JP3778394B2 - Liquid crystal display - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display device, and more particularly to a temperature detection element mounting structure for temperature compensation.
[0002]
[Prior art]
The liquid crystal display device as an actual product form is provided with a box-shaped housing 10 having a display window 11 on the upper surface, as illustrated in the cross-sectional view of FIG. A panel 20 is arranged.
[0003]
In addition, in the housing 10, the control circuit board 30 is disposed on the back side of the liquid crystal display panel 20 together with the liquid crystal display panel 20. In this example, a backlight is further provided between the liquid crystal display panel 20 and the control circuit board 30. 40 is arranged. The liquid crystal display panel 20 and the control circuit board 30 are electrically connected by a flexible printed wiring board 50.
[0004]
[Problems to be solved by the invention]
By the way, in order to keep the display of the liquid crystal properly, it is necessary to compensate the temperature by changing the drive voltage to be applied according to the ambient temperature. Therefore, in applications such as a notebook personal computer, it is often to make the user the volume that was installed to the outside match the display of taste and adjust manually, in the case of the stomach applications to avoid the cumbersome manual adjustment is, In order to perform temperature compensation automatically, a temperature detecting element for detecting the ambient temperature is provided.
[0005]
In many cases, the thermistor TH is used as the temperature detection element. Conventionally, the thermistor TH is mounted on the control circuit board 30 from the viewpoint of easy mounting.
[0006]
However, since the thermistor TH is gradually heated by the heat generated from the backlight 40 at this mounting position, the ambient temperature of the liquid crystal display panel 20 that should be detected cannot be detected accurately.
[0007]
Incidentally, even when a cold cathode fluorescent lamp (CFL) is used for the backlight 40, heat is generated at about 40 to 50 ° C., and the space between the backlight 40 and the control circuit board 30 tends to be narrowed with downsizing of the apparatus. Therefore, the above problem becomes more prominent.
[0008]
Further, when there is a heating element such as an inverter circuit or a step-up transformer for driving the backlight 40 on the control circuit board 30, the thermistor TH is also heated by this.
[0009]
The present invention has been made to solve such a problem, and an object of the present invention is to provide a liquid crystal display device which can detect the ambient temperature of the liquid crystal display panel more accurately.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a housing having a display window, a liquid crystal display panel provided along the display window of the housing, and a control disposed on the back side of the liquid crystal display panel in the housing. A backlight that is turned on with heat generation is disposed between the liquid crystal display panel and the control circuit board, and the liquid crystal display panel and the control circuit board are arranged along an inner surface of the side wall of the housing. In a liquid crystal display device electrically connected via a flexible printed wiring board drawn around, a temperature sensing element for temperature compensation is mounted on the flexible printed wiring board, and the temperature sensing element is the flexible printing circuit. Using the wiring board as a heat shield, facing the inner surface of the side wall of the housing of the flexible printed wiring board opposite to the backlight It is characterized in that it is arranged on that side.
[0011]
As described above, the temperature detection element is mounted not on the control circuit board but on the flexible printed wiring board, so that the thermal influence on the temperature detection element from the backlight and the heat generating component on the control circuit board is greatly reduced. Is done. Further, by connecting the temperature detecting element to a predetermined wiring of the flexible printed wiring board, the existing configuration can be completed with a minimum modification.
[0012]
In the present invention, since the temperature sensing element is mounted on the side facing the inner surface of the side wall of the housing of the flexible printed wiring board, a flexible printed wiring board itself is Ri Do and heat shields, the temperature sensing element and more It can be effectively protected from the heating element.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, in order to better understand the technical idea of the present invention, a preferred embodiment will be described with reference to FIGS. In this embodiment, the same reference numerals are used for portions that may be regarded as the same as or the same as the configuration of FIG. 4 described above.
[0014]
1 is a cross-sectional view similar to FIG. 4 of the liquid crystal display device in this embodiment. FIG. 2 is a left side view of the inside of the liquid crystal display device seen through from the left side, and FIG. FIG. 3 is a plan view with the liquid crystal display panel 20 removed.
[0015]
Also in this embodiment, the liquid crystal display panel 20 is disposed along the display window 11 in the housing 10, and the backlight 40 and the control circuit board 30 are disposed on the back side thereof.
[0016]
The liquid crystal display panel 20 and the control circuit board 30 are electrically connected by a flexible printed wiring board 50. In this embodiment, the flexible printed wiring board 50 includes a first printed wiring board 51 and a second printed wiring board 51. What connected the printed wiring board 52 is used.
[0017]
A card edge type terminal 51a to be inserted into a connector 31 provided on the control circuit board 30 is provided at one end on the first printed wiring board 51 side, and the other end on the second printed wiring board 52 side. Is connected to a terminal portion of the liquid crystal display panel 20 through, for example, an anisotropic conductive connector (not shown).
[0018]
That is, the flexible printed wiring board 50 is routed from the connector 31 of the control circuit board 30 along the inner surface of the side wall of the housing 10 to reach the terminal portion of the liquid crystal display panel 20. A thermistor TH as a temperature detection element is mounted on the plate 50.
[0019]
In this embodiment, the thermistor TH is attached to the first printed wiring board 51 side, but may be attached to the second printed wiring board 52 side. In any case, since the thermistor TH is moved away from the backlight 40 as the heating element and the heat generating component of the control circuit board 30, the thermal influence from them is reduced, and the temperature closer to the periphery of the liquid crystal display panel 20 can be detected. It becomes possible.
[0020]
When the thermistor TH is mounted on the flexible printed wiring board 50, as shown in FIG. 1, the side facing the inner surface of the side wall of the housing 10 (the flexible printed wiring board 50 is viewed from the center inside the housing). Preferably, the flexible printed wiring board 50 itself becomes a heat shield, and the thermal influence from the backlight 40 and other heat generating components on the thermistor TH is more effectively reduced. .
[0021]
Further, by selecting a predetermined wiring from a large number of wirings formed on the flexible printed wiring board 50 and mounting the thermistor TH on the wiring, there is no need to newly draw a wiring for the temperature detection signal. , With minimal design changes.
[0022]
【The invention's effect】
As described above, according to the present invention, the temperature sensing element for temperature compensation is mounted on the flexible printed wiring board that connects the liquid crystal display panel and its control circuit board. The thermal influence from the heat generating components on the backlight and the control circuit board is greatly reduced, and the temperature closer to the periphery of the liquid crystal display panel can be detected.
[0023]
Further, by mounting the temperature detection element on the predetermined wiring of the flexible printed wiring board, it is not necessary to newly draw a wiring for the temperature detection signal, and it is possible to cope with the minimum design change.
[0024]
Furthermore, since the flexible printed wiring board itself becomes a heat shield by mounting the temperature detecting element on the side of the flexible printed wiring board facing the inner wall of the side wall of the housing, the temperature detecting element is more effectively heated. Can be protected from.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a liquid crystal display device as one embodiment of the present invention.
FIG. 2 is a left side view of the interior of the liquid crystal display device according to the embodiment.
FIG. 3 is a plan view in which a liquid crystal display panel is removed from the liquid crystal display device of the embodiment and the inside thereof is seen through.
FIG. 4 is a cross-sectional view showing a liquid crystal display device as a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Housing 11 Display window 20 Liquid crystal display panel 30 Control circuit board 40 Backlight 50 Flexible printed wiring board TH Temperature detection element (thermistor)

Claims (1)

A housing having a display window, a liquid crystal display panel provided along the display window of the housing, and a control circuit board disposed on the back side of the liquid crystal display panel in the housing, the liquid crystal display panel, A backlight that is turned on with heat generation is disposed between the control circuit board and the liquid crystal display panel and the control circuit board via a flexible printed wiring board that is routed along the inner surface of the side wall of the housing. In an electrically connected liquid crystal display device,
A temperature sensing element for temperature compensation is mounted on the flexible printed wiring board, and the temperature sensing element uses the flexible printed wiring board as a heat shield, and the flexible printed wiring board is opposite to the backlight. A liquid crystal display device, wherein the liquid crystal display device is disposed on a side of the housing facing the inner surface of the side wall .

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