JP2574407Y2 - Light guide plate - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate, and more particularly to a light source provided on the back of a dial of a pointer-type instrument panel such as an instrument used for a combination meter of a vehicle. The present invention relates to a light guide plate that guides and emits a pointer by itself.

[0002]

2. Description of the Related Art Conventionally, in an analog instrument for displaying a state quantity by a pointer, for example, an analog instrument such as a speedometer or an engine tachometer provided in a combination meter of an automobile, a viewer such as a driver is required to observe the situation. The state quantity is determined by reading the scale of the dial located at the tip of the pointer of the instrument.

In such a pointer-type instrument, a scale design is conventionally formed on the dial of the instrument, and a meter inner machine is attached to the back side of the scale design, and a pointer is attached to the front side so that the scale design is indicated by the pointer. It has become. The pointer in such a pointer-type instrument has conventionally been made of a member such as a metal, but in recent years, with the aim of improving nighttime visibility of the pointer, the pointer is made of a transparent material, and the back of the dial is used. The light from the light source provided in the above is guided to the pointer using a light guide plate, and the pointer itself emits light (hereinafter referred to as self-emission). Also, the scale of the dial of the instrument is illuminated using the light guide plate.

FIG. 4 illustrates the structure of a light-emitting mechanism of a pointer of a conventional pointer-type instrument having such a self-luminous pointer. In the figure, reference numeral 40 denotes an inner unit of the meter, 41 denotes a rotating shaft of the inner unit 40, 42 denotes a pointer cap attached to the rotating shaft 41, 43 denotes a pointer made of a transparent resin such as acrylic protruding from the pointer cap 42, Reference numeral 44 denotes a dial plate of an instrument provided with a scale 45, and reference numeral 46 denotes a light guide plate made of a transparent resin for guiding light from a light source 47 to the base rear surface of the pointer cap 42.
The light guide plate 46 is generally fixed to the front of the inner unit 40 by screws 48.

When the light source 47 is turned on, the illumination light emitted from the light source 47 is transmitted from the light receiving surface 46a of the light guide plate 46 to the light guide plate 46.
Get in. Then, the light travels in the direction of the arrow in the light guide plate 46 while being reflected in the light guide plate 46, and is reflected in the direction of the pointer cap 42 by the reflection surface 46 b provided at the end thereof. The illumination light reflected by the reflection surface 46 b exits from the light guide plate 46 and is exposed from the end of the pointer 43 exposed on the lower surface of the pointer cap 42 to the pointer 4.
3, the light is reflected in the pointer 43, advances inside the pointer 43 toward the distal end, and exits from the front side of the pointer 43.
Appear to be self-luminous.

[0006]

However, in such a conventional instrument provided with a self-luminous pointer, a screw hole (round) for inserting a screw 48 into the optical path of the illumination light in the light guide plate 46 is provided. Since the holes (holes) 10 are provided, the illumination light hitting the screw holes 10 is reflected or refracted.
There is a problem that the light emission luminance of the light emitting device is reduced.

This problem will be described in more detail with reference to FIG. FIG. 5A shows the shape of the screw hole 10 provided in the light guide plate 46. As can be seen from FIG. 5A, the screw hole 10 is a round hole,
a, and a reduced diameter portion 10b through which the screw portion 48b of the screw 48 is inserted. The enlarged diameter portion 10a is a considerably large round hole.

[0008] Therefore, as shown in FIG.
Of the illumination light traveling toward the reflecting surface 46b in the light 6, the one that hits the enlarged diameter portion 10a is reflected by the wall surface of the enlarged diameter portion 10a as indicated by reference numeral A, or is indicated by reference numeral B. Illuminating light that does not reach the reflecting surface 46b. As a result, the amount of illumination light guided to the reflection surface 46b decreases, and the light emission luminance of the pointer 43 decreases.

In view of the above, the present invention reduces the degree of reduction in the amount of illumination light reaching the reflecting surface even if there is a screw hole in the light path of the illumination light of the light guide plate in a light guide plate used for an instrument having an illumination pointer. It is another object of the present invention to provide a light guide plate capable of suppressing a decrease in light emission luminance of a pointer.

[0010]

According to the present invention, there is provided a light guide plate for illuminating at least a transparent resin pointer of a meter by a light source provided in a case of the pointer type meter. A light guide plate provided between the dial of the meter and the inner machine, the light receiving surface for introducing illumination light from the light source into the light guide plate, and the light receiving surface
Reflects part of the illumination light introduced from above toward the base of the pointer
A deflection surface, and a reflection surface for reflecting illumination light that has traveled in the light guide plate toward the base of the pointer.In the light guide plate, the illumination light incident from the light receiving unit is not reflected and a direct light path reaching directly to the reflecting surface, wherein there is a reflecting optical path portion of the incident illumination light reaches the reflective surface after being reflected once by the deflecting surface from the light receiving unit, further, these direct light path and the reflection light path A screw hole for inserting a screw for fixing the light guide plate to the front side of the inner unit is provided in the middle of the screw hole. A first side surface on which the illuminating light traveling in the direct optical path is perpendicularly incident, and a second and a third side which are parallel to the illuminating light traveling in the reflected optical path.
And formed in a polygonal column shape having the following side surfaces. In addition, it is preferable that the enlarged diameter portion further includes a fourth side surface parallel to the first side surface.

[0011]

According to the light guide plate of the present invention, when illumination light that reaches the reflection surface without being reflected from the light receiving portion of the light guide plate and hits the screw hole, the illumination light is reflected by the screw hole. Since the first side surface is at a right angle, the illumination light travels straight without refraction, and further travels straight without refraction on the fourth side surface parallel to the first side surface. Light does not decrease. Also, after entering from the light receiving section ,
Illumination light that reaches the reflecting surface after being reflected at a high degree is less likely to hit the screw hole because a part of the screw hole is shaved so as to be parallel to the reflected light to form the second and third side surfaces. That is, a decrease in illumination light reaching the reflection surface is suppressed.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a light guide plate according to the present invention; The light guide plate of the present invention is also used in the pointer-type instrument provided with the self-luminous hands described with reference to FIG. 4, and, like the conventional light guide plate 46, the inner device 40 and the dial 44 of the meter. And is fixed to the front surface of the inner unit 40 by screws 48. When the light source 47 is turned on, the illumination light emitted from the light source 47 is applied to the pointer cap 4.
It is used to guide the pointer 43 in a self-luminous direction.

FIG. 1A is a partial plan view showing a configuration of a screw hole 10 in one embodiment of the light guide plate of the present invention.
FIG. 1B is a perspective view of FIG.

As shown in FIGS. 1 (a) and 1 (b), the screw hole 10 of this embodiment also has a screw head 4 of a screw 48 shown in FIGS.
An enlarged diameter portion 10a for receiving the screw 8a and a reduced diameter portion 10b for inserting the screw portion 48b are provided. In this embodiment, the shape of the reduced diameter portion 10b is a round hole as in the conventional example, but the shape of the enlarged diameter portion 10a is not a round hole. That is, in this embodiment, the enlarged diameter portion 1
0a is the first side surface 11, the second side surface 12, the third side surface 1
3 and a trapezoidal column with a fourth side surface 14.

The first side surface 11 corresponds to the light guide plate 4 shown in FIG.
No. 6 from the light receiving portion 46a, the reflection surface 46b without reflection
Is perpendicular to an optical path (hereinafter, referred to as a direct optical path) of the illumination light (indicated by reference symbol S in FIG. 1). Further, the fourth side surface 14 is parallel to the first side surface 11. Therefore, the illuminating light S, which has directly traveled along the optical path, travels in the enlarged diameter portion 10a without being refracted even if it hits the first side surface 11, enters the light guide plate again without being refracted from the fourth side surface 14, and Go straight to the reflective surface.

The second side surface 12 corresponds to the light guide plate 4 shown in FIG.
The light path (indicated by a symbol R1 in FIG. 1) of the illumination light (indicated by R1 in FIG. 1) after being incident from the light receiving portion 46a of the light source 6 and directly deviating to one side with respect to the optical path, reflected once by a deflecting surface (not shown), and then toward the reflecting surface 46b. Optical path). The third side surface 13, it on the other side with respect to direct light path incident from the light receiving portion 46a of the light guide plate 46 in FIG. 4, the reflecting surface 46b after once reflected by the deflecting surface (not shown)
Is parallel to the reflected light path of the illumination light (indicated by the symbol R2 in FIG. 1). Therefore, the illumination lights R1 and R2 that have traveled along two different reflected light paths are reflected light parallel to the second side surface 12 and the third side surface 13, and
It is unlikely that the light strikes the second side surface 12 and the third side surface 13, and most of the light goes straight to the reflecting surface 22 for the pointer without being reflected.

As a result, in the light guide plate having the screw hole 10 of the embodiment of FIG. 1, the illumination light which enters from the light receiving portion 46a and travels directly through the optical path, and the reflected optical path after being reflected once, is reflected by the reflecting surface 46.
The possibility that the illuminating light directed to b deviates from the optical path due to refraction or reflection is reduced, and a decrease in the light emission luminance of the pointer is suppressed.

FIG. 2A is a plan view of the entire light guide plate showing another embodiment of the light guide plate of the present invention, and FIG. 2B is an enlarged view of a part of FIG. The light guide plate 20 in this embodiment is also provided between the dial plate of the instrument and the inner unit in order to illuminate at least the transparent resin pointer of the instrument with illumination light from a light source provided in the case of the pointer-type instrument. It is fixed to the front side of the internal unit by screws.

In FIG. 2A, reference numeral 21 denotes a light receiving surface for introducing illumination light from a light source 27 into the light guide plate 20;
Reference numeral 2 denotes a reflecting surface for reflecting the illumination light traveling inside the light guide plate 20 toward the base of the pointer, and reference numerals 23 and 24 reflect the illumination light traveling inside the light guide plate 20 in a direction other than the base direction of the pointer to form a pointer. A deflecting surface that reflects in the base direction, R1 is reflected light that is reflected by the deflecting surface 23 and travels along a reflected light path, and R2 is a deflecting surface 24.
S is reflected light that travels along the reflected light path after being reflected by S, and S is reflected light that travels directly through the optical path. Reference numeral 30 denotes a screw hole for inserting a screw for attaching the light guide plate 20 to the internal machine.

As shown in FIG. 3, the screw hole 3 of this embodiment is
4 includes an enlarged diameter portion 30a for receiving the screw head 48a of the screw 48 shown in FIGS. 4 and 5, and a reduced diameter portion 30b for inserting the screw portion 48b. In this embodiment, the shape of the reduced diameter portion 30b is a round hole as in the conventional example, but the shape of the enlarged diameter portion 30a is not a round hole. That is, in this embodiment, the enlarged diameter portion 30a is formed between the first side surface 31, the second side surface 32, the third side surface 33, the fourth side surface 34, and the first side surface 31 and the second side surface 32. Fifth side 35, first side 31, and third side 33
It has a hexagonal column shape with a sixth side surface 36 located between them.

The first side surface 31 corresponds to the light guide plate 4 shown in FIG.
No. 6 from the light receiving portion 46a, the reflection surface 46b without reflection
Is perpendicular to the direct optical path through which the illumination light S travels. Further, the fourth side surface 34 is parallel to the first side surface 31. Therefore, the illuminating light S, which has directly traveled along the optical path, travels in the enlarged diameter portion 10a without being refracted even when it hits the first side surface 31, and enters the light guide plate again without being refracted from the fourth side surface 34, To the reflection surface 22 to the right.

The second side surface 32 corresponds to the light guide plate 4 shown in FIG.
6 is directly incident on one side with respect to the optical path from the light receiving portion 46a , and once reflected by the deflecting surface 23, the reflecting surface 46b
The illumination light R1 traveling toward is parallel to the reflected light path. Similarly third aspect 33, it on the other side with respect to direct light path incident from the light receiving portion 46a of the light guide plate 46 in FIG. 4, the reflecting surface 46 after being reflected once by the deflecting surface 24
The illumination light R2 traveling toward the point b is parallel to the reflected light path. Therefore, the illumination lights R1 and R2 that have traveled along two different reflected light paths are the second side face 32 and the third side face 3
3 is reflected light parallel to the second side surface 32.
And there is little possibility of reflection on the third side surface 33, and most of the light goes straight to the reflection surface to the pointer without reflection.

As a result, even in the light guide plate having the screw hole 30 in the embodiment of FIG. 2, the illumination light which enters from the light receiving portion 46a and travels directly through the optical path, and the reflected light path after being reflected once by the deflecting surfaces 23 and 24, are not reflected. The possibility that the illuminating light traveling toward the reflecting surface 46b deviates from the optical path due to refraction or reflection is reduced, and a decrease in the light emission luminance of the pointer is suppressed.

FIG. 3B shows still another embodiment of the light guide plate of the present invention, in which the length of the fourth side surface 14 of the trapezoidal screw hole 10 shown in FIG. 1A is reduced to zero. 3 shows the shape of the screw hole 50 thus formed. In the screw hole 50 of this embodiment, since the fourth side surface 14 is not provided, the illumination light S is refracted at the second side surface 12 and the third side surface 13, so that the illumination light S is compared with the screw hole 10 in the embodiment of FIG. The brightness of the pointer will be slightly reduced.

[0025]

As described above, according to the light guide plate of the present invention, in the light guide plate used for the instrument provided with the illumination pointer, even if the screw hole is provided in the optical path of the illumination light of the light guide plate,
There is an effect that the degree of decrease in the amount of illumination light reaching the reflecting surface can be reduced, and a decrease in the luminance of the pointer can be suppressed.

[Brief description of the drawings]

1A is a partial plan view of a light guide plate showing an embodiment of the light guide plate of the present invention, and FIG. 1B is a perspective view of FIG.

2A is a plan view of the entire light guide plate showing another embodiment of the light guide plate of the present invention, and FIG. 2B is an enlarged view of a part of FIG.

3 (a) is a partially enlarged plan view showing an enlarged shape of a screw hole in the embodiment of FIG. 2, and FIG. 3 (b) is a shape of a screw hole in still another embodiment of the light guide plate of the present invention. It is a partial enlarged plan view which expands and shows.

FIG. 4 is a cross-sectional view showing the structure of a conventional self-luminous pointer-type instrument.

5 (a) is a perspective view showing the shape of a conventional screw hole provided in the light guide plate of FIG. 4, and FIG. 5 (b) reduces illumination light reaching the reflecting surface by the screw hole of FIG. It is explanatory drawing explaining a situation.

[Explanation of symbols]

 10, 30 Screw hole 10a Large diameter portion 10b Reduced diameter portion 11, 31 First side surface 12, 32 Second side surface 13, 33 Third side surface 14, 34 Fourth side surface 20 Light guide plate 21 of the present invention 21 Light receiving surface Reference Signs 22 Reflecting surface 23, 24 Deflection surface 40 Inner machine 41 Rotation axis 42 Pointer cap 43 Pointer 44 Dial 45 Scale 46 Light guide plate 47 Light source 48 Screw R1, R2 Illumination light of reflection optical path S Illumination light of direct optical path

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01D 11/28 G12B 11/00

Claims (2)

(57) [Scope of request for utility model registration] 1. An instrument provided between a dial of an instrument and an inner machine for illuminating at least a transparent resin pointer of the instrument with illumination light from a light source provided in a case of the instrument. a light guide plate, a light receiving surface for introducing illumination light to the light guide plate from the light source, the light receiving surface
Reflects part of the illumination light introduced from above toward the base of the pointer
A deflection surface, and a reflection surface for reflecting illumination light that has traveled in the light guide plate toward the base of the pointer.In the light guide plate, the illumination light incident from the light receiving unit is not reflected and a direct light path reaching directly to the reflecting surface, wherein there is a reflecting optical path portion of the incident illumination light reaches the reflective surface after being reflected once by the deflecting surface from the light receiving unit, further, these direct light path and the reflection light path A screw hole for inserting a screw for fixing the light guide plate to the front side of the inner unit is provided in the middle of the screw hole. And the diameter increasing portion is configured to travel through the direct optical path .
A first side surface on which illumination light is vertically incident, and the reflected light path
A light guide plate formed in a polygonal column shape having second and third side surfaces that are parallel to the illumination light that travels . 2. The light guide plate according to claim 1, wherein the enlarged diameter portion further has a fourth side surface parallel to the first side surface.