JP2007304168A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device which can prevent degradation of image quality when an abnormality occurs on a red light source composing a hybrid type back-light. <P>SOLUTION: When an abnormality in lighting of LED 13 (red light source) is detected by an LED abnormality detecting circuit 18, a control circuit 8 makes the LED 13 switch off, and further, while adjusting liquid crystal output brightness in each color of red, blue, and green, a video processing circuit 4 compensates for the balance of liquid crystal brightness in each color in the direction of reinforcing red. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device including a hybrid-type backlight unit that illuminates the back surface of a liquid crystal display panel with substantially white light and red light.

The liquid crystal display device includes a backlight (back illumination means) that illuminates the liquid crystal display panel from the back surface thereof, and generally emits combined light of red, green, and blue wavelengths as the backlight. A fluorescent tube (cold cathode tube) is employed.
Here, backlights with fluorescent tubes tend to be slightly lacking in the intensity of light in the red wavelength band compared to white balance, which is considered appropriate based on the color sensitivity of the human eye, further improving color reproducibility. In order to achieve this, it is desirable to employ a backlight that emits light in which light in the red wavelength band is reinforced than the light from the fluorescent tube. On the other hand, conventionally, for the purpose of improving color reproducibility, an LED type backlight in which LEDs of a plurality of colors emitting light of each wavelength of red, green, and blue are arranged, as disclosed in Patent Document 1 is shown. In addition, a hybrid backlight or the like in which both a conventional fluorescent tube and a red LED that supplements red wavelength light are arranged may be employed.
Patent Document 2 discloses a backlight device that turns on a secondary light source (LED or fluorescent tube) when a main light source (fluorescent tube) that constitutes a backlight of a liquid crystal panel fails and does not light up. ing.
In Patent Document 3, the presence / absence of abnormality of each of the three color (R, G, B) LEDs constituting the backlight of the liquid crystal panel is detected, and an alarm is output when abnormality of any of the LEDs is detected. A backlight unit is shown.
Japanese Patent Laid-Open No. 2004-139876 JP 2002-131746 A JP-A-11-64845

By the way, the LED element basically has a long life, but in the hybrid backlight, a large number of red LED elements are arranged, so that defective products (those that cannot emit light stably for a long time) are included therein. Is likely to be included.
For this reason, in the hybrid type backlight, the probability of occurrence of an abnormality in a part of red LED elements is relatively high, and when an abnormality occurs (the red LED is not lit), the balance of the display color of that part is lost, and the color There is a problem that unevenness and unevenness of brightness occur (image quality deteriorates). In particular, in a hybrid backlight used for a large liquid crystal panel, a very large number of red LED elements are provided, and the probability that defective products are mixed therein increases, so the above problem becomes more prominent.
Accordingly, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal display device capable of preventing deterioration in image quality when an abnormality occurs in a red light source constituting a hybrid backlight. There is.

In order to achieve the above object, the present invention provides a first illumination means (typical example of a fluorescent tube) that illuminates the back surface of a liquid crystal display panel with substantially white light and a plurality of arranged red light sources (typically red LEDs). Hybrid type backlighting means having each of the second illumination means for illuminating according to example), and an output for adjusting the output luminance of the liquid crystal display panel for each of a plurality of colors including red according to the video content to be displayed on the liquid crystal display panel The present invention is applied to a liquid crystal display device including a brightness adjusting means, and includes the following components (1) and (2).
(1) A red light source abnormality detecting means for detecting a lighting abnormality of the red light source.
(2) When the lighting abnormality of the red light source is detected by the red light source abnormality detecting unit, the output luminance balance of each color of the liquid crystal display panel adjusted according to the video content is corrected by the output luminance adjusting unit. Output brightness correction means.
For example, the output luminance correction unit is configured to correct the output luminance of the liquid crystal display panel in the direction of increasing the red output luminance and decreasing the output luminance of the other colors.
With such a configuration, the shortage of red color caused by abnormal lighting (off) of the red light source can be compensated for by correcting the output luminance balance of each color in the liquid crystal display panel, and deterioration of image quality can be prevented.

In addition, the liquid crystal display device according to the present invention may further include the components shown in the following (3).
(4) A red light source extinguishing control unit that extinguishes the red light source including the one in which the abnormal lighting is detected when the red light source abnormality detecting unit detects the lighting abnormality of the red light source.
However, in this case, the output luminance correction means corrects the balance of the output luminance of each color of the liquid crystal display panel for the display area of the liquid crystal display panel corresponding to the red light source turned off by the red light source extinction control means. .
As a more specific example, it is conceivable that the red light source extinguishing control means turns off all the red light sources when the red light source abnormality detecting means detects an abnormal lighting of the red light source. .
As a result, the entire display area of the liquid crystal display panel has the same display conditions, and partial color unevenness and luminance unevenness can be prevented more reliably. Further, the red light source abnormality detecting means need only be able to detect that an abnormality has occurred in any one of the red light sources, even if the position of the red light source in which the lighting abnormality has occurred cannot be specified.
On the other hand, as another example, the red light source abnormality detecting means is configured to detect each of a plurality of sections in which the red light source abnormality can be blinked independently, and further, the red light source extinguishing control means, It can be considered that the red light source belonging to the section in which the lighting abnormality is detected by the red light source abnormality detecting means is turned off.
As a result, when a lighting abnormality occurs in some of the red light sources, partial color unevenness and brightness unevenness can be suppressed as much as possible while suppressing a decrease in the overall display brightness of the liquid crystal display panel.

  According to the present invention, even when a lighting abnormality (extinguishment) occurs in a red light source in a hybrid-type backlight unit (backlight), a shortage of red color caused by this occurs in the output luminance balance of each color in the liquid crystal display panel. It can be compensated by correction, and deterioration of image quality can be prevented.

Embodiments of the present invention will be described below with reference to the accompanying drawings for understanding of the present invention. In addition, the following embodiment is an example which actualized this invention, Comprising: It is not the thing of the character which limits the technical scope of this invention.
FIG. 1 is a block diagram showing a schematic configuration of a liquid crystal display device X according to an embodiment of the present invention, FIG. 2 is a flowchart showing a control procedure of backlight and liquid crystal output luminance in the liquid crystal display device X, and FIG. FIG. 6 is a graph of a γ table used for adjusting liquid crystal output luminance in the display device X.

First, the configuration of the liquid crystal display device X according to the embodiment of the present invention will be described using the block diagram shown in FIG. A liquid crystal display device X shown in FIG. 1 is a television receiver that displays an image based on a television broadcast signal received by an antenna or the like on a liquid crystal display panel 21 (hereinafter referred to as a liquid crystal panel).
Then, the liquid crystal display device X has a fluorescent tube 12 (an example of the first illumination means, represented as CFL in the figure) that illuminates the back surface of the liquid crystal panel 21 with substantially white light, and the back surface of the liquid crystal panel 21 as well. A hybrid backlight having each of an LED unit (not shown, one example of second illumination means) that illuminates with a plurality of red LEDs 13 arranged in a plurality is provided. Here, a television receiver is shown as an example of the configuration of the liquid crystal display device X. However, the application target of the present invention is not limited to this, and for example, a liquid crystal display device and a hybrid type back panel such as a liquid crystal display device of a computer. Any other liquid crystal display device may be used as long as it includes a light.
As shown in FIG. 1, the liquid crystal display device X includes a plurality of tuners 1a, 1b, 1c, an external input unit 2, a video switching circuit 3, a video processing circuit 4, a timer circuit 6, a remote controller 7, a control circuit 8, and a remote control interface. (I / F) circuit 9, liquid crystal panel 21, fluorescent tube 12 and LED 13 constituting a backlight, inverter circuit 14, LED drive circuit 15, color sensor 16, brightness sensor 17, LED abnormality detection circuit 18, audio switching circuit 10, an audio processing circuit 11, an amplifier 22, a speaker 23, and the like.

Each of the tuners 1a, 1b, and 1c receives a terrestrial broadcast signal, a BS satellite broadcast signal, and a CATV broadcast signal, and extracts a broadcast channel signal indicated by the control circuit 8 from the input broadcast signals. (Selection), and the video signal and the audio signal are extracted by detecting the extracted signal, and the video signal and the audio signal are transmitted to the video switching circuit 3 and the audio switching circuit 10, respectively.
The external input unit 2 receives an external input video signal and an external input audio signal such as a composite or separate video signal and audio signal from the outside, and inputs them to the video switching circuit 3 and the audio switching circuit. 10 is an interface for transmission to each.
The video switching circuit 3 inputs video signals from each of the tuners 1a, 1b, and 1c and a video signal from the external input unit 2, and selects any one of the video signals from the control circuit. 8 is selected and output in accordance with the instruction from FIG.

The video processing circuit 4 performs various signal processing on the video signal output from the video switching circuit 3. For example, separation of horizontal and vertical synchronization signals from the video signal, generation of a clock signal phase-synchronized with the synchronization signal, separation of luminance and color signals from the video signal, predetermined image quality improvement processing, etc. A signal is output to the liquid crystal panel 21.
Here, the video signal output from the video processing circuit 4 to the liquid crystal panel 21 is a signal representing the output luminance of each color of red, blue, and green. The video processing circuit 4 adjusts the level (output luminance level) of video signals of red, blue, and green in accordance with the video content displayed on the liquid crystal panel 21 (an example of output luminance adjusting means). Here, the video content is determined by the video gradation representing the density level of each pixel and each color. The video processing circuit 4 converts the video gradation to the level of the video signal according to a predetermined γ curve so that the display video on the liquid crystal panel 21 is visually recognized at a density corresponding to the video gradation (the video signal level is changed). Adjust). Hereinafter, the luminance represented by the video signal levels of red, blue, and green adjusted by the video processing circuit 4 is referred to as liquid crystal output luminance.

The control circuit 8 is an MPU 8a that is an arithmetic means, a ROM 8b (EPROM) that is a storage means in which a control program executed by the MPU 8a is stored in advance, and a setting that is read / written (referenced or written) in processing executed by the MPU 8a. An EEPROM 8c or the like for storing information is provided, and the entire liquid crystal display device X is controlled.
The timer circuit 6 measures time and time specified by the control circuit 8. The time measurement result of the timer circuit 6 is transmitted to the control circuit 8.
The remote control interface circuit 9 obtains operation input information for the remote control 7 by wireless transmission such as infrared transmission from the remote control 7 (remote operation device) for operation of the liquid crystal display device X, and the operation input information is controlled by the control. This is output to the circuit 8.
For example, when channel selection is performed, operation input information for the channel 1 selection key of the remote controller 7 is input to the control circuit 8 through the remote control interface circuit 9 and is controlled by the control circuit 8 according to the operation input information. The channel to be selected is designated for any one of the tuners 1a, 1b, and 1c, and the video switching circuit 3 is controlled so that the video of the channel is displayed on the liquid crystal panel 21.
Similarly, when volume adjustment is performed, an output volume adjustment command is sent from the control circuit 8 to the amplifier 22 in accordance with operation input information for a volume volume adjustment key (volume up key and down key) of the remote controller 7. In accordance with the command, the output volume for the speaker 23 is adjusted by the amplifier 22.

The audio switching circuit 10 receives an audio signal from each of the tuners 1a, 1b, and 1c and an audio signal from the external input unit 2, and controls any one of the audio signals as the control signal. According to an instruction from the circuit 8, the sound is output to the sound processing circuit 11.
The audio processing circuit 11 performs various signal processing on the audio signal output from the audio switching circuit 10 in accordance with instructions from the control circuit 8. For example, equalization processing, surround processing, or the like that matches the characteristics of the speaker 23 is performed.
The amplifier 22 performs a process of amplifying or attenuating the audio signal processed by the audio processing circuit 11 in accordance with an instruction from the control circuit 8 and outputs the amplified signal to the amplifier 23.
The liquid crystal panel 21 displays video based on the video signal output from the video processing circuit 4.
The brightness sensor 17 is a sensor that detects the brightness of the front side of the liquid crystal panel 21 (the brightness of the installation environment of the liquid crystal display device X), and the color sensor 16 is on the back side of the liquid crystal panel 21. This is a sensor that detects the color distribution of light (distribution of R, G, and B). These sensors are used for brightness (output) control of the fluorescent tube 12 and the LED 13 as described later.

The fluorescent tube 12 constituting the backlight (back illumination means) of the liquid crystal panel 21 emits substantially white light, which is a combined light of red, green, and blue wavelengths, and a plurality of fluorescent tubes are provided. They are arranged and arranged (an example of first illumination means). Similarly, the LED 13 that constitutes the backlight is a red LED that emits light having a red wavelength, and a plurality of LEDs 13 are arranged between the plurality of fluorescent tubes 12 (an example of a second illumination unit).
The fluorescent tube 12 is driven by the inverter circuit 14 (shown as an INV circuit in the figure), and the inverter circuit 14 adjusts the power supplied to the fluorescent tube 12 in accordance with a control command output from the control circuit 8. Specifically, a rectangular wave pulse signal is output from the control circuit 8 to the inverter circuit 14, and a pulsed drive voltage having a duty ratio corresponding to the duty ratio of the pulse signal is supplied to the fluorescent tube 12. . Then, by adjusting the duty ratio of the pulse signal output from the control circuit 8 to the inverter circuit 14, the brightness of the fluorescent tube 12 is adjusted by PWM (Pulse Width Modulation) dimming. As a result, the fluorescent tube 12 is turned on / off and the brightness is controlled.
On the other hand, the LED 13 (red LED) is driven by the LED drive circuit 15, and the LED drive circuit 15 adjusts the supply current to the LED 13 in accordance with the control command output from the control circuit 8, thereby using the current dimming method. The brightness of the LED 13 is adjusted. As a result, the LED 13 is turned on / off and the brightness is controlled.

  The LED abnormality detection circuit 18 is a circuit (an example of a red light source abnormality detection unit) that detects a lighting abnormality of the LED 13 (red light source) and transmits a detection result to the control circuit 8. The LED abnormality detection circuit 18 is, for example, a signal between the LED drive circuit 15 and the LED 13 (red LED element) in a state where the LED 13 is driven by the LED drive circuit 15 (a lighting signal is output). Whether or not the LED 13 is lit (normal or abnormal lighting) by detecting whether or not a signal higher than the reference voltage (or reference current) is generated in each signal line by a comparator connected to the line It is a circuit that detects whether or not. Here, the LED abnormality detection circuit 18 determines whether all of the plurality of LEDs 13 are normal by an AND circuit that generates a logical product signal of the output signals of each of the comparators (ON when normal, OFF when abnormal). It shall be detected whether more than one lighting abnormality has occurred.

Next, referring to the flowchart shown in FIG. 2, the control of the backlight realized by the MPU 8a of the control circuit 8 executing a predetermined control program, and the video processing circuit 4 according to the control command from the control circuit 8 A procedure for controlling the liquid crystal output luminance to be executed will be described. The process shown in FIG. 2 is performed when the liquid crystal display device X is activated (powered on) by a user's operation on the remote controller 7 or at a time preset by a timer activation setting or the like. It is assumed that it is started when automatically starts. Further, S1, S2,... Shown below represent identification codes of processing procedures (steps).
[Steps S1 to S4]
First, the control circuit 8 turns on the fluorescent tube 12 (CFL) by controlling the inverter circuit 14 (S1), and further turns on all the LEDs 13 by controlling the LED drive circuit 15 (S2).
Next, the control circuit 8 detects the brightness on the front side of the liquid crystal panel 21 and the color (color distribution) of the light on the back side of the liquid crystal panel 21 through the brightness sensor 17 and the color sensor 16 (S3).
Further, the control circuit 8 corrects the output level (light emission intensity) of the fluorescent tube 12 according to the brightness detected in step S3, and controls the inverter circuit 14 based on the corrected output level (S4). That is, the control circuit 8 controls the brightness (output) of the fluorescent tube 12 according to the detection level of the brightness sensor 17 that detects the brightness of the front side of the liquid crystal panel 21. Specifically, the brightness (output) of the fluorescent tube 12 is increased as the front side of the liquid crystal panel 21 is brighter. Accordingly, it is possible to prevent the output image of the liquid crystal panel 21 from being relatively dark or feeling too bright in relation to the surrounding brightness.

[Step S5]
Next, the control circuit 8 refers to the signal transmitted from the LED abnormality detection circuit 18 to determine whether any one of the LEDs 13 has a lighting abnormality (S5).
Here, if the control circuit 8 determines that an abnormality has occurred in the LED 13, the control circuit 8 shifts the process from step S9 to S11 for executing the operation in the LED abnormality mode. In other cases, the control circuit 8 shifts the process from step S6 to S8 in which the operation in the LED normal mode is executed. Hereinafter, processing procedures in each of the LED normal mode (S6 to S8) and the LED abnormal mode (S9 to S11) will be described.

・ LED normal mode [Step S6]
In the normal LED mode, the control circuit 8 adjusts the brightness (output) of the LED 13 according to the color of light detected in step S3 (the color distribution of light on the back side of the liquid crystal panel 21) (S6). Specifically, based on the RGB color distribution detected by the color sensor 16, the control circuit 8 controls the reinforcement of red light by the LED 13 so that the color balance approaches a predetermined target white balance. (Automatic control) is performed. That is, the control circuit 8 automatically controls the light quantity of the LED 13 in accordance with a control rule that brings the detection result of the color sensor 16 close to the target value.

[Steps S7 and S8]
Further, the control circuit 8 sets a γ table used for adjusting the liquid crystal output luminance for the video processing circuit 4 (S7).
The graphs indicated by solid lines in FIGS. 3A and 3B are graphs of the γ table used for adjusting the liquid crystal output luminance. FIG. 3A illustrates a γ table (RTγ [i]) relating to red liquid crystal output luminance, and FIG. 3B illustrates a γ table relating to green liquid crystal output luminance (GTγ [i]). The same applies to blue.
As shown by a solid line graph in FIG. 3, the γ table is a conversion table (data table) that defines a γ curve for converting the video gradation into the video output luminance. Here, the γ table differs for each brightness setting value (= i) set by the user. In step S7, the control circuit 8 selects one γ table for each color (R, G, B) and sets it in the video processing circuit 4 according to the brightness setting value preset by the user.
Further, the video processing circuit 4 adjusts the liquid crystal output luminance by converting the video gradation into the liquid crystal output luminance based on the γ table set in step S7 (S8). As a result, an image is displayed on the liquid crystal panel 21.
When the LED normal mode processing (S6 to S8) described above is completed, the control circuit 8 shifts the processing to step S3 described above. Thereby, the process from step S3 is repeated again.

・ LED abnormal mode
[Steps S9 to S11]
On the other hand, in the LED abnormality mode (when the abnormality of the LED 13 is detected by the LED abnormality detection circuit 18), first, the control circuit 8 controls all the LED 13 (lighting abnormality is detected by controlling the LED driving circuit 15). One example of a red light source including one is turned off (S9, one example of a red light source extinguishing control unit).
In addition, the control circuit 8 sets a γ table used for adjusting the liquid crystal output luminance for the video processing circuit 4, and further outputs the liquid crystal of each color (R, G, B) determined based on the γ table. A correction coefficient used for luminance correction is also set for the video processing circuit 4 (S10).
In step S10, the control circuit 8 selects one γ table for each color and sets it in the video processing circuit 4 according to the brightness setting value set in advance by the user, as in the processing in step S7. To do.
Further, in step S10, the control circuit 8 determines the liquid crystal output luminance (liquid crystal) of each color determined according to the γ table of each color of red, green and blue and the video content of each color (that is, according to the video gradation). A correction coefficient for correcting the output brightness of each color of the panel 21 in the direction of increasing the brightness for red and the direction of decreasing the brightness for green and blue is set in the video processing circuit 4.
In FIG. 3A, the red γ table (RTγ [i]) adopted when the brightness setting value = i is corrected based on the red correction coefficient set in step S10. The γ table (RTr ′ [i]) is illustrated by a broken line graph.
Further, in FIG. 3B, the green γ table (GTγ [i]) adopted when the brightness setting value = i is corrected based on the green correction coefficient set in step S10. The later γ table (GTr ′ [i]) is illustrated by a broken line graph.
As for the blue color, as in the case of the green color shown in FIG. 3B, the correction coefficient in the direction of decreasing the liquid crystal output luminance is set.
These correction coefficients are determined based on experiments or the like performed in advance for each brightness setting value, and are stored in advance in the EEPROM 8c or the like of the control circuit 8.

[Step S11]
Further, the video processing circuit 4 converts the video gradation into the liquid crystal output luminance (that is, adjusts based on the video content) based on the γ table set in step S10, and each color obtained by the conversion Is corrected based on the correction coefficient of each color set in step S10 (S11, an example of output luminance correction means). Accordingly, an image in which red is reinforced with respect to green and blue is displayed on the liquid crystal panel 21 as compared with the LED normal mode. Here, since all the LEDs 13 are turned off in step S9, the liquid crystal output luminance is corrected for all display areas (all pixels) of the liquid crystal panel 21 corresponding thereto.
As described above, the video processing circuit 4 adjusts the liquid crystal output luminance of each color of red, blue, and green based on the video content (the video gradation) (an example of output luminance adjusting means) and also displays the entire display area ( For the display area corresponding to all the LEDs 13 that have been turned off, the balance of the liquid crystal output brightness of each color is corrected in a direction that reinforces red (an example of output brightness correction means).
When the LED abnormality mode processing (S9 to S11) described above is completed, the control circuit 8 shifts the processing to step S3 described above. Thereby, the process from step S3 is repeated again.
As described above, in the liquid crystal display device X, even if the red LED 13 in the hybrid backlight is abnormally lit (extinguishes), the red shortage caused by this is reduced to the liquid crystal of each color in the liquid crystal panel 21. The balance of output luminance can be compensated by correction, and deterioration of image quality can be prevented.

The liquid crystal display device X shown above corrects the liquid crystal output brightness of red in the direction of increasing the liquid crystal output brightness of red when operating in the LED abnormal mode. It is conceivable that only correction for increasing the liquid crystal output brightness of red or only correction for increasing the liquid crystal output brightness of colors other than red is performed.
Further, the correction method of the red liquid crystal output luminance is not limited to the above-described method. For example, both the γ table before correction and the γ table after correction are stored in the storage unit in advance, and the LED normal mode and the LED are corrected. A configuration in which which γ table is used depending on which of the abnormal modes is used is an example of the embodiment of the present invention.

Further, in the above-described embodiment, an example is shown in which, when a lighting abnormality of the LED 13 occurs, all the LEDs 13 are turned off and the liquid crystal output luminance correction (color balance correction) is performed for all display areas of the liquid crystal panel 21. However, the following embodiments are also conceivable.
First, the LED drive circuit 15 is configured to be capable of blinking independently for each of the divided LEDs 13 or a set of LEDs 13. For example, it is configured to be able to blink for each LED 13 for one line in the horizontal direction or for each LED 13 one by one.
Further, the LED abnormality detection circuit 18 is configured to detect the presence or absence of lighting abnormality of the LED 13 belonging to each section for each section of the LED 13 that can be blinked independently by the LED drive circuit 15. For example, a lighting abnormality is detected by detecting a voltage or current state for each signal line to the LEDs 13 for one horizontal line or for each signal line to each LED 13.
When the lighting abnormality of the LED 13 is detected by such an LED abnormality detecting circuit 15, the control circuit 8 controls the LED driving circuit 15, so that the LEDs 13 (1 line) belonging to the category where the lighting abnormality is detected. Minute LEDs 13 or individual LEDs 13). At the same time, the control circuit 8 notifies the video processing circuit 4 of the region (pixel) corresponding to the category where the abnormality of the LED 13 is detected, so that the video processing circuit 4 is notified of the notified region (pixel). Only the liquid crystal output luminance correction (color balance correction) described above is performed.
In this case, since the brightness of the backlight is lowered in the area where the LED 13 is turned off, it is possible to correct the green and blue liquid crystal output brightness slightly higher and to further increase the red liquid crystal output brightness further. Conceivable.
Thereby, when a lighting abnormality occurs in some of the LEDs 13, partial color unevenness and luminance unevenness can be suppressed as much as possible while suppressing a decrease in the overall display brightness of the liquid crystal panel 21 as much as possible.

  The present invention is applicable to a liquid crystal display device.

1 is a block diagram illustrating a schematic configuration of a liquid crystal display device X according to an embodiment of the present invention. 4 is a flowchart showing a control procedure for backlight and liquid crystal output luminance in the liquid crystal display device X. FIG. 6 is a graph of a γ table used for adjusting the liquid crystal output luminance in the liquid crystal display device X.

Explanation of symbols

X ... Liquid crystal display devices 1a, 1b, 1c ... Tuner 2 ... External input unit 3 ... Video switching circuit 4 ... Video processing circuit 6 ... Timer circuit 7 ... Remote control 8 ... Control circuit 9 ... Remote control interface circuit 10 ... Audio switching circuit 11 ... Audio processing circuit 12 ... Fluorescent tube (almost white light source)
13 ... LED (red light source)
DESCRIPTION OF SYMBOLS 14 ... Inverter circuit 15 ... LED drive circuit 16 ... Color sensor 17 ... Brightness sensor 18 ... LED abnormality detection circuit 21 ... Liquid crystal panel S1, S2, ... Step (processing procedure)

Claims (5)

Hybrid type backlighting means each having first illumination means for illuminating the back surface of the liquid crystal display panel with a substantially white light source and second illumination means for illuminating with a plurality of arranged red light sources, and an image to be displayed on the liquid crystal display panel A liquid crystal display device comprising output luminance adjusting means for adjusting the output luminance of the liquid crystal display panel for each of a plurality of colors including red according to the contents,
A red light source abnormality detecting means for detecting a lighting abnormality of the red light source;
Output luminance that corrects the balance of the output luminance of each color of the liquid crystal display panel that is adjusted according to the video content by the output luminance adjusting means when the red light source abnormality detecting means detects abnormal lighting of the red light source Correction means;
A liquid crystal display device comprising:   The liquid crystal display device according to claim 1, wherein the output luminance correction unit corrects the output luminance of the liquid crystal display panel in a direction to increase the red output luminance and decreases the output luminance of other colors. A red light source extinguishing control means for extinguishing the red light source including one in which a lighting abnormality is detected when the red light source abnormality detecting means detects an abnormal lighting of the red light source,
The output luminance correction means corrects the balance of the output luminance of each color of the liquid crystal display panel for the display area of the liquid crystal display panel corresponding to the red light source turned off by the red light source turn-off control means. 3. A liquid crystal display device according to either 1 or 2.   4. The liquid crystal display device according to claim 3, wherein the red light source extinguishing control means turns off all the red light sources when the red light source abnormality detecting means detects that the red light source is abnormally lit. The red light source abnormality detection means detects the abnormality of the red light source for each of a plurality of sections that can blink independently,
4. The liquid crystal display device according to claim 3, wherein the red light source extinguishing control means turns off the red light source belonging to the section where the lighting abnormality is detected by the red light source abnormality detecting means.

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