JP2013258588A - Stereoscopic display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost stereoscopic display device which makes it difficult for a user to recognize crosstalk.SOLUTION: In the stereoscopic display device which is provided with a back light shutting off corner to corner and lighting on corner to corner and updates a screen from the top end toward the bottom end in order, when a character is displayed in the lower section of the screen, a control signal CB of the backlight and a control signal CX of shutter eyeglasses are delayed by a predetermined period td. When a character is displayed in the upper section of the screen, the control signals CB and CX are delayed by the period td and the screen is updated in order from the bottom end toward the upper end. In accordance with the feature of an image to be displayed on the screen, the relative relation between an image display timing and the control timing of the backlight and the shutter eyeglasses is switched to make it difficult to recognize the crosstalk.

Description

  The present invention relates to a stereoscopic display device, and more particularly to a shutter glasses type stereoscopic display device.

  2. Description of the Related Art Conventionally, various 3D display devices that display an image in 3D are known. A shutter glasses type stereoscopic display device that displays a screen on a liquid crystal panel will be described below. In a shutter glasses type stereoscopic display device, a left-eye image and a right-eye image are alternately displayed on the screen, and a user wears glasses having a left-eye shutter and a right-eye shutter (hereinafter referred to as shutter glasses) to view the screen. . The shutter glasses are controlled so that the left-eye shutter is opened while the left-eye image is displayed, and the right-eye shutter is opened while the right-eye image is displayed. Thereby, the user recognizes the stereoscopic image.

  In a shutter glasses type stereoscopic display device, a phenomenon in which a left-eye image and a right-eye image are displayed together (referred to as crosstalk) may occur and display quality may deteriorate. In order to reduce crosstalk, it is necessary to perform image display and control of the backlight and shutter glasses at suitable timing.

  Patent Document 1 describes a stereoscopic display device that reduces crosstalk by dividing a screen into a plurality of areas and using a backlight that can control lighting and extinction for each area. This stereoscopic display device has a problem that the cost increases because the backlight is controlled for each region. In order to reduce the cost of the stereoscopic display device, it is preferable to use a backlight that is turned on and off.

JP 2010-276828 A

  However, it is difficult to make the crosstalk constant in the entire screen in a stereoscopic display device using a backlight that is turned on and off. FIG. 13 is a diagram illustrating an example of a change in the transmittance of a pixel in the stereoscopic display device. When the screen is updated in order from the top to the bottom, the transmittance of the pixel at the center of the screen changes later than the transmittance of the pixel at the top of the screen, and the transmittance of the pixel at the bottom of the screen is greater than the pixel at the center of the screen. Changes with a delay. The backlight is turned on in the period T1.

  In the conventional stereoscopic display device, the timing for displaying an image and the timing for controlling the backlight and the shutter glasses are fixedly determined so that the crosstalk is reduced at the center of the screen. For this reason, the crosstalk is reduced in the central portion of the screen, but a larger crosstalk occurs in the upper and lower portions of the screen than in the central portion of the screen.

  In FIG. 13, the transmittance of the pixels at the top of the screen starts to change within the backlight lighting period T1. As described above, since the transmittance of the pixels starts to change before the backlight is turned off, the image of the next frame is mixed with the image of the current frame at the top of the screen, and crosstalk occurs. On the other hand, the transmittance of the pixel at the bottom of the screen has not yet reached the final value at the start of the backlight lighting period T1. As described above, since the backlight is turned on before the pixel transmittance reaches the final value, the image of the previous frame is mixed with the image of the current frame at the bottom of the screen, and crosstalk occurs.

  The deterioration of display quality due to crosstalk becomes noticeable when characters are displayed on the screen. In general, movie subtitles are displayed at the bottom of the screen, and data broadcasting displays text at the top of the screen. For this reason, when various timings are determined so that crosstalk is reduced in the center of the screen, the visibility of movie subtitles displayed at the bottom of the screen and text of data broadcasts displayed at the top of the screen is reduced.

  Therefore, an object of the present invention is to provide a low-cost stereoscopic display device in which a user is difficult to recognize crosstalk.

A first invention is a shutter glasses type stereoscopic display device,
A liquid crystal panel that displays a screen;
A panel driving circuit for sequentially updating the screen from the first end toward the second end according to a first control signal, and alternately displaying a left-eye image and a right-eye image on the screen;
A backlight provided on the back side of the liquid crystal panel, which is turned on and turned off in accordance with a second control signal;
Shutter glasses having a left-eye shutter and a right-eye shutter alternately opened according to a third control signal;
A control signal generator for generating the first, second and third control signals;
A timing adjustment unit that switches a relative timing of the second and third control signals with respect to the first control signal in accordance with a feature of the video displayed on the screen.

According to a second invention, in the first invention,
The timing adjustment unit switches a relative timing of the second and third control signals with respect to the first control signal according to a position of a character displayed on the screen.

According to a third invention, in the second invention,
When a character is displayed at a position closer to the second end than the first end in the screen, the timing adjustment unit delays the second and third control signals generated by the control signal generation unit It is characterized by that.

According to a fourth invention, in the third invention,
When a character is displayed at a position closer to the first end than the second end in the screen, the timing adjustment unit delays the second and third control signals generated by the control signal generation unit. The panel driving circuit updates the screen in order from the second end toward the first end.

According to a fifth invention, in the third invention,
When a character is displayed at a position closer to the first end than the second end in the screen, the timing adjustment unit delays the first control signal generated by the control signal generation unit. And

A sixth invention is the second invention, wherein:
The control signal generation unit outputs the first, second, and third control signals according to a timing at which the left-eye image and the right-eye image are displayed separately in a central portion of the screen. To do.

According to a seventh invention, in the second invention,
A video determination unit that outputs a determination signal indicating the position of the character displayed on the screen based on the input video signal;
The timing adjustment unit switches a relative timing of the second and third control signals with respect to the first control signal according to the determination signal.

In an eighth aspect based on the second aspect,
The timing adjustment unit switches relative timings of the second and third control signals with respect to the first control signal in accordance with a determination signal that is supplied from outside and indicates a position of a character displayed on the screen. It is characterized by that.

According to a ninth invention, in the second invention,
The first end is an upper end of the screen, and the second end is a lower end of the screen.

According to a tenth aspect of the present invention, there is provided a liquid crystal panel for displaying a screen, the screen is sequentially updated from the first end toward the second end in accordance with a first control signal, and a left eye image and a right eye image are alternately displayed on the screen. A panel driving circuit to be operated, a backlight which is provided on the back side of the liquid crystal panel and which is turned on and off in accordance with the second control signal, and a left eye shutter and a right eye shutter which are alternately opened in accordance with the third control signal. A stereoscopic display device driving method including shutter glasses having,
Generating the first, second and third control signals;
Switching relative timings of the second and third control signals with respect to the first control signal according to the characteristics of the video displayed on the screen.

  According to the first or tenth aspect, the relative relationship between the timing for displaying an image and the timing for controlling the backlight and the shutter glasses is switched according to the characteristics of the video. Therefore, it is possible to make it difficult to recognize the crosstalk by switching the portion where the crosstalk is reduced in the screen according to the feature of the video. Further, the cost of the stereoscopic display device can be reduced by using a backlight that is turned on and off.

  According to the second aspect, the relative relationship between the timing for displaying an image and the timing for controlling the backlight and the shutter glasses is switched according to the display position of the character. Therefore, it is possible to make it difficult to recognize the crosstalk by switching the portion where the crosstalk is reduced in the screen according to the display position of the character.

  According to the third aspect of the present invention, when characters are displayed in a portion that is updated in the latter half of the screen, the timing for controlling the backlight and shutter glasses is delayed, thereby reducing crosstalk at the character display position. In addition, it is possible to make it difficult to recognize crosstalk.

  According to the fourth aspect of the invention, when characters are displayed in the first half of the screen, the timing for controlling the backlight and shutter glasses is delayed and the screen is updated in the reverse order. The crosstalk can be reduced at the character display position, making it difficult to recognize the crosstalk.

  According to the fifth aspect, when a character is displayed in a portion that is updated in the first half of the screen, the crosstalk is reduced at the character display position by delaying the timing for displaying the image, and the crosstalk is displayed. Can be difficult to recognize.

  According to the sixth aspect, the crosstalk can be reduced at the center of the screen by controlling the image display and the backlight and the shutter glasses using the control signal generated by the control signal generator. .

  According to the seventh aspect of the invention, the determination signal indicating the character display position is generated inside the stereoscopic display device, and this is used to switch the portion where the crosstalk is reduced on the screen, thereby making it difficult to recognize the crosstalk. can do.

  According to the eighth aspect of the invention, it is difficult to recognize the crosstalk by switching the portion where the crosstalk is reduced in the screen by using the determination signal indicating the character display position supplied from the outside of the stereoscopic display device. be able to.

  According to the ninth aspect, in the stereoscopic display device that sequentially updates the screen from the upper end toward the lower end, the portion where the crosstalk is reduced in the screen is switched according to the character display position to recognize the crosstalk. Can be difficult.

1 is a block diagram illustrating a configuration of a stereoscopic display device according to a first embodiment of the present invention. It is a block diagram which shows the detail of the display control part contained in the three-dimensional display apparatus shown in FIG. It is a figure which shows the example of the change of the transmittance | permeability of the pixel in normal mode about the three-dimensional display apparatus shown in FIG. It is a figure which shows the example of the change of the transmittance | permeability of the pixel in movie mode about the three-dimensional display apparatus shown in FIG. It is a block diagram which shows the detail of the display control part contained in the three-dimensional display apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the example of the change of the transmittance | permeability of the pixel in data broadcast mode about the three-dimensional display apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the three-dimensional display apparatus which concerns on the 3rd Embodiment of this invention. FIG. 8 is a block diagram illustrating details of a display control unit included in the stereoscopic display device illustrated in FIG. 7. It is a figure which shows the example of the change of the transmittance | permeability of the pixel in a data broadcast mode about the three-dimensional display apparatus shown in FIG. It is a block diagram which shows the detail of the display control part contained in the three-dimensional display apparatus which concerns on the 1st modification of this invention. It is a block diagram which shows the detail of the display control part contained in the three-dimensional display apparatus which concerns on the 2nd modification of this invention. It is a block diagram which shows the detail of the display control part contained in the three-dimensional display apparatus which concerns on the 3rd modification of this invention. It is a figure which shows the example of the change of the transmittance | permeability of the pixel in the conventional stereoscopic display apparatus.

(First embodiment)
FIG. 1 is a block diagram showing a configuration of a stereoscopic display device according to the first embodiment of the present invention. A stereoscopic display device 10 shown in FIG. 1 includes a liquid crystal panel 1, a scanning signal line driving circuit 2, a video signal line driving circuit 3, a backlight 4, shutter glasses 5, and a display control unit 11. The stereoscopic display device 10 performs shutter glasses type stereoscopic display.

  The liquid crystal panel 1 is a display panel that displays a screen. The liquid crystal panel 1 includes m scanning signal lines G1 to Gm, n video signal lines S1 to Sn, and (m × n) pixels P (where m and n are two or more). integer). The scanning signal lines G1 to Gm are arranged in parallel to each other. The video signal lines S1 to Sn are arranged in parallel to each other so as to be orthogonal to the scanning signal lines G1 to Gm. The pixel P is disposed corresponding to each of the intersections of the scanning signal lines G1 to Gm and the video signal lines S1 to Sn, and is connected to the corresponding scanning signal line and the corresponding video signal line.

  The display control unit 11 controls the operation of the stereoscopic display device 10. A horizontal synchronization signal HSYNC, a vertical synchronization signal VSYNC, a left / right switching signal LR, and a video signal D1 are input to the display control unit 11 from the outside of the stereoscopic display device 10. Based on these signals, the display control unit 11 outputs a control signal CG to the scanning signal line driving circuit 2, outputs a control signal CS and a video signal D2 to the video signal line driving circuit 3, and a backlight. 4 outputs a control signal CB, and outputs a control signal CX to the shutter glasses 5.

  The scanning signal line driving circuit 2 and the video signal line driving circuit 3 are driving circuits for the liquid crystal panel 1. The scanning signal line driving circuit 2 sequentially drives the scanning signal lines G1 to Gm based on the control signal CG. More specifically, the control signal CG supplied to the scanning signal line drive circuit 2 includes a gate start pulse and a gate clock. Based on these control signals, the scanning signal line drive circuit 2 selects the scanning signal lines G1 to Gm in ascending order (in the order of G1, G2,..., Gm). In the selection period of the scanning signal line Gi (i is an integer of 1 to m), n pixels P connected to the scanning signal line Gi are selected at once.

  The video signal line driving circuit 3 drives the video signal lines S1 to Sn based on the control signal CS and the video signal D2. More specifically, the control signal CS supplied to the video signal line driving circuit 3 includes a source start pulse, a source clock, and the like. The video signal line drive circuit 3 generates n gray scale voltages according to n video data included in the video signal D2, and applies the generated n gray scale voltages to the video signal lines S1 to Sn, respectively. To do. As a result, n gray scale voltages are respectively written in the n pixels P selected using the scanning signal line driving circuit 2. By performing the process of writing n gradation voltages m times, a desired image can be displayed on the liquid crystal panel 1.

  Hereinafter, the scanning signal line G1 side of the liquid crystal panel 1 corresponds to the upper end of the screen, and the scanning signal line Gm side corresponds to the lower end of the screen. Since the scanning signal lines G1 to Gm are selected in ascending order, the screen is updated in order from the upper end to the lower end.

  The backlight 4 is provided on the back side of the liquid crystal panel 1 and irradiates the back of the liquid crystal panel 1 with light. The backlight 4 is turned on and turned off in accordance with the control signal CB. For example, the backlight 4 is turned on when the control signal CB is at a high level, and is turned off when the control signal CB is at a low level.

  The shutter glasses 5 include a left-eye shutter 6L and a right-eye shutter 6R that are configured by liquid crystal shutters. The shutter glasses 5 switch which of the left-eye shutter 6L and the right-eye shutter 6R is opened according to the control signal CX. For example, when the control signal CX is at a low level, the left eye shutter 6L is in an open state, and when the control signal CX is at a high level, the right eye shutter 6R is in an open state.

  The video signal D1 includes left-eye signals and right-eye signals alternately in image units. The left / right switching signal LR indicates whether the video signal D1 is a left-eye signal or a right-eye signal. The video signal line drive circuit 3 drives the video signal lines S1 to Sn by using the left-eye signal and the right-eye signal alternately for each image. Therefore, the left-eye image and the right-eye image are alternately displayed on the screen. The user wears the shutter glasses 5 and sees the screen. The shutter glasses 5 are configured such that the left-eye shutter 6L is opened while the left-eye image is displayed on the screen, and the right-eye shutter 6R is opened while the right-eye image is displayed on the screen. Be controlled. Thereby, the user recognizes the stereoscopic image.

  FIG. 2 is a block diagram showing details of the display control unit 11. The display control unit 11 illustrated in FIG. 2 includes a control signal generation unit 12, a video determination unit 13, a timing adjustment unit 14, and a buffer memory 15.

  The control signal generator 12 receives a horizontal synchronization signal HSYNC, a vertical synchronization signal VSYNC, and a left / right switching signal LR. The control signal generation unit 12 generates control signals cg, cs, cb, cx based on these control signals. The control signal generation unit 12 outputs the control signals cg, cs, cb, and cx according to the timing at which crosstalk becomes small at the center of the screen (the left-eye image and the right-eye image are displayed separately at the center of the screen). To do. The control signals cg and cs are supplied to the scanning signal line drive circuit 2 and the video signal line drive circuit 3 as control signals CG and CS, respectively.

  Based on the video signal D1, the video determination unit 13 outputs a determination signal Q1 indicating the position of the character displayed on the screen as a feature of the video displayed on the screen. More specifically, the video determination unit 13 outputs a determination signal Q1 having a value 1 when the video displayed on the screen is “a movie including subtitles at the bottom of the screen”, and has a value 0 otherwise. The signal Q1 is output. In the present embodiment, when the value of the determination signal Q1 is 1, it is called a movie mode, and when the value of the determination signal Q1 is 0, it is called a normal mode.

  The timing adjustment unit 14 includes delay circuits 16c and 16d and switch circuits 17c and 17d. The delay circuits 16c and 16d delay the control signals cb and cx by a predetermined time td, respectively. For example, the time td is set to a required time for updating 1/3 of the screen. The switch circuit 17c selects the output signal of the delay circuit 16c in the movie mode, and selects the control signal cb in the normal mode. The switch circuit 17d selects the output signal of the delay circuit 16d in the movie mode, and selects the control signal cx in the normal mode. Output signals of the switch circuits 17c and 17d are supplied to the backlight 4 and the shutter glasses 5 as control signals CB and CX, respectively.

  The timing adjustment unit 14 outputs control signals cb and cx as control signals CB and CX in the normal mode, and outputs signals obtained by delaying the control signals cb and cx by time td as the control signals CB and CX in the movie mode. Therefore, the control signals CB and CX are delayed by the time td in the movie mode than in the normal mode. In this way, the timing adjustment unit 14 switches the relative timing of the control signals CB and CX with respect to the control signals CG and CS.

  The buffer memory 15 temporarily stores the video signal D1, and outputs the stored video signal in accordance with the timing of the control signals CG and CS. The output signal of the buffer memory 15 is supplied to the video signal line drive circuit 3 as the video signal D2.

  Hereinafter, effects of the stereoscopic display device 10 will be described. 3 and 4 are diagrams illustrating examples of changes in pixel transmittance (pixel luminance) in the stereoscopic display device 10. FIG. 3 shows changes in pixel transmittance in the normal mode, and FIG. 4 shows changes in pixel transmittance in the movie mode. In the following description, when the screen is divided into three in the vertical direction, three pixels included in the upper part of the screen, the central part of the screen, and the lower part of the screen are considered. When the length in the vertical direction of the screen is L, the pixel at the top of the screen and the pixel at the center of the screen are separated by (L / 3) in the vertical direction of the screen, and the pixel at the center of the screen and the pixel at the bottom of the screen are Assume that the screen is separated by (L / 3) in the vertical direction.

  In the normal mode (FIG. 3), the transmittance of the pixels at the top of the screen starts to change at time ta. The transmittance of the pixel at the center of the screen changes with a delay of time td from the transmittance of the pixel at the top of the screen. The transmittance of the pixel at the bottom of the screen changes with a delay of time td from the transmittance of the pixel at the center of the screen. Even in the movie mode (FIG. 4), the transmittance of each pixel changes at the same timing as in the normal mode.

  In the normal mode, the control signal CB (not shown) is at a high level during the period T1 starting from the time tb, and the backlight 4 is turned on entirely during the period T1. The period T1 starts near the time when the transmittance of the pixels in the center of the screen reaches the final value, and ends at the time when the transmittance of the pixels in the center of the screen starts to change. The control signal CX changes from the high level to the low level (or from the low level to the high level) around the time when the period T1 ends.

  The control signals CB and CX are delayed by a time td in the movie mode than in the normal mode. In the movie mode, the control signal CB (not shown) is at a high level during a period T2 starting from time (tb + td), and the backlight 4 is turned on entirely during the period T2. The period T2 starts near the time when the transmittance of the pixel at the bottom of the screen reaches the final value, and ends near the time when the transmittance of the pixel at the bottom of the screen starts to change. The control signal CX changes near the time when the period T2 ends.

  The timings of the control signals cg, cs, cb, cx are determined so that the crosstalk becomes small at the center of the screen. In the normal mode, the control signals cg, cs, cb, cx are used as they are (without delay) as the control signals CG, CS, CB, CX, so that the crosstalk is reduced at the center of the screen. On the other hand, in the movie mode, the control signals CB and CX are delayed by the time td from the normal mode, so that the crosstalk is reduced at the lower part of the screen.

  As described with reference to FIG. 13, in the conventional stereoscopic display device, the timing for displaying an image and the timing for controlling the backlight and the shutter glasses are fixedly determined so that the crosstalk is reduced at the center of the screen. Is done. For this reason, a larger crosstalk occurs in the lower part of the screen than in the central part of the screen, and the visibility of the subtitles of the movie displayed in the lower part of the screen decreases.

  In the stereoscopic display device 10, the crosstalk is reduced at the center of the screen in the normal mode, and the crosstalk is reduced at the bottom of the screen in the movie mode. For this reason, in the movie mode, the crosstalk becomes larger at the upper part of the screen and at the center part of the screen than before, but the crosstalk becomes smaller at the lower part of the screen than before. When the video displayed on the screen is “movie including subtitles at the bottom of the screen”, the user pays attention to the bottom of the screen where the subtitles are displayed. Therefore, in the movie mode, by delaying the control signals CB and CX by the time td compared to the normal mode, the crosstalk can be reduced at the lower part of the screen, and the visibility of the subtitles of the movie displayed at the lower part of the screen can be improved. In addition, the stereoscopic display device 10 includes a backlight 4 that is turned on and turned off. Therefore, the cost can be reduced as compared with a stereoscopic display device including a backlight that can be turned on and off for each region.

  As described above, the stereoscopic display device 10 according to the present embodiment moves the screen from the first end toward the second end according to the liquid crystal panel 1 that displays the screen and the first control signals (control signals CG and CS). A panel driving circuit (scanning signal line driving circuit 2 and video signal line driving circuit 3) that sequentially updates (from the upper end to the lower end) and alternately displays a left-eye image and a right-eye image on the screen; Provided on the back side, the backlight 4 is turned on and off in accordance with the second control signal (control signal CB), and the left-eye shutter 6L and the right-eye are alternately opened in accordance with the third control signal (control signal CX). Based on the shutter glasses 5 having the shutter 6R, the control signal generator 12 that generates the first to third control signals (control signals cg, cs, cb, cx), and the input video signal D1, A video determination unit 13 that outputs a determination signal Q1 indicating the characteristic (character position) of the displayed video, and the second and the second control signals for the first control signal according to the characteristic (character position) of the video displayed on the screen. And a timing adjustment unit 14 that switches the relative timing of the third control signal (the relative timing of the control signals CB and CX with respect to the control signals CG and CS).

  In the stereoscopic display device 10, the relative relationship between the timing for displaying an image and the timing for controlling the backlight 4 and the shutter glasses 5 is switched according to the characteristics of the video (character display position). Therefore, it is possible to make it difficult to recognize the crosstalk by switching the portion where the crosstalk is reduced in the screen according to the feature of the video (character display position). Moreover, the cost of the stereoscopic display device 10 can be reduced by using the backlight 4 that is turned on and off.

  In addition, the control signal generation unit 12 outputs the first to third control signals (control signals cg, cs, cb, cx) at the timing when the left-eye image and the right-eye image are displayed separately in the center of the screen. To do. Therefore, by controlling the image display and the backlight 4 and the shutter glasses 5 using the control signal generated by the control signal generation unit 12, the crosstalk can be reduced at the center of the screen. The timing adjustment unit 14 also generates the second and third control signals generated by the control signal generation unit 12 when a character is displayed at a position closer to the second end than the first end (lower part of the screen) in the screen. (Control signals cb, cx) are delayed. When characters are displayed in the second half of the screen (lower part of the screen), the crosstalk is reduced at the character display position by slowing the timing of controlling the backlight 4 and the shutter glasses 5, thereby reducing the crosstalk. Talk can be made difficult to recognize.

(Second Embodiment)
The stereoscopic display device according to the second embodiment of the present invention has the same configuration as the stereoscopic display device according to the first embodiment (see FIG. 1). The stereoscopic display device according to the present embodiment includes a display control unit 21 illustrated in FIG. 5 instead of the display control unit 11. Among the constituent elements of the present embodiment, the same elements as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  FIG. 5 is a block diagram showing details of the display control unit 21. The display control unit 21 illustrated in FIG. 5 includes a control signal generation unit 12, a video determination unit 23, a timing adjustment unit 24, and a buffer memory 25.

  Based on the video signal D1, the video determination unit 23 outputs a determination signal Q2 indicating the position of the character displayed on the screen as a feature of the video displayed on the screen. More specifically, the video determination unit 23 outputs a determination signal Q2 having a value of 1 when the video displayed on the screen is “movie including subtitles at the bottom of the screen”, and the video displays “text at the top of the screen”. In the case of “including data broadcasting”, a determination signal Q2 having a value of 2 is output, and in other cases, a determination signal Q2 having a value of 0 is output. In the present embodiment and the third embodiment, when the value of the determination signal Q1 is 1, it is referred to as a movie mode, when the value of the determination signal Q1 is 2 is referred to as a data broadcast mode, and when not, it is referred to as a normal mode.

  The timing adjustment unit 24 includes delay circuits 16a to 16d and switch circuits 27a to 27d. The delay circuits 16a to 16d delay the control signals cg, cs, cb, and cx by time td, respectively. The switch circuit 27a selects the output signal of the delay circuit 16a when the value of the determination signal Q2 is 2, and selects the control signal cg otherwise. The switch circuit 27b selects the output signal of the delay circuit 16b when the value of the determination signal Q2 is 2, and otherwise selects the control signal cs. The switch circuit 27c selects the output signal of the delay circuit 16c when the value of the determination signal Q2 is 1, and selects the control signal cb otherwise. The switch circuit 27d selects the output signal of the delay circuit 16d when the value of the determination signal Q2 is 1, and selects the control signal cx otherwise. Output signals of the switch circuits 27a to 27d are supplied to the scanning signal line drive circuit 2, the video signal line drive circuit 3, the backlight 4, and the shutter glasses 5 as control signals CG, CS, CB, and CX, respectively. .

  The timing adjustment unit 24 outputs control signals cg, cs, cb, and cx as control signals CG, CS, CB, and CX in the normal mode, and controls signals obtained by delaying the control signals cb and cx by time td in the movie mode. Signals CB and CX are output. In the data broadcasting mode, signals obtained by delaying control signals cg and cs by time td are output as control signals CG and CS. Therefore, the control signals CB and CX are delayed by the time td in the movie mode from the normal mode, and the control signals CG and CS are delayed by the time td in the data broadcast mode from the normal mode. In this way, the timing adjustment unit 24 switches the relative timing of the control signals CB and CX with respect to the control signals CG and CS.

  The buffer memory 25 temporarily stores the video signal D1, and outputs the stored video signal in accordance with the timings of CG and CS. Since the control signals CG and CS are delayed by a time td from the normal mode in the data broadcast mode, the buffer memory 25 outputs the video signal D1 with a delay by a time td from the normal mode in the data broadcast mode. The output signal of the buffer memory 25 is supplied to the video signal line drive circuit 3 as the video signal D2.

  Hereinafter, effects of the stereoscopic display device according to the present embodiment will be described. FIG. 6 is a diagram illustrating an example of a change in pixel transmittance in the data broadcast mode for the stereoscopic display device according to the present embodiment. The pixel transmittance changes as shown in FIG. 3 in the normal mode, changes as shown in FIG. 4 in the movie mode, and changes as shown in FIG. 6 in the data broadcasting mode.

  In the data broadcast mode, as in the normal mode, the control signal CB (not shown) is at a high level during the period T1, and the backlight 4 is lit entirely during the period T1. In the data broadcasting mode, the control signals CG and CS and the video signal D2 are delayed by the time td from the normal mode, so that the transmittance of each pixel changes by a time td from the normal mode. For example, the transmittance of the pixel at the top of the screen starts to change at time (ta + td).

  In the stereoscopic display device according to the present embodiment, the crosstalk is reduced at the center of the screen in the normal mode, and the crosstalk is reduced at the lower portion of the screen in the movie mode. In the data broadcasting mode, the control signals CG and CS and the video signal D2 are delayed by time td from the normal mode, so that the crosstalk is reduced at the upper part of the screen.

  For this reason, in the data broadcast mode, the crosstalk becomes larger at the center of the screen and at the lower part of the screen than before, but the crosstalk becomes smaller at the upper part of the screen than before. When the video displayed on the screen is “data broadcasting including text at the top of the screen”, the user pays attention to the top of the screen where the text is displayed. Therefore, in the data broadcast mode, the control signals CG and CS and the video signal D2 are delayed by the time td as compared with the normal mode, thereby reducing the crosstalk at the top of the screen and the visibility of the text of the data broadcast displayed at the top of the screen. Can be increased.

  As described above, in the stereoscopic display device according to the present embodiment, the timing adjustment unit 24 controls the control signal when characters are displayed at a position closer to the first end than the second end (upper screen) in the screen. The first control signals (control signals cg and cs) generated by the generation unit 12 are delayed. In this way, when characters are displayed in the first half of the screen (upper part of the screen), the crosstalk is reduced at the character display position by delaying the image display timing, and the crosstalk is recognized. Can be difficult.

(Third embodiment)
FIG. 7 is a block diagram showing a configuration of a stereoscopic display device according to the third embodiment of the present invention. The stereoscopic display device 30 illustrated in FIG. 7 includes the display control unit 11 and the scanning signal line driving circuit 2 in the stereoscopic display device 10 according to the first embodiment, and the display control unit 31 and the scanning signal line driving circuit 32, respectively. It is a replacement. Among the constituent elements of the present embodiment, the same elements as those of the first and second embodiments are denoted by the same reference numerals and description thereof is omitted.

  FIG. 8 is a block diagram showing details of the display control unit 31. The display control unit 31 illustrated in FIG. 8 includes a control signal generation unit 12, a video determination unit 23, a timing adjustment unit 34, and a buffer memory 35.

  As in the first embodiment, the control signal generator 12 generates control signals cg, cs, cb, and cx. The control signals cg and cs are supplied to the scanning signal line drive circuit 2 and the video signal line drive circuit 3 as control signals CG and CS, respectively. Similar to the second embodiment, the video determination unit 23 outputs a determination signal Q2 having one of values 0, 1, and 2 based on the video signal D1.

  The timing adjustment unit 34 includes delay circuits 16c and 16d and switch circuits 37c and 37d. The delay circuits 16c and 16d delay the control signals cb and cx by time td, respectively. The switch circuit 37c selects the control signal cb when the value of the determination signal Q2 is 0, and otherwise selects the output signal of the delay circuit 16c. The switch circuit 37d selects the control signal cx when the value of the determination signal Q2 is 0, and otherwise selects the output signal of the delay circuit 16d. Output signals of the switch circuits 37c and 37d are supplied to the backlight 4 and the shutter glasses 5 as control signals CB and CX, respectively.

  The scanning signal line driving circuit 32 is obtained by adding a function of switching the driving order of the scanning signal lines G1 to Gm to the scanning signal line driving circuit 2. The display control unit 31 outputs a control signal CY indicating the driving order of the scanning signal lines G1 to Gm to the scanning signal line driving circuit 32. The control signal CY is at a high level when the value of the determination signal Q2 is 2, and is at a low level otherwise. The scanning signal line drive circuit 32 selects the scanning signal lines G1 to Gm in ascending order (in the order of G1, G2,..., Gm) when the control signal CY is at a low level, and scan signal lines when the control signal CY is at a high level. G1 to Gm are selected in descending order (in order of Gm, Gm-1, ..., G1).

  The timing adjustment unit 34 outputs the control signals cb and cx as the control signals CB and CX in the normal mode, and the signals obtained by delaying the control signals cb and cx by the time td in the movie mode and the data broadcasting mode. Output as. Therefore, the control signals CB and CX are delayed by the time td from the normal mode in the movie mode and the data broadcast mode.

  The scanning signal line driving circuit 32 selects the scanning signal lines G1 to Gm in the ascending order in the normal mode and the movie mode, and selects the scanning signal lines G1 to Gm in the descending order in the data broadcasting mode. Therefore, the screen is updated in order from the upper end to the lower end in the normal mode and the movie mode, and is updated in order from the lower end to the upper end in the data broadcasting mode.

  The buffer memory 35 temporarily stores the video signal D1, and outputs the stored video signal in accordance with the timings of CG and CS. In the data broadcasting mode, the scanning signal line driving circuit 32 selects the scanning signal lines G1 to Gm in descending order, so that the buffer memory 35 outputs the video signal D1 in accordance with the selection order of the scanning signal lines G1 to Gm. The output signal of the buffer memory 35 is supplied to the video signal line drive circuit 3 as the video signal D2.

  Hereinafter, effects of the stereoscopic display device 30 will be described. FIG. 9 is a diagram illustrating an example of a change in the transmittance of the pixel in the data broadcasting mode with respect to the stereoscopic display device 30. The pixel transmittance changes as shown in FIG. 3 in the normal mode, changes as shown in FIG. 4 in the movie mode, and changes as shown in FIG. 9 in the data broadcast mode.

  In the data broadcast mode, as in the movie mode, the control signal CB (not shown) is at a high level during the period T2, and the backlight 4 is lit entirely during the period T2. In the data broadcasting mode, since the screen is updated in order from the lower end to the upper end, the transmittance of each pixel changes in the reverse order to that in the normal mode. For example, the transmittance of the pixel at the bottom of the screen starts to change at time ta. The transmittance of the pixel at the center of the screen changes by a time td behind the transmittance of the pixel at the bottom of the screen, and the transmittance of the pixel at the top of the screen changes by a time td behind the transmittance of the pixel at the center of the screen. To do.

  In the stereoscopic display device 30, in the normal mode, the crosstalk is small at the center of the screen, and in the movie mode, the crosstalk is small at the bottom of the screen. In the data broadcasting mode, the control signals CB and CX are delayed by the time td from the normal mode, and the screen is updated in order from the lower end to the upper end, so that crosstalk is reduced at the upper portion of the screen. Therefore, the visibility of the text of the data broadcast displayed on the upper part of the screen can be improved as in the second embodiment.

  As described above, in the stereoscopic display device according to the present embodiment, when a character is displayed at a position closer to the first end than the second end (upper part of the screen) in the screen, the timing adjustment unit 34 generates the control signal. The second and third control signals (control signals cb and cx) generated by the unit 12 are delayed, and the panel driving circuit (the scanning signal line driving circuit 32 and the video signal line driving circuit 3) shifts the screen from the second end to the second end. Update in order toward one end (from bottom to top). When characters are displayed in the first half of the screen (upper part of the screen), the timing for controlling the backlight 4 and the shutter glasses 5 is delayed and the screen is updated in the reverse order. The crosstalk can be reduced at the character display position, making it difficult to recognize the crosstalk.

  In addition, about the three-dimensional display apparatus of this invention, the following modifications can be comprised. The stereoscopic display devices according to the first to third embodiments include a video determination unit that outputs a determination signal indicating characteristics of a video displayed on the screen (more specifically, a position of a character displayed on the screen). It was decided. Instead of this, the stereoscopic display device according to the modified example of the present invention may not include a video determination unit that outputs a determination signal, and may receive a determination signal supplied from the outside.

  10 to 12 are block diagrams illustrating details of the display control unit included in the stereoscopic display device according to the modification of the present invention. The stereoscopic display device according to the first modification includes a display control unit 19 shown in FIG. 10 instead of the display control unit 11. The switch circuits 17c and 17d included in the display control unit 19 operate based on the determination signal Q1 supplied from the outside of the stereoscopic display device. The stereoscopic display device according to the second modification includes a display control unit 29 shown in FIG. 11 instead of the display control unit 21. The switch circuits 17a to 17d included in the display control unit 29 operate based on the determination signal Q2 supplied from the outside of the stereoscopic display device. The stereoscopic display device according to the third modification includes a display control unit 39 shown in FIG. 12 instead of the display control unit 31. The switch circuits 17c and 17d included in the display control unit 39 operate based on the determination signal Q2 supplied from the outside of the stereoscopic display device.

  When the determination signal is supplied from the outside of the stereoscopic display device, the display control unit includes the processing for delaying the video signal D1 and the processing for switching the output order of the video signal D1 outside the stereoscopic display device. The buffer memory can be deleted or the capacity of the buffer memory can be reduced.

  Further, in the stereoscopic display devices according to the first to third embodiments, for example, the video determination unit is configured such that the video displayed on the screen is “movie including subtitles at the bottom of the screen” or “data including text at the top of the screen”. "Broadcast" was decided. The video determination unit may determine whether the video displayed on the screen has a feature other than the above. For example, the video determination unit may more accurately determine the position of characters displayed on the screen, and the timing adjustment unit may switch the relative timing of the control signals CB and CX with respect to the control signals CG and CS in multiple stages.

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal panel 2, 32 ... Scanning signal line drive circuit 3 ... Video signal line drive circuit 4 ... Backlight 5 ... Shutter glasses 6 ... Shutter 10, 30 ... Three-dimensional display device 11, 19, 21, 29, 31, 39 ... Display control unit 12 ... Control signal generation unit 13, 23 ... Video determination unit 14, 24, 34 ... Timing adjustment unit 15, 25, 35 ... Buffer memory 16 ... Delay circuit 17, 27, 37 ... Switch circuit

Claims (10)

A shutter glasses type stereoscopic display device,
A liquid crystal panel that displays a screen;
A panel driving circuit for sequentially updating the screen from the first end toward the second end according to a first control signal, and alternately displaying a left-eye image and a right-eye image on the screen;
A backlight provided on the back side of the liquid crystal panel, which is turned on and turned off in accordance with a second control signal;
Shutter glasses having a left-eye shutter and a right-eye shutter alternately opened according to a third control signal;
A control signal generator for generating the first, second and third control signals;
A stereoscopic display device, comprising: a timing adjustment unit that switches a relative timing of the second and third control signals with respect to the first control signal according to a feature of an image displayed on the screen.   The timing adjustment unit may switch a relative timing of the second and third control signals with respect to the first control signal according to a position of a character displayed on the screen. The three-dimensional display apparatus of description.   When a character is displayed at a position closer to the second end than the first end in the screen, the timing adjustment unit delays the second and third control signals generated by the control signal generation unit The stereoscopic display device according to claim 2, wherein:   When a character is displayed at a position closer to the first end than the second end in the screen, the timing adjustment unit delays the second and third control signals generated by the control signal generation unit. The stereoscopic display device according to claim 3, wherein the panel driving circuit updates the screen in order from the second end toward the first end.   When a character is displayed at a position closer to the first end than the second end in the screen, the timing adjustment unit delays the first control signal generated by the control signal generation unit. The stereoscopic display device according to claim 3.   The control signal generation unit outputs the first, second, and third control signals according to a timing at which the left-eye image and the right-eye image are displayed separately in a central portion of the screen. The three-dimensional display device according to claim 2. A video determination unit that outputs a determination signal indicating the position of the character displayed on the screen based on the input video signal;
The stereoscopic display device according to claim 2, wherein the timing adjustment unit switches a relative timing of the second and third control signals with respect to the first control signal according to the determination signal.   The timing adjustment unit switches relative timings of the second and third control signals with respect to the first control signal in accordance with a determination signal that is supplied from outside and indicates a position of a character displayed on the screen. The stereoscopic display device according to claim 2, wherein:   The stereoscopic display device according to claim 2, wherein the first end is an upper end of the screen and the second end is a lower end of the screen. A liquid crystal panel that displays a screen, a panel drive circuit that sequentially updates the screen from a first end toward a second end according to a first control signal, and alternately displays a left-eye image and a right-eye image on the screen; A backlight which is provided on the back side of the liquid crystal panel and which is fully lit and extinguished according to a second control signal; and shutter glasses having a left-eye shutter and a right-eye shutter which are alternately opened according to a third control signal. A driving method of a stereoscopic display device,
Generating the first, second and third control signals;
Switching the relative timing of the second and third control signals with respect to the first control signal according to the characteristics of the video displayed on the screen.

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