JP2000098966A - Display method using wobbling technology - Google Patents

Abstract

(57) [Summary] [PROBLEMS] A display method using a pixel arranged in a matrix to improve resolution, enable smoother video display corresponding to moving images, and further reduce flicker. provide. SOLUTION: In an image display method using display pixels arranged in a matrix, a video signal of a certain field is displayed using a wobbling (pixel shift) technique of shifting a display pixel in synchronization with a video signal. The wobbling technique is characterized in that a pixel 1 'for displaying a video signal of the next field is shifted by an interval between adjacent rows or columns of the pixel 1 and displayed with respect to the position of the pixel 1. The display method used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a liquid crystal, a plasma,
The present invention relates to an image display method using matrix-like pixels arranged at discrete display positions, such as EL (electroluminescence).

[0002]

2. Description of the Related Art In recent years, the spread of high-definition television broadcasting,
With the trend toward higher performance of computers and the like, the trend of higher definition of displays is rapidly increasing. However, a display device such as a liquid crystal, a plasma, and an EL has a discrete pixel arrangement of a mosaic shape, a dot shape, and the like.
When a line sequential scanning image is displayed by the C method or the like, there is a problem that a luminance signal which should be an analog signal is coarsely sampled and horizontal position information is lost.

When the display device cannot be mounted in the vertical direction by the number of scanning lines of the video signal, the resolution in the vertical direction is reduced in order to lose information of the scanning lines or to overwrite on the same pixel. . For example, an image of one frame in the NTSC system is formed by two fields each including an even-numbered scanning line and an odd-numbered scanning line, and has a frame frequency of 30 Hz (a field frequency of 60H).
z). When the image is driven by a TFT liquid crystal panel, at present, 525 scanning lines of the NTSC system cannot be mounted, and therefore, a method of writing an odd field and an even field in the same pixel is adopted. Therefore, the vertical resolution is lower than the original signal of the NTSC system.

Therefore, as shown in FIG. 10, the wobbling technique (pixel shifting) is employed to spatially shift the images of the odd field and the even field, thereby apparently doubling the number of pixels, thereby vertically increasing the number of pixels. Methods for improving the resolution have been proposed. In other words, if the pixel position of the even field screen is shifted to the area between the horizontal scanning lines (shift by １ ／ row) and the pixel position of the odd field screen is left on the horizontal scanning line, the vertical resolution is doubled. Become.

[0005] As such a wobbling element, it is known that a liquid crystal element (phase control element) as disclosed in, for example, JP-A-7-20432 is used. That is, this liquid crystal element is combined with a birefringent medium (optically anisotropic body) such as a quartz plate and arranged in an optical path of a display element or the like to be wobbled. The polarization plane is rotated by modulating the phase, and depending on the presence or absence of this rotation, the light emitted from the liquid crystal element is selectively shifted in a predetermined direction (wobbling direction) by the birefringence effect of the birefringent medium (the wobbling direction). FIG.
(A)).

FIG. 8A shows a case where the FLC extraordinary optical axis coincides with the polarization direction of the display element.
(B) shows that the FLC extraordinary optical axis is 45 degrees with the polarization direction of the display element.
This shows a case where the angle is in degrees.

FIGS. 8A and 8B schematically show an example of an optical device incorporating a wobbling element.

In this example, a liquid crystal display element (LCD) 2 is sequentially arranged in the same optical path along the traveling direction of light, and a ferroelectric liquid crystal element (FLC) as a phase modulation optical element (phase control element). 3 and a birefringent medium 4 made of a transparent substrate such as a quartz plate. here,
For easy understanding, each component is a liquid crystal display element LCD.
Each of the sections corresponding to one of the constituent display pixels 5 is shown, and the liquid crystal alignment film and the like are not shown (the same applies hereinafter).

The pixel 5 of the LCD 2 has a discrete pixel arrangement such as a mosaic as a whole, and the liquid crystal used is TN (twisted nematic) or STN.
(Super twisted nematic), SH (super homeotropic), and FLC. This LCD
2 is not shown, but as is well known, the panel itself has a polarizing plate, and the output light 6 has linearly polarized light.

Then, for this linearly polarized light 6, the above F
A picture element is shifted in a parallel direction or a vertical direction by a wobbling element (picture element shifting element) 7 composed of the LC 3 and the birefringent medium 4.

For this purpose, one extraordinary optical axis 8 of the FLC element 3 is arranged so as to be parallel or perpendicular to the polarization plane 9 of the display pixel 5, and furthermore, equivalently, a uniaxial optical axis (uniaxial optical axis). The projection component on the XY plane (incident side) of the extraordinary optical axis 10 of the transparent substrate 4 having high optical anisotropy) is arranged parallel (Y direction) or perpendicular (X direction) to the polarization plane 9. ing.

The liquid crystal used in the FLC element 3 is a liquid crystal capable of high-speed switching at a video rate, such as a chiral smectic liquid crystal, and the birefringent medium 4 can be a quartz plate. However, instead of FLC, an antiferroelectric liquid crystal (AFLC) or a smectic liquid crystal (for example, smectic A) exhibiting an electroclinic effect is also effective, and a birefringent element other than a quartz plate can of course be used.

Next, the wobbling operation of the display device will be schematically described.

First, as shown in FIG. 8A, when the switch state of the ferroelectric liquid crystal element 3 is state 1, the polarization plane 9 of the light 6 irradiated from the display element 2 side and the ferroelectric liquid crystal element 3 Since the extraordinary optical axis 8 is parallel, the transmitted light 11 is applied to the quartz plate 4 having birefringence while maintaining the polarization plane. Quartz plate 4
Then, since the extraordinary optical axis 10 of the crystal is included in the incident polarization plane,
Light polarized in the Y-axis direction is reflected on the extraordinary optical axis 10 of the quartz plate 4.
Is refracted in the direction of inclination, and becomes parallel to the optical axis when exiting again as an outgoing light 12 to the air layer, and the deviation of the incident light from the optical axis occurs in the Y direction.

On the other hand, when the switch state of the ferroelectric liquid crystal element 3 is state 2 as shown in FIG. 8B, the polarization plane 9 and the extraordinary optical axis 8 form an angle of about 45 degrees. The transmitted light 11 rotates in the direction of the extraordinary optical axis and changes in the ferroelectric liquid crystal element 3 as linearly polarized light (Y-axis direction) → elliptically polarized light → circularly polarized light → elliptically polarized light → linearly polarized light (X-axis direction). The surface is 90 from the initial state
The crystal plate 4 is rotated by degrees. In the quartz plate 4, since the extraordinary optical axis 10 of the crystal is not included in the incident polarization plane, the light 11 is not refracted, maintains the optical axis as it is, and emerges again as the outgoing light 12 to the air layer.

As described above, it is possible to shift the optical axis according to the switching state of the FLC 3, that is, the presence or absence of refraction by the quartz plate 4 in the state 1 and the state 2, and use the shift of the optical axis as an operation principle of the picture element shifting. it can.

[0017]

However, as the miniaturization technology advances day by day, if the display device has horizontal scanning lines equal to or more than the number of scanning lines of the video signal, the effect of improving the vertical resolution is obtained. And the horizontal resolution does not change at all.

Further, in a display method using pixels arranged in a matrix, there is a demand for a method that can display a moving image more smoothly and more smoothly.

There is also a need for a display method that makes flicker less noticeable.

[Object of the Invention] An object of the present invention is to provide a display method using pixels arranged in a matrix so as to improve resolution, enable smoother video display corresponding to moving images, and further reduce flicker. It is an object of the present invention to provide a display method for eliminating the display.

That is, an object of the present invention is to provide a display device having a vertical resolution which is sufficient for the number of scanning lines of a video signal, in which the shift amount for wobbling display pixels is set to the row interval in the pixel column direction. To improve the horizontal resolution.

Another object of the present invention is to form a one-field image on two display screens by using a frame memory and double-speed driving, thereby performing smoother image display corresponding to a moving image.

When the above-described display method based on wobbling is applied to a liquid crystal display device, in order to prevent a DC component from being applied to the liquid crystal, each time the display screen is switched, the polarity of the video signal is inverted and driving is performed. Voltage applied to
If different between the normal rotation side and the reverse rotation side, a luminance difference occurs between the wobbled fields, and for example, flicker (flicker) of 30 Hz becomes noticeable. Therefore, an object is to form a one-field image on two display screens, thereby doubling the flicker cycle (for example, 60 Hz) to make the flicker less noticeable.

[0024]

According to the present invention, there is provided a method for displaying an image using display pixels arranged in a matrix, wherein the display pixels are synchronized with a video signal. By using the wobbling technique of shifting, the position of the pixel displaying the video signal of a certain field is compared with the position of the pixel displaying the video signal of the next field by the distance between adjacent rows or columns of the pixel. An object of the present invention is to provide a display method using a wobbling technique characterized by shifting and displaying.

Also, using a screen scanning line of an interlaced signal, a signal for one video scanning line is written over two rows of pixels of the display device to display an odd field screen first, and then correspond to an even field. When an image is displayed, the display method shifts in the column direction by a row interval of pixels by wobbling, and is a display method using a wobbling technique.

Further, a signal corresponding to one video scanning line is written over two rows of pixels of the display device using a screen scanning line of an interlaced signal, so that an even field screen is displayed first, and then an odd field corresponding to an odd field is displayed. When an image is displayed, the display method shifts in the column direction by a row interval of pixels by wobbling, and is a display method using a wobbling technique.

Further, there is provided a display method using a wobbling technique, wherein the wobbling shifts in the row direction by a column interval of pixels.

Further, there is provided a display method using a wobbling technique, wherein an image of one field is formed on two display screens by using a frame memory and double-speed driving.

A display method using a wobbling technique is characterized in that a screen of an odd field α is combined with a screen of an wobbled odd field β to represent one odd field.

The display method according to claim 6, wherein the odd field is an even field.

Further, in the liquid crystal display device, when driving by inverting the polarity of the video signal every time the display screen is switched, the flicker cycle is reduced by forming the video of one field on two display screens. This is also a display method using a wobbling technique characterized in that the display is doubled.

The present invention also provides a display method using a wobbling technique, in which double-speed driving for wobbling twice during one frame is performed.

Further, the sampling of the screen scanning lines of the non-interlaced signal is sequentially allocated to the horizontal scanning lines of the liquid crystal display device, the display screen is set to the field α, and the sampling of the screen scanning lines is shifted by one. Wobbling by allocating a signal to a horizontal scanning line of the liquid crystal display device and wobbling the display screen as a field β, and combining the fields α and β to display an image of one field. It is also a display method using technology.

[Operation] According to the present invention, in a wobbling technique (pixel shifting) for shifting a display pixel in synchronization with a video signal, the position of a pixel displaying a video signal in a certain field is determined by the following. The horizontal resolution or the vertical resolution can be improved by shifting the pixels when displaying the video signal of the field by the distance between adjacent rows or columns.

In the display method by wobbling, the use of a frame memory and double-speed driving enables
By forming an image of one field on one display screen,
Smooth video display corresponding to moving images can be performed.

Further, in the case where the present invention is applied to a liquid crystal display device, the polarity of the video signal is inverted every time the display screen is switched to be driven.
Flicker can be suppressed.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] FIG. 1 is a schematic diagram for explaining a pixel display method according to the present embodiment, and shows a video signal having 525 horizontal scanning lines of the NTSC system on the left side. This video signal is displayed on the right side of a pixel 1 having a vertical pixel pitch of 10 μm and a horizontal pixel pitch of 20 μm.
FIG. 4 is a diagram showing a case where a display is performed by a liquid crystal display device having the following.

FIG. 9 shows such a liquid crystal display device.
FIG. 2 is a diagram illustrating the principle of configuration when a normally white TN liquid crystal display element is used.

In FIG. 9, the wobbling element is a combination of a ferroelectric liquid crystal element 3 and a birefringent medium 4. By controlling this element, a display pixel is apparently shifted in an arbitrary direction. be able to.

In the case of a normally white TN liquid crystal display element shown in FIG. 9, light from a light source is transmitted in a state where no electric field is applied to the TN liquid crystal. Here, the combination of the backlight 17-the polarizing plate 18-the TN liquid crystal 2-the polarizing plate 19 or the combination of the reflecting plate-the polarizing plate 18-the TN liquid crystal 2-the polarizing plate 19 is the same as the conventional TN liquid crystal TN liquid crystal display. 4 shows an element. Needless to say, the TN liquid crystal element 2 and the ferroelectric liquid crystal element 3 each have transparent electrodes disposed on both surfaces thereof.

In this case, as the electric field strength increases, T
The twist of the N liquid crystal 2 is released, light gradually leaks through the polarizing plate, and gradation display is realized, but any transmitted light becomes the same linearly polarized light by the polarizing plate 19 in front of the ferroelectric liquid crystal element 3. Therefore, picture element shifting can be performed according to the above-described operation principle.

In this embodiment, as shown in FIG. 1A, the pixel 1 of the liquid crystal display device has a sufficient number of horizontal scanning lines for 262 scanning lines in the odd field. Is written over two rows of pixels of the display device to display an odd field screen.

When an image corresponding to an even field is displayed as shown in FIG. 1 (b), wobbling causes a row interval P _V = 10 μm in the column direction (downward) as in the pixel 1 ′. ,shift.

As described above, by setting the shift amount of the wobbling in the column direction to the adjacent row interval Pv = 10 μm, the space between pixels is filled, and apparently, the horizontal pixel interval is P _H / 2 = 10 μm (FIG. 1)
(C)). In other words, the row resolution is doubled and the horizontal resolution is doubled. However, in FIG. 1, a delta arrangement is assumed for odd or even fields.

In the present embodiment, the case where wobbling is performed in the column direction has been described. However, the present invention can be similarly performed in the case where wobbling is performed while shifting in the row direction.
Apparently, the horizontal pixel interval P _H is １ ／, the column interval is narrowed, and the horizontal resolution is doubled.

FIG. 11 is a diagram showing a case where display pixels in an even field are shifted in the row direction by a column interval (FIG. 11B) and wobbled. As shown in FIG. Has doubled.

FIG. 12 is a diagram showing a case where the conventional example shown in FIG. 10 is shifted by one row as in the present invention, instead of the conventional half-row shift in the column direction.
The horizontal resolution is doubled.

[Embodiment 2] In Embodiment 1 or the conventional example, wobbling was performed when displaying an odd field and an even field. In Embodiment 2, however, as shown in FIG. By combining the screen and the screen of the wobbled odd (even) field β, one odd (even) field is represented. That is, one field is formed by two display screens.

FIG. 3 shows the timing of wobbling with the video signal. In the first embodiment or the conventional example, FIG.
As shown in (a), each time the video signal switches between the odd field and the even field, the wobbling is performed once in one frame.

On the other hand, as shown in FIG. 3B, in the second embodiment, wobbling is performed twice during one frame. This can be realized by using a frame memory and performing double-speed driving as compared with the conventional case.

According to the second embodiment, since a video signal of one field is expressed by two display screens, not only the resolution can be improved, but also a smooth image corresponding to a moving image can be obtained.

In the first and second embodiments, the interlaced signal of the NTSC system has been described, but the same holds true for a non-interlaced signal. FIG. 4 shows a case where a non-interlaced signal is displayed. First, a horizontal scanning line of the liquid crystal display device is sequentially assigned to a screen scanning line of a non-interlace signal, and the display screen is set as a field α (FIG. 4A). Next, signals are assigned to the scanning lines of the display device by shifting the sampling of the screen scanning lines by one, and wobbling is performed, and the display screen is set as a field β (FIG. 4B).

As a result, an image of one field can be displayed as a combination of the fields α and β. This image has twice the horizontal resolution as compared to the image without wobbling.

[Embodiment 3] In the present embodiment, when applied to a liquid crystal display device, the present invention relates to polarity inversion driving of video signals applied to pixels. Usually, when driving a liquid crystal display device, in order to prevent a DC component from being applied to the liquid crystal, the polarity of the video signal is inverted each time the display screen is switched to be driven.

FIG. 5A shows this operation.
The video signal is periodically rotated (for example, every field) forward and reverse around the potential _{VLC of the} counter electrode. FIG.
(B) is a view equivalently showing the state applied to the liquid crystal, and a monochrome gradation display can be performed by using the potential _{VLC of the} counter electrode by the potential difference of the video signal. At this time, the combined V _LC to the signal center, a forward side and a V _LC potential difference between the DC component applied to the liquid crystal by the equal potential difference of the reverse side and V _LC of the video signal is inverted drive I am trying to get rid of it.

Therefore, if the _VLC deviates from the signal center, the potential difference between the _VLC on the non-inverting side and the _VLC on the inverting side of the video signal differs, and a black-and-white gradation display difference, that is, a luminance difference occurs.

When this is represented by a wobbled screen, what is generally called field inversion is shown in FIG.
And (b). At this time, if the voltage applied to the pixel is different between the normal side and the reverse side due to a signal shift or the like, a luminance difference occurs between the wobbled fields, and the NTSC
In the case of the video signal of the system, as shown in FIG. 6C, the luminance change becomes noticeable as a flicker of 30 Hz.

Therefore, by forming an image of one field on two display screens at the timing described in the second embodiment, the polarities of the display pixels can be represented as shown in FIGS. 7 (a) and 7 (b). . At this time, the luminance change can be expressed as shown in FIG. 7C, and the period of flicker is doubled (60 Hz).
It becomes inconspicuous.

[0059]

As described above, according to the display method of the present invention, in the wobbling for shifting the display pixels in synchronization with the video signal, the position of the pixel displaying the video signal of a certain field is determined. The horizontal resolution or the vertical resolution can be doubled by shifting the pixels for displaying the video signal of the next field by the interval between adjacent rows or columns.

Further, in the above-described wobbling display method, by forming an image of one field on two display screens using a frame memory and double-speed driving, a smooth image display corresponding to a moving image can be performed. .

Further, when the present invention is applied to a liquid crystal display device, flicker can be suppressed by inverting the polarity of the video signal every time the display screen is switched, by inverting the double speed driving.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a pixel display method according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a pixel display method according to a second embodiment of the present invention.

FIG. 3 is a diagram illustrating timing of wobbling with a video signal.

FIG. 4 is a schematic diagram showing an embodiment of video display of a non-interlaced signal in the present invention.

FIG. 5 is a diagram illustrating polarity inversion of a video signal applied to a liquid crystal.

FIG. 6 is a diagram illustrating the polarity of a video signal applied to a pixel.

FIG. 7 is a diagram illustrating the polarity of a video signal applied to a pixel in double-speed driving.

FIG. 8 is a schematic diagram illustrating an example of a wobbling element.

FIG. 9 is a schematic diagram illustrating a configuration of a normally white TN liquid crystal display element.

FIG. 10 is a schematic view showing a conventional pixel display method.

FIG. 11 is a schematic diagram when shifting in the row direction in the first embodiment of the present invention.

FIG. 12 is a schematic diagram showing a case where the present invention is applied to FIG. 10 of a conventional example.

[Explanation of symbols]

 1 pixel 1 'pixel wobbled and shifted

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H093 NA07 NA11 NA33 NA43 NC29 ND10 ND20 NE06 NF05 NF19 5C006 AA11 AA22 AC24 AF34 AF44 AF47 BB11 BC11 BC16 FA00 5C080 AA05 AA06 AA10 BB05 CC03 DD07 EE19 EE29 GG01 JJ09 GG09 GG09

Claims (10)

[Claims] 1. A method of displaying an image using display pixels arranged in a matrix, comprising: a pixel displaying a video signal of a certain field using a wobbling technique of shifting a display pixel in synchronization with a video signal. A display method using a wobbling technique, wherein a pixel for displaying a video signal of the next field is shifted by an interval of a row or a column adjacent to the pixel with respect to the position of the pixel and displayed. 2. A screen scanning line of an interlaced signal is used to write a signal for one video scanning line over two rows of pixels of a display device to display an odd field screen first, and then correspond to an even field. 2. The display method using wobbling technology according to claim 1, wherein when displaying the image, the image is shifted by a row interval of pixels in a column direction by wobbling. 3. A screen scan line of an interlaced signal is used to write a signal corresponding to one video scan line over two rows of pixels of a display device to display an even field screen first, and then correspond to an odd field screen. 2. The display method using wobbling technology according to claim 1, wherein when displaying the image, the image is shifted by a row interval of pixels in a column direction by wobbling. 4. The display method using the wobbling technique according to claim 2, wherein the wobbling shifts in a row direction by a column interval of pixels. 5. The display method according to claim 1, wherein an image of said one field is formed on two display screens by using a frame memory and double-speed driving. 6. By combining the screen of the odd field α and the screen of the wobbled odd field β,
The display method according to claim 5, wherein the display method represents one odd field. 7. The display method according to claim 6, wherein the odd field is an even field. 8. In a liquid crystal display device, when driving by inverting the polarity of a video signal every time a display screen is switched, an image of one field is formed on two display screens, thereby reducing the flicker cycle to two. 6. The display method according to claim 5, wherein the display is doubled. 9. The display method using wobbling technology according to claim 5, wherein double-speed driving for wobbling twice during one frame is performed. 10. A screen scanning line sampling of a non-interlaced signal is sequentially assigned to a horizontal scanning line of a liquid crystal display device, a display screen is set as a field α, and then sampling of the screen scanning line is shifted by one. Wobbling by allocating a signal to a horizontal scanning line of the liquid crystal display device and wobbling the display screen as a field β, and combining the fields α and β to display an image of one field. Display method using technology.