions MPS juxtaposed in the lateral direction.
In the headlamp 1 of the present embodiment, since the phase modulation elements for diffracting 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 way of example of the above embodiments, and the present invention is not limited to this.
The vehicle lamp of the present invention includes: the light source and the phase modulation element having a plurality of modulation units for diffracting light from the light source to form a predetermined light distribution pattern are not particularly limited, as long as the light source has a plurality of modulation units, and the width in the longitudinal direction of the incident surface of the phase modulation element on which the light is incident is larger than the width in the transverse direction of the incident surface, and the size of the incident point of the light of the phase modulation element is a size capable of including at least one modulation unit. Even when the incident point vibrates in the longitudinal direction due to vibration of the vehicle, the vehicle lamp having such a configuration can suppress exposure of a part of the incident point from the incident surface of the phase modulation element, and can suppress a decrease in energy efficiency. In addition, even when the incident point vibrates in the longitudinal direction due to vibration of the vehicle, the vehicle lamp can cause light to be incident on any one of the modulation portions, and thus a predetermined light distribution pattern can be formed.
In the above embodiment, the headlight 1 as the vehicle lamp irradiates a low beam, and the present invention is not particularly limited. For example, the vehicle lamp may radiate high beam or light constituting an image. When the vehicle lamp irradiates high beam, the light of the light distribution pattern PH of the high beam, which is the light distribution pattern for night illumination shown in fig. 14 (B), is irradiated. In the high beam light distribution pattern PH of fig. 14 (B), the region PHA1 is the region having the highest intensity, and the region PHA2 is the region having the 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. In addition, the phase modulation element 54S of the third embodiment diffracts light so that the light synthesized due to the afterimage phenomenon forms a light distribution pattern including the intensity distribution of the high beam. In the case where 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 reflection type phase modulation elements. However, as the phase modulation element, for example, an LCD (Liquid CRYSTAL DISPLAY) which is a Liquid crystal panel, 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, like 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 the light emitted from each point is adjusted, so that the light distribution pattern of the emitted light can be made to be a desired light distribution pattern. In addition, the pair of electrodes are not transparent electrodes. Further, GLV is a reflective phase modulation element. The GLV diffracts incident light by deflection of the electrically controlled reflector, and outputs the diffracted light, and the light distribution pattern of the outputted light is a desired light distribution pattern.
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, 54B may be juxtaposed in the longitudinal direction or may be juxtaposed in the longitudinal direction and the transverse 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 155s. However, the light guide optical system 155 is not limited to the configuration of the first and third embodiments described above, as long as the light LR, LG, and LB emitted from the light emitting optical systems 51R, 51G, and 51B is guided to the phase modulation element assembly 54 and the phase modulation element 54S. For example, the light guiding optical system 155 may not have the reflecting mirror 155m. 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 band and reflect light in other wavelength bands may be used for the first and second optical elements 155f and 155s.
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 assembly 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 is incident on the phase modulation element assembly 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 with 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, third light DLB and second light DLG may be combined in first optical element 55f, and third light DLB and second light DLG combined in first optical element 55f may be combined with first light DLR in second optical element 55s. In this case, in the second embodiment, the positions of the first light source 52R, the first collimator lens 53R, the first phase modulation element 54R, the third light source 52B, the third collimator 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 55s. In the second embodiment, the combining optical system 55 may combine the light DLR, DLG, DLB emitted from the respective phase modulation elements 54R, 54G, 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 synthetic optical system 55. In this case, as in the first embodiment, the respective phase modulation elements 54R, 54G, and 54B diffract the incident light LR, LG, and LB so that the light DLR, DLG, DLB emitted from the respective phase modulation elements 54R, 54G, and 54B is combined.
In the first embodiment, the optical system unit 50 does not include a combining optical system for combining 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 synthetic 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-described embodiment, the lamp unit 20 does not have an imaging lens system including an imaging lens. The lamp unit 20 may have an imaging lens system through which the 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 is easily obtained. Here, the term "wide" means a wide area when compared with a light distribution pattern formed on a vertical surface at a predetermined distance from the vehicle.
In the above embodiment, the incident points SR, SG, SB have a substantially elliptical shape. However, the shape of the incident points SR, SG, SB is not particularly limited, and may be, for example, a circular shape.
In the above embodiment, the phase modulation elements 54R, 54G, 54B, and 54S have a substantially rectangular shape, and the incident surfaces have a substantially rectangular shape. However, the shape of the incident surface of the phase modulation element 54R, 54G, 54B, 54S may be a shape having a width in the vertical direction larger than a 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 among the plurality of phase modulation elements may be connected to at least one other phase modulation element and integrally formed with the other phase modulation element.
In the third embodiment, among the three light sources 52R, 52G, 52B, each of the light sources 52R, 52G, 52B alternately emits light. However, from the viewpoint of reduction in the number of components and downsizing, it is sufficient to alternately emit light from each of at least two light sources. In this case, light emitted from the phase modulation element into which light emitted from at least two light sources is incident is combined by an afterimage phenomenon, and light combined by the afterimage phenomenon is combined with light emitted from another phase modulation element, thereby irradiating 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, 52B and the three phase modulation elements 54R, 54G, 54B are integrated to emit laser light in different wavelength bands is described as an example. In the second embodiment, the optical system unit 50 having the three light sources 52R, 52G, and 52B emitting the laser light in the 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 one to one is described as an example. In the third embodiment, the optical system unit 50 having the three light sources 52R, 52G, 52B emitting the laser light in the 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 the white laser light emitted from the light source and emits the light. 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, light combined with light emitted from a plurality of 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 usable in the field of vehicle lamps such as automobiles.
(Third aspect)
Hereinafter, a mode for implementing the vehicle lamp of the present invention is illustrated together with the drawings. The following exemplary embodiments are provided for ease of understanding 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 gist of the present invention.
(First embodiment)
Fig. 17 is a view schematically showing a cross section in the vertical direction of the vehicle lamp according to the present embodiment. The vehicle lamp of the present embodiment is a headlight 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 substantially symmetrical in the left and right directions. Therefore, in the present embodiment, one of the headlamps will be described. As shown in fig. 17, the headlamp 1 of the present embodiment has a frame 10 and a lamp unit 20 as main configurations.
The housing 10 has a lamp housing 11, a front cover 12, and a rear cover 13 as main structures. The front opening of the lamp housing 11 is closed, and the front cover 12 is fixed to 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.
The space formed by the lamp housing 11, the front cover 12 closing the front opening of the lamp housing 11, and the rear cover 13 closing the rear opening of the lamp housing 11 is a lamp room R, and the lamp unit 20 is housed in the lamp room R.
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.
The heat sink 30 has a metal bottom plate 31 extending in a substantially horizontal direction, and a plurality of heat radiating fins 32 are integrally provided with the bottom plate 31 on a lower surface side of the bottom plate 31. The cooling fan 35 is disposed with a gap from the heat radiating fins 32, and is fixed to the heat sink 30. The radiator 30 is cooled by the air flow generated by the rotation of the cooling fan 35. 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 has a substantially rectangular shape and is made of a metal such as aluminum. An optical system unit 50 is housed in the 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 make the inner wall of the cover 40 light-absorbing, it is preferable to perform a black alumina film process or the like on the inner wall. By making the inner walls of the cover 40 light-absorbing, even when light is irradiated to these inner walls by unexpected reflection, or the like, reflection of the irradiated light can be suppressed and emitted from the opening 40H in unexpected directions.
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 guiding optical system 155, and a phase modulation element assembly 54 formed by unitizing a plurality of phase modulation elements.
The first light-emitting optical system 51R includes a first light source 52R and a first collimating lens 53R. The first light source 52R is a laser device that emits laser light in a predetermined wavelength band, and in the present embodiment, is a semiconductor laser that emits laser light having a peak wavelength of power of, for example, 638nm, which is red. The optical system unit 50 has 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 fast axis direction and the slow axis direction of the laser beam emitted from the first light source 52R. 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 collimator lens 53R, a collimator lens for collimating the fast axis direction of the laser light and a collimator lens for collimating the slow axis direction may be provided.
The second light-emitting optical system 51G has a second light source 52G and a second collimator lens 53G, and the third light-emitting optical system 51B has a third light source 52B and a third collimator lens 53B. The light sources 52G and 52B are laser elements that emit laser light in a predetermined wavelength band, respectively. In the present embodiment, the second light source 52G is a semiconductor laser that emits green laser light having a peak wavelength of, for example, 515nm, and the third light source 52B is a semiconductor laser that emits blue laser light having a peak wavelength of, for example, 445 nm. Therefore, in the present embodiment, the three light sources 52R, 52G, 52B emit laser light in predetermined wavelength bands different from each other. These light sources 52G and 52B are mounted on the circuit board, respectively, similarly to the first light source 52R.
The second collimator lens 53G collimates 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 collimates 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 these collimator lenses 53G and 53B, a collimator lens for collimating the fast axis direction of the laser light and a collimator lens for collimating 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 reflecting mirror 155m, a first optical element 155f, and a second optical element 155s. The 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 mirror 155m, and reflects the light LG emitted from the second light-emitting 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 such a first optical element 155f and a second optical element 155s, a wavelength selective filter in which an oxide film is laminated on a glass substrate can be exemplified. 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 combine the light rays LR, LG, and LB, but emits the light rays LR, LG, and LB in parallel in the front-rear direction, and enters the phase modulation element assembly 54. In fig. 18, light LR is indicated by a solid line, light LG is indicated by a broken line, and light LB is indicated by a one-dot chain line.
The phase modulation element assembly 54 diffracts the 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 is incident is inclined at approximately 45 degrees with respect to the vertical direction, and the light LR, LG, LB emitted from the light guide optical system 155 is incident on 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 emitting 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 emitting optical system 51G. In addition, 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 assembly 54 includes: the phase modulation element diffracts the light LR from the first light emitting optical system 51R to form the light LR into a predetermined light distribution pattern, the phase modulation element diffracts the light LG from the second light emitting optical system 51G to form the light LG into a predetermined light distribution pattern, and the phase modulation element 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 aligned in one direction, and the incidence surface EF of the phase modulation element assembly 54 is formed by the incidence surface of the light of these phase modulation elements.
In the present embodiment, the three phase modulation elements are reflective phase modulation elements that diffract incident light while reflecting the light, and are each emitted, specifically, reflective LCOS (Liquid Crystal On Silicon: liquid crystal silicon on device). Therefore, the phase modulation element assembly 54 diffracts the first light DLR that diffracts the red light LR, the second light DLG that diffracts the green light LG, and the third light DLB that diffracts the blue light LB by the phase modulation elements corresponding to the light LR, LG, and LB incident on the incident surface EF, and emits the light beams from the incident surface EF. The light DLR, DLG, DLB emitted from the phase modulation element assembly 54 in this way is emitted from the optical system unit 50. In fig. 17 and 18, first light DLR is indicated by a solid line, second light DLG is indicated by a broken line, and third light DLB is indicated by a one-dot chain line. In fig. 17, these lights DLR, DLG, DLB are shown in a staggered manner.
Next, the structure of the phase modulation element assembly 54 according to 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 as 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 a main view, and the entire area in the main 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 elongated in the vertical direction. In the following description, in a front view of the phase modulation element assembly 54, a direction parallel to the horizontal direction is a lateral direction, and a direction perpendicular to the lateral direction is a longitudinal direction. Therefore, the lateral direction is a direction parallel to the horizontal direction, the longitudinal direction is a direction parallel to the direction in which the vertical direction is projected onto 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 emitting optical system 51R, a second phase modulation element 54G corresponding to the second light emitting optical system 51G, and a third phase modulation element 54B corresponding to the third light emitting 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 longitudinal direction of the phase modulation element assembly 54. Through the drive circuit 60R, electric power is supplied to the phase modulation elements 54R, 54G, and 54B constituting the phase modulation element assembly 54, respectively.
The width of the first phase modulation element 54R in the lateral direction, the width of the second phase modulation element 54G in the lateral direction, and the width of the third phase modulation element 54B in the lateral direction are the same as the width W54 of the phase modulation element aggregate 54 in the lateral direction. 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 transverse direction of the phase modulation element aggregate 54. That is, the phase modulation elements 54R, 54G, 54B are formed in a substantially rectangular shape elongated in the horizontal direction, that is, in the lateral direction. As described above, the entire area of the phase modulation element assembly 54 in the main 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 beams of the phase modulation elements 54R, 54G, and 54B, so that the incident surfaces of the light beams of the phase modulation elements 54R, 54G, and 54B are each formed in a substantially rectangular shape elongated in the horizontal direction, that is, 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 juxtaposed. Therefore, the longitudinal direction of each of the light incident surfaces of the phase modulation elements 54R, 54G, 54B is substantially perpendicular to the longitudinal direction. In the present embodiment, 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 substantially the same. Therefore, the longitudinal widths of the light incident surfaces of the phase modulation elements 54R, 54G, and 54B are substantially the same.
The first phase modulation element 54R has a plurality of modulation units MPR arranged in a matrix. The second phase modulation element 54G has a plurality of modulation units MPG arranged in a matrix, and the third phase modulation element 54B has a plurality of modulation units MPB arranged in a matrix. In this embodiment, these modulation units MPR, MPG, MPB have square shapes of the same size. Therefore, the number of modulation sections MPR juxtaposed in the longitudinal direction of the incident surface of the first phase modulation element 54R is larger than the number of modulation sections MPR juxtaposed in the direction perpendicular to the longitudinal direction of the incident surface of the phase modulation element 54R. The number of modulation units MPG aligned in the longitudinal direction of the incident surface of the second phase modulation element 54G is larger than the number of modulation units MPG aligned in the direction perpendicular to the longitudinal direction of the incident surface of the second phase modulation element 54G, and the number of modulation units MPB aligned in the longitudinal direction of the incident surface of the third phase modulation element 54B is larger than the number of modulation units MPB aligned in the direction perpendicular to the longitudinal direction of the incident surface of the third phase modulation element 54B. Each of the modulation units MPR, MPG, MPB includes a plurality of dots arranged in a matrix, and diffracts and emits light incident on the modulation unit MPR, MPG, 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 diffracted by the light LG. 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 third light DLB diffracted by the blue light LB.
Fig. 19 shows an incidence point SR, which is a region where red light LR is irradiated, an incidence point SG, which is a region where green light LG is irradiated, and an incidence point SB, which is a region where blue light LB is irradiated. In the present embodiment, as described above, the light sources 52R, 52G, 52B are semiconductor lasers, and therefore, the lasers emitted from the light sources 52R, 52G, 52B propagate while expanding in a substantially elliptical shape. The laser beams emitted from the light sources 52R, 52G, and 52B are collimated by the collimator lenses 53R, 53G, and 53B in the fast axis direction and the slow axis direction, 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 assembly 54 via the light guiding optical system 155. In the present embodiment, in the light guide optical system 155, the shapes of the light rays LR, LG, and LB are not adjusted, and therefore the shapes of the incident points SR, SG, and SB are substantially elliptical.
In the present embodiment, the size of the incidence point SR having a substantially elliptical shape is such that it can include at least one modulation unit MPR, and the long axis LAR of the incidence point SR is substantially parallel to the longitudinal direction, that is, the lateral direction of the incidence plane of the first phase modulation element 54R. In other words, the incident point SR has a substantially elliptical shape elongated 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 incidence point SG having a substantially elliptical shape is a size including at least one modulation unit MPG, and the major axis LAG of the incidence point SG is substantially parallel to the longitudinal direction, that is, the lateral direction of the incidence plane 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 substantially elliptical incidence point SB may include the size of at least one modulation unit MPB, and the major axis LAB of the incidence point SB may be substantially parallel to the longitudinal direction, that is, the lateral direction of the incidence plane 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 modulation element 54B.
In the present embodiment, the width in the longitudinal direction, which is the direction perpendicular to the longitudinal direction of the incident point SR, the width in the longitudinal direction, which is the direction perpendicular to the longitudinal direction of the incident point SG, and the width in the longitudinal direction, which is the direction perpendicular to the longitudinal direction of the incident point SB, are substantially the same. The width of the incident point SR in the longitudinal direction, i.e., the lateral direction, the width of the incident point SG in the longitudinal direction, i.e., the lateral direction, and the width of the incident point SB in the longitudinal direction, i.e., the lateral direction, are substantially the same. In addition, the widths of the incident points SR, SG, SB may also be different from each other.
Fig. 20 is a diagram 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 silicon substrate 62, a drive circuit layer 63, a plurality of electrodes 64, a reflective film 65, a liquid crystal layer 66, a transparent electrode 67, and a light-transmitting substrate 68 as main components.
The plurality of electrodes 64 are arranged in a matrix on one surface side of the silicon substrate 62 so as to correspond to the respective points in one-to-one correspondence. 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 light-transmitting substrate 68 is disposed opposite to the silicon substrate 62 on one side of the silicon substrate 62, and is, for example, a glass substrate. The transparent electrode 67 is disposed on the surface of the transparent 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 is incident from the incident surface EF on the opposite side of the light transmissive substrate 68 from the silicon substrate 62 side.
As shown in fig. 20, light RL incident from an incident surface EF on the opposite side of the silicon substrate 62 side of the light-transmitting 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 light-transmitting substrate 68. When a voltage is applied between the 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. According to the change in alignment of the liquid crystal molecules 66a, the reflectance of the liquid crystal layer 66 located between the electrode 64 and the transparent electrode 67 changes, and the optical path length of the light RL transmitted through the liquid crystal layer 66 changes. Therefore, by transmitting the light RL through the liquid crystal layer 66 and emitting the light RL 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 each modulator MPR, MPG, MPB, the alignment of the liquid crystal molecules 66a can be changed by controlling the voltage applied between the electrode 64 and the transparent electrode 67 corresponding to each point DT, and the amount of change in the phase of the light emitted from each point DT can be adjusted according to each point DT. Since the light having different phases interfere with each other and diffract, the light emitted from the point DT interferes and diffracts, and the diffracted light is emitted from the phase modulation element assembly 54. Therefore, the phase modulation element assembly 54 can diffract the incident light and emit the 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 area where 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 on each modulation section MPR of the first phase modulation element 54R of the phase modulation element assembly 54. The same phase modulation pattern is formed on each modulation section MPG of the second phase modulation element 54G, and the same phase modulation pattern is formed on each modulation section MPB of the third phase modulation element 54B. In this specification, the phase modulation pattern means a pattern that modulates 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 the 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 set to a desired light distribution pattern. In the present embodiment, the respective phase modulation patterns of the modulation unit MPR, MPG, MPB are different from each other.
Specifically, in the present embodiment, the respective phase modulation patterns of the modulator MPR, MPG, MPB are phase modulation patterns that diffract the light LR, LG, and LB, respectively, so that the light combined by 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 the low beam. In other words, the phase modulation elements 54R, 54G, 54B of the phase modulation element assembly 54 diffract the incident light LR, LG, LB, respectively, so that the light that is synthesized by the light DLR, DLG, DLB emitted from the phase modulation elements 54R, 54G, 54B, respectively, 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 with and is based on the intensity distribution of the light distribution pattern of the low beam. Third light DLB emitted from third phase modulation element 54B is an intensity distribution that coincides 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. As described above, the phase modulation elements 54R, 54G, and 54B have the plurality of modulation portions MPR, MPG, MPB forming the same phase modulation pattern, and diffract the light LR, LG, and LB, respectively, so that the respective modulation portions MPR, MPG, MPB become the light distribution patterns. The phase modulation elements 54R, 54G, and 54B preferably diffract the incident light LR, LG, and LB so that the outer shape of the light distribution pattern of the light DLR, DLG, DLB emitted from the phase modulation elements 54R, 54G, and 54B matches the outer shape of the light distribution pattern of the low beam. Thus, the first phase modulation element 54R emits light DLR of the red component of the light distribution pattern of the low beam, the second phase modulation element 54G emits light DLG of the green component of the light distribution pattern of the low beam, and the third phase modulation element 54B emits light DLB of the blue component of the light distribution pattern of the low beam.
Next, emission of light from the headlight 1 will be described. Specifically, a case where a low beam is emitted from the headlight 1 will be described.
By supplying power to the light sources 52R, 52G, and 52B from a power source not shown, 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 lasers 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, LB emitted from the light-emitting optical systems 51R, 51G, 51B enters the light-guiding optical system 155.
In the light guide optical system 155, the light LR from the first light emitting optical system 51R is reflected by the reflecting 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. In this way, 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 guiding 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 exits from the light-guiding optical system 155. In this way, 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 guiding optical system 155. The light LB from the third light emitting optical system 51B is reflected by the second optical element 155s and emitted from the light guide optical system 155. The light LB emitted from the light guide optical system 155 in this way 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 modulation element 54B of the phase modulation element assembly 54 by the light guiding 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, and emits the first light DLR, which is the light of the red component of the light distribution pattern of the 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 light of the green component of the light distribution pattern of the near light. The third phase modulation element 54B diffracts the light LB incident on the third phase modulation element 54B, and emits third light DLB, which is light of the blue component of the low beam light distribution pattern. In this way, the lights DLR, DLG, DLB emitted from the phase modulation element assembly 54 are respectively irradiated to the outside of the headlamp 1 through the front cover 12. At this time, the light DLR, DLG, DLB is irradiated at a focal position at a predetermined distance from the vehicle so that the areas where the respective lights are irradiated 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, DLB is a light distribution pattern of low beam, the irradiated light is low beam. The light DLR, DLG, DLB is preferably configured to have substantially uniform outer shapes of the respective light distribution patterns at the focal positions.
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 of low beam, and fig. 21 (B) is a view showing a light distribution pattern of high beam. In fig. 21, S represents a horizontal line, and a light distribution pattern is represented by a thick line. The area PLA1 in the light distribution pattern PL of the low beam, which is the light distribution pattern for night illumination shown in fig. 21 (a), is the area with the highest intensity, and the intensity is reduced in the order of the areas PLA2 and PLA 3. That is, the phase modulation elements 54R, 54G, and 54B of the phase modulation element assembly 54 diffract the light so that the combined light forms a light distribution pattern including the intensity distribution of the low beam. In fig. 21, as shown by a broken line, light having a lower intensity than the low beam may be irradiated from the head lamp 1 above a position where the low beam is irradiated. The light is the light OHS for identification. In this case, the light DLR, DLG, DLB emitted from the respective phase modulation elements 54R, 54G, 54B of the phase modulation element assembly 54 preferably includes the identification light OHS. In this case, it can be understood that a light distribution pattern for night illumination is formed by using the low beam and the sign recognition light OHS. The light distribution pattern for night illumination is used not only at night but also in a dark place such as a tunnel.
As described above, the headlamp 1 of the present embodiment includes: light sources 52R, 52G, 52B that emit light; a phase modulation element assembly 54 having 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 has a plurality of modulation portions MPR that diffract the light LR from the first light source 52R to form the light LR into a predetermined light distribution pattern. The second phase modulation element 54G has a plurality of modulation portions MPG that diffract the light LG from the second light source 52G to form the light LG into a predetermined light distribution pattern. The third phase modulation element 54B has a plurality of modulation portions MPB that diffract the light LB from the third light source 52B to form the light LB into 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 substantially rectangular 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 substantially elliptical in shape elongated in the lateral direction. The size of the incident point SR is a size that can include at least one modulation unit MPR, the size of the incident point SG is a size that can include at least one modulation unit MPG, and the size of the incident point SB is a size that can include at least one modulation unit MPB. The long-side direction of the incident surface of the first phase modulation element 54R is not perpendicular to the long-side direction of the incident point SR, the long-side direction of the incident surface of the second phase modulation element 54G is not perpendicular to the long-side direction of the incident point SG, and the long-side direction of the incident surface of the third phase modulation element 54B is not perpendicular to the long-side 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 modulation unit MPR, the light LG from the second light source 52G can be incident on at least one modulation unit MPG, and the light LB from the third light source 52B can be incident on at least one modulation unit MPB. Therefore, the light distribution pattern PL of the low beam can be formed by the modulation portions MPR, MPG, 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 substantially rectangular in 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 long-side direction of the incident surface of the first phase modulation element 54R is not perpendicular to the long-side direction of the incident point SR, the long-side direction of the incident surface of the second phase modulation element 54G is not perpendicular to the long-side direction of the incident point SG, and the long-side direction of the incident surface of the third phase modulation element 54B is not perpendicular to the long-side direction of the incident point SB. Therefore, 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, 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 even without adjusting the shape of the light LR from the first light source 52R. In addition, in the headlamp 1 of the present embodiment, even if the shape of the light LG from the second light source 52G is not adjusted, it is possible to suppress the exposure of a part of the incident point SG from the incident surface of the second phase modulation element 54G, 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, it is possible to suppress the exposure of a part of the incident point SB from the incident surface of the third phase modulation element 54B, even if the shape of the light LB from the third light source 52B is not adjusted, 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 according to the present embodiment can suppress a decrease in energy efficiency and a large size.
In the headlamp 1 of 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 of 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. In addition, it is possible to further suppress the exposure of a part of the incident point SG from the incident surface of the second phase modulation element 54G, and to further suppress the exposure of a part of the incident point SB from the incident surface of the third phase modulation element 54B.
The headlamp 1 of the present embodiment includes a plurality of light sources 52R, 52G, 52B, and the phase modulation element assembly 54 includes: the first phase modulation element 54R into which the light LR from the first light source 52R is incident, the second phase modulation element 54G into which the light LG from the second light source 52G is incident, and the third phase modulation element 54B into which the light LB from the third light source 52B is incident. That is, the phase modulation elements 54R, 54G, 54B of the phase modulation element aggregate 54 are provided on the light sources 52R, 52G, 52B for each light source. The phase modulation element assembly 54 is formed by integrally forming the phase modulation elements 54R, 54G, and 54B in such a manner that the first phase modulation element 54R and the third phase modulation element 54B are connected to the second phase modulation element 54G. 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.
(Second embodiment)
Next, a second embodiment of the present invention will be described in detail with reference to fig. 22 and 23. The same or equivalent components as those of the first embodiment are denoted by the same reference numerals unless otherwise specified, and overlapping description thereof is omitted.
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 from the front side, i.e., the opening 40H side of the cover 40, and in fig. 22, 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 for ease of understanding. As shown in fig. 22, the optical system unit 50 of the present embodiment is mainly different from the optical system unit 50 of the first embodiment 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 so that the incident surface EF of the incident light is inclined at approximately 45 degrees with respect to the vertical direction, and the light emitting optical systems 51R, 51G, 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 directly enter the phase modulation element assembly 54, respectively. In the present embodiment, the light sources 52R, 52G, 52B are juxtaposed in the left-right direction, and the light emitting optical systems 51R, 51G, 51B including the light sources 52R, 52G, 52B are juxtaposed 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 as viewed from the incident surface EF side on which light is incident, and fig. 23 schematically shows the phase modulation element assembly 54. As shown in fig. 23, the phase modulation element assembly 54 of the present embodiment differs from the phase modulation element assembly 54 of the first embodiment in that three phase modulation elements 54R, 54G, 54B are arranged adjacently and in different directions.
Specifically, the phase modulation element assembly 54 of the present embodiment is formed in a substantially rectangular shape elongated in the left-right direction, that is, in the lateral direction in a main view. The three phase modulation elements 54R, 54G, 54B are juxtaposed in a 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. These phase modulation elements 54R, 54G, 54B are each substantially rectangular in shape elongated in the lateral direction, and the incident points SR, SG, SB are each substantially elliptical in shape elongated in the lateral direction, as in the first embodiment. 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, 54B is substantially parallel to the lateral direction, which is the direction in which the phase modulation elements 54R, 54G, 54B are juxtaposed.
As in the first embodiment, the headlamp 1 of the present embodiment can suppress exposure of a part of the incident point SR from the incident surface of the first phase modulation element 54R even without adjusting the shape of the light LR from the first light source 52R, 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. In addition, in the headlamp 1 of the present embodiment, even if the shape of the light LG from the second light source 52G is not adjusted, it is possible to suppress the exposure of a part of the incident point SG from the incident surface of the second phase modulation element 54G, 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, it is possible to suppress the exposure of a part of the incident point SB from the incident surface of the third phase modulation element 54B, even if the shape of the light LB from the third light source 52B is not adjusted, 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 according to the present embodiment can suppress a decrease in energy efficiency and a large size.
In the headlamp 1 of the present embodiment, the three phase modulation elements 54R, 54G, 54B are adjacently arranged in the left-right direction, that is, in the lateral direction. The light sources 52R, 52G, 52B are aligned in the right-left direction in correspondence with the phase modulation elements 54R, 54G, 54B, and the light from the light sources 52R, 52G, 52B is incident on the phase modulation element assembly 54 without passing through the light guide optical system 155. Therefore, the headlamp 1 according to the present embodiment can have a simple structure as compared with a case where the light guide optical system 155 is not provided. In the headlamp 1 according to the present embodiment, the longitudinal direction of the incident surface of the phase modulation elements 54R, 54G, 54B is substantially parallel to the lateral direction, which is the direction in which the phase modulation elements 54R, 54G, 54B are aligned. Therefore, compared with the case where the directions of the long sides of the incident surfaces of the adjacent parallel phase modulation elements 54R, 54G, 54B are perpendicular to the directions in which the phase modulation elements 54R, 54G, 54B are parallel, 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 are increased. 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 respective longitudinal directions of the incident surfaces of the adjacent parallel phase modulation elements 54R, 54G, 54B are perpendicular to the parallel directions of these phase modulation elements 54R, 54G, 54B. Therefore, the headlamp 1 of the present embodiment can further increase the light sources 52R, 52G, 52B compared to the case where the respective longitudinal directions of the incident surfaces of the adjacent parallel phase modulating elements 54R, 54G, 54B are perpendicular to the direction in which these phase modulating elements 54R, 54G, 54B are parallel. 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, 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. The same or equivalent components as those of the first embodiment are denoted by the same reference numerals unless otherwise specified, and overlapping description thereof is omitted.
Fig. 24 is a view showing an optical system unit according to a third embodiment of the present invention, similar 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 the combining optical system 55 is provided instead of the light guiding optical system 155.
The phase modulation elements 54R, 54G, and 54B of the present embodiment are LCOS, as in 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 view 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 lateral direction is larger than the width of the incident surface EFR of the first phase modulation element 54R in the longitudinal direction. The first phase modulation element 54R has 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 greater 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 which is the semiconductor laser is not adjusted, the shape of the incident point SR of the first phase modulation element 54R is a substantially elliptical shape. In the present embodiment, as in the first embodiment, the size of the substantially elliptical incidence point SR is such that at least one modulation section MPR can be included, and the long axis LAR of the incidence point SR is substantially parallel to the longitudinal direction of the incidence plane 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 view of the incident surface EFG side 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 has a plurality of modulation units MPG arranged in a matrix, and the number of modulation units MPG aligned in the longitudinal direction of the incident surface EFG of the second phase modulation element 54G is larger than the number of modulation units MPG aligned 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 that 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 that is the semiconductor laser is not adjusted, the shape of the incidence 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 substantially elliptical incidence point SG is such that at least one modulation section MPG can be included, and the long axis LAG of the incidence point SG is substantially parallel to the longitudinal direction of the incidence plane EFG of the second phase modulation element 54G.
The third phase modulation element 54B of the present embodiment is formed in a substantially rectangular shape elongated in the lateral direction when viewed from the side of the incident surface EFB on which light is incident. Therefore, the width of the incident surface EFB of the third phase modulation element 54B in the lateral direction is larger than the width of the incident surface EFB of the third phase modulation element 54B in the longitudinal direction. The third phase modulation element 54B has a plurality of modulation units MPB arranged in a matrix, and the number of modulation units 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 units MPB arranged in the direction perpendicular to the longitudinal direction of the incident surface EFB of the third phase modulation element 54B. 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, the shape of the light LB from the third light source 52B, which is the semiconductor laser, is not adjusted, and therefore the shape of the incident point SB of the phase modulation element 54B is a substantially elliptical shape. In the present embodiment, as in the first embodiment, the size of the substantially elliptical incidence point SB is such that at least one modulation section MPB can be included, and the long axis LAB of the incidence point SB is substantially parallel to the long-side direction of the incidence plane 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 55s. 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, first optical element 55f synthesizes first light DLR and second light DLG by transmitting first light DLR and reflecting second light DLG. The second optical element 55s is an optical element for combining the first light DLR and the second light DLG combined by the first optical element 55f with the third light DLB emitted from the third phase modulation 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 first optical element 55f and second optical element 55s, a wavelength selective filter in which an oxide film is laminated on a glass substrate can be exemplified. 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, in the combining optical system 55, the first light DLR, the second light DLG, and the third light DLB are combined, and the light is emitted from the combining optical system 55. In fig. 24, first light DLR is indicated by a solid line, second light DLG is indicated by a broken line, third light DLB is indicated by a one-dot chain line, and these lights DLR, DLG, DLB are indicated by a shift.
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 so that the light DLR, DLG, DLB emitted from the phase modulation elements 54R, 54G, and 54B, respectively, is a light distribution pattern PL of low beam after being combined by the combining optical system 55. Therefore, the first light DLR, which is the red component light of the low-beam light distribution pattern PL, is emitted from the first phase modulation element 54R, the second light DLG, which is the green component light of the low-beam light distribution pattern PL, is emitted from the second phase modulation element 54G, and the third light DLB, which is the blue component light of the low-beam light distribution pattern PL, is emitted from the third phase modulation element 54B.
In this way, the light DLR, DLG, DLB is 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, even if the shape of the light LR from the first light source 52R is not adjusted, 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. In addition, in the headlamp 1 of the present embodiment, even if the shape of the light LG from the second light source 52G is not adjusted, it is possible to suppress the exposure of a part of the incident point SG from the incident surface EFG of the second phase modulation element 54G, 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, it is possible to suppress the exposure of a part of the incident point SB from the incident surface EFB of the third phase modulation element 54B, even if the shape of the light LB from the third light source 52B is not adjusted, 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 SB. Therefore, the headlamp 1 pump dog according to the present embodiment can suppress a decrease in energy efficiency and a large size.
(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described in detail with reference to fig. 25. The same or equivalent components as those of the first embodiment are denoted by the same reference numerals unless otherwise specified, and overlapping description thereof is omitted.
Fig. 25 is a view showing an optical system unit according to a fourth embodiment of the present invention, similar 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 it has one phase modulation element 54S 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 view 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 has a plurality of modulation portions arranged in a matrix, and the number of modulation portions aligned in the longitudinal direction of the incident surface EFS of the phase modulation element 54S is greater than the number of modulation portions aligned 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 guiding optical system 155 and is incident on the phase modulation element 54S, as in the first embodiment described above. Therefore, the incidence of these lights LR, LG, and LB on the phase modulation element 54S will be described below with reference to fig. 18. In the present embodiment, the power supplied to the light sources 52R, 52G, 52B is adjusted, laser light is alternately emitted to each of the light sources 52R, 52G, 52B, and light LR, LG, LB is alternately emitted to each of the light emitting optical systems 51R, 51G, 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 and 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 and 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 and LG. The emission of the laser light from each of the light sources 52R, 52G, 52B is sequentially switched, and the emission of the light LR, LG, LB from each of the light-emitting optical systems 51R, 51G, 51B is sequentially switched. Accordingly, the light LR, LG, and LB emitted from these light-emitting optical systems 51R, 51G, and 51B, which are different in wavelength band from each other, sequentially enter the phase modulation element 54S. The phase modulation element 54S sequentially emits light DLR, DLG, DLB obtained by diffracting the incident light LR, LG, and LB. In fig. 25, these lights DLR, DLG, DLB are shown in a staggered manner.
In the present embodiment, as in the first embodiment, since the shapes of the light LR, LG, and LB from the light sources 52R, 52G, and 52B that are semiconductor lasers are not adjusted, the shapes of the incident points of these light LR, LG, and LB of the phase modulation element 54S are substantially elliptical. In the present embodiment, the size of each of these substantially elliptical incidence points is such that at least one modulation section can be included, and the long axis of each of these incidence points is substantially parallel to the longitudinal direction of the incidence plane EFS of the phase modulation element 54S. In addition, these incident points coincide with each other.
Next, light emitted from the phase modulation element 54S of the present embodiment will be described. Specifically, a case where the headlight 1 emits light of the low beam light distribution pattern PL 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 light LR from light source 52R is incident, phase modulation element 54S forms a phase modulation pattern corresponding to light source 52R, that is, a phase modulation pattern in which first light DLR emitted from phase modulation element 54S forms the red component light of the low-beam light distribution pattern. Therefore, when the light LR from the light source 52R is incident, 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 second light DLG emitted from the phase modulation element 54S forms a phase modulation pattern of light of a green component of the light distribution pattern of the low beam. Therefore, when the light LG from the light source 52G is incident, the phase modulation element 54S emits the second light DLG, which is light of the green component of the light distribution pattern of the low beam. When light LB from light source 52B is incident, phase modulation element 54S forms a phase modulation pattern corresponding to light source 52B, that is, a phase modulation pattern in which third light DLB emitted from phase modulation element 54S forms light of a blue component of the light distribution pattern of the low beam. Therefore, when the light LB from the light source 52B is incident, the phase modulation element 54S emits the third light DLB, which is light of the blue component of the low beam light distribution pattern.
That is, the phase modulation element 54S 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, by changing the phase modulation pattern according to the wavelength band of the light LR, LG, LB thus incident. These lights DLR, DLG, DLB are emitted from the openings 40H of the cover 40, respectively, and sequentially irradiate the outside of the headlamp 1 through the front cover 12. At this time, first light DLR, second light DLG, and third light DLB are irradiated at focal positions at a predetermined distance from the vehicle so that the respective light irradiation regions overlap with each other. The focal position is, for example, a position 25m from the vehicle. Further, the first light DLR, the second light DLG, and the third light DLB are preferably irradiated so that the outer shape of the area irradiated with each light DLR, DLG, DLB at the focal position is substantially uniform. In the present embodiment, the lengths of the emission times of the laser beams emitted from the light sources 52R, 52G, and 52B are substantially the same, and therefore the lengths of the emission times of the light DLR, DLG, DLB are also substantially the same.
In addition, when light of different colors is repeatedly irradiated at a period shorter than the time resolution of human vision, the human can recognize that light obtained by combining the light of different colors is irradiated due to an afterimage phenomenon. In the present embodiment, when the time for which the laser light is emitted from the light source 52R is shorter than the time resolution of human vision again after the laser light is emitted from the light source 52R, the light DLR, DLG, DLB emitted from the phase modulation element 54S is repeatedly irradiated with the light DLR of red, the light DLG of green, and the light DLB of blue in a period shorter than the time resolution of human vision, and the light DLR of red, the light DLG of green, and the light DLB of blue are combined by the afterimage phenomenon. As described above, the respective emission times of the light DLR, DLG, DLB are substantially the same, and the intensities of the laser beams emitted from the light sources 52R, 52G, 52B are the same predetermined intensities as those of the first embodiment. Therefore, the color of the light synthesized due to the afterimage phenomenon is the same white as the light synthesized by the light DLR, DLG, DLB of the first embodiment. Further, since the light distribution pattern of the light DLR, DLG, DLB synthesized by the light is the light distribution pattern PL of the low beam, the light distribution pattern of the light DLR, DLG, DLB synthesized by the afterimage phenomenon is also the light distribution pattern PL of the low beam. Thus, the light of the low beam light distribution pattern PL is emitted from the headlight 1.
From the viewpoint of suppressing the flicker perceived by the light synthesized by the afterimage phenomenon, the period of repeatedly emitting the laser light from the light sources 52R, 52G, 52B is preferably 1/15s or less. The time resolution of human vision is approximately 1/30s. In the vehicle lamp, the flicker of light can be suppressed as long as the emission period of light is about 2 times. When the period is 1/30s or less, the time resolution of human vision is substantially exceeded. Therefore, the perceived flickering of light can be further suppressed. In addition, from the viewpoint of further suppressing the perceived flicker of 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 respective incident points of the light LR, LG, LB from the light sources 52R, 52G, 52B. Therefore, in the headlamp 1 of the present embodiment, as in the first embodiment, even if the shapes of the light rays LR, LG, and LB from the light sources 52R, 52G, and 52B are not adjusted, it is possible to suppress that part of the incident points of the light rays LR, LG, and LB are exposed from the incident surface EFS of the phase modulation element 54S, respectively. Therefore, the headlamp 1 according to the present embodiment can suppress a decrease in energy efficiency and a large size. In addition, the headlamp 1 of the present embodiment can make the phase modulation elements for diffracting the light LR, LG, LB from the three light sources 52R, 52G, 52B common phase modulation elements, and therefore can reduce the number of components or miniaturize the device.
The present invention has been described above by way of example of the above embodiments, and the present invention is not limited to this.
The vehicle lamp of the present invention includes: a light source; a phase modulation element having at least one modulation unit for diffracting light from the light source to form the light into 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 with other directions, and the size of the incident point is not particularly limited as long as the long-side direction of the light incident surface of the phase modulation element is not perpendicular to the long-side direction of the incident point, as long as the size of the incident point is capable of including at least one modulation unit. The vehicle lamp thus configured can suppress exposure of a part of the incident point from the incident surface of the phase modulation element, while suppressing reduction in energy efficiency and increase in size, even if the shape of the light from the light source is not adjusted, as compared 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.
In the above embodiment, the headlight 1 as the vehicle lamp irradiates a low beam, and the present invention is not particularly limited. For example, the vehicle lamp may radiate high beam or light constituting an image. When the vehicle lamp irradiates high beam, the light of the light distribution pattern PH of the high beam, which is the light distribution pattern for night illumination shown in fig. 21 (B), is irradiated. In the high beam light distribution pattern PH of fig. 21 (B), the region PHA1 is the region having the highest intensity, and the region PHA2 is the region having the 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. In addition, the phase modulation element 54S of the third embodiment diffracts light so that the light synthesized due to the afterimage phenomenon forms a light distribution pattern including the intensity distribution of the high beam. In the case where 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 reflection type phase modulation elements. However, as the phase modulation element, for example, an LCD (Liquid CRYSTAL DISPLAY) which is a Liquid crystal panel, 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, like 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 the light emitted from each point is adjusted, so that the light distribution pattern of the emitted light can be made to be a desired light distribution pattern. In addition, the pair of electrodes are not transparent electrodes. Further, GLV is a reflective phase modulation element. The GLV diffracts incident light by deflection of the electrically controlled reflector, and outputs the diffracted light, and the light distribution pattern of the outputted light is a desired light distribution pattern.
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 aggregate 54 are arranged adjacently 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 aggregate 54 are arranged adjacently in the lateral direction. However, the direction in which the phase modulation elements 54R, 54G, 54B are juxtaposed is not particularly limited, and may be juxtaposed in the longitudinal direction and the transverse 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 155s. However, the light guide optical system 155 is not limited to the configuration of the first and fourth embodiments described above, as long as the light LR, LG, and LB emitted from the light emitting optical systems 51R, 51G, and 51B is guided to the phase modulation element assembly 54 and the phase modulation element 54S. For example, the light guiding optical system 155 may not have the reflecting mirror 155m. 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 band and reflect light in other wavelength bands may be used for the first and second optical elements 155f and 155s.
In the first and fourth 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 assembly 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 is incident on the phase modulation element assembly 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 with 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, third light DLB and second light DLG may be combined in first optical element 55f, and third light DLB and second light DLG combined in first optical element 55f may be combined with first light DLR in second optical element 55s. In this case, in the third embodiment, the positions of the first light source 52R, the first collimator lens 53R, the first phase modulation element 54R, the third light source 52B, the third collimator 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 55s. In the third embodiment, the combining optical system 55 may combine the light DLR, DLG, DLB emitted from the respective phase modulation elements 54R, 54G, 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 synthetic optical system 55. In this case, as in the first embodiment, the respective phase modulation elements 54R, 54G, and 54B diffract the incident light LR, LG, and LB so that the light DLR, DLG, DLB emitted from the respective phase modulation elements 54R, 54G, and 54B is combined.
In the first and second embodiments, the optical system unit 50 does not include a combining optical system for combining the first light DLR, the second light DLG, and the third light DLB. However, the optical system unit 50 of the first and second embodiments may have a synthetic optical system as in the third 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 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 of the second and third embodiments may have a light guide optical system as in the first embodiment.
In addition, in the above-described embodiment, the lamp unit 20 does not have an imaging lens system including an imaging lens. The lamp unit 20 may have an imaging lens system through which the 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 is easily obtained. Here, the term "wide" means a wide area when compared with a light distribution pattern formed on a vertical surface at a predetermined distance from the vehicle.
In the above embodiment, the incident points SR, SG, SB have a substantially elliptical shape. However, the shape of the incident points SR, SG, SB may be any long shape that is longer in a predetermined direction than in other directions.
In the above embodiment, the phase modulation elements 54R, 54G, 54B, and 54S have a substantially rectangular shape, and the incident surfaces have a substantially rectangular shape. However, the incident surfaces of the phase modulation elements 54R, 54G, 54B, and 54S may be long in shape, which 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, 54S is the horizontal direction, that is, the lateral direction. However, the longitudinal direction of the incident surface of the phase modulation element 54R, 54G, 54B, 54S is not particularly limited, and may be the vertical direction, that is, the longitudinal 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 among the plurality of phase modulation elements may be connected to at least one other phase modulation element and integrally formed with the other phase modulation element.
In the second embodiment, all three phase modulation elements 54R, 54G, 54B are arranged adjacently. However, at least two phase modulation elements may be juxtaposed, and the respective longitudinal directions of the incident surfaces of the juxtaposed at least two phase modulation elements may be parallel to the direction in which the phase modulation elements are juxtaposed. 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, 52B, each of the light sources 52R, 52G, 52B alternately emits light. However, from the viewpoint of reduction in the number of components and downsizing, it is sufficient to alternately emit light from each of at least two light sources. In this case, light emitted from the phase modulation element into which light emitted from at least two light sources is incident is combined by an afterimage phenomenon, and light combined by the afterimage phenomenon is combined with light emitted from another phase modulation element, thereby irradiating 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, 52B and the three phase modulation elements 54R, 54G, 54B are integrated with each other, which emit laser light in different wavelength bands, is described as an example. In the third embodiment, the optical system unit 50 having the three light sources 52R, 52G, and 52B emitting the laser light in the 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 one to one is described as an example. In the fourth embodiment, the optical system unit 50 having the three light sources 52R, 52G, 52B emitting the laser light in the 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 the white laser light emitted from the light source and emits the light. 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, light combined with light emitted from a plurality of light sources may be made incident on one phase modulation element.
Industrial applicability
The present invention provides a vehicle lamp capable of suppressing a decrease in energy efficiency and suppressing an increase in size, 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 illustrated together with the drawings. The following exemplary embodiments are provided for ease of understanding 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 gist of the present invention. In the drawings referred to below, the dimensions of the respective components may be changed for easy understanding.
(First embodiment)
Fig. 26 is a view schematically showing an example of the vehicle lamp according to the present embodiment, and is a vertical cross-sectional view schematically showing a cross-section of the vehicle lamp in the up-down direction. In the present embodiment, the vehicle lamp is a vehicle headlamp 1. As shown in fig. 26, the vehicle headlamp 1 has a housing 10 and a lamp unit 20 as main configurations.
The housing 10 has a lamp housing 11, a front cover 12, and a rear cover 13 as main structures. An opening is formed in 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.
The space formed by the lamp housing 11, the front cover 12 closing the front opening of the lamp housing 11, and the rear cover 13 closing the rear opening of the lamp housing 11 is a lamp room R, and the lamp unit 20 is housed in the lamp room R.
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. The lamp unit 20 is fixed to the housing 10 by a structure not shown. The optical system unit 50 generates desired light, and the light is emitted from the lamp unit 20.
In the present embodiment, the heat sink 30 has a metal bottom plate 31 extending in a substantially front-rear direction, and a plurality of heat radiating fins 32 are integrally provided with the bottom plate 31 on a lower surface side of the bottom plate 31. The cooling fan 35 is disposed with a gap from the heat radiating fins 32, and is fixed to the heat sink 30. The radiator 30 is cooled by the 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 has a substantially rectangular shape and is made of a metal such as aluminum. The optical system unit 50 is housed in a space inside the cover 40. In addition, 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 absorbability by black alumina film processing or the like. By making the inner wall of the cover 40 light-absorbing, unwanted reflection can be suppressed, and light irradiated to the inner wall of the cover 40 by refraction or the like can be 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 has a first light source 52R, a second light source 52G, a third light source 52B, a phase modulation element assembly 54 formed by unitizing a plurality of phase modulation elements, and a light guiding optical system 155 as main configurations. Light emitted from the light sources 52R, 52G, 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 in the lamp room R, respectively, and are fixed to the bottom plate 31 of the heat sink 30 by a structure not shown. In the present embodiment, the light sources 52R, 52G, 52B are disposed in the lamp room R so that the optical path length from the second light source 52G to the phase modulation element assembly 54 is the longest, and the optical path length from the third light source 52B to the phase modulation element assembly 54 is the shortest.
The first light source 52R is a laser element that emits red laser light, and in the present embodiment, the peak wavelength of power emits laser light of 638nm upward, for example. The second light source 52G is a laser element that emits green laser light, and in the present embodiment, the peak wavelength of power emits laser light of 515nm, for example, forward. The third light source 52B is a laser element that emits blue laser light, and in the present embodiment, the peak wavelength of power emits laser light of 445nm, for example, 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. The collimator lenses 53R, 53G, 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 light may be collimated by providing a collimator lens for collimating the fast axis direction and a collimator lens for collimating the slow axis direction of the laser light, respectively.
The light guide optical system 155 includes a first optical element 155f and a second optical element 155s. 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 at about 45 ° with respect to the front-rear direction and the up-down 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 as to transmit light having a wavelength longer than a predetermined wavelength and reflect light having a wavelength shorter than the predetermined wavelength. 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 light emitted from the first collimator lens 53R and the green laser light 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 front-rear direction and the up-down direction in the same direction as the first optical element 155 f. The second optical element 155s is a wavelength selective filter, similar 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 light emitted from the first optical element 155f, the green laser light emitted from the first optical element 155f, and the blue laser light 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 front-rear direction and the up-down direction in the same direction as the optical elements 155f and 155 s. 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 for modulating the phase of the red laser beam so as to form a predetermined light distribution pattern, a second phase modulation element 54G for modulating the phase of the green laser beam so as to form a predetermined light distribution pattern, and a third phase modulation element 54B for modulating the phase of the blue laser beam so as to form a predetermined light distribution pattern, and these phase modulation elements 54R, 54G, and 54B are aligned in one direction.
In the present embodiment, each of the phase modulation elements 54R, 54G, and 54B is a reflective phase modulation element that diffracts incident light while reflecting the light, and specifically, is a reflective LCOS (Liquid Crystal On Silicon: 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, 54B. As shown in fig. 28, the phase modulation element assembly 54 is formed in a substantially rectangular shape in a front view, and includes a first phase modulation element 54R located at the uppermost portion, a second phase modulation element 54G located below the first phase modulation element 54R, and a third phase modulation element 54B located below the second phase modulation element 54G. A drive circuit 60R is electrically connected to the phase modulation element assembly 54. The driving circuit 60R includes a scanning line driving circuit connected to one side of the long side of the phase modulation element assembly 54 and a data line driving circuit connected to one side of the short side of the phase modulation element 54R. Through the drive circuit 60R, electric power is supplied to the phase modulation elements 54R, 54G, and 54B constituting the phase modulation element assembly 54, respectively.
The first phase modulation element 54R is constituted by a plurality of modulation units MPR divided into a matrix. Each modulation unit MPR includes a plurality of dots arranged in a matrix, diffracts incident red laser light while reflecting the same, and emits the diffracted red laser light. The second phase modulation element 54G is constituted by a plurality of modulation units MPG divided into a matrix. Each of the modulation units MPG includes a plurality of dots arranged in a matrix, diffracts incident green laser light while reflecting the incident green laser light, and causes the diffracted green laser light. The third phase modulation element 54B is constituted by a plurality of modulation units MPB divided into a matrix. Each modulation unit MPB includes a plurality of dots arranged in a matrix, diffracts incident blue laser light, and emits the diffracted blue laser light. In fig. 28, the incidence point SR of the red laser light to the first phase modulation element 54R is indicated by a solid line, the incidence point SG of the green laser light to the second phase modulation element 54G is indicated by a broken line, and the incidence point SB of the blue laser light to the third phase modulation element 54B is indicated by a one-dot chain line. In the present embodiment, among the incidence points SR, SG, SB, the incidence point SB of the blue laser light is the largest, and the incidence point SG of the green laser light is the smallest. That is, the longer the optical path length from the light source to the phase modulation element assembly 54 is, the smaller the above-mentioned dot path is. In fig. 28, the incident points SR, SG, SB are represented by circles, and the external shape of the incident points may be other than circles, for example, ellipses.
Fig. 29 is a schematic view 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 silicon substrate 62, a drive circuit layer 63, a plurality of electrodes 64, a reflective film 65, a liquid crystal layer 66, a transparent electrode 67, and a light-transmitting substrate 68 as main structures.
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 opposite to the silicon substrate 62 on one side of the silicon substrate 62, and is, for example, a glass substrate. The transparent electrode 67 is disposed on the surface of the transparent 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 light-transmitting substrate 68 opposite to the silicon substrate 62 side.
As shown in fig. 29, light RL incident from the surface of the light-transmitting substrate 68 opposite to the silicon substrate 62 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 light-transmitting substrate 68. Here, when a voltage is applied between the 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, so that the optical path length of the light RL transmitted through the liquid crystal layer 66 changes. As described above, since the plurality of electrodes 64 are arranged corresponding to the respective points of the modulator MPR, MPG, MPB, the alignment of the liquid crystal molecules 66a at the respective points can be changed by controlling the voltage applied between the electrodes 64 corresponding to the respective points and the transparent electrode 67. Thus, the amount of change in the phase of the light RL emitted from each point is adjusted according to each point, and the respective phase modulation patterns of the modulator MPR, MPG, MPB can be adjusted to predetermined phase modulation patterns.
In the present embodiment, the modulation units MPR of the first phase modulation element 54R each have the same phase modulation pattern corresponding to the red laser light. The modulation units MPG of the second phase modulation element 54G each have the same phase modulation pattern corresponding to the green laser light. The modulation units MPB of the third phase modulation element 54B each have the same phase modulation pattern corresponding to the blue laser light.
In the present embodiment, when the entire incident point SR is incident on the first phase modulation element 54R shown in fig. 28, at least one modulation unit MPR is included in the incident point SR. As described above, since each modulation unit MPR has the same phase modulation pattern, when the entire incident point SR is incident on the first phase modulation element 54R, the light distribution pattern of the red laser light emitted from the first phase modulation element 54R becomes a predetermined light distribution pattern based on the phase modulation pattern of the modulation unit MPR. In the present embodiment, the predetermined light distribution pattern is a light distribution pattern capable of forming a light distribution pattern of low beam. 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, at least one modulation unit MPG is included at the incident point SG. As described above, since each of the modulation units 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 light emitted from the second phase modulation element 54G becomes a predetermined light distribution pattern based on the phase modulation pattern of the modulation unit MPG. In the present embodiment, the predetermined light distribution pattern is a light distribution pattern capable of forming a light distribution pattern of low beam. 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 modulation unit MPB has the same phase modulation pattern, when the entire incident point SB is incident on the third phase modulation element 54B, the light distribution pattern of the blue laser beam emitted from the third phase modulation element 54B becomes a predetermined light distribution pattern based on the phase modulation pattern of the modulation unit MPB. In the present embodiment, the predetermined light distribution pattern is a light distribution pattern capable of forming a light distribution pattern of low beam. Hereinafter, the blue laser light emitted from the phase modulation element assembly 54 may be referred to as third light DLB.
Next, emission of light from the vehicle headlamp 1 will be described. Specifically, a case where a low beam is emitted from the vehicle headlamp 1 will be described.
When power is supplied to the first light source 52R, a red laser beam is generated by the first light source 52R. As shown in fig. 27, the red laser light is emitted upward and collimated by the first collimating lens 53R. When power is supplied to the second light source 52G, green laser light is generated by the second light source 52G, 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, blue laser light is generated by the third light source 52B, and the blue laser light is emitted forward. The blue laser light is collimated by the third collimator lens 53B.
As described above, the red laser light emitted from the first collimating lens 53R passes through the first optical element 155f disposed above the first collimating lens 53R. The green laser light emitted from the second collimator lens 53G is reflected by the first optical element 155f disposed in front of the second collimator lens 53G as described above. That is, the green laser beam is converted to a 90-degree direction by the first optical element 155f and emitted forward. As described above, these red laser light and green laser light are emitted from different positions on the emission surface of the first optical element 155f. Accordingly, 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 light and the green laser light pass through the second optical element 155s disposed above the first optical element 155 f. The blue laser light emitted from the third collimator lens 53B is reflected by the second optical element 155s disposed in front of the third collimator lens 53B as described above. That is, the blue laser light is converted to 90 degrees by the second optical element 155s and emitted forward. As described above, these red laser light, green laser light, and blue laser light are emitted from different positions of the emission surface of the second optical element 155s. Accordingly, the red, green, and blue laser beams emitted from the second optical element 155s propagate upward in a state of being substantially aligned in the front-rear direction. Specifically, among the red laser light, the green laser light, and the blue laser light, the red laser light is located on the forefront side, and the blue laser light is located on the rearrear side.
As described above, in a state where the red laser beam is located on the forefront side and the blue laser beam is located on the rearrear 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 light is incident on 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 light from the second light source 52G to the phase modulation element assembly 54 is longest, and the optical path length of the blue laser light from the third light source 52B to the phase modulation element assembly 54 is 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 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 the low beam. 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 beam. 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 modulation element 54B. As described above, third light DLB becomes a light distribution pattern of low beam.
Thus, the light DLR, DLG, DLB emitted from the phase modulation element assembly 54 is a light distribution pattern of low beam. Therefore, these lights DLR, DLG, DLB are emitted from the opening 40H of the cover 40, and by propagating only a predetermined distance forward, the lights DLR, DLG, DLB are superimposed, whereby the white light, i.e., the low beam PL 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 where the light intensity is maximum, 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, 52B are rocked, the laser beams emitted from the light sources 52R, 52G, 52B also rock, and therefore the incidence points SR, SG, SB may move on the incidence surface of the phase modulation element assembly 54. In this case, when the distance by which the incident point moves is large, the incident point may be exposed to the outside of the phase modulation element assembly 54 or to a different phase modulation element. For example, consider a case where an incidence point of laser light of a predetermined color is exposed to a phase modulation element corresponding to laser light of a different color. 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 that of the low beam with the light emitted from the vehicle headlamp 1, the formation of the low beam PL can be prevented.
When the light source is vibrated as described above, the longer the optical path length to the irradiation position is, the larger the vibration width of the incident point of the light at the irradiation position tends to be. As described above, in the vehicle headlamp 1 according to the present embodiment, the longer the optical path length from the light source to the phase modulation element assembly 54 is, the smaller the above-described dot diameter is, and therefore, as shown in fig. 28, the incident point SG of the green laser light is smaller than the incident points SR, SB. Therefore, even when the incident point SG of the green laser light is greatly moved due to 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 desired light distribution pattern failure such as the low beam PL.
Since the size of the incidence point of each laser beam is different depending on the optical path length to the irradiation position, the 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 incidence point, and an increase in the number of components can be suppressed.
Further, the incidence points SR, SB of the red laser light and the blue laser light having the longer optical path lengths than the green laser light may be set to the same size, and only the size of the incidence point SG may be reduced. That is, of at least two lights having different incident points, the longer the light path length to the phase modulation element is, the smaller the incident point is. As described above, the longer the optical path length from the light source to the phase modulation element assembly 54 is, the smaller the incident point is, and the size of the incident point is set to be the size corresponding to the length of the optical path length, so that a desired light distribution pattern can be more easily obtained.
(Second embodiment)
Next, a second embodiment of the present invention will be described. In addition, the same or equivalent components as those of the first embodiment are denoted by the same reference numerals except for the specific description, and overlapping description thereof is omitted.
Fig. 31 is a view showing a lamp unit 20 of a vehicle headlamp 1 according to a second embodiment of the present invention, similar to fig. 27. In fig. 31, the heat sink 30, the cover 40, and the like of the lamp unit 20 are omitted for easy understanding. As shown in fig. 31, the lamp unit 20 of the second embodiment is different from the lamp unit 20 of the first embodiment in that a phase modulation element 54 is provided for each light source to form a phase modulation element aggregate 54, in that one phase modulation element 54S is provided. The structure of the lamp unit 20 according to the second embodiment will be described below.
In the present embodiment, the first light source 52R emits red laser light upward, the second light source 52G emits green laser light forward, and the third light source 52B emits blue laser light forward. These red laser light, green laser light, and blue laser light are incident on the phase modulation element 54S via the combining optical system 55. The light sources 52R, 52G, 52B are disposed in the lamp room 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 number of total 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 incidence point SG of the green laser light having the longest optical path length to the phase modulation element 54S is smallest, and the incidence point SB of the blue laser light having the shortest optical path length to the phase modulation element 54S is largest. In fig. 32, the incident points SR, SG, SB are represented by circles, and the external shape of the incident points may be other than circles, for example, ellipses.
The light sources 52R, 52G, 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 and 52B during the emission of red laser light from the light source 52R, does not emit light from the light sources 52R and 52B during the emission of green laser light from the light source 52G, and does not emit light from the light sources 52R and 52G during the emission of blue laser light from the light source 52B. That is, the vehicle headlamp 1 of the present embodiment switches the emission of light from the light sources 52R, 52G, 52B at a predetermined cycle 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, 52B are collimated by the collimator lenses 53R, 53G, 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, 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. The 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 passing through the combining optical system 55 can be incident. 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 is the same as the optical elements 55f and 55S.
Next, emission of light from the lamp unit 20 according to the present embodiment will be described. Specifically, a case where a 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, 52B at a predetermined period based on the control of the control system. For example, first, the red laser light is emitted from the first light source 52R for a predetermined time. During this period, the laser light from the light sources 52G, 52B is not emitted. The red laser light is collimated by the collimator lens 53R, and then enters the phase modulation element 54S via the combining optical system 55. As shown in fig. 32, the red laser light enters the incidence plane of the phase modulation element 54S at an incidence point SR having a predetermined size.
When the red laser beam is incident on the phase modulation element 54S, the red laser beam 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 not emitted, and instead of the light emitted 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 via the combining optical system 55. As described above, the green laser light is incident on the incidence surface of the phase modulation element 54S at the incidence point SG smaller than the incidence point SR of the red laser light.
When the green laser beam enters the phase modulation element 54S, the green laser beam 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 the light emitted from the light source 52G, the blue laser light is emitted from the light source 52B for the predetermined time. The blue laser beam is collimated by the collimator lens 53B, and then enters the phase modulation element 54S via the combining optical system 55. As described above, the blue laser light is incident on the incidence surface of the phase modulation element 54S at the incidence point SB larger than the incidence point SR of the red laser light.
When the blue laser beam enters the phase modulation element 54S, the blue laser beam 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.
By the control of the control system, the light emission cycle is repeated at a predetermined period.
In this way, the control system switches the emission of light from the light sources 52R, 52G, 52B at a predetermined cycle, and emits light DLR, DLG, DLB from the vehicle headlamp 1at a predetermined cycle. In the case where the period is shorter than the time resolution of human vision, an afterimage effect is generated, and the human can recognize that light of different colors appears to be synthesized and irradiated. Therefore, by making the period of the present embodiment shorter than the time resolution of a person, the person can recognize that the white light, i.e., the low beam PL, 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, more preferably 1/60s or less. In addition, even when the period is greater than 1/30s, the afterimage effect is generated. For example, even if the period is 1/15s, the afterimage effect can be generated.
As described above, with the vehicle headlamp 1 of the present embodiment, since the incidence point SG of the green laser light having a longer optical path length to the phase modulation element assembly 54 than the red laser light and the blue laser light is smallest, even when the incidence point SG of the green laser light is greatly moved due to the vibration of the vehicle or the like, the incidence point SG can be suppressed from being exposed from the phase modulation element 54S as in the first embodiment. 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 incidence point of each laser beam is made different according to the optical path length to the irradiation position, the 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 incidence point, and an increase in the number of components can be suppressed. In addition, with the vehicle headlamp 1 of the present embodiment, since the laser light from the light sources 52R, 52G, 52B is incident on the common phase modulation element 54S, the number of phase modulation elements can be reduced and one 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 described. In addition, the same or equivalent components as those of the first embodiment are denoted by the same reference numerals except for the specific description, and overlapping description thereof is omitted.
Fig. 33 is a view showing a lamp unit 20 of a vehicle headlamp 1 according to a third embodiment of the present invention, similar 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, 54B are arranged separately from each other, and the like. The lamp unit 20 according to the third embodiment will be described below.
As shown in fig. 33, the optical system unit 50 of the lamp unit 20 of the present embodiment includes 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 as main configurations. 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.
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 light having a total number of beams larger than that of the red laser light to the rear. The third light source 52B emits blue laser light having a total number of beams larger than that of the green laser light to the rear. That is, in the present embodiment, the total number of red laser beams is minimum, and the total number of blue laser beams is maximum.
In addition, as in the first embodiment, the laser beams emitted from the light sources 52R, 52G, 52B are collimated by the collimator lenses 53R, 53G, 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 up-down direction. The red laser light collimated by the collimator lens 53R is incident on the incidence surface of the first phase modulation element 54R at an incidence point SR having a predetermined size.
The second phase modulation element 54G is disposed behind the second collimator lens 53G, and is inclined by 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 green laser light collimated by the collimator lens 53G is incident on the incidence surface of the second phase modulation element 54G at an incidence point SG larger than the incidence point SR.
The third phase modulation element 54B is disposed behind the third collimator lens 53B, and is inclined by about 45 ° in the opposite direction to the first phase modulation element 54R with respect to the front-rear direction and the up-down direction. The blue laser light collimated by the collimator lens 53B is incident on the incidence surface of the third phase modulation element 54B at an incidence point SB larger than the incidence point SG.
As described above, in the present embodiment, the incidence point SR of the red laser light having the smallest total number of light beams is smallest, and the incidence point SB of the blue laser light having the largest total number of light beams is largest.
Next, emission of light from the vehicle headlamp 1 will be described. Specifically, a case where a low beam is emitted from the vehicle headlamp 1 will be described.
The red laser light 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 entry point SR having a predetermined size. The red laser light is reflected by the first phase modulation element 54R while being diffracted, and the first light DLR, which is a light distribution pattern of the low beam, is emitted forward.
The green laser light emitted rearward from the second light source 52G is collimated by the collimator lens 53G, and is incident on the second phase modulation element 54G at an incident point SG larger than the incident point SR. The green laser light is reflected by the second phase modulation element 54G while being diffracted, and the second light DLG, which is a light distribution pattern of the low beam, is emitted upward.
The blue laser light emitted rearward from the third light source 52B is collimated by the collimator lens 53B, and is incident on the third phase modulation element 54B at an incident point SB larger than the incident point SG. The blue laser light is reflected by the third phase modulation element 54B while being diffracted, and the third light DLB, which is a light distribution pattern of the low beam, is emitted upward.
First light DLR emitted from first phase modulation element 54R is transmitted through first optical element 55f of combining optical system 55 disposed in front of first phase modulation element 54R. Second light DLG emitted from second phase modulation element 54G is reflected by first optical element 55f arranged above second phase modulation element 54G, and is emitted forward from first optical element 55f. Thus, the first combined light LS1 composed of the lights DLR, DLG propagates forward.
The first combined light LS1 emitted from the first optical element 55f is transmitted through the second optical element 55s of the combining optical system 55 disposed in front of the first optical element 55 f. Third light DLB emitted from third phase modulation element 54B is reflected by second optical element 55s disposed above third phase modulation element 54B, and is emitted forward from second optical element 55s. Thus, the second combined light LS2 composed of the light DLR, DLG, DLB is emitted forward from the second optical element 55s.
The light DLR, DLG, DLB forming the second combined light has the light distribution pattern of the low beam as described above. Accordingly, the second synthetic light LS2 emitted from the opening 40H propagates forward at a predetermined distance, and thus the light DLR, DLG, DLB can be superimposed on each other to form the white light, i.e., the low beam PL shown in fig. 30.
As described above, with the vehicle headlamp 1 of the present embodiment, the incidence point SB of the blue laser light having the largest total number of beams is largest, and the incidence point SR of the red laser light having the smallest total number of beams is smallest. Therefore, the energy per unit area of the red laser light incident on the phase modulation element 54R, the energy per unit area of the green laser light incident on the phase modulation element 54G, and the energy per unit area of the blue laser light incident on the phase modulation element 54B can be equally approximated. Therefore, deterioration of a specific phase modulation element can be suppressed faster than other phase modulation elements, and deterioration of the light distribution pattern over a long period of time can be suppressed. Therefore, the reduction in the lifetime of the vehicle headlamp can be suppressed.
In this way, by making the size of the incidence point of each laser beam different according to the total number of beams, the energy per unit area of each laser beam can be equalized without providing an optical system for adjusting the size of the incidence point, and an increase in the number of components can be suppressed.
(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. In addition, the same or equivalent components as those of the first embodiment are denoted by the same reference numerals except for the specific description, and overlapping description thereof is omitted.
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 of the first embodiment in that each of the light sources 52R, 52G, 52B has one, in that the lamp unit has three first light sources 52R, two second light sources 52G, and one third light source 52B.
The light sources 52R, 52G, 52B of the present embodiment can be identified as fig. 27 when vertically sectioned, but the first light sources 52R are arranged three along the depth direction perpendicular to the front-rear direction and the up-down direction, two second light sources 52G are arranged above the three first light sources 52R along the depth direction, and one third light source 52B is arranged above the two second light sources 52G. In the present embodiment, the total light flux amounts of the lights emitted from the plurality of light sources are substantially the same.
In order to improve the brightness and white balance of white light, for example, it is preferable to maximize the total light flux of red light, and minimize the total light flux of blue light out of red light, green light, and blue light. Therefore, in the lamp unit 20 of the present embodiment, as described above, the three first light sources 52R emitting red light are arranged to maximize the total light flux of red light, the two second light sources 52G emitting green light are arranged to minimize the total light flux of green light than the total light flux of red light, and the one third light source 52B emitting blue light is arranged to minimize the total light flux of blue light.
Fig. 34 is a front view showing the phase modulation element of the present embodiment together with the incidence point of light incident on the phase modulation element at the same angle 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 points SR of the red light emitted from these first light sources 52R are each smaller than the incidence points SG of the two green lights and the incidence point SB of the one blue light. The incident points SG of the green light emitted from the two second light sources 52G are smaller than the incident points SR, respectively. The number of third light sources 52B is one, and the number of third light sources 52B is the smallest, and the incidence point SB of blue light emitted from the third light sources 52B is the largest. As described above, in the present embodiment, the smaller the incidence point is, the more light sources are emitted.
Therefore, even if the first phase modulation element 54R is not made larger than the other phase modulation elements 54G and 54B, red light emitted from the plurality of light sources 52R can be received without leakage.
As described above, the smaller the incidence point is, the more light sources are emitted, and thus, without providing an optical system or the like for adjusting the size of the incidence point, the light emitted from the plurality of light sources by the phase modulation element can be received without leakage while suppressing an increase in the size of the phase modulation element, and an increase in the number of components can be suppressed.
In the present embodiment, the example was described in which the number (three) of the first light sources 52R is largest and the number (one) of the third light sources 52B is smallest, but it is sufficient that the smaller the incidence point, the more light sources are emitted from among at least two lights having different incidence points.
The present invention has been described above by taking the first to fourth embodiments as examples, and the present invention is not limited to these.
For example, in the first and second embodiments, the laser light having a longer optical path length to the phase modulation element is described as an example, but the laser light having a smaller incidence point to the phase modulation element is not limited to this. For example, as in the third embodiment, the laser light having a larger total number of beams may have a larger incidence point of the phase modulation element. In this case, as in the third embodiment, the energy per unit area of the red laser light incident on the phase modulation element 54R, the energy per unit area of the green laser light incident on the phase modulation element 54G, and the energy per unit area of the blue laser light incident on the phase modulation element 54B can be approximately the same. Therefore, degradation of a specific phase modulation element earlier than other phase modulation elements and the like can be suppressed.
In the third embodiment, an example was described in which the laser light having a larger total number of beams has a larger incidence point of the phase modulation element, but the present invention is not limited to this. For example, as in the first and second embodiments, the longer the optical path length to the phase modulation element, the smaller the incidence point of the phase modulation element may be. In this case, in the vehicle headlamp 1 of the third embodiment, a desired light distribution pattern can be easily obtained.
In the first to fourth embodiments, the example was described in which the incidence point SR of the red light emitted from the first light source 52R, the incidence point SG of the green light emitted from the second light source 52G, and the incidence point SB of the blue light emitted from the third light source 52B are all different, and at least two of the incidence points SR, SG, SB may be different in size. When the sizes of the incident points SR, SG, SB are different, the size of the point diameter can be more effectively adjusted, and an increase in the number of components can be more effectively suppressed.
Further, considering the case where the sizes of the incident points SR, SG, SB are different, for example, the longer the wavelength of light, the more the light tends to be refracted, or the smaller the incident point of the longer the wavelength of light may be. For example, as shown in fig. 35, the incident point SR of the longest wavelength red light, the incident point SG of the shorter wavelength green light than the red light, and the incident point SB of the shortest wavelength blue light are arranged in this order so as to increase the dot size, and the incident points SR, SG, SB are concentric circles. The red light, the green light, and the blue light are refracted by the phase modulation element 54S, reflected by the phase modulation element 54S, and emitted from the phase modulation element 54S. As described above, the longer the wavelength, the greater the refraction tends to be, and the red light emitted from the phase modulation element 54S is refracted at the maximum in the phase modulation element 54S, and the blue light emitted from the phase modulation element 54S is refracted at the minimum in the phase modulation element 54S. Here, as described above, the incident point SR is the smallest among the incident points SR, SG, SB which are concentric circles, and the incident point SB is the largest, so that the red light, green light, and blue light emitted from the phase modulation element 54S travel a predetermined distance, and the respective outer edges of the red light, green light, and blue light are superimposed, and bleeding of the color of the outer edge of the synthesized light composed of the red light, green light, and blue light is suppressed.
In the first to fourth embodiments, an example in which a reflective LCOS is used as a phase modulation element has been described, and other types of phase modulation elements may be used as the phase modulation element. For example, a transmissive LCOS, a diffraction grating, or GLV (Grating Light Valve) may be used. Further, GLV is a reflective phase modulation element in which a plurality of reflectors are provided on a silicon substrate, and can form different diffraction patterns by electrically controlling the deflection of the plurality of reflectors. In addition, when the phase modulation element is made to be LCOS, the voltage applied to the phase modulation element can be adjusted to appropriately change the phase modulation pattern. In addition, by using the phase modulation element as an LCOS, as in the second embodiment, different light can be incident on the common phase modulation element, thereby forming a predetermined light distribution pattern.
In the first to fourth embodiments, the vehicle headlamp 1 as the vehicle lamp irradiates the low beam PL, and the present invention is not particularly limited. 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, identification light OHS. In this case, the light emitted from each of the phase modulation elements 54R, 54G, and 54B preferably includes the identification light OHS. In such an embodiment, it can be understood that the light distribution pattern for night illumination is formed by the low beam PL and the sign recognition light OHS. Further, the term "night" as used herein is not limited to "night", but includes a dark place such as a tunnel. 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 having a strong light intensity, and the region PHA2 is a region having a lower light intensity than the region PHA 1. In addition, in still other embodiments, the vehicle lamp of the present invention may be applied to a structure that forms an image. In this case, the direction of the light emitted from the vehicle lamp and the mounting position of the vehicle lamp are not particularly limited.
Industrial applicability
The vehicle lamp according to the present invention can be used in the field of automobiles and the like, by providing a vehicle lamp in which an increase in the number of components is suppressed.

Claims (7)

1. A vehicle lamp is characterized by comprising:
a plurality of light sources emitting 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 light sources;
The magnitudes of the incident points of the phase modulating elements of at least two of the lights having different wavelengths are different from each other,
At least two of the lights are incident on the common phase modulation element through a combining optical system and combined.
2. A vehicle lamp according to claim 1, wherein,
The incident points of the plurality of lights are all different in size.
3. A vehicle lamp according to claim 1 or 2, wherein,
The phase modulation element is an LCOS.
4. A vehicle lamp according to claim 1 or 2, wherein,
The larger the total number of light beams, the larger the incidence point, among at least two of the lights having different sizes of the incidence points.
5. A vehicle lamp according to claim 1 or 2, wherein,
Of the at least two lights having different magnitudes of the incident points, the longer the light path length to the phase modulation element is, the smaller the incident point is.
6. A vehicle lamp according to claim 1 or 2, wherein,
Among at least two lights having different sizes of the incident points, the smaller the incident point is, the more the lights are emitted from the light source.
7. A vehicle lamp according to claim 2, wherein,
The longer the wavelength the smaller the point of incidence of the light.
CN202110959769.6A 2018-09-26 2019-09-23 Lamp for vehicle Active CN113606551B (en)

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