JP2004243828A - Display device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device for a vehicle preventing a change in the positional relationship of an optical sheet and a light guide plate and preventing partial unevenness in light emission luminance of a display member from occurring. <P>SOLUTION: A texture surface 53 composed of a lot of fine irregularities is formed on a surface on a side of the optical sheet 6 of the light guide plate 5 and the optical sheet 6 is brought into contact with the texture surface 53. Thereby, the optical sheet 6 is supported by a lot of protrusions 53b in a point contact state and gaps are always formed between the optical sheet and the light guide plate 5. Therefore, the gaps between the optical sheet 6 and the light guide plate 5 can always prevent the optical sheet 6 from bending and planarly coming in contact with the light guide plate 5 in the using process of a combination meter 1 not like in a conventional display device for a vehicle while a light emission luminance increasing effect in a liquid crystal panel 3 by these gaps is being maintained. Therefore, the combination meter 1 capable of preventing the unevenness of the light emission luminance in the liquid crystal panel 3 can be realized. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a display device for a vehicle, and is suitable for use in, for example, an automobile.
[0002]
[Prior art]
In a conventional vehicle display device, a light source is disposed on the back surface side of a flat display member, and a light guide plate that guides light from the light source and emits the light toward the back surface of the display member is also provided on the back surface side of the display member. Are placed. Further, an optical sheet is disposed between the display member and the light guide plate. The optical sheet refracts the light from the light source emitted from the light guide plate so as to approach the normal direction of the display member, in other words, the light emitted from the light guide plate is orthogonal to the display member, that is, by the driver. The light is refracted so as to approach the viewing direction. This makes it possible to increase the amount of transmitted light for transmitting and illuminating the display member (for example, see Patent Document 1).
[0003]
In this case, by providing a gap between the light guide plate and the optical sheet, the amount of transmitted light for transmitting and illuminating the display member can be further increased, and the light emission luminance of the display member can be increased. This is because the light traveling from the light guide plate toward the optical sheet is refracted so as to approach the normal direction of the display member when exiting from the light guide plate into the gap, that is, into the air.
[0004]
Therefore, in the vehicular display device, the optical sheet is disposed at a predetermined distance from the light guide plate.
[0005]
[Patent Document 1]
Japanese Patent No. 3246359 gazette
[Problems to be solved by the invention]
However, in the case of the above-described vehicle display device, the optical sheet bends during its use, the gap between the light guide plate and the optical sheet becomes uneven, and the optical sheet partially contacts the light guide plate. You may come to do. In this case, the brightness of the light traveling from the optical sheet to the display member is not uniform, that is, the illuminance at the portion where the optical sheet is in contact with the light guide plate is reduced. Therefore, there is a problem that a partial unevenness is generated in the light emission luminance of the display member, and the appearance of the vehicle display device is deteriorated.
[0007]
The present invention has been made in view of the above problems, and has as its object to prevent the change in the positional relationship between the optical sheet and the light guide plate by devising the configuration of the display device for a vehicle, and to emit light from the display member. An object of the present invention is to provide a display device for a vehicle in which partial unevenness does not occur in luminance.
[0008]
[Means for Solving the Problems]
The present invention employs the following technical means to achieve the above object.
[0009]
The display device for a vehicle according to claim 1 of the present invention is configured such that a flat display member, a light source disposed on the back side of the display member, and a light source disposed on the back side of the display member guide light from the light source. A light guide plate that emits light toward the back of the display member, and an optical sheet that is disposed between the display member and the light guide plate and refracts light from a light source emitted from the light guide plate so as to approach the normal direction of the display member. And a textured surface is formed on a side surface of the optical sheet of the light guide plate, and the optical sheet is installed in contact with the textured surface.
[0010]
Thus, in the process of using the display device for a vehicle, the positional relationship between the optical sheet and the light guide plate can be maintained without changing, so that the light emission of the display member due to the bending of the optical sheet in the conventional display device for a vehicle. Since unevenness in luminance can be eliminated, it is possible to provide a vehicle display device in which unevenness in light emission luminance of the display member does not occur.
[0011]
Here, the textured surface is a surface composed of a large number of fine irregularities, and the optical sheet is in contact with the tip of the convex portion of the textured surface. That is, they are in point contact. On the other hand, air is filled in the concave portion of the grain surface.
[0012]
Therefore, when the optical sheet is brought into contact with the embossed surface of the light guide plate, the contact area between the two is extremely small, and between the optical sheet and the light guide plate as in the case of the conventional vehicle display device. Has an air layer formed. For this reason, in the vehicle display device according to the first aspect, similarly to the case of the conventional vehicle display device, it is possible to further increase the amount of transmitted light for transmitting and illuminating the display member to increase the light emission luminance of the display member. it can.
[0013]
Further, since the unevenness of the grain surface is formed uniformly, the contact points between the optical sheet and the light guide plate are also uniformly distributed over the entire area of the optical sheet. Therefore, the light emission luminance of the optical sheet, that is, the light emission luminance of the display member can be made uniform.
[0014]
The display device for a vehicle according to claim 2 is configured such that the display member is a liquid crystal panel. As a result, it is possible to realize a vehicle display device with excellent appearance by making the light emission luminance of the liquid crystal panel uniform.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a case where the vehicle display device according to the present invention is applied to a combination meter of an automobile will be described with reference to the drawings.
[0016]
FIG. 1 is a cross-sectional view of a combination meter 1 according to an embodiment of the present invention, and is a cross-sectional view taken along a line II in FIG.
[0017]
FIG. 2 is a partial front view of the combination meter 1 according to one embodiment of the present invention.
[0018]
FIG. 3 is a schematic diagram illustrating an electric circuit configuration of the combination meter 1 according to one embodiment of the present invention.
[0019]
FIG. 4 is a partially enlarged cross-sectional view of the combination meter 1 according to one embodiment of the present invention, and is an enlarged view of a part IV in FIG.
[0020]
The combination meter 1 is disposed at a position visible to a driver in front of a driver's seat of a vehicle, and includes a display panel 2 for displaying various information and visually recognizing the driver. In FIG. 2, the up-down direction is the up-down direction of the vehicle, and the upper side is the upper side of the vehicle.
[0021]
The display panel 2 is formed of a flat plate made of a translucent material, for example, a colorless and transparent polycarbonate. A liquid crystal panel 3 is disposed below the display panel 2.
[0022]
In the present embodiment, as shown in FIG. 2, the liquid crystal panel 3 serving as a display member includes an odometer (displaying the total mileage of the vehicle) 31 and a trip meter (from the time when the driver performs a predetermined operation). Is displayed) 32 is formed.
[0023]
On the back side of the liquid crystal panel 3 (the side opposite to the viewing side, the lower side in FIG. 1), a light emitting diode 4 which is a light source for transmitting and illuminating the liquid crystal panel 3 and a back surface 33 of the liquid crystal panel 3 which guides light from the light emitting diode A light guide plate 5 that emits light toward is arranged.
[0024]
The light guide plate 5 is formed of a translucent material, for example, a colorless and transparent polycarbonate resin. As shown in FIG. 1, the light guide plate 5 has an incident surface 51 on which light from the light emitting diode 4 is incident and an emission surface 52 on which light is emitted toward the liquid crystal panel 3. The emission surface 52 is formed in substantially the same shape as the rear surface of the liquid crystal panel 3 so that the entire surface of the liquid crystal panel 3 can be transmitted and illuminated. In addition, as shown in FIG. 4, a textured surface 53 composed of a large number of fine irregularities is formed on the emission surface 52. The textured surface 53 is simultaneously formed by a molding die when the light guide plate 5 is molded with resin. On the back surface 54 of the light guide plate 5 opposite to the light exit surface 52, the light from the light emitting diode 4 incident on the light guide plate 5 from the incident surface 51 is diffused and reflected toward the light exit surface 52. A diffuse reflection layer 55 is formed. In the present embodiment, white paint is applied as the diffuse reflection layer 55. The light from the light-emitting diode 4 that has entered the light guide plate 5 from the incident surface 51 travels in the light guide 5 as shown by an arrow in FIG. 1 and is reflected by the diffuse reflection layer 55 toward the emission surface 52. .
[0025]
In addition, between the light exit surface 52 of the light guide plate 5 and the back surface 33 of the liquid crystal panel 3, an optical element that refracts light from the light exit surface 52 so as to approach the normal direction of the liquid crystal panel 3 (vertical direction in FIG. 1). The seat 6 is arranged. As shown in FIG. 1, the optical sheet 6 is disposed so as to be in contact with the emission surface 52, that is, the embossed surface 53.
[0026]
As the light emitting diode 4, for example, a white light emitting diode is used. As shown in FIG. 1, the light emitting diode 4 is mounted on a printed circuit board 7 which is also arranged on the back surface of the liquid crystal panel 3 and forms an electric circuit section of the combination meter 1. The above-mentioned liquid crystal panel 3 is also connected to the printed circuit board 7 by a lead wire (not shown) or the like.
[0027]
As shown in FIG. 1, a control device 8 for controlling the display contents of the odometer 31 and the trip meter 32 on the liquid crystal panel 3 is mounted on the printed circuit board 7. The control device 8 is configured by a microcomputer or the like, and controls display values of the meters 31 and 32 according to an external electric signal, that is, a traveling distance detection signal. Further, it controls the turning on and off of the light emitting diode 4.
[0028]
Next, an electric circuit configuration and operation of the combination meter 1 according to the embodiment of the present invention described above will be described with reference to FIG.
[0029]
FIG. 3 is a schematic diagram illustrating an electric circuit configuration of the combination meter 1 according to one embodiment of the present invention.
[0030]
As shown in FIG. 3, the control device 8 is constantly supplied with power from the battery 10. Further, an ignition switch 9 is connected so that ON / OFF of the ignition switch 9 can be detected. Further, a running distance detection sensor 11 is connected to the control device 8.
[0031]
When the ignition switch 9 is turned on by the driver, the control device 8 detects this and starts operating, the light emitting diode 4 is turned on, and the odometer 31 and the trip meter 32 of the liquid crystal panel 3 are illuminated and displayed. When the vehicle starts running, the numerical values displayed on the odometer 31 and the trip meter 32 are updated by the control device 8 based on the detection signal from the running distance detection sensor 11.
[0032]
Next, the arrangement configuration of the light guide plate 5 and the optical sheet 6, which are features of the combination meter 1 according to one embodiment of the present invention, and the effects thereof will be described.
[0033]
In the combination meter 1 according to one embodiment of the present invention, as shown in FIG. 4, the optical sheet 6 is fixed in contact with the grained surface 53 of the light guide plate 5. As shown in FIG. 4, the optical sheet 6 is provided with a large number of grooves having a triangular cross section. When the light incident on the optical sheet 6 from the light guide 5 is emitted from the slope 61, the liquid crystal panel The light is refracted so as to approach the normal direction of FIG. 3, that is, the vertical direction in FIG.
[0034]
As shown in the enlarged cross-sectional view of FIG. 4, the textured surface 53 of the light guide plate 5 includes a concave portion 53a and a convex portion 53b, and the optical sheet 6 has a tip of the convex portion 53b of the grained surface 53. At point contact with the convex portion 53b. That is, the contact area between the projection 53b and the optical sheet 6 is very small. For this reason, the total area of the projections 53 b, that is, the contact area with the light guide plate 5 in the entire optical sheet 6 is extremely small as compared with the entire area of the optical sheet 6. This means that, in other words, in a state where the optical sheet 6 is attached to the light guide plate 5, an air layer is still formed between the two, and the area thereof is considerably close to the area of the optical sheet 6. I have.
[0035]
Therefore, most of the light that is reflected toward the liquid crystal panel 3 by the diffuse reflection layer 55 of the light guide 5 and enters the optical sheet 6 from the emission surface 52 passes from the concave portion 53 b of the embossed surface 53 via the air layer to the optical layer. It will be incident on the sheet.
[0036]
Further, since the optical sheet 6 is supported by being in contact with the many convex portions 53b, even when the optical sheet 6 is softened due to, for example, an increase in environmental temperature, the amount of bending of the optical sheet 6, that is, the adjacent convex portion Between the portions 53b, the amount of displacement of the optical sheet 6 in the vertical direction in FIG. 4 is extremely small as compared with the depth (dimension D in FIG. 4) of the concave portion 53a, and the optical sheet 6 contacts the concave portion 53a. I will not.
[0037]
Thereby, the unevenness of the light emission luminance of the display member (for example, the liquid crystal panel) due to the bending of the optical sheet in the conventional vehicle display device can be eliminated. 1 can be realized.
[0038]
Further, according to the above-described configuration, an air layer is formed between the light guide plate 5 and the optical sheet 6 and the area thereof is substantially equal to the area of the optical sheet 6. In the case, the effect of the gap between the light guide plate and the optical sheet, that is, when the light emitted from the light guide plate 6 is emitted into the air from the emission surface 52, that is, the concave portion 53a, into the normal direction of the liquid crystal panel 3, that is, FIG. In this case, the light is refracted so as to be closer to the driver's viewing direction, so that the amount of transmitted light for transmitting and illuminating the liquid crystal panel 3 can be further increased, and the effect of increasing the light emission luminance of the liquid crystal panel 3 can be obtained.
[0039]
Further, since the concave portions 53a and the convex portions 53b of the textured surface 53 are uniformly arranged according to a predetermined rule, the contact points between the optical sheet 6 and the light guide plate 5 are also uniformly distributed over the entire area of the optical sheet 6. are doing. Therefore, the light emission luminance of the optical sheet 6, that is, the light emission luminance of the liquid crystal panel 3 can be made uniform.
[0040]
In the combination meter 1 according to the embodiment of the present invention described above, the odometer 31 and the trip meter 32 are displayed on the liquid crystal panel 3, but other display contents may be used. For example, a clock, a temperature outside the vehicle, and the like may be displayed.
[0041]
Further, in the combination meter 1 according to the embodiment of the present invention described above, the liquid crystal panel 3 is used as a display member. However, the present invention is not limited to the liquid crystal panel 3, and the display member is formed on the display panel 2. The display design may be a display design (not shown), and the display design may be illuminated with transmitted light.
[0042]
In addition, in the combination meter 1 according to the embodiment of the present invention, a white paint is applied as the diffuse reflection layer 55 provided on the back surface 54 of the light guide 5, but it is not necessary to limit to a white paint. Etc., or a textured surface or the like.
[0043]
Further, in the combination meter 1 according to the embodiment of the present invention, the light emission color of the light emitting diode 4 is white, but the color is not limited to white and another color may be used.
[0044]
Further, in the combination meter 1 according to the embodiment of the present invention, the light emitting diode 4 is used as a light source.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a combination meter 1 according to an embodiment of the present invention, which is a cross-sectional view taken along a line II in FIG.
FIG. 2 is a partial front view of the combination meter 1 according to one embodiment of the present invention.
FIG. 3 is a schematic diagram illustrating an electric circuit configuration of the combination meter 1 according to one embodiment of the present invention.
FIG. 4 is a partially enlarged cross-sectional view of the combination meter 1 according to the embodiment of the present invention, and is an enlarged view of an IV section in FIG.
[Explanation of symbols]
1 Combination meter (vehicle display device)
2 Dial 3 Liquid crystal panel (display member)
31 Odometer 32 Trip meter 33 Back 4 Light emitting diode (light source)
Reference Signs List 5 light guide plate 51 incident surface 52 emission surface 53 embossed surface 54 back surface 55 diffuse reflection layer 6 optical sheet 7 printed circuit board 8 control device 9 ignition switch 10 battery 11 travel distance detection sensor D depth dimension

Claims (2)

A flat display member,
A light source arranged on the back side of the display member,
A light guide plate disposed on the back side of the display member to guide light from the light source and emit the light toward the back side of the display member;
An optical sheet disposed between the display member and the light guide plate to refract light from the light source emitted from the light guide plate so as to approach a normal direction of the display member. hand,
A display device for a vehicle, wherein a textured surface is formed on a side surface of the optical sheet of the light guide plate, and the optical sheet is installed in contact with the textured surface. The vehicle lighting device according to claim 1, wherein the display member is a liquid crystal panel.

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