JPH0446259Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a liquid crystal display device used for displaying various types of equipment, and more specifically to a liquid crystal display configured so that the liquid crystal panel is illuminated from the back side. It is related to the device.

(Prior Art) An example of the structure of a conventional liquid crystal display device is shown in FIG. In FIG. 3, 1 is a printed wiring board;
A light guide member 2 made of transparent acrylic resin or the like is disposed on the surface of this printed wiring board 1.
Lighting elements 3, such as lamps, are arranged on the surface of the printed wiring board 1 at the periphery of the printed wiring board 1, and the light guide member 2 is illuminated. A liquid crystal panel 5 is disposed on the surface of the light guide member 2 with a transflective plate 4 interposed therebetween. In this way, the signal given to the liquid crystal panel 5 causes
The arrangement of the liquid crystals is appropriately controlled, and the light illuminated from the back surface of the liquid crystal panel 5 is transmitted to the front surface in the form of numbers or letters, thereby displaying numbers or letters.

(Problem to be solved by the invention) In the conventional liquid crystal display device described above, the lighting element 3 that illuminates the light guide member 2 is disposed on the same side of the liquid crystal panel 5 and the printed wiring board 1. Therefore, the heat generated by the lighting element 3 is conducted to the liquid crystal panel 5, and the liquid crystal panel 5 tends to become hot. Due to this heat, the arrangement of the liquid crystals in the liquid crystal panel 5, which should be prevented from transmitting light from the back side, is disturbed, and numbers and characters that should not be displayed are likely to be displayed, which is a so-called crosstalk phenomenon. There was a problem.

In addition, electronic devices have rapidly become smaller in size in recent years.
Along with this, the area of the front panel on which various display sections are disposed has also become smaller. Particularly in so-called car audio products such as in-vehicle radios and tape/disc playback devices, where mounting space is extremely limited, the lack of front panel space is becoming more serious as the number of switches increases due to multi-functionalization. It is. Therefore, the lighting element 3 has to be placed close to the liquid crystal panel 5, and the heat generated by the lighting element 3 is easily conducted to the liquid crystal panel 5.
The situation is such that it is easy to eliminate the crosstalk phenomenon of the liquid crystal panel 5.

(Purpose of the invention) The present invention solves the above-mentioned problems, eliminates the adverse effects on the liquid crystal panel due to the conduction of heat generated by the lighting elements, and makes it possible to reasonably reduce the dead space near the liquid crystal display. The object of the present invention is to provide a liquid crystal display device that has the following characteristics.

(Means for Solving the Problems) In order to achieve the above object, the liquid crystal display device of the present invention has a printed wiring board with a hole, and a light guide member is inserted into the hole at least on the back side of the printed wiring board. A lighting element is disposed on the back side of the printed wiring board at a peripheral edge of the light guide member that is inserted through the board so as to protrude from the back side of the printed wiring board, and the light guide member is disposed on the front side of the printed wiring board. A liquid crystal panel is disposed on the surface of the liquid crystal panel, and the lighting element and the liquid crystal panel are arranged with a distance between them through the light guide member, and the light from the lighting element is guided to the front side by the light guide member, and the liquid crystal panel The light guide member and the printed wiring board are configured to illuminate the liquid crystal panel and to block heat generated by the lighting element from being conducted to the liquid crystal panel.

(Function) The lighting element is arranged on the back side of the printed wiring board, and the liquid crystal panel is arranged on the surface of the light guide member on the front side of the printed wiring board, so there is no light guide between the lighting element and the liquid crystal panel. The mounting space is divided and separated by the interposition of the optical member and the printed wiring board, and the printed wiring board and the light guiding member can block and attenuate the heat generated by the lighting element from being conducted to the liquid crystal panel. Therefore, the liquid crystal panel is not exposed to high temperatures, which can prevent crosstalk from occurring. In addition, since the printed wiring board is placed within the thickness of the light guide member and the liquid crystal panel,
The thickness of the entire device becomes thinner.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a sectional view of one embodiment of the liquid crystal display device of the present invention, and FIG.
FIG. 2 is an exploded perspective view of the liquid crystal display device shown in the figure.

In the figure, 6 is a printed wiring board in which a hole 7 is bored. The light guiding member 8 made of acrylic resin or the like is fitted into the hole 7 of the printed wiring board 6 and inserted through the printed wiring board 6 so as to protrude from both the front side and the back side. Further, the light guide member 8 is formed with a convex portion that protrudes from the back side of the printed wiring board 6. A liquid crystal panel 10 is disposed on the surface of the light guiding member 8 via a transflective plate 9 as in the conventional device. On the back surface of the printed wiring board 6, lighting elements 11, such as lamps, are arranged around the periphery of the light guiding member 8. Note that 12 is a liquid crystal panel fixing frame, and 13 is a switch provided on the printed wiring board 6.

The light from the lighting elements 11, 11 enters the inside of the light guide member 8 from the convex portion of the light guide member 8 protruding from the back surface of the printed wiring board 6, is diffused as appropriate, and reaches the surface of the light guide member 8. To uniformly illuminate the back surface of a disposed liquid crystal panel 10.

Thus, the lighting elements 11, 11 are on the back side of the printed wiring board 6, the liquid crystal panel 10 is on the front side of the printed wiring board 6, and the light guide member 8 is provided between the lighting elements 11, 11 and the liquid crystal panel 10. The mounting space is divided by the intervening printed wiring board 6 and the mounting space is separated from each other compared to conventional devices of this type. As a result, the light from the lighting elements 11, 11 is guided to the liquid crystal panel 10 by the light guide member 8, but the heat generated by the lighting elements 11, 11 is not conducted to the liquid crystal panel 10 by the printed wiring board 6 and the light guide. It can be blocked and damped with member 8. Therefore, the liquid crystal panel 10 is not exposed to high temperature due to the heat of the lighting elements 11, 11, and it is possible to prevent the crosstalk phenomenon from occurring. Furthermore, if the mounting height of the liquid crystal panel 10 from the printed wiring board 6 is the same as that of a conventional device of this type, the thickness of the light guide member 8 in the device of the present invention is large, so the lighting element 11, 11 can be used more efficiently for illuminating the liquid crystal panel 10. The installation height from the printed wiring board 6 to the liquid crystal panel 10 can be made smaller and the installation density can be increased compared to conventional devices of this type, and the device of the present invention can be used for small electronic devices, etc. It is suitable as a display device. Additionally, since the lighting elements 11, 11 are moved to the back side of the printed wiring board 6, peripheral switches can be placed closer to the liquid crystal display, making it possible to reduce the dead space near the display. This makes it possible to reduce the amount without Furthermore, since the printed wiring board 6 is arranged within the thickness of the light guide member 8 and the liquid crystal panel 10, soldering that protrudes from the switch etc. provided on the front side of the printed wiring board 6 to the back side of the printed wiring board 6 is particularly important. portion is included within the thickness, the thickness of the entire device can be reduced,
It is advantageous for downsizing. Moreover, the distance between the surface of the liquid crystal panel 10 and the front side of the printed wiring board 6 is shortened,
In the case where the device of the present invention is installed, for example, on the back side of the escutcheon of a car audio product, the dead space from the escutcheon to the printed wiring board 6 can be made small;
Further, small switches and the like provided on the front side of the printed wiring board 6 can be easily operated from the front side of the escutcheon.

(Effect of the invention) As explained above, in the liquid crystal display device according to the invention, a hole is formed in a printed wiring board, a light guide member is inserted through the hole, and the above-mentioned printing is performed at the periphery of the light guide member. A lighting element is arranged on the back side of the wiring board to illuminate the light guide member from the back side, and a liquid crystal panel is arranged on the surface of this light guide member to illuminate the liquid crystal panel. The panel is thermally separated by a light guide member and a printed wiring board.
It is possible to suppress the adverse thermal effects of the lighting elements and reliably prevent the occurrence of crosstalk phenomena.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of one embodiment of the liquid crystal display device of the present invention, FIG. 2 is an exploded perspective view of the liquid crystal display device shown in FIG. 1, and FIG. 3 is a conventional liquid crystal display device. FIG. 2 is a diagram showing an example of the structure of the device. 1, 6... Printed wiring board, 2, 8... Light guiding member, 3, 11... Lighting element, 5, 10... Liquid crystal panel, 7... Hole.

Claims (1)

[Scope of utility model registration request] A hole is formed in the printed wiring board, a light guiding member is penetrated and inserted into the hole so as to protrude at least to the back side of the printed wiring board, and a peripheral edge of the light guiding member protruding to the back side of the printed wiring board A lighting element is arranged on the back side of the printed wiring board, a liquid crystal panel is arranged on the surface of the light guide member on the front side of the printed wiring board, and the lighting element and the liquid crystal panel are connected through the light guide member. The light guiding member guides the light from the lighting element to the front side to illuminate the liquid crystal panel, and also prevents heat generated by the lighting element from being conducted to the liquid crystal panel. and a liquid crystal display device configured to be blocked by a printed wiring board.