JPH09287981A - Photoconducting apparatus and display device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively guide the light of a substantially linear light emitting element into a photoconducting plate, without increasing the thickness of the plate. SOLUTION: V-shaped grooves 331 to 333, 341 to 343 are formed on the rear surface 3b of a photoconducting plate 3, and oblique surfaces 31, 32 are formed on the front surface of the plate 3. The surfaces 31, 32 and the inclining angle of the inner wall surfaces 331a to 333a, 341a to 343a are set to the surface 3b of the plate 3 so that the lights incident from the surfaces 331a to 333a, 341a to 343a opposite a cold cathode fluorescent lamp 2 can be substantially totally reflected at the surfaces 31, 32 in the grooves 331 to 333, 341 to 343. Thus, the leakage of the lights from the surfaces 31, 32 can be prevented, and the light from the lamp 2 can be effectively guided to the plate 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide device and a display device using the same, and is particularly suitable for use as a display device for a vehicle equipped with a pointer.

[0002]

2. Description of the Related Art The present applicant has previously filed Japanese Patent Application No. 7-18367.
No. 4 is filed and a display device as shown in FIG. 7 is proposed. Note that FIG. 7 shows the display device 100 shown in FIG.
It is a partial view of a section. In this display device 100, a light guide plate 3 made of, for example, an acrylic resin is provided along a back surface 1b of a dial 1 having pattern light transmitting portions 51 to 54 (see FIG. 1),
A linear cold cathode fluorescent lamp 2 is provided on the back surface 3b of the light guide plate 3.
Is set up alongside.

By forming inclined surfaces 31 and 32 in the vicinity of the cold cathode fluorescent lamp 2 on the surface 3a side of the light guide plate 3, the incident angle θ1 of light on the surface 3a of the light guide plate 3 is increased. Light is prevented from leaking from the surface 3a to the outside.

[0004]

However, the inclined surface 32
In the vicinity of the other end 32b of the inclined surface 32, the inclination angle of the inclined surface 32 with respect to the back surface 3b of the light guide plate 3 is smaller than in the vicinity of the one end 32a of the inclined surface 32, and the plate thickness of the light guide plate 3 is as thin as about 5 mm. Incident angle of light θ2 near the other end 32b
However, the angle becomes smaller than the critical angle on the surface 3a of the light guide plate 3, and light leaks from the vicinity of the other end 32b of the inclined surface 32 to the outside. Therefore, there arises a problem that the light emitted from the cold cathode fluorescent lamp 2 cannot be reliably guided into the light guide plate 3. This problem similarly occurs in the reflecting surface 31.

Here, in order to totally reflect the light on the inclined surfaces 31 and 32, the thickness of the light guide plate 3 needs to be at least about three times the current thickness, which results in a high cost of the light guide plate 3. . The present invention has been made in view of the above problems, in a light guide device in which the light of the substantially linear light-emitting body is incident from the back surface of the light guide plate, without increasing the plate thickness of the light guide plate,
The purpose is to reliably guide the light of the substantially linear light-emitting body into the light guide plate.

[0006]

In order to achieve the above object, in the invention described in claims 1 to 8, the light guide plate (3) is provided.
Incident surface (331 to 333, 341 to 341) of the back surface (3b) of
43, 3e, 38a) are inclined with respect to the back surface (3b) of the light guide plate (3) so as to substantially face the substantially linear light-emitting body (2), and second inclined surfaces (331a to 333a, 341a to 3).
43a, 38a) and has an incident surface (331 to 33).
3, 341 to 343, 3e, 38a), the first inclined surface (31, 32) can be almost totally reflected on the first inclined surface (31, 32) to the back surface (3b) of the light guide plate (3). The inclined surfaces (31, 32) and the second inclined surfaces (331a-
333a, 341a to 343a, 38a) is set to an inclination angle.

Therefore, the incident surfaces (331 to 333, 341)
˜343, 3e, 38a) can be almost totally reflected on the first inclined surface (31, 32), and the light can be prevented from leaking from the first inclined surface (31, 32). The light of the light-emitting body (2) can be reliably guided into the light guide plate (3). In addition, the first inclined surface (31, 32) and the second inclined surface (331a to 333a, 341a to 343).
a, 38a), the first inclined surface (31, 32)
Since it is possible to adjust the incident angle of light in, the thickness of the light guide plate (3) can be made thinner and the cost can be reduced as compared with the case where the incident angle is adjusted only by the first inclined surfaces (31, 32). Can be planned.

The second inclined surfaces (331a to 333a,
Since 341a to 343a and 38a) substantially face the substantially linear light-emitting body (2), a larger amount of light emitted from the substantially linear light-emitting body (2) can be incident on the light guide plate (3). Also,
Since the substantially linear light-emitting body (2) is used as the light source, the light incident on the light guide plate (3) can be made more uniform than the point light source,
Light can be uniformly guided over the entire surface of the light guide plate (3).

Further, in the third aspect of the invention, on the back surface (3b) of the light guide plate (3), in the vicinity of the substantially linear light-emitting body (2), parallel to the longitudinal direction of the substantially linear light-emitting body (2). A groove portion having a substantially V-shaped cross section (331 to 333, 341 to 341)
43) are formed in plural. Therefore, the plurality of groove portions (33
1-333, 341-343), inner wall surfaces (331a-333a, 341) facing the substantially linear light-emitting body (2).
a to 343a), the inclination angle of each can be changed according to the inclination angle of the first inclined surface (31, 32),
It is possible to more effectively prevent light leakage from the first inclined surface (31, 32).

Particularly, in the invention described in claim 4, the groove portions (331 to 333, 341 to 343) are formed in the light guide plate (3).
Since it is formed on the inner side of the back surface (3b) in the plate thickness direction, the light guide plate (3) is thinner and the cost can be further reduced. Also, the back surface (3b) of the light guide plate (3)
When the printing unit is provided on the entire surface of the back surface (3b) of the light guide plate (3), printing can be performed at one time, which facilitates the printing process.

In the invention according to claim 5, the reflective layer (at least on the rear surface (3b) of the light guide plate (3) except for the incident surfaces (331 to 333, 341 to 343, 3e, 38a)). 35), and the reflector (10) is provided along the substantially linear light-emitting body (2). Therefore,
Using the above-mentioned light guide device in which a larger amount of light from the substantially linear light-emitting body (2) is guided into the light guide plate (3), the light inside the light guide plate (3) is reflected by the reflection plate (10) and the reflection plate (3). In the layer (35), the pattern light-transmitting portions (51 to 54) can be illuminated by reflecting the light to the pattern light-transmitting portions (51 to 54). It can be improved and can be easily seen by the viewer.

Further, the amount of light incident from the reflection plate (10) to the pattern light transmitting portions (51 to 54) is determined by the reflection layer (35) on the back surface (3b) of the light guide plate (3). (5
The reflectance of the reflection plate (10) is set so as to be substantially the same as the amount of light incident on the inclined surfaces (31, 54) in the pattern light transmitting portions (51-54).
It is possible to prevent the portion substantially facing 32) from becoming brighter than the pattern light-transmitting portions (51 to 54) other than this portion,
It is possible to uniformly illuminate the entire surface of the pattern light-transmitting portion (51 to 54).

Further, the light from the substantially linear light-emitting body (2) is guided by the light guide plate (3), and this light can illuminate the entire pattern display portions (51 to 54). Therefore, even if the shape or position of the pattern display portions (51 to 54) is changed, it is not necessary to change the position or shape of the substantially linear light-emitting body (2). Furthermore, since the substantially linear light-emitting body (2) is used as a light source, the light incident on the light guide plate (3) can be made more uniform than that of a point light source, and thus the pattern display portions (51 to 5).
4) can be irradiated more uniformly.

Particularly, in the invention according to claim 6, since the color of the reflector (10) is gray and achromatic, the color tone of the light emitted from the substantially linear light-emitting body (2) is not changed. The amount of light reflected by the reflector (10) can be suppressed.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention shown in the drawings will be described. (First Embodiment) The first embodiment will be described with reference to FIGS.
As shown in, pointers 61, 62, 63, 64 (hereinafter, 6
1 to 64), the present invention is applied to a display device 100 for a vehicle. The display device 100 is attached to an instrument panel on the front side of the driver's seat in the passenger compartment. In FIG. 1, the front side of the drawing is the driver's seat side, and the vertical direction of the drawing corresponds to the vertical direction of the vehicle.

The dial 1 is a plate member having a substantially rectangular shape, and is a transparent plate member 11 on which a black printing layer 12 is formed. Then, the pattern printing portions 51 to 54 are formed on the dial 1 by punching out the black print layer 12 corresponding to the pattern transmitting portions 51 to 54. The center of the dial 1 faces the approximate center of the driver's seat. Pattern translucent part 5
1 is an arc-shaped rotational speed scale pattern representing the engine rotational speed scale and the unit of engine rotational speed (× 1000 RP).
It is composed of a rotational speed unit pattern representing M).
The pattern light transmitting portion 52 is configured by an arcuate vehicle speed scale pattern representing a scale of vehicle speed and a vehicle speed unit pattern representing a unit of vehicle speed (km / h).

The pattern light-transmitting portion 53 is composed of an arcuate water temperature scale pattern and a water temperature mark which represent the scale of the water temperature. The pattern light-transmitting portion 54 is composed of an arc-shaped fuel scale pattern and a fuel mark that represent the scale of the fuel amount. The instruction display section in the claims means the scale pattern, the unit pattern, and the mark.

The light guide plate 3 is a substantially rectangular plate member smaller than the dial 1, and is made of a transparent light guide material such as transparent acrylic resin. The light guide plate 3 is mounted along the back surface 1b of the dial plate 1. Then, on the back surface 3b of the light guide plate 3, a cold cathode fluorescent lamp (substantially linear light emitting body) 2 having a length similar to the length of the light guide plate 3 in the longitudinal direction is mounted. The cold cathode fluorescent lamp 2 is arranged on the back surface 3b of the light guide plate 3 slightly closer to the upper end 3c side than the central portion in the longitudinal direction of the light guide plate 3. The cold cathode fluorescent lamp 2 emits light at the same time when the vehicle ignition switch is turned on.

On the surface 3a of the light guide plate 3, inclined surfaces (first inclined surface) 31, 3 are provided along the longitudinal direction of the cold cathode fluorescent lamp 2.
2 is formed. The inclined surfaces 31 and 32 are located at one ends 31a and 32a (positions facing the cold cathode fluorescent lamp 2 in the light guide plate 3) to other ends 31b and 32b (positions away from the cold cathode fluorescent lamp 2 in the light guide plate 3). As it goes, the light guide plate 3 is inclined so that the thickness thereof gradually increases. The inclined surfaces 31, 32 are the inclined surfaces 31, 32.
Are formed in line symmetry with respect to the ends 31a and 32a.

Further, on the back surface 3b of the light guide plate 3, at a position farther from the cold cathode fluorescent lamp 2 than the facing surface (incident surface) 3e that substantially faces the cold cathode fluorescent lamp 2, a notch portion 33 having a sawtooth cross section is formed. , 34 are formed along the longitudinal direction of the cold cathode fluorescent lamp 2. As shown in FIG. 3, the notched portions 33 and 34 have a plurality of V-shaped sections, for example, three V-shaped portions.
It is formed from the V-shaped groove portions (incident surface) 331 to 333 and 341 to 343. The notches 33 and 34 are formed on the inclined surface 3
It is formed in line symmetry with respect to the ends 31a, 32a of the first and the second parts 32, 32.

The back surface 3b of the light guide plate 3 has a notch 33,
In the state where 34 is not formed, the inclined surfaces 31 and 32 are formed on the surface 3 a of the light guide plate 3 at the portion where the light incident into the light guide plate 3 leaks. Here, the V-shaped groove 3
31-333, 341-343, inner wall surfaces 331a-333a, 341a facing the cold cathode fluorescent lamp 2.
˜343a is the second inclined surface in the claims.

The V-shaped groove portions 331 to 333, 34
The inclined surfaces 31, 32 with respect to the back surface 3b of the light guide plate 3 and the light incident from the opposing surfaces 3e can be substantially totally reflected by the inclined surfaces 31, 32, and
The inclination angles of the inner wall surfaces 331a to 333a and 341a to 343a are set. In addition, in this embodiment, the inclined surfaces 31 and 32 and the inner wall surface 38a are shown instead of the inclination angles of the inclined surfaces 31 and 32 and the inner wall surfaces 331a to 333a and 341a to 343a with respect to the back surface 3b of the light guide plate 3.
Shows the dimensions described later.

As shown in FIG. 4, the inclined surface 31 has a width W1.
And a flat surface portion 312 having a width W2. Most of the light that enters the facing surface 3e enters the curved surface portion 311 of the inclined surface 31 and is totally reflected by the curved surface portion 311. Most of the light incident on the inner wall surfaces 331a to 333a is incident on the flat surface portion 312 of the inclined surface 31 and is totally reflected by the flat surface portion 312. Similarly, the inclined surface 32 and the curved surface portion 321 and the flat surface portion 3 are also included.
22. The critical angle of the inclined surfaces 31, 32 of the light guide plate 3 made of acrylic resin is 42 °.
9 ', and the inclined surfaces 31, 32 at an angle greater than this critical angle
When light is incident on, total reflection occurs.

Specifically, in this embodiment, the thickness T of the light guide plate 3 is 5 mm, and the height D1 of the inclined surfaces 31 and 32 is 4.5 m.
m. The width W1 of the curved surface portion 311 is 5.91 mm, the height D2 is 3.58 mm, and the cross-sectional shape of the curved surface portion 311 is a part of an arc shape having a radius of 8.19 mm. Flat part 312
Has a width W2 of 8.47 mm and a height D3 of 0.92 mm, and the plane portion 312 has a linear cross section.

The depth D4 of the V-shaped groove 341 is 0.
97 mm, inner wall surface 341a with respect to the back surface 3b of the light guide plate 3
The inclination angle (hereinafter referred to as the inclination angle) θ1 is 38 ° 2
8 ', the depth D5 of the V-shaped groove 342 is 0.71 mm, the inclination angle θ2 of the inner wall surface 342a is 30 °, the V-shaped groove 34
The depth D6 of No. 3 is 0.91 mm, and the inclination angle θ3 of the inner wall surface 343a is 30 °. Then, the V-shaped groove portions 331 to 3
33 is also configured similarly to the V-shaped groove portions 341 to 343.

Further, as shown in FIG. 3, on the back surface 3b of the light guide plate 3, the facing surface 3e and the V-shaped groove 331 are formed.
The white reflective layer 35 is formed on the portions other than the layers 333 to 341 and 341 to 343. The reflective layer 35 is used for the light guide plate 3
The pattern light-transmitting parts 51 to 5 of the dial 1 for guiding the light guided inside
It plays the role of reflecting to 4. As shown in FIG. 2, the cover member 4 is made of a light-shielding material such as white polypropylene, and the back surface 3 b of the light guide plate 3 is covered by the cover member 4.
Is covered. This cover member 4 has a substantially bowl shape,
V-shaped groove portions 331 to 333 of the light guide plate 3,
Through holes 41 are formed so as to surely expose 341 to 343 and the facing surface 3e. As a result, on the back surface 3b of the light guide plate 3, the V-shaped groove portions 331 to 333, 3 are formed.
The light of the cold cathode fluorescent lamp 2 enters from only 41 to 343 and the facing surface 3e. Then, the through hole 41
An annular protruding portion 42 is formed on the outer peripheral portion of the so as to protrude substantially vertically from the outer peripheral portion.

The cold cathode fluorescent lamp 2 is held by the reflection plate 10 mounted on the inner peripheral portion of the annular protrusion 42 of the cover member 4. Here, the amount of light reflected by the reflective plate 10 to the pattern transmissive portions 51 to 54 is the amount of light reflected by the reflective layer 35 on the back surface 3 b of the light guide plate 3 to the pattern transmissive portions 51 to 54 of the dial 1. To be almost the same as
The reflectance of the reflector 10 is set. The reflection plate 1
The reflectance is adjusted by adjusting the brightness of 0, and in the present embodiment, the reflector 10 is formed of a gray material that satisfies the above reflectance.

The reflecting plate 10 includes a reflecting portion 101 having a substantially arcuate cross section, and mounting portions 102 formed at the upper and lower ends in the longitudinal direction of the reflecting portion 101. The mounting portion 102 covers the cover member. 4 annular protrusion 42
It is installed inside the. Further, as shown in FIG. 1, the display device 100 has pointers 61 to 64 for indicating vehicle speed, rotation speed, water temperature, and fuel amount, and these pointers 61 to 64.
Each drive device (not shown) for driving
Each of the pointers 61 to 64 has a pattern light transmitting portion 51 to
It is designed to rotate along 54 and has pointers 61 to 6
Reference numeral 4 is a cold cathode fluorescent lamp.

The dial plate 1 and the light guide plate 3 have through-holes 111 to 11 through which the pointer shafts (not shown) of the hands 61 to 64 and the drive shafts (not shown) of the above-mentioned driving devices penetrate.
4 and through holes 321 to 324 are formed. Further, as shown in FIG. 2, an annular light-shielding plate 7 made of a light-shielding material, such as polypropylene, is attached to the outer peripheral edge of the surface 1a of the dial 1 so as to surround the hands 61 to 64. Further, the tip of the annular shading plate 7 has a transmittance of 2
Front panel 8 made of smoked material of 0% or less
Are mounted so as to cover the surface 1 a of the dial 1.
The front panel 8 hides the inside of the display device 100 when the cold cathode fluorescent lamp 2 is turned off, and serves as a black face on which only the pattern transmissive portions 51 to 54 are displayed when the cold cathode fluorescent lamp 2 emits light.

According to the display device 100 having the above structure, the display device 100 shown in FIG.
In the above, when the cold cathode fluorescent lamp 2 emits light, the light emitted from the cold cathode fluorescent lamp 2 emits light to the facing surface 3e of the back surface 3b of the light guide plate 3 and the inner wall surfaces 331a to 331 of the notched portions 33 and 34.
33a, 341a to 343a, the incident light is substantially totally reflected by the reflecting surfaces 31, 32 of the light guide plate 3,
The upper end 3c (see FIG. 2) side and the lower end 3d of the light guide plate 3
(See FIG. 2) Light is guided to the side. Further, this light is reflected again toward the center of the light guide plate 3 at the upper end portion 3c and the lower end portion 3d.

As described above, since the light once entered into the light guide plate 3 can be prevented from leaking to the outside, the light guide plate 3 is prevented.
The light emitted from the cold cathode fluorescent lamp 2 is surely guided inside,
This light is reflected by the reflection layer 35 formed on the back surface 3 b of the light guide plate 3.
Thus, the pattern transmissive portions 51 to 54 of the dial 1 can be efficiently
Is reflected to At the same time, the back surface 2b of the cold cathode fluorescent lamp 2
The light emitted by the light is incident on the reflection plate 10, and most of the incident light is reflected by the back surface 3 of the light guide plate 3 in the reflection plate 10.
The light is reflected substantially perpendicularly to b and is incident on the dial 1 substantially perpendicularly. Here, as described above, the amount of light incident on the pattern light-transmitting portions 51 to 54 from the reflecting plate 10 and the reflection layer 35 formed on the back surface 3b of the light guide plate 3 to the pattern light-transmitting portions 51 to 54. Since the amount of incident light is substantially the same, it is possible to uniformly illuminate the entire surfaces of the pattern light transmitting portions 51 to 54.

The inner wall surfaces 331a to 333a and 341a to 343 are formed in accordance with the inclination angles of the inclined surfaces 31 and 32.
Since each inclination angle of a can be changed, it is possible to more effectively prevent light leakage from the inclined surfaces 31 and 32. In addition, the inner wall surfaces 331a to 333 of the cut portions 33 and 34.
Since a and 341a to 343a substantially face the cold cathode fluorescent lamp 2, more light emitted from the cold cathode fluorescent lamp 2 can enter the light guide plate 3.

Further, since the reflection plate 10 is gray and has an achromatic color, the color tone of the light emitted from the cold cathode fluorescent lamp 2 is not changed. Further, the light emitted from the cold cathode fluorescent lamp 2 is guided by the light guide plate 3, and this light can illuminate the entire pattern light transmitting portions 51 to 54. Therefore, even if the shapes and positions of the pattern light-transmitting portions 51 to 54 are changed, it is not necessary to change the positions and shapes of the cold cathode fluorescent lamp 2.

Further, since the cold cathode fluorescent lamp 2 is used as the light source, the light incident on the light guide plate 3 can be made more uniform than that of the point light source, and the pattern light transmitting portions 51 to 54 can be illuminated more uniformly. You can (Second Embodiment) In the present embodiment, as shown in FIG.
This is a modification of the shape of the light guide plate 3 in the first embodiment. Specifically, on the back surface 3b of the light guide plate 3,
In the vicinity of the portion facing the cold cathode fluorescent lamp 2, two projecting portions 36 and 37 projecting from the back surface 3b toward the cold cathode fluorescent lamp 2 at a minute inclination angle are formed. A semicircular groove 38 having a substantially semicircular cross section is formed between the two protrusions 36 and 37 so as to face the cold cathode fluorescent lamp 2.

The width W3 of the semi-circular groove portion 38 is made larger than the diameter of the cold cathode fluorescent lamp 2, and the inner wall surface 38a of the semi-circular groove portion 38 receives the light emitted from the cold cathode fluorescent lamp 2. The second inclined surface is the incident surface on which the light is incident and is inclined with respect to the back surface 3b of the light guide plate 3 so as to substantially face the cold cathode fluorescent lamp 2. Here, the inclination angles of the inclined surfaces 31, 32 and the inner wall surface 38a are set so that almost all the light incident from the inner wall surface 38a of the semicircular groove portion 38 can be totally reflected by the inclined surfaces 31, 32 of the light guide plate 3. It is set. In the present embodiment, the light guide plate 3
Inclined surfaces 31, 32 and the inner wall surface 38 with respect to the back surface 3b of the
Instead of showing the inclination angle of a, the dimensions of the inclined surfaces 31 and 32 and the inner wall surface 38a described later are shown.

Specifically, for the light guide plate 3 having a thickness T of 5 mm, the height D1 of the inclined surfaces 31 and 32 is 4.3 mm, and the widths W4 and W5 of the inclined surfaces 31 and 32 are 6.7 mm. .
Further, the protrusion height H1 of the protrusions 36 and 37 is 2.5 mm,
The width W3 of the semi-circular groove portion 38 is 5 mm, and the depth D7 of the semi-circular groove portion 38 is 2.5 mm. In addition, the inclined surfaces 31, 3
The cross-sectional shape of 2 is a part of an ellipse having a long axis length of 36.7 mm and a short axis length of 16.1 mm.

On the back surface 3b of the light guide plate 3 except the inner wall surface 38a, a reflective layer 35 made of a white material is formed by printing or hot stamping. The portion of the cover member 4 facing the protrusions 36, 37 of the light guide plate 3 has a shape along the protrusions 36, 37. In this cover member 4,
The through hole 4 is provided in a portion of the light guide plate 3 facing the inner wall surface 38a.
1 is formed. Thereby, the back surface 3b of the light guide plate 3
At, the light of the cold cathode fluorescent lamp 2 enters from only the inner wall surface 38a. Then, the reflection plate 10 having a substantially semicircular cross section is mounted along the outer peripheral portion of the through hole 41.

According to the above construction, the light emitted from the cold cathode fluorescent lamp 2 is incident on the inner wall surface 38a of the semi-circular groove portion 38 substantially vertically, so that this light is emitted from the inner wall surface 3 of the semi-circular groove portion 38.
The surface 3 of the light guide plate 3 is hardly refracted at 8a.
It is incident on the a side. Therefore, the light from the cold cathode fluorescent lamp 2 can be more reliably incident on the surface 3a side of the light guide plate 3 at an incident angle equal to or greater than the critical angle, as compared with the first embodiment.

(Third Embodiment) In this embodiment, as shown in FIG. 6, the reflection plate 10 in the second embodiment described above.
Is integrally formed with the cover member 4 made of a white resin material, and further, the inclined surface 3 of the light guide plate 3 is formed.
A light diffusing plate (light diffusing member) having a length approximately equal to the length of the cold cathode fluorescent lamp 2 in the longitudinal direction between the dial plates 1 and 32 and the dial 1.
9 are arranged. The width V of the light diffusing plate 9 is approximately the same as the width W3 of the semi-circular groove portion 38 of the light guide plate 3, and the light diffusing plate 9 is made of a milky white material in which glass beads are mixed in a transparent material. , Plays a role of diffusing incident light. The light diffusing plate 9 is adhesively fixed to the dial 1.

Then, the amount of light incident on the portion of the pattern light-transmitting portions 51 to 54 facing the light diffusion plate 9 and the amount of light incident on the pattern light-transmitting portions 51 to 54 other than this portion are determined. The light diffusing amount of the light diffusing plate 9 is adjusted so as to be almost the same. Specifically, the light diffusion amount can be increased by increasing the mixing amount of the glass beads. In the present embodiment, since the reflection plate 10 is made of a white material having a high reflectance, the amount of light reflected by the reflection plate 10 is larger than that in the first embodiment, but this light is diffused. By diffusing the light through the plate 9, the amount of light incident on the pattern light transmitting portions 51 to 54 of the dial 1 can be suppressed.

(Other Embodiments) In the first embodiment, the cut portions 33 and 34 are formed into three V-shaped groove portions 331 to 33.
However, the present invention is not limited to this, and the number of V-shaped groove portions may be appropriately changed. For example, the number of V-shaped groove portions may be two or less, or four or more.

In the first embodiment, the light guide plate 3
Although the V-shaped groove is not formed on the facing surface 3e of the back surface 3b facing the cold cathode fluorescent lamp 2, the V-shaped groove may be formed on the facing surface 3e. Also,
The depth of the V-shaped groove portions 331 to 333, 341 to 334,
The inclination angles of the inner wall surfaces 331a to 333a and 341a to 334a may be changed appropriately.

Although both of the cut portions 33 and 34 are formed by the three V-shaped groove portions 331 to 333 and 341 to 334, the V-shaped groove portions 331 to 333 of the cut portion 34 are formed.
May be larger than the number of V-shaped groove portions 341 to 334 of the cut portion 33. As a result, the light from the cold cathode fluorescent lamp 2 is guided by the light guide plate 3 as much as the number of V-shaped grooves is increased.
Since a large amount of light can be made incident inside, more light can be guided to the lower end 3d side of the light guide plate 3.

Here, the cold cathode fluorescent lamp 2 includes a light guide plate 3
Since it is arranged closer to the upper end 1c side than the central part in the longitudinal direction of the light guide plate 3, more light is guided to the lower end part 3d side of the light guide plate 3 so that the light is uniformly guided over the entire light guide plate 3. Can shine In the first and second embodiments, the reflector 10 is made of a gray, that is, achromatic resin material. However, the present invention is not limited to this, and the reflector 10 is provided. It may be made of a coloring material.

In the first to third embodiments described above, the reflective layer 35 provided on the back surface 3b of the light guide plate 3 efficiently reflects the light to the dial plate 1. However, the back surface 3b of the light guide plate 3 is described. A grain may be provided so that light can be efficiently reflected to the dial 1 by this grain. In the second and third embodiments, the inner wall surface 38a is formed on the back surface 3b of the light guide plate 3.
The printing layer 35 is provided in a portion other than the inner wall surface 38a, and the reflection plate 10 is arranged in a portion facing the inner wall surface 38a. However, the back surface 3b of the light guide plate 3 is printed on a portion other than the inner wall surface 38a and the protrusions 36 and 37. The layer 35 may be provided, and the reflection plate 10 may be arranged in the portion facing the inner wall surface 38a and the protrusions 36 and 37. As a result, the portion where the print layer 35 is provided becomes flat, and it is not necessary to perform printing on the inclined portions such as the protrusions 36 and 37 of the light guide plate 3, so the printing process of this print layer 34 is simplified.

Further, in the third embodiment, the pattern light transmitting portions 51 to 54 are uniformly illuminated by the white reflecting plate 10 and the milky white light diffusing plate 9.
The present invention is not limited to this, and the light diffusing plate 9 may be applied to the display device 100 in which the reflecting plate 10 is made of a gray material whose reflectance is slightly lower than that of the white material. Good.

Further, in the third embodiment, the light from the reflecting plate 10 is diffused by the light diffusing plate 9, but it is integrally provided on the back surface 1b of the dial 1 facing the incident surface 34a. The light may be diffused by a drop.

[Brief description of drawings]

FIG. 1 is a plan view of a display device of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1 according to the first embodiment.

FIG. 3 is a partially enlarged view of FIG. 2;

FIG. 4 is a partially enlarged view of the light guide plate for explaining the dimensions of the light guide plate.

FIG. 5 is a view corresponding to FIG. 2 according to the second embodiment.

FIG. 6 is a diagram corresponding to FIG. 2 according to a third embodiment.

FIG. 7 is a partially enlarged view of a display device according to the related art.

[Explanation of symbols]

2 ... Cold cathode fluorescent lamp (substantially linear luminous body), 3 ... Light guide plate, 31, 32 ... Inclined surface (first inclined surface), 3e ... Opposing surface (incident surface), 331-333, 341-343 ... V V-shaped groove portion (incident surface), 331a to 333a, 341a to 34
3a ... Inner wall surface (second inclined surface).

Claims (8)

[Claims] 1. A light guide plate (3), and a substantially linear light-emitting body (2) arranged along the back surface (3b) of the light guide plate (3) and allowing light to enter the light guide plate (3).
And a position (31b) farther from the substantially linear light-emitting body (2) in the light guide plate (3) from a position (31a, 32a) facing the substantially linear light-emitting body (2) in the light guide plate (3). , 32b) towards the light guide plate (3).
First inclined surfaces (31, 32) formed on the surface (3a) of the light guide plate (3) along the longitudinal direction of the substantially linear light-emitting body (2) so that the thickness of the light guide plate gradually increases. And the light emitted from the substantially linear light-emitting body (2) formed on the back surface (3b) of the light guide plate (3).
Incident surfaces (331 to 333, 341 to 34) to be incident on the inside
3, 3e, 38a), and the incident surfaces (331-333, 341-343, 3e,
38a) is a second inclined surface (331a to 333a, 341a to 3) that is inclined with respect to the back surface (3b) of the light guide plate (3) so as to substantially face the substantially linear light-emitting body (2).
43a, 38a), and the incident surfaces (331-333, 341-343, 3e,
38a) makes the light incident from the first inclined surface (31,
32), the first inclined surface (31, 32) and the second inclined surface (331a to 33) with respect to the back surface (3b) of the light guide plate (3) can be substantially totally reflected.
3a, 341a to 343a, 38a) is set to an inclination angle. 2. The incident surfaces (331 to 333, 341 to 341)
343, 3e, 38a) in the longitudinal direction of the substantially linear light-emitting body (2) formed in the vicinity of the substantially linear light-emitting body (2) on the back surface (3b) of the light guide plate (3). Parallel groove portions having a substantially V-shaped cross section (331 to 333, 341 to 341)
343), and the inner wall surface (331) that substantially opposes the substantially linear light-emitting body (2) in the groove portions (331 to 333, 341 to 343).
a-333a, 341a-343a), the second
Inclined surfaces (331a to 333a, 341a to 343a, 3
8a) is constituted, The light guide device of Claim 1 characterized by the above-mentioned. 3. On the back surface (3b) of the light guide plate (3), a plurality of the groove portions (331 to 333, 341 to 343) are formed in the vicinity of the substantially linear light emitting body (2). The light guide device according to claim 2. 4. The groove portions (331 to 333, 341 to 3)
43) The light guide device according to claim 2 or 3, wherein 43) is formed inside the back surface (3b) of the light guide plate (3) in the plate thickness direction. 5. The light guide device according to any one of claims 1 to 4, which is arranged along the surface (3a) of the light guide plate (3) and represents an instruction display unit such as a scale pattern. At least the incident surface (331 to 333, 341 to 343, 3) in the dial (1) having the pattern light transmitting portions (51 to 54) and the back surface (3b) of the light guide plate (3).
e, 38a) and a reflective layer (35) that is formed in a portion excluding the pattern light-transmitting portion (51-54) and is disposed along the substantially linear light-emitting body (2). In the pattern translucent part (51-54), at least the incident surface (331-333, 341-343, 3e, 38).
The reflection plate (10) that reflects the light of the substantially linear light-emitting body (2) is provided in a portion facing a), and the pattern translucent portion (51 to 5) is provided from the reflection plate (10).
4) so that the amount of light incident on the reflective layer (35) is substantially the same as the amount of light incident on the pattern translucent portions (51-54). A display device having a reflectance set. 6. The display device according to claim 5, wherein the reflector (10) is made of a gray-colored coloring material that satisfies the reflectance. 7. The light guide device according to claim 1, wherein the light guide device is arranged along the surface (3a) of the light guide plate (3) and represents an instruction display unit such as a scale pattern. At least the incident surface (331 to 333, 341 to 343, 3) in the dial (1) having the pattern light transmitting portions (51 to 54) and the back surface (3b) of the light guide plate (3).
e, 38a) and a reflective layer (35) that is formed in a portion excluding the pattern light-transmitting portion (51-54) and is disposed along the substantially linear light-emitting body (2). In the pattern translucent part (51-54), at least the incident surface (331-333, 341-343, 3e, 38).
The reflecting plate (10) for reflecting the light of the substantially linear light-emitting body (2) is provided in a portion facing a), and the substantially linear light-emitting body (2) and the dial plate (1) are provided. A light diffusing member (9) for diffusing light incident from the reflection plate (10) is disposed between the light diffusing members (9) and the pattern light transmitting portions (51 to 51).
54) so that the amount of light incident on the reflective layer (35) is substantially the same as the amount of light incident on the pattern translucent portions (51-54). A display device, wherein a reflectance and a light diffusion amount of the light diffusion member (9) are set. 8. The display according to claim 5, further comprising pointers (61 to 64) for giving an instruction on the pattern translucent portion (51 to 54). apparatus.