JPH0453671Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a liquid crystal display device installed as a speedometer in a vehicle such as an automobile, and specifically relates to the structure of a lighting device.

<Prior art> A conventional liquid crystal display device for a vehicle has a structure as shown in FIG. 3, in which a liquid crystal panel 12 is attached to a housing 11 made of resin or the like.
On the back side is a light source 14, which is a point light source such as an incandescent light bulb.
The light guide 13 is provided with a light guide 13 that uniformly diffuses and illuminates the display surface of the liquid crystal panel 12, and the light guide 13 includes a reflector 1.
5 is also installed. Generally, the drive circuit 16 is also provided integrally within the housing 11, and the whole is hermetically sealed into a unit, so as to reduce the number of man-hours required during vehicle manufacturing.

<Problems to be Solved by the Invention> However, as explained above, in the conventional liquid crystal display device for a vehicle in which all the components are sealed in the housing 11, the light source 14, which is a heating element,
Since the casing 11 is sealed in one body, the temperature inside the casing 11 increases significantly, and for this reason, the temperature of the liquid crystal panel 12 and the drive circuit 16 tends to rise and exceed the specified temperature. The maximum usable temperature range of liquid crystal display devices is limited to a low level,
This poses a problem that there is a practical limit, and this problem is that when the surroundings are bright such as during the day, the liquid crystal panel 12 becomes darker compared to the outside light, making the light source 14 even brighter. This is incompatible with the desire for a liquid crystal display device for use in vehicles, and has been a very big problem in this type of liquid crystal display device for vehicles.

〓Means for solving the problems〓 The present invention is a specific means for solving the problems that occur in the conventional liquid crystal display device for vehicles as described above. In a vehicle liquid crystal display device in which a light guide and a light source for inputting light into the light guide are built into a housing, at least one end of the light guide is a protruding part to the outside of the housing, and , a liquid crystal display for a vehicle, characterized in that a part of the light guide other than the illumination part and the daylighting part including the protruding part is closely covered with a case made of a material with good thermal conductivity such as metal. By providing a device, the above-mentioned conventional problems are solved.

Embodiments Next, the present invention will be described in detail based on embodiments shown in the drawings.

What is indicated by the reference numeral 1 in FIG. 1 is a casing made of resin or the like, and a liquid crystal panel 2 is built into the casing 1 as in the conventional case. 1 is provided with an opening 1a on the side surface, and the light guide 3 projects to the outside of the housing from the opening 1a to form a protrusion 3a.

At this time, the light guide 3 includes an illumination section 3b that illuminates the liquid crystal panel 2 so that unnecessary light rays do not enter from the protrusion 3a, and a light source 4.
Except for the lighting part 3c that takes in the light from the
A case 5, which also serves the same purpose as the conventional reflector, is provided in close contact with the case 5, but in addition to the above-mentioned purpose, the case 5 also has the purpose of dissipating heat, and therefore has a thermal conductivity of an appropriate thickness. It is made of a material with good quality, such as aluminum.
Note that the light source 4 provided inside the housing 1,
Since the drive circuit 6 is the same as the conventional example,
Detailed explanation of each will be omitted.

In this way, the light guide 3 is made to protrude to the outside of the housing 1 to form the protruding part 3a, and the surface thereof is covered with the case 5 made of a material with good thermal conductivity. Light source 4 inside 1
The heat generated by the heating element such as the protrusion 3a
The heat is then radiated to the outside of the casing.

The one shown in FIG. 2 is another embodiment of the present invention, which is designed to further enhance the heat dissipation effect explained in the previous embodiment. A lamp house portion 5a is formed integrally with the case 5 at a corresponding position using the same material as the case 5. By doing so, almost all of the heat generated by the light source 4 is absorbed by the case 5. The heat is then radiated to the outside of the casing 1. Note that other parts are the same as those in the previous embodiment, so explanations will be omitted.

<Effects of the invention> As explained above, the present invention provides a liquid crystal display device for a vehicle in which at least one end of the light guide is a protruding part to the outside of the casing, and the light guide including the protruding part is Areas other than the lighting section and the daylighting section are tightly covered with a case made of a material with good thermal conductivity such as metal, so that the heat generated inside the casing is transferred from the protruding section to the above-mentioned section. It has the excellent effect of dissipating heat to the outside of the case, increasing the upper limit temperature at which this type of vehicle liquid crystal display device can be used, and eliminating restrictions on its use. This effect is further enhanced by forming a lamp house.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of a liquid crystal display device for a vehicle according to the present invention, FIG. 2 is a cross-sectional view showing another embodiment of the present invention, and FIG. 3 is a cross-sectional view showing a conventional example. be. DESCRIPTION OF SYMBOLS 1... Housing, 1a... Opening, 2... Liquid crystal panel, 3... Light guide, 3a... Protrusion, 3b
...Lighting section, 3c...Lighting section, 4...Light source, 5...
...Case, 5a...Lamp house section, 6...Drive circuit, 7...Instrument panel.

Claims (1)

[Claims for Utility Model Registration] (1) A liquid crystal display for a vehicle, comprising a liquid crystal panel, a light guide provided on the back side of the liquid crystal panel, and a light source that enters light into the light guide, incorporated into a housing. In the device, at least one end of the light guide is a protrusion on the outside of the casing, and a portion of the light guide including the protrusion other than the illumination part and the lighting part is made of a thermally conductive material such as metal. A liquid crystal display device for a vehicle, characterized in that it is tightly covered with a case made of high-quality materials. (2) Utility model registration claim (1) characterized in that a lamp house portion for accommodating the light source is integrally formed at a position corresponding to the lighting portion of the light guide of the case. LCD display devices for vehicles.