JP2001147673A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device that has made the largeness of a visual angle to be chageable, if necessary, only by signal processing and has made possible to secretly hide the display contents or optimize the visible direction, etc., without using the means such as a special liquid crystal cell for visual angle control, optical lens seat control, and optical characteristic variation of a back-light. SOLUTION: This liquid crystal display device comprises a signal control means for processing an input video signal in contrast, brightness, or the like individually for RGB, and a visual angle interlocking control means which has γ-conversion circuits, individually for RGB, for converting processed signal data into such impression voltages as provide a TV characteristic of a liquid crystal panel with a desired visual characteristic and controls to change over the plural γ-data according to prescribed pixel patterns to obtain the desired visual angle characteristic. Moreover, the visual angle interlocking control means performs the control to the signal control means and the γ-conversion circuits by interlocking adaptive control so as to effectively control the visual angle according to the feature information obtained from a video feature detection means for extracting features of the input video signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving circuit and a backlight device of a liquid crystal display device of a TN liquid crystal (twisted nematic liquid crystal), and a signal processing of a video signal inputted to the liquid crystal display device. The present invention relates to a control circuit of a liquid crystal display system that can appropriately control a viewing angle according to a use state and a viewing direction of a liquid crystal display device.

[0002]

2. Description of the Related Art In a TN liquid crystal system, which is widely used in liquid crystal TVs, light passing through a liquid crystal layer has various birefringences depending on its direction and angle due to the refractive index anisotropy and torsional alignment of the liquid crystal. The effect shows complicated viewing angle dependence, for example, generally, the entire screen becomes whitish at an upward viewing angle, the entire screen becomes dark at a downward viewing angle, and the brightness is inverted at a low luminance portion of the image. This phenomenon occurs.

With respect to such viewing angle characteristics, many techniques for widening the viewing angle with respect to luminance, hue, contrast characteristics, gradation characteristics, and the like by various methods have been developed. As such a technique, most of the techniques are very much improved with respect to the liquid crystal panel itself and those using an optical member, but the TFT process and the liquid crystal panel process are not complicated, and the yield and the cost are increased. As a method that does not cause the problem, a technique for widening the viewing angle only by signal processing of an external circuit is disclosed. This utilizes a viewing angle dependency of a transmittance characteristic (hereinafter referred to as a VT characteristic) with respect to an applied voltage of a liquid crystal cell, and prepares a plurality of gradation voltage conversion characteristics (hereinafter referred to as a γ characteristic) for an input signal. In this technique, a plurality of characteristics are visually combined to improve the viewing angle characteristics by driving the liquid crystal while performing the switching control at predetermined intervals.
No. 44, "Liquid crystal display device", and JP-A-9-90910, "Driving method of liquid crystal display device and liquid crystal display device". FIG. 11 shows an example of such a conventional liquid crystal display device having a wide viewing angle by external signal processing. In FIG. 11, RG
Γ conversion circuits γ1 and γ2 having a plurality of γ characteristics different from each other when a B image signal is input, and means for controlling switching of the γ characteristics for every n frames (n is a natural number) of the image signal. The liquid crystal drive is performed in accordance with the output. As a switching pattern of the γ characteristic, as shown in FIG. 12, the corresponding pixels of the n frames continuously and alternately in the pixel unit correspond to the same γ characteristic. It is configured to apply display signal voltages that are display voltages and have different polarities from each other. Here, the two γ-characteristics are optimized so that different viewing angles become the optimum visual field, for example, γ1 is optimized for an upper visual field of 10 °, γ2 is optimized for a lower visual field of 10 °, the γ-characteristic is fixed, and modulated by the switching pattern. Up and down 10
The operation is performed so as to widen the optimum gradation characteristics by about °.

On the other hand, as an attempt to make effective use of the viewing angle dependency, the purpose of concealing the display as protection of privacy in a notebook personal computer and optimizing the viewing direction when a wide viewing angle is not required are considered. For such purposes, proposals have been made for application to narrowing, returning, or moving the viewing angle. Other techniques for optimizing the control of narrowing or widening the viewing angle (expanding here does not mean widening as in Conventional Example 1 but expanding in the sense of returning the narrowed one) Also, a liquid crystal cell for controlling the amount of backlight in addition to the liquid crystal cell for displaying an image is provided, and various proposals have been made such as those that control this liquid crystal cell and those in which the light guide plate of the backlight is devised. As a technique for controlling the viewing angle characteristic only by the signal processing of the external circuit as in the conventional example 1, for example, there is a technique disclosed in Japanese Patent Application Laid-Open No. Hei 10-319373 “Liquid crystal display device and liquid crystal display system”. . FIG. 14 shows an example of such a conventional viewing angle control liquid crystal display system using external signal processing. This is because a TN liquid crystal panel that has been optimized for the rubbing direction and the deflection plate twist angle has a gradation signal voltage generation circuit for generating a plurality of gradation reference voltages and a desired viewing angle characteristic setting. A set value switching circuit for switching the set value is provided, and the optimum gradation reference voltage is applied, or the display data switching circuit converts the display data by simple gain control by bit processing so as to obtain the optimum reference voltage ( The angle of view is changed by the method of (correction).

As described above, in the prior art, as a technique for controlling the viewing angle characteristics only by signal processing of an external circuit, a plurality of fixed γ conversion characteristics are modulated for the purpose of widening the viewing angle. Although the method is shown, regarding the wide and narrow control of the viewing angle, as a method, using a liquid crystal panel that has been subjected to alignment processing, switching is performed so as to optimize the gradation signal voltage so as to achieve the set viewing angle characteristics. It has been disclosed.

[0006]

However, in the first conventional example, the purpose is to increase the viewing angle, so that the viewing angle is increased in a narrow viewing angle direction (for example, in the vertical direction). Γ of several different characteristics set
The characteristics themselves are fixedly used, and do not include the concept of controlling a plurality of γ characteristics themselves. In addition, optimization and adaptive control of the input video signal to the video state, or RGB
No specific gamma characteristic or control is specified.

In the second conventional example, the purpose is to control the widening and narrowing of the viewing angle. However, the γ characteristic itself is fixed for each desired viewing angle setting. Absent. Also, there is no description about the optimization or adaptive control of the input video signal to the video state, or the γ characteristics and control of each RGB. Further, neither of the conventional examples mentions the backlight.

Therefore, even in the prior art example 1, even when applied for the purpose of controlling or optimizing the viewing angle, a plurality of γ characteristics for widening the viewing angle characteristic are provided in, for example, a high luminance region as shown in FIG. In the case where the signals almost overlap each other and a signal almost concentrated in the high luminance area is input as the input video signal, there is almost no effect of widening the viewing angle, and conversely, the signal concentrates in the low luminance area. When such a signal is input, the difference in γ becomes large, so that it may be a cause of flicker or the like depending on the switching pattern due to a trade-off with the viewing angle improvement effect.

Generally, in the case of an input signal such as a personal computer screen or a car navigation screen,
The dynamic range of the input signal is large, and the signal component is often biased to relatively high or low luminance.
Conversely, when the video signal such as V is concentrated in the halftone,
Depending on the video scene, there are various types, such as concentration on high luminance and concentration on low luminance. In the case of the basic concept of controlling the viewing angle by optimizing the γ characteristic by using the difference in the VT characteristic depending on the viewing angle as in Conventional Example 1, the viewing angle control is performed by performing control according to an input signal. It is conceivable that image quality deterioration such as a decrease in luminance and contrast feeling due to the implementation can be suppressed, and the viewing angle control effect itself can be effectively applied.

[0010] In terms of system, in the conventional examples 1 and 2, 2
A car navigation image is displayed on the driver's seat side for the purpose of safety or the like in an in-vehicle TV or the like of a screen display system.
Viewing angle control such as displaying the V-image on the passenger seat side cannot be performed, and in the case of such a combination of signal sources, good viewing-angle control is difficult because the characteristics on the image are greatly different as described above. Becomes

Further, in the method of the prior art 2, it is impossible to widen the viewing angle more than usual, and control cannot be performed according to the state of the video signal as in the case of the conventional example 1.
In the case of an image in which the input signal is relatively concentrated in a halftone region, such as a general case of a TV signal, originally, the setting of the γ characteristic should be performed effectively because a stable portion having a gentle slope can be used. However, such control is impossible in the configuration of the conventional example 2.

Further, the ideal γ characteristic is determined by the characteristics of the color filter and the backlight of the liquid crystal display device from the viewpoint of RGB.
Since the γ characteristics do not match at all gradations among the signals and have color shift characteristics, in order to control the viewing angle while suppressing the occurrence of hue change or the like, the γ characteristics of RGB must be individually and further, It is necessary to set an optimum value even according to the gradation.

On the other hand, as is well known, in the case of the transmission type liquid crystal display system, the amount of light of the backlight is a large factor for the luminance characteristics, and thus has a considerable influence on the luminance and contrast of the displayed image. No consideration is given to this point.

The present invention has been made in view of the above-described problem in a technique for controlling a viewing angle characteristic by only signal processing of an external circuit, and has been made in view of the above-described problems. The control to obtain the angular characteristics can be performed by applying a more optimal applied voltage to the liquid crystal panel according to the specified desired viewing angle characteristics and the state of the input video signal, and the viewing angle control can be more effectively performed. In such a manner, the video signal processing and the γ characteristic and the switching pattern of the γ characteristic are linked and controlled adaptively, and the backlight is also linked and controlled.
It is an object to realize more optimal viewing angle control.

[0015]

In order to solve such a problem, a liquid crystal display device according to the present invention comprises: a signal control means for independently performing contrast, brightness processing, and the like on an input video signal; A RGB conversion circuit for converting video signal data into an applied voltage that provides a desired viewing angle characteristic from the VT characteristic of the liquid crystal panel is provided independently of RGB, and a plurality of γs individually set for RGB so that the desired viewing angle characteristic is obtained. There is a viewing angle interlocking control means for switching and controlling data in a predetermined pixel pattern. As a result, the plurality of gray scale voltages of the γ characteristic are input to each pixel in the TN type liquid crystal panel which has been subjected to the alignment control processing so that the viewing angle dependency in a predetermined direction is increased, and the perceptual characteristic is synthesized. In this case, the viewing angle interlocking control unit effectively controls the viewing angle by using the video feature information obtained from the video feature detection unit that extracts the features of the input video signal. A system configuration that performs adaptive control on the signal control means and the control of the γ conversion circuit in an interlocking manner, and also performs adaptive control on the backlight control means to perform backlight control. It is what it was.

Thus, in a system in which the viewing angle characteristic is controlled by signal processing of an external circuit, the viewing angle can be reduced more effectively in accordance with the state of the input video signal while suppressing image quality deterioration such as luminance, contrast, and hue change. A system for performing desired viewing angle control such as narrowing, widening, moving, or optimizing angular characteristics, or masking display in one direction, can be easily realized with a relatively simple circuit configuration.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claims 1 and 3 of the present invention relates to a drive circuit of an active matrix drive type liquid crystal display element and a liquid crystal display control device in a backlight system. RGB independent gamma conversion which can set signal control means for performing video signal processing and gamma conversion processing for inputting the signal processing data into an applied voltage to a liquid crystal application voltage with a plurality of different characteristics independently of RGB. Means and the RGB independent gamma conversion means so as to have a desired viewing angle characteristic.
View angle interlocking control means for controlling each gamma data setting and its switching pattern, and image feature detecting means for extracting characteristics of an input video signal and outputting image characteristic information to the viewing angle interlocking control means. The liquid crystal display device is characterized in that the control for achieving the set desired viewing angle characteristic is more optimal according to the specified desired viewing angle characteristic and the state of the input video signal. In order to control the viewing angle more effectively by applying an appropriate applied voltage to the liquid crystal panel, the video signal processing and the γ characteristic and the switching pattern of the γ characteristic are controlled in conjunction with each other in an adaptive manner. This has the effect of realizing viewing angle control.

The invention according to claims 2, 3 and 8 of the present invention relates to a drive circuit of an active matrix drive type liquid crystal display element and a liquid crystal display control device in a backlight system, wherein a video signal is applied to an input video signal. Signal control means for performing processing; and RGB independent gamma conversion means capable of setting gamma conversion processing for inputting the signal processing data into a liquid crystal application voltage with respect to an input value with a plurality of different characteristics for each of RGB. To the RGB independent gamma conversion means so as to have a desired viewing angle characteristic,
A viewing angle interlocking control unit that controls each gamma data setting and its switching pattern; an image feature detecting unit that extracts a feature of an input video signal and outputs image feature information to the viewing angle interlocking control unit; Backlight control means for controlling the backlight brightness of the liquid crystal panel by the interlocking control means, wherein the liquid crystal display device is characterized in that the control to achieve a desired viewing angle characteristic set, According to the specified desired viewing angle characteristics and the state of the input video signal, the video signal processing and γ are adaptively performed so that a more optimal applied voltage is applied to the liquid crystal panel and the viewing angle control can be performed more effectively. The function of controlling the characteristics and the switching pattern of the γ characteristics in conjunction with each other, and also controlling the backlight in conjunction with each other to achieve optimal viewing angle control with reduced image quality degradation. Having.

According to a fourth and fifth aspects of the present invention, the signal control means adjusts the contrast of the video signal (adjustment of the amplitude of the video signal) and the brightness (DC level). The characteristic detecting means obtains the maximum value and the minimum value of the luminance of the video signal for each screen, and the widest dynamic range of the gamma characteristic according to the luminance range of the input signal in one screen and a desired viewing angle characteristic. 4. A liquid crystal display device according to claim 1, wherein contrast and brightness are controlled so as to be able to be obtained or to control the viewing angle most efficiently. From the relationship between the viewing angle control value, which determines the angle characteristics, and the variable range of the brightness of the input video signal, the viewing angle control can be performed most efficiently and the optimum brightness can be obtained. Performs contrast control and γ characteristic setting has the effect of realizing a small viewing angle control image quality deterioration such as contrast deterioration by controlling the viewing angle.

According to the sixth and eleventh aspects of the present invention, the switching pattern of a plurality of gamma characteristics and each gamma data to be performed on the RGB independent gamma conversion means in the view angle interlocking control means are used for one screen. From among the symmetrically or asymmetrically alternating patterns for each pixel in the horizontal direction or the vertical direction, perform an optimal selection as appropriate according to the video feature information and the viewing angle setting obtained from the video feature detection means,
6. The liquid crystal display device according to claim 1, wherein control is performed so as to optimize gamma data, wherein the pixel size of the liquid crystal panel, the aspect ratio of the display screen, or the liquid crystal panel. Considering the characteristics, etc., by selecting the γ switching pattern according to the γ characteristic setting value and the state of the video signal and the signal source so as to obtain the desired viewing angle setting, image quality deterioration with reduced luminance and flicker is suppressed It has the effect of realizing the viewing angle control with less.

According to a seventh and twelfth aspect of the present invention, the switching pattern of a plurality of gamma characteristics and each gamma data to be performed on the RGB independent gamma conversion means in the view angle interlocking control means are provided in the field direction. On the other hand, from the symmetrical or asymmetrical alternating pattern, the video feature information obtained from the video feature detection means and the viewing angle setting are appropriately selected as appropriate, and the combined control is performed so that the gamma data is optimized. 6. The liquid crystal display device according to claim 1, wherein a gamma characteristic set value and a state of a video signal in a time axis direction, a signal source, or a scan of the video signal are set so that a desired viewing angle is set. By selecting a gamma switching pattern in the field direction according to the line format and scanning line conversion processing, image quality degradation with reduced luminance and flicker It has the effect of realizing the viewing angle control with less.

According to a ninth and tenth aspect of the present invention, in the liquid crystal display device according to the first to eighth aspects, the image feature detecting means, the signal control means, the RGB independent gamma converting means, and the visual field are provided. The angle interlocking control means can be individually controlled for each image display area. Even when a plurality of screens are simultaneously displayed in one screen, the viewing angle characteristic is set for each display screen. A liquid crystal display device characterized in that it can be individually controlled. In a vehicle-mounted TV with a two-screen display function, the TV display and the car navigation display are optimized in different viewing angle directions. In this way, the viewing angle direction can be controlled independently for each display screen.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram of a liquid crystal display device according to Embodiment 1 of the present invention. In FIG. 1, the present liquid crystal display device performs RGB processing of contrast and brightness on an input video signal. A signal control means 1 capable of processing with independent settings and an RGB independent gamma conversion circuit 2 (RGB independent gamma conversion means) for converting the processed video signal data into a required applied voltage based on the VT characteristics of the liquid crystal panel. A viewing angle interlocking control unit 3 is provided which is independent and switches and controls a plurality of γ data individually set to RGB so as to have a desired viewing angle characteristic in a predetermined pixel pattern. Further, a video feature detection unit 4 for extracting features of the input video signal is provided, and the obtained video feature information is input to the viewing angle interlock control unit 3. It is assumed that a TN liquid crystal panel whose orientation is controlled so as to have a large viewing angle dependence with respect to a desired direction is used.

The liquid crystal display device constructed as described above is shown in FIGS. 1 and 3, FIGS. 4, 5, 5, 6, 7 and 8.
The operation will be described with reference to FIG.

First, an input video signal is input to the signal control means 1 and the video feature detection means 4. Here, the signal control means 1 is a circuit for controlling the contrast and brightness of the signal independently of RGB. It is assumed that the RGB signal is input, and the gain for controlling the contrast and the offset value for controlling the brightness are set independently for RGB. This is a circuit that can be used. In addition, the video feature detection unit 4 sets the video feature information of the maximum value (hereinafter, referred to as MAX) and the minimum value (hereinafter, referred to as MIN) of the luminance for each screen of the video signal, that is, the signal range as the input signal, It can be calculated by calculation.

The video signal corrected by the signal control means 1 is input to an RGB independent γ conversion circuit 2. The RGB independent γ-conversion circuit 2 has three RGB circuits for performing γ-conversion processing by a calculation method using parameters.
The configuration is such that each of γ1 and γ2 can be set for each of the GBs, and further includes a selector for switching γ1 characteristics and γ2 characteristics as γ conversion processing. It should be noted that, by partially combining the γ conversion with the ROM table method, it is possible to obtain a γ conversion circuit in which the curve of the γ characteristic can be partially formed and the accuracy is further improved as compared with the case where only linear approximation is performed by the calculation using the parameters. it can. A signal output from the RGB independent γ conversion circuit is input to a source driver of the liquid crystal panel through a polarity inversion circuit or the like (not shown, including a DA converter, a video amplifier and the like in the case of a liquid crystal panel having an analog IF configuration). Driven.

The viewing angle interlocking control means 3 performs the following processing based on the desired viewing angle setting externally set and the image characteristic information such as MAX / MIN obtained by the image characteristic detecting means 4. First, the γ characteristics of γ1 and γ2 are set for each of RGB so that desired viewing angle characteristics can be realized. Depending on the desired viewing angle characteristics, the individual characteristics and combinations of γ1 and γ2 can be easily set, and the desired viewing angle characteristics cannot be easily obtained.
As for the characteristics, the closer the characteristics, the less the effect on the image quality. Second
Γ1, γ2 characteristics and MAX /
Optimal contrast setting and brightness setting are performed in consideration of the MIN value and the like. The details of the control by the signal control means 1 will be described in a third embodiment. Third, γ1
And γ2 are selected and controlled by selecting the most effective pattern. This switching pattern will be described in detail in Embodiments 4 and 5. By performing the three processes described above in total and performing adaptive control, effective viewing angle control can be performed in consideration of the state of the video signal.

An outline of an example of the above three main processes will be described below with reference to the drawings. FIG. 5 is a diagram showing an example of setting of the γ conversion characteristic. In the present embodiment, the case where the viewing angle is widened by signal processing and the control for narrowing or moving the viewing angle are described. FIG. 5A shows an example of the γ characteristic setting when the viewing angle is widened. Something, Figure 5
(B) is an example of a case where the viewing angle is narrowed, moved, or optimized. As for the desired viewing angle control direction, basically, the direction in which the viewing angle dependence is increased and the degree of dependence can be controlled to some extent by controlling the alignment of the TN liquid crystal panel. . The viewing angle dependence due to the alignment control is also described in, for example, Japanese Patent Application Laid-Open No. 10-319373, entitled "Liquid Crystal Display Device and Liquid Crystal Display System" described in Conventional Example 2. Here, an example in which the viewing angle is controlled in the vertical direction (an example in which the orientation is controlled so that the viewing angle dependency is greater in the vertical direction of the screen) will be described. Each VT characteristic is obtained, for example, as shown in FIG. 3. From this, for example, γ1 optimized for an upper viewing angle of 45 ° and γ2 optimized for a lower viewing angle of 30 ° are used to perform pattern control described later. By combining them, it is possible to perceptually widen the viewing angle. FIG.
As shown in (b), for example, γ1 optimized for a lower viewing angle of about 30 ° and γ2 partially different in characteristics from γ1 for a halftone portion or the like provide basic movement and optimization in each direction of the visual field. Γ control can be performed. Conversely, as shown in FIG. 4, if a γ characteristic that optimizes the upper viewing angle to 45 ° is given, as shown in FIG. It is possible to mask (black out) visual recognition from a certain direction. Similarly, masking by whiteout is also possible. FIGS. 6 and 7 show an example of the switching pattern of the γ conversion characteristic. Γ1 and γ2 set according to the control purpose and the desired viewing angle direction as described above are set for each pixel as shown in FIG. 8 shows a spatial modulation and a pattern which is time-modulated in a field unit as shown in FIG. By selecting an optimum pattern from the currently displayed image state and the viewing angle setting from such modulation patterns and switching between γ1 and γ2, more effective viewing angle control can be achieved. This content will be described in detail in Embodiments 4 and 5. However, such a control can be realized by adopting a configuration in which the view angle interlocking control means 3 can perform total control.

FIG. 8 is a schematic diagram showing an example of the control of contrast and brightness performed by the signal control means 1. When the signal range of the input signal is narrow, the amplitude is increased by the contrast gain, and the brightness is adjusted by the offset control. By performing the γ conversion process by sufficiently utilizing the dynamic range, it is possible to perform control so as to sufficiently maintain the gradation display accuracy even when performing the viewing angle control. As described above, the three basic processes as described above are interlocked by the view angle interlocking control means 3 and adaptively controlled according to the video feature information, whereby the optimum processes can be interlocked. Thus, more effective viewing angle control can be performed including video signal processing.

In this embodiment, the signal control means 1 performs only the contrast and brightness control. However, as described in the embodiment in which the upper viewing angle optimization γ is specified, the viewing angle from one direction is set. If you want to black out,
Even at the front viewing angle or the upper viewing angle, the whole image is a dark image with low luminance, but in such a case, the noise reduction processing for the video signal is set to be large,
Interlocking control such as increasing the gain of aperture processing can also provide the effect of signal processing, and it is effective to include such a signal processing circuit.

In this embodiment and the following embodiments, only two types of γ characteristics, ie, γ1 and γ2, are described. However, switching of three or more γ characteristics is also possible. It is valid.

As described above, the basic three-step processing in the above-mentioned viewing angle control can be adaptively controlled in conjunction with the state of the video signal extracted by the video feature detecting means 4. With more effective brightness,
It is possible to control the viewing angle of a mask or the like in a wide or narrow viewing angle or in one direction while suppressing image quality deterioration such as contrast and hue change.

(Embodiment 2) FIG. 2 is a block diagram of a liquid crystal display device according to Embodiment 2 of the present invention. In FIG. 2, the present liquid crystal display device performs RGB processing of contrast and brightness processing on an input video signal. A signal control means 1 capable of processing with independent settings and a γ conversion circuit 2 for converting the processed video signal data into a required applied voltage based on the VT characteristics of the liquid crystal panel are RGB-independent and have a desired viewing angle characteristic. A viewing angle interlocking control unit 3 for performing switching control of a plurality of γ data set individually for RGB in a predetermined pixel pattern so that In addition, a backlight control means 9 for controlling the backlight brightness of the backlight 8 is provided. Further, a video feature detection unit 4 for extracting features of the input video signal is provided, and the obtained video feature information is input to the viewing angle interlock control unit 3. For the liquid crystal panel, T
It is assumed that an N liquid crystal whose orientation is controlled so that the viewing angle dependence is increased with respect to a desired direction is used.

The liquid crystal display device configured as described above
A backlight control function is added to the configuration described in the first embodiment, and the operation of only the portions different from the first embodiment will be described with reference to FIGS. 2, 3, and 4. FIG. First, the video feature detection means 4 can calculate each video feature information of an average brightness value (hereinafter, referred to as APL) in addition to the brightness MAX and MIN for each screen of the video signal. I have. As a result, in the view angle interlocking control means 3, in addition to the interlocking adaptive control of the three processes described in the first embodiment, the APL is taken into consideration.
The backlight control means 9 controls the backlight brightness so as to compensate for the reduction in the brightness of the liquid crystal display that occurs in the viewing direction by controlling the viewing angle, or to control the reduction in contrast. As described above, the operation is performed so as to appropriately perform optimal processing according to the state of the input video signal and the setting of the viewing angle.

For example, in an example where the display is masked (blacked out) in the lower viewing angle direction shown in FIG.
Both of the characteristic settings γ1 and γ2 are output in a high output voltage range (in the case of a normally white TN liquid crystal), and as a result, the front viewing angle and the upper viewing angle portion are dark as a whole. . In other words, since the transmittance is generally low, in such a case, the backlight control means is controlled so as to increase the backlight luminance, and the operation is performed so as to compensate for the decrease in the luminance. For a front viewing angle or an upper viewing angle to be visually recognized, a decrease in luminance can be suppressed as compared with the case of FIG.

On the other hand, in the case of a whiteout in which the luminance becomes high as a whole, by using the backlight with a reduced luminance, the image becomes entirely whitish even in the viewing direction which should be displayed normally. Can be reduced. This case is effective from the viewpoint of reducing the power consumption of the backlight. Further, in cases other than the control of the viewing angle limitation, for example, in the example shown in FIG.
, And the luminance of the backlight can be reduced such that the visual APL of the input video signal and the output signal becomes equal. Further, γ conversion characteristics γ1 and γ2
In order to change to the desired viewing angle characteristics, such as when the static characteristics of the device itself or the switching pattern is asymmetrical in area between γ1 and γ2, there is a large variation in the light transmittance of each pixel of the liquid crystal element. In some cases, flexible control can be performed by controlling the backlight luminance while considering the APL and the trade-off with the viewing angle control effect.

With respect to the relationship between the APL and the backlight control amount, for example, when γ is average or when γ is higher than the transmittance, the backlight brightness is decreased when the APL is higher, and when γ is lower than the low transmittance. In the case of (1), if the value of APL is high, a control method such as performing control in a direction of increasing the backlight luminance is given as an example. However, various controls may be considered depending on the case.

The backlight control amount and the contrast and brightness control amounts for the signal control unit 1 set by the viewing angle interlocking control unit 3 by reflecting the image characteristic information detected by the image characteristic detection unit 4 are as follows. The video feature information extracted by the video feature detection means 4 is statistically processed at predetermined time intervals to calculate scene discrimination information of the video.
By a method such as adjusting the time constant from the scene determination information through an IR filter, adaptive control can be performed in consideration of the time direction of the video signal, and more effective control can be realized.

As described above, each of the three basic processes in the viewing angle control described in the first embodiment, in addition to the control of the backlight luminance, is performed by the video feature detecting means 4.
The structure is such that it can be adaptively controlled in conjunction with the state of the video signal extracted by the above, so that even if the viewing angle is controlled, the contrast does not decrease and the backlight does not increase the backlight brightness more than necessary. While suppressing the power consumption, it is possible to realize a viewing angle control of a mask or the like in a wide or narrow viewing angle or in one direction while compensating for a decrease in luminance.

(Embodiment 3) Interlocking control of contrast adjustment, brightness adjustment and γ characteristic setting by the signal control means 1 of the liquid crystal display device according to Embodiment 3 will be described with reference to FIGS. 3, 8, and 9. I do.

First, a basic control method of contrast adjustment and brightness adjustment in this embodiment will be described. The video feature detection means 4 calculates the MAX and MIN of the luminance of the input video signal for each screen by calculation, whereby the brightness range of the video signal can be processed in all signal processing for each screen. You need to know where you are in the range. In FIG. 8, the input signal is M
If the range is between IN and MAX, gain control is performed to widen the dynamic range as signal processing, and the amplitude is expanded as shown in the contrast control of FIG. In this example, since the signal is on the MIN side, the MI
Since the signal processing range is exceeded on the N side, offset control can be performed as in the brightness control shown in FIG. 3 to adjust the dynamic range to the maximum. As the contrast control, as shown in an example of the contrast control characteristic in FIG. 9, a natural contrast control can be performed by performing a contrast control having a gain characteristic as shown in the figure for the difference between MAX and MIN. it can.

Actually, in the viewing angle control, as described in the first and second embodiments, the optimum γ characteristic is adjusted so as to be close to the desired viewing angle characteristic according to the VT characteristic shown in FIG. 5 (a) and 5 (a).
The horizontal axis of (b) shows the input voltage, which is actually the correction data from the signal control means 1, so that the γ characteristic as shown in FIG. In order to control the viewing angle by making the most of the change in the transmittance, it is more advantageous to obtain the maximum amplitude of the output data of the signal control means 1 within the range in which the signal can be processed.

When the viewing angle control amount is small and, for example, the viewing angle is used only in a good narrow viewing angle range such as 0 ° ± 20 ° near the front viewing angle, the desired VT characteristic is a good VT characteristic. Since the characteristics are close to the characteristics, a display with good gradation characteristics can be performed even as a γ conversion characteristic using only a portion having good gradation characteristics. in this way,
The optimal control of how the input corresponding to the horizontal axis in FIG. 5 corresponds to the variable range of the signal differs depending on the content and the control amount of the viewing angle control. It can be seen that there is an advantage of controlling the contrast and brightness control and the γ characteristic setting in accordance with the state.

However, if the γ conversion characteristic is set by adjusting the contrast and brightness at an excessively or extremely short interval while giving priority only to the viewing angle control, the original image state of the input image signal is remarkably changed. It may not be a video. On the other hand, the video characteristics of the video signals displayed on the liquid crystal panel generally depend largely on the signal source. For example, images of personal computers and car navigation systems have a large dynamic range and many signals with high contrast. Has many halftone signal components.

Therefore, in consideration of the above points, the combination of the control amount of the signal control means 1 and the γ conversion characteristic is generally set in accordance with the source of such a video signal, and the actual video state is changed. Effective control can be realized by performing fine adjustment obtained by the image feature detection means 4.

Further, as described in the second embodiment,
Regarding the contrast and brightness control amounts for the signal control unit 1, scene determination information of an image obtained by statistically processing the image feature information extracted by the image feature detection unit 4 at predetermined time intervals is calculated, and the contrast gain and the like are calculated. Change in the time direction of the video signal (scene change) by a method such as adjusting the time constant based on the scene discrimination information through an IIR filter having a time constant for the control amount such as brightness and gamma parameter.
Adaptive control in consideration of

As described above, the viewing angle control can be efficiently performed based on the relationship between the specified viewing angle control content and the control amount and the variable range of the brightness of the input video signal, and the optimum brightness can be further improved. Contrast control and γ as obtained
By performing the characteristic setting, it is possible to realize a viewing angle control with less image quality deterioration such as a decrease in contrast due to controlling the viewing angle.

(Embodiment 4) In the viewing angle interlocking control means 3 of the liquid crystal display device according to Embodiment 4, the switching pattern control in one screen of a plurality of γ characteristics performed for the RGB independent γ conversion circuit will be described. 6 will be described.

FIG. 6 shows an example of a switching pattern of the γ conversion characteristic. As described in the first and second embodiments, a plurality of γ characteristics different from each other so that the viewing angle characteristic becomes a desired viewing angle characteristic. FIG. 7 is an explanatory diagram of a switching pattern in a pixel unit for one screen (one field) in the present method of controlling the viewing angle by setting the pixel width for each predetermined pixel. FIG. 6A shows γ1 and γ2 alternately in the horizontal pixel direction and γ1 and γ also in the vertical direction in units of RGB trios.
FIG. 6B shows an example in which γ1 and γ2 are alternately switched in the horizontal pixel direction and the columns are switched in the vertical direction, and FIG.
(C) shows a single γ of γ1 or γ2 in the horizontal pixel direction.
This is an example in which switching is performed in a horizontal stripe shape in which γ1 and γ2 are alternately switched between scanning lines in the vertical direction. These are all RG
The same γ is set for a set of B trios.
Γ1 for G and γ1 for B or γ2 for R and γ2 for G
Embodiments 1 and 2, even if the same γ2 is the same γ1 and γ2,
3 are different from each other.

Here, in the present invention, the first feature of this spatial modulation is that, as shown in FIG. 6 (d), three points in FIGS. 6 (a), 6 (b) and 6 (c) are used. A pattern in which the patterns such as the example are switched so that γ1 and γ2 are asymmetrical is also used appropriately. FIG.
In (d), using the RGB trio as a unit of one pixel, γ1 and γ2 are not alternately switched in the horizontal pixel direction, but γ1 is alternately switched in two pixels and γ2 in one pixel. In this example, γ1 is alternately switched between one pixel and γ2 is alternately switched between two pixels. Also in this case, γ1 and γ2 are different in RGB. In this example, although the appearance is irregular, the appearance frequency of γ1 and γ2 in one screen is the same, but it is not shown, but it is not shown, but is a stripe shape as shown in FIGS. 6 (b) and 6 (c). The appearance frequency of γ1 and γ2 in one screen (the area of γ1 pixel and γ2 pixel in one screen) is also asymmetric, such as the asymmetric switching pattern in FIG. An example is also considered. In the case of a pattern having a very irregular pattern, the influence of adverse effects such as flicker can be considered. However, it depends on the characteristics of γ1 and γ2 to be switched and the input signal state as described below. In many cases, this is not a problem and is effective.

The intention of these patterns is that the main pixel and the sub-pixel which can have optimum viewing angle characteristics in the capacitive coupling pixel division method as disclosed in Japanese Patent Application Laid-Open No. Hei 8-201777. As can be easily understood from an example in which the area ratio and the voltage ratio are asymmetric (for example, 2: 1), the most effective is obtained from the relationship between the set γ characteristics γ1 and γ2 characteristics (difference). This is because the ratio at which the viewing angle characteristic can be controlled in a short time is not necessarily the area ratio of 1: 1. For example, in the case of a normally white TN liquid crystal, γ
When the voltage ratio between 1 and γ2 is approximately 2: 1, there is a case where the optimum area ratio is about 7: 3 in the above-described capacitive coupling pixel division method.

As described above, the first feature of the spatial modulation of this embodiment is that the pattern is controlled in asymmetric pixel units. Note that the viewing angle control described in the present embodiment is based on the assumption that the number of pixels is equal to or larger than the wide VGA class.

Next, the second feature of the spatial modulation of the present embodiment is that the switching pattern and the γ characteristics γ1 and γ2 to be switched
An object is to appropriately control the switching pattern and the γ characteristic appropriately in accordance with the video state of the input signal and the intended viewing angle control content.

For example, in the image feature detecting means 4, 1
The appearance frequency of the high-frequency component of the input video signal is detected for each screen, and FIG. 6 (a) is selected as a pattern for a video requiring resolution according to the fineness of the video of the input signal. By switching to the pattern of FIG. 6D, selection according to the characteristics of the input video signal is possible.

As a simple means, a pattern shown in FIG. 6A is selected for each source of an input video signal, for example, for a personal computer screen or a car navigation screen, and FIG. ) May be switched for each source of the input video signal.

Further, not only the state of the input video signal, but also the number of pixels of the liquid crystal panel to be used, the size of one pixel (square or rectangular), or the screen mode of the display screen (particularly a liquid crystal display device having a wide screen size) In this case, the optimum switching pattern may be appropriately selected for each screen also in the aspect ratio of (screen size in wide aspect display, two-screen display, etc.). Further, an optimal switching pattern may be appropriately selected according to a scanning line format or a scanning line conversion process in which an input video signal is an interlace signal or a non-interlace signal.

As described above, the so-called spatial modulation pattern, which is switched for each pixel in the horizontal or vertical direction of one screen, is not only an alternating pattern for each pixel but also an asymmetric shape. It contributes to the area effect to give γ1 and γ2, and the optimum modulation pattern can be obtained by the effect of combination with the difference of γ characteristics.

Furthermore, by using this pattern modulation in which the state of the video signal input to the viewing angle interlocking control means 3, the input source or screen configuration, and the configuration of the liquid crystal panel to be displayed are totally taken into account, visually natural It is possible to realize a viewing angle control which is always optimal, has no adverse effects, and suppresses image quality deterioration such as luminance reduction.

(Embodiment 5) In the viewing angle interlocking control means 3 of the liquid crystal display device according to the embodiment 5, the plurality of γ characteristics performed on the RGB independent γ conversion circuit 2 in the field direction (time axis direction). The switching pattern control will be described with reference to FIGS. FIG. 7 shows an example of a switching pattern of the γ conversion characteristic in the time axis direction.
The spatial modulation pattern described in the fourth embodiment corresponds to one screen (1
FIG. 9 is an explanatory diagram of a method of switching patterns between fields, which is a pixel switching pattern for (field), but is also extended in the time axis direction. In FIG. 7, FIG.
For the pattern of (d), from the n-th field to the (n + 5) -th
FIG. 7B shows the switching pattern up to the field. In the (n + 1) th field in FIG. 7B, the same pattern as the nth field in FIG.
The field has only one field having a γ characteristic opposite to the n-th field in FIG. 7A, and the same pattern as the n-th field in the n + 3 and n + 4 fields in FIGS. 7D and 7E. Is to repeat. All of these have the same γ as a set of RGB trios,
Γ1 for R, γ1 for G, and γ1 for B or γ2 for R, γ2 for G, and γ2 for B are the same as described in the fourth embodiment, even if they are the same γ1 and γ2.

Here, the first feature of the time base modulation in the present invention is that the time axis modulation is appropriately used for a pattern which is switched to be asymmetrical on a field basis as in the example of FIG. 7 described above. Is about to do. The intention of these anomalous patterns is the same as that described in the fourth embodiment, in that the pixel that becomes γ1 and the γ2
The effect on the viewing angle control can be expected in view of the balance between the respective γ characteristics and the response speed of the liquid crystal panel due to the integration effect of the pixels.

The reversal of .gamma.1 and .gamma.2 in the field direction described with reference to FIG. 7 largely depends on the response speed of the liquid crystal panel in terms of the image quality and the effect of the viewing angle control. It is necessary to Regarding the modulation in the time axis direction, if the pattern is too irregular, the influence of the adverse effects such as flicker can be considered, but as described below, the priority is placed on the viewing angle control in the video where the adverse effects are not conspicuous. By performing adaptive control according to the state of the video signal, for example, it is possible to perform viewing angle control signal processing with minimum adverse effects. As described above, the first feature of the time modulation of the present invention is that the pattern is controlled in asymmetric field units. Note that the viewing angle control described in the present embodiment also assumes that the number of pixels is equal to or larger than the wide VGA class. Next, the second feature of the time modulation of the present embodiment is that the switching pattern and the switching γ
The characteristics γ1 and γ2 are determined by the viewing angle interlocking control means 3 in accordance with the video state of the input signal, the scanning line format of the video signal, the scanning line conversion processing, or the intended viewing angle control content. It is to control the characteristics.

For example, the motion of the input video signal is detected by the video feature detecting means 4 to detect the speed and amount of the motion of the video signal, and the motion of the input signal is converted into a still image or almost a still image depending on the amount of motion of the video of the input signal. In a close image, a pattern symmetrical in the field direction is used to reduce flicker.
In addition, the reversal interval is made short, and in the case of a video with a lot of movement, the influence of flicker or the like may not be noticeable, and it may be effective to select a pattern as shown in the example of FIG. Since these are closely related to the response speed of the liquid crystal panel to be used, it is effective to flexibly select a pattern according to the state of the input video as described above.

Further, a scanning line format such that an input video signal is an interlaced signal or a non-interlaced signal, and an optimal switching pattern as appropriate according to a scanning line conversion process processed by a video signal processing unit accordingly. You may choose. As an example, when an interlace signal is input, an asymmetric pattern as shown in FIG. 7 is effective, and when a progressive conversion process is performed in a video signal processing unit, it is necessary to appropriately select a pattern according to the processing content. it is conceivable that. As a simple means, for example, for a personal computer screen or a car navigation screen for each source of an input video signal, it is considered that the state is relatively close to a still image, and the above-described processing for a still image is performed. , TV video, etc., may be switched for each source of an input video signal, such as performing processing suitable for a moving image.

As described above, the pattern for switching the γ characteristic in the field direction (time axis direction), that is, the so-called time modulation pattern, is not limited to the pattern that is alternated every field at a predetermined interval. The asymmetrical shape allows the area effect to give γ1 and γ2 to be extended three-dimensionally, and the integration effect makes it possible to perceptually combine the difference with the γ characteristic to obtain the optimum modulation pattern. it can. Further, the modulation of the pattern is performed in consideration of the state of the video signal input to the viewing angle interlocking control means 3, the input source, the scanning line configuration and the scanning line conversion processing or the screen configuration, and the liquid crystal panel configuration to be displayed. Allows for a visually natural modulation,
It is possible to realize the viewing angle control which is always optimal, has no adverse effects, and suppresses the deterioration of the image quality such as the luminance reduction.

(Embodiment 6) FIG. 10 is a block diagram showing the configuration of a liquid crystal display device according to Embodiment 6 of the present invention.
In FIG. 10, the present liquid crystal display device can individually operate the signal control unit 1, the image feature detection unit 4, the view angle interlocking control unit 3, and the RGB independent γ conversion circuit for each input signal display area. By inputting a signal for identifying a display area of an input video signal to each circuit, the viewing angle interlocking control for each display area can be performed as a whole.

The operation of the liquid crystal display device configured as described above will be described with reference to FIG.

Here, a case of two-screen display of a main screen and a sub-screen will be described. First, the display area-specific video feature detection means 4 has two circuits for calculating video features such as the maximum value, the minimum value, and the average value of the video signal, and a signal for identifying the area of the main / sub video signal (hereinafter referred to as a signal). , Main and sub area selection signal)
Thus, each feature amount is independently calculated. The display area-dependent RGB independent signal control means 1 and the display area-dependent RGB independent γ conversion circuit 2 respectively perform parameter setting values for calculating a plurality of γ characteristics such as contrast, brightness, and RGB for the main screen and the sub-screen. The operation is switched by a main / sub area selection signal. The display area-specific view angle interlocking control means 3 also performs the interlocking control described in Embodiments 1 and 2 individually by the main and sub area selection signals, so that each of the main screen and sub screen image areas is controlled. Then, each circuit is operated so that a liquid crystal display having different viewing angle characteristics is set.

As for the backlight control, not only the same control as described in the second embodiment is performed, but also
If the average value of the main screen and the sub-screen is significantly different from each other (such as a bright image and a dark image), the backlight control is performed on either the main screen or the sub-screen. Screens not controlled (for example, sub-screen when backlight control is performed on main screen video)
For the main screen, the correction data is generated from the backlight control data on the control target side so that the control effect of the backlight is canceled, and the contrast and brightness of the non-control target screen are adjusted. Even in the case of an image whose luminance state is largely different between the sub-screen and the sub-screen, it is possible to prevent the influence of the backlight control accompanying the viewing angle control from appearing on the other screen.

Although the present embodiment has been described with respect to an example of a main / sub two-screen display, even in the case of a multi-screen having three or more screens, the required number of circuit circuits are similarly provided for the image feature detecting means 4. The signal control means 1, the viewing angle interlocking control means 3, and the RGB independent γ conversion circuit 2 are configured so that parameters can be set for each display area, and are switched by a display area selection signal, so that each of the display screens is changed. The viewing angle characteristics can be individually controlled.

In an application such as an in-vehicle TV having a two-screen display function, in which the TV display and the car navigation display are optimized in different viewing angle directions, the use of this function enables the driver to make a request from the driver side while driving. An application such as masking the screen of an in-vehicle TV in the direction of the viewing angle to improve safety on road traffic is also possible.

As described above, even when a plurality of screens are displayed in one screen such as two-screen display, multi-screen display, and PinP, the viewing angle characteristics are individually controlled for each display screen. Can be realized.

[0073]

As apparent from the above description, according to the present invention, a special liquid crystal cell for controlling a viewing angle is used, an optical lens sheet is controlled, and the optical characteristics of a backlight are changed. In a liquid crystal display system in which the viewing angle is controlled only by an external signal processing circuit without using such means, use conditions such as when viewing angle conditions are limited, input source signal, video signal form, display By appropriately performing the optimal interlocking control according to the video content and the like, it is possible to realize the optimal viewing angle control that suppresses the image quality degradation, the concealment of the display content, the optimization of the viewing direction, and the like.

In particular, by performing adaptive control in which the respective processes are linked in accordance with the video feature information of the video signal, it is possible to suppress deterioration in image quality such as a decrease in brightness and contrast, a flicker, a change in hue, and the like due to the control of the viewing angle, and Viewing angle control such as widening and narrowing of the viewing angle, movement, masking in a specific direction, and optimization of the viewing direction can be effectively performed. In addition, by adopting adaptive control for the backlight, effective viewing angle control can be performed without lowering the contrast and brightness, and power consumption can be reduced by suppressing a decrease in light use efficiency of the backlight. It is possible.

Further, in a system application, it is possible to obtain an optimum configuration in applications such as optimizing a TV display and a car navigation display in different viewing angles in a vehicle-mounted TV with a two-screen display function. It is.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 3 is a characteristic diagram showing an example of VT characteristics of a TN liquid crystal display device.

FIG. 4 is a characteristic diagram showing an example of luminance characteristics by setting γ conversion characteristics of the liquid crystal display device according to the first and second embodiments of the present invention.

FIG. 5 is a characteristic diagram showing an example of setting of γ conversion characteristics of the liquid crystal display device according to the first and second embodiments of the present invention.

FIG. 6 is a diagram showing an example of a γ switching pattern in one screen in the γ conversion circuit of the liquid crystal display according to the first to fifth embodiments of the present invention.

FIG. 7 is a diagram showing an example of a γ switching pattern in the field direction in the γ conversion circuit of the liquid crystal display according to the first to fifth embodiments of the present invention.

FIG. 8 is a schematic diagram showing an example of contrast and brightness processing in the signal control means of the liquid crystal display according to the first to third embodiments of the present invention.

FIG. 9 is a characteristic diagram showing an example of a contrast control characteristic in a signal control unit of the liquid crystal display according to the third embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a liquid crystal display device according to a sixth embodiment of the present invention.

FIG. 11 is a block diagram illustrating a configuration of a liquid crystal display device of Conventional Example 1.

FIG. 12 is a schematic diagram illustrating a γ switching pattern shown in Conventional Example 1.

FIG. 13 is a characteristic diagram showing an example of γ characteristic setting shown in Conventional Example 1.

FIG. 14 is a block diagram illustrating a configuration of a liquid crystal display device of Conventional Example 2.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 RGB independent signal control means 2 RGB independent γ conversion circuit 3 view angle interlocking control means 4 image feature detection means 5 gate drive circuit 6 alignment direction control liquid crystal panel 7 source drive circuit 8 backlight 9 backlight control means

Continued on front page F-term (reference) 2H093 NA16 NA51 NC42 NC52 ND03 ND07 ND10 ND13 ND39 ND60 NF05 5C006 AA22 AC02 AF23 AF63 BB16 BC03 BC06 BC13 EA01 EC09 FA22 FA23 5C080 AA10 CC03 DD03 DD06 DD30 EE28 EJ20 KK02

Claims (12)

[Claims] 1. A drive circuit for an active matrix drive type liquid crystal display element and a liquid crystal display device in a backlight system, comprising: a signal control means for performing video signal processing on an input video signal; RGB independent gamma conversion means capable of independently setting a gamma conversion process for converting an input value into a liquid crystal application voltage with a plurality of different characteristics for each of RGB, and RGB independent gamma conversion means for obtaining desired viewing angle characteristics. A viewing angle interlocking control unit that controls each gamma data setting and a switching pattern thereof; and a video feature detecting unit that extracts a feature of an input video signal and outputs video feature information to the viewing angle interlocking control unit. A liquid crystal display device characterized by the above-mentioned. 2. The liquid crystal display device according to claim 1, further comprising backlight control means for controlling the backlight brightness of the liquid crystal panel by the viewing angle interlocking control means. 3. The signal control unit and the RGB independent control unit so that the viewing angle interlocking control unit optimizes the display image based on the video feature information obtained from the video feature detection unit and effectively controls the viewing angle. 3. A liquid crystal display device according to claim 1, wherein each gamma data setting of the gamma conversion means and its switching pattern control and backlight control are dynamically and adaptively controlled in conjunction with each other. 4. The signal control means performs contrast adjustment and brightness adjustment.
Obtain the maximum and minimum values of the video signal luminance for each screen,
According to the luminance range of an input signal in one screen and desired viewing angle characteristics, contrast and brightness control are performed so that the dynamic range of the gamma characteristics can be maximized or the viewing angle control can be performed most efficiently. The liquid crystal display device according to claim 1, 2 or 3, wherein: 5. The apparatus according to claim 4, wherein said signal control means is capable of independently controlling each of RGB, and corrects a shift between RGB of gamma characteristics in one-to-one correspondence with said RGB independent gamma conversion means. 3. The liquid crystal display device according to 1. 6. A switching pattern of a plurality of gamma characteristics and each gamma data to be performed on the RGB independent gamma conversion means in the view angle interlocking control means are alternately symmetrically or asymmetrically for each horizontal or vertical pixel on one screen. 2. A control method comprising selecting a pattern according to image characteristic information obtained from image characteristic detecting means and a viewing angle setting, and combining gamma data so as to be optimal. Item 6. A liquid crystal display device according to any one of items 5. 7. A switching pattern of a plurality of gamma characteristics and each gamma data to be performed on the RGB independent gamma conversion means in the viewing angle interlocking control means may be selected from among patterns which are symmetrically or asymmetrically alternate with respect to the field direction. The control according to any one of claims 1 to 5, wherein the control is performed in accordance with the video feature information obtained from the detection means and the viewing angle setting, and the gamma data is combined so as to be optimal. Liquid crystal display device. 8. An average value of luminance of a video signal is obtained for each screen by a video feature detecting means, and backlight control is performed by the signal controlling means and the RGB independent gamma converting means to change to a desired viewing angle characteristic. 4. The liquid crystal display device according to claim 3, wherein when the light transmittance of each pixel of the liquid crystal element greatly fluctuates, control is performed so as to compensate for the luminance while considering the average value. . 9. The image feature detecting means, the signal controlling means, the RGB independent gamma converting means and the viewing angle interlocking controlling means have means for individually controlling each image display area,
Even when displaying multiple screens simultaneously in one screen,
9. The liquid crystal display device according to claim 1, wherein the viewing angle characteristics can be individually controlled for each display screen. 10. A backlight control for a backlight control means is performed on any one of the plurality of display screens, and a backlight control is performed on a display screen other than a target on which the backlight control is performed. 10. The liquid crystal display according to claim 9, wherein correction data is generated from the backlight control data on the control target side so as to cancel the control effect of the light, and the signal control means of the non-control target display screen is controlled. apparatus. 11. A pattern which is alternately set symmetrically or asymmetrically for each pixel in a horizontal direction or a vertical direction of one screen is determined according to a pixel size of a liquid crystal panel or an aspect ratio of a display screen. Claim 6
3. The liquid crystal display device according to 1. 12. A pattern which is alternately set symmetrically or asymmetrically for each pixel in a horizontal direction or a vertical direction of one screen, and a pattern which is alternately set symmetrically or asymmetrically with respect to a field direction is a sequence of input video signals. The liquid crystal display device according to claim 6, wherein the liquid crystal display device is determined according to scanning, interlaced scanning, or scanning line conversion processing in signal processing.