JPH103803A - Inner lens of lamp for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the utilizing efficiency of light by forming a reflector prism of a Fresnel lens with a tip side effective surface in a center side surface thereof and a thick formed surface in a base side thereof. SOLUTION: An inner lens 2 of a lamp for vehicle is formed by providing a tip side effective surface 212 on the center side surface of a reflective prism 21 of a Fresnel lens and a thickly formed surface 213 on the base side surface thereof. Since the base part of the prism 21 is formed thick, resin can be filled to the tip of the prism 21 neither prolonging the forming time nor applying a pressure. As a result, the tip of the prism 21 is formed in an acute angle, not formed into a round shape, and since the light, which enteres the tip of the prism 21, is made to exit as a parallel light, so that loss of the light is eliminated, and the utilization efficiency of the light is improved. Namely, performance of the luminous intensity distribution of a lamp for vehicle can be improved. In the prism 21 separated from a light source bulb 4, brightness of an end part thereof separated from the bulb 4 and a part thereof near the bulb 4 are evened, and a non-light emission part is reduced, and a light emitting part can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inner lens of a vehicular lamp having a Fresnel lens for emitting incident light from a light source bulb as parallel light, and more particularly to a vehicular lamp having improved light use efficiency. Of the inner lens.

[0002]

2. Description of the Related Art Referring to FIG.
This will be described with reference to FIG. In the figure, reference numeral 1 denotes a lamp housing. The lamp housing 1 has an opening 1 at the front.
Has zero. An inner lens 2 composed of, for example, an outer lens 3 of a fisheye lens (or a transparent lens) and a Fresnel lens is fixed to the opening 10 of the lamp housing 1. This outer lens 3
The lamp chamber 11 is defined by the inner lens 2 and the lamp housing 1. The light source bulb 4 is disposed in the lamp room 11.

The above-mentioned inner lens 2 is composed of a refraction prism (refraction prism) 20 disposed at a central portion facing the light source bulb 4 and a reflection prism (refraction prism) disposed around the refraction prism 20. (A total reflection prism) 21. The refractive prism 20 has a shape in which the surface on the center side is vertical and the surface on the opposite side is inclined, and is formed at the same pitch. On the other hand, the reflection type prism 21
Is a surface on the center side (a surface on the light incident side) 2 as shown in FIG.
10 and an opposite surface (a surface on the total reflection side) 211 form an isosceles triangular shape inclined at substantially the same angle, and are formed at the same pitch.

Next, the operation of the inner lens 2 will be described. First, light incident on the side of the refracting prism 20 of the inner lens 2 from the light source bulb 4 is refracted on the inclined surface of the refracting prism 20 and refracted by the inner lens 2.
Into the inner lens 2 substantially parallel to the optical axis Z-Z.
The light goes straight through the inside and is emitted from the surface of the inner lens 2 to the outer lens 3 side. On the other hand, light incident on the reflective prism 21 side of the inner lens 2 from the light source bulb 4 is reflected by the reflective prism 2 as shown by a solid line arrow in FIG.
1, the light enters the inner lens 2 from the inclined surface 210 on the center side thereof, travels straight through the inner lens 2, is totally reflected on the inclined surface 211 on the opposite side, and travels straight through the inner lens 2 almost parallel to the optical axis Z-Z. From the surface of the lens 2 to the outer lens 3
Emitted to the side.

As described above, the light coming from the inner lens 2 substantially parallel to the optical axis ZZ is transmitted to the outer lens 3.
And is emitted from the outer lens 3 to the outside as diffused light. Alternatively, when the outer lens 3 is transparent, the light is emitted as parallel light from the outer lens.

[0006]

However, in the above-described inner lens 2 of the conventional vehicle lighting device, particularly, the reflecting prism 21 has a height and its tip forms an acute angle as shown by a broken line in FIG. . For this purpose, the inner lens 2
When resin is molded with a resin, the resin
Does not spread to the tip of the reflection prism 21
Is rounded as shown by the solid line in FIG. As a result, when light is incident on the rounded portion at the tip in the reflection system prism 21, as shown by the dotted arrow in FIG. Thus, the loss of light from the light source bulb 4 is large, and the light use efficiency is poor.

On the other hand, in the reflective prism 21 far from the light source bulb 4, as shown by a dashed line arrow in FIG. 4, a certain prism becomes a shadow of the prism from the light source bulb 4 more than a certain prism. Light enters only the tip of the prism. Moreover, since the tip of the prism is round as described above, there is a loss of light. For this reason, in the vehicular lamp in which the above-described inner lens 2 is used, when viewed from the front, the end portion remote from the light source bulb 4 looks dark.

In the above-mentioned inner lens 2,
It is conceivable to extend the molding time (resin supply time) or apply pressure after the resin supply to spread the resin to the tip of the reflective prism 21, but the production efficiency of the inner lens 2 is extremely low. Since it is bad, the fact is that the above-mentioned inner lens 2 having a rounded tip of the reflection system prism 21 is used.

SUMMARY OF THE INVENTION An object of the present invention is to provide an inner lens of a vehicular lamp having good light use efficiency.

[0010]

According to the present invention, in order to achieve the above object, a center surface of a reflection system prism of a Fresnel lens is provided with an effective surface on a front end side and a thick molding surface on a base side. In addition, what is done is characterized.

[0011] The inner lens of the vehicular lamp of the present invention comprises:
Since the base of the reflective prism becomes thick, the resin can be spread to the tip of the reflective prism without prolonging the molding time or applying pressure. As a result,
The tip of the reflection type prism is not rounded but becomes an acute angle. For this reason, the light incident on the tip of the prism is emitted as parallel light, so that light loss is eliminated and light use efficiency is improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an inner lens of a vehicular lamp according to the present invention will be described below with reference to FIGS. In the drawing, the same reference numerals as those in FIGS. 3 and 4 denote the same components. In the inner inner lens 2 of the vehicle lamp of the present invention in this embodiment, the surface on the center side of the reflection system prism 21 of the Fresnel lens is formed into the effective surface 212 on the distal end side and the thick molding surface 213 on the base side. , Eggplant.

In the inner inner lens of the vehicle lamp according to the present invention in this embodiment, since the base of the reflecting prism 21 is thick, the forming time is not increased, and the reflecting prism is not applied without applying pressure. The resin can be spread to the tip of 21. As a result, the tip of the reflection type prism 21 becomes an acute angle without being rounded. For this,
As shown by a solid line arrow in FIG. 1, the light incident on the tip of the prism 21 is emitted as parallel light, so that light loss is eliminated and light use efficiency is improved. That is, the light distribution performance of the vehicle lamp is improved.

In the reflection type prism 21 distant from the light source bulb 4, as described in the above-described conventional example,
Since a certain prism is more shaded by the prism from the light source bulb 4, light enters only at the tip of the prism. However, the inner lens 2 of the present invention
Since the tip of the prism has an acute angle without being rounded, light loss is eliminated. For this reason, in the vehicular lamp in which the inner lens 2 of the present invention is used, when viewed from the front, the end portion distant from the light source bulb 4 and the portion near the light source bulb 4 appear uniformly bright.

Further, as shown in FIG. 2, the base portion of the prism is expanded so as to be thick, so that the height, that is, the light total reflection side, is higher than that of a conventional prism (shown by a dotted line in FIG. 2). Of the surface 211 increases by H. As a result, in comparison with the non-light-emitting portion D 'and the light-emitting portion L' of the conventional prism, in the prism of the inner lens 2 of the present invention, the non-light-emitting portion D is reduced by A and the light-emitting portion is reduced. L
(When the inner lens 2 is viewed from the front).

The above-mentioned effective surface 212 and the thick molding surface 2
The boundary 214 with respect to a certain prism is located closer to a certain prism than a position 215 that is a shadow of the prism from the light source bulb 4, and the position is also determined by the central prism and the peripheral prism. different. Further, the above-described thick molding surface 213 may be a flat surface or a curved surface. in short,
What is necessary is just to increase the thickness of the base of the prism.

[0017]

As is apparent from the above description, the inner lens of the vehicular lamp according to the present invention has the center surface of the reflective prism of the Fresnel lens, the effective surface on the distal end side, and the thick molding surface on the base side. However, since it is done, the base of the reflective prism becomes thick, and as a result, the molding time is lengthened,
The resin can be spread to the tip of the reflective prism without applying pressure. For this reason, the tip of the reflective prism becomes an acute angle without being rounded, and the light incident on the tip of the prism is emitted as parallel light, light loss is eliminated, and light use efficiency is improved. In addition, the end portion remote from the light source bulb and the portion near the light source bulb appear uniformly bright. Further, the number of non-light emitting portions decreases and the number of light emitting portions increases.

[Brief description of the drawings]

FIG. 1 shows an embodiment of an inner lens of a vehicular lamp according to the present invention, and is an explanatory diagram of an optical path in a reflective prism.

FIG. 2 is an explanatory diagram of a non-light emitting portion and a light emitting portion using an inner lens according to the present invention and a non-light emitting portion and a light emitting portion using a conventional inner lens.

FIG. 3 is a cross-sectional view of a vehicle lamp using a conventional inner lens.

FIG. 4 is an enlarged cross-sectional view of an IV section in FIG. 3 showing an optical path in a reflective prism.

[Explanation of symbols]

1. Lamp lamp housing 2. Inner lens 2.
DESCRIPTION OF SYMBOLS 1 ... Reflection prism, 211 ... Opposite surface (surface on the total reflection side), 212 ... Effective surface (center side (light incident side surface)), 213 ... thick molding surface (center side surface) ), 214 ...
Boundary, 215 ... Shadow, 3 ... Outer lens, 4
... light source bulb, D: non-light emitting part, L: light emitting part.

Claims (1)

[Claims] 1. An inner lens of a vehicle lamp comprising a Fresnel lens for emitting incident light from a light source bulb as parallel light, wherein a surface of a center of a reflection system prism of the Fresnel lens is
An inner lens for a vehicle lamp, wherein the inner surface is formed between an effective surface on a distal end side and a thick molding surface on a base side.