JPH11153785A - Liquid crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal device capable of accurately detecting a change in temperature of a liquid crystal panel by contriving location of a temperature sensor. SOLUTION: A liquid crystal device 1 is arranged on the back side of a liquid crystal panel 2 and the liquid crystal panel 2, and has a backlight 3 uniformly illuminating an effective screen 2a of the liquid crystal panel 2, a control board 5 for controlling a drive of the liquid crystal panel 2, and a temperature sensor 35 for detecting the temperature of the liquid crystal panel 2. The temperature sensor 35 is arranged on a side of 1st edge 21 which is the short side specifying the surroundings on the effective screen 2a. By arranging the temperature sensor 35 at such a position, it is possible to detect temperature changes of the liquid crystal panel 2 without being influenced by an installation place, etc. of the liquid crystal device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device used for a display device such as a car television and a pachinko machine.

[0002]

2. Description of the Related Art A liquid crystal device basically comprises a liquid crystal panel, a backlight disposed on the back side of the liquid crystal panel, and a control board for controlling the driving of the liquid crystal panel. .

In a liquid crystal device, the display characteristics of the liquid crystal panel depend on the temperature. Therefore, in order to always obtain high display quality, it is necessary to change the driving conditions according to the temperature change of the liquid crystal panel. For this reason, there has been proposed a liquid crystal device having a configuration in which a temperature sensor is mounted in the device and driving conditions of the liquid crystal panel are changed according to the detection result of the temperature sensor. As the liquid crystal device, for example, JP-A-5-224201, JP-A-3-104388
And Japanese Utility Model Laid-Open Publication No. 3-107983.

In the liquid crystal device disclosed in Japanese Patent Application Laid-Open No. 5-224201, a temperature sensor is disposed near a light source lamp of a backlight. In Japanese Utility Model Laid-Open No. 3-104388 and Japanese Utility Model Laid-Open No. 3-107983, a temperature sensor is arranged on a control board.

[0005]

The major factors that determine the temperature of the liquid crystal panel are the heat generated by the light source lamp of the backlight and the environmental temperature (air temperature). For this reason,
It is desirable that the temperature sensor be disposed at a position where the temperature change of the liquid crystal panel, which changes due to both factors, can be reliably detected. However, in the liquid crystal devices disclosed in the respective publications, this point is not considered at all.

In view of the above, an object of the present invention is to propose a liquid crystal device capable of accurately detecting the temperature of a liquid crystal panel that changes depending on the heat generation of a backlight and the environmental temperature by devising a position of a temperature sensor. Is to do.

[0007]

In order to solve the above-mentioned problems, in a liquid crystal device according to the present invention, a liquid crystal panel, a backlight disposed on the back side of the liquid crystal panel, and illuminating the liquid crystal panel; In a liquid crystal device having a control board for driving and controlling a panel and a temperature sensor for detecting a temperature of the liquid crystal panel, the temperature sensor is arranged on a side of the effective screen.

[0008] In a liquid crystal device, when used in a car, the rear surface of the product is generally exposed to sunlight, and the temperature of a board (circuit board) on which electronic components such as ICs are mounted is higher than that of a liquid crystal panel. Easy to change. This is remarkable when the liquid crystal device is installed on the dashboard of the car. Further, a liquid crystal device is installed near the outlet of an air conditioner of a car, and the temperature of the liquid crystal device may change by operating the air conditioner. Also in this case, the temperature of the boards tends to change more easily than the liquid crystal panel.

In the liquid crystal devices disclosed in Japanese Utility Model Laid-Open Nos. 3-104388 and 3-107983, since the temperature sensor is disposed on the control board, the temperature change of the liquid crystal panel can be accurately detected. Can not.
Also, in the liquid crystal device disclosed in Japanese Patent Application Laid-Open No. 5-224201, since the temperature sensor is disposed near the light source lamp of the backlight, the temperature change of the liquid crystal panel can be accurately detected as described above. Difficult to do.

It is conceivable that the control board is arranged on the side of the effective screen of the liquid crystal panel, and a temperature change of the liquid crystal panel is detected by a temperature sensor installed on the control board. However, arranging the control board on the side of the effective screen increases the area of a portion other than the screen on the front of the apparatus, which is disadvantageous for downsizing the apparatus. In the future, as the size of the liquid crystal device is reduced, restrictions on the location of the control board will increase. Under such restrictions, it is extremely difficult to install the control board in a place where the temperature change of the liquid crystal panel is accurately reflected. That is, if the temperature sensor is arranged on the control board, the temperature change of the liquid crystal panel cannot be accurately detected.

On the other hand, in the liquid crystal device of the present invention, since the temperature sensor is disposed on the side of the effective screen of the liquid crystal panel, the temperature sensor can accurately detect a change in the temperature of the liquid crystal panel. In particular, when the temperature of the control boards is more easily changed than that of the liquid crystal panel due to, for example, sunlight on the back of the product, the temperature change of the liquid crystal panel can be detected accurately and easily. Further, since there is no restriction that the temperature sensor be installed on the control board, it does not hinder compactness of the device. As described above, according to the present invention, it is possible to accurately detect the temperature change of the liquid crystal panel without increasing the size of the device and without being influenced by the use environment, only by disposing the temperature sensor on the side of the liquid crystal panel. Can be.

Since the temperature of the liquid crystal panel may be partially different due to the heat generated from the backlight or the like, the position of the temperature sensor is determined when the effective screen of the liquid crystal panel has a horizontally long rectangular shape. It is desirable to set the center in the side portion of the short side of the effective screen. By arranging in such a position, the average temperature of the entire liquid crystal panel can be detected.

As a light source lamp for a backlight, there is a light source lamp having a U-shaped arc tube arranged so as to surround three sides of a horizontally long rectangular liquid crystal panel. When a backlight having such a light source lamp is used, the temperature sensor is desirably disposed at a side position of the liquid crystal panel on which the arc tube is disposed. By arranging in such a position, it is possible to detect a temperature change in a portion reflecting both the heat generated from the arc tube of the light source lamp and the environmental temperature. In this case, it is more preferable that the temperature sensor is arranged at the center of the side portion of the short side of the liquid crystal panel. With this arrangement, it is possible to detect an average temperature change of the liquid crystal panel in which both the heat generated from the arc tube and the environmental temperature change due to factors.

Here, the control board can be disposed on the back side of the backlight. In this case, wiring to the temperature sensor can be easily performed by pulling out from the control board via the backlight and the side surface of the liquid crystal panel to the front side of the liquid crystal panel.

When a shield plate is arranged so as to cover the periphery of the liquid crystal panel, it is preferable that the temperature sensor be arranged in a concave portion formed by drawing the shield plate. By forming such a concave portion, the strength of the shield plate itself can be increased.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid crystal device to which the present invention is applied will be described below with reference to the drawings. FIG. 1 is a perspective view showing the external shape of the liquid crystal device. 2A is a partial cross-sectional view of the liquid crystal device, and FIG. 2B is an enlarged cross-sectional view illustrating a portion where the temperature sensor is attached.

As shown in these figures, the liquid crystal device 1 comprises:
It has a liquid crystal panel 2, a display unit 4 having a backlight 3 for uniformly illuminating the liquid crystal panel 2, and a control unit 6 having a control board 5 for driving and controlling the liquid crystal panel 2.

In the display unit 4, the liquid crystal panel 2 and the backlight 3 are basically held in a state sandwiched by two shield plates 7 and 8 on the rear side and the front side. The rear-side shield plate 7 includes a rectangular bottom plate portion 7a and a side plate portion 7b that rises at right angles from the four circumferential edges of the bottom plate portion 7a. The backlight 3 having a plate shape as a whole is arranged on the bottom plate portion 7b.

The backlight 3 is of an edge light type, and has a rectangular light guide plate 15 made of acrylic resin or the like.
And a U-shaped fluorescent lamp 16 having arc tube portions 31, 32, 33 extending along three sides except one short side of the light guide plate 15, A reflector 1 having a U-shaped cross section for guiding the emitted light into the light guide plate 15
7. In the light guide plate 15, a light diffusion sheet 18 is provided on the front surface, while a reflection sheet 19 is provided on the back surface.

In the backlight 3, the fluorescent lamp 16
The light emitted from the light guide 16 is guided into the light guide plate 15 by the reflector 16. The light guided into the light guide plate is made into a planar light with uniform brightness by the light diffusion sheet 18 and emitted while repeating multiple reflections inside the light guide plate.

The backlight 3 is covered with a resin frame 9. The resin frame 9 has a rectangular frame portion 9b having a rectangular opening 9a serving as a light passage opening.
And a side plate portion 9c extending from the frame portion 9b to the rear side and the front side. The backlight 3 is sandwiched by the frame portion 9b and the bottom plate portion 7a of the rear shield plate 7 from both the rear and front sides. The side plate portion 7c extends so as to be in contact with the side plate portion 7b of the rear shield plate 7, and the resin frame 9 is supported by the rear shield plate 7 from the side. A buffer member 10 is inserted between the side plate portion 7c and the backlight 3. The liquid crystal panel 2 having a rectangular shape is disposed on the front side of the frame portion 9b of the resin frame 9.

On the front side of the liquid crystal panel 2, a front side shield plate 8 is arranged. The front shield plate 8 includes a frame portion 8b having a rectangular opening 8a defining a rectangular effective screen 2a of the liquid crystal panel 2, and a frame portion 8a.
And a side plate portion 8c bent at a right angle from the edge of the rear surface to the rear side. The liquid crystal panel 2 is held from both the front and back sides by the frame portion 8a and the frame portion 9b of the resin frame 9. The side plate portion 8c is connected to the rear shield plate 7 and the side plate portion 7b. In summary, in the liquid crystal device 1, the backlight 3, the resin frame 9, and the liquid crystal panel 2 are arranged in this order between the two shield plates 7 and 8 from the back to the front.

The control unit 6 is arranged at a position laterally offset on the back side of the bottom plate portion 7a of the back side shield plate 7. The control unit 6 has a dish-shaped case 11 in which the control board 5 is installed. When the control board 5 is installed, the case 11 is attached to the bottom plate portion 7a of the rear shield plate 7.
It is attached to the back side of.

Here, the liquid crystal device 1 has a temperature sensor 35 for detecting the temperature of the effective screen 2a of the liquid crystal panel 2. This temperature sensor 35 is arranged on the side of the effective screen 2a.

More specifically, in the liquid crystal device 1, the effective screen 2a of the liquid crystal panel 2 has the first,
It has second, third, and fourth sides 21, 22, 23, and 24. The first and fourth sides 21 and 24 are opposed short sides, and the second and third sides 22 and 23 are opposed long sides. The arc tube portions 31, 32, and 33 of the U-shaped fluorescent lamp 16 of the backlight 3 correspond to the effective screen 2
a, first, second and third sides 21, 22, and 2 of a
It is parallel to 3. The arrangement position of the temperature sensor 15 is as follows.
It is the center of the side of the short side (first side) 21 of the effective screen 2a. That is, the position is a side position of the liquid crystal panel 2 where the arc tube part 31 is arranged, and
Is the center of the side portion of the short side of

Next, the mounting structure of the temperature sensor will be described. At the center of one short side of the frame portion 8b of the front shield plate 8, a groove 8d extending horizontally from the outside toward the opening 8a is formed. The groove 8d is formed to be a concave portion by drawing. By forming such a groove 8d, no protrusion is generated on the upper side of the front side shield plate 8, and
The strength of the shield plate 8 can be improved.

The temperature sensor 35 has a detecting section 35a for actually detecting the temperature, and a flexible cable section 35b for connecting the detecting section 35a to the control board 5 by wiring. The detecting portion 35a is installed in the groove 8d, and the flexible cable portion 35b is routed to the control board 5 via the side plate portions 7b and 8c of the rear and front shield plates 7 and 8. In this example, in this state, in order to protect the detection unit 35a from the outside and further fix the flexible cable unit 35d,
The acetate cloth tape 37 is stuck.

When the liquid crystal device 1 is used in a vehicle, the rear surface of the product is generally exposed to sunlight, and the temperature of a board (circuit board) on which electronic components such as ICs are mounted is lower than that of the liquid crystal panel 2. It is easier to change. This is remarkable when the liquid crystal device 1 is installed on the dashboard of a car. In addition, the liquid crystal device 1
Is installed, and the temperature of the liquid crystal device 1 may be changed by operating the air conditioner. Also in this case, the temperature of the boards is more likely to change than the liquid crystal panel 2. For this reason, Japanese Utility Model Laid-Open No. 3-104388 and Japanese Utility Model Laid-Open
As in the liquid crystal device disclosed in JP-A-10-107983,
If the temperature sensor is arranged on the control board, the temperature change of the liquid crystal panel cannot be accurately detected, and the driving condition of the liquid crystal panel cannot be changed following the temperature change of the panel. In addition, Japanese Patent Application Laid-Open No. H5-2224
The same can be applied to the case where the temperature sensor is arranged near the light source lamp of the backlight as in the liquid crystal device disclosed in Japanese Patent Application Publication No. 01-001.

On the other hand, in the liquid crystal device 1, the temperature sensor 35 is arranged on the side of the effective screen 2 a of the liquid crystal panel 2, so that the temperature of the control board is higher than that of the liquid crystal panel 2 due to the location of the liquid crystal device. Even when the temperature of 5 is more likely to change, the temperature change of the liquid crystal panel 2 can be detected accurately. Accordingly, the driving conditions can be changed following the temperature change of the liquid crystal panel 2 without being affected by the use environment. Further, since there is no restriction that the temperature sensor 35 must be installed on the control board 5, it does not hinder compactness of the apparatus.

In the liquid crystal device 1, the temperature sensor 35 is disposed on the side of the liquid crystal panel 2 where the arc tube portion 31 is disposed, and at the center of the short side of the liquid crystal panel 2. is there. Therefore, it is possible to accurately detect an average temperature change at a location where both the environmental temperature and the heat generated by the fluorescent lamp 16 are more accurately reflected, and to optimize the driving conditions of the entire liquid crystal panel.

In particular, as shown in FIG.
This is effective when used so that the effective screen 2a of the liquid crystal panel 2 has a horizontally long rectangular shape. That is, when the liquid crystal device 1 is used in a state as shown in FIG. 3, the temperature near the second side 22 of the effective screen 2a of the liquid crystal panel 2 becomes higher than the third side 23.
Higher than the temperature in the vicinity of. At this time, the first side 2
By arranging the temperature sensor 35 at the center of one side portion, the average temperature change of the entire liquid crystal panel can be detected more accurately.

The temperature sensor 35 can be placed at any position on the side of the effective screen 2a of the liquid crystal panel 2 as long as the temperature change of the liquid crystal panel 2 can be accurately detected. What is necessary is just to determine according to the shape of the light source lamp used for the backlight 3 and the use condition of the liquid crystal device 1.

Further, the backlight 3 is not limited to the one having the U-shaped fluorescent lamp 16, but the one in which a straight tube fluorescent lamp is arranged on one side of the light guide plate 15 or the light guide plate 1.
5 may be one in which straight tube fluorescent lamps are arranged on two sides.

[0034]

As described above, in the liquid crystal device of the present invention, the temperature sensor for detecting the temperature of the liquid crystal panel is arranged on the side of the effective screen of the liquid crystal panel. Therefore, even when the temperature of the control boards is more likely to change than that of the liquid crystal panel due to, for example, sunlight on the back of the product, the temperature change of the liquid crystal panel can be accurately detected. As a result, it is possible to realize a liquid crystal device that can always display high-quality images regardless of the use environment. Further, since there is no restriction that the control board is arranged on the side of the liquid crystal panel, it does not hinder compactness of the device.

[Brief description of the drawings]

FIG. 1 is a perspective view of a liquid crystal device to which the present invention is applied.

FIG. 2 is a schematic sectional configuration diagram showing a part of the liquid crystal device shown in FIG.

FIG. 3 is a diagram illustrating a use state of the liquid crystal device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal device 2 Liquid crystal panel 2a Effective screen 3 Backlight 5 Control board 7 Rear side shield plate 8 Front side shield plate 9 Resin frame 10 Buffer member 21 First side 22 Second side 23 Third side 24 Fourth Sides 31, 32, 33 Arc tube 35 Temperature sensor 37 Acetate cloth tape

Claims (6)

[Claims] 1. A liquid crystal panel, a backlight disposed on the back side of the liquid crystal panel and illuminating the liquid crystal panel, a control board for driving and controlling the liquid crystal panel, and detecting a temperature of the liquid crystal panel. A liquid crystal device having a temperature sensor, wherein the temperature sensor is arranged on a side of an effective screen. 2. The liquid crystal panel according to claim 1, wherein an effective screen of the liquid crystal panel has a horizontally long rectangular shape, and the temperature sensor is disposed at a center of a side portion of a short side of the effective screen. Characteristic liquid crystal device. 3. The liquid crystal panel according to claim 1, wherein:
The light source lamp of the backlight is provided with a U-shaped arc tube arranged so as to surround three sides of the liquid crystal panel, and the temperature sensor is arranged with the arc tube. A liquid crystal device disposed at a side position of the liquid crystal panel. 4. The temperature sensor according to claim 3,
A liquid crystal device, wherein the liquid crystal panel is arranged at a center of a side portion on a short side of the liquid crystal panel. 5. The control board according to claim 1, wherein the control board is disposed on a back side of the backlight, and wiring to the temperature sensor is provided from the control board to the backlight and the backlight. A liquid crystal device, which is drawn out to the front side of the liquid crystal panel via a side surface of the liquid crystal panel. 6. The liquid crystal panel according to claim 1, further comprising a shield plate disposed so as to cover a periphery of the liquid crystal panel, wherein the temperature sensor performs drawing on the shield plate. A liquid crystal device, wherein the liquid crystal device is disposed in a recess formed by applying the liquid crystal.