JP2012204980A - Stereoscopic video display system - Google Patents

Abstract

A stereoscopic video display system including a novel type of wireless shutter glasses that does not cause interference with an infrared communication device is provided.
A display device performs display by replacing a part of frames with a predetermined left / right discriminating frame. The shutter glasses detect a display light of the display device and output a signal corresponding to the light intensity, and a portion corresponding to each frame of the right eye image and the left eye image from the signal output from the light receiving means. Means for determining the period, and determining a timing for switching the transmission state of the right shutter and the left shutter based on the determined period, and detecting a portion corresponding to the left / right determination frame from the signal output from the light receiving means And means for discriminating whether the frame following the left-right discrimination frame is a right-eye image frame or a left-eye image frame.
[Selection] Figure 3

Description

  The present invention relates to a stereoscopic image display system for viewing stereoscopic images through shutter glasses.

  In a television receiver, an infrared remote control (hereinafter abbreviated as a remote control) is used. The remote control signal receiving unit is usually disposed at a predetermined position on the front surface of the television receiver (generally, a position that is not easily affected by light irradiation of a fluorescent lamp) via an infrared transmission filter.

  On the other hand, several methods have been proposed as a stereoscopic image display system for viewing a reproduced image as a stereoscopic image. For example, a shutter glasses method has already been put to practical use in a television receiver for home use. In the shutter glasses method, the left eye image and the right eye image are alternately displayed on the display device, and the right eye is switched by switching between transmission and non-transmission of the left and right liquid crystal shutters of the shutter glasses in synchronization with image switching. Is a method in which only the image for the right eye is shown and only the image for the left eye is shown to the left eye.

  When infrared communication is used for transmission of a switching synchronization signal (referred to as a shutter control signal) in wireless shutter glasses, there is a problem that a remote control signal receiving unit cannot receive a correct remote control signal due to interference of the shutter control signal. . Patent Document 1 proposes a method for avoiding this problem, but there still remains a problem that the shutter control signal can interfere with other infrared communication devices.

  Therefore, it is desirable to transmit the shutter control signal using a method other than infrared communication. In Patent Document 2, it is proposed that a stereoscopic video reproduction system including wireless headphones that transmits and receives an acoustic signal by radio waves multiplexes and transmits a shutter control signal to the acoustic signal. However, this configuration can be applied only to shutter glasses integrated with wireless headphones, and it is necessary to provide a radio wave transmission device on the display device, resulting in an increase in cost.

JP-A-8-317427 JP-A-63-15376

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a stereoscopic video display system including wireless shutter glasses of a novel method that does not cause interference with infrared communication devices. It is in.

According to a first aspect of the present invention, there is provided a display device that alternately displays a frame for a right eye image and a frame for a left eye image, a right shutter that is in a transmissive state in accordance with the display of the right eye image, and a left eye image. In a stereoscopic video display system comprising shutter glasses having a left shutter that is in a transmissive state in accordance with display, the display device performs display by replacing some frames with predetermined left-right discriminating frames, The shutter glasses correspond to each frame of the image for the right eye and the image for the left eye from the light receiving means for detecting the display light of the display device and outputting a signal corresponding to the light intensity, and the signal output from the light receiving means. Means for determining the period of the portion and determining timing for switching the transmission state of the right shutter and the left shutter based on the determined period; and output from the light receiving means Means for detecting a portion corresponding to the left / right discrimination frame from the signal to determine whether the frame following the left / right discrimination frame is a right-eye image frame or a left-eye image frame; Provide a system.

  According to a second aspect of the present invention, there is provided a display device that alternately displays a frame for a right eye image and a frame for a left eye image, a right shutter that is in a transmissive state in accordance with the display of the right eye image, and a left eye image. In a stereoscopic video display system comprising shutter glasses having a left shutter that is in a transmissive state in accordance with display, the display device has a blank period between a frame for a right eye image and a frame for the next left eye image. Each of the frames is displayed such that the length and the length of the blank period between the frame of the left-eye image frame and the next frame of the right-eye image are different from each other. A light receiving means for detecting the display light of the apparatus and outputting a signal corresponding to the light intensity; and a period of a portion corresponding to each frame of the image for the right eye and the image for the left eye from the signal output from the light receiving means. Then, based on the determined period, a means for determining the timing for switching the transmission state of the right shutter and the left shutter, and a signal output from the light receiving means determine whether the blank period is longer or shorter. Accordingly, there is provided a stereoscopic video display system having means for determining whether a frame following the blank period is a frame for a right eye image or a frame for a left eye image.

  According to a third aspect of the present invention, there is provided a display device that alternately displays a frame for a right eye image and a frame for a left eye image, a right shutter that is in a transmissive state in accordance with the display of the right eye image, and a left eye image. In a stereoscopic video display system comprising shutter glasses having a left shutter that is in a transmissive state in accordance with display, the display device instantaneously displays a left / right discrimination pulse in a part of a blank period between frames. The shutter glasses detect the display light of the display device and output a signal corresponding to the light intensity, and from the signal output from the light receiving means to each frame of the right eye image and the left eye image Means for determining the period of the corresponding part and determining timing for switching the transmission state of the right shutter and the left shutter based on the determined period; and output from the light receiving means And a means for determining whether a frame following the left / right discrimination pulse is a frame for a right eye image or a left eye image by detecting a left / right discrimination pulse from a received signal. To do.

  ADVANTAGE OF THE INVENTION According to this invention, the stereoscopic video display system which comprises the wireless shutter glasses of a novel system which does not raise | generate interference interference with an infrared communication apparatus can be provided.

1 is a block diagram showing a configuration of a stereoscopic video display system according to a first embodiment. An example of a video signal for synchronizing shutter glasses in the first embodiment. An example of a conversion process from an optical signal to a shutter control signal in the first embodiment. An example of a conversion process from an optical signal to a shutter control signal in the first embodiment. The figure which shows the structure of shutter spectacles. The block diagram which shows the structure of the three-dimensional video display system which concerns on 2nd Embodiment. The figure which shows the timing of the vertical synchronization of the display apparatus in 2nd Embodiment. An example of a conversion process from an optical signal to a shutter control signal in the second embodiment. The block diagram which shows the structure of the three-dimensional video display system which concerns on 3rd Embodiment. An example of light emission for synchronizing shutter glasses in the third embodiment. An example of the conversion process from the optical signal to the shutter control signal in the third embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a stereoscopic image display system using shutter glasses according to the present invention will be described with reference to the accompanying drawings. In the shutter glasses method, the left eye image and the right eye image are alternately displayed on the display device, and the right eye is switched by switching between transmission and non-transmission of the left and right liquid crystal shutters of the shutter glasses in synchronization with image switching. Is a method in which only the image for the right eye is shown and only the image for the left eye is shown to the left eye. Since a known technique can be used for the basic configuration of the shutter glasses type stereoscopic image display system, a detailed description thereof will be omitted, and the configuration for synchronizing the wireless shutter glasses, which is a feature of the present invention, will be mainly described below. Explained.

[First Embodiment]
The first embodiment of the present invention is configured to synchronize shutter glasses by inserting a special right / left discrimination frame in the video display. In the present embodiment, an all black image is used as the left / right discrimination frame. However, the left / right discriminating frame is not necessarily an all-black image, and may be an image having a significant difference (a discriminable difference) in display luminance when compared with a normal display image. For example, an image having a sufficiently low luminance compared to a normal display image or an image having a sufficiently high luminance can be used as the left / right discrimination frame.

  1A and 1B are block diagrams schematically showing the configuration of the stereoscopic video display system according to the first embodiment of the present invention. FIG. 1A shows a main configuration of the display device, and FIG. 1B shows a main configuration of the shutter glasses.

  As shown in FIG. 1A, the display device includes a video processing circuit 11, a panel control circuit 12, and a display panel 13. The video processing circuit 11 is a circuit that generates two frames of video signals (right eye image and left eye image) from a 3D display video signal packed in one frame. The “right eye image” and the “left eye image” are also simply referred to as “right image” and “left image”. The panel control circuit 12 is a circuit that generates a panel control signal for the display panel 13 from the video synchronization signal and generates a drive signal for driving the display panel 13 based on the video signal output from the video processing circuit 11. . The display panel 13 is a panel module that displays an image based on a panel control signal and a drive signal output from the panel control circuit 12. In the present embodiment, an LCD panel including a liquid crystal module, a backlight, and their drive circuits is used, but other types of display panel modules such as a plasma display, a field emission display, and an organic EL display may be used.

  As shown in FIG. 1B, the shutter glasses include a light receiving device (light receiving means) 14, a bandpass filter 15, a comparator 16, a synchronization adjustment circuit 17, a shutter control circuit 18, a right shutter 19 for the right eye, and a left shutter for the left eye. A shutter 20 is provided. The light receiving device 14 is a sensor that receives light in a predetermined wavelength range (here, visible light) and converts it into an electrical signal. The band pass filter 15 is a circuit that allows only an electrical signal having a specific frequency to pass therethrough. The comparator 16 is a circuit that determines an electric signal equal to or greater than a threshold value. The synchronization adjustment circuit 17 is a circuit for adjusting the opening / closing timing of the right shutter 19 and the left shutter 20. The shutter control circuit 18 is a circuit that controls the opening / closing (transmission / non-transmission) of each of the right shutter 19 and the left shutter 20. The right shutter 19 and the left shutter 20 are so-called liquid crystal shutters.

  The video signal for 3D display includes a side-by-side type in which the respective images are arranged on the left and right sides of one frame, a line separation type in which the images are arranged on the top and bottom, and a packing type in which the difference between the left and right sides is compressed into one of the images There is a method. Any type of video signal can be input to the display device of this embodiment.

The video processing circuit 11 automatically discriminates the method of the input video signal and performs 3D according to the method.
The right image and the left image are separated from the display video signal, and the right image frame (right frame) and the left image frame (left frame) are alternately output. For example, when the frame frequency of the input video signal is 60 Hz, a video signal of 120 Hz is output, and when the input video signal is 50 Hz, a video signal of 100 Hz is output. As a result of driving based on the 120 Hz (or 100 Hz) video signal, the display panel 13 alternately displays the right image and the left image at a frame frequency of 120 Hz (or 100 Hz).

  The viewer views the image on the display panel 13 through the shutter glasses. The shutter glasses operate as follows in order to switch between transmission / non-transmission of the right shutter 19 and the left shutter 20 in synchronization with switching between the right image and the left image.

  The light receiving device 14 detects the display light of the display panel 13, converts the light intensity into an electric signal, and outputs it. The light receiving device 14 is preferably attached in parallel with the direction of the glasses and has a narrow directivity in order to reduce the influence of ambient light and effectively receive the optical signal on the screen.

  As will be described later, the ambient light component and the display light component are mixed in the optical signal. Therefore, the ambient light component included in the electrical signal output from the light receiving device 14 is removed by the band pass filter 15. At the same time, the high-frequency component of the display light is also removed by the band pass filter 15.

  Next, the comparator 16 is used to convert the analog signal output from the filter into a digital pulse signal. The threshold value of the comparator 16 may be feedback-controlled to an appropriate value according to the light intensity detected by the light receiving device 14. The synchronization adjustment circuit 17 adjusts the length (pulse width) of the pulse signal in accordance with the frame period (light emission period) of the video signal, and which of the left and right shutters should be in a transmissive state by the method described below. Is notified to the shutter control circuit 18.

  The shutter control circuit 18 controls the opening and closing of the right shutter 19 and the left shutter 20 using the pulse signal output from the synchronization adjustment circuit 17, and switches the transmission state and the non-transmission state of the left and right shutters at an appropriate timing.

  Hereinafter, the operation will be described with reference to FIGS. 2, 3 and 4 by using a specific example of the video signal in the above configuration.

  2A and 2B schematically show video signals used for synchronizing shutter glasses in the first embodiment. FIG. 2A shows a side-by-side input video signal as an example. Reference numerals 21 to 23 denote images of the respective frames including the left image (L) and the right image (R). Among these, in the image 22, the left image is an all black image. FIG. 2B shows each frame of the video signal input to the panel control circuit 12. The right image 24 and the left image 25 correspond to the image 21, the right image 26 and the left image 27 correspond to the image 22, and the right image 28 and the left image 29 correspond to the image 23.

As a method for generating a video signal as shown in FIG. 2B, two operations of the video processing circuit 11 will be described.
The first is a case where an image of a special left / right discrimination frame (here, an all-black image) is embedded in the input 3D display video signal as shown in an image 22. In this case, the video processing circuit 11 converts the input images 21 to 23 of each frame into the images 24 to 29 of the left and right frames for display, as in a general stereoscopic video display device.

  The second case is a case where the image of the left / right discrimination frame is not embedded in the input 3D display video signal, that is, a normal 3D display video signal. In this case, the video processing circuit 11 generates a left / right discrimination frame (an all black image). The left / right discriminating frame can be inserted at a fixed period with respect to the display video signal, but is preferably inserted at the timing of the scene change. This is because, in the case of a scene change, the viewer hardly detects any sense of discomfort or discomfort due to the insertion of the left / right discrimination frame. For example, the video processing circuit 11 obtains an APL (average luminance level) of each frame of the video signal, and the scene change is detected as a scene change when the APL value fluctuates by a predetermined threshold or more (for example, 10% or more). Can be used. In addition, a scene change may be detected from a change in motion vector, a change in sound, or the like. In the example of FIG. 2B, only the frame of the left image 27 is replaced with the left / right determination frame (all black image), but the frame of the right image may be replaced with the left / right determination frame, or the right image and the left image Both of these frames may be replaced with left and right determination frames.

  FIG. 3A to FIG. 3G are diagrams illustrating a conversion process from an optical signal to a shutter control signal, which is performed in the shutter glasses. FIG. 3A shows a temporal change in the intensity of the optical signal detected by the light receiving device 14, where the horizontal axis represents time and the vertical axis represents light intensity. FIG. 3B shows the frequency characteristic of the electrical signal proportional to the intensity of the optical signal in FIG. 3A, where the horizontal axis is frequency and the vertical axis is intensity. FIG. 3C shows the frequency characteristic of the electric signal that has passed through the band-pass filter 15. FIG. 3D shows the time change of the electrical signal that has passed through the band-pass filter 15, where the horizontal axis represents time and the vertical axis represents voltage. 3E is an electrical signal that has passed through the comparator 16, FIG. 3F is an electrical signal that has passed through the synchronization adjustment circuit 17, FIG. 3G is a shutter control signal for the right shutter 19, and FIG. 3H is a shutter control signal for the left shutter 20. Show.

  Since the optical signal received by the light receiving device 14 (FIG. 3A) includes environmental light components such as illumination and high frequency components of display light of the display panel 13, the frequency characteristics are as shown in FIG. 3B. Yes. Therefore, the bandpass filter 15 is used to extract only the frequency component of the display image. For example, when the frame frequency of the display image is 120 Hz, an electric signal (FIG. 3D) having frequency characteristics as shown in FIG. 3C is extracted by passing the bandpass filter 15 having a frequency range of 120 Hz ± 20 Hz. Can do.

  This electric signal is pulsed by the comparator 16 (FIG. 3E). The threshold at this time is adaptively determined according to the strength of the electric signal. For example, an average voltage for several seconds of an analog electric signal output from the light receiving device 14 or the band pass filter 15 may be created by an integration circuit, and the average voltage may be used as a threshold value.

  In the synchronization adjustment circuit 17, the pulse width of the pulse signal (FIG. 3E) output from the comparator 16 is corrected to a pulse width corresponding to the frame period (light emission period) of the video signal. Since the time width of the frame period of the video signal is uniquely determined from the frame frequency of the video signal, the display mode of the display panel 13, and the like, the synchronization adjustment circuit 17 adjusts the rise and fall of the pulse signal according to the time width. Stretch the timing. The synchronization adjustment pulse signal thus obtained is shown in FIG. 3F.

  The shutter control circuit 18 separates every other synchronization adjustment pulse signal to obtain a right shutter control signal (FIG. 3G) and a left shutter control signal (FIG. 3H). Then, the shutter control circuit 18 opens / closes the right shutter 19 according to Hi / Low of the right shutter control signal, and opens / closes the left shutter 20 according to Hi / Low of the left shutter control signal. Thus, transmission / non-transmission of the left and right shutters can be switched in synchronization with frame switching of the display video (FIG. 3A).

  According to the above method, the opening / closing timing of the shutter can be determined based on the light / dark cycle of the display image detected on the shutter glasses side. However, this alone cannot determine whether the image is the right image or the left image, and therefore cannot determine which of the right shutter 19 and the left shutter 20 should be opened (closed). Therefore, in this embodiment, the left / right discrimination is performed using the left / right discrimination frame shown in FIG. 2B.

  FIG. 4A to FIG. 4F are diagrams for explaining a conversion process from an optical signal to a shutter control signal when there is a left / right discrimination frame, which is performed in the shutter glasses. 4A shows the time change of the intensity of the optical signal detected by the light receiving device 14, FIG. 4B shows the time change of the electric signal passed through the bandpass filter 15, FIG. 4C shows the electric signal passed through the comparator 16, and FIG. , An electric signal passing through the synchronization adjustment circuit 17. 4E shows a shutter control signal for the right shutter 19, and FIG. 4F shows a shutter control signal for the left shutter 20. 4A to 4F are the same as the corresponding diagrams in FIGS. 3A to 3G.

  The left / right discrimination frame in the first embodiment is an all-black screen as described with reference to FIG. 2B. When the all-black screen is displayed, the display brightness at that time is naturally small, so that the light intensity detected by the light receiving device 14 changes with time as if a part of 41 is missing as shown in FIG. 4A. .

  If the electric signal obtained by converting the light intensity is passed through the band-pass filter 15, as shown in FIG. When this voltage waveform is passed through the comparator 16, a pulse signal as shown in FIG. 4C is obtained. This pulse signal is missing a single pulse at 43. If this pulse signal is passed through the synchronization adjustment circuit 17, it becomes as shown in FIG. 4D.

  The shutter control circuit 18 controls the LCDs of the right shutter 19 and the left shutter 20 alternately in a transmissive state as shown in FIGS. 3G and 3H until the pulse is lost. When the shutter control circuit 18 detects that the pulse is missing as shown in 44 of FIG. 4D, the shutter control circuit 18 understands that the next pulse corresponds to the right image, and the right shutter 19 enters the transmission state with the pulse. Control to be.

  Then, even if the right shutter 19 is in the transmissive state as in the pulse 45 in FIG. 4E in the portion 44 lacking the pulse, the left shutter 20 is not in the transmissive state in the next pulse, but in FIG. 4E. Like the pulse 46, the right shutter 19 enters the transmission state. After that, the left and right shutters are controlled so as to be alternately transmissive.

  According to the configuration described above, by inserting a predetermined left / right discriminating frame into a scene change or the like, it is possible to discriminate left and right as well as matching the timing of opening / closing the shutter and image display. Therefore, even if the left and right sides of the shutter glasses do not coincide with the left and right sides of the display device, the left and right sides of the shutter glasses and the display device can be automatically synchronized.

  FIG. 5 is a diagram showing the structure of the shutter glasses. In the figure, 51 is a display device capable of displaying a stereoscopic image, and 13 is a display panel. Reference numeral 52 denotes shutter glasses, 14 denotes a light receiving device, 19 and 20 denote left and right LCD shutters, 53 denotes a light guide path to the light receiving device 14, and 54 denotes a circuit case. Reference numeral 55 denotes a viewer's eye, and reference numeral 56 denotes an illumination device.

In order to realize the operation described above, it is necessary to distinguish between the light emitted from the display panel 13 and the light emitted from the illumination device 56 in the optical signal detected by the light receiving device 14. When an incandescent bulb, an inverter type fluorescent lamp, LED lighting, or the like is used as the illumination device 56, the component of illumination light can be removed by the bandpass filter 15 in the circuit unit case 54, so that there is no problem. A particular problem occurs when the light emission frequency of the lighting device 56 and the frame frequency of the display panel 13 are the same. In this case, it is difficult to remove the illumination light component by the band pass filter 15.

  Therefore, in the present embodiment, a method of improving the directivity of the light receiving device 14 by adding the light guide path 53 in front of the light receiving device 14 so that only a small amount of light from the illumination device 56 enters the light receiving device. Have taken.

  Furthermore, when the emission spectrum of the display device is known, it is possible to reduce the received light intensity of external light by installing an optical filter corresponding to the emission spectrum of each primary color of the display device in front of the light receiving device 14. For example, this is an effective method when the emission spectrum of each primary color such as a three-primary-color LED backlight is in a narrow band.

[Second Embodiment]
The second embodiment of the present invention is configured to synchronize shutter glasses by changing the display timing (vertical synchronization) of the left image and the right image from those of a normal display device.

  6A and 6B are block diagrams schematically showing the configuration of the stereoscopic video display system according to the first embodiment of the present invention. FIG. 6A shows a main configuration of the display device, and FIG. 6B shows a main configuration of the shutter glasses.

  The display device of this embodiment has a synchronous modulation circuit 211. The shutter glasses include a band pass filter 212 having different characteristics from the band pass filter 15 of the first embodiment, and a shutter control circuit 213 having an operation different from that of the shutter control circuit 18 of the first embodiment. Since the other configuration is the same as that of the first embodiment, the same reference numerals as those in FIGS. 1A and 1B are attached and description thereof is omitted.

  7A to 7C show an operation in which the synchronous modulation circuit 211 changes the timing of the synchronization signal of the display device in order to enable the left and right discrimination with the shutter glasses. FIG. 7A is a vertical synchronization (Vsync) signal input to the synchronous modulation circuit 211. FIG. 7B is a data enable signal output from the synchronous modulation circuit 211. FIG. 7C shows a drive signal (data signal) output from the panel control circuit 12.

  As in the first embodiment, the video processing circuit 11 separates the right image and the left image from the original 3D display video signal, and alternately outputs each image at a frame frequency of 120 Hz.

  The vertical synchronization signal (FIG. 7A) input to the synchronous modulation circuit 211 has an equal period of 120 Hz. The synchronous modulation circuit 211 generates a new data enable signal (FIG. 7B) based on the vertical synchronization signal. In the new data enable signal, the length of the delay amount (back porch) from the vertical synchronization signal differs between the right image and the left image. Specifically, in the case of the right image, the back porch is lengthened as indicated by 221, and in the case of the left image, the back porch is shortened as indicated by 222.

  Accordingly, the width of the blank period (non-display period between two frames) of the drive signal (FIG. 7C) output from the panel control circuit 12 is different. By driving the display panel 13 based on such a drive signal, the right image is displayed after the long blank period 223 and the left image is displayed after the short blank period 224. As a result, a long part and a short part of a dark period (non-display period) without display light are alternately generated. This is detected by shutter glasses, and left and right are discriminated.

  FIG. 8A to FIG. 8G are diagrams for explaining a conversion process from an optical signal to a shutter control signal, which is performed in the shutter glasses. FIG. 8A shows a temporal change in the intensity of the optical signal detected by the light receiving device 14, where the horizontal axis represents time and the vertical axis represents light intensity. FIG. 8B shows the frequency characteristic of the electrical signal proportional to the intensity of the optical signal in FIG. 8A, where the horizontal axis is frequency and the vertical axis is intensity. FIG. 8C shows the frequency characteristic of the electrical signal that has passed through the band-pass filter 212. FIG. 8D shows the time change of the electrical signal that has passed through the band-pass filter 212, where the horizontal axis represents time and the vertical axis represents voltage. 8E shows an electrical signal that has passed through the comparator 16, FIG. 8F shows an electrical signal that has passed through the synchronization adjustment circuit 17, FIG. 8G shows a shutter control signal for the right shutter 19, and FIG. 8H shows a shutter control signal for the left shutter 20. Show.

  The optical signal received by the light receiving device 14 (FIG. 8A) includes environmental light components such as illumination and high frequency components of display light of the display panel 13. The display light of this embodiment has a waveform such that a pair of peaks 231 and 232 corresponding to the right image and the left image appears at a period of 60 Hz. Therefore, in the frequency characteristic, two peaks appear at 60 Hz and 120 Hz as shown in FIG. 8B.

Therefore, the bandpass filter 212 is used to extract only the frequency component of the display image. For example, if the band-pass filter 212 having a frequency range of 40 to 140 Hz is passed through, an electric signal as shown in FIG. 8D having the frequency characteristics as shown in FIG. 8C can be obtained. This electric signal is a signal whose voltage periodically changes. However, 235 where the low voltage portion is a short time and 236 where the low voltage portion is a long time alternately appear.
This electrical signal is pulsed by the comparator 16 as in the first embodiment (FIG. 8E). The threshold at this time is determined by the same means as in the first embodiment.

In the synchronization adjustment circuit 17, the pulse width of the pulse signal (FIG. 8E) output from the comparator 16 is corrected to a pulse width corresponding to the frame period (light emission period) of the video signal. The method for expanding and contracting the pulse width is the same as in the first embodiment.
Then, the shutter control circuit 213 separates every other synchronization adjustment pulse signal to obtain a right shutter control signal (FIG. 8G) and a left shutter control signal (FIG. 8H). At this time, the shutter control circuit 213 checks the length (width) of the blank period of the synchronization adjustment pulse signal, and the pulse following the wider blank period 237 continues to the right shutter pulse and the narrower blank period 238. The pulse is determined as a pulse for the left shutter.

  According to the configuration described above, by adjusting the vertical synchronization cycle, the opening / closing of the shutter and the timing of image display can be matched, and the left and right can also be discriminated. Further, since it is not necessary to replace one frame of the video signal with the left / right discriminating frame as in the first embodiment, it is possible to prevent missing of the video.

[Third Embodiment]
In the third embodiment of the present invention, the shutter glasses are synchronized by causing the display screen to emit light instantaneously during the vertical blank period of the video signal (this instantaneous light emission is referred to as a right / left discrimination pulse).

  9A and 9B are block diagrams schematically showing the configuration of the stereoscopic video display system according to the third embodiment of the present invention. FIG. 9A shows a main configuration of the display device, and FIG. 9B shows a main configuration of the shutter glasses.

The display device of this embodiment has a panel control circuit 311 that operates differently from that of the first embodiment. The shutter glasses also include a high-pass filter 312, a difference circuit 313 that takes a signal difference, a comparator 314 that pulses the output of the difference circuit 313, and a shutter control circuit 315 that operates differently from that of the first embodiment. Yes. Since the other configuration is the same as that of the first embodiment, the same reference numerals as those in FIGS. 1A and 1B are attached and description thereof is omitted.

  10A and 10B are diagrams illustrating the light emission timing of the display panel 13 for performing synchronization and right / left discrimination of the shutter glasses. FIG. 10A is a diagram illustrating a time change of the vertical synchronization signal, in which the horizontal axis represents time and the vertical axis represents voltage. FIG. 10B is a diagram illustrating a temporal change in the light emission luminance of the display panel 13. In FIG. 10B, reference numeral 321 denotes a blank period, and reference numeral 322 denotes a light emission period provided during the blank period.

  As in the first embodiment, the video processing circuit 11 separates the right image and the left image from the original 3D display video signal, and alternately outputs each image at a frame frequency of 120 Hz. The vertical synchronizing signal has a period of 120 Hz as shown in FIG. 10A.

  In the blank period of the vertical synchronization signal (FIG. 10A), the panel control circuit 311 sets the blank period after the right image as a normal blank period 321, and sometimes blanks as 322 in the blank period after the left image. Light only for a moment during the period.

Means for causing light emission varies depending on the type of the display panel 13. For example, in a liquid crystal display, by performing backlight control, a black screen is set during a normal blank period, and the backlight is turned on only momentarily during the light emission period. In the plasma display, since the display is performed by the subfield, as the lighting during the blank period, the subfield is lit only once during the blank period to display the entire white or gray screen. In a line drive type display panel such as a field emission display or an organic EL display, a gray gradation is written in the data side drive IC, and the scan side drive IC may be scanned at high speed from top to bottom.
The light emission during the blank period is preferably performed with an interval of about 10 seconds so as not to stand out.

  Note that it is preferable to make it difficult for viewers to understand that light emission during the blank period is not perceived as a hindrance to the display. For this purpose, it is desirable to detect a scene change and emit a left / right discrimination pulse in a blank period between frames undergoing a scene change.

  FIG. 11A to FIG. 11K are diagrams for explaining a conversion process from an optical signal to a shutter control signal performed in the shutter glasses. 11A shows a temporal change in the intensity of the optical signal detected by the light receiving device 14, and FIG. 11B shows a frequency characteristic of the electric signal proportional to the intensity of the optical signal in FIG. 11A. FIG. 11C shows the frequency characteristic of the electric signal that has passed through the band-pass filter 15, and FIG. 11D shows the frequency characteristic of the electric signal that has passed through the high-pass filter 312. FIG. 11E shows the time change of the electric signal passing through the band pass filter 15, and FIG. 11F shows the time change of the electric signal passing through the high pass filter 312. FIG. 11G shows the time change of the electrical signal through the difference circuit 313, and FIG. 11H shows the time change of the electrical signal through the comparator 314. 11I shows an electrical signal that has passed through the synchronization adjustment circuit 17, FIG. 11J shows a shutter control signal for the right shutter 19, and FIG. 11K shows a shutter control signal for the left shutter 20.

  The optical signal (FIG. 11A) received by the light receiving device 14 includes instantaneous light emission (left / right discriminating pulse) during the blank period, as indicated by the broken line. Therefore, in the frequency characteristic, a high frequency component corresponding to the left / right discrimination pulse appears as indicated by a broken line in FIG. 11B.

First, as in the first embodiment, only the frequency component of the display image is extracted through the bandpass filter 15 (FIGS. 11C and 11E). For example, a band pass filter that extracts a frequency range of 120 Hz ± 20 Hz may be used.

  On the other hand, the frequency component corresponding to the left / right discrimination pulse during the blank period is extracted through the high-pass filter 312 (FIGS. 11D and 11F). For example, a high pass filter that extracts only a frequency range of 1 kHz or higher may be used.

  Next, in order to remove the high-frequency component due to the display content from the electrical signal of FIG. 11F, the difference circuit 313 subtracts the signal of FIG. 11E from the signal of FIG. 11F to obtain the signal of FIG. It can be seen that a portion 333 corresponding to the left / right discrimination pulse is extracted. When this electric signal is pulsed by the comparator 314, the pulse signal of FIG. 11H is obtained. This pulse signal includes a pulse 334 corresponding to the left / right discrimination pulse. In this embodiment, this pulse 334 is used for the left and right discrimination of the shutter glasses.

  Until a pulse 334 is detected, the shutter control circuit 315 performs control so that the LCDs of the right shutter 19 and the left shutter 20 are alternately transmissive as shown in FIGS. 3G and 3H. When the shutter control circuit 315 detects the pulse 334, the shutter control circuit 315 understands that the next pulse in the output signal (FIG. 11I) of the synchronization adjustment circuit 17 corresponds to the right image.

  Then, even if the right shutter 19 is in the transmission state at the time of the pulse 334 as in the pulse 335 in FIG. 11J, the left shutter 20 is not in the transmission state in the next pulse, but the pulse 336 in FIG. Thus, the right shutter 19 is in the transmissive state. After that, the left and right shutters are controlled so as to be alternately transmissive.

  According to the configuration of the present embodiment, the screen is emitted for a moment during the vertical blank period, and is detected on the shutter glasses side, thereby automatically synchronizing the left and right of the shutter glasses with the display device as in the first embodiment. be able to. Note that light emission for shutter glasses synchronization may be performed during a vertical blank period between frames with a scene change. This is because if the scene changes, the content of the display image changes greatly, and there is an advantage that the viewer is not likely to notice the light emission for synchronizing the shutter glasses.

  As described above, in the configuration of each embodiment of the present invention, since the stereoscopic shutter glasses are synchronized using the display image (display light) of the display device, the infrared communication device such as a remote controller is used. There is no interference and interference. Compared to a configuration that multiplexes with an audio signal or transmits a signal by radio waves, it can be realized by making a small change to the video processing circuit of a normal 2D display device, thus producing a stereoscopic video display system at a low cost. There is also an advantage of being able to.

  In the above embodiment, it is assumed that a 3D moving image is displayed on the television device, but the present invention is applicable to various display devices such as a computer monitor, and the display content is not limited to a moving image. It can also be applied to still images.

  11: Video processing circuit, 13: Display panel, 14: Light receiving device, 18: Shutter control circuit, 19: Right shutter, 20: Left shutter

Claims (4)

A display device that alternately displays a frame for a right eye image and a frame for a left eye image, a left shutter that is in a transmissive state in accordance with the display of the right eye image, and a left in a transmissive state in accordance with the display of the left eye image In a stereoscopic image display system comprising shutter glasses having a shutter,
The display device performs display by replacing a part of the frames with a predetermined left / right determination frame,
The shutter glasses are
A light receiving means for detecting the display light of the display device and outputting a signal corresponding to the light intensity;
The timing of the part corresponding to each frame of the image for the right eye and the image for the left eye is determined from the signal output from the light receiving means, and the timing for switching the transmission state of the right shutter and the left shutter based on the determined period. Means to determine,
Means for determining whether a frame following the left / right discrimination frame is a right eye image frame or a left eye image frame by detecting a portion corresponding to the left / right discrimination frame from a signal output from the light receiving means. And a stereoscopic video display system.   The stereoscopic video display system according to claim 1, wherein the left / right discrimination frame is an all-black image. A display device that alternately displays a frame for a right eye image and a frame for a left eye image, a left shutter that is in a transmissive state in accordance with the display of the right eye image, and a left in a transmissive state in accordance with the display of the left eye image In a stereoscopic image display system comprising shutter glasses having a shutter,
The display device includes: a blank period length between a right eye image frame and a next left eye image frame; and a blank space between a left eye image frame and a next right eye image frame. Each frame is displayed so that the lengths of the periods are different from each other.
The shutter glasses are
A light receiving means for detecting the display light of the display device and outputting a signal corresponding to the light intensity;
The timing of the part corresponding to each frame of the image for the right eye and the image for the left eye is determined from the signal output from the light receiving means, and the timing for switching the transmission state of the right shutter and the left shutter based on the determined period. Means to determine,
By determining whether the blank period is longer or shorter from the signal output from the light receiving means, it is determined whether the frame following the blank period is a right eye image frame or a left eye image frame. Means for displaying a stereoscopic image. A display device that alternately displays a frame for a right eye image and a frame for a left eye image, a left shutter that is in a transmissive state in accordance with the display of the right eye image, and a left in a transmissive state in accordance with the display of the left eye image In a stereoscopic image display system comprising shutter glasses having a shutter,
The display device instantaneously displays a left / right discrimination pulse in a part of a blank period between frames,
The shutter glasses are
A light receiving means for detecting the display light of the display device and outputting a signal corresponding to the light intensity;
The timing of the part corresponding to each frame of the image for the right eye and the image for the left eye is determined from the signal output from the light receiving means, and the timing for switching the transmission state of the right shutter and the left shutter based on the determined period. Means to determine,
Means for detecting whether a frame following the left / right discrimination pulse is a frame for a right eye image or a frame for a left eye image by detecting a left / right discrimination pulse from a signal output from the light receiving means. A stereoscopic image display system characterized by this.

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