JP2004348162A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display which enables a user to view high-quality images from the start of viewing by heating the liquid crystal display panel a predetermined time prior to the start time of broadcasting the program expected to be viewed. <P>SOLUTION: The liquid crystal display which displays images on the liquid crystal display panel 3 having a liquid crystal layer and electrodes to apply data voltages on the liquid crystal layer is equipped with a heating means 4, 5 which memorize the program viewing pattern (history) and heat the liquid crystal display panel 3 a predetermined time prior to the start time of broadcasting the program expected to be viewed based on the program viewing pattern. The time to heat the liquid crystal display panel 3 is determined based on the temperature of the use environment. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device that displays an image using a liquid crystal display panel.

  In recent years, lighter and thinner display devices such as personal computers and television receivers have been required to be lighter and thinner. In response to such demands, a liquid crystal layer and a liquid crystal layer have been used instead of a cathode ray tube (CRT). Flat panel displays such as a liquid crystal display (LCD) using a liquid crystal display panel having an electrode for applying a data voltage to a liquid crystal layer have been developed.

  An LCD applies a desired electric field to a liquid crystal layer having an anisotropic dielectric constant injected between two substrates, and controls the intensity of the electric field to control the amount of light transmitted through the substrates to achieve a desired level. This is a display device for obtaining an image signal. Such LCDs are typical of portable simple flat panel displays. Among them, TFT LCDs using thin film transistors (TFTs) as switching elements are mainly used.

  However, it is known that the temperature characteristic of the liquid crystal has extremely poor followability to an input signal at a low temperature. Recently, since LCDs are widely used not only as display devices for computers but also as display devices for television receivers, the need to realize moving images has been increasing. There is a drawback that image quality deterioration such as tailing occurs and the quality of moving images is significantly reduced.

  In order to improve such a problem of the response speed of the liquid crystal at the time of low temperature, for example, Japanese Utility Model Laid-Open No. 1-140520, JP-A-3-33720, and JP-A-10-228013 disclose a liquid crystal at a low temperature. It has been proposed to provide a heating element and a heater for compensating response characteristics, forcibly raise the temperature of the liquid crystal display panel, and quickly raise the temperature to the normal operating temperature of the liquid crystal.

Japanese Patent Application Laid-Open No. Hei 10-333124 discloses that when the detection signal from the temperature sensor is lower than the non-display temperature of the liquid crystal display element, the voltage applied to the incandescent bulb (light source) is increased to raise the temperature of the liquid crystal display element. Thus, there is disclosed a liquid crystal display element in which the responsiveness of the liquid crystal display element at low temperatures is reduced without providing a heater such as a heating wire.
Published Japanese Utility Model Application No. 1-140520 JP-A-3-33720 JP-A-10-228013 JP-A-10-333124

  However, in the above-described conventional technology, when the main power supply of the liquid crystal display device is turned on and an input image is displayed, the deterioration of image quality is suppressed by raising the temperature of the liquid crystal display panel. From this point until the normal operating temperature of the liquid crystal is reached, there is a problem that the viewer must view a display image with poor image quality.

  The present invention has been made in view of the above problems, and a liquid crystal display is provided from a predetermined time before a broadcast start time of a program to be viewed so that the temperature reaches a temperature at which a correct image can be displayed at the viewing start time. An object of the present invention is to provide a liquid crystal display device capable of presenting a high-quality display image from the beginning of viewing by applying heat to a panel.

  According to a first aspect of the present invention, there is provided a liquid crystal display device for displaying an image using a liquid crystal display panel, comprising: means for storing a program viewing history; and a broadcast start time of a program expected to be viewed based on the program viewing history. Heating means for applying heat to the liquid crystal display panel a predetermined time before is provided. Thus, it is possible to control the liquid crystal display panel to reach a predetermined temperature (a temperature at which a correct image can be displayed) at a broadcast start time of a program expected to be viewed, and to display a high-quality display image from the beginning of the viewing. It becomes possible to watch.

  A second invention of the present application is characterized in that the predetermined time is obtained according to a use environment temperature. Thus, it is possible to keep the driving of the heating unit for a minimum necessary time, and it is possible to suppress an increase in power consumption.

  A third invention of the present application is characterized in that the heating means is a backlight light source that irradiates the liquid crystal display panel. Thereby, it is possible to apply heat to the liquid crystal display panel without adding a new member such as a heater, and to stabilize the operation of the backlight light source itself at the beginning of viewing.

  The fourth invention of the present application is characterized in that only a part of the backlight light source is used as the heating unit. This makes it possible to reduce power consumption as compared to a case where all of the backlight light sources are driven.

  The fifth invention of the present application is characterized in that some of the backlight sources used as the heating means are backlight sources corresponding to a lower portion of the liquid crystal display panel. As a result, power consumption can be reduced, and the entire surface of the liquid crystal display panel can be uniformly and efficiently heated.

  A sixth invention of the present application is characterized in that an OSD display indicating that the heating means is being driven is performed on the liquid crystal display panel. Thus, the user can recognize on the screen that the device is performing the warm-up drive.

  According to a seventh aspect of the present invention, in a liquid crystal display device for displaying an image using a liquid crystal display panel, an enhancement conversion parameter for causing the liquid crystal display panel to respond to a transmittance determined by an input image signal after one vertical display period has elapsed. Storage means for storing an input image signal, an emphasis conversion process for compensating optical response characteristics of the liquid crystal display panel by performing an emphasis conversion process on the input image signal using the emphasis conversion parameter, and a means for storing a program viewing history. Based on the program viewing history, so that the liquid crystal display panel has a reference temperature in the environment where the emphasis conversion parameter is actually measured at the broadcast start time of the program expected to be viewed. A heating means for applying heat to the liquid crystal display panel a predetermined time before the broadcast start time is provided. This makes it possible for the liquid crystal display panel to reliably reach the transmittance (target gradation luminance) determined by the input image signal after the elapse of one vertical display period at the viewing start time, thereby realizing high-quality image display. Can be.

According to an eighth aspect of the present invention, in the storage device according to the first aspect, the storage unit may include a plurality of different reference temperature conditions.
A plurality of enhancement conversion parameters for causing the liquid crystal display panel to respond to a transmittance determined by an input image signal after a lapse of one vertical display period are stored, and the heating means determines a broadcast start time of a program expected to be viewed. In addition, heat is applied to the liquid crystal display panel so that the liquid crystal display panel has a reference temperature higher than the use environment temperature and the lowest reference temperature. As a result, the warm-up driving time before the viewing start time can be reduced, and an increase in power consumption can be suppressed.

  The ninth invention of the present application is characterized in that the storage means is a table memory storing an enhancement conversion parameter specified from an image signal in a current vertical display period and an image signal one vertical display period ago. This makes it possible to perform desired gradation display by reliably compensating the optical response characteristics of the liquid crystal display panel for a moving image having any gradation transition.

  Since the liquid crystal display device of the present invention is configured as described above, the liquid crystal display device is set to display the liquid crystal display device a predetermined time before the expected program broadcast time so as to reach a temperature at which a correct image can be displayed at the viewing start time. By applying heat to the panel, a high-quality display image can be viewed from the beginning of viewing.

  Hereinafter, an embodiment of the liquid crystal display device of the present invention will be described in detail with reference to FIGS. Here, FIG. 1 is a block diagram showing a schematic configuration of a main part in the liquid crystal display device of the present embodiment, FIG. 2 is a flowchart showing an operation at the time of an on-timer in the liquid crystal display device of the present embodiment, and FIG. FIG. 4 is an explanatory view showing time-temperature / response time characteristics in a liquid crystal display device. FIG. 4A shows a positional relationship between a backlight light source using a direct-type CCFT and (b) and (c) a side-illuminated CCFT and a liquid crystal display panel. FIG.

  In FIG. 1 showing the liquid crystal display device of the present embodiment, reference numeral 1 denotes a tuner for outputting an image signal of a specified channel from a television broadcast wave received from an antenna (not shown), and 2 denotes an image signal selected by the tuner 1. Is an electrode driving unit that drives the voltage application electrode of the liquid crystal display panel 3 based on the above.

  Reference numeral 4 denotes a direct-illumination type or side-illumination type backlight light source disposed on the back surface of the liquid crystal display panel 3, and reference numeral 5 denotes a light source drive unit for driving and controlling turning off / on of the backlight light source 4. In addition, as the backlight light source 4, various light sources such as an LED (light emitting diode) light source can be used in addition to a fluorescent lamp (CCFT).

  Reference numeral 6 denotes a remote control light receiving unit for receiving instruction input information such as a viewing reservation start time, an end time, and a viewing channel from a remote controller (not shown). Reference numeral 7 denotes a temperature sensor for detecting a device internal temperature (usage environment temperature). Controls the operation of the tuner 1, the electrode driving unit 2, the light source driving unit 5, and other circuit units (not shown) based on various instruction input information received by the remote control light receiving unit 6 and detection data by the temperature sensor 7. It is a microcomputer to perform.

  The start time, end time, and viewing channel of the viewing reservation can be easily set and input by the user using EPG (Electronic Program Guide) information multiplexed with the television broadcast signal and transmitted. . Preferably, the temperature sensor 7 is provided so as to detect the temperature of the liquid crystal display panel 3 itself as much as possible, and not only one temperature sensor but also a plurality of temperature sensors may be provided at different positions in the device.

  Next, the microcomputer processing at the time of the on-timer viewing reservation operation in the present embodiment will be described with reference to FIGS. First, it is determined whether or not the warm-up mode of the present invention is set at the time of reservation of the on-timer (step 1). If the warm-up mode is set, the time tn before the viewing reservation time (viewing start time) is reached. Is detected (step 2). Here, the time tn is a preset time such as “15 minutes” or “30 minutes”, and may be set to a fixed value at the time of shipment from the factory, or may be arbitrarily set by the user at the time of on-timer reservation or the like. It may be possible.

  When the time tn before the viewing start time comes, the temperature T1 in the device detected by the temperature sensor 7 at that time is acquired (step 3), and when the backlight light source 4 is turned on, the liquid crystal display panel 3 is turned on. Calculates the time t1 required for the temperature to reach the normal operation temperature T2 (for example, 60 ° C.) of the liquid crystal from the temperature T1 (step 4).

  Further, the time t1 and the time tn obtained in Step 4 are compared (Step 5). If the time t1 is longer than the time tn, the backlight light source 4 is immediately turned on (Step 7). If the time t1 is smaller than the time tn, it is detected whether or not the current time is a time obtained by subtracting the time t1 from the viewing start time (step 6). Then, the backlight light source 4 is turned on (step 7).

  As described above, the backlight light source 4 is turned on to drive heat to the liquid crystal display panel 3 before the scheduled viewing time arrives, so that the liquid crystal display panel 3 is normally operated at the viewing start time reserved by the user. The operating temperature can be set to T2. During this period, the data electrodes of the liquid crystal display panel 3 are controlled so as to apply a black signal voltage, so that nothing is displayed on the screen (black display state).

  Next, when the current time coincides with the viewing start time (step 8), power is also supplied to the tuner 1 and other circuit units to turn on the system (step 9). As a result, an image signal relating to the channel reserved for viewing selected by the tuner 1 is output to the electrode driving unit 2, and a desired image is displayed on the liquid crystal display panel 3.

  As described above, according to the liquid crystal display device of the present embodiment, even in a low-temperature use environment, a viewer can view a high-quality moving image without degradation in image quality due to response characteristics of the liquid crystal from the start of viewing. For example, when a viewing reservation is set for a program in the early morning of winter (repeated reservation every day, repeated reservation every week, etc.), only by setting and instructing the warm-up mode of the present invention, the program video reserved for viewing can be read from the beginning (from the beginning of viewing). It is possible to view with high image quality.

  In the above-described embodiment of the present invention, the case where the user sets the warming-up mode has been described. However, even without such user setting, the warming-up mode of the present invention can be set according to the ambient temperature. The driving may be automatically started. That is, step 1 in FIG. 2 is not essential, and there is no problem even if it always starts from step 2. Alternatively, the operation may be started from step 2 only when it is detected that the time is midnight and early morning (0:00 to 8:00) in winter (December to February), for example, using the calendar clock function.

  Further, in the above-described embodiment of the present invention, the backlight unit 4 having a heating effect has been described as a heating unit for applying heat to the liquid crystal display panel 3, but the invention is not limited thereto. The heat generated by the circuit power supply unit may be used, or the liquid crystal may be heated by using the display electrodes of the liquid crystal display panel 3 as heating elements. Needless to say, a heat generating member such as a heater may be separately provided to heat the liquid crystal display panel 3.

  However, when the backlight light source 4 is driven to be turned on before the viewing start time as in the above embodiment, not only can the liquid crystal response speed at the viewing start time be guaranteed, but also the backlight light source 4 is used. It is also possible to stabilize the operation of the CCFT itself at the viewing start time. Further, in general, when the tube wall temperature is about 50 to 70 ° C., a large light emission luminance can be obtained in the CCFT, so that the video can be viewed with sufficient screen luminance from the start of the viewing.

  Furthermore, in the above-described embodiment, in order to minimize the power consumption associated with the lighting drive of the backlight light source 4 before the viewing start time, the lighting drive of the backlight light source 4 is performed before the viewing start time tn. The required driving time t1 is obtained, and the lighting drive of the backlight light source 4 is performed immediately before the start of viewing for the required minimum time t1, but the present invention is not limited to this, and the lighting driving time of the backlight light source 4 before the viewing start time is not limited to this. May be a fixed time determined in advance, or may be arbitrarily set by the user.

  Further, in the above-described embodiment, all the CCFT / LEDs provided as the backlight light source 4 are driven to be lit (full-surface lit) before the time tn of the viewing start time, but in order to further reduce power consumption. Alternatively, at the time of warm-up driving before the viewing start time, the temperature of the liquid crystal display panel may be raised by driving only a part of the CCFT / LEDs to light up.

  Here, when all the CCFT / LEDs are driven to be lit, the upper part of the liquid crystal display panel is more likely to heat up than the lower part due to the relationship of airflow and the like, and thus, for example, as shown in FIG. As described above, only the CCFT corresponding to the lower part of the liquid crystal display panel where the temperature hardly rises needs to be driven. In FIG. 4, the CCFT driven to light up the liquid crystal display panel before the viewing start time is indicated by hatching. Further, the liquid crystal display panel is shown by a broken line.

  In this case, in the flowchart shown in FIG. 2, the driving of the backlight light source is performed such that only part of the backlight light source is lighted and driven in step 7 and all the backlight light sources are lighted and driven when the system is turned on in step 9. Control may be performed. As a result, compared to a case where all of the backlight light sources are driven, in addition to the reduction in power consumption, it is possible to efficiently raise the temperature of the entire liquid crystal display panel and to make the temperature distribution of the liquid crystal display panel uniform. it can.

  Further, in the ON operation (warm-up driving) of the backlight light source in step 7 in FIG. 2, the number / number of CCFTs / LEDs to be driven for lighting may be increased with time. Also in this case, in order to make the temperature distribution of the liquid crystal display panel uniform, it is sufficient to sequentially drive the CCFT / LEDs corresponding to the lower portion of the liquid crystal display panel.

  Further, in the above-described embodiment, while the warm-up driving of the liquid crystal display panel 3 is performed before the viewing start time, a black signal voltage is applied to the data electrodes of the liquid crystal display panel 3 so that the black signal is displayed on the entire screen. Although the display state is set, the device is operating in the warm-up mode by displaying, for example, characters or characters indicating the remaining time until the reserved viewing time by OSD (on-screen display) (the heating unit is being driven). ) May be recognized on the screen.

  Alternatively, while the warm-up driving of the liquid crystal display panel 3 is performed before the viewing start time, for example, specific pattern data that repeats a black level, a white level, a black level,. May be applied. In this case, the response characteristics of the liquid crystal can be improved by forcibly moving the liquid crystal molecules of the liquid crystal layer largely.

  Further, in the above-described embodiment of the present invention, the viewing start time is set to the on-timer viewing reservation time instructed and input by the user, but the program viewing pattern may be changed by using EPG (electronic program guide) information. (History) may be stored, and the warm-up driving of the present invention may be performed based on the program viewing pattern before the broadcast start time of the program expected to be viewed. As a result, even if the setting of the on-timer reservation is not made, it is possible to always watch the program video of the user's interest in high image quality from the beginning of viewing.

  Next, another embodiment of the liquid crystal display device of the present invention will be described in detail with reference to FIGS. 5 to 8. The same reference numerals are given to the same portions as those in the above-described embodiment, and the description will be omitted. Here, FIG. 5 is a block diagram illustrating a schematic configuration of a main part in the liquid crystal display device of the present embodiment, FIG. 6 is a schematic explanatory diagram illustrating an example of an OS table memory in the liquid crystal display device of the present embodiment, and FIG. And FIG. 8 is an explanatory diagram showing the relationship between the voltage applied to the liquid crystal and the response of the liquid crystal in the liquid crystal display device according to the embodiment.

  The liquid crystal display device of the present embodiment is provided with a predetermined input image of the current frame according to a combination of the input image signal of the previous frame and the input image signal of the current frame in order to improve the response speed of the liquid crystal. A liquid crystal driving method for supplying a driving voltage higher (overshoot) or lower (undershoot) to a liquid crystal display panel than a gray scale voltage for a signal (hereinafter, overshoot (OS) in the present specification) (Defined as driving).

  In FIG. 5, reference numerals 11a and 11b denote OS table memories (ROMs) storing applied voltage data (emphasis conversion parameters) corresponding to gradation transitions before and after one frame period of the input image signal in accordance with the internal temperature of the apparatus. , 12 are a frame memory (FM), 13 is an input image signal (Current Data) of the Mth frame to be displayed, and an input image signal (Previous Data) of the (M−1) th frame stored in the frame memory 12. Are read from one of the OS table memories (ROM) 11a and 11b, and the M-th frame image is displayed based on the enhancement conversion parameter. This is an emphasis conversion unit that determines a necessary emphasis conversion signal (write gradation data).

  Here, the microcomputer 18 selects one of the OS table memories (ROM) 11a and 11b in accordance with the temperature inside the device detected by the temperature sensor 7, and emphasizes the switching control signal for switching the emphasis conversion parameter. Output to the converter 13. The emphasis conversion parameters LEVEL 1 and LEVEL 2 stored in the OS table memories (ROM) 11a and 11b correspond to the actual measurement of the optical response characteristics of the liquid crystal display panel 3 under the environment of the reference temperatures T3 and T4 (T3 <T4), respectively. These values are obtained in advance from the values, and the respective degree of emphasis conversion has a relationship of LEVEL1> LEVEL2.

  For example, when the number of display signal levels, that is, the number of display data is 256 gradations of 8 bits, even if the OS table memory (ROM) has enhancement conversion parameters (measured values) for all 256 gradations. For example, as shown in FIG. 6, for example, as shown in FIG. 6, only the emphasis conversion parameters (measured values) for nine representative tones for every 32 gradations are stored, and the emphasis conversion signals for the other gradations are stored in the measured values. , The storage capacity of the OS table memory (ROM) can be reduced.

  In the liquid crystal display device of the present embodiment, as shown in FIG. 7, if the internal temperature T1 detected by the temperature sensor 7 is equal to or lower than the switching threshold temperature Th, the microcomputer 18 instructs the emphasis conversion unit 13 to send an OS table. An instruction is given to select and refer to the memory (ROM) 11a. Thus, the emphasis conversion unit 13 performs an emphasis conversion process on the input image signal using the emphasis conversion parameter LEVEL 1 stored in the OS table memory (ROM) 11a.

  If the in-apparatus temperature T1 detected by the temperature sensor 7 is higher than the switching threshold temperature Th, the microcomputer 18 instructs the emphasis conversion unit 13 to select and refer to the OS table memory (ROM) 11b. As a result, the emphasis conversion unit 13 performs an emphasis conversion process on the input image signal by using the emphasis conversion parameter LEVEL 2 stored in the OS table memory (ROM) 11b.

  As described above, by performing overshoot driving to compensate for the optical response characteristics of the liquid crystal display panel 3 according to the use environment temperature, as shown in FIG. 8, one frame period (for example, in the case of a 60 Hz progressive scan, After the elapse of 16.7 msec), the liquid crystal can reach the transmittance (target gradation luminance) determined by the input image signal, and the target halftone can be displayed in a short time (within one frame period).

  However, the emphasis conversion parameters LEVEL 1 and LEVEL 2 are measured values of applied voltage data at which the liquid crystal can respond to the transmittance determined by the input image signal after one frame period has elapsed at the reference temperatures T3 and T4, respectively. If the temperature T1 in the device is significantly different from the reference temperatures T3 and T4, the liquid crystal can be accurately shifted for one frame period regardless of which one of the OS table memories (ROM) 11a and 11b is used for the emphasis conversion. It is not possible to respond to the transmittance determined by the input image signal after the elapse, and a correct image cannot be displayed.

  Therefore, the liquid crystal display device of the present embodiment sets the liquid crystal display panel 3 so that the liquid crystal display panel 3 becomes one of the reference temperatures T3 and T4 in the environment where the emphasis conversion parameters LEVEL 1 and LEVEL 2 are actually measured at the viewing start time. By applying heat to the liquid crystal display panel 3 a predetermined time before the reservation start time, a high-quality display image is presented from the beginning of viewing.

  That is, when the temperature T1 in the device detected by the temperature sensor 7 before the time tn before the viewing start time is equal to or lower than the reference temperature T3 (for example, 10 ° C.), the liquid crystal display panel is turned on when the backlight light source 4 is turned on. A time t3 necessary for the temperature of the liquid crystal 3 to reach the reference temperature T3 from the temperature T1 is calculated, and when a time t3 has elapsed before the viewing start time, the backlight light source 4 is driven to be turned on to heat the liquid crystal display panel 3. I do.

  When the temperature T1 in the device detected by the temperature sensor 7 before the time tn before the viewing start time is higher than the reference temperature T3 and equal to or lower than the reference temperature 4 (for example, 30 ° C.), the backlight light source 4 is turned on. In this case, the time t4 required for the liquid crystal display panel 3 to reach the reference temperature T4 from the temperature T1 is calculated, and when the time t4 has elapsed before the viewing start time, the backlight light source 4 is driven to light up, and The display panel 3 is heated.

  As described above, before the scheduled viewing time arrives, the backlight light source 4 is turned on in advance and heat is applied to the liquid crystal display panel 3. Therefore, the liquid crystal display panel 3 is turned on at the scheduled viewing start time by the user. It can be either reference temperature T3, T4. Therefore, the liquid crystal display panel 3 can reliably reach the transmittance (target gradation luminance) determined by the input image signal after one vertical display period has elapsed from the beginning of viewing regardless of the use environment temperature, and high image quality can be achieved. Image display can be realized.

  In the above-described embodiment, OS table memories (ROM) 11a and 11b storing two types of enhancement conversion parameters LEVEL 1 and LEVEL 2 corresponding to each of the two-stage temperature ranges are provided. Although the ROM 11a and 11b are switched and referred to based on the detection data of the temperature in the apparatus to perform the overshoot drive (emphasis conversion processing) using one of the emphasis conversion parameters LEVEL 1 and LEVEL 2 has been described. Needless to say, an overshoot drive (emphasis conversion process) may be performed by switching the emphasis conversion parameters LEVEL 1 to LEVEL m of one or more arbitrary numbers M.

  Also in this case, the liquid crystal display panel 3 is heated so as to have a reference temperature Tm (1 ≦ m ≦ M) higher and lower than the internal temperature T1, thereby shortening the warm-up driving time before the viewing start time. And an increase in power consumption can be suppressed. Further, the liquid crystal can be made to respond to the transmittance determined by the input image signal exactly after one frame period has elapsed from the beginning of the viewing, and a high-quality image display without an afterimage can be realized.

  Here, in order to stabilize the internal temperature of the apparatus at any of the above-mentioned reference temperatures Tm even after the start of viewing, the cooling fan (not shown) is appropriately driven to radiate heat, or the cooling fan (not shown) is turned on. The temperature inside the apparatus (panel temperature) may be adjusted by stopping and keeping the heat, or by heating with a heating member (not shown) such as a separately provided heater.

  Note that, in the above-described embodiment, in order to reliably compensate for the optical response characteristics of the liquid crystal display panel and enable a correct image display for a moving image having any gradation transition, the current frame is displayed. OS table memories (ROM) 11a and 11b storing two-dimensional matrix of enhancement conversion parameters (applied voltage data) addressed from the image signal and the image signal of one frame before are provided. Has been described in which the image signal of the current frame is subjected to the emphasis conversion. However, a one-dimensional table memory storing the emphasis conversion parameter (applied voltage data) uniquely determined from the gradation level of the image signal of the current frame is described. May be used.

  Further, in the above embodiment, a plurality of enhancement conversion parameters corresponding to each temperature range are stored in the OS table memory (ROM) provided individually, but a single OS table memory (ROM) is used. It is stored in a different table area, and the table area to be referred to is adaptively switched according to the switching control signal from the microcomputer 18 to switch and select the enhancement conversion parameter to be supplied to the liquid crystal display panel 3. You may comprise so that a signal may be calculated | required.

  Further, as an enhancement conversion parameter, for example, a two-dimensional function f (pre, cur) for each device temperature is prepared using, for example, a gray scale before the transition and a gray scale after the transition as variables. However, a configuration may be adopted in which an enhancement conversion process for compensating the optical response characteristics of the liquid crystal display panel 3 is performed.

FIG. 1 is a block diagram illustrating a schematic configuration of a main part in an embodiment of a liquid crystal display device of the present invention. 6 is a flowchart illustrating an operation at the time of an on-timer in one embodiment of the liquid crystal display device of the present invention. FIG. 4 is an explanatory diagram showing time-temperature / response time characteristics in one embodiment of the liquid crystal display device of the present invention. It is explanatory drawing which shows the positional relationship of the backlight light source and liquid crystal display panel which used (a) direct type CCFT and (b) (c) side irradiation type CCFT. FIG. 11 is a block diagram illustrating a schematic configuration of a main part of another embodiment of the liquid crystal display device of the present invention. It is a schematic explanatory view showing an example of an OS table memory in other embodiments of a liquid crystal display of the present invention. FIG. 11 is an explanatory diagram showing a relationship between a temperature in the device and a reference table memory in another embodiment of the liquid crystal display device of the present invention. FIG. 11 is an explanatory diagram showing the relationship between the voltage applied to the liquid crystal and the response of the liquid crystal in another embodiment of the liquid crystal display device of the present invention.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Tuner 2 Electrode drive part 3 Liquid crystal display panel 4 Backlight light source 5 Light source drive part 6 Remote control light receiving part 7 Temperature sensor 8, 18 Microcomputer 11a, 11b OS table memory (ROM)
12 Frame memory (FM)
13 Emphasis converter

Claims (9)

In a liquid crystal display device that displays an image using a liquid crystal display panel,
Means for storing a program viewing history;
A liquid crystal display device comprising a heating means for applying heat to the liquid crystal display panel a predetermined time before a broadcast start time of a program expected to be viewed based on the program viewing history. The liquid crystal display device according to claim 1,
2. The liquid crystal display device according to claim 1, wherein the predetermined time is determined according to a use environment temperature. The liquid crystal display device according to claim 1, wherein
The liquid crystal display device, wherein the heating means is a backlight light source that irradiates the liquid crystal display panel. The liquid crystal display device according to claim 3,
A liquid crystal display device, wherein only a part of the backlight light source is used as the heating unit. The liquid crystal display device according to claim 4, wherein
A liquid crystal display device wherein a part of the backlight light source used as the heating means is a backlight light source corresponding to a lower portion of the liquid crystal display panel. The liquid crystal display device according to any one of claims 3 to 5,
A liquid crystal display device performing an OSD display on the liquid crystal display panel indicating that the heating means is being driven. In a liquid crystal display device that displays an image using a liquid crystal display panel,
Storage means for storing an enhancement conversion parameter for causing the liquid crystal display panel to respond to a transmittance determined by an input image signal after a lapse of one vertical display period;
An emphasis conversion unit that performs an emphasis conversion process on an input image signal by using the emphasis conversion parameter, thereby compensating an optical response characteristic of the liquid crystal display panel;
Means for storing a program viewing history;
On the basis of the program viewing history, the broadcast start of the program expected to be viewed such that the liquid crystal display panel becomes the reference temperature in the environment where the emphasis conversion parameter is actually measured at the broadcast start time of the program expected to be viewed. A liquid crystal display device comprising: heating means for applying heat to the liquid crystal display panel a predetermined time before a time. The liquid crystal display device according to claim 7,
The storage means stores a plurality of enhancement conversion parameters for causing the liquid crystal display panel to respond to a transmittance determined by an input image signal after one vertical display period has elapsed under a plurality of different reference temperature conditions,
The heating means applies heat to the liquid crystal display panel so that the liquid crystal display panel has a reference temperature higher than the use environment temperature and the lowest reference temperature at a broadcast start time of a program expected to be viewed. A liquid crystal display device characterized by the above-mentioned. The liquid crystal display device according to claim 7, wherein
The liquid crystal display device according to claim 1, wherein said storage means is a table memory storing an enhancement conversion parameter designated from an image signal of a current vertical display period and an image signal of one vertical display period before.

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