JPH08106804A - Vehicle lighting - Google Patents

Abstract

(57) [Abstract] [Purpose] The non-parallel light emitted directly from the lamp without passing through the reflector can be converted into parallel light by the hologram to improve the light distribution, and the parallel light reflected by the reflector can be directly used. (EN) Provided is a vehicular lamp that can be transmitted to sufficiently increase the light distribution amount. [Structure] Parallel light and non-parallel light emitted from a lamp 5 and reflected by a reflector 6, and parallel light and non-parallel light directly emitted from a lamp 5 enter a hologram 8. At this time, the parallel light directly emitted from the lamp 5 and the reflector 6
The parallel light reflected from the hologram 8 passes through the hologram 8 as it is, and the non-parallel light directly emitted from the lamp 5 and the non-parallel light reflected from the reflector 6 are diffracted by the hologram 8.
It is emitted forward as parallel light and is emitted forward through the light distribution lens 7. This increases the amount of parallel light that enters the light distribution lens 7 in front of the hologram.
The amount of effective light distributed by the light distribution lens 7, that is, the amount of light distribution is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular lamp, and more particularly to a vehicular lamp such as a headlight which is illuminated in a specific direction.

[0002]

2. Description of the Related Art For example, as shown in FIG. 9, a conventional vehicle headlamp generally used has a reflector 31 on the back of a halogen lamp 30 and a light distribution lens 32 on the front thereof. The illumination light is emitted toward a specific front direction.

However, the light emitted from the lamp 30 and reflected in a substantially horizontal direction by the reflector 31 is properly distributed by the light distribution lens 32, but the lamp 30
The light radiated in a non-horizontal direction from the light or the light reflected in a non-horizontal direction by the reflector 31 is distributed to the light distribution lens 32.
There is a problem that the ratio of the light distribution amount to the total emitted light amount of the lamp is low because the light is not properly oriented and the light of the lamp is wasted.

Therefore, conventionally, a transmissive hologram is arranged between the halogen lamp and the light distribution lens, and non-parallel light (light that is non-parallel to the axis) emitted directly from the lamp without passing through a reflector is provided. A vehicle lamp in which parallel light is made by a hologram to improve the amount of light distribution is disclosed in Japanese Patent Laid-Open No.
It is proposed in Japanese Patent No. 16085.

[0005]

However, in the conventional vehicular lamp in which the hologram is arranged between the lamp and the light distribution lens, the non-parallel light emitted directly from the lamp without passing through the reflector (the axis of the lamp). The hologram is manufactured to diffract the incident light so that the non-parallel light beam that is inclined with respect to the parallel light is made into parallel light. Although it is diffracted into parallel light, the parallel light reflected by the reflector does not pass through the hologram as it is and is diffracted by the hologram, so the light quantity of the parallel light incident on the light distribution lens is reduced and There was a problem that it did not improve.

The present invention has been made in view of the above points, and the non-parallel light emitted directly from the lamp without passing through the reflector is converted into parallel light by the hologram, and the light distribution amount can be improved. An object of the present invention is to provide a vehicular lamp capable of transmitting parallel light reflected by a reflector as it is and sufficiently increasing the light distribution amount.

[0007]

In order to achieve the above object, the vehicular lamp according to the present invention reflects a lamp serving as a light source and the light emitted from the lamp forward as parallel light or non-parallel light. The reflector and the lamp and the lamp are arranged in front of the reflector, and the parallel light directly emitted from the lamp and the parallel light reflected from the reflector are transmitted as they are, and the non-parallel light directly emitted from the lamp and the light reflected from the reflector are transmitted. The hologram includes a hologram that diffracts the non-parallel light and emits it as parallel light forward, and a light distribution lens that is arranged in front of the hologram and that distributes the light incident from the hologram in a predetermined direction and emits it.

Here, the hologram can be manufactured by exposing parallel light to the hologram dry plate at an incident angle inclined by a predetermined angle when the hologram dry plate is exposed at the time of manufacturing.

[0009]

In the vehicular lamp having such a structure, when the lamp is turned on, the parallel light and the non-parallel light emitted from the lamp and reflected by the reflector, and the parallel light and the non-parallel light directly emitted from the lamp are Enter the hologram. At this time, the parallel light directly emitted from the lamp and the parallel light reflected from the reflector pass through the hologram as it is, and the non-parallel light directly emitted from the lamp and the non-parallel light reflected from the reflector are diffracted by the hologram. , Is emitted forward as parallel light and is emitted forward through a lens for light distribution.

Therefore, the amount of parallel light incident on the light distribution lens in front of the hologram is effectively increased as compared with the prior art.
As a result, the amount of effective light distributed by the light distribution lens, that is, the amount of light distribution can be significantly improved compared to the conventional case.

The above hologram is formed from two holograms, and the two holograms are arranged in front of the lamp in the left-right direction or in the up-down direction, and the outer edge portions of the left-right or upper-lower holograms are inclined so as to approach the reflector side. By arranging them in such a manner, the amount of light incident on the hologram can be increased.

That is, since the halogen lamp that is usually used for the lamp generally has a small amount of light emitted from the leading portion and a large amount of light emitted from the outer peripheral portion of the bulb due to its structure, two holograms are thus formed. By arranging the two in a tilted manner, it is possible to further increase the light distribution amount as compared with a case where one hologram is simply arranged vertically in front of the lamp.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view of a prismatic vehicle headlamp to which the present invention is applied, FIG. 2 is a schematic vertical sectional view thereof, and FIG. 3 is a schematic horizontal sectional view thereof. Reference numeral 5 denotes a lamp such as a halogen lamp which serves as a light source, and the lamp 5 is arranged in the center of the inside of a reflector 6 having a concave reflecting mirror.

A light distribution lens 7 is arranged in front of the lamp 5 and the reflector 6, and further the light distribution lens 7 is arranged.
The hologram 8 is arranged between the lamp and the lamp 7 (reflector 6). The reflector 6 is configured to reflect most of the light emitted from the lamp 5 to the reflector 6 side in parallel with an axis (central axis in the front-back direction of the headlight) S. The hologram 8 is arranged perpendicularly to its axis S. The hologram 8 reflects the parallel light emitted directly from the lamp 5 in parallel with the axis S and the parallel light reflected by the reflector 6 in the direction parallel to the axis S. Non-parallel light that is transmitted as it is and is non-parallel in the vertical plane perpendicular to the axis S emitted directly from the lamp 5, and non-parallel light reflected by the reflector 6 in the non-parallel direction in the vertical plane perpendicular to the axis S. It is configured to diffract light and emit it as parallel light.

In the hologram 8, as shown in FIG. 3, the non-parallel light L22 which is incident from a direction non-parallel to the horizontal plane parallel to the axis S with respect to the vertical line of the hologram surface is given a predetermined angle α ( For example, it is configured to be bent inward by 5 ° to 30 °) to diffract and emit.

The light distribution lens 7 is formed in a rectangular shape, and as shown in FIG. 2, the lower part thereof is projected forward and the upper part thereof is arranged so as to be inclined rearward. This light distribution lens 7 is
The parallel or non-parallel light emitted from the hologram 8 is distributed in a predetermined direction and is suitable for a headlamp, that is, a light distribution having a predetermined spread in the up and down direction and a left and right spread in the left and right direction. Is obtained.

FIG. 4 shows a schematic plan view of the optical system when the hologram 8 is exposed. The hologram 8 is exposed using such an optical system and is manufactured as a Fresnel hologram. Reference numeral 10 is a hologram dry plate, which is coated with, for example, dichromated gelatin or a photopolymer as a photosensitizer on a base material such as soda glass, and after drying, about 10 to 2
It is formed to have a thickness of 0 μm.

A laser oscillator 11 serves as a light source, and emits laser light having a wavelength of 515 nm, for example. The laser light emitted from the laser oscillator 11 passes through the mirror 12,
It reaches the half mirror or beam splitter 13, where it is split into two systems of light. Then, one of the light fluxes passes through the mirror 14, the objective lens 15 and the pinhole 16, becomes parallel light through the lens 17, and is incident on the hologram dry plate 10. The other light flux passes through the mirror 18 and
The optical system is configured so that it enters the hologram dry plate 10 as divergent light through the objective lens 19 and the pinhole 20.

In the past, when a hologram of this type was manufactured, parallel light was made to enter the hologram dry plate substantially perpendicularly to be exposed, but in the present invention, parallel light is not perpendicular to the surface of the hologram dry plate 10. Instead, as shown in FIG. 4, the angle of the lens 17 is set so that the light is incident at an angle β with respect to the vertical line of the surface. The incident angle β of the parallel light is in the horizontal plane of the optical system, and the parallel light in the vertical plane has an inclination angle of 0 with respect to the hologram dry plate 10.
It is incident at °, that is, vertically.

The incident angle β of the parallel light varies depending on the wavelength of the laser light used or the emission angle α of the non-parallel light diffracted / emitted during reproduction, but the wavelength of the laser light is 515 nm, for example. When the emission angle α of the non-parallel light L22 is 5 ° to 30 °, the incident angle β of the parallel light is 4 ° to
25 ° is suitable.

Further, the irradiation position of the divergent light, that is, the distance from the pinhole 20 for irradiating the divergent light to the hologram dry plate 10 is set to be 10% to 20% more than the distance between the lamp 5 and the hologram 8 in use. .

At the time of exposure using the above optical system,
As shown in FIG. 4, the laser light emitted from the laser oscillator 11 passes through the mirror 12 and enters the beam splitter 13, where it is split into two light fluxes.

One light beam is reflected by the mirror 14 and the objective lens 1.
5. After passing through the pinhole 16 and the lens 17, the light becomes parallel light there and is incident on the surface of the hologram dry plate 10 at an incident angle β. The other light flux passes through the mirror 18 and the objective lens 19, passes through the pinhole 20, becomes divergent light, and enters the surface of the hologram dry plate 10. On the hologram dry plate 10, two systems of light are incident as parallel light and divergent light to generate interference fringes, and the interference fringes are recorded on the hologram dry plate 10.

As shown in FIG. 4, the first exposure is performed on the left half of the hologram dry plate 10, then the hologram dry plate 10 is rotated 180 °, and the right half of the hologram dry plate is exposed. As described above, by performing the exposure twice, it is possible to manufacture a hologram having a large shape using the lens 17 having a relatively small diameter. Also,
The lens 19 and the pinhole 20 do not get in the way.

As described above, the exposed hologram dry plate 10 is then subjected to a predetermined developing / fixing process, dried at high temperature, and sealed to complete the transmission type Fresnel hologram 8. When the hologram 8 is mass-produced, the hologram produced as described above is used as a master hologram, and the master hologram is exposed by superimposing another dry plate thereon, and contact copy is performed.
A similar hologram 8 can be mass-produced.

Then, such a hologram 8 is shown in FIG.
As shown in FIG. 5, the headlamp is used by being disposed between the lamp 5 and the light distribution lens 7.

In such a hologram headlight, when the lamp 5 is turned on, parallel light emitted from the lamp 5 and reflected in a substantially horizontal direction by the reflector 6, light emitted from the lamp 5 in a non-horizontal direction, The light reflected in the non-horizontal direction by the reflector 6 first enters the hologram 8. The light incident on the hologram 8 is diffracted with the diffraction efficiency as shown in FIG.

At this time, the parallel light L1 incident on the hologram 8 in parallel is diffracted at a wavelength of about 400 nm or less as shown in FIG. 5, but at a wavelength of about 500 to 650 nm, that is, in the visible light region. Therefore, the hologram 8 is hardly diffracted in a region having high visibility, and the hologram 8 is satisfactorily transmitted as it is.

On the other hand, the non-parallel light L2 incident non-parallel to the hologram 8 is efficiently diffracted in the visible light region (the region where the human visual sensitivity is high) as shown in FIG. 5, and as shown in FIG. The parallel light L22 is emitted. Note that, as shown in FIG. 3, in the horizontal plane, the non-parallel light incident on the hologram 8 exits while being inclined inward at the angle α, and the non-parallel light that is easily dispersed in the left-right direction is collected near the center.

As described above, the parallel light L1 incident on the hologram 8 in parallel is satisfactorily transmitted as the parallel light L11, and the non-parallel light L2 is diffracted by the hologram 8 and the parallel light L2.
The light quantity of the parallel light beams L11 and L22 incident on the light distribution lens 7 in front of the hologram 8 is effectively increased, and the effective light distributed by the light distribution lens 7 is thereby increased. Light quantity, that is, light distribution quantity is about 10% compared to conventional
It can be improved by up to 40%.

The light diffracted by the hologram 8 is color-separated due to chromatic aberration, and various colored lights are easily generated. However, since these colored lights are mixed with the white light that has passed through the hologram, they are not noticeable. Absent.

6 to 8 show another embodiment. In this example, two holograms 18 and 28 are arranged so as to be inclined with respect to the axis S. That is, the two holograms 18 and 28 are arranged with a slight gap between them so that they are erected on the left and right sides of the axis S in a front view, and as shown in FIG. Is arranged so as to approach the rear reflector 6 side, and is inclined so that the edge portion on the center side is projected forward.

The holograms 18 and 28 are exposed at the time of manufacture using an optical system similar to the optical system of FIG. 4 described above, but at this time, the angle of the hologram dry plate 10 is at the time of reproduction (at the time of use). Depending on the tilt angle of the
Exposure is performed by inclining so as to approach.

In this way, the two holograms 18 and 28 are
Also in the headlamp that is arranged in front of the lamp 5 with a tilt, the parallel light incident parallel to the holograms 18 and 28 is satisfactorily transmitted as it is, and the non-parallel light is the hologram 18, Since the light is diffracted at 28 and emitted as parallel light, the amount of parallel light incident on the light distribution lens 7 in front of the hologram is effectively increased.

Further, the halogen lamp usually used for the lamp 5 generally has a small amount of light emitted from the leading portion and a large amount of light emitted from the outer peripheral portion of the bulb due to its structure.
For this reason, the two holograms 18 and 28 are arranged on both sides of the axis S with a slight gap therebetween, and the holograms 1 on the left and right sides in plan view are arranged.
Bring the outer edges of 8, 28 closer to the rear reflector 6 side,
If you arrange it so that the edge on the center side goes forward,
The amount of light incident on the holograms 18, 28 is much increased.
Therefore, the amount of light distribution can be increased as compared with the case where one plate-shaped hologram 8 is used.

Although not shown, two holograms 1
8 and 28 may be arranged with a slight gap between them so that they are erected on the upper and lower sides of the axis S (see FIG. 8) in a front view. Also in this case, the light distribution lens 7 is designed to have a predetermined spread in the up-down direction and slightly in the left-right direction.

[Brief description of drawings]

FIG. 1 is a schematic front view of a headlamp showing an embodiment of the present invention.

FIG. 2 is a schematic sectional view taken along the line II-II in FIG.

FIG. 3 is a schematic sectional view taken along the line III-III in FIG.

FIG. 4 is a plan view showing an optical system for exposure when the hologram 8 is manufactured.

FIG. 5 is a graph showing the diffraction efficiency of hologram 8.

FIG. 6 is a front view of a headlamp of another embodiment.

FIG. 7 is a schematic sectional view taken along line VII-VII in FIG.

8 is a schematic sectional view taken along the line VIII-VIII of FIG.

FIG. 9 is a schematic sectional view of a conventional headlamp.

[Explanation of symbols]

 5-lamp, 6-reflector, 7-lens for light distribution, 8-hologram, 10-hologram dry plate.

Front Page Continuation (72) Inventor Haruo Teraoka 5-3-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Tsutomu Yamamoto 2-9-9 Nakameguro, Meguro-ku, Tokyo Stanley Electric Co., Ltd.

Claims (3)

[Claims] 1. A lamp serving as a light source, a reflector for reflecting light emitted from the lamp as parallel light or non-parallel light, and a lamp disposed in front of the lamp and the reflector, and directly from the lamp. The parallel light emitted and the parallel light reflected from the reflector are transmitted as they are, and the non-parallel light directly emitted from the lamp and the non-parallel light reflected from the reflector are diffracted and emitted forward as parallel light. And a light distribution lens that is disposed in front of the hologram and that distributes and outputs light incident from the hologram in a predetermined direction. 2. The hologram, when exposing the hologram dry plate at the time of manufacturing, emits parallel light to the hologram dry plate.
The vehicular lamp according to claim 1, wherein the vehicular lamp is manufactured by exposing at an incident angle inclined by a predetermined angle. 3. The hologram, wherein two holograms are arranged side by side in front of the lamp in the left-right direction or in the up-down direction, and the outer edges of the holograms in the left-right direction or the up-down direction are tilted so as to approach the reflector side. The vehicular lamp according to claim 1 or 2, characterized in that