JPH10253402A - Instrument lighting system - Google Patents

Abstract

(57) [Problem] To provide a lighting device for an instrument, in which light is prevented from leaking out of the pointer cap without increasing cost by improving a light guide plate. A concave surface (15) inclined downward toward an opening (13) is formed on a surface of a light guide plate (6) attached to the back surface of a dial (4) opposite to a reflection end surface (14). When the light is reflected and illuminated from the reflecting end face 14 to the pointer 11 for illumination, the light is bent inward by the concave face 15 and the cap 12 is bent.
Light leakage to the outside was prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device for an instrument for illuminating a pointer such as an instrument for an automobile, and more particularly to a lighting device for an instrument having a light guide plate for guiding light from a light source to a pointer. .

[0002]

2. Description of the Related Art FIG. 3 shows an example of a conventional instrument lighting device.

A light guide plate 6 made of a transparent resin is attached to the back surface of the dial 4, and a light source (not shown) such as a bulb is arranged at a light introducing portion at an end of the light guide plate 6.

A cap 12 of a pointer 11 arranged on the dial 4 is fitted into a pointer shaft 10 of an inner machine (not shown). A tapered reflection end surface 14 is formed on the end surface of the opening 13 of the prism 6 through which the pointer shaft 10 passes.

The light A of the light source introduced into the light guide plate 6 is reflected upward by the reflection end face 14 and illuminates the pointer 11 via the cap 12.

[0006]

SUMMARY OF THE INVENTION Light A passing through the light guide plate 6
Contains a lot of diffusely reflected light in addition to parallel light. Therefore, the light reflected by the reflection end face 14 is not only parallel light, but also
Diffusely reflected light is generated that is diffusely reflected in an oblique direction.

Generally, a gap 7 is provided between the cap 12 of the pointer 11 and the light guide plate 6, and the larger the gap 7, the more diffusely reflected light escapes through the gap 7, and this is outside the pointer 11. Light leakage a. This light leakage a corresponds to this if there is a look back on the side of the windshield of the instrument,
If there is no or too small a reflection, it will hit the windshield and reflect. The light hitting the windshield is reflected into the eyes and obstructs the field of view, making the dial 4 difficult to see.

In order to prevent this, conventionally, measures have been taken such as increasing the look and absorbing light leakage a, or printing on the dial 4 and the light guide plate 6, but the manufacturing process is complicated. Therefore, there is a problem that cost increase cannot be avoided.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides an instrument lighting device in which light is prevented from leaking out of a pointer cap without increasing costs by improving a light guide plate. With the goal.

[0010]

In order to achieve the above-mentioned object, the invention according to claim 1 introduces light from a light source into a light introduction portion of a light guide plate attached to the back of a dial, and the light guide plate is provided with the light guide plate. A lighting device for an instrument for reflecting and illuminating light from a reflection end surface of an opening formed in a plate to a pointer, and illuminating the light guide plate with a downward slope toward a surface corresponding to the reflection end surface of the light guide plate. A concave surface is formed.

Therefore, according to the first aspect of the present invention, the light of the light source passes through the light guide plate, is reflected by the reflection end face, and illuminates the pointer through the cap. At this time, the light reflected by the reflection end face is forcibly bent inward by the concave surface, so that light leakage to the outside of the cap can be eliminated.

According to a second aspect of the present invention, in the instrument lighting device according to the first aspect, the concave surface has a conical shape inclined downward toward the opening. is there.

Therefore, according to the second aspect of the present invention, all the diffusely reflected light generated around the opening of the light guide plate can be bent inward to prevent light leakage to the outside of the cap.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. The same members or those having the same functions as those in FIG. 3 are denoted by the same reference numerals.

In FIG. 1, a wiring board 2 is mounted on a bottom plate of a case 1 of an instrument.
Is attached. The dial 4 is attached to a dial 5 of the instrument, and a light guide plate 6 made of a transparent acrylic resin or the like is attached to the back of the dial 4.

The light guide plate 6 has a light introducing portion 6a formed at an end thereof, and a light source 8 such as a bulb is disposed at an end of the light introducing portion 6a. A cap 12 of a pointer 11 arranged on the dial 4 is fitted into the pointer shaft 10 of the inner unit 3. Below the opening 13 of the light guide plate 6 through which the pointer shaft 10 passes, the conical reflection end face 1 whose inner diameter decreases upward.
4 are formed.

The upper side (front side) of the opening 13 of the light guide plate 6
The opening 13 is provided at a position corresponding to the reflection end face 14.
Conical shape inclined downward toward the so-called conical concave surface 1
5 are formed (see FIG. 2).

The light of the light source 8 received by the light introducing section 6a is:
The light passes through the light guide plate 6, is reflected upward by the reflection end face 14, and illuminates the pointer 11 via the cap 12. At this time, the light reflected from the reflection end face 14 is forcibly bent inward by the concave surface 15, that is, in the direction of the cap 12, so that light leakage to the outside of the cap 12 is eliminated. Therefore, even if the irregularly reflected light exits from the reflection end face 14, it is bent by the concave surface 15 and is all emitted toward the cap 12.

Further, by forming the concave surface 15 into a conical mortar shape, all the irregularly reflected light generated around the opening 13 can be bent inward.
Since light can be prevented from leaking outside the light source 2 and the light can be concentrated on the cap 12, the pointer can be efficiently illuminated.

As described above, the instrument lighting device according to the present embodiment can eliminate the light leaking out of the pointer 11 due to the irregularly reflected light by forming the concave surface 15 in the light emitting portion of the light guide plate 6. There is no reflection of the instrument on the windshield due to light leakage, and the visibility is not obstructed. Further, with a simple configuration in which only the concave surface 15 is formed, processing such as addition of new parts or printing is not required. Therefore, it can be manufactured at low cost. In addition, there is no need to provide a means for increasing the look to prevent reflection on the windshield.

[0021]

As described above in detail, according to the first aspect of the present invention, since the concave surface is formed on the surface opposite to the reflective end surface at the periphery of the opening of the light guide plate, the light is reflected from the reflective end surface. The emitted light is forcibly bent inward by the concave surface, so that light leakage to the outside of the cap can be eliminated. Therefore, there is no reflection of light on the windshield of the instrument due to light leakage, and the visibility is not obstructed. In addition, with a simple configuration that only forms a concave surface, processing such as addition of new parts or printing is not required. Therefore, it can be manufactured at low cost. In addition, there is no need to provide a means for increasing the look to prevent reflection on the windshield, thereby increasing the degree of freedom in instrument design.

According to the second aspect of the present invention, since the concave surface has a conical shape inclined downward toward the opening, all the irregularly reflected light generated at the periphery of the opening is bent inward, so that the cap is bent. Light leakage from the surroundings can be eliminated, and light can be concentrated on the cap, so that pointer lighting can be performed efficiently.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of the present invention.

FIG. 2 is a plan view of a main part of FIG.

FIG. 3 is a vertical sectional side view of a main part of a conventional instrument lighting device.

[Explanation of symbols]

 4 Dial 6 Light guide plate 8 Light source 11 Pointer 13 Opening 14 Reflecting end face 15 Concave face

Claims (2)

[Claims] 1. A light guide from a light source is introduced into a light introducing portion of a light guide plate attached to the back of a dial, and light is reflected from a reflective end face of an opening formed in the light guide plate to a pointer to illuminate the pointer. A lighting device for an instrument, wherein a concave surface inclined downward toward the opening is formed on a surface side of the light guide plate corresponding to the reflection end surface. 2. The instrument lighting device according to claim 1, wherein the concave surface has a conical shape inclined downward toward the opening.