JPS6248322B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an inner lens for a vehicle lamp,
In particular, this invention relates to a new inner lens equipped with a direct-light Fresnel prism.

The inner lens of this type of vehicle light uses direct light from the light source without using a paraboloid of revolution reflector, which takes up space, as the space inside the vehicle body where the light is housed, especially in the trunk space, increases. A vehicle lamp has been proposed in which the light is directly controlled by a lens to emit light, thereby making the lamp smaller, thinner, and lighter.

That is, the conventional lamp shown in FIG. 1 includes a housing a and an outer lens b on the front surface thereof.
A light source bulb P is disposed within a lamp chamber g in which a light source and an inner lens c are disposed. A fisheye prism d is provided on the inner surface of the outer lens b, a refractive prism section e is provided concentrically in the center of the inner surface of the inner lens c, and a reflective prism f is provided on the periphery of the inner lens c to form a Fresnel cut. ing. However, as shown in FIGS. 2A to 2C, such a conventional vehicle lamp has a concentric refractive prism e provided near the center of the optical axis of the inner lens c. The prism can be set to satisfy the light distribution, so it looks bright from the outside. However, in this refractive prism e, the angle range in which the light beam from the light source P enters an equal area on the front surface of the lens, for example, an area corresponding to one element of the prism, is an angle θ ₁ near the center. It gradually becomes smaller and becomes an angle θ ₂ near the boundary with the reflective prism f. Naturally θ
Since ₁ > θ ₂ , the amount of light incident on the part far from the center is small, and the surrounding area becomes dark. Furthermore, as shown in Figure 2, the light incident on the hanging portion (rising portion) H of the refractive prism e becomes lost light (light emitted far from the optical axis). That is, although direct light from the light source P is incident on the hanging surface (rising portion) H of the refractive prism e, it is diffused as lost light.
In addition, the angle of the light toward the inclined surface A of the refractive prism e and the angle of the light toward the hanging surface H become larger as the prism e moves away from the optical axis Z.
Therefore, the solid angle δ of the loss light region is the solid angle δ ₁ <
The loss of light increases due to Sn, and the peripheral area becomes a dark area F.
Therefore, such a dark portion F appears particularly prominently in a lamp that is elongated from side to side. Furthermore, as shown in Figure C, the light ray _L1 incident on the refractive prism e is received by the inclined surface A of the prism element, is refracted, passes through the element as it is, and exits from the surface B, which is the outer surface of the lens, so it is attenuated. Although the loss is small, the incident light beam L ₂ to the reflective prism f is received by the C plane of the hanging surface of the prism element, refracted, and further reflected by the inclined surface D.
The light is reflected by the lens and exits from the outer surface of the lens.
The light rays that are emitted through the reflecting prism f are attenuated more than those passing through the refractive prism e, resulting in a larger loss. Therefore, the refractive prism e
The output luminous intensity suddenly decreases at the boundary E of the reflecting prism f, and as a result, when viewed from the outside, there is a sharp brightness difference between the area near this boundary and the center, and when viewed from the front, a ring-shaped dark area F is created. It is. The existence of such a dark area F means that when looking at the lens surface,
Not only is the lighting filling bad and unsightly, but it also makes it impossible for the lens to emit light uniformly, which may impair the light distribution function, and causes problems such as the inability to fully achieve the display function of signal lights and the like, making it impossible to ensure visibility.

In view of the above-mentioned circumstances, the present invention utilizes the luminous flux in the range of the refractive prism part as effectively as possible, eliminates the loss of light especially at the rising part (downward surface) of the refractive prism part, and improves the relationship between the refractive prism part and the reflective system. It is an object of the present invention to provide an inner lens for a vehicle lamp that eliminates the dark part that occurs at the boundary with the prism part, increases the tolerance of the amount of light, enables a uniform light emitting surface, and improves visibility.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The inner lens of a vehicle lamp according to the present invention will be described below with reference to the accompanying drawings.

The illustrated example in FIGS. 3 and 4 is a first embodiment of the present invention, in which 1 is a housing defined by an outer lens 2 and an inner lens 3 disposed on the front surface of the housing 1. A light source bulb 4 is held in a holder 42 via a socket 41 and arranged in the lamp chamber.

The outer lens 2 and the inner lens 3 are molded from a transparent synthetic resin such as acrylic resin. The outer lens 2 is arranged in front of the inner lens 3 as a cover lens. The inner lens disposed between the outer lens 2 and the light source bulb 4 has a refractive system prism part 31 formed in a lattice shape on the outer surface 30a of the central part near the optical axis Z. A lattice-shaped reflective prism section 32 is provided on the inner surface 30b of the periphery of the prism section 31. Furthermore, a fisheye prism section 33 and a fisheye prism section 34 are arranged in a lattice pattern on the inner and outer surfaces 30a and 30b of the lens corresponding to the lattice refraction prism section 31 and the lattice reflection prism section 32, respectively. It is provided.

More specifically, the inner lens 3 has a lattice-like refractive prism section 31 provided on the outer surface 30a of the central portion (near the light source) near the optical axis Z, and a rising portion (downward surface) H near the center of the optical axis. A refractive prism part, a so-called simple refractive prism part 31a, is formed substantially parallel to the optical axis. So-called total refraction prism section 31
b. Furthermore, the simple refraction system prism part 31a is provided at a distance of about 1L from the center of the optical axis Z, which is approximately equal to the distance L between the optical axis 4 and the surface of the inner lens 3, and the total refraction system prism part around it is provided. 31b is provided at a distance of about 1L to 2L from the center of the optical axis. These distances are arbitrarily set based on the optical design of the refractive prism section 31, but the formation range of the all refractive prism section 31b is such that the light beam from the light source 4 of the simple refractive prism section 31a is from the center. It is best to form it in a range where the luminous flux density gradually decreases as the distance increases. The lattice-shaped reflection system prism section 32 formed on the lens inner surface 30b at the periphery of the lattice-shaped refraction system prism section 31 reflects and controls the direct light from the light source 4 as a substantially parallel ray with respect to the optical axis. It is configured. Furthermore, the refraction system prism section 31 and the reflection system prism section 32
The grid-shaped fisheye prism parts 33 and 34 provided on the inner and outer surfaces 30a and 30b of the lens corresponding to the
Prism element 33 among each prism element
is a fisheye prism section that refracts the emitted light from the light source toward the refraction system prism section 31 and controls the light as diffused light, and the prism element 34 redirects the substantially parallel reflected light from the reflection system prism section 32 toward the outer lens. It is composed of a fisheye prism that refracts the light and controls the light as diffused light. In the illustrated example, the fisheye prism parts 33 and 34 arranged in a grid on the inner and outer surfaces 30a and 30b of the inner lens 3 are the grid-like refractive prism part 31, the grid-like reflective prism part 32, and the grid-like rectangles. The pitches of the lattice-shaped fisheye prism portions 33 and 34 are set to the same size in order to uniformly form the lighting filling in a lattice shape when viewed from the front of the lens. The pitch is the refraction system prism section 3.
In terms of the optical design of the reflective prism section 1 and the reflective prism section 32, it is possible to configure the prism element to be large and to have a small curvature to reduce the amount of diffused light, which can be arbitrarily set in the optical design. Note that the symbol x is a rectangular boundary line between the lattice-like refractive prism section 31 at the center of the lens outer surface 30a and the lattice-like reflective prism section 32 at the periphery of the lens inner surface 30b.

The inner lens 3 configured as described above is
The light effect during lighting will be explained using FIG. 4.
Among the emitted light (direct light) from the light source 4, the simple refraction system prism section 31a of the lattice-like refraction system prism section 31
The incident light beam _L1 enters the fisheye prism section 33, is refracted and transmitted as diffused light, is refracted again by the inclined surface of the prism element of the simple refraction system prism section 31a on the outer surface, and is all emitted from the outer lens. A large amount of light is emitted in two directions. Then, the incident light beam L ₂ to the total refraction system prism section 31b around it,
Similarly, L ₃ also enters the fisheye prism section 33, is refracted and transmitted as diffused light, and one of the rays L ₂ is refracted again at the inclined rising portion H of the prism element of the total refraction system prism section 31b, and the other ray
L ₃ is refracted again by the inclined surface of the prism element, and both rays L ₂ and L ₃ are all emitted, and a large amount of light is emitted in the direction of the outer lens 2. In addition, the incident light beam L ₄ to the grating reflective prism part 32 is received by the hanging surface of the prism element, refracted, further reflected in parallel by the inclined surface, transmitted, and refracted again by the fisheye prism part 34 on the outer surface. The light rays L ₁ , L ₂ , L ₃ , and L ₄ emitted in the direction of the outer lens 2 pass through the outer lens (cover lens) 2 and are emitted forward. It is something that will be done.

In the inner lens 3, a lattice-like refractive prism part 31 is provided on the outer surface 30a of the central part near the optical axis, and a lattice-like reflective prism part 32 is provided on the inner surface 30b of the peripheral part of the refractive prism part 31. , it is possible to solve the problem that the light loss region increases due to the rising part H on the inner surface of the refractive prism part and the dark part occurs in the peripheral part as in the conventional case. Lens inner and outer surfaces 30a, 3 corresponding to the grid-like reflective prism portion 32 are formed on the lens inner surface 30b around the system prism portion and the lens inner surface 30b.
0b and a fisheye prism section 33 that controls and emits diffused light toward the lattice-like refraction system prism section 31.
and a fisheye prism section 34 that refracts the substantially parallel reflected light from the lattice-like reflective prism section 32 forward and controls and emits it as diffused light. Since the refractive prism part 31a is composed of the refractive prism part 31a and the all-refractive prism part 31b in the area where the luminous flux density decreases around the refractive prism part 31a, the luminous flux in the region with high luminous flux density can be effectively used without loss, and the refractive prism part Part 3
Since the range of 1 can be used to the maximum,
This refractive prism section 31 refracts all incident light from the light source by the prism element and emits it forward, so it can emit a large amount of light in front of the lens. The ring-shaped dark part that occurs at the boundary with the prism part does not occur, and the lens surface is provided with a uniform light-emitting surface, so the lighting filling is also good. With each prism segment, sufficient light distribution characteristics can be obtained, especially when the lens surface is inclined with respect to the lamp axis, and it is possible to increase the margin of light amount and increase the light distribution value, improving visibility. It is something that can be achieved.

The illustrated examples in FIGS. 5A to 5C are other embodiments of the inner lens of the vehicle lamp according to the present invention.
The lattice refraction system prism part 31 provided at 0a is formed into a square when viewed from the front, and the inner surface 3 of the peripheral part
Boundary line x between 0b and the grid-like reflective prism section 32
is constructed in a square shape, and the lattice-like refraction system prism section 31 includes only a simple refraction system prism section 31a. This lattice-like refractive prism section 31 is advantageous for a lens in which the distance L between the light source 4 and the lens surface is set to about 1L from the center of the lens.

As is clear from the above embodiments, the inner lens of the vehicle lamp of the present invention is an inner lens disposed between the outer lens of the lamp and the light source, and the inner lens is located at the center near the optical axis. A lattice-shaped refractive prism section is provided on the outer surface of the lens, and a lattice-shaped reflective prism section is provided on the inner surface of the periphery of the refractive prism section, and the inside of the lens corresponds to the refractive prism section and the reflective prism section. Since it is characterized by having a fisheye prism section on the outer surface, there is no loss of light caused by the rising part H of the refraction system prism section as in the conventional case, and it is possible to eliminate the loss of light caused by the rising part H of the refraction system prism section. The light beam can be used effectively without loss, and the range of the refractive prism section can be maximized. All the incident light from the light source is emitted forward, so a large amount of light is emitted in front of the lens. In addition, a uniform light-emitting surface can be obtained without damaging the lighting filling due to the occurrence of a dark area at the boundary between the refractive prism part and the reflective prism part, as in the conventional case. The reflective prism section is composed of each prism segment in a grid pattern, so
In particular, when the lens surface is tilted with respect to the lamp axis, the light distribution will not be distorted, sufficient light distribution characteristics will be obtained, the margin of light amount will be increased, the light distribution value will be increased, and visibility will be improved. It has the following effects.

It should be noted that, as a matter of course, the present invention is not limited only to the examples.

[Brief explanation of the drawing]

Figures 1 and 2 show a conventional example, Figure 1A is a front view, Figure 1B is a sectional view taken along line A-A in Figure I,
2A to 2C are explanatory diagrams showing the optical action of a conventional inner lens, and FIGS. 3 and 4 show an example of implementation of the inner lens of a vehicle lamp according to the present invention.
Figure A is a front view of the lamp, and Figure B is B- in Figure A.
4 is an enlarged sectional view illustrating the optical action of the inner lens; FIG. 5 shows another embodiment of the present invention; figure A is a front view; C
A sectional view taken along the line DD in FIG. DESCRIPTION OF SYMBOLS 1... Housing, 2... Outer lens (cover lens), 3... Inner lens, 31... Grid-like refraction system prism part, 31a... Simple refraction system prism part, 31b... Total refraction system prism part, 32... Grid-like reflection system prism part parts, 33, 34... lattice fisheye prism part, 4... light source bulb.

Claims (1)

[Claims] 1. An inner lens disposed between an outer lens of a lamp and a light source, wherein the inner lens is provided with a lattice-shaped refractive prism part on the outer surface of the central part near the optical axis, and the periphery of the refractive prism part. An inner lens for a vehicle lamp, characterized in that a lattice-like reflective prism part is provided on the inner surface of the inner lens, and fisheye prism parts are provided on the inner and outer surfaces of the lens corresponding to the refractive prism part and the reflective prism part. .