JP6265831B2 - Liquid crystal display - Google Patents

Description

  The present invention relates to a liquid crystal display device.

  In general, in the case of multi-vision in which a large screen display is configured using a liquid crystal display device, a plurality of liquid crystal display devices having a size of about 40 to 60 inches using, for example, an LCD (Liquid Crystal Display) are combined. Conventionally, a cold cathode fluorescent lamp (CCFL: Cold Cathode Fluorescent Lamp) has been used as a light source of a liquid crystal display device using an LCD. However, in recent years, a mainstream is a backlight that illuminates the liquid crystal panel from the back side by arranging a plurality of light emitting diodes (LEDs) directly under the LCD panel as a light source.

  The video display unit of the liquid crystal display device includes a diffusion sheet and a diffusion plate disposed on the back surface of the liquid crystal panel, and backlight light passing through them forms an image displayed on the video display unit. The LED used for the backlight is basically disposed in the backlight housing of the liquid crystal panel, and all of its constituent members are covered with a sheet metal, and a panel drive board and the like are disposed on the back of the sheet metal. These substrates and the internal LCD module are commercialized as liquid crystal panel modules in a state where they are connected by lead wires.

  The liquid crystal display device is configured in a state in which a casing (hereinafter referred to as “chassis casing”) for housing various electrical components for image operation is attached to the rear sheet metal part of the liquid crystal panel module. Furthermore, in order to enable the liquid crystal display device to be used stably for a long time, a cooling fan for cooling the components in the chassis is arranged in the chassis to ensure the reliability of the components in the chassis. .

  In recent years, a multi-vision that configures a large screen display using the liquid crystal display device having the above configuration is installed as a public display device in any space such as a public place, a station, an airport, or a bank lobby. In particular, when configuring multivision, it is required to design (narrow frame) so that the portion (joint width) where the images associated with the top, bottom, left and right of each liquid crystal display device are not displayed is as small as possible. . Therefore, a thin metal plate (0.5 mm or less) is used as the metal plate constituting the narrow frame, and the narrow frame is used by being fixed or held by a number of screws.

  In the liquid crystal display device, there is a problem that the temperature of the liquid crystal display device rises due to heat generated from the backlight and heat generated from various electric components in the chassis housing. Therefore, for example, Patent Document 1 discloses that heat generated from the backlight of the liquid crystal panel module and heat generated from the chassis circuit (various electrical components in the chassis housing) are quickly released out of the housing of the liquid crystal display device. A method of suppressing an increase in the in-machine temperature of a liquid crystal display device is disclosed.

JP-A-10-96898

  In the in-machine temperature control method described in Patent Document 1, usually, a heat radiating hole is arranged at an appropriate position of the casing, and outside air is actively taken into the liquid crystal panel by the intake fan, and the exhaust fan is installed inside the casing. The heated air is exhausted and cooled. This is effective considering only the cooling structure. However, since a large amount of outside air is sucked into the liquid crystal panel, fine dust contained in the outside air also invades, so that the dust adheres to the backlight and the diffusion plate and develops image defects such as color unevenness. An event has occurred.

  Especially in multi-visions used for business use, etc., the environment used is a harsh environment where dust is likely to be generated in public places such as stations, airports or bank lobbies, thus preventing dust from entering the liquid crystal panel module. Is a very important issue.

  Even in the case of a general liquid crystal display device, a cooling fan is usually used in the chassis housing, and heat generated in the chassis housing is exhausted to the outside air. At this time, the inside of the chassis housing is in a negative pressure state with respect to the external air pressure due to the influence of the cooling fan. Further, the negative pressure state due to the cooling fan also affects the inside of the liquid crystal panel module, and the negative pressure state is similarly reached.

  A negative pressure state in the liquid crystal panel module will be described. This is a small opening hole on the back of the liquid crystal panel module, specifically, a liquid crystal panel module control wiring hole from the chassis housing side, a service screw hole, and a small amount of metal generated in the sheet metal of the liquid crystal panel module housing. This includes gaps and gaps in the fitting holes of plastic parts. The space on the chassis housing side and the space in the liquid crystal panel module are penetrated by the gaps or opening holes as shown above, so if a negative pressure occurs in the chassis housing, Negative pressure conditions will be affected.

  In order to eliminate the above-mentioned gap or opening hole, it is conceivable that a part is covered with a tape or the like, but actually it is difficult to completely cover it, and countermeasure parts and work costs are generated. Even if a countermeasure is taken, if a slight gap or opening hole remains, the liquid crystal panel module is in a negative pressure state, so that the reliability performance of the liquid crystal display device is lowered.

  As described above, since the inside of the liquid crystal panel module is in a negative pressure state with respect to the outside air, the outside air continues to enter the liquid crystal panel module. Therefore, dirt such as fine dust contained in the outside air is diffused and the liquid crystal panel. Such problems as brightness deterioration and color unevenness occur.

  Therefore, the present invention provides a liquid crystal display device capable of preventing problems such as luminance deterioration and color unevenness caused by dirt such as fine dust contained in the outside air adhering to components in the liquid crystal panel module. The purpose is to do.

  The liquid crystal display device according to the present invention is disposed on the back side of the liquid crystal panel module having a liquid crystal panel, a backlight, and the liquid crystal panel and a liquid crystal panel housing for housing the backlight. A chassis housing, a liquid crystal panel driving circuit disposed in the chassis housing and driving the liquid crystal panel, and disposed in the chassis housing and creating a negative pressure state in the chassis housing A cooling fan that cools the liquid crystal panel drive circuit by taking in the chassis housing, and a filter that is disposed in the chassis housing and filters outside air that passes through the chassis housing and is taken into the cooling fan; A portion of the exhaust of the cooling fan disposed in the chassis housing and passing through the filter Separated, in which and a duct for feeding to the liquid crystal panel housing.

  According to the present invention, a liquid crystal display device takes in outside air into a chassis housing by creating a negative pressure state in the chassis housing, a liquid crystal panel module, a chassis housing, a liquid crystal panel driving circuit that drives the liquid crystal panel, and the chassis housing. The cooling fan that cools the LCD panel drive circuit, the filter that filters the outside air that passes through the chassis housing and is taken into the cooling fan, and a part of the exhaust of the cooling fan that passes through the filter are separated and sent into the housing A duct.

  Therefore, by using a part of the exhaust of the cooling fan that cools the liquid crystal panel drive circuit and blowing air into the liquid crystal panel casing of the liquid crystal panel module, the inside of the liquid crystal panel casing has the same pressure as the outside air, or more than the outside air. A high pressure state (positive pressure state) can be maintained. As a result, it is possible to prevent the entry of dirty air from the outside of the LCD panel casing, thus preventing problems such as brightness deterioration and color unevenness caused by dust adhering to the liquid crystal panel and backlight components in the LCD panel casing. it can.

4 is a rear perspective view of the liquid crystal panel module and the air blowing mechanism in the liquid crystal display device according to Embodiment 1. FIG. FIG. 3 is a rear perspective view of the air blowing mechanism in the liquid crystal display device according to Embodiment 1. 4 is a cross-sectional view of a blower mechanism in the liquid crystal display device according to Embodiment 1. FIG. 4 is a block diagram regarding control of a cooling fan in the liquid crystal display device according to Embodiment 1. FIG. In the liquid crystal display device which concerns on Embodiment 2, it is a rear view of a liquid crystal panel module and a ventilation mechanism. In the liquid crystal display device which concerns on Embodiment 2, it is sectional drawing of a liquid crystal panel module and a ventilation mechanism. It is an enlarged view of the part A of FIG. It is a rear view of the liquid crystal display device which concerns on a base technology. It is a right view of the liquid crystal display device which concerns on a base technology. It is a left view of the liquid crystal display device which concerns on a base technology. In the liquid crystal display device which concerns on a base technology, it is a rear view of a liquid crystal panel module. FIG. 3 is a plan view of a liquid crystal panel module in the liquid crystal display device according to the base technology. In the liquid crystal display device which concerns on a premise technique, it is a left view of a liquid crystal panel module.

<Prerequisite technology>
First, the liquid crystal display device 1 according to the base technology will be described. 8 is a rear view of the liquid crystal display device 1 according to the base technology, FIG. 9 is a right side view of the liquid crystal display device 1, FIG. 10 is a left side view of the liquid crystal display device 1, and FIG. FIG. 12 is a rear view of the liquid crystal panel module 2, FIG. 12 is a plan view of the liquid crystal panel module 2, and FIG. 13 is a left side view of the liquid crystal panel module 2.

  As shown in FIGS. 8 to 10, the liquid crystal display device 1 includes a liquid crystal panel module 2 and a chassis housing 4, and the chassis housing 4 is disposed on the back side of the liquid crystal panel module 2. More specifically, the liquid crystal display device 1 is configured by integrating a chassis housing 4 on the back surface of the liquid crystal panel housing 3 of the liquid crystal panel module 2. A plurality of heat radiating holes 4 a are arranged on the back and side surfaces of the chassis housing 4. In addition, a plurality of heat radiation holes 3 a are also arranged on the back surface of the liquid crystal panel housing 3 where the chassis housing 4 is not provided.

  On the rear surface of the chassis housing 4, for example, two cooling fans (not shown) are disposed on the back side (inside the chassis housing 4) of the heat radiation holes 4 a disposed in the center of the upper end portion. Outside air is taken into the chassis housing 4 by the cooling fan, and the air in the chassis housing 4 is exhausted. FIG. 8 shows a state in which the metal plate on the back surface of the chassis housing 4 is removed, and the arrows in FIG. 8 show the flow of exhausted air. Here, the chassis housing 4 is a housing for housing various electrical components for image operations in the liquid crystal panel module 2.

  Next, the liquid crystal panel housing 3 of the liquid crystal panel module 2 will be described.

  As shown in FIGS. 11 to 13, there are small opening holes and gaps in the liquid crystal panel housing 3 of the liquid crystal panel module 2. For example, the control wiring hole 3 b of the liquid crystal panel housing 3 of the liquid crystal panel module 2, the service screw hole 3 c, and the small gap 3 d generated in the sheet metal of the liquid crystal panel housing 3. Since the space on the chassis housing 4 side and the space in the liquid crystal panel housing 3 of the liquid crystal panel module 2 are penetrated by these small opening holes or gaps, the negative pressure state of the chassis housing 4 is reduced. When this occurs, the negative pressure state also affects the liquid crystal panel casing 3. For this reason, dirt such as fine dust contained in the outside air adheres to the components in the liquid crystal panel housing 3, and problems such as luminance deterioration and color unevenness occur.

  In the liquid crystal display device according to the first embodiment of the present invention, there are problems such as luminance deterioration and color unevenness caused by dirt such as fine dust contained in the outside air adhering to the components in the liquid crystal panel housing 3. It is preventing.

<Embodiment 1>
Embodiment 1 of the present invention will be described below with reference to FIGS. 1 is a rear perspective view of a liquid crystal panel module 2 and a blower mechanism 20 in the liquid crystal display device according to Embodiment 1, FIG. 2 is a rear perspective view of the blower mechanism 20, and FIG. 3 is a blower mechanism. FIG. In the first embodiment, the same components as those described in the base technology are denoted by the same reference numerals and description thereof is omitted. Further, description will be made with reference to FIGS. 8 to 13 as appropriate.

  The liquid crystal display device according to Embodiment 1 includes a chassis housing and a liquid crystal panel module 2 as in the base technology, and the chassis housing is disposed on the back side of the liquid crystal panel module 2. More specifically, the liquid crystal display device is configured such that a chassis housing is integrated with the back surface of the liquid crystal panel housing 3 of the liquid crystal panel module 2. The chassis housing has substantially the same structure as the chassis housing 4 described in the base technology, and thus detailed description thereof is omitted.

  The liquid crystal display device further includes a control unit 15 (see FIG. 4), a liquid crystal panel drive circuit 16 (see FIG. 4), and a blower mechanism 20. The chassis housing houses the liquid crystal panel drive circuit 16, the control unit 15, and the blower mechanism 20. The liquid crystal panel module 2 includes a liquid crystal panel (not shown), a backlight (not shown), a diffusion plate (not shown), and a liquid crystal panel housing 3. Here, the liquid crystal panel housing 3 shown in FIG. 1 is used as a control wiring hole 3b, a service screw hole 3c, and a sheet metal of the liquid crystal panel housing 3 in the same manner as the liquid crystal panel housing 3 shown in FIG. Assume that a small gap 3d is generated.

  The liquid crystal panel housing 3 accommodates a liquid crystal panel, a backlight, and a diffusion plate that are components constituting the liquid crystal panel module 2. The liquid crystal panel includes a video display unit and displays video or text information. The backlight is disposed on the back side of the liquid crystal panel, and irradiates the liquid crystal panel with light through a diffusion plate. The diffuser plate equalizes the brightness of light emitted from the backlight.

  The control unit 15 governs the overall operation of the liquid crystal display device 1 based on a program stored in a ROM (not shown) or the like. The liquid crystal panel drive circuit 16 is a circuit that drives the image operation in the liquid crystal panel module 2, that is, the liquid crystal panel, under the control of the control unit 15.

  As shown in FIGS. 1 to 3, the blower mechanism 20 includes a cooling fan 11, an air purification filter 13 (filter), a blower duct 10 (duct), a pressure sensor 14, and a clean box 12. . The cooling fan 11 cools the liquid crystal panel drive circuit 16 by taking outside air into the chassis case by creating a negative pressure state in the chassis case. A clean box 12 is fixed to the windward side (lower side) of the cooling fan 11, and an air purification filter 13 is attached to the lower part of the clean box 12. The air cleaning filter 13 filters the outside air that passes through the chassis housing and is taken into the cooling fan 11, and supplies purified air from which dust contained in the outside air has been removed to the cooling fan 11.

  The blower duct 10 is attached to the leeward side (upper side and front side) of the cooling fan 11, separates a part of the exhaust of the cooling fan 11 that has passed through the air cleaning filter 13, and sends it into the liquid crystal panel housing 3. Specifically, the air inlet 10 a of the air duct 10 is formed in a shape that can cover only the front part of the cooling fan 11, and the air that has passed through the front part of the cooling fan 11 is sent to the air duct 10. . On the other hand, the air that has passed through the rear portion of the cooling fan 11 is blown to the liquid crystal panel drive circuit 16 to cool the liquid crystal panel drive circuit 16.

  The air outlet of the air duct 10 is formed in a shape capable of covering a region including the control board and the control wiring hole 3b (see FIG. 11) of the liquid crystal panel module 2, and the air duct 10 is formed in the liquid crystal panel housing 3. The air is sent to the control wiring hole 3b of the liquid crystal panel module 2 provided on the back surface of the liquid crystal panel module. The air that has passed through the air duct 10 is blown to the backlight of the liquid crystal panel module 2 through the control wiring hole 3b. That is, the cooling fan 11 serves to exhaust heat inside the chassis and plays a role of blowing air into the liquid crystal panel module 2.

  The air pressure of the cooling fan 11 is controlled so that the internal air pressure of the liquid crystal panel module 2 is at least the same or slightly higher than the external air pressure (positive pressure state) by the air blown from the cooling fan 11. That is, the liquid crystal panel module 2 has a structure that prevents the entry of dirty air from the outside air.

  Further, as shown in FIG. 2, the liquid crystal display device 1 includes an air purification filter 13 for blowing purified air into the liquid crystal panel module 2. Therefore, clean air from which dust has been removed by the air cleaning filter 13 is blown into the blower duct 10.

  As shown in FIG. 3, clean air discharged from the cooling fan 11 passes through the blower duct 10 and is blown into the control wiring hole 3 b of the liquid crystal panel housing 3. A pressure sensor 14 is arranged. The pressure sensor 14 is a sensor that detects the wind pressure of the exhaust gas sent into the liquid crystal panel housing 3. In the present embodiment, for example, a thin, light and flexible polymer sheet-like pressure sensor is selected as the pressure sensor 14 disposed in the air duct 10 having a small installation space. The pressure sensor 14 is electrically connected to the control unit 15 via the signal cable 17.

  The polymer sheet-shaped pressure sensor 14 is a sensor capable of converting the amount of bending deformation into a voltage signal. For this reason, bending deformation occurs in the pressure sensor 14 due to the air blown from the cooling fan 11, and the rotation speed of the cooling fan 11 is controlled by the voltage signal converted according to the bending deformation amount. That is, the control unit 15 controls the rotation speed of the cooling fan 11 based on the wind pressure detected by the pressure sensor 14. Thus, by applying a predetermined wind pressure in the liquid crystal panel housing 3 of the liquid crystal panel module 2, the inside of the liquid crystal panel housing 3 can be controlled to a predetermined atmospheric pressure state.

  Here, the predetermined atmospheric pressure state refers to a positive pressure state that is equal to or relatively small as the external atmospheric pressure. As a result, it is possible to prevent the outside air from entering the liquid crystal panel housing 3 of the liquid crystal panel module 2, and it is possible to use the air purifying filter 13 for a long time. When the deformation is maintained, the polymer sheet-like pressure sensor 14 continuously generates a constant voltage, and can keep the rotation speed of the cooling fan 11 constant.

  When the air cleaning filter 13 disposed in the clean box 12 is clogged with dust, the amount of air blown from the cooling fan 11 is reduced and the wind pressure is reduced. When clogging of the air purifying filter 13 progresses and falls below a predetermined wind pressure, the pressure sensor 14 is less deformed due to a decrease in the wind pressure from the cooling fan 11, so that the output voltage signal is also It will be in a lowered state. Therefore, as shown in FIG. 4, the control unit 15 operates in response to this voltage change so that the rotational speed of the cooling fan 11 is increased so as to keep the deformation amount of the pressure sensor 14 at a predetermined value. By adjusting, the inside of the liquid crystal panel housing 3 of the liquid crystal panel module 2 can be controlled to a predetermined atmospheric pressure state.

  Next, control of the cooling fan 11 will be described. FIG. 4 is a block diagram relating to the control of the cooling fan 11. Normally, when the voltage change V0 of the pressure sensor 14 is detected, the control unit 15 manages the supply voltage to the cooling fan 11 necessary for maintaining the target positive pressure Pa0 as V0. When the air cleaning filter 13 is clogged by dust in the outside air and the blowing pressure cannot maintain the target internal pressure of the liquid crystal panel module 2, the control unit 15 increases the supply voltage to the cooling fan 11 to cool the air. Control is performed so that the rotational speed of the fan 11 increases and the target internal pressure is maintained.

  When the air cleaning filter 13 is clogged with dust, the supply voltage to the cooling fan 11 gradually increases, and the internal pressure of the liquid crystal panel housing 3 of the liquid crystal panel module 2 can be managed to a predetermined value. is there. The control unit 15 determines clogging of the air purification filter 13 based on the wind pressure detected by the pressure sensor 14. When it is determined that the air purification filter 13 is clogged, that is, when the use limit voltage of the cooling fan 11 is reached, the control unit 15 controls the liquid crystal panel drive circuit 16 to control the air. Information (for example, character information) for recommending the replacement of the cleaning filter 13 is displayed on the video display unit of the liquid crystal panel.

  As described above, the liquid crystal display device according to the first embodiment includes the liquid crystal panel module 2, the chassis housing, the liquid crystal panel drive circuit 16 that drives the liquid crystal panel, and creates a negative pressure in the chassis housing. Is passed through the chassis housing to cool the liquid crystal panel drive circuit 16, the air purification filter 13 that filters outside air that passes through the chassis housing and is taken into the cooling fan 11, and the air purification filter 13. A part of the exhaust of the cooling fan 11 is separated, and a blower duct 10 that feeds into the liquid crystal panel housing 3 is provided.

  Therefore, after utilizing a part of the exhaust of the cooling fan 11 that cools the liquid crystal panel drive circuit 16, the air is blown into the liquid crystal panel housing 3 of the liquid crystal panel module 2, thereby allowing the inside of the liquid crystal panel housing 3 to be exposed to the outside air. It is possible to maintain the same pressure or a higher pressure than the outside air (positive pressure state). As a result, it is possible to prevent the entry of dirty air from the outside of the liquid crystal panel housing 3, so that luminance deterioration caused by dust adhering to components such as the liquid crystal panel, the backlight and the diffusion plate in the liquid crystal panel housing 3 can be prevented. Problems such as uneven color can be prevented.

  The liquid crystal display device is disposed in the air duct 10 and detects the wind pressure of exhaust gas sent into the liquid crystal panel housing 3, and the cooling fan 11 based on the wind pressure detected by the pressure sensor 14. Is further provided with a control unit 15 that maintains the inside of the liquid crystal panel housing 3 in a predetermined positive pressure state by controlling the number of rotations. Therefore, by adjusting the wind pressure by the pressure sensor 14 disposed on the air passage of the air duct 10, the inside of the liquid crystal panel housing 3 of the liquid crystal panel module 2 can be controlled to a predetermined positive pressure value (target value). This makes it possible to prevent the ingress of outside air containing dust and to keep the air purifying filter 13 for a long period of time by limiting the pressure to the minimum necessary positive pressure value.

  When the control unit 15 determines the clogging state of the air purification filter 13 based on the wind pressure detected by the pressure sensor 14 and determines that the clogging of the air purification filter 13 is proceeding, the air purification filter 13 Since the information for recommending the replacement is displayed on the image display unit of the liquid crystal panel, the clogging state of the air cleaning filter 13 can be managed, and the air cleaning filter 13 can be replaced at an appropriate time.

<Embodiment 2>
Next, a liquid crystal display device according to Embodiment 2 will be described. FIG. 5 is a rear view of the liquid crystal panel module 2 and the air blowing mechanism 20 in the liquid crystal display device 1 according to Embodiment 2, and FIG. 6 is a cross-sectional view of the liquid crystal panel module 2 and the air blowing mechanism 20. 7 is an enlarged view of a portion A in FIG. 6. FIG. 7A shows a case where the liquid crystal panel is driven (when ON), and FIG. 7B shows a case where the liquid crystal panel is not driven (when OFF). is there. Note that in the second embodiment, the same components as those described in the base technology and the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the second embodiment, the arrangement of the pressure sensor 14 of the blower mechanism 20 is different from that in the first embodiment. In the first embodiment, the pressure sensor 14 is arranged in the air duct 10, and some structural device is required to draw the signal cable 17 of the pressure sensor 14 from the liquid crystal panel housing 3 of the liquid crystal panel module 2 to the outside. It is.

  On the other hand, in the present embodiment, as shown in FIGS. 5 to 7A and 7B, the liquid crystal panel housing 3 is connected to the back surface of the liquid crystal panel housing 3 to communicate with the liquid crystal panel housing 3. A small opening hole 3f is provided, and the pressure sensor 14 is disposed in a state of being in contact with the peripheral portion of the opening hole 3f outside the liquid crystal panel housing 3. More specifically, the pressure sensor 14 is arranged in a state in which one side of the pressure sensor 14 is fixed in an attachment portion 18 fitted and attached to the opening hole 3f, and the attachment portion 18 is located on the opening hole 3f side. An opening 18a that opens is provided.

  Therefore, the pressure sensor 14 can detect the wind pressure of the air flowing out from the opening hole 3f of the liquid crystal panel housing 3 when the liquid crystal panel is driven, and the liquid crystal panel when the liquid crystal panel is not driven. It is possible to close the opening hole 3f of the panel housing 3. Since the signal cable 17 of the pressure sensor 14 is arranged outside without being drawn into the liquid crystal panel housing 3, the signal cable 17 can be routed without opening the opening hole 3f, and fine dust from the outside air can be routed. It is also possible to prevent intrusion of the pressure sensor 14 and the like, and the mounting workability of the pressure sensor 14 is improved.

  As described above, in the liquid crystal display device according to the second embodiment, the liquid crystal panel housing 3 is provided with the opening hole 3 f that communicates with the inside of the liquid crystal panel housing 3. Based on the pressure sensor 14 that is disposed in contact with the peripheral portion and detects the wind pressure of the air flowing out from the liquid crystal panel housing 3, and the rotational speed of the cooling fan 11 based on the wind pressure detected by the pressure sensor 14. Is further provided with a control unit 15 that holds the inside of the liquid crystal panel housing 3 in a predetermined positive pressure state. Therefore, the signal cable 17 can be routed without opening the opening hole 3f, and fine dust and the like can be prevented from entering from the outside air, and the workability of mounting the pressure sensor 14 is improved.

  Further, the pressure sensor 14 arranged in contact with the peripheral portion of the opening hole 3f closes the opening hole 3f when the liquid crystal panel is not driven so as to prevent intrusion of air from the outside of the liquid crystal panel housing 3. Function. Therefore, it is possible to prevent fine dust and the like from entering from outside air when the liquid crystal panel is not driven.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

  2 liquid crystal panel module, 3 liquid crystal panel housing, 3f opening hole, 10 air duct, 11 cooling fan, 13 air cleaning filter, 14 pressure sensor, 15 control unit, 16 liquid crystal panel drive circuit.

Claims (5)

A liquid crystal panel module having a liquid crystal panel, a backlight, and a liquid crystal panel housing for housing the liquid crystal panel and the backlight;
A chassis housing disposed on the back side of the liquid crystal panel module;
A liquid crystal panel driving circuit disposed in the chassis housing and driving the liquid crystal panel;
A cooling fan that is disposed in the chassis housing and cools the liquid crystal panel drive circuit by taking outside air into the chassis housing by creating a negative pressure state in the chassis housing;
A filter that is disposed in the chassis housing and filters outside air that passes through the chassis housing and is taken into the cooling fan;
A duct disposed in the chassis casing and separating a part of the exhaust of the cooling fan that has passed through the filter, and fed into the liquid crystal panel casing;
A liquid crystal display device comprising: A pressure sensor that is disposed in the duct and detects the wind pressure of the exhaust gas sent into the liquid crystal panel housing;
The control part which further maintains the inside of the liquid crystal panel case in a predetermined positive pressure state by controlling the number of rotations of the cooling fan based on the wind pressure detected by the pressure sensor. The liquid crystal display device described. The liquid crystal panel housing is provided with an opening hole communicating with the liquid crystal panel housing,
A pressure sensor that is arranged in contact with the periphery of the opening hole outside the liquid crystal panel casing and detects the wind pressure of air flowing out from the liquid crystal panel casing;
The control part which further maintains the inside of the liquid crystal panel case in a predetermined positive pressure state by controlling the number of rotations of the cooling fan based on the wind pressure detected by the pressure sensor. The liquid crystal display device described.   The control unit determines the clogged state of the filter based on the wind pressure detected by the pressure sensor, and recommends replacement of the filter when determining that the filter is clogged. The liquid crystal display device according to claim 2, wherein the information is displayed on a screen of the liquid crystal panel.   The pressure sensor disposed in contact with the peripheral portion of the opening hole functions to close the opening hole when the liquid crystal panel is not driven and to prevent air from entering from outside the liquid crystal panel casing. Item 4. A liquid crystal display device according to Item 3.

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