JP2003295156A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device capable of adjusting the percentage occupied by a non-video signal period in a single frame period. <P>SOLUTION: When an observer perceives a blur of an image generated when displaying a moving image, he/she uses a black insertion rate setting part 40 and instructs a control circuit 36 to set a black insertion rate showing the percentage occupied by the black insertion period for supplying a black display signal (non-video signal) to image electrodes 39 within a single frame period. The control circuit 36 instructed from the observer via the black insertion rate setting part 40 outputs respective control signals to a gate driver 34 and a source driver 35 to alter the length of the black insertion period according to the instruction. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device for writing a non-video signal different from a video signal, and more particularly to adjusting a ratio of a non-video signal period for writing the non-video signal in one frame period. The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of space saving, etc.
Liquid crystal display devices are rapidly becoming widespread as image display devices. Most of such liquid crystal display devices are of a twisted nematic (TN) mode. However, the TN-mode liquid crystal display device is not suitable for displaying moving images because of the slow response speed of liquid crystal molecules, and has a problem that the viewing angle is narrow. Therefore, various attempts have been made for the purpose of improving the response speed of liquid crystal molecules, expanding the viewing angle, and the like.

As one of such attempts, in order to provide a liquid crystal display device having a high-speed response suitable for displaying a moving image,
A liquid crystal display device of an OCB (Optically Compensated Birefringence) mode has been proposed (see The Institute of Electrical Communication, IEICE Technical Report, EDI98-144, p. 199).

In such an OCB mode liquid crystal display device, two substrates each having a transparent electrode as a voltage applying means are formed, a liquid crystal layer sandwiched between these substrates, and a position of the liquid crystal layer. It has a liquid crystal display element composed of a retardation film or the like for compensating for the retardation. Alignment films are respectively formed on the transparent electrodes, and these alignment films are subjected to an alignment treatment so that liquid crystal molecules injected into the liquid crystal device are aligned in parallel and in the same direction. .

The liquid crystal display device constructed as described above is
It is characterized in that the alignment state of the liquid crystal molecules is transferred from so-called splay alignment to bend alignment by applying a relatively high voltage, and image display is performed by this bend alignment state. In such an OCB mode liquid crystal display device, the response speed of the liquid crystal molecules is remarkably improved as compared with the case of the TN mode, and thus it is suitable for displaying a moving image.
Further, the liquid crystal molecules in the bend alignment state are tilted in opposite directions on the upper and lower surfaces of the glass substrate, so that optical compensation is performed. Further, the retardation film described above compensates for the retardation of the liquid crystal layer. As a result, a wider viewing angle than that in the TN mode can be obtained.

By the way, as described above, in the OCB mode liquid crystal display device, the alignment state of the liquid crystal molecules is changed from the splay alignment to the bend alignment in order to display an image.
However, when the voltage required to maintain such bend alignment is not applied for a long period of time, the alignment state of the liquid crystal molecules may reversely transition to the initial splay alignment. In this splay alignment state, image defects such as alignment defects or point defects occur, and good image display cannot be performed.

In addition, when a moving image is displayed, the image may appear blurred due to the afterimage of the image of the preceding frame.

In order to prevent such a reverse transition of the alignment state of liquid crystal molecules and blurring of an image, a non-video signal, which is a signal different from a video signal, is applied to a pixel electrode for a certain period (hereinafter referred to as a non-video signal period). A liquid crystal display device designed to be written in is being researched. Although the non-video signal is not uniquely determined here, for example, normally displaying white display when a relatively low voltage is applied and black display when a relatively high voltage is applied. In the white mode, a signal for displaying black is used as a non-video signal. Then, by writing this non-video signal within a predetermined fixed non-video signal period, a relatively high voltage is applied to the pixel electrode, so that the bend orientation can be maintained. Further, since the afterimage is eliminated by the black display, it becomes possible to prevent the blurring of the image.

[0009]

The bend alignment state of liquid crystal molecules is not the same for each liquid crystal display element due to variations in the manufacturing process of the liquid crystal display element. Therefore, the non-video signal period suitable for preventing the reverse transition from the bend alignment to the splay alignment depending on each liquid crystal display element is not constant.

In addition, when the liquid crystal display device is used at a high temperature and when it is used at a low temperature, when the liquid crystal display device is used at a high temperature, the liquid crystal molecules are more likely to move. Transfer is easy to occur. Therefore, the non-video signal period suitable for preventing the reverse transition is not constant depending on the usage environment of the liquid crystal display device.

Further, when a still image is displayed instead of a moving image, the blur of the image as described above does not occur, so that the period for writing the non-video signal can be short.
Therefore, it is desirable to make the non-video signal period different between when there are many moving image displays and when there are many still image displays.

However, as described above, in the conventional liquid crystal display device, the non-video signal period is set to a predetermined fixed period, so that the period may not always be appropriate.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a liquid crystal display device capable of adjusting the ratio occupied by the non-video signal period within one frame period. is there.

[0014]

In order to solve the above-mentioned problems, a liquid crystal display device of the present invention has a plurality of pixel electrodes arranged in a matrix and a plurality of pixel electrodes respectively provided corresponding to the pixel electrodes. A liquid crystal display element having a switching element is provided, and a video signal input from the outside and a non-video signal different from the video signal are supplied to the pixel electrodes by driving the switching element in one frame period. In a liquid crystal display device that performs display according to the video signal and the non-video signal using the liquid crystal display element, a non-video signal period for supplying the non-video signal to the pixel electrode is within one frame period. It is characterized by comprising an adjusting means for adjusting the occupying ratio (claim 1).

With such a configuration, it is possible to appropriately change the ratio occupied by the non-video signal period within one frame period. Therefore, for example, when a large number of moving images are displayed or a large number of still images are displayed, an appropriate ratio can be set according to the usage status of the liquid crystal display device.

Further, in the liquid crystal display device according to the present invention, the liquid crystal display element may have liquid crystal molecules that are in a bend orientation when the display is performed (claim 2). As a result, it is possible to realize a liquid crystal display device using an OCB mode liquid crystal display device, which can appropriately change the ratio of the non-video signal period in one frame period. Therefore, for example, it is possible to set, for each individual liquid crystal display element, the ratio suitable for preventing the reverse transition from the bend alignment to the splay alignment.

Further, in the liquid crystal display device according to the present invention, an illuminating device having a light source for emitting red, green, and blue light, respectively, and the light source for emitting each color light in a time-division manner within one frame period. A lighting device control means for controlling the lighting device may be further provided (claim 3).

With such a structure, it is possible to realize a field-sequential color liquid crystal display device capable of appropriately changing the proportion of the non-video signal period in one frame period.

Further, the liquid crystal display device according to the present invention further comprises a receiving means for receiving the input of the ratio information indicating the ratio, and the adjusting means sets the ratio information to which the input is received by the receiving means. It may be configured to adjust the ratio based on the above (claim 4).

With such a structure, for example, an observer who observes the liquid crystal display device can input the desired ratio using the accepting means. As a result, it is possible to perform display according to the preference of the observer.

It is also possible for the manufacturer of the liquid crystal display device to input the desired ratio using the reception means. This allows the liquid crystal display device to be shipped after setting the appropriate ratio for each liquid crystal display device.

Further, in the liquid crystal display device according to the present invention, a storage unit for storing a plurality of ratio information indicating the ratio, and a selection for selecting a specific ratio information from the ratio information stored by the storage unit. And means,
The adjusting unit may be configured to adjust the ratio based on the ratio information selected by the selecting unit (claim 5).

With such a configuration, for example, an observer observing the liquid crystal display device can select a desired one from a plurality of ratio information and change the ratio based on the selected ratio information. Becomes

Further, in the liquid crystal display device according to the present invention, a temperature sensor for measuring a temperature in the vicinity of the liquid crystal display element is further provided, and the adjusting means adjusts the ratio based on a measurement result of the temperature sensor. It may be configured to do so (Claim 6).

With such a structure, when the liquid crystal display device is used at a high temperature at which a reverse transition from the bend alignment to the splay alignment is likely to occur because the liquid crystal molecules are easily moved,
The ratio can be set so as to prevent the reverse transition. Therefore, it is possible to maintain a good display.

In the liquid crystal display device according to the present invention, the adjusting means may be configured to adjust the ratio within a range of 5% or more and 75% or less (claim 7). This makes it possible to ensure the appropriate ratio and prevent the ratio from being set to an inappropriate value due to an error of an observer or the like who observes the liquid crystal display device.

Further, in the liquid crystal display device according to the present invention, an applying means for applying a voltage to the liquid crystal display element for causing the liquid crystal molecules to transition from the splay alignment to the bend alignment, and the voltage to the liquid crystal display element are applied. The configuration may further include an instruction unit used to instruct the application unit to apply the voltage (claim 8).

With such a structure, even when the alignment state of the liquid crystal molecules reverses from the bend alignment to the splay alignment due to the application of a relatively low voltage, for example,
By instructing the voltage to be applied to the liquid crystal display element by the instructing means, the transition to the bend alignment can be easily performed.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) In the liquid crystal display device according to the first embodiment of the present invention, the ratio of the non-video signal period for supplying the non-video signal to the pixel electrode in one frame period is set to an arbitrary value. It can be adjusted to. In addition,
In the present specification, including other embodiments described later, the non-video signal is a black display signal. Therefore, below, the above-mentioned ratio will be referred to as a black insertion ratio.
Further, the non-video signal period will be referred to as a black insertion period.

FIG. 1 is a sectional view showing an example of the configuration of a liquid crystal display element (liquid crystal panel) included in the liquid crystal display device according to the first embodiment of the present invention. Further, FIG. 2 is a cross-sectional view schematically showing an alignment state of liquid crystal molecules included in the liquid crystal display element described above. For convenience of explanation, the X direction in the drawing is the upward direction of the liquid crystal display device.

As shown in FIG. 1, the liquid crystal display element 100 included in the liquid crystal display device according to the present embodiment has two substrates, that is, an upper substrate 101 and a lower substrate 102 with a spacer (not shown) interposed therebetween. The liquid crystal layer 4 is disposed in a gap formed between the upper substrate 101 and the lower substrate 102. Liquid crystal molecules 20 are injected into the liquid crystal layer 4 as described later with reference to FIG.

The upper substrate 101 is formed by laminating the transparent electrode 2 and the alignment film 3 on the lower surface of the glass substrate 1 in this order. The lower substrate 102 is formed by stacking the transparent electrode 6 and the alignment film 5 in this order on the upper surface of the glass substrate 7. The upper substrate 1 is used for color display.
01 between the glass substrate 1 and the transparent electrode 2,
Color filters (not shown) for each of the three primary colors of light, red, blue, and green, are provided.

On the upper surface of the upper substrate 101, a retardation film 8 for compensating the retardation of the liquid crystal layer 4 is provided.
Is provided. Similarly, the retardation film 9 is provided on the lower surface of the lower substrate 102.

Further, a polarizing plate 10 is arranged on the upper surface of the retardation film 8, and a polarizing plate 11 is arranged on the lower surface of the retardation film 9.

The liquid crystal display device 100 thus constructed
In the initial state, the liquid crystal molecules 20 are in the splay alignment as shown in FIG. The liquid crystal display device according to the present embodiment changes the alignment state of the liquid crystal molecules 20 from the splay alignment described above to the bend alignment as shown in FIG. 2B by applying a predetermined voltage to the liquid crystal display element 100. Transfer. Then, image display is performed in this bend orientation state. That is, the liquid crystal display element 100 has an OC
This is called B mode.

The liquid crystal display element 100 is not limited to the OCB mode, and may be, for example, TN (Twisted-Nema).
The liquid crystal display device of other modes such as the tic mode may be provided.

The liquid crystal display element 100 is a normally white mode display element. That is, white display is performed when a relatively low voltage is applied, and black display is performed when a relatively high voltage is applied. Therefore, when the black display signal is written,
Since a relatively high voltage is applied to the pixel electrode, the bend orientation can be maintained. Further, since the afterimage is eliminated by the black display, it is possible to prevent the blurring of the image.

Further, the liquid crystal display element 100 is a dot inversion drive type display element in which the voltage polarity of the video signal or the black display signal is inverted for each dot in order to prevent flicker.

FIG. 3 is a block diagram showing the configuration of the liquid crystal display device according to the first embodiment of the present invention. 1 and 2
Referring also to, the liquid crystal display element 100 is a well-known TFT (Thin Film Transistor) type display element, and includes a counter substrate (not shown) having a common electrode (not shown) formed on its inner surface, A TFT in which a pixel electrode 39, a scanning line 31, a signal line 32, and a switching element 33 are formed on the inner surface.
A substrate (not shown) is arranged so as to face the liquid crystal layer 4 in between. In this TFT substrate, scanning lines 31 and signal lines 32 are arranged in a matrix, and a pixel electrode 39 and a switching element 33 are formed for each pixel partitioned by the scanning lines 31 and signal lines 32. . Then, the scanning line 3 of the liquid crystal display element 100
1 and the signal line 32 are driven by the gate driver 34 and the source driver 35, respectively.
And the source driver 35 is controlled by the control circuit 36.

A backlight 200 is provided below the liquid crystal display element 100. This backlight 2
Reference numeral 00 denotes a cold cathode tube or the like that emits white light, and its operation is controlled by the backlight control circuit 37. The operation of the backlight control circuit 37 is controlled by the control circuit 36 like the gate driver 34 and the source driver 35.

Further, the liquid crystal display device according to the present embodiment receives the input of the black insertion rate and outputs the received information indicating the black insertion rate to the control circuit 36 to set the black insertion rate. To the control circuit 36 and the liquid crystal molecules 20.
And a voltage application instructing section 41 for instructing the control circuit 36 to apply a voltage necessary to cause the transition from the splay alignment to the bend alignment.

In the liquid crystal display device according to this embodiment configured as described above, the control circuit 36 controls the gate driver 34, the source driver 35, and the backlight control circuit according to the video signal 38 input from the outside. The control signals are output to 37. As a result, the gate driver 34 applies a scanning signal voltage to the scanning line 31 to sequentially turn on the switching element 33 of each pixel, while the source driver 35 responds to the video signal 38 through the signal line 32 at the timing. The video signal voltage is sequentially applied to the pixel electrode 39 of each pixel. As a result, the liquid crystal molecules 20 are modulated and the transmittance of the light emitted from the backlight 200 changes. As a result, an image corresponding to the video signal 38 appears in the eyes of the observer.

In the black insertion period, the video signal 3
In order to sequentially apply the black display signal voltage corresponding to the black display signal to the pixel electrode 39 of each pixel instead of 8, the control circuit 36 outputs a control signal to the gate driver 34 and the source driver 35, respectively. As a result, black display can be performed during the black insertion period.

Here, when the observer perceives blurring of the image, it is necessary to lengthen the black insertion period in order to eliminate the blurring of the image. On the other hand, when it is perceived that the brightness is low, it is necessary to shorten the black insertion period in order to secure sufficient brightness. In addition, since blurring of an image does not occur when only a still image is displayed, the black insertion period may be shorter than when a moving image is displayed.

Therefore, the observer inputs a desired value of the black insertion rate using the black insertion rate setting unit 40, and controls the control circuit 36 so that the black insertion period has a length according to the input value. Give instructions to. The control circuit 36 receiving this instruction changes the gate driver 34, in order to change the length of the black insertion period.
A control signal is output to each source driver 35. As a result, the black insertion period is changed to the length set by the observer.

Further, when the observer perceives an abnormality in the image display, the voltage application instructing section 41 is used to apply a voltage necessary to cause the liquid crystal molecules 20 to transition from the splay alignment to the bend alignment. Instruct 36. Upon receiving this instruction, the control circuit 36 outputs control signals to the gate driver 34 and the source driver 35, respectively, in order to apply the voltage necessary for the transition to the liquid crystal display element 100. As a result, the voltage is applied to the pixel electrode 39. Accordingly, if the image display abnormality perceived by the observer is caused by the reverse transition of the liquid crystal molecules 20, that is, the alignment state of the liquid crystal molecules 20 is changed from the bend alignment to the splay alignment, the abnormality is resolved. Will be done.

FIG. 4 is a timing chart showing an example of the operation of the liquid crystal display device according to the first embodiment of the present invention. (A) shows the scanning timing for each scanning line 31, (b) shows each signal. The change in the voltage applied to the pixel electrode 39 through the line 32 is shown.

In FIG. 4, N indicates the number of scanning lines 31 included in the liquid crystal display element 100. Also, T1
Is one frame period, and T2 is a video signal voltage for the pixel electrode 3
9 shows a video signal period which is a period applied to 9, and T3 shows a black insertion period.

As shown in FIG. 4, one frame period T1
Is composed of a video signal period T2 and a black insertion period T3. Then, in each of the video signal period T2 and the black insertion period T3, scanning is sequentially performed on all the scanning lines 31 (see FIG. 4A). Further, since the liquid crystal display element 100 is of the dot inversion drive type as described above, the pixel electrodes are so arranged that the voltage polarity of the written signal is inverted dot by dot in each of the video signal period T2 and the black insertion period T3. The voltage applied to 39 changes (see FIG. 4 (b)).

As described above, the viewer inserts the black insertion rate setting unit 4
When a desired black insertion rate is set using 0, the length of the black insertion period T3 changes according to the content of the setting. That is, when the setting is to increase the black insertion rate, the black insertion period T3 becomes longer according to the black insertion rate, and the video signal period T2 becomes shorter accordingly. As a result, it is possible to eliminate the blurring of the image and prevent the liquid crystal molecules 20 from reversely transitioning from the bend alignment to the splay alignment.

On the other hand, when the setting by the observer is to lower the black insertion rate, the black insertion period T3 becomes shorter according to the black insertion rate, and the video signal period T2 becomes longer accordingly. This makes it possible to obtain a good display with high brightness.

In the case of the OCB mode liquid crystal display element, when the black insertion ratio is 0%, that is, when the black insertion period T3 does not exist, the reverse transition from the bend alignment to the splay alignment is likely to occur. Become. Further, even in the case of a liquid crystal display device other than the OCB mode, it is desirable to secure a constant black insertion rate from the viewpoint of image breakage and the like. Furthermore, if the black insertion rate is too high, it becomes impossible to secure the brightness required for obtaining a good display. for that reason,
It is desirable to set a range that can be set using the black insertion rate setting unit 40 in advance so as to prevent an inappropriate black insertion rate from being set due to an error by an observer. The range that can be set here is, for example, about 5% or more and 75% or less so that the reverse transition is unlikely to occur and appropriate brightness can be secured.

The liquid crystal display device according to the present embodiment is constructed so that the black insertion rate can be set according to the preference of the observer, but not the observer, for example, the manufacturer side. Only the black insertion rate setting unit 40 may be used to set the black insertion rate. In the case of such a configuration, there are variations in the manufacturing process of the liquid crystal display element 100, for example, and as a result, the liquid crystal molecules 20
Even when the bend alignment state of the liquid crystal display device 100 is different for each liquid crystal display element 100, the black insertion rate setting unit is configured to display at an appropriate black insertion rate according to each liquid crystal display element 100 on the manufacturer side. The liquid crystal display device according to the present embodiment can be shipped after the setting is performed using 40.

(Second Embodiment) In the liquid crystal display device according to the second embodiment, in order to facilitate the setting of the black insertion rate, a plurality of modes relating to the black insertion rate are prepared in advance,
The observer can select a specific mode from those modes.

FIG. 5 is a block diagram showing the structure of the liquid crystal display device according to the second embodiment of the present invention. As shown in FIG. 5, the liquid crystal display device according to the present embodiment includes a control circuit 5
0, and the control circuit 50 includes a ROM 51 having a predetermined storage area. This ROM51
Is information indicating the black insertion rate (hereinafter referred to as black insertion rate information)
Are stored, and each black insertion rate information indicates a different black insertion rate.

Further, the liquid crystal display device according to the present embodiment is equipped with a mode setting section 52 used for setting the mode relating to the black insertion rate.
Are connected to the control circuit 50.

Since the other structure of the liquid crystal display device according to the present embodiment is the same as that of the first embodiment, the same reference numerals are given and the description thereof is omitted.

An observer who observes the liquid crystal display device according to the present embodiment configured as described above inputs a mode relating to a desired black insertion rate using the mode setting section 52 described above. The mode setting unit 52 that has received the input of this mode
Outputs a signal indicating the accepted mode to the control circuit 50. The control circuit 50, which receives the signal output from the mode setting unit 52, changes the RO according to the received signal.
One piece of black insertion rate information is selected from the plurality of pieces of black insertion rate information stored in M51. Then, in order to realize the black insertion rate indicated by the selected black insertion rate information, control signals are output to the gate driver 34 and the source driver 35, respectively. As a result, the display is performed according to the black insertion rate mode set by the observer.

As described above, the observer can easily set a desired black insertion rate by operating the mode setting section 52. Therefore, for example, when displaying a large number of moving images, it is possible to easily prevent image blurring by setting the mode with a high black insertion rate.

As described above, in this embodiment, the control circuit 50 stores the predetermined black insertion rate information in the ROM 5
However, the black insertion rate information can be changed, added, or erased by an observer's operation by making the ROM 51 a rewritable memory such as an EEPROM. Such a configuration may be adopted. With such a configuration, the observer can create a desired mode.

(Third Embodiment) The liquid crystal display device according to the third embodiment is constructed so that the black insertion rate can be set according to the temperature in the vicinity of the liquid crystal display element.

FIG. 6 is a block diagram showing the structure of the liquid crystal display device according to the third embodiment of the present invention. As shown in FIG. 6, the liquid crystal display device according to the present embodiment includes a temperature sensor 60 for measuring the temperature near the surface of the liquid crystal display element 100. The temperature sensor 60 is a control circuit 36.
It is connected to the.

The rest of the configuration of the liquid crystal display device according to the present embodiment is the same as that of the first embodiment, so the same reference numerals are given and the description thereof is omitted.

In the liquid crystal display device according to the present embodiment configured as described above, the temperature sensor 60 constantly measures the temperature near the surface of the liquid crystal display element 100, and information indicating the measurement result (hereinafter, The temperature information) is output to the control circuit 36 at predetermined time intervals. Note that the temperature sensor may not always measure as described above, but the temperature may be measured only within a specific time according to an instruction from the observer.

Further, the control circuit 36 having received the temperature information output from the temperature sensor 60 determines the black insertion rate based on the received temperature information and the graph as shown in FIG.

FIG. 7 is a graph showing the relationship between the temperature near the surface of the liquid crystal display element 100 and the appropriate black insertion rate. As described above, when the liquid crystal display device is used at a high temperature, the liquid crystal molecules are easily moved, so that the reverse transition from the bend alignment to the splay alignment is likely to occur. The inventors of the present invention, in order to specify the black insertion rate that can prevent the reverse transition and stably maintain the bend alignment, the temperature near the surface of the liquid crystal display element and an appropriate black insertion rate I investigated the relationship. Specifically, it is necessary to display an image while changing the temperature near the surface of the liquid crystal display element and the black insertion rate, to stably maintain the bend alignment state, and to obtain a good display. The relationship between the temperature and the black insertion rate at which the brightness can be secured was obtained by subjective evaluation. Points A1 to A6 in FIG. 7 show the relationship between the temperature and the black insertion rate thus obtained.

As described above, the control circuit 36 determines the black insertion rate based on the temperature information output from the temperature sensor 60 and the graph shown in FIG. 7, that is, the curve A connecting the points A1 to A6. decide. For example, when the temperature information is about 20 ° C., the black insertion rate is determined to be 15%, and control signals are output to the gate driver 34 and the source driver 35 to realize the black insertion rate. As a result, good display can be maintained regardless of whether the liquid crystal display device according to the present embodiment is used under high temperature or low temperature.

(Embodiment 4) The liquid crystal display device according to Embodiment 1 realizes color display by using color filters. On the other hand, the liquid crystal display device according to the fourth embodiment realizes color display by the field sequential color system.

Therefore, the liquid crystal display device according to the present embodiment is provided with a backlight having a light source that emits light of each of the three primary colors of light, red, green and blue. Similarly, the liquid crystal display device includes a backlight control circuit that controls the above-described backlight so as to emit red, green, and blue color lights in a time-division manner within one field period. Note that the other configurations are the same as those of the first embodiment.
The description is omitted because it is the same as the case.

Next, the operation of the liquid crystal display device according to this embodiment will be described.

FIG. 8 is a timing chart showing an example of the operation of the liquid crystal display device according to the fourth embodiment of the present invention. FIG. 8A shows the scanning timing for each scanning line.
(B) shows changes in the video signal voltage applied to the pixel electrodes via the respective signal lines.

In FIG. 8, TR is a red sub-frame period during which the backlight emits red light, TG is a green sub-frame period during which green light is emitted, and TB is also blue light. The blue sub-frame periods, which are the periods for emitting light, are shown.

As shown in FIG. 8, one frame period T1
Are sub-frame periods TR, TG, TB of each of these colors.
And a black insertion period T3. Then, in each of the sub-frame periods TR, TG, TB and the black insertion period T3, scanning is sequentially performed on all scanning lines (see FIG. 8A). Further, as in the case of the first embodiment, since the liquid crystal display element included in the liquid crystal display device according to the present embodiment is the dot inversion drive, the sub-frame periods TR, TG, TB of each color and the black insertion period T3 are set. In each of the above, the voltage applied to the pixel electrode changes so that the voltage polarity of the written signal is inverted for each dot (see FIG. 8B).

Also in the liquid crystal display device according to the present embodiment, the observer can set a desired black insertion rate using the black insertion rate setting unit, as in the case of the first embodiment. Then, when such a setting is made, the length of the black insertion period T3 changes according to the contents of the setting. As a result, it is possible to display at a black insertion rate according to the preference of the observer.

In this embodiment, there is only one black insertion period T3 within one frame period T1 as shown in FIG. 8, but a plurality of black insertion periods T3 within one frame period T1.
May be provided. That is, for example, the black insertion period T3 may be provided after the sub-frame periods TR, TG, and TB of each color.

As in the case of the second embodiment, the black insertion rate information is stored in advance and the black insertion rate is changed according to the mode relating to the black insertion rate set by the observer. It may be. Further, as in the case of the third embodiment, a temperature sensor that measures the temperature near the surface of the liquid crystal display element may be provided, and the black insertion rate may be changed to an appropriate black insertion rate according to the temperature.

[0078]

As described above in detail, according to the liquid crystal display device of the present invention, it is possible to change the ratio of the non-video signal period within one frame period, so that the ratio can be used and the operating environment. It is possible to maintain a good display by setting an appropriate value according to the above.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a configuration of a liquid crystal display element included in a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically showing an alignment state of liquid crystal molecules included in a liquid crystal display element.

FIG. 3 is a block diagram showing the configuration of the liquid crystal display device according to the first embodiment of the present invention.

FIG. 4 is a timing chart showing an example of the operation of the liquid crystal display device according to the first embodiment of the present invention, in which (a) shows scanning timing for each scanning line and (b) shows each signal line. Changes in the video signal voltage applied to the pixel electrode 39 are shown.

FIG. 5 is a block diagram showing a configuration of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a liquid crystal display device according to a third embodiment of the present invention.

FIG. 7 is a graph showing the relationship between the temperature near the surface of the liquid crystal display element and an appropriate black insertion rate.

FIG. 8 is a timing chart showing an example of the operation of the liquid crystal display device according to the fourth embodiment of the present invention, in which (a) shows the scanning timing for each scanning line and (b) shows each signal line. The change of the video signal voltage applied to the pixel electrode is shown.

[Explanation of symbols]

1 glass substrate 2 transparent electrode 3 Alignment film 4 Liquid crystal layer 5 dura 6 transparent electrodes 7 glass substrate 8,9 Retardation film 10, 11 Polarizing plate 20 liquid crystal molecules 31 scan lines 32 signal lines 33 switching elements 34 Gate driver 35 Source Driver 36 Control circuit 37 Backlight control circuit 38 video signals 39 pixel electrodes 40 Black insertion rate setting section 41 Voltage application instruction section 50 control circuit 51 ROM 52 Mode setting section 60 temperature sensor 100 liquid crystal display element 101 upper substrate 102 lower substrate 200 backlight T1 1 frame period T2 video signal period T3 black insertion period

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09G 3/20 631 G09G 3/20 631V 642 642P 660 660V 3/34 3/34 J 3/36 3/36 (72) Inventor Tetsuo Fukaumi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. HA12 HA16 HA28 JA05 JA11 MA20 2H093 NA16 NA31 NA41 NC34 NC43 NC47 NC57 ND10 ND60 NE01 NF05 5C006 AC24 AF44 AF52 AF54 AF59 AF62 AF78 BA15 BB16 BB29 BC03 BC11 BC16 BF01 BF38 EA01 FA19 FA20 FA29 GA01 5C080 ADD09BB05 CC11 AJ09BB05 CC0803DD12 BB01

Claims (8)

[Claims] 1. A liquid crystal display element having a plurality of pixel electrodes arranged in a matrix and a plurality of switching elements provided corresponding to the pixel electrodes, respectively, and externally input in one frame period. A video signal and a non-video signal different from the video signal are supplied to the pixel electrodes by driving the switching elements, respectively.
In a liquid crystal display device that performs display according to the video signal and the non-video signal using the liquid crystal display element, a non-video signal period for supplying the non-video signal to the pixel electrode occupies within one frame period. A liquid crystal display device comprising an adjusting means for adjusting a ratio. 2. The liquid crystal display device according to claim 1, wherein the liquid crystal display element has liquid crystal molecules that are in bend alignment when the display is performed. 3. An illuminating device having light sources for emitting red, green, and blue color lights respectively, and controlling the illuminating device so that the light sources emit each color light in a time-division manner within one frame period. The liquid crystal display device according to claim 1, further comprising illumination device control means. 4. The receiving device further comprises an accepting unit that accepts input of ratio information indicating the ratio, and the adjusting unit is configured to adjust the ratio based on the ratio information input by the accepting unit. The liquid crystal display device according to claim 1. 5. The adjusting means further comprises storage means for storing a plurality of ratio information indicating the ratio, and selection means for selecting specific ratio information from the ratio information stored by the storage means. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is configured to adjust the ratio based on the ratio information selected by the selection unit. 6. A temperature sensor for measuring the temperature in the vicinity of the liquid crystal display element is further provided, and the adjusting means is configured to adjust the ratio based on a measurement result of the temperature sensor.
The liquid crystal display device according to item 1. 7. The adjusting means adjusts the ratio to 5% or more 7
The liquid crystal display device according to claim 1, wherein the liquid crystal display device is configured to be adjusted within a range of 5% or less. 8. An applying means for applying a voltage to the liquid crystal display element for causing the liquid crystal molecules to transition from a splay alignment to a bend alignment, and instructing the applying means to apply the voltage to the liquid crystal display element. The liquid crystal display device according to claim 2, further comprising: an instruction unit used for performing the operation.