JPH0720273B2 - 3D television equipment - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stereoscopic television device, and more specifically to a polarization type stereoscopic television device using a liquid crystal display device having a signal storage function.

[Conventional technology]

The stereoscopic television device has an advantage that a captured image can be observed in three dimensions, and its principle has been known for a long time, but in recent years, it has been put to practical use as a moving image.
In order to realize stereoscopic vision with a television device, as shown in FIG. 7, the TV device alternately images the right-eye image and the left-eye image, and the viewer views the alternate image with his right and left eyes. Try to observe alternately.

In FIG. 7, 201 and 202 are cameras for forming video signals for the right eye and the left eye, respectively, and the mixer 203 alternately switches the right eye signal and the left eye signal for each field.
Send to TV receiver 204. The mixer 203, for example, makes an odd field an image for the right eye and an even field an image for the left eye. Therefore, the TV receiver 204 has an image from the right camera 201 in the odd field and a left camera 202 in the even field.
There is an image from. The shutter drive circuit 205 receives the vertical synchronizing signal of the mixed video signal from the TV receiver 204, and controls the opening and closing of the shutters 206 and 207. Shutters 206 and 207 are PLZ
It is made of a material that can electrically block light transmission at high speed, such as T and liquid crystal. For example, the drive circuit 205 opens the right-eye shutter 206 and closes the left-eye shutter 207 when the right-eye image appears on the TV receiver 204, and closes the right-eye shutter 207 when the left-eye image appears on the TV receiver 204. Close 206 and shutter 207 for the left eye
open. In this way, the viewer can
You will observe the right-eye image and the left-eye image substantially simultaneously,
A stereoscopic image is realized.

Another method of realizing stereoscopic vision is a method of utilizing polarized light. In this method, two sets of a polarizer and an analyzer are used to observe a right-eye image and a left-eye image with the right eye and the left eye, respectively.

On the other hand, a liquid crystal display element has come to be used as a display device for video signals because of its features such as small size, flat plate, and low power consumption. As a liquid crystal display device for that purpose, a matrix type display as shown in FIG. 5 is adopted because it is a two-dimensional display, and its typical driving method is as follows.
There are a simple matrix address method and an active matrix address method.

As shown in FIG. 5, the matrix type display is provided with a plurality of X-axis electrodes (scanning electrodes) and Y-axis electrodes (display electrodes) which are orthogonal to each other on each of two substrates sandwiching the liquid crystal, and the X-axis electrodes are provided. An image signal voltage is applied to the Y-axis electrode while displaying the scanning voltage in order to display an image. In the simple matrix addressing method, simply the X axis and the Y axis, for example,
A voltage is applied to the X ₂ axis and the Y ₂ axis to select the pixel (X ₂ , Y ₂ ). However, in this method, the intersection point (X ₂ , Y ₂ ) in FIG.
Pixels in the shaded area other than (half-selected pixels) are 1 / of the selected pixel
A voltage of 2 is applied, which causes cross talk and deteriorates display characteristics.

On the other hand, the active matrix addressing method is the sixth
As shown in the figure, for each pixel, connect active elements such as transistors and FETs, switch elements and capacitors,
The contrast is increased by continuously driving the target pixel with the accumulated charge of the capacitor.

Among the liquid crystal elements for display, those capable of achieving a large number of pixels and high definition and achieving a large screen and high resolution have been developed. For example, a ferroelectric liquid crystal having a chiral smectic phase has a high-speed optical switching response, a memory function, that is, a function of maintaining the previous display content unless the next signal is written or a reset process is performed, and a time division number. The feature is that the image quality does not deteriorate even when the size becomes large, and it is used for color liquid crystal TVs. Details of this liquid crystal are described in U.S. Pat. No. 4,367,924 and JP-A-59-193427.

[Problems to be solved by the invention]

In the stereoscopic television device using the optical shutter shown in FIG. 7, the right-eye image and the left-eye image are alternately observed for each field or each frame, so that the screen flickers and flicker occurs, which is not easy to see. not,
Further, since it has a complicated structure for opening and closing the optical shutter of the spectacles in synchronism with the video signal, it is lacking in convenience as a stereoscopic image reproducing system.

Therefore, the present invention has no flicker due to flicker,
An object of the present invention is to provide a stereoscopic television device that does not require an optical shutter for glasses.

[Means for solving problems]

The stereoscopic television device according to the present invention is provided with an analyzing member for polarized light which is orthogonal to each other in the right eye and the left eye of the stereoscopic eyeglasses,
A stereoscopic television device that realizes stereoscopic vision by observing a left-eye image with the left eye and a right-eye image with the right eye through the light analysis member, using a liquid crystal display device having a signal storage function as a display device, The pixels of the liquid crystal display device are divided into alternating right-eye pixel columns and left-eye pixel columns, a right-eye pixel column is provided with a polarizing member having a polarization corresponding to the right-eye detecting member of the spectacles, and the left-eye pixel group is spectacles. A polarizing member having a polarization corresponding to the left-eye analyzing member is provided, and the right-eye video signal is supplied to the right-eye pixel column, and the left-eye video signal is supplied to the left-eye pixel column.

[Action]

In the present invention, a liquid crystal display device having a signal storage function is used as the display device, and the signal storage function and the information controllability in pixel units are utilized. That is, on the playback screen, the right eye pixel row and the left eye pixel row are interlaced and arranged,
A right-eye video signal is applied to the right-eye pixel column, and a left-eye video signal is applied to the left-eye pixel column. Polarizing plates orthogonal to each other are arranged in front of the right-eye pixel row and the left-eye pixel row, and corresponding analyzers are fitted to the right and left eyes of the spectacles for observation. This eliminates the need for optical shutters on the glasses.
Further, due to the signal storage function of the liquid crystal display device, both of the pixel columns maintain the previous display until the display contents are updated, so that there is no non-display period for each eye and flicker is reduced.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1A is a block diagram of an embodiment of a stereoscopic television device according to the present invention. In FIG. 1A, the same members as those shown in FIG. 7 are designated by the same reference numerals. In Figure 1A,
The change-over switch 10 switches between the stereoscopic video signal from the mixer 203 shown in FIG. 7 and the stereoscopic video signal reproduced from the VTR device 12, and a known intermediate frequency amplification and AGC circuit 20.
Supply to. The mixer 203 is a circuit that alternately outputs the right-eye video signal from the camera 201 and the left-eye video signal from the camera 202 to the switch 12 for each field.

The video signal detection circuit 22 separates the video signal and the audio signal from the output of the intermediate frequency amplification and AGC circuit 20, and of the output signals of the circuit 22, the audio signal is converted into audio by the audio circuit 24 and the speaker 26.

The video signal in the output of the video signal detection circuit 22 is amplified by the video signal amplifier 28, converted into a digital signal by the A / D converter, and sequentially stored in the line memory 32 for each scanning line. The sync separation circuit 34 is a video signal detection circuit.
Separate horizontal and vertical sync signals from 22 outputs,
The signals are supplied to the horizontal oscillation circuit 36 and the vertical oscillation circuit 38, respectively. The timing circuit 40 is a clock for controlling the A / D conversion in the A / D converter 30, writing / reading to / from the line memory 32, and the shift register 42 according to the outputs of both the oscillation circuits 36 and 38. Form and output signals 40a, 40b, 40c.

The shift register 42 includes a scan drive circuit 44 so that the scan drive circuit 44 sequentially drives the scan electrodes of the liquid crystal display 46.
Apply timing pulse to 44. Further, the video information data read from the line memory 32 is converted by the modulation drive circuit 48 into a signal suitable for driving the liquid crystal display 46, and drives the liquid crystal of the corresponding pixel.

The liquid crystal display 46 is a matrix type display having a memory (signal storage) function for holding a previous signal unless the next signal input or signal clear processing is performed, and is preferably a liquid crystal of a chiral smectic phase described later. Become. In this liquid crystal display 46, as shown in FIG. 1B, polarizing plates L (L ₁₁ , L ₁₂ , ...
…, L ₁₃ ,…) and R (R ₁₁ , R ₁₂ ,…, R ₁₃ ,…)
Are arranged for each pixel, and therefore the right-eye pixel row and the left-eye pixel row are arranged alternately. Then, the scan drive circuit 44 sequentially drives the pixel columns in FIG. 1B in the case of the right-eye video signal, and sequentially drives the pixel columns L in FIG. 1B in the case of the left-eye video signal.

Since both drive circuits 44 and 48 do not have a refresh function for refreshing the pixels of the liquid crystal display for each field, the liquid crystal display 46 displays the previous information until it is accessed again for each pixel and new information is written. Keep doing Therefore, in this embodiment, since the information (for example, the left-eye video signal in the odd field and the right-eye video signal in the even field) is different in the odd field and the even field, and the pixel to be accessed is also different, each pixel is one frame. It will be rewritten once. However, because of the memory function of the liquid crystal display 46, all pixels are constantly displayed except when rewriting, so that image information is always input to both eyes, and the screen does not flicker.

Check the relationship between the polarizer and the eyeglass analyzer for the right and left eyes.
Shown in Figure 1C. Further, in the case of the same liquid crystal, it is difficult to make the polarization angle different for each pixel between the high voltage and the low voltage. Therefore, in this embodiment, the polarity of the drive voltage is reversed and controlled.

Next, a ferroelectric liquid crystal device having a chiral smectic phase (CS phase) will be described. CS with ferroelectricity
In addition to the memory function, the liquid crystal display has the features of being capable of high-speed optical switching, and being capable of displaying images without deterioration of image quality even when the number of time divisions is large, It is suitable for liquid crystal color televisions for the purpose of flicker-free multi-pixel high-definition display. In a normal TN type liquid crystal, it is difficult to increase the number of scanning lines because the threshold characteristic is not sharp, and it is not suitable for a large screen or a high resolution display.

Ferroelectric liquid crystal of CS phase has an asymmetric carbon atom in the molecule,
It is characterized by having a dipole moment in the direction perpendicular to the long axis of the molecule. This molecular arrangement has a spiral structure as shown in FIG. 2, and the direction of spontaneous polarization is rotating along the spiral axis, so that the dipole moment is canceled out as a whole.

However, when the thickness of the liquid crystal cell is made smaller than the spiral pitch, the spiral is unraveled, and the spontaneous polarization is directed upwards with respect to the paper surface (the third
(A)) or downward (FIG. 3 (b)). When a DC voltage is applied to the liquid crystal cell in such a state, the direction of spontaneous polarization can be aligned in one direction throughout the liquid crystal cell. The states of FIGS. 3 (a) and 3 (b) are maintained as they are even when the voltage is turned off, and the direction of spontaneous polarization is reversed by applying a voltage of the opposite polarity.

Since the spontaneous polarization acts directly on the electric field, switching can be performed in an order of magnitude shorter than that of a nematic liquid crystal having no spontaneous polarization. By the way, the switching time of a normal nematic liquid crystal cell is several tens of milliseconds, while that of a chiral smectic liquid crystal can be 0.5 μsec, which enables high-speed operation that is about four orders of magnitude faster.

A method of driving a matrix type display using such a ferroelectric liquid crystal will be briefly described.

FIG. 4A (a) is a schematic view of a cell 110 having a matrix electrode structure in which a ferroelectric liquid crystal compound is sandwiched. 112
Is a scan electrode group, and 113 is a signal electrode group. FIG. 4A (b) shows an electric signal applied to the selected scan electrode 112 (s), and FIG. 4 (c) shows an unselected scan electrode.
The electric signal applied to 112 (n) is shown in FIG.
Shows the electric signal applied to the selected (with information) signal electrode 113 (s), and FIG. 8 (e) shows the electric signal applied to the unselected (without information) signal electrode 13 (n). Shows the signal. 4A, (b), (c), (d), (e)
The horizontal axis of represents the time, and the vertical axis represents the voltage. When displaying a moving image, the scan electrodes 112 are sequentially and periodically selected.

The threshold voltage for giving the first stable state of the liquid crystal cell having bistability is V _th1 , the threshold for giving the second stable state is −V _th2 , and the voltage value V is V <V _th1 < 2V,-
It is assumed that both V> −V _th2 > −2V are satisfied. The voltage applied to the selective scan electrode 112 (s) is an alternating voltage which is ₂ V in the period t ₁ and −V in the period t ₂ as shown in FIG. 4A (b). The voltage applied to the non-selected scan electrode 112 (n) is the fourth
It is 0 (ground) as shown in FIG. On the other hand, the voltage applied to the selection signal electrode 113 (s) is 0 in the period t ₁ and V in the period t ₂ as shown in FIG. 4A (d), and is applied to the non-selection signal electrode 113 (n). The voltage is 0 (ground) as shown in FIG. 4A (e).

FIG. 4B shows the waveform of the voltage applied to each pixel when such a voltage is applied to the scan electrode 112 and the signal electrode 113. Parts (a), (b), (c), and (d) of FIG. 4B correspond to the pixels A, B, C, and D of FIG. 4A (a), respectively. That is,
As can be seen from FIG. 4B, the voltage −2V exceeding the threshold voltage −V _th2 is applied to all the pixels on the selected scanning line during the first period t ₁ , so that the pixels are first brought into the second stable state. . Then, in the second period t ₂ , the pixel A corresponding to the presence of the information signal is applied with the voltage of 2V exceeding the threshold voltage V _th1, and thus shifts to the first stable state. However, the pixel B corresponding to no information on the same scanning line is not changed in the second period t ₂
Since the applied voltage at V is V, it remains in the second stable state.

On the other hand, like the pixels C and D, the pixels on the non-selected scanning lines have an applied voltage of V or 0, and neither exceeds the threshold value, and the liquid crystal molecules in each of the pixels C and D have the signal state at the time of the previous scanning. That is, it retains the orientation of, that is, stores the signal of the previous screen.
Therefore, even if the number of scanning electrodes is increased, the duty ratio does not substantially change, and the contrast is not deteriorated and crosstalk does not occur at all. The voltage value and the value of the signal writing period T (t ₁ + t ₂ ) to each pixel are usually 3 V to 70 V, 0.1 μsec to 2 μ, depending on the liquid crystal material used and the thickness of the cell.
It is in the range of seconds.

When the liquid crystal display of FIG. 4A is used in the embodiment of FIG. 1, the scan drive circuit 44 supplies a scan drive signal to the scan electrodes 112 (see FIG. 4A (a)) of the display.

When the liquid crystal display is used in color, a color filter layer or a color polarizing plate is arranged in a mosaic pattern for each pixel and the transmittance of the three primary colors is controlled individually. 3 and the ability to display colors is also reduced. Since liquid crystal with ferroelectric constant can be driven at high speed, the display screen can be enlarged, and compared with conventional TN liquid crystal,
It is possible to display a higher definition image.

〔The invention's effect〕

As can be easily understood from the above description, according to the stereoscopic television device of the present invention, stereoscopic vision can be realized without an optical shutter, and thus without its opening / closing control system, and the signal storage function of the liquid crystal display device can be used. , The flicker of the observation screen is
If there is none or if there is, it will be extremely small.

[Brief description of drawings]

FIG. 1A is a block diagram of an embodiment of the device according to the present invention,
FIG. 1B is a diagram showing the arrangement of the polarizers of the respective pixels on the display surface, and FIG. 1C is a diagram showing the relationship between the polarizers of the pixels and the analyzer of the spectacles for the right eye and the left eye. FIG. 2 is a diagram showing a molecular alignment of a ferroelectric liquid crystal having a cairo smectic phase, FIG. 3 is a diagram showing an alignment of liquid crystal molecules when the liquid crystal of FIG. 2 is thinned, and FIG. 4A. 4 and FIG. 4B are explanatory views of a driving method and a driving state when the ferroelectric liquid crystal is driven in a matrix, FIG. 5 is a schematic explanatory view of the outer surface of a general matrix type display of liquid crystal, and FIG. It is explanatory drawing of a matrix drive system. FIG. 7 is a block diagram of the basic configuration of a stereoscopic television device. 12 …… Changeover switch, 14 …… VTR device, 20 …… Intermediate frequency amplification and AGC circuit, 22 …… Video detection circuit, 24 …… Audio circuit, 26 …… Speaker, 28 …… Video amplifier, 30 ……
A / D converter, 32 ... Line memory, 34 ... Synchronous separation circuit, 36 ... Horizontal oscillation circuit, 38 ... Vertical oscillation circuit, 40 ...
Timing circuit, 42 ... Shift register, 44 ... Scan drive circuit, 46 ... Liquid crystal display, 48 ... Modulation drive circuit, 201,202 ... Camera, 203 ... Mixer, 204 ... TV receiver, 205 ... … Shutter drive circuit, 206,207 …… Shutter

Claims (2)

[Claims] 1. Stereoscopic viewing is provided by providing polarizing right-eye and right-eye analyzing members orthogonal to each other and observing the left-eye image with the left eye and the right-eye image with the right eye through the analyzing members. A stereoscopic television device for realizing the above, wherein a liquid crystal display device having a signal storage function is used as a display device, and pixels of the liquid crystal display device are divided into alternating right-eye pixel columns and left-eye pixel columns, and right-eye pixels are provided. The column is provided with a polarized light polarizing member corresponding to the right eye analyzing member of the spectacles, the left eye pixel column is provided with a polarizing polarizing member corresponding to the left eye analyzing member of the spectacles, and the right eye image is provided in the right eye pixel column. A stereoscopic television device, which supplies a signal and supplies a left-eye video signal to the left-eye pixel column. 2. A stereoscopic television device according to claim 1, wherein the liquid crystal display device is made of a ferroelectric liquid crystal having a chiral smectic phase.