JPH0664476A - Lighting fixture for vehicle - Google Patents

Abstract

PURPOSE:To satisfy the light distribution conditions of a vehicle by a hologram prepared, by using a simple exposure system. CONSTITUTION:A lighting fixture for vehicle is provided with a hologram 31 for outgoing diffracted light by diffracting incident light from a light source 41, and the light source 41 for widening radiation light in the vertical direction to the flat surface formed by the optical axis of the incident light of the hologram 31 and the optical axis of the diffracted light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle lamp using a hologram.

[0002]

2. Description of the Related Art There is known a so-called high mount stop lamp in which a stop lamp is mounted at a high position at a rear portion of a vehicle in order to improve visibility of an occupant of a following vehicle. However, in passenger cars and many other vehicles, in order to increase the mounting position of the stop lamp, mount them on the rear parcel inside the rear window, or
Or, it has to be suspended from the roof of the rear part, and in any case, there is a problem that the rear view of the occupant is obstructed and the design of the rear part of the vehicle is restricted due to the installation of the high mount stop lamp.

In order to solve this problem, a vehicle lamp using a hologram for diffracting and diffusing incident light has been proposed (see, for example, Japanese Patent Laid-Open No. 2-241849). In this type of vehicle lamp, a hologram is attached to the rear window glass surface of the vehicle, and an illumination lamp that illuminates the hologram is provided at a position that does not hinder the occupant's rear view. Then, when the illumination lamp is turned on when the occupant operates the brake, the light emitted from the illumination lamp is diffracted / diffused by the hologram and guided to the eyes of the occupant of the following vehicle. In other words, the occupant of the following vehicle looks as if the stop lamp is provided on the rear window glass surface and the light is emitted from the stop lamp.

FIG. 13 shows an example in which a vehicle lamp using a conventional hologram is installed at the rear part of the vehicle. A hologram 3 is attached to the center of a rear window glass 2 of a vehicle 1, and an illumination lamp 5 for illuminating the hologram 3 is provided on a rear parcel 4 directly below the hologram 3. Here, if there is no illumination by the illumination lamp 5, the hologram 3
Is transparent and does not interfere with the occupant's rear view. Further, since the illumination lamp 5 is also embedded in the rear parcel 4, it does not hinder the occupant's rear view.

In the hologram 3, as shown in FIG.
For example, an interference fringe for diffracting and diffusing the incident light is exposed by using the coherent He-Ne laser light source 6 and the optical component group 7. The optical component group 7 includes an objective lens and a pinhole lens, and produces parallel light or diffused light.
Laser light emitted from the He-Ne laser light source 6 is split by a half mirror HM, one of which is guided to a hologram 3 coated with a photosensitive material through a mirror M and an exposure system 7a, and the other is reflected by a mirror M and It is guided to the hologram 3 via the exposure system 7b. These two laser beams interfere with each other on the hologram 3 to generate an interference fringe, and the interference fringe is exposed on the hologram 3. Next, the exposed hologram 3 is developed, and the above-described hologram 3 in which the bright and dark patterns of interference fringes are recorded is created.

As shown in FIG. 15, the hologram 3 is formed as an assembly of small holograms, and at the time of exposure, each small hologram is divided and exposed. The interference fringes recorded on each small hologram act as a diffraction grating, diffract the incident illumination light (incident light) 11, and emit the diffracted light 12. The hologram has a lens effect such that the diffracted light 12 is diffused in a wide range. The geometrical divergence angle of the laser light at the time of exposure is 35 ° because the relation between the diameter (φ) of the general lens and the focal length (f) is f ≧ 1.5φ.
It is a degree. The diffracted light due to this lens effect 12
The divergence angle of is substantially equal to the divergence angle of the laser beam during hologram exposure. Therefore, hologram 3
The divergence angle of the diffracted light 12 is practically 30 degrees at the maximum.

The illumination lamp 5 for illuminating the hologram 3 is
As shown in FIG. 16, it comprises a bulb 5a, a reflector 5b, a collimator lens 5c and a red filter 5d. The cross section of the reflector 5b has the same shape as a part of the ellipse, and the bulb 5a is arranged at the first focal point 5f as shown in FIG. The illumination light emitted from the bulb 5a is reflected by the reflector 5b, focused on the second focal point 5e, and then enters the collimator lens 5c. As is well known, the collimator lens 5c is a lens that emits light incident at various incident angles as parallel light, and the illumination light that has passed through the collimator lens 5c is incident on the red filter 5d as parallel light. The red filter 5d is, for example, a high-pass filter having a cutoff wavelength of 600 nanometers (nm), and the illumination light transmitted through the red filter 5d is viewed as red.

The illumination lamp 5 is turned on by a lighting circuit (not shown) in conjunction with a brake operation by an occupant, and emits red illumination light 11 to illuminate the hologram 3 as shown in FIG. The illuminated hologram 3 diffracts the illumination light 11 and distributes the diffracted light 12 behind the vehicle 1. The occupant of the following vehicle looks at the red diffracted light 12 emitted from the hologram 3 and visually recognizes the stop lamp provided on the rear window glass 2 of the vehicle 1 as if it were lit in red.

[0009]

By the way, the distribution angle of radiated light required for a high mount stop lamp of a vehicle is 15 degrees in the vertical direction and 90 degrees in the vehicle width direction.
However, the spread angle of the diffracted light emitted from the hologram,
That is, the light distribution angle is about 30 degrees at maximum as described above, and the light distribution angle in the vehicle width direction is insufficient. In order to widen the light distribution angle of the vehicular lamp using the hologram, the outgoing angle of the diffracted light is set for each small hologram so that the diffracted light spreads in the vertical direction and the vehicle width direction, especially in the vehicle width direction. Need to change. Therefore, it is necessary to change the incident angles of the two laser beams by the exposure systems 7a and 7b described above for each small hologram, and there is a problem that the exposure system becomes very complicated.

The problem of this exposure system will be described with reference to FIGS. In FIG. 18, a photosensitive material 13 is applied to the back surface of the hologram 3, and each small hologram is exposed using a slit plate 14 having a predetermined opening. As described above, the one laser light 15 emitted from the He-Ne laser light source 6 and divided into two by the half mirror HM is collimated by the objective lens 16, the pinhole 17 and the collimator lens 18 into the small hologram 3a as parallel light 15a. Is irradiated. The other laser light 19 of the laser light divided into two by the half mirror HM is applied to the small hologram 3a as the point light source light 19a diverged by the objective lens 20 and the pinhole 21. The photosensitive material 13 on the small hologram 3a has a parallel light 15a and a point light source 1
It is exposed by 9a, and interference fringes are recorded on the small hologram 3a.

Next, the small holograms 3b and 3c are sequentially exposed. When the small hologram 3a is exposed in order to widen the light distribution angle of the diffracted light 12 of the hologram 3 in the vertical direction and the vehicle width direction. It is necessary to adjust the exposure system to an angle different from the incident angle of the laser light of to expose. First, in order to widen the light distribution angle of the diffracted light 12 of the hologram 3 in the vehicle width direction, as shown in FIG. 18, the incident angle of the laser light 19 in the vehicle width direction is changed, or the hologram 3 itself is tilted. And rotate to change the incident angle in the vehicle width direction. Next, FIG. 19 as seen from the direction A in FIG.
As shown in, the incident angle in the vertical direction is changed in order to widen the light distribution angle in the vertical direction of the diffracted light 12 of the hologram 3. That is, it is necessary to change the incident angle of the laser beam three-dimensionally with each exposure of each small hologram. In particular, in order to obtain the required 90-degree light distribution angle with respect to the vehicle width direction, it is necessary to greatly change the incident angle, and there are many combinations of the incident angles of laser light in the vertical direction and the vehicle width direction. A complicated exposure system is required.

An object of the present invention is to provide a vehicular lamp which satisfies the light distribution conditions of a vehicle by means of a hologram created by using a simple exposure system.

[0013]

The present invention will be described with reference to FIG. 1 showing an embodiment.
It is applied to a vehicular lamp including a hologram 31 that diffracts incident light from a light source 41 and emits diffracted light.
Achieves the above object by allowing the emitted light to spread in a direction perpendicular to the plane formed by the optical axis of the incident light of the hologram 31 and the optical axis of the diffracted light.

[0014]

The light emitted from the light source 41 enters the hologram 31. The light emitted from the light source 41 has a spread in the direction perpendicular to the plane formed by the optical axis of the incident light of the hologram 31 and the optical axis of the diffracted light, and as a result, the diffracted light emitted from the hologram 31 also has a certain degree. It will have a large spread in the direction. By arranging the light source 41 and the hologram 31 so that this specific direction coincides with the vehicle width direction of the vehicle, the light distribution characteristics as a stop lamp of the vehicle can be satisfied.

[0015]

【Example】

-First Embodiment- Fig. 1 shows a rear portion of a vehicle equipped with a vehicular lamp of the first embodiment. A hologram 31 is attached to the center of the rear window glass 2 of the vehicle 1, and an illumination lamp 41 for illuminating the hologram 31 is provided on the rear parcel 4 directly below the hologram 31. The hologram 31 is composed of small holograms divided vertically and horizontally as shown in FIG. 2, and is exposed using the exposure system shown in FIG.

FIG. 3 shows an exposure system for the hologram 31. The exposure system uses the He-Ne laser light source 6 described above. In each of the small holograms forming the hologram 31, the parallel light 35 guided by the objective lens 32, the pinhole 33 and the collimator lens 34, and the objective lens 3
6 and the point source light 38 guided by the pinhole 37 is irradiated through the slit plate 40, and the photosensitive material 39 provided on the back surface of the hologram 31 is exposed with interference fringes of two laser beams. In this exposure system, the angle of incidence of the laser beam in the vertical direction and the vehicle width direction is changed for each small hologram, and the exposure is performed so that the diffracted light is diffused 15 ° in the vertical direction and 30 ° in the vehicle width direction.

FIG. 4 is a cross-sectional view of the illumination lamp embedded in the rear parcel 4 just below the hologram 31. As shown in FIG.
When the X axis is the vehicle width direction of the vehicle 1, the Y axis is the front-back direction of the vehicle 1, and the Z axis is the vertical direction as shown in Fig. 5, (a) shows the YZ section and (b) shows the XZ section. Indicates. Lighting lamp 41
Is composed of a bulb 41a, a reflector 41b, a cylindrical lens 41c, and a red filter 41d. The light emitted from the bulb 41a is reflected by the reflector 41.
After being focused on its focal point 41e by b, it is guided to the cylindrical lens 41c. Cylindrical lens 41
c is a uniaxial lens having the property of changing the angle of light as a lens with respect to one axis of the two axes perpendicular to the lens surface and orthogonal to the lens surface and not changing the light with respect to the other axis. Is. That is, the light transmitted through the cylindrical lens 41c is Y
On the −Z plane, it becomes parallel light as shown in FIG. 4A, while on the XZ plane, it becomes diffused light as shown in FIG. 4B. Here, the XZ plane is aligned with the vehicle width direction, and the YZ plane that becomes parallel light is aligned with the vehicle front-rear direction and mounted on the vehicle.

FIG. 5 shows a hologram 31 and an illumination lamp 41.
It is a XZ top view showing an example of arrangement with. When the hologram 31 and the illumination lamp 41 are provided at such positions,
The light distribution angle of the diffracted light in the vehicle width direction by the illumination lamp 41 is about 60 degrees, and together with the light distribution angle of 30 degrees in the vehicle width direction by the hologram 31 itself, the light distribution angle in the vehicle width direction is 90 degrees. Also, the light distribution angle of the hologram 31 in the vertical direction is 1
It is 5 degrees, and these light distribution angles in the vertical direction and the vehicle width direction satisfy the conditions for a high mount stop lamp.

-Second Embodiment- Next, a second embodiment using another illumination lamp will be described. FIG. 6 is an XZ sectional view of an illumination lamp 51 having a reflector composed of three types of parabolic mirrors. In this second embodiment, the hologram 31 similar to that of the first embodiment shown in FIG. 2 is used, and the hologram 31 and the illumination lamp 5 are used.
1 is a rear window glass 2 as shown in FIG.
And the rear parcel 4. The illumination lamp 51 includes a bulb 51a, a reflector 51b, and a red filter 51d. Reflector 51b
Is composed of three types of parabolic mirrors 52 to 54 as shown in FIG. When the focal point at which the bulb 51a is provided is set to the origin, the reference parabolic mirror 52 is expressed by the following equation. y = x ² / 4a (1) Further, the parabolic mirrors 53 and 54 are expressed by the following equation. y = x ² / 4b (2) It should be noted that the parabolic mirror 53 is tilted by 30 degrees clockwise with respect to the parabolic mirror 52, and the rod parabolic mirror 54 is relative to the parabolic mirror 52. Tilted counterclockwise by 30 degrees. Generally, a parabolic mirror has a property that when light is emitted from its focal point, the light reflected on the mirror surface becomes parallel light. Lighting lamp 51
The light emitted from the bulb 51a of the parabolic mirror 52-
Reflected at 54, the front of the illumination lamp 51 and 30 from the front
It is radiated in the direction inclined.

FIG. 8 shows a hologram 31 and an illumination lamp 51.
It is an XZ sectional view showing an example of arrangement. When the hologram 31 and the illumination lamp 51 are provided at such positions,
The distribution angle of the diffracted light in the vehicle width direction by the illumination lamp 51 is 6
The light distribution angle in the vehicle width direction becomes 90 degrees when combined with the light distribution angle in the vehicle width direction of 30 degrees by the hologram 31 itself. Further, the light distribution angle of the hologram 31 in the vertical direction is 15
The light distribution angle in the vertical direction and the vehicle width direction satisfies the conditions for a high mount stop lamp.

-Third Embodiment- Next, a third embodiment using another illumination lamp will be described. FIG. 9 is an XZ sectional view of an illumination lamp 61 in which a plurality of lamps are combined. In the third embodiment, as shown in FIG.
A hologram 31 similar to that of the first embodiment shown in FIG. 1 is used, and the hologram 31 and the illumination lamp 51 are respectively a rear window glass 2 and a rear parcel 4 as shown in FIG.
Shall be provided in. The illumination lamp 61 is composed of three lamps 62 to 64 and a red filter 61d, and each of the lamps 62 to 64 has bulbs 62a to 64a, elliptical reflectors 62b to 64b and collimating lenses 62c to 64c. The lamp 62 is the hologram 31
So that the diffracted light transmitted through is emitted to the rear of the vehicle 1,
The lamps 63 and 64 are mounted without tilting to the left and right, so that the diffracted light is emitted in the vehicle width direction behind the vehicle 1.
It is attached to the left and right with an inclination of 30 degrees.

FIG. 10 shows the hologram 31 and the illumination lamp 6.
2 is an XZ plan view showing an example of arrangement with No. 1; FIG. When the hologram 31 and the illumination lamp 61 are provided at such a position, the light distribution angle of the diffracted light in the vehicle width direction by the illumination lamp 61 becomes 60 degrees, and the light distribution angle of the hologram 31 itself in the vehicle width direction becomes 30 degrees. Together, the light distribution angle in the vehicle width direction is 90 degrees. Further, the light distribution angle of the hologram 31 in the vertical direction is 15 degrees, and these light distribution angles in the vertical direction and the vehicle width direction satisfy the conditions as a high mount stop lamp. If the hologram 31 is sufficiently illuminated by the central lamp 62, the light amounts of the left and right lamps 63 and 64 may be reduced accordingly.

-Fourth Embodiment-Next, a fourth embodiment using the hologram 71 divided in the vertical direction is used.
An example will be described. The hologram 71 is divided in the vertical direction as shown in FIG. 11, and each small hologram has the same lens effect as the cylindrical lens described above. That is, as shown in FIG. 11, each small hologram is exposed so that the diffracted light is diffused only in the vertical direction.

FIG. 12 shows an exposure system for the hologram 71.
This exposure system is based on the He-Ne laser light source 6 described above.
To use. In each of the small holograms forming the hologram 71, the parallel light 75 guided by the objective lens 72, the pinhole 73 and the collimator lens 74, and the objective lens 7
6, the point hole light 80 guided by the pinhole 77, the collimator lens 78, and the cylindrical lens 79 is irradiated using the slit plate 81, and the photosensitive material 82 provided on the back surface of the hologram 71 is interfered with by two laser beams. Expose stripes. The point source light 80 does not diffuse in the axial direction perpendicular to the paper surface due to the property of the cylindrical lens 79, but diffuses only in the axial direction parallel to the paper surface and perpendicular to the light traveling direction. In this exposure system, the incident angle of the laser beam in the vertical direction is changed for each small hologram, and the exposure is performed so that the diffracted light is diffused by 15 degrees in the vertical direction.

When such a hologram 71 is illuminated by the above-mentioned illumination lamps 41, 51, 61, respectively, the spread of the diffracted light in the vehicle width direction by the hologram 71 itself is small, so that the illumination lamps 41, 51, 61 are almost the same. Only 60 degree light distribution in the vehicle width direction due to
The light distribution angle in the vehicle width direction is lower than that in the above embodiment. However, such exposure of the hologram 71 may be performed by two-dimensionally changing the incident angle of the laser light with respect to each small hologram so that the diffracted light spreads only in the vertical direction.
It is simpler than the exposure system of the first to third embodiments described above. The shortage of the light distribution angle of the vehicle lamp using the hologram 71 with respect to the vehicle width direction increases the spread of the radiated light of the illumination lamp in the vehicle width direction, or the hologram 71 and its illumination. Two pairs of lamps may be provided on the left and right sides of the rear window 2 to secure the light distribution angle in the vehicle width direction.

As described above, the illumination lamp is constructed so that the light emitted from the illumination lamp to the hologram has a spread in the direction perpendicular to the plane formed by the optical axis of the incident light of the hologram and the optical axis of the diffracted light. However, since the illumination lamp and the hologram were arranged in the vehicle so that the direction of spread of the diffracted light of the hologram coincided with the vehicle width direction of the vehicle, the hologram created by a simple exposure system was used as a stop lamp for the vehicle. The light distribution condition can be satisfied.

The method of dividing the hologram and the number of divisions are not limited to those in the above embodiment. In addition, the hologram is exposed by Ar ⁺ laser (wavelength example 488 nm, 514.5
nm) and the like can also be used.

In the structure of the above embodiment, the illumination lamps 41, 51 and 61 form a light source, and the holograms 31 and 71 form a hologram.

[0029]

As described above, according to the present invention, the light source is constructed so that the emitted light has a spread in the direction perpendicular to the plane formed by the optical axis of the incident light of the hologram and the optical axis of the diffracted light. Therefore, the light distribution condition of the vehicle can be satisfied by the hologram created by using the simple exposure system.

[Brief description of drawings]

FIG. 1 is a diagram showing a rear portion of a vehicle equipped with a vehicle lighting device of a first embodiment.

FIG. 2 is a diagram showing a hologram according to the first embodiment.

FIG. 3 is a diagram showing a hologram exposure system of the first embodiment.

FIG. 4 is a sectional view of the illumination lamp according to the first embodiment.

FIG. 5 is a diagram showing an arrangement example of a hologram and an illumination lamp of the first embodiment.

FIG. 6 is a sectional view of an illumination lamp according to a second embodiment.

FIG. 7 is a diagram illustrating a shape of an illumination lamp according to a second embodiment.

FIG. 8 is a diagram showing an arrangement example of a hologram and an illumination lamp of a second embodiment.

FIG. 9 is a sectional view of an illumination lamp according to a third embodiment.

FIG. 10 is a diagram showing an arrangement example of a hologram and an illumination lamp of a third embodiment.

FIG. 11 is a diagram showing a hologram according to a fourth embodiment.

FIG. 12 is a diagram showing an exposure system according to a fourth embodiment.

FIG. 13 is a diagram showing an example in which a vehicle lamp using a conventional hologram is installed in a rear portion of a vehicle.

FIG. 14 is a diagram showing a laser light source and an exposure system for forming a hologram.

FIG. 15 is a diagram showing a hologram.

FIG. 16 is a sectional view of an illumination lamp.

FIG. 17 is a diagram illustrating the shape of a reflector.

FIG. 18 is a diagram showing an exposure system.

FIG. 19 is a view seen from the direction A in FIG. 18.

[Explanation of symbols]

1 Vehicle 2 Rear window glass 2a Lower end 3,31,71 Hologram 4 Rear parcel 6 He-Ne laser light source 7 Optical component group 7a, 7b Optical system 40,81 Slit plate 32,36,72,76 Objective lens 33,37, 73,77 Pinhole 34,62c, 63c, 64c, 74,78 Collimating lens 35,75 Object light 38,80 Reference light 39,82 Photosensitive material 41,51,61 Illumination lamp 41a, 51a, 62a, 63a, 64a Bulb 41b, 51b, 62b, 63b, 64b Reflector 41c, 79 Cylindrical lens 41d, 51d, 61d Red filter 41e Focus 52-54 Parabolic mirror M mirror HM half mirror

Claims (1)

[Claims] 1. A vehicular lamp including a light source and a hologram that diffracts incident light from the light source and emits diffracted light, wherein the light source emits emitted light along an optical axis of the incident light and the diffracted light. A vehicular lamp having a spread in a direction perpendicular to a plane formed by an optical axis of light.