JP2012032660A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device that efficiently suppresses thermal deformation of a plate like optical member arranged between a liquid crystal panel and an illumination light source that illuminates the liquid crystal panel.SOLUTION: The image display device includes a liquid crystal panel 10; a back light unit 20 arranged at the rear side of the liquid crystal panel 10, and having a light source 22 for illuminating the liquid crystal panel 10; a diffuser plate 31 arranged between the liquid crystal panel 10 and the light source 22; a support section 40b for supporting a peripheral part of the diffuser plate 31 so that the diffuser plate 31 takes a posture in parallel to the liquid crystal panel 10; a cooling device 60 for cooling the back light unit 20; a deformation quantity detection means 70 for detecting a bending quantity of the diffuser plate 31 toward the rear side; and a control circuit board 80 for controlling drive of the light source 22 and/or the cooling device 60 so as to reduce the bending quantity of the diffuser plate 31.

Description

  The present invention relates to an image display device in which a plate-like optical member is disposed between a liquid crystal panel and an illumination light source that illuminates the liquid crystal panel, and in particular, thermal deformation of the optical member can be efficiently suppressed. The present invention relates to an image display device.

  Conventional techniques relating to temperature control performed in an image display device are disclosed in, for example, Patent Documents 1 to 3.

  Patent Document 1 discloses a liquid crystal panel, an illumination device including a fluorescent tube as a light source for illumination, a temperature sensor that detects the ambient temperature of the fluorescent tube, an optical sensor that detects the luminance of the surface of the liquid crystal panel, and an illumination device. And a control circuit for controlling the cooling device according to the detection results from the optical sensor and the temperature sensor, and the maximum brightness can be maintained by controlling the ambient temperature of the fluorescent tube. A liquid crystal display device is disclosed.

  Japanese Patent Application Laid-Open No. 2004-133826 discriminates the number of rotations of a heat radiating fan for cooling the inside of the housing of the display device, an outside air temperature detecting unit for detecting the temperature of the outside air of the display device, and a heat radiating fan corresponding to the detected outside air temperature. And a fan control unit that gradually increases the rotation speed of the heat dissipating fan from non-rotation to the rotation speed determined by the determination section over a predetermined period of time, thereby reducing discomfort due to fan rotation noise. A display device using a PDP (Plasma Display Panel) is disclosed.

  Patent Document 3 discloses a substantially box-shaped main body, a liquid crystal panel and a backlight disposed on the front side of the main body, a control unit disposed on the rear side of the main body, and a first temperature for detecting the temperature of the control unit. A sensor, and when the first temperature sensor detects a temperature equal to or higher than the first set value, the controller may reduce the temperature of the controller to less than the first set value by reducing the input power to the backlight. A possible display device is disclosed.

JP 2000-171773 A JP 2001-227494 A JP 2005-17555 A

  In recent years, liquid crystal display devices have not only been increased in size and brightness, but also have a narrow frame. In such a liquid crystal display device, the plate-like optical member disposed between the liquid crystal panel and the illumination light source that illuminates the liquid crystal panel is thermally deformed to an unacceptable level due to the heat generated by the illumination light source. This causes a problem that the image quality of the image displayed on the liquid crystal panel is deteriorated.

  None of the above Patent Documents 1 to 3 is configured to perform temperature control by paying attention to thermal deformation of the optical member. Therefore, image quality deterioration due to thermal deformation of the optical member cannot be efficiently suppressed, and therefore there is a problem that noise due to the cooling device cannot be reduced.

  Moreover, in the said patent documents 1-3, since it is comprised so that only one of a cooling device and the light source for illumination may be controlled, there exists a problem that efficient and highly accurate control cannot be performed.

  An object of the present invention is to provide an image display device capable of efficiently suppressing thermal deformation of a plate-like optical member disposed between a liquid crystal panel and an illumination light source that illuminates the liquid crystal panel. is there.

The present invention provides a liquid crystal panel capable of displaying an image,
An illuminating device that is disposed on the back side of the liquid crystal panel and includes an illumination light source that illuminates the liquid crystal panel;
A plate-like member disposed between the liquid crystal panel and the illumination light source, and made of a diffusion plate or a reinforcing plate;
A support portion for supporting the peripheral portion of the plate-like member so that the plate-like member is in a parallel or substantially parallel posture with respect to the liquid crystal panel;
A cooling device for cooling the lighting device;
Deformation amount detection means for detecting the amount of extension in the surface direction of the plate-shaped member or the amount of deflection of the plate-shaped member toward the back surface;
Control means for controlling the driving of the illumination light source and / or the cooling device so as to reduce the amount of extension or deflection based on the detection result output from the deformation amount detection means. An image display device.

In the present invention, the deformation amount detecting means includes:
A displacement member provided on the back side of the plate-like member, supported at a predetermined initial position, and displaceable in a direction approaching / separating from the plate-like member;
A displacement amount detector that detects a displacement amount from an initial position of the displacement member,
The control unit controls driving of the illumination device and / or the cooling device so that the displacement member returns to an initial position based on a detection result output from the displacement amount detection unit. To do.

  In the invention, it is preferable that the displacement amount detection unit includes a light detection unit that optically detects a displacement amount from an initial position of the displacement member.

The deformation amount detecting means further includes a deformation member that deforms according to a displacement amount from an initial position of the displacement member,
The displacement amount detection unit includes a strain detection unit that detects a strain amount of the deformable member.

In the present invention, the deformation amount detecting means includes:
On the back side of the plate-like member, provided fixed at a position spaced from the plate-like member, including a distance measuring unit that detects the distance to the plate-like member in a non-contact manner,
The control unit controls driving of the lighting device and / or the cooling device so that a distance to the plate-like member is larger than a predetermined distance based on a detection result output from the distance measuring unit. It is characterized by doing.

In the present invention, the deformation amount detecting means includes:
A displacement member provided on the back side of the plate-like member so as to be displaceable in a direction approaching / separating from the plate-like member;
A switch element capable of switching between a conduction state and a cutoff state in accordance with the displacement of the displacement member;
The control unit controls driving of the lighting device and / or the cooling device so that the displacement member returns to an initial position based on a state of the switch element.

In the present invention, the deformation amount detecting means includes:
A switch element that is provided on the outer side in the surface direction of the plate-like member, and that can switch between a conductive state and a cut-off state as the plate-like member extends in the surface direction;
The control unit controls the driving of the lighting device and / or the cooling device so that the extension in the surface direction of the plate-like member is reduced based on the state of the switch element.

  According to the present invention, since the cooling device drive control is performed by detecting the deformation amount of the diffusion plate or the reinforcing plate, it is possible to efficiently prevent image quality deterioration when the temperature of the image display device rises, Noise associated with driving of the cooling device can be reduced as much as possible to reduce noise. In addition, since the deformation amount of the diffusion plate or the reinforcing plate is efficiently detected from the initial stage where the deformation amount of the diffusion plate or the reinforcing plate is relatively small, the image quality deterioration due to the temperature rise in the image display device does not occur / progress. On the side, the driving of the cooling device and / or the lighting of the illumination light source can be controlled.

1 is a cross-sectional view illustrating a schematic configuration of a liquid crystal display device 100 according to a first embodiment of the present invention. It is a front view in the use condition of the liquid crystal display device 100 which concerns on 1st Embodiment of this invention. It is a figure which shows an example of arrangement | positioning of the 1st and 2nd protrusion members 51 and 52 on the inner surface of the baseplate 21a. It is a figure which shows another example of arrangement | positioning of the 1st and 2nd protrusion members 51 and 52 on the inner surface of the baseplate 21a. 4 is a cross-sectional view showing an operating state of the liquid crystal display device 100. FIG. 6 is a cross-sectional view showing the liquid crystal display device 100 when the arrangement positions of the photointerrupters P1 to P3 in the Z2 direction are changed for each deformation amount detection element 70. FIG. 2 is a block diagram showing an electrical configuration of a liquid crystal display device 100. FIG. 4 is a flowchart of drive control in the liquid crystal display device 100 according to the first embodiment of the present invention. It is sectional drawing which shows schematic structure of the liquid crystal display device 200 which concerns on 2nd Embodiment of this invention. It is a flowchart of the drive control in the liquid crystal display device 200 which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows schematic structure of the liquid crystal display device 300 which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows schematic structure of the liquid crystal display device 400 which concerns on 4th Embodiment of this invention. It is a flowchart of the drive control in the liquid crystal display device 400 which concerns on 4th Embodiment of this invention. It is sectional drawing which shows schematic structure of the liquid crystal display device 500 which concerns on 5th Embodiment of this invention.

  FIG. 1 is a cross-sectional view showing a schematic configuration of a liquid crystal display device 100 according to the first embodiment of the present invention. FIG. 2 is a front view of the liquid crystal display device 100 according to the first embodiment of the present invention in use. 1 corresponds to a cross-sectional view taken along the section line II shown in FIG.

  A liquid crystal display device 100 that is an image display device includes a liquid crystal panel 10 that is a non-luminous display panel capable of displaying an image, and a light source 22 that is disposed on the back side of the liquid crystal panel 10 and illuminates the liquid crystal panel 10. The backlight unit 20 provided, the optical member 30 disposed between the liquid crystal panel 10 and the light source 22, the frame 40 that supports the optical member 30, and the protrusion that restricts the deformation of the optical member 30 toward the back side. Unit 50, cooling device 60 for cooling backlight unit 20, deformation amount detection element 70 for detecting the deformation amount of optical member 30, and optical member 30 based on the detection result output from deformation amount detection element 70. The control circuit board 80 on which a control circuit for controlling the driving of the light source 22 and the cooling device 60, the liquid crystal panel 10 and the backlight unit are mounted. The Tsu bets 20 and a frame-shaped bezel 90 that integrally holds.

  As shown in FIG. 2, the liquid crystal display device 100 is used in such a posture that the short side direction of the liquid crystal panel 10 and the vertical direction coincide with each other, and is supported by a stand ST, for example. Here, the direction indicated by the arrow X in the figure is a direction parallel to the short side direction of the liquid crystal panel 10, the direction indicated by the arrow Y is a direction parallel to the long side direction of the liquid crystal panel 10, The direction indicated by the symbol Z is a direction parallel to the depth direction of the liquid crystal display device 100, and the short side direction X, the long side direction Y, and the depth direction Z are directions orthogonal to each other.

  In the description of the embodiment, the front side is the side on which the liquid crystal panel 10 is arranged when the liquid crystal display device 100 is viewed in the depth direction Z, that is, the side facing the direction indicated by the arrow Z1, and the back side. The side is the side where the backlight unit 20 is disposed when the liquid crystal display device 100 is viewed in the depth direction Z, that is, the side facing the direction indicated by the arrow Z2.

Hereinafter, each configuration of the liquid crystal display device 100 will be described.
The liquid crystal panel 10 encloses a pair of translucent glass substrates formed in a horizontally long rectangular shape, and liquid crystal molecules that are substances whose optical characteristics change with application of an electric field between the pair of substrates. And a pair of substrates are bonded together with a sealant in a state where a gap corresponding to the thickness of the liquid crystal layer is maintained. When the size of the display screen of the liquid crystal display device 100 is 60 inches, the rectangular liquid crystal panel 10 has a short side dimension of about 750 mm and a long side dimension of about 1300 mm.

  Of the pair of substrates, one substrate is a CF (Color Filter) substrate, and the other substrate is a TFT (Thin Film Transistor) substrate. The TFT substrate is provided with a large number of TFTs and pixel electrodes, which are switching elements, arranged side by side on the inner surface facing the liquid crystal layer, and around these TFTs and pixel electrodes, gate wirings and source wirings forming a lattice shape are provided. It is arranged so as to surround it. The pixel electrode is made of a transparent electrode such as ITO (Indium Tin Oxide) or ZnO (Zinc Oxide).

  On the other hand, on the inner surface side facing the liquid crystal layer, a large number of color filters are arranged side by side on the CF substrate at positions corresponding to the respective pixels. The color filter is arranged so that subpixels of three colors of R (red), G (green), and B (blue) are alternately arranged. A light shielding layer (black matrix) for preventing color mixture is formed between the color filters. A counter electrode facing the pixel electrode on the TFT substrate side is provided on the surface of the color filter and the light shielding layer. In addition, an alignment film for aligning liquid crystal molecules contained in the liquid crystal layer is formed on the inner surface side of each substrate, and a polarizing plate is pasted on the outer surface side opposite to the inner surface side of each substrate. It is attached.

  A backlight unit 20 that is a lighting device includes a backlight chassis 21 that is formed in a substantially box shape that is open on one side, a light source 22 that is housed in the backlight chassis 21, and a backlight chassis 21 that is laid in the backlight chassis 21 (not shown). A reflection sheet. As shown in FIG. 1, the backlight unit 20 according to the present embodiment is configured as a so-called direct-type backlight in which a light source 22 is disposed immediately below the back surface of the liquid crystal panel 10.

  The backlight chassis 21 is made of metal, and includes a bottom plate 21a formed in a horizontally long rectangular shape similar to the liquid crystal panel 10, and a side plate 21b rising from the peripheral edge of the bottom plate 21a. Thereby, the backlight chassis 21 is formed in the substantially box shape opened to one side. Hereinafter, the inner surface of the backlight chassis 21 is a surface facing the accommodation space S surrounded by the bottom plate 21a and the side plate 21b, and the outer surface is a surface opposite to the inner surface and facing outward. It is.

  The light source 22, which is an illumination light source, is installed on the inner surface of the bottom plate 21 a in the backlight chassis 21 and emits light to illuminate the liquid crystal panel 10. In the present embodiment, the light source 22 is configured by arranging a plurality of LED (Light Emitting Diode) lamps in a matrix on the inner surface of the bottom plate 21a. In another embodiment, the light source 22 may be configured, for example, by arranging a plurality of cold-cathode tubes on the inner surface of the bottom plate 21a in parallel at a predetermined interval.

  The reflection sheet is made of a synthetic resin exhibiting white with excellent light reflectivity, and is laid so as to cover the inner surface of the bottom plate 21a in the backlight chassis 21 and the inner surface of the frame 40 attached to the side plate 21b. With this reflection sheet, most of the light emitted from the light source 22 can be guided to the opening side of the backlight chassis 21. In another embodiment, instead of providing the reflection sheet, a portion to be covered with the reflection sheet may be made of a resin or metal excellent in light reflectivity. Thereby, a reflective sheet can be abbreviate | omitted and a number of parts can be reduced.

  The optical member 30 is laminated on a plate-like member 31 formed in a horizontally long rectangular shape similar to that of the liquid crystal panel 10 and one surface in the thickness direction of the plate-like member 31 and is composed of one or more sheet-like members. And an optical sheet 32. In the present embodiment, a diffuser plate having a function of diffusing light emitted from the light source 22 in the surface direction is used as the plate-like member 31.

  In another embodiment, a light-transmitting reinforcing plate may be used as the plate-like member 31 instead of a diffusion plate. The reinforcing plate is, for example, a plate-like member that is used to suppress the bending of the optical sheet 32 when the light source 22 and the liquid crystal panel 10 are sufficiently separated from each other and the diffusion plate is unnecessary. . Alternatively, it is a plate-like member that is used in the vicinity of the liquid crystal panel 10 when it is desired to suppress the bending of the liquid crystal panel 10 caused by the external force applied to the back side within a predetermined amount of bending. Alternatively, when the thickness of the diffusion plate is made thinner than a normal thickness for cost reduction, it is a plate-like member used by being arranged on both sides of the diffusion plate in the thickness direction in order to reinforce the diffusion plate .

As the material of the plate-like member 31, for example, acrylic resin, polystyrene, and polycarbonate are preferably used. The linear expansion coefficient of the plate-like member 31 made of these materials is about 7 × 10 ⁻⁵ / ° C.

  The thickness of the plate-like member 31 is determined based on the size of the display screen of the liquid crystal display device 100. For example, when the size of the display screen is 32 inches, the thickness is determined to be about 1.5 mm. When the display screen size is 60 inches, the thickness is determined to be about 2.5 mm, and when the display screen size is 100 inches, the thickness is determined to be about 4 mm. In the following description, the plate member 31 is referred to as a diffusion plate 31. The optical sheet 32 is formed by laminating, for example, a diffusion sheet, a lens sheet, and a polarization-type brightness enhancement film in order from the diffusion plate 31 side.

  The frame 40 is made of resin, is generally cylindrical, and is formed in a shape that covers the inner surface of the side plate 21 b in the backlight chassis 21. The frame 40 is attached to the side plate 21b and is fixed to the side plate 21b by a fastener such as a screw.

  The frame 40 has a support portion 40a for supporting the liquid crystal panel 10 in an opening on the side opposite to the opening on the side adjacent to the bottom plate 21a when mounted on the side plate 21b. Furthermore, the frame 40 includes a support portion 40b for supporting the optical member 30 and a side wall portion 40c connected to the support portion 40b at an intermediate portion between both openings.

  The support portion 40 a has a rectangular annular flat support surface for supporting the liquid crystal panel 10. The support surface is formed to be parallel or substantially parallel to the inner surface of the bottom plate 21a in the backlight chassis 21 when the frame 40 is mounted on the side plate 21b.

  The liquid crystal panel 10 is installed on the support portion 40a so that the TFT substrate is in surface contact with the support surface. Accordingly, the liquid crystal panel 10 is supported by the support portion 40a in a posture that is parallel or substantially parallel to the inner surface of the bottom plate 21a. At this time, the support portion 40 a supports the peripheral edge portion of the liquid crystal panel 10. The liquid crystal panel 10 supported by the support portion 40a is fixed by being sandwiched from both sides in the thickness direction by the support portion 40a and the bezel 90.

  The support portion 40 b has a rectangular annular flat support surface for supporting the optical member 30. The support surface is formed to be parallel or substantially parallel to the inner surface of the bottom plate 21a in the backlight chassis 21 when the frame 40 is mounted on the side plate 21b.

  The optical member 30 is installed on the support portion 40b so that the diffusion plate 31 is in surface contact with the support surface. Accordingly, the optical member 30 is supported by the support portion 40b in a posture that is parallel or substantially parallel to the inner surface of the bottom plate 21a. At this time, the support portion 40 b supports the peripheral edge portion of the diffusion plate 31.

  The side wall portion 40c has an inner wall surface that rises vertically from the outer peripheral edge of the support surface of the support portion 40b. In the liquid crystal display device 100 according to the present embodiment, the side wall portion 40c is formed between the outer edge portion of the optical member 30 installed on the support portion 40b and the inner wall surface in order to realize a large and narrow frame. The gap is designed to have a dimension that is insufficient to allow the optical member 30 to extend in the surface direction due to thermal expansion that occurs during operation of the liquid crystal display device 100, for example, 1 mm or less.

  In the present embodiment, the optical member 30 has a plurality of engaging protrusions protruding in the surface direction on the outer periphery thereof, and the side wall portion 40c has the optical member 30 installed on the support portion 40b. An engagement hole for fitting the engagement protrusion is formed in a portion where the engagement protrusion is disposed. The optical member 30 is attached to the frame 40 by fitting the engagement protrusion into the engagement hole, and thereby the displacement of the support portion 40b in the direction away from the support surface is restricted.

  The liquid crystal display device 100 operates using electric power as a driving force when electric power is supplied from a power source. In the operating state, light is emitted from the light source 22 by supplying power to the light source 22. Of the light emitted from the light source 22, the linearly polarized light transmitted through the polarizing plate provided on the back side of the liquid crystal panel 10 passes through the liquid crystal layer and enters the polarizing plate provided on the front side of the liquid crystal panel 10. . At this time, the polarization state of light transmitted through the liquid crystal layer can be changed by an electric field applied to the liquid crystal layer. Therefore, a voltage corresponding to the image information input to the liquid crystal display device 100 is applied to the pixel electrode of the CF substrate and the counter electrode of the TFT substrate, and an electric field is applied to the liquid crystal layer, so that the light passing through the liquid crystal layer is transmitted. The amount of light transmitted through the polarizing plate can be controlled by changing the polarization state. Thereby, an optical image based on the image information input to the liquid crystal display device 100 can be displayed on the liquid crystal panel 10.

  In the liquid crystal display device 100, in the operation state, the temperature of each member provided around the light source 22 and the gas around the light source 22 rises due to heat generated by the light source 22 that emits light. Therefore, in the operating state of the liquid crystal display device 100, thermal expansion due to a temperature rise occurs in the optical member 30 provided to face the light source 22. For example, in the optical member 30 mounted on the liquid crystal display device 100 having a display screen size of 60 inches, when the temperature rises from room temperature to 50 ° C., the long side direction Y extends by about 4.7 mm. Arise.

  However, in the liquid crystal display device 100, as described above, a gap formed between the outer edge portion of the optical member 30 installed on the support portion 40b and the inner wall surface of the side wall portion 40c is caused by thermal expansion of the optical member 30. It is not designed to be dimensioned to allow elongation in the surface direction. Therefore, in the liquid crystal display device 100, the optical member 30 is deformed by bending as the temperature inside the device rises. More specifically, in the optical member 30, the side facing the light source 22 has a higher temperature than the side facing the liquid crystal panel 10, and hence the amount of elongation in the surface direction is also large. Will be deformed by bending so as to be convex toward the back side. When the amount of deflection toward the back side increases, the function as the optical member 30 cannot be fully exerted, and the quality of the display image deteriorates, such as uneven brightness.

  Therefore, the liquid crystal display device 100 is provided with a protruding portion 50 that restricts the deformation of the optical member 30 toward the back side. Specifically, the protruding portion 50 is a first protruding member 51 that stands vertically from the inner surface of the bottom plate 21a toward the optical member 30 in the backlight chassis 21 and has different heights from the inner surface of the bottom plate 21a. The second projecting member 52 is configured. The material of the first and second projecting members 51 and 52 is, for example, polycarbonate having a high reflectance.

  The first protruding member 51 is formed such that the height from the inner surface of the bottom plate 21a is a predetermined height h1. Here, the predetermined height h1 is a height at which the tip of the first projecting member 51 comes into contact with the optical member 30 at normal temperature supported by the support portion 40b, or optical at normal temperature. The height is set so as to be slightly separated from the member 30. Here, the optical member 30 at normal temperature is the optical member 30 before the thermal deformation caused by the operation of the liquid crystal display device 100 occurs.

  The second projecting member 52 is formed such that the height from the inner surface of the bottom plate 21a is a predetermined height h2. Here, the predetermined height h2 is lower than the predetermined height h1, and the tip of the second projecting member 52 is the maximum allowable with respect to the optical member 30 at normal temperature supported by the support portion 40b. The height is set so as to be separated by a deflection amount. Here, the maximum allowable deflection amount is a deflection amount to the back side of the optical member 30 and is a maximum value in a numerical range set in advance as a deflection amount capable of displaying an image without deteriorating the image quality. is there.

  The projecting portion 50 is formed by appropriately arranging a plurality of such first and second projecting members 51 and 52 on the inner surface of the bottom plate 21a, so that the optical member 30 is flexibly deformed toward the back side. Can be regulated. FIG. 3 is a view showing an example of the arrangement of the first and second projecting members 51 and 52 on the inner surface of the bottom plate 21a, and shows a view when viewed from the front side. FIG. 4 is a view showing another example of the arrangement of the first and second projecting members 51 and 52 on the inner surface of the bottom plate 21a, and shows a view when seen from the front side. 3 and 4, the position where the first projecting member 51 is disposed is indicated by a triangular mark, and the position where the second projecting member 52 is disposed is indicated by a circle.

  In the arrangement example of FIG. 3, the first and second projecting members 51 and 52 are arranged in a matrix, and the first projecting member 51 and the second projecting member 52 are arranged in the row direction and the column direction. Alternatingly arranged. Further, in the arrangement example of FIG. 4, the first and second projecting members 51 and 52 are disposed radially from the center in the surface direction, and further, the first projecting member 51 and the second projecting member 52. Are alternately arranged in the radial direction.

  FIG. 5 is a cross-sectional view showing an operating state of the liquid crystal display device 100. As described above, the first protruding member 51 having the predetermined height h1 and the second protruding member 52 having the predetermined height h2 are alternately provided, so that the optical member 30 is bent into a wave shape. The second projecting member 52 restricts the portion of the optical member 30 that faces the tip of the second projecting member 52 from being displaced toward the light source 22 from the tip of the second projecting member 52. Thereby, it is possible to prevent the optical member 30 from being bent beyond the maximum allowable bending amount.

  The cooling device 60 is a device for cooling the backlight unit 20 and is mounted on the back side of the backlight chassis 21. In the present embodiment, the cooling device 60 is constituted by a cooling fan. In the following description, the cooling device 60 is referred to as a cooling fan 60.

  The deformation amount detection element 70 is configured to detect the deformation amount of the optical member 30. In the present embodiment, the deformation amount detection element 70 is configured to detect the amount of deflection of the optical member 30 toward the back surface, and the second protrusion. It is provided at a position close to the position where the member 52 is erected. As a result, the deformation amount detecting element 70 can be used to efficiently detect the deflection amount of the diffusion plate 31 from the initial stage where the deflection amount of the diffusion plate 31 toward the back surface is relatively small. When a plurality of deformation amount detection elements 70 are provided, each of the second protrusion members 52 is provided. Moreover, in other embodiment, it may replace with the 2nd protrusion member 52 in the position in which the 2nd protrusion member 52 shown in FIG.3 and FIG.4 is provided.

  Specifically, the deformation amount detecting element 70 is supported at an initial position on the back side of the optical member 30 and separated by a predetermined distance from the optical member 30 at normal temperature supported by the support portion 40b. In addition, a displacement member 71 provided so as to be displaceable in the direction of approaching / separating from the optical member 30, that is, the depth direction Z, and a displacement amount detection unit that detects a displacement amount in the Z2 direction from the initial position of the displacement member 71 72, and a tension coil spring 73 that biases the displacement member 71 in the direction close to the optical member 30, that is, the Z1 direction.

  The displacement member 71 is generally formed in a rod shape, and is formed of the same material as that of the first and second projecting members 51 and 52, for example. The displacement member 71 is inserted through a through-hole formed in the bottom plate 21a of the backlight chassis 21, and the displacement member 71 is disposed in the Z1 direction between the detection side end disposed on the back side of the bottom plate 21a and the bottom plate 21a. A tension coil spring 73 is attached so as to be biased. The tension coil spring 73 supports the displacement member 71 so that the displacement member 71 maintains the initial position.

  The initial position is determined such that the tip of the contact side end disposed on the front side of the bottom plate 21 a of the displacement member 71 is disposed on the front side of the tip of the second projecting member 52. . For example, the front end of the contact side end is determined at a position where it is disposed at the same height as the front end of the first projecting member 51.

  The displacement amount detection unit 72 includes a plurality of photointerrupters P1 to P3 that are light detection units that detect the displacement amount of the displacement member 71 from the initial position. Each of the photo interrupters P1 to P3 is installed at a position facing the passing region through which the tip of the detection side end of the displacement member 71 passes along with the displacement of the displacement member 71 from the initial position in the Z2 direction. Are installed at different positions.

  For example, the photo interrupters P1 to P3 are installed at positions spaced α, β, and γ (where α <β <γ) in the Z2 direction from the tip of the detection side end of the displacement member 71 at the initial position. . Thereby, the displacement amount detection unit 72 can detect that the displacement amounts from the initial position of the displacement member 71 have reached α, β, and γ. That is, the displacement amount detection unit 72 is configured to detect the displacement amount of the displacement member 71 from the initial position in a stepwise manner. The displacement amount detection unit 72 outputs detection results by the photo interrupters P <b> 1 to P <b> 3 to the control circuit board 80.

  In addition, when using a plurality of photo interrupters P1 to P3, instead of arranging all the photo interrupters P1 to P3 in one deformation amount detecting element 70, the photo interrupters P1 to P1 are dispersed in the plurality of deformation amount detecting elements 70. P3 may be arranged, and the arrangement positions of the photo interrupters P1 to P3 in the Z2 direction may be made different for each deformation amount detection element 70. FIG. 6 is a cross-sectional view showing the liquid crystal display device 100 when the arrangement positions of the photo interrupters P1 to P3 in the Z2 direction are different for each deformation amount detection element 70. At the position where the second projecting member 52 is disposed, the amount of deflection of the diffuser plate 31 occurs at any position. Therefore, even when the amount of deflection of the diffuser plate 31 increases, the diffuser plate is moved by the photo interrupter at a different position. The amount of deflection of 31 can be detected stepwise.

  The control circuit board 80 is mounted on the back side of the backlight chassis 21 and includes a control circuit for controlling the driving of the light source 22 and the cooling fan 60.

  FIG. 7 is a block diagram showing an electrical configuration of the liquid crystal display device 100. The liquid crystal display device 100 includes a deformation amount detection element 60 that detects the deformation amount of the diffusion plate 31, a control circuit board 80, a control circuit 80a to which a detection result by the deformation amount detection element 70 is input, and a detection result. Accordingly, the light source 22 and the cooling fan 60 are controlled by the control circuit 80a.

  The control circuit 80a includes a CPU (Central Processing Unit) 81, a storage unit 82, a determination unit 83, a cooling device control unit 84, a DAC (Digital to Analog Converter) 85, a light source control unit 86, and a DAC 87. Consists of including.

  The CPU 81 controls the determination unit 83, the cooling device control unit 84, and the light source control unit 86 in accordance with a program stored in the storage unit 82.

  The storage unit 82 stores data on the duty ratio of the supply voltage to the cooling fan 60 and the duty ratio of the supply voltage to the light source 22 set in advance corresponding to the deformation amount of the diffusion plate 31.

  The determining unit 83 determines the duty ratio of the supply voltage to the cooling fan 60 and the light source 22 corresponding to the detection result of the deformation amount output from the deformation amount detecting element 70 based on the data stored in the storage unit 82. To do.

  The cooling device control unit 84 controls the start and stop of a variable rotation speed type cooling fan motor for rotationally driving the fan included in the cooling fan 60 according to a command from the CPU 81, and the cooling fan motor A control signal for controlling the duty ratio of the supply voltage to the cooling fan motor during driving is output to the DAC 85.

  The DAC 85 converts the control signal input from the cooling device control unit 84 into an analog voltage and outputs the analog voltage to the cooling fan 60.

  The light source controller 86 outputs, to the DAC 87, a control signal for controlling turning on and off of the light source 22 and a control signal for controlling the duty ratio of the voltage supplied to the light source 22 when the light source 22 is turned on in accordance with a command from the CPU 81. To do.

  The DAC 87 converts the control signal input from the light source control unit 86 into an analog voltage and outputs the analog voltage to the light source 22.

  FIG. 8 is a flowchart of drive control in the liquid crystal display device 100 according to the first embodiment of the present invention. This control flow is based on the premise that the liquid crystal display device 100 is always used in an operating state. Unless the temperature abnormality occurs in the liquid crystal display device 100 and the control is stopped, the liquid crystal display device 100 is not stopped.

  In step s1, the occurrence of a power ON occurrence or a return request (signal input) from a standby state (power saving mode or screen saver) is monitored. In step s2, the light source 22 is normally lit at a preset duty ratio. In step s3, a standby for a predetermined time, for example, 10 seconds is executed.

  In step s4, it is determined whether or not the photo interrupter P1 has detected the displacement member 71. If detected, the process proceeds to step s5, and if not detected, the process proceeds to step s12. In step s5, the cooling fan 60 is driven at a duty ratio of 50%. In step s6, it is determined whether the photo interrupter P2 has detected the displacement member 71. If detected, the process proceeds to step s7, and if not detected, the process proceeds to step s14.

  In step s7, the cooling fan 60 is driven at a duty ratio of 100%. In step s8, it is determined whether or not the photo interrupter P3 has detected the displacement member 71. If detected, the process proceeds to step s9, and if not detected, the process proceeds to step s15.

  In step s9, the duty ratio of the light source 22 is reset to 80% of the current value. In step s10, it is determined whether or not the duty ratio of the reset light source 22 exceeds 30% with respect to the full duty. If it exceeds, the process proceeds to step s11, and if not, the process proceeds to step s16. move on.

  In step s11, standby is performed for a predetermined time, for example, 5 minutes. Then, the process proceeds to step s8. In step s12, the driving of the cooling fan 60 is stopped. In step s13, standby is performed for a predetermined time, for example, 3 minutes. Then, the process proceeds to step s4.

  In step s14, the light source 22 is normally lit at a preset duty ratio. Then, the process proceeds to step s13. In step s15, standby is performed for a predetermined time, for example, 3 minutes. Then, the process proceeds to step s6. In step s16, it is assumed that a temperature abnormality has occurred in the liquid crystal display device 100, the temperature abnormality notification / notification is performed, and the control of the liquid crystal display device 100 is stopped.

  As described above, according to the present embodiment, the cooling fan 60 is controlled by detecting the amount of displacement of the diffusion plate 31, that is, the amount of deflection toward the back side, so that the temperature of the liquid crystal display device 100 is increased. Degradation of the image quality can be efficiently prevented, and noise associated with driving of the cooling fan 60 can be reduced as much as possible.

  Further, the first and second projecting members 51 and 52 and the deformation amount detecting element 70 efficiently detect the amount of deflection of the diffusion plate 31 from the initial stage where the amount of deflection of the diffusion plate 31 toward the back surface is relatively small. Therefore, the driving of the cooling fan 60 and the lighting of the light source 22 can be controlled on the safe side where the image quality deterioration due to the temperature rise in the liquid crystal display device 100 does not occur / progress.

  FIG. 9 is a cross-sectional view showing a schematic configuration of a liquid crystal display device 200 according to the second embodiment of the present invention. Since the liquid crystal display device 200 according to the present embodiment is configured substantially the same as the liquid crystal display device 100 according to the first embodiment with respect to the remaining configuration except for the configuration of the deformation amount detection element 70, the corresponding portions are not described. Are given the same reference numerals, and redundant explanations are omitted.

  The deformation amount detection element 70 is configured to detect the deformation amount of the optical member 30. In the present embodiment, the deformation amount detection element 70 is configured to detect the amount of deflection of the optical member 30 toward the back surface, and the second protrusion. It is provided at a position close to the position where the member 52 is erected. As a result, the deformation amount detecting element 70 can be used to efficiently detect the deflection amount of the diffusion plate 31 from the initial stage where the deflection amount of the diffusion plate 31 toward the back surface is relatively small.

  Specifically, the deformation amount detecting element 70 is supported at an initial position on the back side of the optical member 30 and separated by a predetermined distance from the optical member 30 at normal temperature supported by the support portion 40b. In addition, a displacement member 171 that is displaceable in the direction of approaching / separating from the optical member 30, that is, the depth direction Z, and a deformation member 172 that deforms due to bending according to the amount of displacement from the initial position of the displacement member 171. And a strain detector 173 that detects the amount of strain associated with the deformation caused by the deformation of the deformable member 172.

  The displacement member 171 is generally formed in a rod shape, and is formed of the same material as that of the first and second projecting members 51 and 52, for example. The displacement member 171 is inserted through a through-hole formed in the bottom plate 21a of the backlight chassis 21, and the detection side end arranged on the back side of the bottom plate 21a is cantilevered on the back side of the bottom plate 21a. The deformation member 172 is fixed to the free end portion.

  The deformable member 172 is a plate-like member, and a base end portion that is an end portion on one side in the longitudinal direction is fixed to the outer surface of the bottom plate 21a using a fastener such as a screw, and the other end portion in the longitudinal direction is fixed. The detection side end of the displacement member 171 is fixed to the free end that is the end, and the free end is provided so as to be displaceable in the Z2 direction with respect to the base end. The deformation member 172 supports the displacement member 171 so that the displacement member 171 maintains the initial position.

  The initial position is determined such that the tip of the contact side end disposed on the front side of the bottom plate 21 a of the displacement member 171 is disposed on the front side of the tip of the second protruding member 52. . For example, the front end of the contact side end is determined at a position where it is disposed at the same height as the front end of the first projecting member 51.

  The strain detection unit 173 is configured by a strain gauge that can detect the amount of strain accompanying deformation due to the deformation of the deformation member 172. The strain detection unit 173 is attached between the base end portion and the free end portion of the deformation member 172. The strain detection unit 173 is configured to continuously detect the amount of displacement of the displacement member 171 from the initial position. The distortion detection unit 173 outputs the detection result to the control circuit board 80.

  FIG. 10 is a flowchart of drive control in the liquid crystal display device 200 according to the second embodiment of the present invention. This control flow is based on the premise that the liquid crystal display device 200 is always used in an operating state. Unless the temperature abnormality occurs in the liquid crystal display device 200 and the control is stopped, the liquid crystal display device 200 is not stopped. As described above, the displacement amount of the displacement member 171 itself is continuously detected, but the output level determination criteria (threshold setting for controlling the liquid crystal display device 200) are, for example, three levels A to C. Set to

  In step a1, the occurrence of a power ON occurrence or a return request (signal input) from a standby state (power saving mode or screen saver) is monitored. In step a2, the light source 22 is normally lit at a preset duty ratio. In step a3, a standby for a predetermined time, for example, 10 seconds is executed.

  In step a4, it is determined whether or not the output level from the distortion detector 173 has become smaller than level A. If it has become smaller, the process proceeds to step a5, and if not, the process proceeds to step a12. In step a5, the cooling fan 60 is driven at a duty ratio of 50%. In step a6, it is determined whether or not the output level from the distortion detector 173 has become smaller than level B. If it has become smaller, the process proceeds to step a7, and if not, the process proceeds to step a14.

  In step a7, the cooling fan 60 is driven at a duty ratio of 100%. In step a8, it is determined whether or not the output level from the distortion detector 173 has become smaller than level C. If it has become smaller, the process proceeds to step a9, and if not, the process proceeds to step a15.

  In step a9, the duty ratio of the light source 22 is reset to 80% of the current value. In step a10, it is determined whether or not the duty ratio of the reset light source 22 exceeds 30% with respect to the full duty. If it exceeds, the process proceeds to step a11. If not, the process proceeds to step a16. move on.

  In step a11, standby is performed for a predetermined time, for example, 5 minutes. Then, the process proceeds to step a8. In step a12, the driving of the cooling fan 60 is stopped. In step a13, a standby for a predetermined time, for example, 3 minutes is executed. Then, the process proceeds to step a4.

  In step a14, the light source 22 is normally lit at a preset duty ratio. Then, the process proceeds to Step a13. In step a15, a standby is performed for a predetermined time, for example, 3 minutes. Then, the process proceeds to step a6. In step a16, it is assumed that a temperature abnormality has occurred in the liquid crystal display device 200, the temperature abnormality notification / notification is performed, and the control of the liquid crystal display device 200 is stopped.

  As described above, according to the present embodiment, the cooling fan 60 is controlled by detecting the amount of displacement of the diffusion plate 31, that is, the amount of deflection toward the back side, so that when the temperature of the liquid crystal display device 200 increases. Degradation of the image quality can be efficiently prevented, and noise associated with driving of the cooling fan 60 can be reduced as much as possible.

  Further, the first and second projecting members 51 and 52 and the deformation amount detecting element 70 efficiently detect the amount of deflection of the diffusion plate 31 from the initial stage where the amount of deflection of the diffusion plate 31 toward the back surface is relatively small. Therefore, the driving of the cooling fan 60 and the lighting of the light source 22 can be controlled on the safe side where the image quality deterioration due to the temperature rise in the liquid crystal display device 200 does not occur / progress.

  FIG. 11 is a cross-sectional view showing a schematic configuration of a liquid crystal display device 300 according to the third embodiment of the present invention. Since the liquid crystal display device 300 according to the present embodiment is configured substantially the same as the liquid crystal display device 100 according to the first embodiment with respect to the remaining configuration except for the configuration of the deformation amount detection element 70, the corresponding parts are not described. Are given the same reference numerals, and redundant explanations are omitted.

  The deformation amount detection element 70 is configured to detect the deformation amount of the optical member 30. In the present embodiment, the deformation amount detection element 70 is configured to detect the amount of deflection of the optical member 30 toward the back surface in a non-contact manner. It is provided at a position close to the position where the two protruding members 52 are erected. As a result, the deformation amount detecting element 70 can be used to efficiently detect the deflection amount of the diffusion plate 31 from the initial stage where the deflection amount of the diffusion plate 31 toward the back surface is relatively small.

  Specifically, the deformation amount detection element 70 includes a distance measurement unit 271 that is provided on the back side of the optical member 30 and fixed to the bottom plate 21 a that is spaced from the optical member 30. The distance measuring unit 271 includes a light emitting element and a light receiving element, and is configured to be able to detect the distance to the optical member 30 in a non-contact manner. The distance measuring unit 271 can continuously detect the amount of deflection of the optical member 30 toward the back side by measuring the distance to the optical member 30. The distance measuring unit 271 outputs the detection result to the control circuit board 80. In the present embodiment, drive control is performed according to the control flow shown in FIG.

  As described above, according to the present embodiment, the cooling fan 60 is controlled by detecting the amount of displacement of the diffusion plate 31, that is, the amount of deflection toward the back side, so that when the temperature of the liquid crystal display device 300 increases. Degradation of the image quality can be efficiently prevented, and noise associated with driving of the cooling fan 60 can be reduced as much as possible.

  Further, the first and second projecting members 51 and 52 and the deformation amount detecting element 70 efficiently detect the amount of deflection of the diffusion plate 31 from the initial stage where the amount of deflection of the diffusion plate 31 toward the back surface is relatively small. Therefore, the driving of the cooling fan 60 and the lighting of the light source 22 can be controlled on the safe side where the image quality deterioration due to the temperature rise in the liquid crystal display device 200 does not occur / progress.

  In addition, since the amount of deflection of the diffusion plate 31 toward the back surface can be detected in a non-contact manner, the apparatus configuration can be simplified.

  FIG. 12 is a cross-sectional view showing a schematic configuration of a liquid crystal display device 400 according to the fourth embodiment of the present invention. The liquid crystal display device 400 according to the present embodiment is configured substantially the same as the liquid crystal display device 100 according to the first embodiment with respect to the remaining configuration except for the configuration of the deformation amount detection element 70, and therefore corresponding parts are not described. Are given the same reference numerals, and redundant explanations are omitted.

  The deformation amount detection element 70 is configured to detect the deformation amount of the optical member 30. In the present embodiment, the deformation amount detection element 70 is configured to detect the amount of deflection of the optical member 30 toward the back surface, and the second protrusion. It is provided at a position close to the position where the member 52 is erected.

  Specifically, the deformation amount detecting element 70 is supported at an initial position on the back side of the optical member 30 and separated by a predetermined distance from the optical member 30 at normal temperature supported by the support portion 40b. In addition, a displacement member 371 provided to be displaceable in the direction approaching / separating from the optical member 30, that is, the depth direction Z, and a displacement amount detection unit that detects a displacement amount in the Z2 direction from the initial position of the displacement member 371. 372 and a compression coil spring 373 that urges the displacement member 371 in the direction close to the optical member 30, that is, the Z1 direction.

  The displacement member 371 is generally formed in a rod shape, and is formed of the same material as that of the first and second projecting members 51 and 52, for example. A compression coil spring 373 is attached to the displacement member 371 between the detection side end portion, which is the end portion on the back surface side, and the bottom plate 21a in the backlight chassis 21 so as to bias the displacement member 371 in the Z1 direction. The compression coil spring 373 supports the displacement member 371 so that the displacement member 371 maintains the initial position.

  The initial position is determined such that the front end of the contact side end, which is the front end of the displacement member 371, is arranged on the front side of the front end of the second projecting member 52. For example, the front end of the contact side end is determined at a position where it is disposed at the same height as the front end of the first projecting member 51.

  The displacement amount detection unit 372 includes a switch element that can switch between a conduction state and a cutoff state in accordance with the displacement of the displacement member 371. The switch element is realized by a tact switch. Therefore, when the displacement member 371 is displaced in the Z2 direction by a predetermined displacement amount, the operation amount provided in the switch element is pressed, and the displacement amount detection unit 372 is switched between the conduction state and the cutoff state. The displacement amount detection unit 372 outputs a signal indicating the state of the switch element to the control circuit board 80.

  FIG. 13 is a flowchart of drive control in the liquid crystal display device 400 according to the fourth embodiment of the present invention. This control flow is based on the premise that the liquid crystal display device 400 is always used in an operating state. Unless the temperature abnormality occurs in the liquid crystal display device 400 and the control is stopped, the liquid crystal display device 400 is not stopped.

  In step b1, the occurrence of a power ON occurrence or a return request (signal input) from a standby state (power saving mode or screen saver) is monitored. In step b2, the light source 22 is normally lit at a preset duty ratio. In step b3, a standby for a predetermined time, for example, 10 seconds is executed.

  In step b4, it is determined whether or not the tact switch is in a conductive state. If the tact switch is in a conductive state, the process proceeds to step b5, and if not, the process proceeds to step b6. In step b5, the cooling fan 60 is driven and the process proceeds to step b7. In step b6, the driving of the cooling fan 60 is stopped. In step b7, a standby is executed for a predetermined time, for example, 3 minutes. Then, the process proceeds to step b4.

  As described above, according to this embodiment, the cooling fan 60 is controlled by detecting the amount of displacement of the diffusion plate 31, that is, the amount of deflection toward the back side, so that when the temperature of the liquid crystal display device 400 increases. Degradation of the image quality can be efficiently prevented, and noise associated with driving of the cooling fan 60 can be reduced as much as possible.

  FIG. 14 is a cross-sectional view showing a schematic configuration of a liquid crystal display device 500 according to the fifth embodiment of the present invention. Since the liquid crystal display device 500 according to the present embodiment is configured substantially the same as the liquid crystal display device 100 according to the first embodiment with respect to the remaining configuration except for the configuration of the deformation amount detection element 70, the corresponding parts are not described. Are given the same reference numerals, and redundant explanations are omitted.

  The deformation amount detection element 70 is configured to detect the deformation amount of the optical member 30. In the present embodiment, the deformation amount detection element 70 is configured to detect an extension amount in the surface direction of the optical member 30. It is provided outward in the surface direction. In detail, it arrange | positions so that the amount of elongation to the long side direction of the optical member 30 may be detected.

  Specifically, the deformation amount detection element 70 includes a displacement amount detection unit 471 that detects an extension amount of the optical member 30 in the surface direction. The displacement detection unit 471 includes a switch element that can switch between a conduction state and a cutoff state as the optical member 30 extends in the surface direction. The switch element is realized by a tact switch. Therefore, when the optical member 30 is extended by a predetermined extension amount in the long side direction, the displacement amount detection unit 471 is pressed on the operation unit provided in the switch element to switch between the conduction state and the cutoff state. The displacement amount detection unit 471 outputs a signal indicating the state of the switch element to the control circuit board 80. In the present embodiment, drive control is performed according to the control flow shown in FIG.

  As described above, according to the present embodiment, the cooling fan 60 is controlled by detecting the amount of displacement of the diffusion plate 31, that is, the amount of elongation in the surface direction, so that the temperature of the liquid crystal display device 500 increases. Degradation of the image quality can be efficiently prevented, and noise associated with driving of the cooling fan 60 can be reduced as much as possible.

DESCRIPTION OF SYMBOLS 10 Liquid crystal panel 20 Backlight unit 22 Light source 30 Optical member 31 Diffusion plate 40 Frame 50 Projection part 60 Cooling fan 70 Deformation amount detection element 80 Control circuit board

Claims (7)

A liquid crystal panel capable of displaying images;
An illuminating device that is disposed on the back side of the liquid crystal panel and includes an illumination light source that illuminates the liquid crystal panel;
A plate-like member disposed between the liquid crystal panel and the illumination light source, and made of a diffusion plate or a reinforcing plate;
A support portion for supporting the peripheral portion of the plate-like member so that the plate-like member is in a parallel or substantially parallel posture with respect to the liquid crystal panel;
A cooling device for cooling the lighting device;
Deformation amount detection means for detecting the amount of extension in the surface direction of the plate-shaped member or the amount of deflection of the plate-shaped member toward the back surface;
Control means for controlling the driving of the illumination light source and / or the cooling device so as to reduce the amount of extension or deflection based on the detection result output from the deformation amount detection means. An image display device. The deformation amount detecting means includes
A displacement member provided on the back side of the plate-like member, supported at a predetermined initial position, and displaceable in a direction approaching / separating from the plate-like member;
A displacement amount detector that detects a displacement amount from an initial position of the displacement member,
The control unit controls driving of the illumination device and / or the cooling device so that the displacement member returns to an initial position based on a detection result output from the displacement amount detection unit. The image display device according to claim 1.   The image display device according to claim 2, wherein the displacement amount detection unit includes a light detection unit that optically detects a displacement amount from an initial position of the displacement member. The deformation amount detecting means further includes a deformation member that deforms according to a displacement amount from an initial position of the displacement member,
The image display device according to claim 2, wherein the displacement amount detection unit includes a strain detection unit that detects a strain amount of the deformable member. The deformation amount detecting means includes
On the back side of the plate-like member, provided fixed at a position spaced from the plate-like member, including a distance measuring unit that detects the distance to the plate-like member in a non-contact manner,
The control unit controls driving of the lighting device and / or the cooling device so that a distance to the plate-like member is larger than a predetermined distance based on a detection result output from the distance measuring unit. The image display device according to claim 1. The deformation amount detecting means includes
A displacement member provided on the back side of the plate-like member so as to be displaceable in a direction approaching / separating from the plate-like member;
A switch element capable of switching between a conduction state and a cutoff state in accordance with the displacement of the displacement member;
The said control part controls the drive of the said illuminating device and / or the said cooling device so that the said displacement member may return to an initial position based on the state of the said switch element. Image display device. The deformation amount detecting means includes
A switch element that is provided on the outer side in the surface direction of the plate-like member, and that can switch between a conductive state and a cut-off state as the plate-like member extends in the surface direction;
The said control part controls the drive of the said illuminating device and / or the said cooling device so that the expansion to the surface direction of the said plate-shaped member may reduce based on the state of the said switch element. Item 4. The image display device according to Item 1.

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