JP3204086B2 - Light guide device and display device using the same - 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 device and a display device using the same, and is particularly suitable for use as a display device for vehicles provided with hands.

[0002]

2. Description of the Related Art The present applicant has previously filed Japanese Patent Application No. Hei.
No. 4 is applied, and a display device as shown in FIG. 7 is proposed. FIG. 7 is a cross-sectional view of the display device 100 shown in FIG.
It is a partial view of a section. In this display device 100, for example, an acrylic resin light guide plate 3 is provided along the back surface 1b of the dial 1 provided with the 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 provided along.

[0003] 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 outside from the surface 3a.

[0004]

However, the inclined surface 32
Near 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 small, and the plate thickness of the light guide plate 3 is as thin as about 5 mm. Light incident angle 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 also occurs for the reflection surface 31.

Here, in order to perform total reflection 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. As a result, the cost of the light guide plate 3 increases. . The present invention has been made in view of the above problems, and in a light guide device in which light of a substantially linear luminous body is incident from the back surface of the light guide plate, without increasing the thickness of the light guide plate.
An object of the present invention is to reliably guide light of a substantially linear light-emitting body into a light guide plate.

[0006]

In order to achieve the above object, according to the present invention, the light guide plate (3) is provided.
Incident surface (331-333, 341-3) on the back surface (3b) of
43, 3e, 38a) are second inclined surfaces (331a to 333a, 341a to 341a) inclined with respect to the back surface (3b) of the light guide plate (3) so as to substantially face the substantially linear light emitter (2).
43a, 38a), and the incident surface (331-33).
3, 341 to 343, 3e, and 38a), the first light on the back surface (3b) of the light guide plate (3) so that the light can be substantially totally reflected on the first inclined surfaces (31, 32). The inclined surfaces (31, 32) and the second inclined surfaces (331a-331)
333a, 341a to 343a, 38a).

Accordingly, the incident surfaces (331-333, 341)
343, 3e, and 38a) can be substantially totally reflected on the first inclined surfaces (31, 32), and can prevent light from leaking from the first inclined surfaces (31, 32). The light of the luminous body (2) can be reliably guided into the light guide plate (3). In addition, the first inclined surfaces (31, 32) and the second inclined surfaces (331a to 333a, 341a to 343).
a, 38a), the first inclined surface (31, 32)
Can be adjusted, the thickness of the light guide plate (3) can be reduced as compared with the case where the incident angle is adjusted only by the first inclined surfaces (31, 32), and the cost can be reduced. Can be planned.

Further, the second inclined surfaces (331a to 333a,
341a to 343a, 38a) are substantially opposed to the substantially linear luminous body (2), so that more light emitted from the substantially linear luminous body (2) can be incident on the light guide plate (3). Also,
Since the substantially linear light-emitting body (2) is used as a light source, light incident on the light guide plate (3) can be made uniform as compared with a point light source.
Light can be uniformly guided over the entire surface of the light guide plate (3).

Further, according to the third aspect of the present invention, on the back surface (3b) of the light guide plate (3), near the substantially linear luminous body (2), parallel to the longitudinal direction of the substantially linear luminous body (2). In addition, groove portions (331-333, 341-3) having a substantially V-shaped cross section are used.
43) are formed. Therefore, the plurality of grooves (33
1 to 333, 341 to 343) and the inner wall surfaces (331a to 333a, 341) facing the substantially linear light-emitting body (2).
a to 343a) can be changed according to the inclination angles of the first inclined surfaces (31, 32),
Light leakage from the first inclined surfaces (31, 32) can be more effectively prevented.

In particular, according to the fourth aspect of the present invention, the grooves (331 to 333, 341 to 343) are formed in the light guide plate (3).
Since it is formed on the inner side in the thickness direction of the back surface (3b), the light guide plate (3) becomes 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, the printing can be performed at once on the entire back surface (3b) of the light guide plate (3), and the printing process is facilitated.

According to the fifth aspect of the present invention, on the back surface (3b) of the light guide plate (3), at least a portion excluding the incident surfaces (331-333, 341-343, 3e, 38a) has a reflective layer (3). 35), and a reflector (10) is provided along the substantially linear light emitter (2). Therefore,
Using the above-described light guide device in which more light from the substantially linear light-emitting body (2) is guided into the light guide plate (3), the light in the light guide plate (3) is reflected by the reflection plate (10) and reflected. In the layer (35), the pattern light-transmitting portions (51-54) can be illuminated by reflecting the light to the pattern light-transmitting portions (51-54). It can be improved and can be easily recognized by a viewer.

The amount of light incident on the pattern light transmitting portions (51 to 54) from the reflecting plate (10) varies from the reflecting layer (35) on the back surface (3b) of the light guide plate (3). (5
Since 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 to 54).
32) can be prevented from being brighter than the pattern light-transmitting portions (51 to 54) other than this portion,
The entire surface of the pattern light transmitting portions (51 to 54) can be uniformly illuminated.

Further, light from the substantially linear light emitter (2) is guided by the light guide plate (3), and the light can irradiate the entire pattern display portion (51-54). For this reason, even if the shape and position of the pattern display sections (51 to 54) are changed, it is not necessary to change the position and shape of the substantially linear light emitter (2). Furthermore, 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 as compared with the point light source.
4) can be more uniformly irradiated.

In particular, in the invention according to claim 6, since the color of the reflecting plate (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 on the reflector (10) can be suppressed.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. (First Embodiment) A first embodiment is shown in FIGS.
As shown in the figure, the hands 61, 62, 63, 64 (hereinafter, 6)
1 to 64) are applied to a display device 100 for a vehicle provided with the present invention. The display device 100 is attached to an instrument panel in front of a driver's seat in a vehicle cabin. 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 substantially rectangular plate member in which a black printed layer 12 is formed on the surface of a transparent plate member 11. Then, the pattern light transmitting portions 51 to 54 are formed on the dial 1 by punching out the black print layer 12 corresponding to the pattern light transmitting portions 51 to 54. The center of the dial 1 faces substantially the center of the driver's seat. Pattern translucent part 5
1 is an arc-shaped rotation speed scale pattern representing a scale of the engine speed and a unit of the engine speed (× 1000RP).
M).
The pattern translucent section 52 includes an arc-shaped vehicle speed scale pattern indicating a scale of the vehicle speed and a vehicle speed unit pattern indicating a unit (km / h) of the vehicle speed.

The pattern translucent section 53 is composed of an arc-shaped water temperature scale pattern indicating a scale of water temperature and a water temperature mark. The pattern translucent section 54 is configured by an arc-shaped fuel scale pattern indicating a scale of the fuel amount and a fuel mark. The instruction display unit in the claims refers to 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, for example, a transparent acrylic resin. The light guide plate 3 is mounted along the back surface 1 b of the dial 1. On the back surface 3b of the light guide plate 3, a cold cathode fluorescent lamp (substantially linear light emitter) 2 having a length substantially equal to the length of the light guide plate 3 in the longitudinal direction is mounted. The cold cathode fluorescent lamp 2 is disposed on the rear surface 3b of the light guide plate 3 slightly closer to the upper end 3c than the center in the longitudinal direction of the light guide plate 3. The cold cathode fluorescent lamp 2 emits light when the ignition switch of the vehicle is turned on.

The front surface 3a of the light guide plate 3 has inclined surfaces (first inclined surfaces) 31, 3 along the longitudinal direction of the cold cathode fluorescent lamp 2.
2 are formed. The inclined surfaces 31 and 32 extend from one ends 31 a and 32 a (positions facing the cold cathode fluorescent lamp 2 in the light guide plate 3) to other ends 31 b and 32 b (positions away from the cold cathode fluorescent lamp 2 in the light guide plate 3). The light guide plate 3 is inclined such that the thickness of the light guide plate 3 gradually increases as it moves. The inclined surfaces 31 and 32 are
Are formed line-symmetrically with respect to the one ends 31a and 32a of the first.

On the back surface 3b of the light guide plate 3, a notch 33 having a sawtooth cross section is provided at a position farther from the cold cathode fluorescent lamp 2 than an opposing surface (incident surface) 3e substantially facing the cold cathode fluorescent lamp 2. , 34 are formed along the longitudinal direction of the cold cathode fluorescent lamp 2. As shown in FIG. 3, the notches 33 and 34 have a plurality of, for example, three V
It is formed from letter-shaped grooves (incident surfaces) 331-333, 341-343. The notches 33 and 34 are provided on the inclined surface 3.
1, 32 are formed line-symmetrically with respect to one end 31a, 32a.

It is to be noted that a notch 33 is provided on the back surface 3b of the light guide plate 3.
In a state where the light guide plate 3 is not formed, the inclined surfaces 31 and 32 are formed on the surface 3a of the light guide plate 3 at portions where the light incident into the light guide plate 3 leaks. Here, the V-shaped groove 3
31 to 333, 341 to 343, inner wall surfaces 331a to 333a and 341a facing the cold cathode fluorescent lamp 2;
To 343a are second inclined surfaces referred to in the claims.

The V-shaped grooves 331 to 333, 34
The inclined surfaces 31 and 32 with respect to the back surface 3b of the light guide plate 3 so that the light incident from the surfaces 1 to 343 and the facing surface 3e can be substantially totally reflected on the inclined surfaces 31 and 32.
The inclination angles of the inner wall surfaces 331a to 333a and 341a to 343a are set. In the present embodiment, instead of indicating the inclination angles of the inclined surfaces 31, 32 and the inner wall surfaces 331a to 333a, 341a to 343a with respect to the back surface 3b of the light guide plate 3, the inclined surfaces 31, 32 and the inner wall surface 38a are shown.
Are shown below.

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

Specifically, in this embodiment, the thickness T of the light guide plate 3 is 5 mm, and the height D 1 of the inclined surfaces 31 and 32 is 4.5 m.
m. The width W1 of the curved portion 311 is 5.91 mm, the height D2 is 3.58 mm, and the cross-sectional shape of the curved 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 cross-sectional shape of the flat portion 312 is linear.

The depth D4 of the V-shaped groove 341 is set at 0.1.
97 mm, inner wall surface 341a with respect to back surface 3b of light guide plate 3
Angle of inclination (hereinafter referred to as 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 °, and the V-shaped groove 34
3, the depth D6 is 0.91 mm, and the inclination angle θ3 of the inner wall surface 343a is 30 °. Then, V-shaped grooves 331 to 3
33 is configured similarly to the V-shaped grooves 341-343.

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 in portions other than the portions ３３333 and 341１〜３343. The reflection layer 35 is formed of the light guide plate 3.
The light guided inside is transmitted through the pattern light transmitting portions 51 to 5 of the dial 1.
It plays the role of reflecting light to the fourth. As shown in FIG. 2, the cover member 4 is made of a light-shielding material such as white-colored polypropylene or the like.
Is covered. This cover member 4 is substantially bowl-shaped,
The V-shaped grooves 331 to 333 of the light guide plate 3 are
The through holes 41 are formed such that the 341 to 343 and the facing surface 3e are reliably exposed. Thereby, on the back surface 3b of the light guide plate 3, V-shaped grooves 331 to 333, 3
The light of the cold cathode fluorescent lamp 2 is incident only from 41 to 343 and the facing surface 3e. And the through hole 41
An annular projection 42 is formed on the outer peripheral portion of the outer peripheral portion to project substantially perpendicularly from the outer peripheral portion.

The cold cathode fluorescent lamp 2 is held by the reflector 10 mounted on the inner periphery of the annular projection 42 of the cover member 4. Here, the amount of light reflected to the pattern light transmitting portions 51 to 54 by the reflection plate 10 is the amount of light reflected to the pattern light transmitting portions 51 to 54 of the dial 1 by the reflection layer 35 on the back surface 3 b of the light guide plate 3. So that it is almost the same as
The reflectance of the reflector 10 is set. The reflection plate 1
By adjusting the brightness of 0, the reflectance is adjusted. In the present embodiment, the reflection plate 10 is formed of a gray material that satisfies the reflectance.

The reflecting plate 10 includes a reflecting portion 101 having a substantially arc-shaped cross section, and mounting portions 102 formed at the upper and lower ends of the reflecting portion 101 in the longitudinal direction. The mounting portion 102 is a cover member. Four annular projections 42
It is installed inside. As shown in FIG. 1, the display device 100 has hands 61 to 64 for indicating a vehicle speed, a rotation speed, a water temperature, and a fuel amount, and these hands 61 to 64.
And each drive device (not shown) for driving the drive.
Each of the hands 61 to 64 is a pattern light transmitting part 51 to 51, respectively.
54, the hands 61 to 6
Reference numeral 4 denotes a cold cathode fluorescent lamp.

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

According to the display device 100 having the above configuration, FIG.
In this case, when the cold cathode fluorescent lamp 2 emits light, the light emitted from the cold cathode fluorescent lamp 2 is transmitted to the opposing surface 3 e of the back surface 3 b of the light guide plate 3 and the inner wall surfaces 331 a to 3 of the cut portions 33 and 34.
33a, 341a to 343a, the incident light is substantially totally reflected on the reflection surfaces 31, 32 of the light guide plate 3,
The upper end 3c (see FIG. 2) side and lower end 3d of the light guide plate 3
(See FIG. 2). Further, this light is reflected again toward the center of the light guide plate 3 at the upper end 3c and the lower end 3d.

As described above, since the light once entering the light guide plate 3 can be prevented from leaking to the outside, the light guide plate 3
The light emitted from the cold cathode fluorescent lamp 2 is surely guided inside,
This light is reflected on the reflection layer 35 formed on the back surface 3 b of the light guide plate 3.
As a result, the pattern light transmitting portions 51 to 54 of the dial 1 can be efficiently provided.
Is reflected to At the same time, the back surface 2b of the cold cathode fluorescent lamp 2
Is incident on the reflector 10, and most of the incident light is reflected on the back surface 3 of the light guide plate 3 by the reflector 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 light from the reflecting layer 35 formed on the back surface 3 b 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, the entire surface of the pattern light transmitting portions 51 to 54 can be uniformly illuminated.

The inner wall surfaces 331a to 333a and 341a to 343 are provided in accordance with the inclination angles of the inclined surfaces 31 and 32.
Since the respective inclination angles of “a” can be changed, light leakage from the inclined surfaces 31 and 32 can be more effectively prevented. Also, the inner wall surfaces 331a to 333 of the notches 33, 34
Since a and 341a to 343a are substantially opposed to the cold cathode fluorescent lamp 2, more light emitted from the cold cathode fluorescent lamp 2 can enter the light guide plate 3.

Since the reflection plate 10 is gray and achromatic, the color tone of the light emitted from the cold cathode fluorescent lamp 2 does not change. The light emitted from the cold cathode fluorescent lamp 2 is guided by the light guide plate 3, and the light can irradiate the entire pattern light transmitting portions 51 to 54. For this reason, even if the shapes and positions of the pattern translucent portions 51 to 54 are changed, it is not necessary to change the positions and shapes of the cold cathode fluorescent lamps 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 uniform as compared with the point light source, and thus the pattern light transmitting portions 51 to 54 can be illuminated more uniformly. Can be. (Second Embodiment) In this 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 small 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 W 3 of the semicircular groove 38 is larger than the diameter of the cold cathode fluorescent lamp 2, and the inner wall surface 38 a of the semicircular groove 38 receives light emitted from the cold cathode fluorescent lamp 2. The second inclined surface is an incident surface on which 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 of the light incident from the inner wall surface 38a of the semicircular groove portion 38 can be totally reflected on the inclined surfaces 31, 32 of the light guide plate 3. Is set. In the present embodiment, the light guide plate 3
Inclined surfaces 31, 32 and inner wall surface 38 with respect to the rear surface 3b
Instead of indicating the inclination angle of a, the dimensions of the inclined surfaces 31, 32 and the inner wall surface 38a, which will be 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, 32 is 4.3 mm, and the widths W4, W5 of the inclined surfaces 31, 32 are 6.7 mm. .
Also, the protrusion height H1 of the protrusions 36 and 37 is 2.5 mm,
The width W3 of the semicircular groove 38 is 5 mm, and the depth D7 of the semicircular groove 38 is 2.5 mm. In addition, the inclined surfaces 31 and 3
The cross-sectional shape of No. 2 is a part of an ellipse having a major axis length of 36.7 mm and a minor axis length of 16.1 mm.

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

According to the above configuration, the light emitted from the cold cathode fluorescent lamp 2 is incident on the inner wall surface 38a of the semicircular groove 38 substantially perpendicularly.
8a, the surface 3 of the light guide plate 3 is hardly refracted.
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 than in the first embodiment.

(Third Embodiment) In this embodiment, as shown in FIG. 6, the reflecting plate 10 in the second embodiment is used.
Are formed integrally with a cover member 4 made of a white resin material.
A light diffusing plate (light diffusing member) having a length substantially equal to the length of the cold cathode fluorescent lamp 2 in the longitudinal direction between the first and second dials 32 and the dial 1.
9 are arranged. The width V of the light diffusing plate 9 is substantially equal to the width W3 of the semicircular groove 38 of the light guide plate 3, and the light diffusing plate 9 is formed of a milky white material in which glass beads are mixed into a transparent material. Plays a role in diffusing incident light. The light diffusing plate 9 is fixedly adhered to the dial 1.

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 different. The light diffusion amount of the light diffusion plate 9 is adjusted so as to be substantially the same. Specifically, the amount of light diffusion can be increased by increasing the amount of the glass beads mixed. In the present embodiment, since the reflector 10 is made of a white material having a high reflectance, the amount of light reflected by the reflector 10 is larger than that in the first embodiment. By diffusing the light by 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 notches 33, 34 are formed by three V-shaped grooves 331-33.
3, 341 to 334, the present invention is not limited to this, and the number of V-shaped grooves may be appropriately changed. For example, the number of V-shaped grooves may be two or less, or four or more.

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

Although both of the notches 33 and 34 are formed by the three V-shaped grooves 331 to 333 and 341 to 334, the V-shaped grooves 331 to 333 of the notch 34 are formed.
May be larger than the number of V-shaped grooves 341 to 334 of the notch 33. As a result, the light from the cold cathode fluorescent lamp 2 is transmitted to the light guide plate 3 by an amount corresponding to the increase in the number of V-shaped grooves.
More light can be guided to the lower end 3 d side of the light guide plate 3.

Here, the cold cathode fluorescent lamp 2 comprises a light guide plate 3
Is arranged closer to the upper end portion 1c than the center portion in the longitudinal direction of the light guide plate 3. Therefore, by guiding more light to the lower end portion 3d side of the light guide plate 3, light is uniformly guided over the entire light guide plate 3. Can light. In the first and second embodiments, the reflection plate 10 is made of a gray, that is, an achromatic resin material. However, the present invention is not limited to this. You may comprise with a coloring material.

In the first to third embodiments, the light is efficiently reflected on the dial 1 by the reflection layer 35 provided on the back surface 3b of the light guide plate 3. A grain may be provided, and the grain may efficiently reflect light to the dial 1. In the second and third embodiments, the inner wall surface 38a is formed on the back surface 3b of the light guide plate 3.
Although the printing layer 35 is provided on the portion other than the inner wall surface 38a and the reflection plate 10 is disposed on the portion facing the inner wall surface 38a, printing is performed on the back surface 3b of the light guide plate 3 except for the inner wall surface 38a and the protruding portions 36 and 37. The layer 35 may be provided, and the reflection plate 10 may be disposed at a portion facing the inner wall surface 38a and the protrusions 36 and 37. Accordingly, the portion where the print layer 35 is provided becomes flat, and it is not necessary to print on the inclined portions such as the protruding portions 36 and 37 of the light guide plate 3, so that the printing process of the print layer 34 is simplified.

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. Even when the light diffusing plate 9 is applied to the display device 100 in which the reflecting plate 10 is made of a gray-based material having a slightly lower reflectance than the white-based material. Good.

In the third embodiment, the light from the reflecting plate 10 is diffused by the light diffusing plate 9; The light may be diffused by a shade.

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along 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 a light guide plate for explaining dimensions of the light guide plate.

FIG. 5 is a diagram corresponding to FIG. 2 according to a 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 opposed surface (incident surface), 331-333, 341-343 V V-shaped grooves (incident surface), 331a to 333a, 341a to 34
3a: inner wall surface (second inclined surface).

Claims (8)

(57) [Claims] 1. A light guide plate (3), and a substantially linear illuminator (2) arranged along a back surface (3b) of the light guide plate (3) and for entering light into the light guide plate (3).
A position (31b) in the light guide plate (3) that is farther from the substantially linear light emitter (2) from a position (31a, 32a) facing the substantially linear light emitter (2); , 32b), the light guide plate (3)
The 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 emitter (2) so that the thickness of the light guide plate (3) gradually increases. The light guide plate (3) is formed on the back surface (3b) of the light guide plate (3) and emits light emitted by the substantially linear light emitter (2).
Incident surfaces (331-333, 341-34)
3, 3e, 38a), and the incident surfaces (331-333, 341-343, 3e,
38a) are second inclined surfaces (331a to 333a, 341a to 331) inclined with respect to the back surface (3b) of the light guide plate (3) so as to substantially face the substantially linear light emitter (2).
43a, 38a), and the incident surfaces (331-333, 341-343, 3e,
38a) is incident on the first inclined surface (31,
32), the first inclined surfaces (31, 32) and the second inclined surfaces (331a to 33) with respect to the back surface (3b) of the light guide plate (3) so that substantially total reflection is possible.
3a, 341a to 343a, 38a), wherein the inclination angle is set. 2. The light incident surface (331-333, 341-341).
343, 3e, 38a) are formed on the back surface (3b) of the light guide plate (3) in the longitudinal direction of the substantially linear light emitter (2) formed near the substantially linear light emitter (2). Parallel, substantially V-shaped grooves (331-333, 341-341)
343), and an inner wall surface (331) substantially opposed to the substantially linear luminous body (2) in the groove portions (331-333, 341-343).
a to 333a and 341a to 343a).
Inclined surfaces (331a to 333a, 341a to 343a, 3
8. The light guide device according to claim 1, wherein 8a) is configured. 3. A plurality of the grooves (331-333, 341-343) are formed in the back surface (3b) of the light guide plate (3) in the vicinity of the substantially linear light emitter (2). The light guide device according to claim 2, wherein: 4. The groove (331-333, 341-3)
The light guide device according to claim 2, wherein the light guide plate is formed inside the back surface of the light guide plate in the thickness direction. 5. 5. A 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. The dial (1) having the pattern light transmitting portions (51 to 54) and the back surface (3b) of the light guide plate (3) have at least the incident surfaces (331 to 333, 341 to 343,
e, 38a), a reflection layer (35) that reflects light to the pattern light-transmitting portions (51 to 54), and a reflection layer (35) that is disposed along the substantially linear light emitter (2); In the pattern light transmitting portions (51 to 54), at least the incident surfaces (331 to 333, 341 to 343, 3e, 38)
a) a reflection plate (10) for reflecting the light of the substantially linear luminous body (2) on a portion opposed to (a), wherein the pattern transmission portion (51-5) 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) from the reflective layer (35). A display device, wherein a reflectance is set. 6. The display device according to claim 5, wherein the reflector (10) is made of a gray coloring material satisfying the reflectance. 7. A 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. The dial (1) having the pattern light transmitting portions (51 to 54) and the back surface (3b) of the light guide plate (3) have at least the incident surfaces (331 to 333, 341 to 343,
e, 38a), a reflection layer (35) that reflects light to the pattern light-transmitting portions (51 to 54), and a reflection layer (35) that is disposed along the substantially linear light emitter (2); In the pattern light transmitting portions (51 to 54), at least the incident surfaces (331 to 333, 341 to 343, 3e, 38)
A reflector (10) for reflecting light of the substantially linear luminous body (2) is provided on a portion facing a), and the substantially linear luminous body (2) and the dial (1) are provided. A light diffusion member (9) for diffusing light incident from the reflection plate (10) is disposed between the light diffusion member (9) and the pattern light transmission portion (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) from the reflective layer (35). 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 a pointer (61-64) for giving an instruction on the pattern light transmitting portion (51-54). apparatus.