WO2013099165A1 - Dispositif d'affichage à cristaux liquides - Google Patents

Dispositif d'affichage à cristaux liquides Download PDF

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Publication number
WO2013099165A1
WO2013099165A1 PCT/JP2012/008139 JP2012008139W WO2013099165A1 WO 2013099165 A1 WO2013099165 A1 WO 2013099165A1 JP 2012008139 W JP2012008139 W JP 2012008139W WO 2013099165 A1 WO2013099165 A1 WO 2013099165A1
Authority
WO
WIPO (PCT)
Prior art keywords
liquid crystal
crystal display
temperature
display device
luminance
Prior art date
Application number
PCT/JP2012/008139
Other languages
English (en)
Japanese (ja)
Inventor
和彦 依田
北村　満
Original Assignee
シャープ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by シャープ株式会社 filed Critical シャープ株式会社
Publication of WO2013099165A1 publication Critical patent/WO2013099165A1/fr

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Classifications

    • 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
    • G09G3/3406—Control of illumination source
    • 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
    • G02F1/13306—Circuit arrangements or driving methods for the control of single liquid crystal cells
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0247—Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/04—Maintaining the quality of display appearance
    • G09G2320/041—Temperature compensation
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/0626—Adjustment of display parameters for control of overall brightness
    • G09G2320/064—Adjustment of display parameters for control of overall brightness by time modulation of the brightness of the illumination source
    • 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 invention relates to a liquid crystal display device provided with a light source such as a backlight.
  • phase transition temperature about 100 ° C.
  • the phase transition occurs, and the liquid crystal becomes an isotropic liquid (normal liquid state) and the display function is lost. End up.
  • a liquid crystal display device is provided with a light source such as a backlight using a light emitting diode or the like. Since such a light source generates heat together with light, it tends to increase the temperature of the liquid crystal display device.
  • a thermistor for detecting the temperature of the backlight module is provided, and when the resistance value is lower than the reference value, the emission luminance is lowered, the temperature increase rate is slowed, and the temperature is lowered.
  • a technique is known in which the duty ratio of the luminance control signal is calculated and the power supplied to the backlight is controlled every time it is determined that the ambient temperature has changed by 0.5 ° C. (For example, refer to Patent Document 2).
  • the present invention has been made in view of the above points, and an object of the present invention is to suppress the temperature rise of the liquid crystal display device even when the ambient temperature is high, and to prevent the display screen from flickering. is there.
  • the first invention is A liquid crystal display panel with a light source; A temperature sensor for detecting the temperature of the liquid crystal display panel or its surroundings; A luminance control unit for controlling the luminance of the light source according to the detection result by the temperature sensor; With The luminance control unit is configured to control the luminance of the light source at every preset time.
  • the brightness control unit controls the brightness of the light source and thus the amount of heat generation to be lowered. Therefore, display is performed as much as possible with the luminance according to the temperature of the liquid crystal display panel while avoiding the state in which the liquid crystal display panel cannot be displayed. Moreover, since changes in brightness occur only at regular intervals, that is, the state of the same brightness continues for at least a certain period of time, so even if the ambient temperature fluctuates or the temperature changes suddenly, etc. The screen brightness changes frequently and does not flicker.
  • the second invention is A liquid crystal display device according to a first invention,
  • the light source is a backlight using a light emitting diode.
  • the third invention is A liquid crystal display device according to any one of the first and second inventions,
  • the light source is configured to be driven by a pulse width modulated drive signal;
  • the luminance control unit is configured to control the luminance of the light source by controlling a duty ratio of the drive signal.
  • the brightness of the light source can be adjusted to easily control the heat generation amount and the temperature of the liquid crystal display panel.
  • the fourth invention is: A liquid crystal display device according to any one of the first to third inventions,
  • the luminance control unit is configured to control the duty ratio of the drive signal by fixed point arithmetic based on a detection result by the temperature sensor.
  • the present invention even when the ambient temperature is high, it is possible to suppress the temperature rise of the liquid crystal display device and to prevent the display screen from flickering.
  • 3 is a flowchart showing processing performed by a control unit 120.
  • the liquid crystal display device includes a liquid crystal display unit 110 and a control unit 120, and performs display according to an image signal output from the image generation device 130. It has become.
  • the liquid crystal display unit 110 includes a backlight 111, a liquid crystal display panel 112, and a touch panel 113.
  • the backlight 111 includes, for example, a light emitting diode (LED) and includes a drive circuit 111a that outputs a drive signal for the backlight 111.
  • the liquid crystal display panel 112 includes, for example, a thermistor 112a that is a temperature sensor attached to a substrate of a liquid crystal driver (not shown).
  • the touch panel 113 outputs a contact position detection signal corresponding to the position where the user's finger or the like touches.
  • the control unit 120 is configured by, for example, a microcomputer, and includes a CPU 121, a RAM 122, a ROM 123, a timer 124, an I / O circuit 125, and an A / D converter 126.
  • the timer 124 is for measuring a preset time, for example, the passage of time every 10 seconds.
  • the I / O circuit 125 receives the image signal output from the image generation device 130, outputs a display control signal to the liquid crystal display panel 112, and outputs a pulse width modulation (PWM) signal to the drive circuit 111a. It has become.
  • PWM pulse width modulation
  • the A / D converter 126 performs A / D conversion (analogue) on the temperature detection signal output from the thermistor 112a and the contact position detection signal output from the touch panel 113 in accordance with the temperature of the liquid crystal display panel 112 (or its surroundings). / Digital conversion).
  • the CPU 121 of the control unit 120 executes a program stored in the ROM 123 to perform processing according to the operation of the touch panel 113 and outputs to the drive circuit 111a based on the temperature detection signal output from the thermistor 112a.
  • the duty ratio of the PWM signal to be controlled is controlled as shown in FIG. That is, when the temperature of the liquid crystal display panel 112 is 70 ° C. or lower, the backlight 111 is driven by a PWM signal having a duty ratio of 100% (or designated by the user). When the temperature of the liquid crystal display panel 112 exceeds 70 ° C. and lower than 85 ° C., the backlight 111 is driven by a PWM signal having a smaller duty ratio as the temperature increases. Further, when the temperature of the liquid crystal display panel 112 reaches 85 ° C. or higher, the light emission of the backlight 111 is stopped.
  • the liquid crystal display apparatus includes an automobile heater or an engine.
  • the heat from the backlight 111 is generated and the heat generated by the backlight 111 is generated.
  • heat flows out by heat radiation from the casing of the liquid crystal display device.
  • the temperature of the liquid crystal display panel 112 is determined by the balance of heat transfer, and the temperature of the liquid crystal display panel 112 can be easily controlled by controlling the amount of heat generated by the backlight 111, which is a large heat source, that is, the light emission luminance. Can be.
  • control unit 120 In this specification, an example of a specific processing operation performed by the control unit 120 will be described with reference to FIG.
  • the duty ratio of the PWM signal for driving the backlight 111 is calculated based on the detection result of the thermistor 112a. Specifically, based on the value THM_ADC obtained by A / D converting the output signal of the thermistor 112a with the A / D converter 126, the following fixed point calculation is performed, and PWM corresponding to the obtained value is performed. The signal is generated by the I / O circuit 125 and amplified by the drive circuit 111a, so that the backlight 111 is dimmed.
  • Duty ratio ⁇ 2 (A ⁇ THM_ADC) >> 10 + B
  • a and B are constants set in advance by linear approximation based on actual measurement, and >> 10 indicates that a 10-bit right shift operation is performed.
  • the set value is used.
  • a value twice as large as the duty ratio is obtained.
  • the value is not limited to this, and the obtained value and the duty ratio of the PWM signal generated by the I / O circuit 125 are calculated. And should correspond.
  • the control unit 120 performs control so that the luminance of the backlight 111, and hence the amount of generated heat, is reduced. Therefore, while avoiding the non-displayable state or irreversible high temperature destruction of the liquid crystal display panel 112, the display is not simply stopped at a high temperature, but is displayed as much as possible with the luminance according to the temperature of the liquid crystal display panel 112. Is done. Therefore, the liquid crystal display device can be easily applied when the temperature tends to be relatively high, such as in-vehicle use, and it is required to operate in such a high temperature environment.
  • the thermistor 112a is attached to the substrate of the liquid crystal driver.
  • the present invention is not limited thereto, and may be provided in the vicinity of the liquid crystal display panel 112 or in the backlight 111, directly or It is only necessary to detect the temperature of the liquid crystal display panel 112 indirectly.
  • dimming processing may be performed by timer interrupt processing.
  • the measurement time of the timer 124 of 10 seconds is merely an example, and the temperature of the liquid crystal display panel 112 may be set so as to maintain proper display performance without divergence or convergence.
  • the present invention is not limited to this, and other light emitting elements, sidelights, or the like may be used.
  • the present invention is useful for a liquid crystal display device provided with a light source such as a backlight.

Abstract

Selon la présente invention, afin de supprimer une augmentation de la température d'un dispositif d'affichage à cristaux liquides sans provoquer un papillotement dans un écran d'affichage si la température ambiante est élevée, un dispositif d'affichage à cristaux liquides est pourvu des éléments suivants : un panneau d'affichage à cristaux liquides (112) ayant une source de lumière (111) ; un capteur de température (112a) pour détecter la température du panneau d'affichage à cristaux liquides (112) ou la température ambiante ; une unité de commande de luminance (120) pour commander la luminance de la source de lumière (111) en fonction des résultats de détection du capteur de température (112). L'unité de commande de luminance (120) commande la luminance de la source de lumière (111) pour des passages de temps qui sont établis au préalable.
PCT/JP2012/008139 2011-12-26 2012-12-19 Dispositif d'affichage à cristaux liquides WO2013099165A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2011283516 2011-12-26
JP2011-283516 2011-12-26

Publications (1)

Publication Number Publication Date
WO2013099165A1 true WO2013099165A1 (fr) 2013-07-04

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104167169A (zh) * 2014-06-25 2014-11-26 程泓竣 一种led广告牌
FR3023510A1 (fr) * 2014-07-11 2016-01-15 Peugeot Citroen Automobiles Sa Vitrage de pavillon pour vehicule automobile comportant un film actif et des moyens de protection pour prolonger sa duree de vie
US10935824B2 (en) 2018-04-26 2021-03-02 Sharp Kabushiki Kaisha Liquid crystal display device having a temperature sensor
WO2023112919A1 (fr) * 2021-12-14 2023-06-22 矢崎総業株式会社 Dispositif d'affichage tête haute

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006171693A (ja) * 2004-11-19 2006-06-29 Sony Corp バックライト装置、バックライト駆動方法及び液晶表示装置
JP2010230860A (ja) * 2009-03-26 2010-10-14 Victor Co Of Japan Ltd 映像表示装置およびその光源制御方法
JP2010278366A (ja) * 2009-05-29 2010-12-09 Hitachi Ltd 照明装置及び液晶表示装置
WO2011001725A1 (fr) * 2009-07-03 2011-01-06 シャープ株式会社 Dispositif d'affichage à cristaux liquides et procédé de commande de source lumineuse

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006171693A (ja) * 2004-11-19 2006-06-29 Sony Corp バックライト装置、バックライト駆動方法及び液晶表示装置
JP2010230860A (ja) * 2009-03-26 2010-10-14 Victor Co Of Japan Ltd 映像表示装置およびその光源制御方法
JP2010278366A (ja) * 2009-05-29 2010-12-09 Hitachi Ltd 照明装置及び液晶表示装置
WO2011001725A1 (fr) * 2009-07-03 2011-01-06 シャープ株式会社 Dispositif d'affichage à cristaux liquides et procédé de commande de source lumineuse

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104167169A (zh) * 2014-06-25 2014-11-26 程泓竣 一种led广告牌
FR3023510A1 (fr) * 2014-07-11 2016-01-15 Peugeot Citroen Automobiles Sa Vitrage de pavillon pour vehicule automobile comportant un film actif et des moyens de protection pour prolonger sa duree de vie
US10935824B2 (en) 2018-04-26 2021-03-02 Sharp Kabushiki Kaisha Liquid crystal display device having a temperature sensor
WO2023112919A1 (fr) * 2021-12-14 2023-06-22 矢崎総業株式会社 Dispositif d'affichage tête haute
JP7421536B2 (ja) 2021-12-14 2024-01-24 矢崎総業株式会社 ヘッドアップディスプレイ装置

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