WO2022190637A1 - Liquid crystal display device - Google Patents

Liquid crystal display device Download PDF

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Publication number
WO2022190637A1
WO2022190637A1 PCT/JP2022/001386 JP2022001386W WO2022190637A1 WO 2022190637 A1 WO2022190637 A1 WO 2022190637A1 JP 2022001386 W JP2022001386 W JP 2022001386W WO 2022190637 A1 WO2022190637 A1 WO 2022190637A1
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WO
WIPO (PCT)
Prior art keywords
liquid crystal
temperature
electrode
display panel
common electrode
Prior art date
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PCT/JP2022/001386
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French (fr)
Japanese (ja)
Inventor
利範 上原
Original Assignee
株式会社ジャパンディスプレイ
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Publication date
Application filed by 株式会社ジャパンディスプレイ filed Critical 株式会社ジャパンディスプレイ
Publication of WO2022190637A1 publication Critical patent/WO2022190637A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K35/00—Instruments specially adapted for vehicles; Arrangement of instruments in or on vehicles
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals

Definitions

  • the present disclosure relates to liquid crystal display devices.
  • a head-up display By projecting an image onto a translucent member such as glass, a head-up display (HUD) makes it possible to recognize the image as if it were on the line of sight of a person looking at the member.
  • HUD head-up display
  • Sunlight may enter the HUD up to the image projection part.
  • a HUD that is provided in a vehicle such as a four-wheeled vehicle and projects an image onto the windshield
  • the sunlight entering the vehicle through the windshield may reach the liquid crystal display panel of the image projection unit. be.
  • the sunlight can heat the liquid crystal display panel to a temperature significantly higher than that during normal operation. If such a high temperature state continues for a long period of time, the liquid crystal display panel may malfunction.
  • the present disclosure has been made in view of the above problems, and an object thereof is to provide a liquid crystal display device capable of detecting when the temperature of the liquid crystal display panel becomes significantly higher than the temperature during normal operation.
  • a liquid crystal display device includes a display panel having a display region for displaying an image by controlling the alignment of liquid crystal sandwiched between two substrates facing each other in a predetermined direction; one electrode, a plurality of second electrodes provided at different positions in the display area and facing the first electrode in the predetermined direction, and between the first electrode and each of the plurality of second electrodes a determination unit that determines whether the temperature of each region where each of the plurality of second electrodes is located is equal to or higher than a predetermined temperature, based on the capacitance of the first electrode, wherein the sheet resistance of the first electrode is 10 4 ⁇ / ⁇ or less.
  • FIG. 1 is a schematic diagram showing a configuration example of a HUD unit including a liquid crystal display device according to the present disclosure.
  • FIG. 2 is a graph showing an example of the relationship between liquid crystal temperature and dielectric constant.
  • FIG. 3 is a schematic diagram showing a comparison between a display output when isotropic liquid crystal is not generated and a display output when isotropic liquid crystal is generated.
  • FIG. 4 is a schematic diagram showing the principle of detecting the temperature state of the display panel.
  • FIG. 5 is a schematic perspective view showing the relationship between the shield electrode provided on the opposing substrate and the common electrode provided on the array substrate.
  • FIG. 6 is a schematic diagram showing the positional relationship between the pixel electrode and the common electrode and the structure connected to the common electrode from a plan view.
  • FIG. 1 is a schematic diagram showing a configuration example of a HUD unit including a liquid crystal display device according to the present disclosure.
  • FIG. 2 is a graph showing an example of the relationship between liquid crystal temperature and dielectric constant.
  • FIG. 7 is a block diagram showing a main configuration example of a liquid crystal display device.
  • FIG. 8 is a graph showing dielectric constant temperature characteristics of glass and liquid crystal.
  • FIG. 9 is a graph showing the relationship between the temperature of a display panel employing glass and liquid crystal exhibiting the dielectric constant-temperature characteristics shown in FIG. 8 and the capacitance between the common electrode and the shield electrode in the display panel.
  • FIG. 10 is a graph showing the relationship between temperature and numerical value indicated by post-ADC data, corresponding to the relationship between temperature and capacitance shown in FIG.
  • FIG. 11 is a timing chart showing an operation example of the liquid crystal display device 10.
  • FIG. FIG. 12 is a timing chart showing an operation example of the liquid crystal display device 10 different from the example shown in FIG. FIG.
  • FIG. 13 is a schematic diagram showing a mechanism for detecting the temperature state of the panel with a positional relationship between the common electrode and the shield electrode different from that in FIG. 14 is a schematic diagram showing a configuration connected to the common electrode shown in FIG. 13.
  • FIG. 15 is a cross-sectional view of the signal transmission path in FIG. 14.
  • FIG. 16 is a schematic diagram showing a mechanism for detecting the temperature state of the panel with a positional relationship between the common electrode and the shield electrode different from that in FIGS. 4 and 13.
  • FIG. FIG. 17 is a graph showing the effect of glass thickness on the degree of change in capacitance caused by a 1 degree (° C.) temperature change.
  • FIG. 1 is a schematic diagram showing a configuration example of a HUD unit 100 including a liquid crystal display device 10 according to the present disclosure.
  • HUD unit 100 includes liquid crystal display device 10 , light source 50 , and concave mirror 60 .
  • the liquid crystal display device 10 includes a display panel P (see FIG. 4), which is a so-called liquid crystal display panel, and a control section 30 (see FIG. 7) that controls the operation of the liquid crystal display panel.
  • the light source 50 has a light emitting element such as an LED (Light Emitting Diode), and emits light from the rear side of the display panel P included in the liquid crystal display device 10 .
  • LED Light Emitting Diode
  • the concave mirror 60 reflects the light emitted by the light source 50 and transmitted through the liquid crystal display device 10, and guides the light to the projection target on which the image output by the HUD unit 100 is projected.
  • the term "light output from the HUD unit 100" refers to the light.
  • the windshield 70 is illustrated as the projection target.
  • the windshield 70 is, for example, the windshield of a four-wheeled vehicle or the windshield of an aircraft, but is not limited thereto.
  • the projection target may be any configuration that allows the HUD to project an image, and can be changed as appropriate.
  • the light output from the HUD unit 100 is projected onto the windshield 70.
  • light output from the HUD unit 100 projected onto the windshield 70 is schematically indicated by dashed arrows.
  • the user U who turns his line of sight to the light projected on the windshield 70, visually recognizes the virtual image VI.
  • a general vehicle having a configuration including the HUD unit 100 and the windshield 70 may be placed in an environment where sunlight from the sun SUN is irradiated.
  • the sunlight entering the vehicle through the windshield 70 may be reflected and condensed by the concave mirror 60 and illuminate the display panel P of the liquid crystal display device 10 .
  • the display panel P irradiated with sunlight may be affected by the heat of the sunlight.
  • the sunlight is schematically indicated by a solid-line arrow.
  • FIG. 2 is a graph showing an example of the relationship between the temperature and dielectric constant of the liquid crystal 15 (see FIG. 3, etc.).
  • is the dielectric constant of the liquid crystal 15 when the temperature of the liquid crystal 15 is less than Tc
  • It is a graph which shows a dielectric constant.
  • ⁇ is the dielectric constant of the liquid crystal 15 when the temperature of the liquid crystal 15 is less than Tc
  • 4 is a graph showing the dielectric constant of the liquid crystal 15 when the temperature of the liquid crystal 15 is equal to or higher than Tc .
  • the liquid crystal 15 whose temperature is lower than Tc exhibits anisotropy in which the dielectric constant is different between the alignment direction and the direction orthogonal to the alignment direction.
  • the liquid crystal 15 does not exhibit the anisotropy when the temperature of the liquid crystal 15 is equal to or higher than Tc . That is, the liquid crystal 15 whose temperature is equal to or higher than Tc exhibits isotropy in which the dielectric constant does not differ between the alignment direction and the direction orthogonal to the alignment direction.
  • the display panel P uses a temperature range below Tc as a normal operating temperature range. Therefore, when the temperature of the liquid crystal 15 is equal to or higher than Tc , an abnormality occurs due to, for example, the heat of sunlight as described above.
  • the liquid crystal 15 used in the present disclosure is a nematic liquid crystal in which liquid crystal molecules are rod-shaped.
  • indicates the permittivity in the long axis direction of the rod-like molecule
  • ⁇ ⁇ indicates the permittivity in the direction perpendicular to the long axis direction of the rod-like molecule. That is, the dielectric constant shown in FIG. 2 is the dielectric constant of a so-called positive nematic liquid crystal.
  • the dielectric constant in the long axis direction of the rod-shaped molecules and the dielectric constant in the direction perpendicular to the long axis direction of the rod-shaped molecules have a relationship that is almost reversed to that of the positive type nematic liquid crystal. .
  • FIG. 3 is a schematic diagram showing a comparison between the display output when the isotropic liquid crystal 15 is not generated and the display output when the isotropic liquid crystal 15 is generated.
  • the "state" in FIG. 3 schematically shows an example in which the orientation of the liquid crystal 15 is controlled by a so-called vertical electric field method.
  • a configuration example in which the liquid crystal 15 is sandwiched between the pixel electrode 21 and the common electrode 22 is shown by "State" in FIG.
  • the arrangement example of the pixel electrode 21 and the common electrode 22 for controlling the alignment of the liquid crystal 15 is not limited to the so-called vertical electric field method, and can be changed as appropriate. .
  • the alignment of the multiple liquid crystal molecules contained in the liquid crystal 15 has regularity and is controlled to be almost the same. This indicates that the response (orientation control) of the liquid crystal 15 according to the potential difference between the pixel electrode 21 and the common electrode 22 is established without any problem. Therefore, as illustrated in the “example of display mode” where the isotropy is “no”, the display mode of the image in the display area AA (see FIG. 4 etc.) of the display panel P of the liquid crystal display device 10 is correspond to the input image.
  • the alignment of the plurality of liquid crystal molecules contained in the liquid crystal 15 is not regular. This indicates that an abnormality occurs in the response of the liquid crystal 15 according to the potential difference between the pixel electrode 21 and the common electrode 22, and the intended orientation control is no longer established. Therefore, as illustrated in the “example of display mode” where the isotropy is “yes”, the display mode of the image in the display area AA (see FIG. 4 etc.) of the display panel P of the liquid crystal display device 10 is Unlike the image corresponding to the input image, the image is not formed at the location where the orientation control is not established, or it is very difficult to visually recognize the image even if it is formed. Locations where alignment control is not established in this way occur at hot spots HS within the display area AA.
  • the hot spot HS is caused, for example, by the heat of the sunlight described above.
  • the liquid crystal display device 10 has a mechanism for detecting the temperature state of the display panel P.
  • the detection of the temperature state here refers to detection of occurrence of temperature that affects the operation of the display panel P, such as detection of a hot spot HS.
  • FIG. 4 is a schematic diagram showing the principle of detecting the temperature state of the display panel P.
  • the display panel P has an array substrate 11 and a counter substrate 12 .
  • Liquid crystal 15 is sandwiched between array substrate 11 and counter substrate 12 .
  • two directions along the surfaces of the array substrate 11 and the counter substrate 12 are referred to as a first direction Dx and a second direction Dy.
  • the first direction Dx and the second direction Dy are orthogonal.
  • a direction perpendicular to the first direction Dx and the second direction Dy is defined as a third direction Dz.
  • the direction in which the array substrate 11 and the counter substrate 12 face each other with the liquid crystal 15 interposed therebetween is the third direction Dz.
  • both ends in the first direction Dx and both ends in the second direction Dy of the array substrate 11 and the counter substrate 12 facing each other with the liquid crystal 15 interposed therebetween are sealed with a sealing material 28 (see FIG. 15).
  • the array substrate 11 and the counter substrate 12 are substrates made of translucent materials.
  • the array substrate 11 and the counter substrate 12 in the embodiment are glass substrates.
  • glass when simply referred to as glass, it refers to the glass forming the array substrate 11 and the counter substrate 12 .
  • a pixel electrode 21 and a common electrode 22 are provided on the array substrate 11 .
  • the pixel electrode 21 is provided on the liquid crystal 15 side of the array substrate 11 and contacts the alignment film 51 . Further, the liquid crystal 15 is sealed between the alignment film 51 on the array substrate 11 side and the alignment film 52 on the counter substrate 12 side.
  • the alignment films 51 and 52 define the initial alignment of liquid crystal molecules contained in the liquid crystal 15 .
  • the initial orientation is the orientation of liquid crystal molecules when there is no effect of the electric field between the pixel electrode 21 and the common electrode 22 .
  • the common electrode 22 is provided closer to the array substrate 11 than the pixel electrode 21 is.
  • the common electrode 22 is physically and electrically separated from the pixel electrode 21 with an interlayer insulating film 27 interposed therebetween.
  • the layered structure on the array substrate side includes pixel electrodes 21, wires connected to the common electrode 22, switching elements for controlling the potential of the pixel electrodes 21, and the like.
  • the display panel P shown in FIG. 4 is a so-called lateral electric field type liquid crystal display panel. In the horizontal electric field method, the direction of the electric field generated by the potential difference between the potential of the pixel electrode 21 and the potential of the common electrode 22 has a portion parallel to the substrate surface (Dx-Dy plane).
  • FIG. 5 is a schematic perspective view showing the relationship between the shield electrode 23 provided on the counter substrate 12 and the common electrode 22 provided on the array substrate 11.
  • the opposing substrate 12 is provided with a shield electrode 23 .
  • the shield electrode 23 in the display panel P shown in FIG. 4 is provided on the surface of the counter substrate 12 opposite to the surface where the counter substrate 12 and the liquid crystal 15 face each other.
  • the shield electrode 23 is provided to have a ground potential (GND).
  • the shield electrode 23 may be connected to a ground line extending from the outside or other configuration that is stable at ground potential (GND), or may be substantially floating due to its area and film thickness. It may be configured to be ground potential (GND) even in the state.
  • the pixel electrode 21, the common electrode 22, and the shield electrode 23 are electrodes having translucency.
  • the common electrode 22 and the shield electrode 23 are light-transmitting thin-film electrodes formed using, for example, ITO (Indium Tin Oxide).
  • the shield electrode 23 covers the display area AA in plan view.
  • a planar viewpoint is a viewpoint for viewing a plane (Dx-Dy plane) perpendicular to the third direction Dz. More specifically, the shield electrode 23 is a thin-film electrode that is uniformly continuous so as to cover the entire display area AA.
  • the common electrodes 22 provided on the array substrate 11 are arranged in tiles within the display area AA.
  • a plurality of common electrodes 22 each cover a portion of the display area AA.
  • the positions of the common electrodes 22 within the display area AA are different.
  • the common electrode 22 and the shield electrode 23 each have a potential, a capacitance is generated between them.
  • the capacitance between common electrode 22 and shield electrode 23 corresponds to the dielectric constant of the structure between common electrode 22 and shield electrode 23 .
  • the relative permittivity of the counter substrate 12 located between the common electrode 22 and the shield electrode 23 and the relative permittivity of the liquid crystal layer 15 occupy the majority.
  • the capacitance generated according to the dielectric constant of the counter substrate 12 among the capacitances between the common electrode 22 and the shield electrode 23 is illustrated as C Glass .
  • the capacitance generated according to the dielectric constant of the liquid crystal 15 among the capacitances between the common electrode 22 and the shield electrode 23 is shown as CLC .
  • Each of the plurality of common electrodes 22 individually stores capacitance between itself and the shield electrode 23 . Also, the positions of the plurality of common electrodes 22 within the display area AA are different.
  • each of the plurality of common electrodes 22 is provided as a rectangular thin film electrode.
  • a partial area within the display area AA whose temperature is relatively higher than other areas is schematically illustrated as a hot spot HS.
  • the common electrode 22 is used not only for detecting the temperature state by detecting the capacitance, but also for orientation control of the liquid crystal 15 by the potential difference between the common electrode 22 and the pixel electrode 21 .
  • the common electrode 22 is controlled to have a predetermined potential.
  • a mechanism is provided to switch the electrical connection state of the common electrode 22 between when an image is displayed and when the temperature state is detected.
  • FIG. 6 is a schematic diagram showing the positional relationship between the pixel electrode 21 and the common electrode 22 and the configuration connected to the common electrode 22 from a plan view. As shown in FIGS. 5 and 6, the plurality of common electrodes 22 are arranged in a matrix when viewed from above. Each common electrode 22 is connected to the switch SW via an individual wiring.
  • common electrodes 22 are arranged in a matrix from a plan view, and these common electrodes 22 are interconnects L00, L01, L02, L03, L04, L05, L06, L07, L08, L09,
  • L00, L01, L02, L03, L04, L05, L06, L07, L08, L09 A configuration example in which the switches SW are individually connected via L10 and L11 is shown, but this is only a schematic and limits the number and arrangement of the common electrodes 22 in the actual display panel P. not. The number, arrangement, shape and other specific forms of the common electrodes 22 can be changed as appropriate.
  • the switch SW switches between a configuration in which it is connected to the common electrode 22 during image display and a configuration in which it is connected to the common electrode 22 during temperature state detection. Specifically, the switch SW connects the common electrode 22 and the common potential line VCOM during image display.
  • the potential of the common potential line VCOM for example, a fixed potential fixed to a certain potential or a ground potential (GND) can be adopted, and a pulse wave or an AC wave that oscillates at a predetermined cycle can also be adopted.
  • the potential is not limited to this, and any potential suitable for image display can be used and can be changed as appropriate.
  • the common electrode 22 during image display can be shared by a plurality of pixel electrodes 21 .
  • the relation between the pixel electrode 21 and the common electrode 22 in the actual display panel P is not limited.
  • the number, arrangement, shape and other specific forms of the pixel electrodes 21 for one common electrode 22 can be changed as appropriate.
  • the switch SW connects the common electrode 22 and the AFEIC (Analog Front End Integrated Circuit) 31 when the temperature state is detected.
  • the AFEIC 31 has terminals Rx00, Rx01, Rx02, Rx03, Rx04, Rx05, Rx06, Rx07, Rx08, Rx09, Rx10, Rx11 corresponding to the number of wirings L00, L01, .
  • the switches SW individually connect the wirings L00, L01, . . . , L11 and the terminals Rx00, L01, . 6, the numbers attached to the ends of the symbols of the wirings L00, L01, . It is provided so that it can be connected to
  • FIG. 7 is a block diagram showing a main configuration example of the liquid crystal display device 10.
  • the liquid crystal display device 10 includes a display panel P and a control section 30 .
  • the control unit 30 includes an AFEIC 31 , a host controller 32 and a HUD controller 33 . , L11 and terminals Rx00, L01, . . . , L11. It is a circuit that individually acquires from a plurality of common electrodes 22 electrical signals corresponding to the electrostatic capacitances generated between.
  • the host controller 32 is a circuit connected with the AFEIC 31 .
  • the host controller 32 identifies the temperature state of each partial region of the display panel P corresponding to the arrangement of each of the plurality of common electrodes 22 based on the electrical signal acquired by the AFEIC 31 .
  • the HUD controller 33 is a circuit connected with the host controller 32 .
  • the HUD controller 33 controls the operation of the display panel P based on the temperature state of each partial area of the display panel P specified by the host controller 32 .
  • the circuits included in the control unit 30 may be directly mounted on the array substrate 11, or may be electrically connected to the array substrate 11, such as a flexible printed substrate connected to the array substrate 11 so as to extend from the array substrate 11. It may be mounted in a configuration other than the array substrate 11 having.
  • the flexible printed board includes at least a plurality of wirings individually connected to the wirings L00, L01, .
  • the electrical signal acquired by the AFEIC 31 is an analog signal.
  • the processing of the host controller 32 and the HUD controller 33 are digital processing. Therefore, although not shown, the controller 30 is provided with an analog/digital converter (ADC) that converts the electrical signal into a digital signal.
  • ADC analog/digital converter
  • the ADC unit is provided within the AFEIC 31 , within the host controller 32 , or as an independent configuration between the AFEIC 31 and the host controller 32 .
  • post-ADC data it refers to data obtained by converting an electrical signal into digital data by the ADC section.
  • FIG. 8 is a graph showing dielectric constant temperature characteristics of glass and liquid crystal 15.
  • the relative permittivity of glass increases in proportion to the increase in temperature.
  • the liquid crystal 15 includes a phase transition temperature zone PT1 between 80 degrees (° C.) and 100 degrees (° C.), in which the increase in the relative permittivity with respect to the temperature rise is sharper than in the other temperature zones.
  • the aforementioned T c is the temperature of the phase transition temperature zone PT1.
  • the liquid crystal 15 has a relative permittivity that increases in proportion to temperature rise in a temperature range other than the phase transition temperature range PT1.
  • FIG. 9 shows the relationship between the temperature of the display panel P employing the glass and liquid crystal 15 exhibiting the dielectric constant-temperature characteristics shown in FIG. 8 and the capacitance between the common electrode 22 and the shield electrode 23 in the display panel P. is a graph showing
  • the capacitance between the common electrode 22 and the shield electrode 23 is affected by the dielectric constant of the glass and the dielectric constant of the liquid crystal 15 .
  • the relative dielectric constant of glass exhibits a change proportional to the change in temperature, and the variation pattern of the relative dielectric constant of the liquid crystal 15 includes the phase transition temperature zone PT1.
  • band PT2 in the configuration of the display panel P shown in FIG. 4, as shown in "glass + liquid crystal" in FIG.
  • the temperature zone PT2 corresponds to the temperature zone of the phase transition temperature zone PT1. It should be noted that the capacitance between the common electrode 22 and the shield electrode 23 increases in proportion to the rise in temperature in a temperature zone other than the temperature zone PT2.
  • FIG. 10 is a graph showing the relationship between temperature and numerical value indicated by post-ADC data, corresponding to the relationship between temperature and capacitance shown in FIG.
  • the AFEIC 31 acquires electrical signals corresponding to the capacitance between the common electrode 22 and the shield electrode 23.
  • FIG. The electrical signal is converted into post-ADC data by the ADC section.
  • the post-ADC data is numerical data indicating the strength of the electrical signal corresponding to the magnitude of the electrostatic energy between the common electrode 22 and the shield electrode 23 . Therefore, the relationship between the numerical value indicated by the ADC data and the temperature is the same as the relationship between the capacitance and the temperature described with reference to FIG. Specifically, as shown in FIG.
  • the temperature zone PT3 corresponds to the temperature zones of the phase transition temperature zone PT1 and the temperature zone PT2. Note that the numerical value indicated by the ADC data increases in proportion to the increase in temperature in temperature zones other than the temperature zone PT3.
  • the post-ADC data value TL1 is less than the value BL, it may be treated as a sign that a hot spot HS will occur in PL.
  • the host controller 32 outputs an output indicating that fact.
  • the HUD controller 33 stops the operation of the display panel P according to the output. As a result, it is possible to prevent the display output from being performed in a state where the orientation control of the liquid crystal 15 is not established, such as the hot spot HS described with reference to FIG.
  • the display panel P has a hot spot HS.
  • the host controller 32 outputs an output indicating that fact.
  • the HUD controller 33 stops the operation of the display panel P according to the output. As a result, it is possible to prevent display output from being continued in a state where alignment control of the liquid crystal 15 is not established, such as the hot spot HS described with reference to FIG.
  • the fact that the value TL2 was obtained indicates that the temperature zone PT3 has undergone a state in which "the increase in the numerical value indicated by the ADC data with respect to the rise in temperature increases rapidly compared to other temperature zones". Therefore, with such a significant increase in the post-ADC data value, the operation of the display panel P can be determined with confirmation that the hotspot HS is more likely to occur.
  • the host controller 32 performs output based on the value of post-ADC data, but the host controller 32 specifies the temperature of the display panel P corresponding to the value of the post-ADC data, and The configuration may be such that when the temperature obtained is equal to or higher than a predetermined temperature, an output indicating that fact is made.
  • the host controller 32 is a circuit that holds data indicating the correspondence between the value of post-ADC data and the temperature of the display panel P, or a circuit that has a function of referring to the data from an external configuration that stores the data. be.
  • the capacitance between the common electrode 22 and the shield electrode 23 may be affected.
  • This effect is due to the fact that the electric field generated by the electrostatic energy stored between the common electrode 22 and the shield electrode 23 extends to the outside of the shield electrode 23 side, and that an external structure is unintentionally brought into proximity or contact with the electric field. occurs when Due to this influence, there is a possibility that the detection accuracy of the temperature state based on the electrostatic capacitance between the common electrode 22 and the shield electrode 23 is lowered. Therefore, the liquid crystal display device 10 employs the shield electrode 23 having a sheet resistance that can sufficiently suppress the influence. Specifically, the sheet resistance of the shield electrode 23 is 10 4 ⁇ / ⁇ or less.
  • the shield electrode 23 is a thin film covering the display area AA. That is, when viewed from the common electrode 22 side in a plan view, the shield electrode 23 has no opening. This can sufficiently suppress the influence of the electric field generated by the electrostatic energy stored between the common electrode 22 and the shield electrode 23 extending to the outside of the shield electrode 23 side.
  • the thickness of Dz is 3.0 ⁇ m.
  • the thickness of the counter substrate 12 in the third direction Dz was 200.0 ⁇ m.
  • the resolution of the ADC section that is, the minimum unit of input (capacitance) that can be recognized by the ADC section is, for example, 10 pf.
  • the post-ADC data is, for example, 12 bits.
  • the display panel P periodically updates the display output of the frame image according to the input image signal.
  • the update frame rate is, for example, 60 Hz, 120 Hz, or 240 Hz, but is not limited to these and can be changed as appropriate.
  • one frame period includes a liquid crystal drive period and a temperature detection period.
  • the liquid crystal drive period is a period during which the pixels of the display panel P in which the pixel electrodes 21 are individually provided are driven for image display. More specifically, the liquid crystal drive period is a period in which the potential of each of the plurality of pixel electrodes 21 is individually controlled, and liquid crystal molecules are driven in each pixel according to the potential.
  • the temperature detection period is a period during which the temperature state of the display panel P is detected by the liquid crystal display device 10 .
  • the switch SW connects the common electrode 22 and the AFEIC 31 .
  • FIG. 11 is a timing chart showing an operation example of the liquid crystal display device 10.
  • FIG. 11 Each of the frame periods F1, F2, and F3 is one frame period. As shown in FIG. 11, one liquid crystal drive period and one temperature detection period may occur during one frame period. Although not shown in FIG. 11, after the frame period F3, a frame period in which one liquid crystal drive period and one temperature detection period occur continues at a cycle corresponding to the frame rate.
  • FIG. 12 is a timing chart showing an operation example of the liquid crystal display device 10 different from the example shown in FIG.
  • the liquid crystal drive period and the temperature detection period may occur multiple times during one frame period. Specifically, for example, as shown in FIG. 12, the liquid crystal drive period and the temperature detection period may occur three times during one frame period.
  • a so-called field sequential color (FSC) system that controls pixels so that light of a plurality of colors is transmitted from one pixel at different timings.
  • Field Sequential Color Field Sequential Color
  • a red (R) image is output in one of the three times, and a green (G) image is output in the other one.
  • a color image is output by outputting a blue (B) image at another time.
  • the temperature detection period is set after each liquid crystal drive period that occurs multiple times during one frame period. Although not shown in FIG. 12, even after the frame period F1, a frame period in which the liquid crystal drive period and the temperature detection period alternately occur multiple times continues at a cycle corresponding to the frame rate.
  • the number of liquid crystal drive periods and the number of temperature detection periods are the same, but the present invention is not limited to this. That is, the number of liquid crystal drive periods and the number of temperature detection periods that occur during one frame period may be different. For example, a plurality of liquid crystal drive periods and one temperature detection period may occur during one frame period. Specifically, in the example described with reference to FIG. 11, the temperature state of each partial region is simultaneously detected by all the common electrodes 22 in each temperature detection period, whereas in the example described with reference to FIG. Alternatively, the temperature state may be detected by one of the plurality of common electrodes 22 for each temperature detection period.
  • the sequential relationship between the liquid crystal drive period and the temperature detection period in one frame period can be changed as appropriate. That is, the liquid crystal drive period may occur after the temperature detection period.
  • the liquid crystal drive period may occur after the temperature detection period.
  • FIGS. 11 and 12 there is a period that is neither a liquid crystal drive period nor a temperature detection period within the frame period, but this is a blanking period during which processing such as resetting the potential of the pixel electrode 21 is performed.
  • the switching control between the liquid crystal drive period and the temperature detection period shown in FIGS. 11 and 12 is performed by the HUD controller 33, for example, but may be performed by another configuration.
  • a timing controller that performs operation timing control of a source driver that is provided in the display panel P and outputs a signal to be applied to the pixel electrode 21 of each pixel and a gate driver that sequentially scans and drives the switching element of each pixel performs the switching control. you can go
  • the display panel P shown in FIG. 4 has been described above as an example. It is not limited.
  • FIG. 13 is a schematic diagram showing a mechanism for detecting the temperature state of the panel with a positional relationship between the common electrode 22 and the shield electrode 23 different from that in FIG.
  • the display panel P described above may be replaced with a display panel P2.
  • the display panel P2 has a common electrode 22 provided on the counter substrate 12, as shown in FIG.
  • the display panel P shown in FIG. 13 is a so-called vertical electric field type liquid crystal display panel.
  • the direction of the electric field generated by the potential difference between the potential of the pixel electrode 21 and the potential of the common electrode 22 corresponds to the opposing direction (third direction Dz) between the array substrate 11 and the counter substrate 12 .
  • a configuration in which a polarizing plate (not shown) is provided over the shield electrode 23 can also be adopted.
  • FIG. 14 is a schematic diagram showing a configuration connected to the common electrode 22 shown in FIG. 15 is a cross-sectional view of the signal transmission path Ex in FIG. 14.
  • FIG. 14 In the display panel P2, wirings L00, L01, .
  • the wiring connected to the common electrode 22 cannot be completed within the interlayer film 27, and it is necessary to form a signal transmission path between the array substrate 11 and the counter substrate 12.
  • FIG. Therefore, the signal transmission path Ex is provided in the display panel P2.
  • signal transmission paths Ex are provided between the wirings L00, L01, . . . , L11 and the terminals Rx00, Rx01, .
  • the signal transmission path Ex includes conductive particles 25 and wiring 26 .
  • the conductive particles 25 are positioned between the array substrate 11 and the counter substrate 12 and establish an electrical connection between the wiring L11 and the wiring 26.
  • FIG. 15 is a Dy-Dz cross-sectional view at the position of the wiring L11 shown in FIG. 14, so that the conductive particles 25 and the wiring L11 are connected.
  • the conductive particle 25 connects the wiring 26 with any one of the wirings L00, L01, . . . , L10.
  • the wiring 26 is provided on the side of the array substrate 11 and connected to any one of the terminals Rx00, Rx01, . . . , Rx11. Although the pixel electrode 21 is not shown in FIG. 15, the wiring 26 is insulated from the pixel electrode 21 by the interlayer film 27 . In the display panel P2, the numerical values added to the end of the symbols of the wirings L00, L01, . It is the same as the display panel P in that they are individually connected.
  • the counter substrate 12 is between the common electrode 22 and the shield electrode 23, and the liquid crystal 15 is not provided. Therefore, in the display panel P2, glass, which is the material of the counter substrate 12, exists between the common electrode 22 and the shield electrode 23. As shown in FIG. In this case, the capacitance between the common electrode 22 and the shield electrode 23 is affected by the dielectric constant of the glass and is not affected by the dielectric constant of the liquid crystal 15 . As described with reference to FIG. 8, the dielectric constant of glass shows a change proportional to the change in temperature. Therefore, in the configuration of the display panel P2, the capacitance increases in proportion to the temperature rise, as indicated by "glass" in FIG.
  • the operation control of the display panel P2 can be performed in the same manner as the operation control of the display panel P based on the value TL1 or the value TL2.
  • FIG. 16 is a schematic diagram showing a mechanism for detecting the temperature state of the panel with a positional relationship between the common electrode 22 and the shield electrode 23 different from that shown in FIGS.
  • the display panel P described above may be replaced with a display panel P3.
  • a display panel P3 shown in FIG. 16 differs from the display panel P shown in FIG. Accordingly, in the display panel P3, the liquid crystal 15 is present between the common electrode 22 and the shield electrode 23, and the opposing substrate 12 is absent. In this case, the capacitance between the common electrode 22 and the shield electrode 23 is affected by the dielectric constant of the liquid crystal 15 and is not affected by the dielectric constant of the glass.
  • the display panel P3 is the same as the display panel P in other respects.
  • a polarizing plate 61 is provided on the display surface side of the counter substrate 12 .
  • the polarizing plate 61 is adhered to the opposing substrate 12 .
  • the liquid crystal display device 10 includes liquid crystal sandwiched between two substrates (array substrate 11 and counter substrate 12) facing each other in a predetermined direction (third direction Dz).
  • a display panel for example, a display panel P
  • a display panel P having a display area AA for displaying an image by controlling the orientation of 15, a first electrode (shield electrode 23) covering the display area, and different positions in the display area.
  • the predetermined temperature refers to the temperature of the display panel P at which the value of the post-ADC data becomes a threshold value (for example, the value TL1, the value BL, or the value TL2).
  • the sheet resistance of the first electrode is 10 4 ⁇ / ⁇ or less.
  • HUD controller 33 that stops the operation of the display panel (for example, display panel P) when the temperature detected by the determination unit (host controller 32) is equal to or higher than a predetermined temperature.
  • HUD controller 33 stops the operation of the display panel (for example, display panel P) when the temperature detected by the determination unit (host controller 32) is equal to or higher than a predetermined temperature.
  • the operation of the display panel can be stopped when the temperature of the display panel becomes significantly higher than the temperature during normal operation. Therefore, it is possible to suppress the occurrence of a state in which the display panel, which may have become unable to normally output an image corresponding to the input, continues to operate. That is, it is possible to suppress abnormal image output due to the temperature of the display panel becoming significantly higher than the temperature during normal operation.
  • the predetermined temperature is less than the phase transition temperature (T c ) between the temperature at which the liquid crystal 15 exhibits anisotropy and the temperature at which the liquid crystal 15 exhibits isotropy.
  • T c phase transition temperature
  • the temperature below the phase transition temperature (T c ) is preferably a temperature above the temperature range (for example, ⁇ 40 degrees (° C.) to 90 degrees (° C.)) in which the operation of the display panel is assumed. .
  • the predetermined temperature is equal to or higher than the phase transition temperature (T c ) between the temperature at which the liquid crystal 15 exhibits anisotropy and the temperature at which the liquid crystal 15 exhibits isotropy.
  • T c phase transition temperature
  • a significantly large change in the dielectric constant of the liquid crystal 15 that occurs at the phase transition temperature can be used to more reliably detect the temperature of the display panel (for example, the display panel P). Therefore, it is possible to further improve the accuracy of determining whether the temperature of each region where each of the plurality of second electrodes is located is equal to or higher than the predetermined temperature.
  • first electrode shield electrode 23
  • second electrode common electrode 22
  • first electrode shield electrode 23
  • second electrode common electrode 22
  • the second electrode (common electrode 22) generates an electric field that determines the orientation of the liquid crystal 15 between the second electrode (common electrode 22) and the pixel electrode 21 of the display panel (for example, the display panel P) during image display.
  • the second electrode can be used both when displaying an image and when detecting a temperature state. can realize a low-cost display panel.
  • the common electrode 22 is divided into a plurality of areas within the display area AA, the influence of the heat generated by the hotspot HS on the electrical resistance of the common electrode 22 can be transferred to the common electrode 22 corresponding to the position of the hotspot HS. can be generated intensively. Therefore, the operation control of the display panel P corresponding to the occurrence of the hot spot HS can be performed more reliably.
  • the temperature state of the display panel P In order to further improve detection accuracy, it is desirable to appropriately determine the glass thickness of the opposing substrate 12 .
  • FIG. 17 is a graph showing the effect of glass thickness on the degree of change in capacitance caused by a temperature change of 1 degree (°C).
  • the degree of change in capacitance caused by a temperature change of 1 degree (° C.) is indicated as “detected capacitance difference per 1 degree (fF/° C.)”.
  • the degree of change in capacitance caused by a temperature change of 1 degree (° C.) decreases. Therefore, in a configuration in which the counter substrate 12 is positioned between the common electrode 22 and the shield electrode 23, such as the display panel P (see FIG. 4) and the display panel P2 (see FIG.
  • the glass thickness of the counter substrate 12 is Making it thinner makes it easier to detect temperature changes more reliably. Therefore, in the display panel P and the display panel P2, it is desirable to reduce the thickness of the glass within a range in which the physical strength of the opposing substrate 12 is not impaired. Specifically, as shown by the reference line GL in FIG. 17, if the detected capacitance difference per degree is 10.0 (fF/° C.) or more, the temperature state of the host controller 32 based on post-ADC data is It is possible to obtain sufficient accuracy for detection and operation control of the HUD controller 33 . If the thickness of the counter substrate 12 is 200 ⁇ m or less, such a detection capacitance difference of 10.0 (fF/° C.) or more is sufficiently generated. Therefore, it is desirable that the thickness of the opposing substrate 12 is 200 ⁇ m or less.
  • the higher the resolution of the ADC section the more relaxed the requirements for the thickness of the opposing substrate 12 (to make it thinner). Therefore, it is desirable that the thickness of the counter substrate 12 corresponds to the resolution of the ADC section.
  • the HUD controller 33 stops the operation of the entire display panel P when post-ADC data equal to or greater than a threshold value (for example, the value TL1, the value BL, or the value TL2) is generated in the display panel P.
  • a threshold value for example, the value TL1, the value BL, or the value TL2
  • the operation control of the display panel P corresponding to the detection of the temperature state is not limited to stopping the operation of the display panel P as a whole.
  • the HUD is based on the partial region of the display panel P corresponding to the position of the common electrode 22 where the capacitance that caused post-ADC data equal to or greater than a threshold value (eg, value TL1, value BL, or value TL2) was detected.
  • the controller 33 may stop the operation of some pixels of the display panel P.
  • the HUD controller 33 stops the operation of the pixels included in the partial area or the pixels included in the partial area and a partial area around the partial area, and the display output by the operation of the other pixels. may be continued. Furthermore, the HUD controller 33 stops the irradiation of the light from the light source 50 to the area (stop area) where the operation of the pixels is stopped, so that the temperature rise of the stop area can be suppressed more reliably. Further, even after the operation of the pixels in the stop area is stopped, the temperature state detection of the partial area is continued, and when the display panel P returns to a temperature state in which the display panel P can operate without problems, the HUD controller 33 is included in the stop area. The operation of the pixel may be resumed.
  • liquid crystal display device 11 array substrate 12 counter substrate 15 liquid crystal 22 common electrode 23 shield electrode 32 host controller 33 HUD controller 100 HUD P display panel

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Abstract

This liquid crystal display device comprises: a display panel having a display region for displaying an image by controlling the alignment of liquid crystals sandwiched between two substrates opposing each other in a predetermined direction; a first electrode that covers the display region; a plurality of second electrodes that are provided at positions different from one another in the display region and that are opposed to the first electrode in a predetermined direction; and a determination unit for determining whether, on the basis of the electrostatic capacitances between the first electrode and the plurality of second electrodes, the temperature of each of the regions in which the plurality of second electrodes are located is at least a predetermined temperature. The sheet resistance of the first electrode is 104 Ω/□ or less.

Description

液晶表示装置liquid crystal display
　本開示は、液晶表示装置に関する。 The present disclosure relates to liquid crystal display devices.
　ガラス等の透光性を有する部材に画像を投影することで、当該部材に視線を向けたヒトの視線上に画像があるかのように認識させるヘッドアップディスプレイ（ＨＵＤ：Ｈｅａｄ　Ｕｐ　Ｄｉｓｐｌａｙ）が知られている（例えば特許文献１）。 By projecting an image onto a translucent member such as glass, a head-up display (HUD) makes it possible to recognize the image as if it were on the line of sight of a person looking at the member. (For example, Patent Document 1).
特開２０１４－１２３０７６号公報JP 2014-123076 A
　ＨＵＤには、画像投影部まで太陽光が進入することがある。具体例として、四輪車両等の自動車に設けられてフロントガラスに画像を投影するＨＵＤにおいて、フロントガラスを透過して車両内に進入した太陽光が画像投影部の液晶表示パネルまで到達することがある。これによって、太陽光によって液晶表示パネルが通常動作時の温度よりも著しく高温になるまで熱せられることがある。かかる高温状態が長期間続くと、液晶表示パネルが不具合をきたす虞がある。このことを踏まえ、液晶表示パネルが通常動作時の温度よりも著しく高温になったことを検出可能な仕組みが求められていた。 Sunlight may enter the HUD up to the image projection part. As a specific example, in a HUD that is provided in a vehicle such as a four-wheeled vehicle and projects an image onto the windshield, the sunlight entering the vehicle through the windshield may reach the liquid crystal display panel of the image projection unit. be. As a result, the sunlight can heat the liquid crystal display panel to a temperature significantly higher than that during normal operation. If such a high temperature state continues for a long period of time, the liquid crystal display panel may malfunction. In view of this, there has been a demand for a mechanism capable of detecting when the temperature of the liquid crystal display panel has become significantly higher than the temperature during normal operation.
　本開示は、上記の課題に鑑みてなされたもので、液晶表示パネルが通常動作時の温度よりも著しく高温になったことを検出可能な液晶表示装置を提供することを目的とする。 The present disclosure has been made in view of the above problems, and an object thereof is to provide a liquid crystal display device capable of detecting when the temperature of the liquid crystal display panel becomes significantly higher than the temperature during normal operation.
　本開示の一態様による液晶表示装置は、所定方向に対向する２つの基板の間に挟まれた液晶の配向を制御して画像を表示する表示領域を有する表示パネルと、前記表示領域を覆う第１電極と、前記表示領域内のそれぞれ異なる位置に設けられて前記第１電極と前記所定方向に対向する複数の第２電極と、前記第１電極と前記複数の第２電極の各々との間の静電容量に基づいて、前記複数の第２電極の各々が位置する領域毎の温度が所定温度以上であるか判定する判定部と、を備え、前記第１電極のシート抵抗は、１０４Ω／□以下である。 A liquid crystal display device according to an aspect of the present disclosure includes a display panel having a display region for displaying an image by controlling the alignment of liquid crystal sandwiched between two substrates facing each other in a predetermined direction; one electrode, a plurality of second electrodes provided at different positions in the display area and facing the first electrode in the predetermined direction, and between the first electrode and each of the plurality of second electrodes a determination unit that determines whether the temperature of each region where each of the plurality of second electrodes is located is equal to or higher than a predetermined temperature, based on the capacitance of the first electrode, wherein the sheet resistance of the first electrode is 10 4 Ω/□ or less.
図１は、本開示による液晶表示装置を含むＨＵＤユニットの構成例を示す模式図である。FIG. 1 is a schematic diagram showing a configuration example of a HUD unit including a liquid crystal display device according to the present disclosure. 図２は、液晶の温度と誘電率との関係の一例を示すグラフである。FIG. 2 is a graph showing an example of the relationship between liquid crystal temperature and dielectric constant. 図３は、等方性を示す液晶が生じていない場合の表示出力と、等方性を示す液晶が生じた場合の表示出力との比較を示す模式図である。FIG. 3 is a schematic diagram showing a comparison between a display output when isotropic liquid crystal is not generated and a display output when isotropic liquid crystal is generated. 図４は、表示パネルの温度状態を検出する原理を示す模式図である。FIG. 4 is a schematic diagram showing the principle of detecting the temperature state of the display panel. 図５は、対向基板に設けられたシールド電極とアレイ基板に設けられた共通電極との関係を示す模式的な斜視図である。FIG. 5 is a schematic perspective view showing the relationship between the shield electrode provided on the opposing substrate and the common electrode provided on the array substrate. 図６は、平面視点での画素電極と共通電極との位置関係及び共通電極に接続される構成を示す模式図である。FIG. 6 is a schematic diagram showing the positional relationship between the pixel electrode and the common electrode and the structure connected to the common electrode from a plan view. 図７は、液晶表示装置の主要構成例を示すブロック図である。FIG. 7 is a block diagram showing a main configuration example of a liquid crystal display device. 図８は、ガラスと液晶の誘電率温度特性を示すグラフである。FIG. 8 is a graph showing dielectric constant temperature characteristics of glass and liquid crystal. 図９は、図８に示す誘電率温度特性を示すガラスと液晶が採用された表示パネルの温度と当該表示パネルにおける共通電極とシールド電極との間の静電容量との関係を示すグラフである。FIG. 9 is a graph showing the relationship between the temperature of a display panel employing glass and liquid crystal exhibiting the dielectric constant-temperature characteristics shown in FIG. 8 and the capacitance between the common electrode and the shield electrode in the display panel. . 図１０は、図９に示す温度と静電容量との関係に対応した、温度とＡＤＣ後データが示す数値との関係を示すグラフである。FIG. 10 is a graph showing the relationship between temperature and numerical value indicated by post-ADC data, corresponding to the relationship between temperature and capacitance shown in FIG. 図１１は、液晶表示装置１０の動作例を示すタイミングチャートである。FIG. 11 is a timing chart showing an operation example of the liquid crystal display device 10. FIG. 図１２は、図１１に示す例とは異なる液晶表示装置１０の動作例を示すタイミングチャートである。FIG. 12 is a timing chart showing an operation example of the liquid crystal display device 10 different from the example shown in FIG. 図１３は、図４とは異なる共通電極とシールド電極との位置関係でパネルの温度状態を検出する仕組みを示す模式図である。FIG. 13 is a schematic diagram showing a mechanism for detecting the temperature state of the panel with a positional relationship between the common electrode and the shield electrode different from that in FIG. 図１４は、図１３に示す共通電極に接続される構成を示す模式図である。14 is a schematic diagram showing a configuration connected to the common electrode shown in FIG. 13. FIG. 図１５は、図１４における信号伝送経路の断面図である。15 is a cross-sectional view of the signal transmission path in FIG. 14. FIG. 図１６は、図４及び図１３とは異なる共通電極とシールド電極との位置関係でパネルの温度状態を検出する仕組みを示す模式図である。FIG. 16 is a schematic diagram showing a mechanism for detecting the temperature state of the panel with a positional relationship between the common electrode and the shield electrode different from that in FIGS. 4 and 13. In FIG. 図１７は、１度（℃）の温度変化により生じる静電容量の変化の度合いに対してガラス厚がもたらす影響を示すグラフである。FIG. 17 is a graph showing the effect of glass thickness on the degree of change in capacitance caused by a 1 degree (° C.) temperature change.
　以下に、本開示の各実施の形態について、図面を参照しつつ説明する。なお、開示はあくまで一例にすぎず、当業者において、発明の主旨を保っての適宜変更について容易に想到し得るものについては、当然に本開示の範囲に含有されるものである。また、図面は説明をより明確にするため、実際の態様に比べ、各部の幅、厚さ、形状等について模式的に表される場合があるが、あくまで一例であって、本開示の解釈を限定するものではない。また、本明細書と各図において、既出の図に関して前述したものと同様の要素には、同一の符号を付して、詳細な説明を適宜省略することがある。 Each embodiment of the present disclosure will be described below with reference to the drawings. It should be noted that the disclosure is merely an example, and those skilled in the art can easily conceive of appropriate modifications while maintaining the gist of the invention are, of course, included in the scope of the present disclosure. In addition, in order to make the description clearer, the drawings may schematically show the width, thickness, shape, etc. of each part compared to the actual embodiment, but this is only an example, and the interpretation of the present disclosure is not intended. It is not limited. In addition, in this specification and each figure, the same reference numerals may be given to the same elements as those described above with respect to the existing figures, and detailed description thereof may be omitted as appropriate.
　図１は、本開示による液晶表示装置１０を含むＨＵＤユニット１００の構成例を示す模式図である。ＨＵＤユニット１００は、液晶表示装置１０と、光源５０と、凹面鏡６０と、を含む。液晶表示装置１０は、いわゆる液晶表示パネルである表示パネルＰ（図４参照）と、当該液晶表示パネルの動作を制御する制御部３０（図７参照）とを含む。光源５０は、例えばＬＥＤ（Ｌｉｇｈｔ　Ｅｍｉｔｔｉｎｇ　Ｄｉｏｄｅ）等の発光素子を有し、液晶表示装置１０が有する表示パネルＰの背面側から光を照射する。 FIG. 1 is a schematic diagram showing a configuration example of a HUD unit 100 including a liquid crystal display device 10 according to the present disclosure. HUD unit 100 includes liquid crystal display device 10 , light source 50 , and concave mirror 60 . The liquid crystal display device 10 includes a display panel P (see FIG. 4), which is a so-called liquid crystal display panel, and a control section 30 (see FIG. 7) that controls the operation of the liquid crystal display panel. The light source 50 has a light emitting element such as an LED (Light Emitting Diode), and emits light from the rear side of the display panel P included in the liquid crystal display device 10 .
　凹面鏡６０は、光源５０が照射して液晶表示装置１０を透過した光を反射して、ＨＵＤユニット１００が出力した画像が投影される投影対象へ当該光を導く。以下、ＨＵＤユニット１００から出力された光と記載した場合、当該光をさす。図１では、当該投影対象として、フロントガラス７０が例示されている。フロントガラス７０は、例えば四輪車両のフロントガラスや航空機のフロントガラスであるが、これに限られるものでない。当該投影対象は、ＨＵＤが画像を投影可能な構成であればよく、適宜変更可能である。 The concave mirror 60 reflects the light emitted by the light source 50 and transmitted through the liquid crystal display device 10, and guides the light to the projection target on which the image output by the HUD unit 100 is projected. Hereinafter, when the term "light output from the HUD unit 100" is used, it refers to the light. In FIG. 1, the windshield 70 is illustrated as the projection target. The windshield 70 is, for example, the windshield of a four-wheeled vehicle or the windshield of an aircraft, but is not limited thereto. The projection target may be any configuration that allows the HUD to project an image, and can be changed as appropriate.
　ＨＵＤユニット１００から出力された光は、フロントガラス７０に投影される。図１では、フロントガラス７０に投影されるＨＵＤユニット１００から出力された光を破線の矢印で模式的に示している。フロントガラス７０に投影された当該光に視線を向けたユーザＵは、虚像ＶＩを視認する。 The light output from the HUD unit 100 is projected onto the windshield 70. In FIG. 1 , light output from the HUD unit 100 projected onto the windshield 70 is schematically indicated by dashed arrows. The user U, who turns his line of sight to the light projected on the windshield 70, visually recognizes the virtual image VI.
　ところで、ＨＵＤユニット１００及びフロントガラス７０を備える構成として一般的な乗り物は、太陽ＳＵＮからの太陽光が照射される環境下に置かれることがある。フロントガラス７０を透過して当該乗り物内に進入した太陽光は、凹面鏡６０で反射、集光されて液晶表示装置１０の表示パネルＰに照射されることがある。太陽光が照射された表示パネルＰでは、太陽光の熱による影響が現れることがある。図１では、太陽光を実線の矢印で模式的に示している。 By the way, a general vehicle having a configuration including the HUD unit 100 and the windshield 70 may be placed in an environment where sunlight from the sun SUN is irradiated. The sunlight entering the vehicle through the windshield 70 may be reflected and condensed by the concave mirror 60 and illuminate the display panel P of the liquid crystal display device 10 . The display panel P irradiated with sunlight may be affected by the heat of the sunlight. In FIG. 1, the sunlight is schematically indicated by a solid-line arrow.
　図２は、液晶１５（図３等参照）の温度と誘電率との関係の一例を示すグラフである。ε||は、液晶１５の温度がＴｃ未満である場合に液晶１５が示す誘電率であって、表示パネルＰに設けられた液晶配向子（Ｄｉｒｅｃｔｏｒ）が規定する配向方向に沿う液晶１５の誘電率を示すグラフである。ε⊥は、液晶１５の温度がＴｃ未満である場合に液晶１５が示す誘電率であって、当該配向方向に直交する方向に沿う液晶１５の誘電率を示すグラフである。液晶１５の温度がＴｃ以上である場合の液晶１５の誘電率を示すグラフである。 FIG. 2 is a graph showing an example of the relationship between the temperature and dielectric constant of the liquid crystal 15 (see FIG. 3, etc.). ε || is the dielectric constant of the liquid crystal 15 when the temperature of the liquid crystal 15 is less than Tc , and It is a graph which shows a dielectric constant. ε⊥ is the dielectric constant of the liquid crystal 15 when the temperature of the liquid crystal 15 is less than Tc , and is a graph showing the dielectric constant of the liquid crystal 15 along the direction orthogonal to the alignment direction. 4 is a graph showing the dielectric constant of the liquid crystal 15 when the temperature of the liquid crystal 15 is equal to or higher than Tc .
　図２に示すように、温度がＴｃ未満である液晶１５は、当該配向方向と、当該配向方向に直交する方向と、で誘電率が異なる異方性を示す。一方、液晶１５は、液晶１５の温度がＴｃ以上である場合、当該異方性を示さなくなる。すなわち、温度がＴｃ以上である液晶１５は、当該配向方向と、当該配向方向に直交する方向と、で誘電率が異ならない等方性を示す。表示パネルＰは、Ｔｃ未満の温度帯を通常の動作温度帯としている。従って、液晶１５の温度がＴｃ以上である時は、例えば上述の太陽光の熱による影響で生じる異常時に生じる。 As shown in FIG. 2, the liquid crystal 15 whose temperature is lower than Tc exhibits anisotropy in which the dielectric constant is different between the alignment direction and the direction orthogonal to the alignment direction. On the other hand, the liquid crystal 15 does not exhibit the anisotropy when the temperature of the liquid crystal 15 is equal to or higher than Tc . That is, the liquid crystal 15 whose temperature is equal to or higher than Tc exhibits isotropy in which the dielectric constant does not differ between the alignment direction and the direction orthogonal to the alignment direction. The display panel P uses a temperature range below Tc as a normal operating temperature range. Therefore, when the temperature of the liquid crystal 15 is equal to or higher than Tc , an abnormality occurs due to, for example, the heat of sunlight as described above.
　なお、本開示で利用される液晶１５は、液晶分子の形状が棒状のネマティック液晶である。また、図２では、ε||が棒状分子の長軸方向の誘電率を示し、ε⊥が棒状分子の長軸方向に垂直な方向の誘電率を示している。すなわち、図２に示す誘電率は、いわゆるポジ型のネマティック液晶の誘電率である。なお、ネガ型のネマティック液晶では、棒状分子の長軸方向の誘電率と、棒状分子の長軸方向に垂直な方向の誘電率と、がポジ型のネマティック液晶に対して凡そ逆転する関係になる。 The liquid crystal 15 used in the present disclosure is a nematic liquid crystal in which liquid crystal molecules are rod-shaped. In FIG. 2, ε || indicates the permittivity in the long axis direction of the rod-like molecule, and ε ⊥ indicates the permittivity in the direction perpendicular to the long axis direction of the rod-like molecule. That is, the dielectric constant shown in FIG. 2 is the dielectric constant of a so-called positive nematic liquid crystal. In the negative type nematic liquid crystal, the dielectric constant in the long axis direction of the rod-shaped molecules and the dielectric constant in the direction perpendicular to the long axis direction of the rod-shaped molecules have a relationship that is almost reversed to that of the positive type nematic liquid crystal. .
　図３は、等方性を示す液晶１５が生じていない場合の表示出力と、等方性を示す液晶１５が生じた場合の表示出力との比較を示す模式図である。なお、図３の「状態」では、いわゆる縦電界方式で液晶１５の配向が制御される例を模式的に示している。具体的には、液晶１５が画素電極２１と共通電極２２との間に挟まれる構成例を、図３の「状態」で示している。後述する図４、図１６で例示するように、液晶１５の配向制御のための画素電極２１と共通電極２２の配置例は、いわゆる縦電界方式に限定されるものでなく、適宜変更可能である。 FIG. 3 is a schematic diagram showing a comparison between the display output when the isotropic liquid crystal 15 is not generated and the display output when the isotropic liquid crystal 15 is generated. Note that the "state" in FIG. 3 schematically shows an example in which the orientation of the liquid crystal 15 is controlled by a so-called vertical electric field method. Specifically, a configuration example in which the liquid crystal 15 is sandwiched between the pixel electrode 21 and the common electrode 22 is shown by "State" in FIG. As exemplified in FIGS. 4 and 16 to be described later, the arrangement example of the pixel electrode 21 and the common electrode 22 for controlling the alignment of the liquid crystal 15 is not limited to the so-called vertical electric field method, and can be changed as appropriate. .
　等方性が「無」の「状態」では、液晶１５に含まれる複数の液晶分子の配向に規則性があり、ほぼ同じ配向になるよう制御されている。これは、画素電極２１と共通電極２２との電位差に応じた液晶１５の応答（配向制御）が問題なく成立していることを示している。従って、等方性が「無」の「表示態様例」で例示する通り、液晶表示装置１０の表示パネルＰが有する表示領域ＡＡ（図４等参照）における画像の表示態様は、表示パネルＰへ入力された画像に対応したものになる。 In the "state" where the isotropy is "absent", the alignment of the multiple liquid crystal molecules contained in the liquid crystal 15 has regularity and is controlled to be almost the same. This indicates that the response (orientation control) of the liquid crystal 15 according to the potential difference between the pixel electrode 21 and the common electrode 22 is established without any problem. Therefore, as illustrated in the “example of display mode” where the isotropy is “no”, the display mode of the image in the display area AA (see FIG. 4 etc.) of the display panel P of the liquid crystal display device 10 is correspond to the input image.
　一方、等方性が「有」の「状態」では、液晶１５に含まれる複数の液晶分子の配向に規則性がない状態になっている。これは、画素電極２１と共通電極２２との電位差に応じた液晶１５の応答に異常が生じ、意図された通りの配向制御が成立しなくなっていることを示している。従って、等方性が「有」の「表示態様例」で例示する通り、液晶表示装置１０の表示パネルＰが有する表示領域ＡＡ（図４等参照）における画像の表示態様は、表示パネルＰへ入力された画像に対応したものと異なり、配向制御が成立しない箇所で画像が形成されない又は形成されても非常に視認困難な状態となっていることを示している。このように配向制御が成立しない箇所は、表示領域ＡＡ内のホットスポットＨＳで生じる。当該ホットスポットＨＳは、例えば上述の太陽光の熱による影響で生じる。 On the other hand, in the "state" where the isotropy is "yes", the alignment of the plurality of liquid crystal molecules contained in the liquid crystal 15 is not regular. This indicates that an abnormality occurs in the response of the liquid crystal 15 according to the potential difference between the pixel electrode 21 and the common electrode 22, and the intended orientation control is no longer established. Therefore, as illustrated in the “example of display mode” where the isotropy is “yes”, the display mode of the image in the display area AA (see FIG. 4 etc.) of the display panel P of the liquid crystal display device 10 is Unlike the image corresponding to the input image, the image is not formed at the location where the orientation control is not established, or it is very difficult to visually recognize the image even if it is formed. Locations where alignment control is not established in this way occur at hot spots HS within the display area AA. The hot spot HS is caused, for example, by the heat of the sunlight described above.
　上述のように、液晶１５が等方性を示す状態である場合、通常使用時よりも温度が上昇している。従って、表示パネルＰの温度を検出することで、液晶１５が等方性を示す状態になる兆候を示しているか又は液晶１５が等方性を示す状態に既になっているかを判定することができる。液晶表示装置１０は、表示パネルＰの温度状態を検出する仕組みを有する。ここでいう温度状態の検出とは、例えば、ホットスポットＨＳの検出ように、表示パネルＰの動作に影響を与える温度の発生を検出することをさす。 As described above, when the liquid crystal 15 is isotropic, the temperature is higher than during normal use. Therefore, by detecting the temperature of the display panel P, it is possible to determine whether the liquid crystal 15 is showing signs of becoming isotropic or whether the liquid crystal 15 is already isotropic. . The liquid crystal display device 10 has a mechanism for detecting the temperature state of the display panel P. FIG. The detection of the temperature state here refers to detection of occurrence of temperature that affects the operation of the display panel P, such as detection of a hot spot HS.
　図４は、表示パネルＰの温度状態を検出する原理を示す模式図である。表示パネルＰは、アレイ基板１１と、対向基板１２と、を有する。液晶１５は、アレイ基板１１と対向基板１２との間に挟まれている。以下、アレイ基板１１及び対向基板１２の板面に沿う二方向を第１方向Ｄｘ、第２方向Ｄｙとする。第１方向Ｄｘと第２方向Ｄｙとは直交する。また、第１方向Ｄｘ及び第２方向Ｄｙに直交する方向を第３方向Ｄｚとする。液晶１５を挟んで対向するアレイ基板１１と対向基板１２との対向方向は、第３方向Ｄｚである。図４では図示しないが、液晶１５を挟んで対向するアレイ基板１１及び対向基板１２の第１方向Ｄｘの両端及び第２方向Ｄｙの両端は、シール材２８（図１５参照）で封止されている。 FIG. 4 is a schematic diagram showing the principle of detecting the temperature state of the display panel P. FIG. The display panel P has an array substrate 11 and a counter substrate 12 . Liquid crystal 15 is sandwiched between array substrate 11 and counter substrate 12 . Hereinafter, two directions along the surfaces of the array substrate 11 and the counter substrate 12 are referred to as a first direction Dx and a second direction Dy. The first direction Dx and the second direction Dy are orthogonal. A direction perpendicular to the first direction Dx and the second direction Dy is defined as a third direction Dz. The direction in which the array substrate 11 and the counter substrate 12 face each other with the liquid crystal 15 interposed therebetween is the third direction Dz. Although not shown in FIG. 4, both ends in the first direction Dx and both ends in the second direction Dy of the array substrate 11 and the counter substrate 12 facing each other with the liquid crystal 15 interposed therebetween are sealed with a sealing material 28 (see FIG. 15). there is
　なお、アレイ基板１１、対向基板１２は、透光性を有する素材からなる基板である。具体的には、実施形態におけるアレイ基板１１、対向基板１２は、ガラス基板である。以下、単にガラスと記載した場合、アレイ基板１１及び対向基板１２を構成するガラスをさす。 Note that the array substrate 11 and the counter substrate 12 are substrates made of translucent materials. Specifically, the array substrate 11 and the counter substrate 12 in the embodiment are glass substrates. Hereinafter, when simply referred to as glass, it refers to the glass forming the array substrate 11 and the counter substrate 12 .
　アレイ基板１１には、画素電極２１と共通電極２２が設けられる。画素電極２１は、アレイ基板１１の液晶１５側に設けられ、配向膜５１と当接する。また、液晶１５は、アレイ基板１１側の配向膜５１と対向基板１２側の配向膜５２との間で封止される。配向膜５１及び配向膜５２は、液晶１５に含まれる液晶分子の初期配向を規定する。初期配向は、画素電極２１と共通電極２２との間の電界による影響がない場合における液晶分子の配向である。共通電極２２は、画素電極２１よりもアレイ基板１１側に設けられる。共通電極２２は、層間絶縁膜２７を挟んで画素電極２１と物理的及び電気的に隔てられる。アレイ基板側の積層構造は、画素電極２１、共通電極２２と接続される配線、画素電極２１の電位を制御するためのスイッチング素子等を含む。図４に示す表示パネルＰは、いわゆる横電界方式の液晶表示パネルである。横電界方式では、画素電極２１の電位と共通電極２２の電位との電位差により生じる電界の向きは、基板面（Ｄｘ－Ｄｙ平面）に平行な部分を有する。 A pixel electrode 21 and a common electrode 22 are provided on the array substrate 11 . The pixel electrode 21 is provided on the liquid crystal 15 side of the array substrate 11 and contacts the alignment film 51 . Further, the liquid crystal 15 is sealed between the alignment film 51 on the array substrate 11 side and the alignment film 52 on the counter substrate 12 side. The alignment films 51 and 52 define the initial alignment of liquid crystal molecules contained in the liquid crystal 15 . The initial orientation is the orientation of liquid crystal molecules when there is no effect of the electric field between the pixel electrode 21 and the common electrode 22 . The common electrode 22 is provided closer to the array substrate 11 than the pixel electrode 21 is. The common electrode 22 is physically and electrically separated from the pixel electrode 21 with an interlayer insulating film 27 interposed therebetween. The layered structure on the array substrate side includes pixel electrodes 21, wires connected to the common electrode 22, switching elements for controlling the potential of the pixel electrodes 21, and the like. The display panel P shown in FIG. 4 is a so-called lateral electric field type liquid crystal display panel. In the horizontal electric field method, the direction of the electric field generated by the potential difference between the potential of the pixel electrode 21 and the potential of the common electrode 22 has a portion parallel to the substrate surface (Dx-Dy plane).
　図５は、対向基板１２に設けられたシールド電極２３とアレイ基板１１に設けられた共通電極２２との関係を示す模式的な斜視図である。図４及び図５に示すように、対向基板１２には、シールド電極２３が設けられる。図４に示す表示パネルＰにおけるシールド電極２３は、対向基板１２において、対向基板１２と液晶１５とが対向する面とは反対側の面に設けられる。シールド電極２３は、接地電位（ＧＮＤ）となるよう設けられる。具体的には、シールド電極２３は、外部から延出している接地線又は接地電位（ＧＮＤ）で安定している他の構成に接続されてもよいし、その面積及び膜厚によって実質的にフローティング状態でも接地電位（ＧＮＤ）となる構成であってもよい。 FIG. 5 is a schematic perspective view showing the relationship between the shield electrode 23 provided on the counter substrate 12 and the common electrode 22 provided on the array substrate 11. FIG. As shown in FIGS. 4 and 5, the opposing substrate 12 is provided with a shield electrode 23 . The shield electrode 23 in the display panel P shown in FIG. 4 is provided on the surface of the counter substrate 12 opposite to the surface where the counter substrate 12 and the liquid crystal 15 face each other. The shield electrode 23 is provided to have a ground potential (GND). Specifically, the shield electrode 23 may be connected to a ground line extending from the outside or other configuration that is stable at ground potential (GND), or may be substantially floating due to its area and film thickness. It may be configured to be ground potential (GND) even in the state.
　なお、画素電極２１、共通電極２２及びシールド電極２３は、透光性を有する電極である。具体的には、共通電極２２及びシールド電極２３は、例えばＩＴＯ（Ｉｎｄｉｕｍ　Ｔｉｎ　Ｏｘｉｄｅ）を利用して形成された透光性を示す薄膜電極である。 Note that the pixel electrode 21, the common electrode 22, and the shield electrode 23 are electrodes having translucency. Specifically, the common electrode 22 and the shield electrode 23 are light-transmitting thin-film electrodes formed using, for example, ITO (Indium Tin Oxide).
　シールド電極２３は、平面視点で表示領域ＡＡを覆う。平面視点とは、第３方向Ｄｚに直交する平面（Ｄｘ－Ｄｙ平面）を正視する視点である。より具体的には、シールド電極２３は、表示領域ＡＡ全域をカバーするように一様に連続する薄膜状の電極である。 The shield electrode 23 covers the display area AA in plan view. A planar viewpoint is a viewpoint for viewing a plane (Dx-Dy plane) perpendicular to the third direction Dz. More specifically, the shield electrode 23 is a thin-film electrode that is uniformly continuous so as to cover the entire display area AA.
　一方、アレイ基板１１に設けられた共通電極２２は、図４及び図５に示すように、表示領域ＡＡ内にタイル状に並べられて設けられる。複数の共通電極２２は、各々が表示領域ＡＡの一部分をカバーする。各共通電極２２の表示領域ＡＡ内における位置は異なる。 On the other hand, as shown in FIGS. 4 and 5, the common electrodes 22 provided on the array substrate 11 are arranged in tiles within the display area AA. A plurality of common electrodes 22 each cover a portion of the display area AA. The positions of the common electrodes 22 within the display area AA are different.
　共通電極２２とシールド電極２３がそれぞれ電位を有することにより、これらの間には静電容量が生じる。共通電極２２とシールド電極２３との間の静電容量は、共通電極２２とシールド電極２３との間の構成の比誘電率に対応する。特に、図４に示す構成の場合、共通電極２２とシールド電極２３との間に位置する対向基板１２の比誘電率と、液晶層１５の比誘電率と、が大部分を占める。図４及び後述する図１３では、共通電極２２とシールド電極２３との間の静電容量のうち、対向基板１２の比誘電率に応じて生じる静電容量をＣＧｌａｓｓとして図示している。また、図４及び後述する図１６では、共通電極２２とシールド電極２３との間の静電容量のうち、液晶１５の比誘電率に応じて生じる静電容量をＣＬＣとして図示している。 Since the common electrode 22 and the shield electrode 23 each have a potential, a capacitance is generated between them. The capacitance between common electrode 22 and shield electrode 23 corresponds to the dielectric constant of the structure between common electrode 22 and shield electrode 23 . In particular, in the case of the configuration shown in FIG. 4, the relative permittivity of the counter substrate 12 located between the common electrode 22 and the shield electrode 23 and the relative permittivity of the liquid crystal layer 15 occupy the majority. In FIG. 4 and FIG. 13, which will be described later, the capacitance generated according to the dielectric constant of the counter substrate 12 among the capacitances between the common electrode 22 and the shield electrode 23 is illustrated as C Glass . In FIG. 4 and FIG. 16, which will be described later, the capacitance generated according to the dielectric constant of the liquid crystal 15 among the capacitances between the common electrode 22 and the shield electrode 23 is shown as CLC .
　複数の共通電極２２の各々は、個別にシールド電極２３との間に静電容量を蓄える。また、複数の共通電極２２の各々の表示領域ＡＡ内における位置は異なる。そして、当該静電容量に影響を与える対向基板１２、液晶１５等の共通電極２２とシールド電極２３との間の構成の比誘電率は、当該構成の温度によって変化する。従って、複数の共通電極２２の各々がシールド電極２３との間に蓄える静電容量は、表示パネルＰの表示領域ＡＡ内における各位置の温度によって変化する。 Each of the plurality of common electrodes 22 individually stores capacitance between itself and the shield electrode 23 . Also, the positions of the plurality of common electrodes 22 within the display area AA are different. The dielectric constant of the structure between the common electrode 22 such as the counter substrate 12 and the liquid crystal 15 and the shield electrode 23, which affects the capacitance, changes depending on the temperature of the structure. Therefore, the capacitance stored between each of the plurality of common electrodes 22 and the shield electrode 23 changes depending on the temperature at each position within the display area AA of the display panel P. FIG.
　より具体的には、図４及び図５に示すように、複数の共通電極２２の各々は矩形状の薄膜電極として設けられるので、複数の共通電極２２の各々が設けられる領域は、表示パネルＰの表示領域ＡＡ内における部分領域とみなすことができる。図４では、表示領域ＡＡ内で他のよりも相対的に温度が高くなっている部分領域をホットスポットＨＳとして模式的に図示している。 More specifically, as shown in FIGS. 4 and 5, each of the plurality of common electrodes 22 is provided as a rectangular thin film electrode. can be regarded as a partial area within the display area AA of . In FIG. 4, a partial area within the display area AA whose temperature is relatively higher than other areas is schematically illustrated as a hot spot HS.
　各共通電極２２とシールド電極２３との間に生じた静電容量を検出することで、各共通電極２２が設けられた部分領域毎の温度状態を検出できる。また、共通電極２２は、当該静電容量の検出による温度状態の検出だけでなく、画素電極２１との間の電位差による液晶１５の配向制御にも利用される。液晶１５の配向制御時、すなわち、画像表示時における共通電極２２は、予め定められた電位になるよう制御される。実施形態では、画像表示時と、温度状態の検出時と、で共通電極２２の電気的接続状態を切り替える仕組みが設けられている。 By detecting the capacitance generated between each common electrode 22 and the shield electrode 23, the temperature state of each partial region where each common electrode 22 is provided can be detected. Further, the common electrode 22 is used not only for detecting the temperature state by detecting the capacitance, but also for orientation control of the liquid crystal 15 by the potential difference between the common electrode 22 and the pixel electrode 21 . During alignment control of the liquid crystal 15, that is, during image display, the common electrode 22 is controlled to have a predetermined potential. In the embodiment, a mechanism is provided to switch the electrical connection state of the common electrode 22 between when an image is displayed and when the temperature state is detected.
　図６は、平面視点での画素電極２１と共通電極２２との位置関係及び共通電極２２に接続される構成を示す模式図である。図５及び図６に示すように、複数の共通電極２２は、平面視点でマトリクス状に配置される。各共通電極２２は、それぞれ個別の配線を介してスイッチＳＷと接続される。 FIG. 6 is a schematic diagram showing the positional relationship between the pixel electrode 21 and the common electrode 22 and the configuration connected to the common electrode 22 from a plan view. As shown in FIGS. 5 and 6, the plurality of common electrodes 22 are arranged in a matrix when viewed from above. Each common electrode 22 is connected to the switch SW via an individual wiring.
　図６では、平面視点で３×４＝１２の共通電極２２がマトリクス状に配置され、これらの共通電極２２が配線Ｌ００，Ｌ０１，Ｌ０２，Ｌ０３，Ｌ０４，Ｌ０５，Ｌ０６，Ｌ０７，Ｌ０８，Ｌ０９，Ｌ１０，Ｌ１１を介して個別にスイッチＳＷと接続されている構成例を示しているが、これはあくまで模式的なものであって実際の表示パネルＰにおける共通電極２２の数及び配置を限定するものでない。共通電極２２の数、配置、形状その他の具体的形態は適宜変更可能である。 In FIG. 6, 3×4=12 common electrodes 22 are arranged in a matrix from a plan view, and these common electrodes 22 are interconnects L00, L01, L02, L03, L04, L05, L06, L07, L08, L09, A configuration example in which the switches SW are individually connected via L10 and L11 is shown, but this is only a schematic and limits the number and arrangement of the common electrodes 22 in the actual display panel P. not. The number, arrangement, shape and other specific forms of the common electrodes 22 can be changed as appropriate.
　スイッチＳＷは、画像表示時に共通電極２２と接続される構成と、温度状態の検出時に共通電極２２と接続される構成と、を切り替える。具体的には、スイッチＳＷは、画像表示時に共通電極２２と共通電位線ＶＣＯＭとを接続する。共通電位線ＶＣＯＭの電位は、例えばある電位に固定した固定電位や接地電位（ＧＮＤ）が採用可能であるし、また、所定の周期で振られるパルス波や交流波も採用可能である。もちろんこれに限られるものでなく、画像表示に適した電位であればよく、適宜変更可能である。 The switch SW switches between a configuration in which it is connected to the common electrode 22 during image display and a configuration in which it is connected to the common electrode 22 during temperature state detection. Specifically, the switch SW connects the common electrode 22 and the common potential line VCOM during image display. For the potential of the common potential line VCOM, for example, a fixed potential fixed to a certain potential or a ground potential (GND) can be adopted, and a pulse wave or an AC wave that oscillates at a predetermined cycle can also be adopted. Of course, the potential is not limited to this, and any potential suitable for image display can be used and can be changed as appropriate.
　なお、画像表示時の共通電極２２は、複数の画素電極２１で共有可能である。図６では、平面視点で１つの共通電極２２が設けられた領域内に２×２＝４の画素電極２１が設けられている構成例を示しているが、これはあくまで模式的なものであって実際の表示パネルＰにおける画素電極２１と共通電極２２との関係を限定するものでない。１つの共通電極２２に対する画素電極２１の数、配置、形状その他の具体的形態は適宜変更可能である。 It should be noted that the common electrode 22 during image display can be shared by a plurality of pixel electrodes 21 . FIG. 6 shows a configuration example in which 2×2=4 pixel electrodes 21 are provided in a region in which one common electrode 22 is provided from a plan view, but this is only a schematic. However, the relation between the pixel electrode 21 and the common electrode 22 in the actual display panel P is not limited. The number, arrangement, shape and other specific forms of the pixel electrodes 21 for one common electrode 22 can be changed as appropriate.
　また、スイッチＳＷは、温度状態の検出時に共通電極２２とＡＦＥＩＣ（Ａｎａｒｏｇ　Ｆｒｏｎｔ　Ｅｎｄ　Ｉｎｔｅｇｒａｔｅｄ　Ｃｉｒｃｕｉｔ）３１とを接続する。具体的には、ＡＦＥＩＣ３１は、配線Ｌ００，Ｌ０１，…，Ｌ１１の数に対応した端子Ｒｘ００，Ｒｘ０１，Ｒｘ０２，Ｒｘ０３，Ｒｘ０４，Ｒｘ０５，Ｒｘ０６，Ｒｘ０７，Ｒｘ０８，Ｒｘ０９，Ｒｘ１０，Ｒｘ１１を有する。スイッチＳＷは、温度状態の検出時に、配線Ｌ００，Ｌ０１，…，Ｌ１１と、端子Ｒｘ００，Ｌ０１，…，Ｌ１１と、を個別に接続する。図６では、配線Ｌ００，Ｌ０１，…，Ｌ１１の符号の末尾に付された数値と、端子Ｒｘ００，Ｌ０１，…，Ｌ１１の符号の末尾に付された数値と、が同一であるもの同士が個別に接続可能となるよう設けられている。 Also, the switch SW connects the common electrode 22 and the AFEIC (Analog Front End Integrated Circuit) 31 when the temperature state is detected. Specifically, the AFEIC 31 has terminals Rx00, Rx01, Rx02, Rx03, Rx04, Rx05, Rx06, Rx07, Rx08, Rx09, Rx10, Rx11 corresponding to the number of wirings L00, L01, . The switches SW individually connect the wirings L00, L01, . . . , L11 and the terminals Rx00, L01, . 6, the numbers attached to the ends of the symbols of the wirings L00, L01, . It is provided so that it can be connected to
　図７は、液晶表示装置１０の主要構成例を示すブロック図である。液晶表示装置１０は、表示パネルＰと、制御部３０とを備える。制御部３０は、ＡＦＥＩＣ３１と、ホストコントローラ３２と、ＨＵＤコントローラ３３とを含む。ＡＦＥＩＣ３１は、温度状態の検出時に、配線Ｌ００，Ｌ０１，…，Ｌ１１及び端子Ｒｘ００，Ｌ０１，…，Ｌ１１を介して複数の共通電極２２と個別に接続され、複数の共通電極２２とシールド電極２３との間で生じた静電容量に対応した電気的信号を複数の共通電極２２から個別に取得する回路である。ホストコントローラ３２は、ＡＦＥＩＣ３１と接続される回路である。ホストコントローラ３２は、ＡＦＥＩＣ３１が取得した電気的信号に基づいて、複数の共通電極２２の各々の配置に対応した表示パネルＰの各部分領域の温度状態を特定する。ＨＵＤコントローラ３３は、ホストコントローラ３２と接続される回路である。ＨＵＤコントローラ３３は、ホストコントローラ３２が特定した表示パネルＰの各部分領域の温度状態に基づいて、表示パネルＰの動作を制御する。 FIG. 7 is a block diagram showing a main configuration example of the liquid crystal display device 10. As shown in FIG. The liquid crystal display device 10 includes a display panel P and a control section 30 . The control unit 30 includes an AFEIC 31 , a host controller 32 and a HUD controller 33 . , L11 and terminals Rx00, L01, . . . , L11. It is a circuit that individually acquires from a plurality of common electrodes 22 electrical signals corresponding to the electrostatic capacitances generated between. The host controller 32 is a circuit connected with the AFEIC 31 . The host controller 32 identifies the temperature state of each partial region of the display panel P corresponding to the arrangement of each of the plurality of common electrodes 22 based on the electrical signal acquired by the AFEIC 31 . The HUD controller 33 is a circuit connected with the host controller 32 . The HUD controller 33 controls the operation of the display panel P based on the temperature state of each partial area of the display panel P specified by the host controller 32 .
　制御部３０に含まれる回路は、アレイ基板１１に直接実装されてもよいし、アレイ基板１１から延出するようアレイ基板１１に接続されたフレキシブルプリント基板等、アレイ基板１１との電気的接続を有するアレイ基板１１以外の構成に実装されてもよい。当該フレキシブルプリント基板は、少なくとも、アレイ基板１１に設けられた配線Ｌ００，Ｌ０１，…，Ｌ１１と個別に接続された複数の配線を含む。 The circuits included in the control unit 30 may be directly mounted on the array substrate 11, or may be electrically connected to the array substrate 11, such as a flexible printed substrate connected to the array substrate 11 so as to extend from the array substrate 11. It may be mounted in a configuration other than the array substrate 11 having. The flexible printed board includes at least a plurality of wirings individually connected to the wirings L00, L01, .
　なお、ＡＦＥＩＣ３１が取得する電気的信号は、アナログ信号である。一方、実施形態では、ホストコントローラ３２及びＨＵＤコントローラ３３の処理は、デジタル処理である。従って、図示しないが、当該電気的信号をデジタル信号に変換するアナログ／デジタル変換（ＡＤＣ：Ａｎａｒｏｇ　Ｄｉｇｉｔａｌ　Ｃｏｎｖｅｒｔ）部が制御部３０に設けられる。ＡＤＣ部は、ＡＦＥＩＣ３１内、ホストコントローラ３２内又はＡＦＥＩＣ３１とホストコントローラ３２との間の独立した構成として設けられる。ＡＤＣ後データと記載した場合、ＡＤＣ部によって電気的信号をデジタルデータに変換したものをさす。 The electrical signal acquired by the AFEIC 31 is an analog signal. On the other hand, in the embodiment, the processing of the host controller 32 and the HUD controller 33 are digital processing. Therefore, although not shown, the controller 30 is provided with an analog/digital converter (ADC) that converts the electrical signal into a digital signal. The ADC unit is provided within the AFEIC 31 , within the host controller 32 , or as an independent configuration between the AFEIC 31 and the host controller 32 . When described as post-ADC data, it refers to data obtained by converting an electrical signal into digital data by the ADC section.
　以下、ホストコントローラ３２による温度状態の特定の仕組みについて、図８から図１０を参照して説明する。 The mechanism for specifying the temperature state by the host controller 32 will be described below with reference to FIGS. 8 to 10. FIG.
　図８は、ガラスと液晶１５の誘電率温度特性を示すグラフである。図８に示すように、ガラスは、温度の上昇に比例するように比誘電率が高まる。一方、液晶１５は、８０度（℃）と１００度（℃）の間に、温度の上昇に対する比誘電率の高まりが他の温度帯に比して急激に大きくなる相転移温度帯ＰＴ１が含まれている。上述のＴｃ（図２参照）は、当該相転移温度帯ＰＴ１の温度である。なお、液晶１５は、相転移温度帯ＰＴ１以外の温度帯では温度の上昇に比例するように比誘電率が高まる。 FIG. 8 is a graph showing dielectric constant temperature characteristics of glass and liquid crystal 15. In FIG. As shown in FIG. 8, the relative permittivity of glass increases in proportion to the increase in temperature. On the other hand, the liquid crystal 15 includes a phase transition temperature zone PT1 between 80 degrees (° C.) and 100 degrees (° C.), in which the increase in the relative permittivity with respect to the temperature rise is sharper than in the other temperature zones. is The aforementioned T c (see FIG. 2) is the temperature of the phase transition temperature zone PT1. In addition, the liquid crystal 15 has a relative permittivity that increases in proportion to temperature rise in a temperature range other than the phase transition temperature range PT1.
　図９は、図８に示す誘電率温度特性を示すガラスと液晶１５が採用された表示パネルＰの温度と当該表示パネルＰにおける共通電極２２とシールド電極２３との間の静電容量との関係を示すグラフである。 FIG. 9 shows the relationship between the temperature of the display panel P employing the glass and liquid crystal 15 exhibiting the dielectric constant-temperature characteristics shown in FIG. 8 and the capacitance between the common electrode 22 and the shield electrode 23 in the display panel P. is a graph showing
　図４に示す表示パネルＰの構成のように、共通電極２２とシールド電極２３との間に対向基板１２及び液晶１５がある場合、共通電極２２とシールド電極２３との間に、対向基板１２の素材であるガラスと、液晶１５と、が存在することになる。この場合、共通電極２２とシールド電極２３との間の静電容量は、ガラスの比誘電率と、液晶１５の比誘電率と、の影響を受ける。図８を参照して説明したように、ガラスの比誘電率は温度の変化に比例した変化を示すが、液晶１５の比誘電率の変化パターンは相転移温度帯ＰＴ１を含む。このため、図４に示す表示パネルＰの構成では、図９の「ガラス＋液晶」に示すように、温度の上昇に対する静電容量の高まりが他の温度帯に比して急激に大きくなる温度帯ＰＴ２がある。温度帯ＰＴ２は、相転移温度帯ＰＴ１の温度帯に対応する。なお、共通電極２２とシールド電極２３との間の静電容量は、温度帯ＰＴ２以外の温度帯では温度の上昇に比例するように静電容量が高まる。 When the counter substrate 12 and the liquid crystal 15 are between the common electrode 22 and the shield electrode 23 as in the configuration of the display panel P shown in FIG. Glass as a material and the liquid crystal 15 are present. In this case, the capacitance between the common electrode 22 and the shield electrode 23 is affected by the dielectric constant of the glass and the dielectric constant of the liquid crystal 15 . As described with reference to FIG. 8, the relative dielectric constant of glass exhibits a change proportional to the change in temperature, and the variation pattern of the relative dielectric constant of the liquid crystal 15 includes the phase transition temperature zone PT1. For this reason, in the configuration of the display panel P shown in FIG. 4, as shown in "glass + liquid crystal" in FIG. There is band PT2. The temperature zone PT2 corresponds to the temperature zone of the phase transition temperature zone PT1. It should be noted that the capacitance between the common electrode 22 and the shield electrode 23 increases in proportion to the rise in temperature in a temperature zone other than the temperature zone PT2.
　図１０は、図９に示す温度と静電容量との関係に対応した、温度とＡＤＣ後データが示す数値との関係を示すグラフである。上述のように、ＡＦＥＩＣ３１は、共通電極２２とシールド電極２３との間の静電容量に応じた電気的信号を取得する。当該電気的信号は、ＡＤＣ部によってＡＤＣ後データに変換される。当該ＡＤＣ後データは、共通電極２２とシールド電極２３との間の静電エネルギーの大きさに対応した電気的信号の強さを示す数値データである。従って、ＡＤＣデータが示す数値と温度との関係は、図９を参照して説明した静電容量と温度との関係と同様の関係になる。具体的には、図１０に示すように、温度の上昇に対するＡＤＣデータが示す数値の上昇が他の温度帯に比して急激に大きくなる温度帯ＰＴ３がある。温度帯ＰＴ３は、相転移温度帯ＰＴ１及び温度帯ＰＴ２の温度帯に対応する。なお、ＡＤＣデータが示す数値は、温度帯ＰＴ３以外の温度帯では温度の上昇に比例するように上昇する。 FIG. 10 is a graph showing the relationship between temperature and numerical value indicated by post-ADC data, corresponding to the relationship between temperature and capacitance shown in FIG. As described above, the AFEIC 31 acquires electrical signals corresponding to the capacitance between the common electrode 22 and the shield electrode 23. FIG. The electrical signal is converted into post-ADC data by the ADC section. The post-ADC data is numerical data indicating the strength of the electrical signal corresponding to the magnitude of the electrostatic energy between the common electrode 22 and the shield electrode 23 . Therefore, the relationship between the numerical value indicated by the ADC data and the temperature is the same as the relationship between the capacitance and the temperature described with reference to FIG. Specifically, as shown in FIG. 10, there is a temperature zone PT3 in which the increase in numerical value indicated by the ADC data with respect to the temperature rise is sharper than in the other temperature zones. The temperature zone PT3 corresponds to the temperature zones of the phase transition temperature zone PT1 and the temperature zone PT2. Note that the numerical value indicated by the ADC data increases in proportion to the increase in temperature in temperature zones other than the temperature zone PT3.
　そこで、温度帯ＰＴ３の下限温度に対応するＡＤＣ後データの値ＢＬを基準として、ホストコントローラ３２による温度状態の検出及びＨＵＤコントローラ３３による表示パネルＰの動作制御の具体的内容を決定することで、太陽光による表示パネルＰの温度上昇に適切に対応できる。 Therefore, by determining the specific contents of the detection of the temperature state by the host controller 32 and the operation control of the display panel P by the HUD controller 33 based on the post-ADC data value BL corresponding to the lower limit temperature of the temperature zone PT3, It is possible to appropriately cope with the temperature rise of the display panel P due to sunlight.
　例えば、値ＢＬ未満のＡＤＣ後データの値ＴＬ１になった場合にＰＬにホットスポットＨＳが生じる兆候があるものとして扱ってもよい。この場合、ＡＤＣ後データの値ＴＬ１が得られた時点で、そのことを示す出力をホストコントローラ３２が行う。ＨＵＤコントローラ３３は、当該出力に応じて表示パネルＰの動作を停止させる。これによって、図３を参照して説明したホットスポットＨＳのような、液晶１５の配向制御が成立しない箇所が生じている状態での表示出力が行われることを抑制できる。 For example, if the post-ADC data value TL1 is less than the value BL, it may be treated as a sign that a hot spot HS will occur in PL. In this case, when the post-ADC data value TL1 is obtained, the host controller 32 outputs an output indicating that fact. The HUD controller 33 stops the operation of the display panel P according to the output. As a result, it is possible to prevent the display output from being performed in a state where the orientation control of the liquid crystal 15 is not established, such as the hot spot HS described with reference to FIG.
　また、値ＢＬと同値又は値ＢＬ以上のＡＤＣ後データの値ＴＬ２になった場合、表示パネルＰにホットスポットＨＳが生じているものとして扱ってもよい。この場合、ＡＤＣ後データの値として値ＢＬ又は値ＴＬ２が得られた時点で、そのことを示す出力をホストコントローラ３２が行う。ＨＵＤコントローラ３３は、当該出力に応じて表示パネルＰの動作を停止させる。これによって、図３を参照して説明したホットスポットＨＳのような、液晶１５の配向制御が成立しない箇所が生じている状態での表示出力が継続して行われることを抑制できる。また、値ＴＬ２が得られたということは、温度帯ＰＴ３における「温度の上昇に対するＡＤＣデータが示す数値の上昇が他の温度帯に比して急激に大きくなる」状態を経ていることを示す。従って、このようなＡＤＣ後データの値の有意な上昇を以て、ホットスポットＨＳが生じている可能性がより高いことの裏付けを得た状態で表示パネルＰの動作が決定されるようにできる。 Also, when the post-ADC data value TL2 equals or exceeds the value BL, it may be assumed that the display panel P has a hot spot HS. In this case, when the value BL or the value TL2 is obtained as the post-ADC data value, the host controller 32 outputs an output indicating that fact. The HUD controller 33 stops the operation of the display panel P according to the output. As a result, it is possible to prevent display output from being continued in a state where alignment control of the liquid crystal 15 is not established, such as the hot spot HS described with reference to FIG. Also, the fact that the value TL2 was obtained indicates that the temperature zone PT3 has undergone a state in which "the increase in the numerical value indicated by the ADC data with respect to the rise in temperature increases rapidly compared to other temperature zones". Therefore, with such a significant increase in the post-ADC data value, the operation of the display panel P can be determined with confirmation that the hotspot HS is more likely to occur.
　なお、上述の説明では、ＡＤＣ後データの値に基づいてホストコントローラ３２が出力を行っているが、ホストコントローラ３２は、ＡＤＣ後データの値に対応する表示パネルＰの温度を特定し、特定された温度が所定温度以上である場合にそのことを示す出力を行う構成であってもよい。その場合、ホストコントローラ３２は、ＡＤＣ後データの値と表示パネルＰの温度との対応関係を示すデータを保持する回路又は当該データを記憶する外部の構成から当該データを参照する機能を有する回路である。 In the above description, the host controller 32 performs output based on the value of post-ADC data, but the host controller 32 specifies the temperature of the display panel P corresponding to the value of the post-ADC data, and The configuration may be such that when the temperature obtained is equal to or higher than a predetermined temperature, an output indicating that fact is made. In that case, the host controller 32 is a circuit that holds data indicating the correspondence between the value of post-ADC data and the temperature of the display panel P, or a circuit that has a function of referring to the data from an external configuration that stores the data. be.
　ところで、表示パネルＰに対して意図せず外部の構成が近接又は接触した場合、共通電極２２とシールド電極２３との間の静電容量に影響が生じる場合がある。この影響は、共通電極２２とシールド電極２３との間で蓄えられた静電エネルギーにより生じる電界がシールド電極２３側の外側まで及び、かつ、当該電界内に意図せず外部の構成が近接又は接触した場合に生じる。この影響によって、共通電極２２とシールド電極２３との間の静電容量に基づいた温度状態の検出精度が低下する虞がある。そこで、液晶表示装置１０では、当該影響を十分に抑制できるシート抵抗を有するシールド電極２３を採用している。具体的には、シールド電極２３のシート抵抗は、１０４Ω／□以下である。また、シールド電極２３は、表示領域ＡＡを覆う薄膜状である。すなわち、平面視点で共通電極２２側から見た場合、シールド電極２３には開口部がない。これによって、共通電極２２とシールド電極２３との間で蓄えられた静電エネルギーにより生じる電界がシールド電極２３側の外側まで及ぶことによる当該影響を十分に抑制できる。 By the way, when an external component unintentionally approaches or touches the display panel P, the capacitance between the common electrode 22 and the shield electrode 23 may be affected. This effect is due to the fact that the electric field generated by the electrostatic energy stored between the common electrode 22 and the shield electrode 23 extends to the outside of the shield electrode 23 side, and that an external structure is unintentionally brought into proximity or contact with the electric field. occurs when Due to this influence, there is a possibility that the detection accuracy of the temperature state based on the electrostatic capacitance between the common electrode 22 and the shield electrode 23 is lowered. Therefore, the liquid crystal display device 10 employs the shield electrode 23 having a sheet resistance that can sufficiently suppress the influence. Specifically, the sheet resistance of the shield electrode 23 is 10 4 Ω/□ or less. Also, the shield electrode 23 is a thin film covering the display area AA. That is, when viewed from the common electrode 22 side in a plan view, the shield electrode 23 has no opening. This can sufficiently suppress the influence of the electric field generated by the electrostatic energy stored between the common electrode 22 and the shield electrode 23 extending to the outside of the shield electrode 23 side.
　なお、図８は、真空の誘電率が８．８５×１０－１２Ｆ／ｍ（＝８．８５ｐＦ）であるものとして求められた比誘電率を示している。また、図６から図８に示すグラフに対応する結果が得られた表示パネルＰにおいて、アレイ基板１１と対向基板１２との間に封止される液晶１５の層（液晶層）の第３方向Ｄｚの厚みは、３．０μｍである。また、図６から図８に示すグラフに対応する結果が得られた表示パネルＰにおいて、対向基板１２の第３方向Ｄｚの厚みは、２００．０μｍである。また、ＡＤＣ部の分解能、すなわち、ＡＤＣ部が認識可能な入力（静電容量）の最小単位は、例えば１０ｐｆである。また、ＡＤＣ後データは、例えば１２ビットである。これらの諸元はあくまで一例であってこれに限られるものでなく、適宜変更可能である。 It should be noted that FIG. 8 shows relative dielectric constants obtained assuming that the vacuum dielectric constant is 8.85×10 −12 F/m (=8.85 pF). In addition, in the display panel P for which results corresponding to the graphs shown in FIGS. The thickness of Dz is 3.0 μm. In the display panel P for which results corresponding to the graphs shown in FIGS. 6 to 8 were obtained, the thickness of the counter substrate 12 in the third direction Dz was 200.0 μm. Further, the resolution of the ADC section, that is, the minimum unit of input (capacitance) that can be recognized by the ADC section is, for example, 10 pf. Further, the post-ADC data is, for example, 12 bits. These specifications are merely examples and are not limited to these, and can be changed as appropriate.
　表示パネルＰでは、入力される画像信号に応じたフレーム画像の表示出力の周期的な更新が行われる。当該更新のフレームレートは、例えば６０Ｈｚ、１２０Ｈｚ又は２４０Ｈｚであるが、これらに限られるものでなく、適宜変更可能である。ここで、当該フレームレートで更新が行われる表示パネルＰにおいて１つのフレーム画像が表示される期間を１フレーム期間とすると、１フレーム期間内に液晶駆動期間と温度検出期間とが含まれることが望ましい。液晶駆動期間とは、画像表示のため、画素電極２１が個別に設けられた表示パネルＰの画素の駆動が行われる期間である。より具体的には、液晶駆動期間とは、複数の画素電極２１の各々の電位が個別に制御され、その電位に応じて各画素で液晶分子が駆動される期間である。液晶駆動期間では、スイッチＳＷが、共通電極２２と定電位線ＶＣＯＭとを接続する。温度検出期間は、液晶表示装置１０で表示パネルＰの温度状態が検出される期間である。温度検出期間では、スイッチＳＷが、共通電極２２とＡＦＥＩＣ３１とを接続する。 The display panel P periodically updates the display output of the frame image according to the input image signal. The update frame rate is, for example, 60 Hz, 120 Hz, or 240 Hz, but is not limited to these and can be changed as appropriate. Here, assuming that the period during which one frame image is displayed on the display panel P updated at the frame rate is one frame period, it is desirable that one frame period includes a liquid crystal drive period and a temperature detection period. . The liquid crystal drive period is a period during which the pixels of the display panel P in which the pixel electrodes 21 are individually provided are driven for image display. More specifically, the liquid crystal drive period is a period in which the potential of each of the plurality of pixel electrodes 21 is individually controlled, and liquid crystal molecules are driven in each pixel according to the potential. During the liquid crystal drive period, the switch SW connects the common electrode 22 and the constant potential line VCOM. The temperature detection period is a period during which the temperature state of the display panel P is detected by the liquid crystal display device 10 . During the temperature detection period, the switch SW connects the common electrode 22 and the AFEIC 31 .
　図１１は、液晶表示装置１０の動作例を示すタイミングチャートである。フレーム期間Ｆ１，Ｆ２，Ｆ３は、それぞれが１フレーム期間である。図１１に示すように、１フレーム期間中に液晶駆動期間と温度検出期間とが１回ずつ生じてもよい。なお、図１１では図示しないが、フレーム期間Ｆ３の後も同様に１フレーム期間中に液晶駆動期間と温度検出期間とが１回ずつ生じるフレーム期間がフレームレートに応じた周期で継続する。 FIG. 11 is a timing chart showing an operation example of the liquid crystal display device 10. FIG. Each of the frame periods F1, F2, and F3 is one frame period. As shown in FIG. 11, one liquid crystal drive period and one temperature detection period may occur during one frame period. Although not shown in FIG. 11, after the frame period F3, a frame period in which one liquid crystal drive period and one temperature detection period occur continues at a cycle corresponding to the frame rate.
　図１２は、図１１に示す例とは異なる液晶表示装置１０の動作例を示すタイミングチャートである。１フレーム期間中に液晶駆動期間と温度検出期間とが複数回生じてもよい。具体的には、例えば図１２に示すように、１フレーム期間中に液晶駆動期間と温度検出期間とが３回ずつ生じてもよい。このように１フレーム期間中に液晶駆動期間が複数回生じる制御方式の具体例として、１つの画素から複数色の光をそれぞれ異なるタイミングで透過させるように画素を制御する所謂フィールドシーケンシャルカラー（ＦＳＣ：Ｆｉｅｌｄ　Ｓｅｑｕｅｎｔｉａｌ　Ｃｏｌｏｒ）方式が挙げられる。図１２に示すように１フレーム期間中に液晶駆動期間が３回生じる場合、３回中の１回で赤（Ｒ）の画像が出力され、他の１回で緑（Ｇ）の画像が出力され、さらに他の１回で青（Ｂ）の画像が出力されることで、カラー画像が出力される。温度検出期間は、１フレーム期間中に複数回生じる液晶駆動期間の各々の後に設定される。なお、図１２では図示しないが、フレーム期間Ｆ１の後も同様に１フレーム期間中に液晶駆動期間と温度検出期間とが交互に複数回生じるフレーム期間がフレームレートに応じた周期で継続する。 FIG. 12 is a timing chart showing an operation example of the liquid crystal display device 10 different from the example shown in FIG. The liquid crystal drive period and the temperature detection period may occur multiple times during one frame period. Specifically, for example, as shown in FIG. 12, the liquid crystal drive period and the temperature detection period may occur three times during one frame period. As a specific example of a control method in which multiple liquid crystal drive periods are generated during one frame period, a so-called field sequential color (FSC) system that controls pixels so that light of a plurality of colors is transmitted from one pixel at different timings. Field Sequential Color) method. As shown in FIG. 12, when the liquid crystal drive period occurs three times in one frame period, a red (R) image is output in one of the three times, and a green (G) image is output in the other one. A color image is output by outputting a blue (B) image at another time. The temperature detection period is set after each liquid crystal drive period that occurs multiple times during one frame period. Although not shown in FIG. 12, even after the frame period F1, a frame period in which the liquid crystal drive period and the temperature detection period alternately occur multiple times continues at a cycle corresponding to the frame rate.
　なお、図１２では、液晶駆動期間の回数と温度検出期間の回数とが同一であるが、これに限られるものでない。すなわち、１フレーム期間中に生じる液晶駆動期間の回数と温度検出期間の回数とが異なっていてもよい。例えば、１フレーム期間中に複数の液晶駆動期間と１回の温度検出期間とが生じてもよい。具体的には、図１１を参照して説明した例では、各温度検出期間で全ての共通電極２２による各部分領域の温度状態の検出を同時に行う一方、図１２を参照して説明した例では、各温度検出期間ごとに複数の共通電極２２のうち１つによる温度状態の検出を行うようにしてもよい。 In FIG. 12, the number of liquid crystal drive periods and the number of temperature detection periods are the same, but the present invention is not limited to this. That is, the number of liquid crystal drive periods and the number of temperature detection periods that occur during one frame period may be different. For example, a plurality of liquid crystal drive periods and one temperature detection period may occur during one frame period. Specifically, in the example described with reference to FIG. 11, the temperature state of each partial region is simultaneously detected by all the common electrodes 22 in each temperature detection period, whereas in the example described with reference to FIG. Alternatively, the temperature state may be detected by one of the plurality of common electrodes 22 for each temperature detection period.
　また、１フレーム期間中における液晶駆動期間と温度検出期間との前後関係は適宜変更可能である。すなわち、温度検出期間の後に液晶駆動期間が生じてもよい。なお、図１１及び図１２においてフレーム期間内で液晶駆動期間でも温度検出期間でもない期間があるが、これは画素電極２１の電位をリセットする等の処理が行われるブランキング期間である。 Also, the sequential relationship between the liquid crystal drive period and the temperature detection period in one frame period can be changed as appropriate. That is, the liquid crystal drive period may occur after the temperature detection period. In FIGS. 11 and 12, there is a period that is neither a liquid crystal drive period nor a temperature detection period within the frame period, but this is a blanking period during which processing such as resetting the potential of the pixel electrode 21 is performed.
　なお、図１１、図１２に示す液晶駆動期間と温度検出期間との切替制御は、例えばＨＵＤコントローラ３３が行うが、他の構成が行ってもよい。例えば、表示パネルＰに設けられて各画素の画素電極２１に与えられる信号を出力するソースドライバ及び各画素のスイッチング素子を順次走査駆動するゲートドライバの動作タイミング制御を行うタイミングコントローラが当該切替制御を行ってもよい。 The switching control between the liquid crystal drive period and the temperature detection period shown in FIGS. 11 and 12 is performed by the HUD controller 33, for example, but may be performed by another configuration. For example, a timing controller that performs operation timing control of a source driver that is provided in the display panel P and outputs a signal to be applied to the pixel electrode 21 of each pixel and a gate driver that sequentially scans and drives the switching element of each pixel performs the switching control. you can go
　以上、図４に示す表示パネルＰを例とした説明を行ってきたが、液晶表示装置１０で採用可能な画素電極２１、共通電極２２、シールド電極２３の位置関係は、図４に示す例に限定されるものでない。 The display panel P shown in FIG. 4 has been described above as an example. It is not limited.
　図１３は、図４とは異なる共通電極２２とシールド電極２３との位置関係でパネルの温度状態を検出する仕組みを示す模式図である。上述の表示パネルＰは、表示パネルＰ２に置換されてもよい。表示パネルＰ２は、図１３に示すように、共通電極２２が対向基板１２に設けられる。図１３に示す表示パネルＰは、いわゆる縦電界方式の液晶表示パネルである。縦電界方式では、画素電極２１の電位と共通電極２２の電位との電位差により生じる電界の向きとアレイ基板１１と対向基板１２との対向方向（第３方向Ｄｚ）とが対応する。なお、当該シールド電極２３に重ねて偏光板（図示省略）を設ける構成も採用することができる。 FIG. 13 is a schematic diagram showing a mechanism for detecting the temperature state of the panel with a positional relationship between the common electrode 22 and the shield electrode 23 different from that in FIG. The display panel P described above may be replaced with a display panel P2. The display panel P2 has a common electrode 22 provided on the counter substrate 12, as shown in FIG. The display panel P shown in FIG. 13 is a so-called vertical electric field type liquid crystal display panel. In the vertical electric field method, the direction of the electric field generated by the potential difference between the potential of the pixel electrode 21 and the potential of the common electrode 22 corresponds to the opposing direction (third direction Dz) between the array substrate 11 and the counter substrate 12 . A configuration in which a polarizing plate (not shown) is provided over the shield electrode 23 can also be adopted.
　図１４は、図１３に示す共通電極２２に接続される構成を示す模式図である。図１５は、図１４における信号伝送経路Ｅｘの断面図である。表示パネルＰ２では、配線Ｌ００，Ｌ０１，…，Ｌ１１が対向基板１２に設けられる。表示パネルＰ２では、共通電極２２と接続される配線を層間膜２７内で完結させられず、アレイ基板１１と対向基板１２との間で信号伝送経路を形成する必要がある。このため、表示パネルＰ２では、信号伝送経路Ｅｘが設けられている。 FIG. 14 is a schematic diagram showing a configuration connected to the common electrode 22 shown in FIG. 15 is a cross-sectional view of the signal transmission path Ex in FIG. 14. FIG. In the display panel P2, wirings L00, L01, . In the display panel P2, the wiring connected to the common electrode 22 cannot be completed within the interlayer film 27, and it is necessary to form a signal transmission path between the array substrate 11 and the counter substrate 12. FIG. Therefore, the signal transmission path Ex is provided in the display panel P2.
　具体的には、図１４に示すように、配線Ｌ００，Ｌ０１，…，Ｌ１１と端子Ｒｘ００，Ｒｘ０１，…，Ｒｘ１１との間に信号伝送経路Ｅｘが設けられている。信号伝送経路Ｅｘは、導通粒子２５と配線２６とを含む。図１５に示すように、導通粒子２５は、アレイ基板１１と対向基板１２との間に位置し、配線Ｌ１１と配線２６との間の電気的接続を成立させる。なお、図１５は、図１４に示す配線Ｌ１１の位置におけるＤｙ－Ｄｚ断面図であるために導通粒子２５と配線Ｌ１１とが接続されているが、配線Ｌ１１以外の配線Ｌ００，Ｌ０１，…，Ｌ１０の位置では、導通粒子２５は、配線２６と配線Ｌ００，Ｌ０１，…，Ｌ１０のいずれかとを接続する。配線２６は、アレイ基板１１側に設けられて端子Ｒｘ００，Ｒｘ０１，…，Ｒｘ１１のいずれかと接続される。図１５では画素電極２１を図示しないが、配線２６は、層間膜２７によって画素電極２１と絶縁される。なお、表示パネルＰ２でも、配線Ｌ００，Ｌ０１，…，Ｌ１１の符号の末尾に付された数値と、端子Ｒｘ００，Ｌ０１，…，Ｌ１１の符号の末尾に付された数値と、が同一であるもの同士が個別に接続される点では表示パネルＰと同様である。 Specifically, as shown in FIG. 14, signal transmission paths Ex are provided between the wirings L00, L01, . . . , L11 and the terminals Rx00, Rx01, . The signal transmission path Ex includes conductive particles 25 and wiring 26 . As shown in FIG. 15, the conductive particles 25 are positioned between the array substrate 11 and the counter substrate 12 and establish an electrical connection between the wiring L11 and the wiring 26. FIG. 15 is a Dy-Dz cross-sectional view at the position of the wiring L11 shown in FIG. 14, so that the conductive particles 25 and the wiring L11 are connected. , the conductive particle 25 connects the wiring 26 with any one of the wirings L00, L01, . . . , L10. The wiring 26 is provided on the side of the array substrate 11 and connected to any one of the terminals Rx00, Rx01, . . . , Rx11. Although the pixel electrode 21 is not shown in FIG. 15, the wiring 26 is insulated from the pixel electrode 21 by the interlayer film 27 . In the display panel P2, the numerical values added to the end of the symbols of the wirings L00, L01, . It is the same as the display panel P in that they are individually connected.
　表示パネルＰ２では、図１３に示すように、共通電極２２とシールド電極２３との間に対向基板１２があり、液晶１５がない。従って、表示パネルＰ２では、共通電極２２とシールド電極２３との間に、対向基板１２の素材であるガラスが存在することになる。この場合、共通電極２２とシールド電極２３との間の静電容量は、ガラスの比誘電率の影響を受け、液晶１５の比誘電率の影響を受けない。図８を参照して説明したように、ガラスの比誘電率は温度の変化に比例した変化を示す。このため、表示パネルＰ２の構成では、図９の「ガラス」に示すように、温度の上昇に比例するように静電容量が高まる。このような表示パネルＰ２では、図１０を参照して説明した温度帯ＰＴ３におけるＡＤＣ後データの相対的に大きな変化を利用した温度状態の検出はできないが、温度の上昇に比例したＡＤＣ後データの上昇は生じる。従って、値ＴＬ１又は値ＴＬ２に基づいた表示パネルＰの動作制御と同様に表示パネルＰ２の動作制御を行える。 In the display panel P2, as shown in FIG. 13, the counter substrate 12 is between the common electrode 22 and the shield electrode 23, and the liquid crystal 15 is not provided. Therefore, in the display panel P2, glass, which is the material of the counter substrate 12, exists between the common electrode 22 and the shield electrode 23. As shown in FIG. In this case, the capacitance between the common electrode 22 and the shield electrode 23 is affected by the dielectric constant of the glass and is not affected by the dielectric constant of the liquid crystal 15 . As described with reference to FIG. 8, the dielectric constant of glass shows a change proportional to the change in temperature. Therefore, in the configuration of the display panel P2, the capacitance increases in proportion to the temperature rise, as indicated by "glass" in FIG. With such a display panel P2, the temperature state cannot be detected using relatively large changes in the post-ADC data in the temperature zone PT3 described with reference to FIG. A rise occurs. Therefore, the operation control of the display panel P2 can be performed in the same manner as the operation control of the display panel P based on the value TL1 or the value TL2.
　図１６は、図４及び図１３とは異なる共通電極２２とシールド電極２３との位置関係でパネルの温度状態を検出する仕組みを示す模式図である。上述の表示パネルＰは、表示パネルＰ３に置換されてもよい。図１６に示す表示パネルＰ３は、シールド電極２３が対向基板１２と液晶１５との間に配置される点で図４に示す表示パネルＰと異なる。従って、表示パネルＰ３では、共通電極２２とシールド電極２３との間に液晶１５があり、対向基板１２がない。この場合、共通電極２２とシールド電極２３との間の静電容量は、液晶１５の比誘電率の影響を受け、ガラスの比誘電率の影響を受けない。それ以外の点では、表示パネルＰ３は、表示パネルＰと同様である。このため、図１６に示す表示パネルＰ３の構成では、表示パネルＰと同様、温度の上昇に対する共通電極２２とシールド電極２３との間の静電容量の高まりが他の温度帯に比して急激に大きくなる温度帯が生じる。このような表示パネルＰ２では、図１０を参照して説明した温度帯ＰＴ３と同様の、ＡＤＣ後データの相対的に大きな変化を利用した温度状態の検出が可能になる。 FIG. 16 is a schematic diagram showing a mechanism for detecting the temperature state of the panel with a positional relationship between the common electrode 22 and the shield electrode 23 different from that shown in FIGS. The display panel P described above may be replaced with a display panel P3. A display panel P3 shown in FIG. 16 differs from the display panel P shown in FIG. Accordingly, in the display panel P3, the liquid crystal 15 is present between the common electrode 22 and the shield electrode 23, and the opposing substrate 12 is absent. In this case, the capacitance between the common electrode 22 and the shield electrode 23 is affected by the dielectric constant of the liquid crystal 15 and is not affected by the dielectric constant of the glass. The display panel P3 is the same as the display panel P in other respects. For this reason, in the configuration of the display panel P3 shown in FIG. 16, similarly to the display panel P, the increase in the capacitance between the common electrode 22 and the shield electrode 23 with respect to temperature rise is more rapid than in other temperature ranges. A temperature band that increases to With such a display panel P2, it is possible to detect the temperature state using relatively large changes in post-ADC data, similar to the temperature zone PT3 described with reference to FIG.
　なお、図１６に示すように、対向基板１２の表示面側には、偏光板６１が設けられる。偏光板６１は、対向基板１２に接着されている。 In addition, as shown in FIG. 16, a polarizing plate 61 is provided on the display surface side of the counter substrate 12 . The polarizing plate 61 is adhered to the opposing substrate 12 .
　以上説明したように、本開示の構成によれば、液晶表示装置１０は、所定方向（第３方向Ｄｚ）に対向する２つの基板（アレイ基板１１、対向基板１２）の間に挟まれた液晶１５の配向を制御して画像を表示する表示領域ＡＡを有する表示パネル（例えば、表示パネルＰ）と、当該表示領域を覆う第１電極（シールド電極２３）と、当該表示領域内のそれぞれ異なる位置に設けられて当該第１電極と当該所定方向に対向する複数の第２電極（共通電極２２）と、当該第１電極と当該複数の第２電極の各々との間の静電容量に基づいて、当該複数の第２電極の各々が位置する領域毎の温度が所定温度以上であるか判定する判定部（ホストコントローラ３２）と、を備える。ここで、所定温度とは、上述のＡＤＣ後データの値が閾値（例えば、値ＴＬ１、値ＢＬ又は値ＴＬ２）となる表示パネルＰの温度をさす。当該第１電極のシート抵抗は、１０４Ω／□以下である。これによって、所定温度を通常動作時の温度よりも著しく高い温度とすることで、当該表示パネルが通常動作時の温度よりも著しく高温になったことを検出できる。 As described above, according to the configuration of the present disclosure, the liquid crystal display device 10 includes liquid crystal sandwiched between two substrates (array substrate 11 and counter substrate 12) facing each other in a predetermined direction (third direction Dz). A display panel (for example, a display panel P) having a display area AA for displaying an image by controlling the orientation of 15, a first electrode (shield electrode 23) covering the display area, and different positions in the display area. Based on the capacitance between a plurality of second electrodes (common electrode 22) provided in and facing the first electrode in the predetermined direction, and the first electrode and each of the plurality of second electrodes and a determination unit (host controller 32) that determines whether the temperature of each region where each of the plurality of second electrodes is located is equal to or higher than a predetermined temperature. Here, the predetermined temperature refers to the temperature of the display panel P at which the value of the post-ADC data becomes a threshold value (for example, the value TL1, the value BL, or the value TL2). The sheet resistance of the first electrode is 10 4 Ω/□ or less. Thus, by setting the predetermined temperature to a temperature significantly higher than the temperature during normal operation, it can be detected that the display panel has become significantly higher than the temperature during normal operation.
　また、判定部（ホストコントローラ３２）が検出した温度が所定温度以上である場合に表示パネル（例えば、表示パネルＰ）の動作を停止させる動作制御部（ＨＵＤコントローラ３３）を備える。これによって、当該表示パネルが通常動作時の温度よりも著しく高温になった場合に当該表示パネルの動作を停止させることができる。従って、入力に対応した画像を正常に出力することができない状態になった可能性のある当該表示パネルが動作を継続してしまう状態の発生を抑制できる。すなわち、当該表示パネルが通常動作時の温度よりも著しく高温になったことによる異常な画像の出力を抑制できる。 It also includes an operation control unit (HUD controller 33) that stops the operation of the display panel (for example, display panel P) when the temperature detected by the determination unit (host controller 32) is equal to or higher than a predetermined temperature. As a result, the operation of the display panel can be stopped when the temperature of the display panel becomes significantly higher than the temperature during normal operation. Therefore, it is possible to suppress the occurrence of a state in which the display panel, which may have become unable to normally output an image corresponding to the input, continues to operate. That is, it is possible to suppress abnormal image output due to the temperature of the display panel becoming significantly higher than the temperature during normal operation.
　また、所定温度が、液晶１５が異方性を示す状態の温度と、当該液晶１５が等方性を示す状態の温度と、の間の相転移温度（Ｔｃ）未満であることで、表示パネル（例えば、表示パネルＰ）が相転移温度以上の温度になる前に、当該表示パネルが通常動作時の温度よりも上がっていることを検出できる。なお、相転移温度（Ｔｃ）未満の温度は、当該表示パネルの運用が想定されている温度帯（例えば、－４０度（℃）から９０度（℃））を超える温度であることが望ましい。 The predetermined temperature is less than the phase transition temperature (T c ) between the temperature at which the liquid crystal 15 exhibits anisotropy and the temperature at which the liquid crystal 15 exhibits isotropy. Before the temperature of the panel (for example, the display panel P) reaches the phase transition temperature or higher, it can be detected that the temperature of the display panel is higher than the temperature during normal operation. It should be noted that the temperature below the phase transition temperature (T c ) is preferably a temperature above the temperature range (for example, −40 degrees (° C.) to 90 degrees (° C.)) in which the operation of the display panel is assumed. .
　また、所定温度が、液晶１５が異方性を示す状態の温度と、当該液晶１５が等方性を示す状態の温度と、の間の相転移温度（Ｔｃ）以上であることで、当該相転移温度で生じる液晶１５の比誘電率の著しく大きな変化を利用して、より確実な表示パネル（例えば、表示パネルＰ）の温度に関する状況の検出を行える。従って、複数の当該第２電極の各々が位置する領域毎の温度が所定温度以上であるかの判定精度をより高められる。 The predetermined temperature is equal to or higher than the phase transition temperature (T c ) between the temperature at which the liquid crystal 15 exhibits anisotropy and the temperature at which the liquid crystal 15 exhibits isotropy. A significantly large change in the dielectric constant of the liquid crystal 15 that occurs at the phase transition temperature can be used to more reliably detect the temperature of the display panel (for example, the display panel P). Therefore, it is possible to further improve the accuracy of determining whether the temperature of each region where each of the plurality of second electrodes is located is equal to or higher than the predetermined temperature.
　また、第１電極（シールド電極２３）と第２電極（共通電極２２）とが液晶１５を挟んで対向することで、液晶１５の相転移温度で生じる液晶１５の比誘電率の著しく大きな変化を利用した表示パネル（例えば、表示パネルＰ）の温度状態の検出を行える。 In addition, since the first electrode (shield electrode 23) and the second electrode (common electrode 22) face each other with the liquid crystal 15 interposed therebetween, a significantly large change in the dielectric constant of the liquid crystal 15 that occurs at the phase transition temperature of the liquid crystal 15 can be suppressed. The temperature state of the used display panel (for example, display panel P) can be detected.
　また、第１電極（シールド電極２３）と第２電極（共通電極２２）とが２つの基板の一方（対向基板１２）を挟んで対向することで、当該一方の比誘電率を考慮した表示パネル（例えば、表示パネルＰ）の温度状態の検出を行える。 In addition, the first electrode (shield electrode 23) and the second electrode (common electrode 22) face each other with one of the two substrates (counter substrate 12) interposed therebetween, so that the display panel takes into account the dielectric constant of the one substrate. (For example, the temperature state of the display panel P) can be detected.
　また、第２電極（共通電極２２）は、画像表示時に、表示パネル（例えば、表示パネルＰ）が有する画素電極２１との間で液晶１５の配向を決定する電界を生じさせる。これによって、当該第２電極を、画像表示時と温度状態の検出時の両方で利用することができ、画像表示時と温度状態の検出時の各々に専用の電極を設ける場合に比してコンパクトで低コストな表示パネルを実現できる。 Also, the second electrode (common electrode 22) generates an electric field that determines the orientation of the liquid crystal 15 between the second electrode (common electrode 22) and the pixel electrode 21 of the display panel (for example, the display panel P) during image display. As a result, the second electrode can be used both when displaying an image and when detecting a temperature state. can realize a low-cost display panel.
　さらに、共通電極２２が表示領域ＡＡ内で複数に分割されていることで、ホットスポットＨＳによる熱が共通電極２２の電気抵抗値に与える影響を当該ホットスポットＨＳの位置に対応する共通電極２２に集中的に発生させることができる。従って、ホットスポットＨＳの発生に対応した表示パネルＰの動作制御をより確実に行える。 Further, since the common electrode 22 is divided into a plurality of areas within the display area AA, the influence of the heat generated by the hotspot HS on the electrical resistance of the common electrode 22 can be transferred to the common electrode 22 corresponding to the position of the hotspot HS. can be generated intensively. Therefore, the operation control of the display panel P corresponding to the occurrence of the hot spot HS can be performed more reliably.
　なお、表示パネルＰ（図４参照）及び表示パネルＰ２（図１３参照）のように、共通電極２２とシールド電極２３との間に対向基板１２が位置する構成では、表示パネルＰの温度状態の検出精度をより高めるために、対向基板１２のガラス厚を適切に決定することが望ましい。 Note that in a configuration in which the counter substrate 12 is positioned between the common electrode 22 and the shield electrode 23 as in the display panel P (see FIG. 4) and the display panel P2 (see FIG. 13), the temperature state of the display panel P In order to further improve detection accuracy, it is desirable to appropriately determine the glass thickness of the opposing substrate 12 .
　図１７は、１度（℃）の温度変化により生じる静電容量の変化の度合いに対してガラス厚がもたらす影響を示すグラフである。図１７では、１度（℃）の温度変化により生じる静電容量の変化の度合いを「１度辺りの検出容量差（ｆＦ／℃）」として示している。図１７に示すように、ガラス厚が増すほど、１度（℃）の温度変化により生じる静電容量の変化の度合いが小さくなる。従って、表示パネルＰ（図４参照）及び表示パネルＰ２（図１３参照）のように、共通電極２２とシールド電極２３との間に対向基板１２が位置する構成では、対向基板１２のガラス厚をより薄くすることで、温度変化をより確実に検出しやすくなる。従って、表示パネルＰ及び表示パネルＰ２では、対向基板１２の物理的強度が損なわれない範囲内でガラス厚を薄くすることが望ましい。具体的には、図１７の基準線ＧＬで示すように、１度辺りの検出容量差が１０．０（ｆＦ／℃）以上であれば、ＡＤＣ後データに基づいたホストコントローラ３２の温度状態の検出及びＨＵＤコントローラ３３の動作制御を十分に行える精度を得られる。対向基板１２の厚みが２００μｍ以下であれば、このような１０．０（ｆＦ／℃）以上の検出容量差が十分に生じる。従って、対向基板１２の厚みは、２００μｍ以下であることが望ましい。 FIG. 17 is a graph showing the effect of glass thickness on the degree of change in capacitance caused by a temperature change of 1 degree (°C). In FIG. 17, the degree of change in capacitance caused by a temperature change of 1 degree (° C.) is indicated as “detected capacitance difference per 1 degree (fF/° C.)”. As shown in FIG. 17, as the glass thickness increases, the degree of change in capacitance caused by a temperature change of 1 degree (° C.) decreases. Therefore, in a configuration in which the counter substrate 12 is positioned between the common electrode 22 and the shield electrode 23, such as the display panel P (see FIG. 4) and the display panel P2 (see FIG. 13), the glass thickness of the counter substrate 12 is Making it thinner makes it easier to detect temperature changes more reliably. Therefore, in the display panel P and the display panel P2, it is desirable to reduce the thickness of the glass within a range in which the physical strength of the opposing substrate 12 is not impaired. Specifically, as shown by the reference line GL in FIG. 17, if the detected capacitance difference per degree is 10.0 (fF/° C.) or more, the temperature state of the host controller 32 based on post-ADC data is It is possible to obtain sufficient accuracy for detection and operation control of the HUD controller 33 . If the thickness of the counter substrate 12 is 200 μm or less, such a detection capacitance difference of 10.0 (fF/° C.) or more is sufficiently generated. Therefore, it is desirable that the thickness of the opposing substrate 12 is 200 μm or less.
　ただし、ＡＤＣ部の分解能が高い程、対向基板１２の厚みに対する要件（より薄くすること）は緩和される。従って、対向基板１２の厚みは、ＡＤＣ部の分解能に応じたものであることが望ましい。 However, the higher the resolution of the ADC section, the more relaxed the requirements for the thickness of the opposing substrate 12 (to make it thinner). Therefore, it is desirable that the thickness of the counter substrate 12 corresponds to the resolution of the ADC section.
　また、上述の説明では、表示パネルＰにおいて閾値（例えば、値ＴＬ１、値ＢＬ又は値ＴＬ２）以上のＡＤＣ後データが生じた場合にＨＵＤコントローラ３３が表示パネルＰ全体の動作を停止させているが、温度状態の検出に対応した表示パネルＰの動作制御は表示パネルＰ全体の動作停止に限られるものでない。例えば、閾値（例えば、値ＴＬ１、値ＢＬ又は値ＴＬ２）以上のＡＤＣ後データを生じさせた静電容量が検出された共通電極２２の位置に対応する表示パネルＰの部分領域を基準として、ＨＵＤコントローラ３３が表示パネルＰの一部の画素の動作を停止させるようにしてもよい。具体的には、ＨＵＤコントローラ３３が、当該部分領域に含まれる画素又は当該部分領域と当該部分領域の周辺の一部の領域に含まれる画素の動作を停止させ、他の画素の動作による表示出力を継続させるようにしてもよい。さらに、ＨＵＤコントローラ３３が画素の動作を停止させた領域（停止領域）に対する光源５０からの光の照射を停止させることで、当該停止領域の温度の上昇をより確実に抑制することもできる。また、当該停止領域における画素の動作の停止後も、当該部分領域の温度状態検出を継続し、表示パネルＰが問題なく動作できる温度状態に復帰した場合、ＨＵＤコントローラ３３が当該停止領域に含まれる画素の動作を再開させるようにしてもよい。 In the above description, the HUD controller 33 stops the operation of the entire display panel P when post-ADC data equal to or greater than a threshold value (for example, the value TL1, the value BL, or the value TL2) is generated in the display panel P. , the operation control of the display panel P corresponding to the detection of the temperature state is not limited to stopping the operation of the display panel P as a whole. For example, the HUD is based on the partial region of the display panel P corresponding to the position of the common electrode 22 where the capacitance that caused post-ADC data equal to or greater than a threshold value (eg, value TL1, value BL, or value TL2) was detected. The controller 33 may stop the operation of some pixels of the display panel P. Specifically, the HUD controller 33 stops the operation of the pixels included in the partial area or the pixels included in the partial area and a partial area around the partial area, and the display output by the operation of the other pixels. may be continued. Furthermore, the HUD controller 33 stops the irradiation of the light from the light source 50 to the area (stop area) where the operation of the pixels is stopped, so that the temperature rise of the stop area can be suppressed more reliably. Further, even after the operation of the pixels in the stop area is stopped, the temperature state detection of the partial area is continued, and when the display panel P returns to a temperature state in which the display panel P can operate without problems, the HUD controller 33 is included in the stop area. The operation of the pixel may be resumed.
　また、本実施形態において述べた態様によりもたらされる他の作用効果について本明細書記載から明らかなもの、又は当業者において適宜想到し得るものについては、当然に本開示によりもたらされるものと解される。 In addition, other actions and effects brought about by the aspects described in the present embodiment that are obvious from the description of the present specification or that can be appropriately conceived by those skilled in the art are naturally understood to be brought about by the present disclosure. .
１０　液晶表示装置
１１　アレイ基板
１２　対向基板
１５　液晶
２２　共通電極
２３　シールド電極
３２　ホストコントローラ
３３　ＨＵＤコントローラ
１００　ＨＵＤ
Ｐ　表示パネル 10 liquid crystal display device 11 array substrate 12 counter substrate 15 liquid crystal 22 common electrode 23 shield electrode 32 host controller 33 HUD controller 100 HUD
P display panel

Claims (7)

  1. 　所定方向に対向する２つの基板の間に挟まれた液晶の配向を制御して画像を表示する表示領域を有する表示パネルと、
    　前記表示領域を覆う第１電極と、
    　前記表示領域内のそれぞれ異なる位置に設けられて前記第１電極と前記所定方向に対向する複数の第２電極と、
    　前記第１電極と前記複数の第２電極の各々との間の静電容量に基づいて、前記複数の第２電極の各々が位置する領域毎の温度が所定温度以上であるか判定する判定部と、を備え、
    　前記第１電極のシート抵抗は、１０４Ω／□以下である
    　液晶表示装置。     a display panel having a display area for displaying an image by controlling the alignment of liquid crystal sandwiched between two substrates facing each other in a predetermined direction;
    a first electrode covering the display area;
    a plurality of second electrodes provided at different positions in the display area and facing the first electrode in the predetermined direction;
    A determination unit that determines whether the temperature of each region where each of the plurality of second electrodes is located is equal to or higher than a predetermined temperature, based on the capacitance between the first electrode and each of the plurality of second electrodes. and
    The liquid crystal display device, wherein the first electrode has a sheet resistance of 10 4 Ω/□ or less.
  2. 　前記判定部が検出した温度が所定温度以上である場合に前記表示パネルの動作を停止させる動作制御部を備える、請求項１に記載の液晶表示装置。 The liquid crystal display device according to claim 1, further comprising an operation control section that stops the operation of the display panel when the temperature detected by the determination section is equal to or higher than a predetermined temperature.
  3. 　前記所定温度は、前記液晶が異方性を示す状態の温度と、前記液晶が等方性を示す状態の温度と、の間の相転移温度未満である、請求項２に記載の液晶表示装置。 3. The liquid crystal display device according to claim 2, wherein the predetermined temperature is less than a phase transition temperature between a temperature at which the liquid crystal exhibits anisotropy and a temperature at which the liquid crystal exhibits isotropy. .
  4. 　前記所定温度は、前記液晶が異方性を示す状態の温度と、前記液晶が等方性を示す状態の温度と、の間の相転移温度以上である、請求項２に記載の液晶表示装置。 3. The liquid crystal display device according to claim 2, wherein said predetermined temperature is equal to or higher than a phase transition temperature between a temperature at which said liquid crystal exhibits anisotropy and a temperature at which said liquid crystal exhibits isotropy. .
  5. 　前記第１電極と前記第２電極とは、前記液晶を挟んで対向する
    　請求項１から４のいずれか一項に記載の液晶表示装置。     5. The liquid crystal display device according to claim 1, wherein the first electrode and the second electrode face each other with the liquid crystal interposed therebetween.
  6. 　前記第１電極と前記第２電極とは、前記２つの基板の一方を挟んで対向する
    　請求項１から５のいずれか一項に記載の液晶表示装置。     The liquid crystal display device according to any one of claims 1 to 5, wherein the first electrode and the second electrode are opposed to each other with one of the two substrates interposed therebetween.
  7. 　前記第２電極は、前記表示パネルが有する画素電極との間で前記液晶の配向を決定する電界を生じさせる、請求項１から６のいずれか一項に記載の液晶表示装置。 The liquid crystal display device according to any one of claims 1 to 6, wherein the second electrode generates an electric field that determines the orientation of the liquid crystal between the pixel electrode of the display panel and the second electrode.
PCT/JP2022/001386 2021-03-12 2022-01-17 Liquid crystal display device WO2022190637A1 (en)

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JP2011170328A (en) * 2010-01-20 2011-09-01 Semiconductor Energy Lab Co Ltd Method for driving display device and liquid crystal display device
US20140139570A1 (en) * 2012-11-21 2014-05-22 Apple Inc. Dynamic Color Adjustment for Displays Using Local Temperature Measurements
JP2015200720A (en) * 2014-04-04 2015-11-12 株式会社ジャパンディスプレイ Display device, temperature information acquisition device, and temperature information acquisition method
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