JPH11259039A - Driving method of display device and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an interlace display and also to improve horizontal resolution by shifting a sampling timing at the time of performing a 1st and a 2nd field scannings by a time corresponding to a picture element shift amount caused by wobbling. SOLUTION: A frame of picture is formed (C) by scanning a 1st field without wobbling (A) and scanning a 2nd field with diagonal wobbling (B). In the vertical direction, the interlace display by the 1st field scanning and the 2nd field scanning is performed by vertical wobbling, and in the horizontal direction, different from the case of the vertical wobbling, the interlace display is performed by shifting the sampling timing (b) at the 2nd field scanning for displaying the same pixel by a time amount (phase) Δt corresponding to a horizontal pixel shift amount ΔLx caused by the wobbling to the 1st sampling timing (a).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a liquid crystal, a plasma,
The present invention relates to a method for driving a display device having a discrete fixed pixel array, such as EL (electroluminescence), and a display device.

[0002]

2. Description of the Related Art An electronic display device is an electronic device that transmits various information from various electronic devices to humans through visual perception, or an electronic tool for information exchange between humans through electronic devices and visual perception. Can be
2. Description of the Related Art Electronic display devices in the information society are widely used in various application fields regardless of the industrial field or the consumer field, and their role is extremely important.

In recent years, liquid crystal displays, plasma displays, EL displays and the like have been actively researched and developed as electronic display devices replacing CRTs. For example, attempts have been made to realize a large flat display of 40 to 60 inches, such as a liquid crystal projector or a plasma display, in the HD (high definition) system.

[0004]

However, a display device (display device) having a discrete fixed pixel array and a line-sequential driving system, such as a liquid crystal, a plasma, an EL, etc., is an NTSC system or an HD ( In particular, when performing interlaced (interlaced scanning) display such as in high definition
There is a problem that it cannot simply cope with interlaced scanning. On the other hand, countermeasures such as providing a new interlaced sequential circuit in the display device itself or converting the video signal to non-interlace using a memory and displaying the image signal are taken. Must configure complex systems.

In this case, the number of pixels of the display device, particularly the number of vertical pixels, is required for the number of effective scanning lines of the video signal. If the number of pixels of the display device does not reach the number of effective scanning lines, an odd number is required. A field (first field) and an even field (second field) are written to the same pixel, or writing is performed by appropriately thinning out video signals. That is, the vertical resolution in the display device is reduced, and the image quality is inferior to the original video signal.

On the other hand, in a display device having a display element composed of discrete fixed pixels, a display pixel shifting technique (wobbling technique) is used as means for improving the resolution in the vertical direction using the same pixel. Known (JP-A-7-64046, JP-A-7-1042)
No. 78, etc.).

In this wobbling technique, one field image is changed to another field image by switching the optical axis of the first field scan and the optical axis of the second field scan with the phase modulation optical element and the birefringent medium. This is a method of displaying at a different position.

However, in the methods described in JP-A-7-64046 and JP-A-7-104278, the vertical optical axis shift, that is, the improvement of the vertical resolution, is performed in the first field and the second field. This can be achieved by using a signal synchronized with the interlace, but in the horizontal direction, since the resolution of fixed pixels is limited by the number of pixels, even if the bandwidth of the video signal is wide, it can be displayed as it is. The horizontal resolution cannot be increased beyond the number of pixels.

That is, in a display device having discrete fixed pixels such as a liquid crystal panel, the resolution in the horizontal direction is limited by sampling. Therefore, even if an interlaced signal is displayed as it is, the same image is shifted in the horizontal direction. Display, and there is a limit to improving the resolution.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and has as its object to provide a display device having a display element with a fixed pixel array, capable of interlaced display, and in particular, having a horizontal resolution. It is an object of the present invention to provide a display device driving method and a display device which realize improvement.

[0011]

As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that a display element having discrete fixed pixels and an interlaced display using a wobbling element are used. In order to realize high resolution in the above, the sampling timing at the time of scanning the first field (for example, an odd field) and the sampling timing at the time of scanning the second field (for example, an even field) correspond to the pixel shift amount caused by wobbling. It has been found that by applying a drive signal to the display element at a time shifted by a certain time, interlaced display becomes possible and high resolution can be realized.

That is, according to the present invention, a display element having discrete fixed pixels driven by a signal obtained by sampling a video signal for each field, and wobbling occurs in a light beam emitted from the display element. In driving the display device including the wobbling element, the sampling timing at the time of the first field scanning and the sampling timing at the time of the second field scanning are shifted by a time corresponding to a pixel shift amount caused by the wobbling by the wobbling element. The present invention also relates to a method of driving a display device for applying a drive signal to the display element (hereinafter, referred to as a driving method of the present invention).

According to the driving method of the present invention, when a display device including the display element and the wobbling element is driven, the sampling timing at the time of scanning the first field and the sampling timing at the time of scanning the second field are determined by the following. Since the drive signal is applied to the display element at a time corresponding to the amount of pixel shift caused by wobbling by the wobbling element (that is, the time required for wobbling), interlaced display or the like compatible with the NTSC system or the HD system is high. It can be realized with resolution.

In particular, according to the driving method of the present invention, the sampling timing of the first field scanning and the sampling timing of the second field scanning are merely shifted by a predetermined time (phase), and the interlacing with high resolution in the horizontal direction is performed. Since the display can be realized, it is possible to support the NTSC system and the HD system without making a change in the device configuration such as providing a sequential circuit corresponding to an interlace. Further, since a pixel shift in an oblique direction (hereinafter, sometimes referred to as oblique wobbling) becomes possible, further higher resolution can be realized.

According to the present invention, a display device having discrete fixed pixels driven by a signal obtained by sampling a video signal for each field is provided as a display device capable of realizing the driving method of the present invention; A wobbling element that causes wobbling in a light beam emitted from the display element, and a sampling timing at the time of scanning the first field and a sampling timing at the time of scanning the second field.
A timing generating circuit that shifts by a time corresponding to a pixel shift amount caused by wobbling by the wobbling element, and a drive circuit that drives the display element and the wobbling element for each field by a timing signal of the timing generating circuit. A display device (hereinafter, referred to as a display device of the present invention) is provided.

According to the display device of the present invention, a display element having discrete fixed pixels such as a liquid crystal, a plasma, and an EL, a wobbling element that causes wobbling in a light beam emitted from the display element, and a first field A timing generating circuit for shifting the sampling timing at the time of scanning and the sampling timing at the time of scanning the second field by a time (phase) corresponding to a pixel shift amount caused by wobbling by the wobbling element, and a timing signal of the timing generating circuit. Since a driving circuit (driver circuit) for driving the display element and the wobbling element is provided for each field, the sampling timing in the timing generation circuit can be changed without changing the substantial configuration of the display device. Just shift by the predetermined time, NTS Interlaced display or the like corresponding to the system or HD system allows, and high resolution is realized.

[0017]

In the driving method and the display device according to the present invention, the time (Δ) corresponding to the pixel shift amount is used.
Preferably, t) is a time corresponding to the horizontal pixel shift amount (ΔLx) caused by the wobbling. ΔLx and Δt may be considered to be substantially proportional.

Further, it is desirable that the wobbling is caused by the time of the synchronizing signal of each field scan, and the vertical pixel shift is performed simultaneously with the horizontal pixel shift (ie, oblique wobbling is performed). .

Here, the driving method of the display device according to the present invention will be described with reference to FIGS. FIG. 9 shows a conventional method of processing an interlace signal.

FIG. 9 shows an interlaced display example (A) of an HD signal (especially a high-definition signal), and a display example of an interlaced signal displayed on a current liquid crystal display element (hereinafter, may be referred to as an LCD). 3B shows an LCD display example (C) when the vertical wobbling technology is used.

Recently, due to the high resolution technology of the liquid crystal panel, a panel capable of displaying all the scanning lines if the vertical resolution (about 480 lines) of the NTSC signal is used is a small size liquid crystal panel suitable for a projector or the like. However, since a device corresponding to a high-resolution signal such as an HD signal is complicated and expensive, the current LCD has a configuration shown in FIG.
The display as shown in FIG.

First, as shown in FIG. 9A, an interlaced signal such as an HD signal is used to scan an image (A-D) at the time of scanning a first field (for example, an odd field).
1), second field (eg, even field: even f)
ield) One frame image (A-3) composed of two field images of the image (A-2) at the time of scanning,
Visually, one frame is constituted by the interlace effect.

However, as shown in FIG. 9B, in the current LCD display, the image (B
-1), the image (B-2) at the time of the second field scanning is displayed on the same pixel (B-3), and both the resolution in the vertical direction and the resolution in the horizontal direction are greatly inferior.

The wobbling technique described above is known as a method for correctly interlacing the LCD display in the vertical direction. This is because the pixel shift is performed based on the above-described vertical optical path shift (vertical wobbling) while the LCD pixel remains the same as in the case of FIG.
As shown in (C), the image (C
-1) and an image (C-2) at the time of the second field scanning which is shifted by ΔLy in the vertical direction with respect to this image to perform interlaced display, and a one-frame image (C-3)
It constitutes.

FIG. 1 shows a two-dimensional optical path shift (oblique wobbling) based on the driving method of the present invention. This is, as shown in FIG.
Perform the first field scan without wobbling, and
As shown in FIG. 1B, this is an example of the case where the one-frame image shown in FIG. 1C is formed by obliquely wobbling the second field scan.

That is, in the oblique wobbling display based on the driving method of the present invention, in the vertical direction, interlaced display by the first field scan and the second field scan is performed by the above-described vertical wobbling, and in the horizontal direction, the vertical wobbling is performed. The sampling timing (b) at the time of scanning the second field displayed on the same pixel is different from the sampling timing (a) at the time of scanning the first field, and corresponds to the horizontal pixel shift ΔLx due to wobbling. Time (phase) minutes Δt
It is done by shifting only.

FIG. 2 shows the correspondence between sampling timings for displaying video signals by interlaced display on display elements having fixed pixels and display images.
It is assumed that the video signal (horizontal period) does not change in the vertical direction and has a gradation difference only in the horizontal direction. Also, Δ
t indicates a pixel shift amount (time) required for wobbling, and ΔLx indicates a horizontal pixel shift amount due to wobbling.

Here, as shown in FIG. 1, the video signal (horizontal period) includes a first (odd) field sampling timing (a) having a phase difference Δt corresponding to the horizontal pixel shift amount ΔLx, Each is sampled at the second (even) field sampling timing (b).

At this time, the first field signal (c) is
At the time of the first field scanning, display is performed on the display element 1 having fixed pixels. At this time, field information (e) is given to the wobbling element so that the optical path shift is not performed, and the display image 2 of the first field is formed. .

On the other hand, at the time of the second field scanning, the sampled second field signal (d) is displayed on the display element 1 to form a display image 3 of the second field. By performing the optical path shift (wobbling), a pixel shift in an oblique direction is performed. Reference numeral 5 denotes a display image (frame) with such an oblique shift. Reference numeral 4 indicates a display image (frame) without oblique displacement.

At this time, a display image (frame) 5 having a display image 2 of the first field and a display image 3 of the second field, which is obliquely displaced, has the original number of pixels of the fixed pixel display element 1 in the horizontal direction. A high-frequency signal component that cannot be displayed can be reproduced, and the pixel shift amount in the horizontal direction (pixel shift amount or optical path shift amount: the same applies hereinafter) ΔL
The sampling is performed at different sampling points by the first field sampling signal and the second field sampling signal having the phase difference (Δt) corresponding to x, so that diagonal wobbling becomes possible and the horizontal resolution ( Further, the resolution in the vertical direction is improved. In addition,
Numeral 6 is a switch for switching between the first field and the second field, which is schematically shown.

Next, in the driving method and the display device according to the present invention, it is preferable that the pixel shift amount is an amount that minimizes the overlap between the fixed pixel and the pixel shifted by the wobbling.

More specifically, as shown in FIG. 3, in a display element having discrete fixed pixels D _1-1 , D _1-2 , D _2-1 and D _2-2 , the pixel D _1-1 Let D _1-1 ′ be the pixel due to wobbling, ΔLy be the vertical pixel shift amount, and ΔLx be the horizontal pixel shift amount. These pixel shift amounts satisfy the following equations A and B: It is desirable. Min (Lpy−Dy, Dy / 2) ≦ ΔLy ≦ Max (Dy, Lpy−Dy / 2) Expression A and Min (Lpx−Dx, Dx / 2) ≦ ΔLx ≦ Max (Dx, Lpx−Dx / 2) ) Formula B [However, in the formulas A and B, Lpy is the vertical pitch length of the fixed pixel, Lpx is the horizontal pitch length of the fixed pixel, Dy is the aperture of the fixed pixel in the vertical direction, and Dx is the fixed size. The horizontal aperture of the pixel, Min (a, b), M
ax (a, b) is a function that gives a small value and a large value of a and b, respectively. ]

In the driving method and the display device according to the present invention, the wobbling element includes a phase modulation optical element such as a ferroelectric liquid crystal element and an anisotropic crystal (especially quartz).
An optical element composed of the above birefringent medium.

The wobbling element is, for example, a phase modulation optical element (FL) which is sequentially arranged on the optical axis of the light beam emitted from the display element 10 as shown by 11a in FIG.
C: ferroelectric liquid crystal) 12 and the first birefringent medium (quartz)
13, a half-wave plate (λ / 2 plate) 14, and a second birefringent medium (quartz) 15. With such an element, when one field scan is performed, 1 /
The two-wavelength plate 14 rotates the polarization plane of the light beam (c) passing through the first birefringent medium 13 by 90 degrees and guides it to the second birefringent medium 15, and the first birefringent medium 13 or It is desirable that the pixel shift in the horizontal direction and the pixel shift in the vertical direction are independently performed in the two birefringent media 15.

Here, the principle of wobbling will be described with reference to FIG.

In FIG. 4, a light beam from a light source not shown is a polysilicon TFT-liquid crystal panel (p-Si-TFT).
-LCD) and the like, the gradation is displayed by the display element 10, and the light beam emitted from the display element 10 is linearly polarized light, which is not shown, but is stuck or placed before and after the liquid crystal panel. It is determined by the direction of the crossed Nicols of the polarizing plate.

However, FIG. 4 shows an example in which a light beam polarized in the vertical direction (that is, having a plane of polarization in the Y-axis direction) is emitted. This is an example in which wobbling is performed during the first field scan (A) and wobbling is not performed during the second field scan (B).

First, as shown in FIG. 4A, at the time of scanning the first field, the light beam (a) emitted from the display element 10 is transmitted to the phase modulation optical element 12 made of, for example, FLC (ferroelectric liquid crystal element). Without being subjected to phase modulation, the polarization plane is kept as it is, and enters the first birefringent medium 13 made of, for example, a quartz plate.

At this time, since the polarization plane of the light beam (b) incident on the birefringent medium 13 includes the extraordinary optical axis of the first birefringent medium 13, the light beam (b) is polarized in the Y-axis direction. b) is refracted in the direction in which the extraordinary optical axis of the birefringent medium 13 is inclined (Y-axis direction shift). The shift amount at this time is ΔLy.

The light beam (c) shifted (optical axis changed) in the Y-axis direction by the first birefringent medium 13 is, for example, a half-wave plate (a half-wave plate or a λ / 2 plate). ), The polarization plane is rotated by 90 degrees, and is incident on a second birefringent medium 15 made of, for example, a quartz plate.

Next, the light beam (d) incident on the second birefringent medium 15 is transmitted in the X-axis direction because the birefringent medium 15 is arranged so as to include the extraordinary optical axis in the X-axis direction. (Light beam (e)). In addition,
The shift amount at this time is ΔLx.

As described above, at the time of the first field scanning (A), a pixel shift (ie, oblique wobbling) is finally performed in both the X-axis direction and the Y-axis direction.

On the other hand, as shown in FIG. 4B, during the scanning of the second field, the light beam (a) similarly emitted from the display element 10 is vertically modulated by the phase modulation optical element 12. The polarization plane, which has been rotated in the direction, is rotated by 90 degrees to become a horizontal direction and is incident on the first birefringent medium 13. Since no axis is included, the birefringent medium 13
Is emitted without refraction (that is, without pixel shift or optical axis change).

The light beam (g) is, for example, 1
The light beam (h) whose polarization plane is rotated by 90 degrees is incident on the second birefringent medium 15 in the phase modulation optical element 14 composed of a half-wave plate. Also at this time, since the incident light beam (h) has a polarization plane not including the extraordinary optical axis of the second birefringent medium 15, the light beam (h) is emitted as it is as the light beam (i) without any pixel shift (optical axis change). I do.

As described above, at the time of scanning the second field (B)
Is not pixel shifted (wobbled).

The display element (fixed pixel display panel) 1
The sampling timing of 0 needs to correspond to the pixel shift amount in the horizontal direction, and the vertical direction is an amount determined by the interlace signal and the pixel pitch. Thus, by using two birefringent media, It is particularly desirable to control the shift amount independently in the X-axis direction and the Y-axis direction. This also makes it possible to use the wobbling in the horizontal direction and the wobbling in the vertical direction independently according to the video signal standard and the like.

Although the pixels were shifted in the horizontal direction and the vertical direction separately using the two birefringent media, the linearly polarized light emitted from the liquid crystal panel was obliquely oriented in the crossed Nicols direction of the polarizing plate. The same pixel shift may be performed using one quartz plate by rotating the direction of the extraordinary optical axis of the quartz plate in advance in accordance with the direction.

That is, the wobbling element is constituted by a phase modulation optical element and a birefringent medium which are sequentially arranged, and the polarization plane of the light beam emitted from the display element is inclined. Thus, the optical axis may be shifted in an oblique direction.

Specifically, as shown in FIG. 5, the light beam emitted from the display element 10 is a light beam (a) having an obliquely polarized plane (this is disposed before and after the display element 10). This can be realized by the orientation of the polarizing plate.), And the wobbling element 11b is sequentially arranged on the optical axis of the light beam (a) emitted from the display element 10.
And the birefringent medium 13, the first
At the time of field scanning, as shown in FIG. 5A, the light beam (a) having a plane of polarization in the oblique direction and emitted from the display element 10 passes through the phase modulation optical element 12 without rotating the plane of polarization. Then, the optical axis of the light beam (b) is shifted in one direction (oblique direction) in the birefringent medium 13 and emitted as a light beam (c). On the other hand, at the time of the second field scan, as shown in FIG. 5B, the polarization plane of the light beam (a) having the polarization plane in the oblique direction emitted from the display element 10 is rotated by 90 degrees by the phase modulation optical element 12. Then, in the birefringent medium 13, the light beam (d) is emitted as the light beam (e) from the wobbling element 11b without shifting the optical axis. Is shifted diagonally between the first field scan and the second field scan.

Alternatively, the wobbling element is composed of a phase modulation optical element and a birefringent medium sequentially arranged on the optical axis of the light beam emitted from the display element 10, and emits from the display element. A half-wave plate for adjusting the phase of the light beam is arranged on the optical axis of the light beam, and the polarization plane of the light beam emitted from the display element is inclined. May be configured to be shifted in an oblique direction.

Specifically, as shown in FIG. 6, a half-wave plate 1 is provided between the display element 10 and the wobbling element 11b.
4 during the first field scan, as shown in FIG. 6A, the display element 10
The polarization plane of the light beam (a) emitted from the substrate is rotated by 90 degrees, and then the light beam (b) having an oblique polarization plane emitted from the half-wave plate 14 is
At 2, the polarization plane passes without being rotated, and further, at the birefringent medium 15, the optical axis of the light beam (c) is shifted in one direction (oblique direction) and emitted as a light beam (d). I do.
On the other hand, at the time of the second field scan, as shown in FIG. 6B, the polarization plane of the light beam (a) emitted from the display element 10 is rotated by 90 degrees in the half-wave plate (λ / 2 plate) 14. Then, in the phase modulation optical element 12, the light beam (e) having an oblique polarization plane emitted from the half-wave plate 14 has its polarization plane not rotated. Thus, the light beam (f) does not shift the optical axis,
Since the light beam is emitted as the light beam (g), the optical axis of the light beam emitted from the display element 10 is shifted obliquely between the first field scan and the second field scan.

Further, the wobbling element is constituted by a phase modulation optical element, a first birefringent medium and a second birefringent medium which are sequentially arranged. The second birefringent medium may be configured to perform the vertical pixel shift and the horizontal pixel shift independently.

More specifically, as shown in FIG. 7, a wobbling element 11c includes a phase modulation optical element 12 sequentially arranged on an optical axis of a light beam emitted from the display element 10, and a first birefringent medium. 13 and the second birefringent medium 15, when scanning the first field, FIG.
As shown in (A), the light beam (a) emitted from the display element 10 passes through the phase modulation optical element 12 without rotating its polarization plane, and then passes through the first birefringent medium 13. When the optical axis of the light beam (b) is shifted in one direction (Y-axis direction), and the optical axis of the light beam (c) passes through the second birefringent medium 15 without being shifted, The beam (d) is shifted in the Y-axis direction with respect to the light beam (a). On the other hand, during the second field scan, FIG.
As shown in (B), the polarization plane of the light beam (a) emitted from the display element 10 is rotated by the phase modulation optical element 12, and then the light beam (e) is emitted by the first birefringent medium 13. ) Passes through without being shifted, but in the second birefringent medium 15, the light beam (f) is
(In the axial direction), and emits as a light beam (g). Therefore, in the pixel A observed in the first field scanning and the pixel B observed in the second field scanning, each pixel is shifted in an oblique direction. Will be.

Further, the driving method and the display device of the present invention
It is desirable to apply to a projector device (especially a liquid crystal projector device). In this case, it is preferable that a 波長 wavelength plate is disposed on the optical axis of the light beam and at a stage subsequent to the wobbling element. The arrangement of the 波長 wavelength plate after the wobbling element is particularly effective in reducing flicker (brightness flicker) in the rear projector apparatus according to the present invention as shown in FIG.

Next, an example of a preferred embodiment according to the present invention will be described with reference to FIG.

The projector device shown in FIG. 8 is a device comprising an operation circuit system 21, a light source system 31, and a projection system 41 including a wobbling element 42. First, the light source system 31 and the projection system 41 of the projector device will be described. The wobbling element 42 in FIG. 8 substantially corresponds to the wobbling element 11a in FIG.

This projector is a three-panel type liquid crystal projector, in which a light source system 31 is provided with a lamp 32 as a light source, and a dichroic mirror 37a and an optical system for separating light into three primary colors. 3
7b, mirrors 36a, 36b and 36c, and an optical system including a cross prism 38, and as display elements, three liquid crystal panels corresponding to red (R), green (G), and blue (B), respectively. For example, polysilicon-TFT
(Thin film transistor) Liquid crystal panel: Hereinafter, p-Si
Sometimes referred to as a TFT liquid crystal panel. ], An optical system consisting of 35, 34 and 33.

That is, the light beam emitted from the lamp 32 is converted by the dichroic mirrors 37a and 37b into R beams.
The liquid crystal panel 3 is sequentially separated into three primary colors of GB, and is mirrored by mirrors 36a, 36b and 36c.
5, 34 and 33.

In the projection system 41, the wobbling element 42 uses an FLC (ferroelectric liquid crystal) 43 as a phase modulation optical element.
Quartz plates 44 and 46 are used as a birefringent medium.

Further, the cross prism 38 of the light source system 31
The light beam emitted from the optical system passes through a wobbling element 42 in the projection system 41 and is further subjected to a λ / 4 plate (a 波長 wavelength plate).
The light is incident on a projection lens 48 via 47 and is projected on a screen 49 at a predetermined projection size.

The liquid crystal panels 35, 34 and 33
Before and after (not shown), polarizing plates are arranged in crossed Nicols with each other. The liquid crystal panel displays an image with a gradation according to the image signal. At this time, the light beam emitted from the liquid crystal is linearly polarized by the polarizing plate, as is well known. At this time, the liquid crystal panel and the polarizing plate are arranged such that the light beams of the three primary colors have the same direction of linearly polarized light. The emitted light beam is synthesized by the cross prism 38 and enters the FLC element 43. The FLC element 43 functions to switch the direction of the polarization plane of the light beam between the parallel direction and the orthogonal direction in synchronization with the interlace signal with respect to the optical axis.

The next quartz plates 44 and 46 are
Since the direction of the extraordinary optical axis is placed in the parallel direction and the orthogonal direction with respect to the direction of the optical axis of the light beam emitted from
Pixel shifting is performed according to the switch state of the FLC element 43.

In this example, pixel shifting (wobbling) is performed so that pixels are shifted vertically and horizontally by the quartz plate 44 and the quartz plate 46, respectively. At this time, the light beam emitted from the wobbling element 42 remains vertical polarized light and horizontal polarized light switched for each of the first field and the second field by the FLC element 43 which is a phase modulation optical element.

Since the screen 49 has a luminance gain difference due to polarization, the screen 49 has a luminance difference for each field, which may be detected as flicker.
Therefore, after the wobbling element 42, the 波長 wavelength plate 4
Arranging 7 plays a role of eliminating linearly polarized light and eliminating a gain difference due to polarization of the screen 49 or the like to prevent flicker. Then, the image shifted in pixels for each field is projected on the screen 49 with high precision via the projection lens 48.

Next, the transmission path of the drive signal in FIG. 8 will be described.

The video signal (d) output from the video signal generation circuit 24 is guided to the LCD driver 25, where
The video signals (f), (g), and (h) input to the liquid crystal panels 35, 34, and 33 correspond to the horizontal pixel shift amount ΔL.
The first field sampling timing (b) generated by the timing generation circuit 23 according to the synchronization signal (a) generated by the synchronization signal generation circuit 22 and the second field sampling timing (b) so that the phase Δt differs by an amount corresponding to x. Depending on the field sampling timing (c), sampling is performed at different timings for each field.

That is, the timing generation circuit 23 sets the sampling timing for the first field scanning and the sampling timing for the second field scanning to a time (phase) corresponding to the pixel shift amount caused by wobbling.
This is a signal generation circuit that can be shifted by an amount. Also,
The LCD driver 25 and the FLC driver 26 use the timing signal (field information) (e) of the timing generation circuit 23 to drive the liquid crystal panels 35, 34, and 33 and the FLC element 43 for each field. It is.

As a result, the image displayed on the liquid crystal panel displays a signal shifted by the pixel shift ΔLx in the horizontal direction for each field, and the FLC driver 25 outputs the synchronization signal (i) synchronized with the field information (e). ) By FL
Since the C element 43 is driven, the synthesized image has an increased pixel density on the frame.

As described above, in this embodiment, interlaced display compatible with the NTSC system or the HD system can be performed without substantially changing the device configuration such as the fixed pixel arrangement of the display elements. In addition, it is possible to improve the resolution in both the horizontal and vertical directions by using a display element having a fixed pixel array.

In the DTV (digital TV) standard to be implemented in the future, interlaced and non-interlaced (progressive) signals of various resolutions will be established. Moreover, there is a possibility that it is required to handle all signals. In order to display such a signal on a fixed pixel panel, the number of pixels must be converted using the signal. However, as described above, the image quality deteriorates. Even in such a case, according to the present invention, for example, in the case of a progressive signal, it is possible to improve the horizontal resolution without performing interlacing by performing only the horizontal direction without wobbling in the vertical direction. .

Further, when performing interlaced display, writing can be performed at a normal video signal speed, and since it is not necessary to perform writing at double speed, there is no need to increase the frequency band of the signal system. There is no need for video signal memory or the like.

Further, by using two or more birefringent media for optical path shift (wobbling), it becomes possible to independently adjust the optical path shift amounts (ΔLy, ΔLx) in the vertical and horizontal directions. Further, it is easy to set the pixel shift amount optimized for the shape of the opening of the pixel of the display element. Note that the opening of the pixel of the display element here is
For example, a portion defined by a vertical diameter Dy and a horizontal diameter Dx of the pixel shown in FIG. 3 is shown.

When three wobbling elements are used for three display elements, the vertical direction and the
It is possible to adjust the optical path shift amount in the horizontal direction,
Adjustment according to chromatic aberration and the like is also possible.

Further, by disposing a quarter-wave plate between the wobbling element and the screen, flicker due to wobbling can be improved.

Although the present invention has been described with reference to the embodiment, the present invention is not limited to this embodiment.

For example, here, an optical system in which three plates are used and synthesized by the cross prism 38 and then wobbled is described as an example. However, FLC elements are disposed immediately after each display element, and three FLC elements are separately wobbled. May be performed. At this time, three FLC elements and a quartz plate may be used in a pair, or only three FLC elements may be combined and combined with a cross prism or the like, and then one quartz plate may be arranged.

Further, a single-panel display element in which pixels of each color are arranged in a matrix is used, and one pixel is placed between the projection lens and the display element.
Wobbling elements may be arranged. In particular, in the case of a single-plate display element, if it has the same aperture ratio as the three-plate,
Because the three primary colors are displayed on one sheet, the resolution of the image itself is 3
Since the resolution is reduced by a factor of 1, the resolution improvement effect of this method is great. Here, the aperture ratio is, for example, the vertical diameter Dy and the horizontal diameter of the pixel with respect to the area of the portion defined by the vertical pitch length Lpy and the horizontal pitch length Lpx of the pixel shown in FIG. The ratio of the area of the portion defined by Dx is shown.

In the present embodiment, a p-Si TFT LCD is used as a display element. However, if a pixel has a discrete pixel array, sampling is always performed. A similar improvement in resolution can be expected even if a device is used. That is, besides the liquid crystal panel,
An EL display, a plasma display, or the like can be used as appropriate.

Further, wobbling was performed in the first field or the second field. However, wobbling based on the driving method of the present invention may be performed for each pixel at the time of scanning each field, or may be performed for each pixel block. Good.

[0081]

According to the driving method of the present invention, a display element having discrete fixed pixels driven by a signal obtained by sampling a video signal for each field, and light emitted from the display element When driving a display device including a wobbling element that causes wobbling in a beam, the sampling timing at the time of scanning the first field and the sampling timing at the time of scanning the second field correspond to the pixel shift amount caused by the wobbling by the wobbling element. Since the drive signal is applied to the display element at a time shifted by a predetermined time, an interlaced display corresponding to the NTSC system or the HD system can be performed.
In addition, high resolution can be realized.

According to the display device of the present invention, a display element having discrete fixed pixels driven by a signal obtained by sampling a video signal for each field; a light beam emitted from the display element A wobbling element that causes wobbling of the wobbling element; and a timing generation circuit that shifts the sampling timing at the time of the first field scanning and the sampling timing at the time of the second field scanning by a time corresponding to a pixel shift amount caused by the wobbling by the wobbling element. A driving circuit for driving the display element and the wobbling element for each field according to the timing signal of the timing generation circuit; therefore, the NTSC can be performed without substantially changing the configuration of the display device. Table for HD and HD formats It allows, and can achieve high resolution.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an oblique wobbling processing method based on a two-dimensional optical path shift according to the present invention.

FIG. 2 is a schematic diagram showing a correspondence between a sampling timing for displaying an interlaced video signal on a fixed pixel display element and a display image.

FIG. 3 is a schematic diagram of a display element having fixed pixels.

FIG. 4 is a schematic view of a wobbling element according to the present invention.

FIG. 5 is a schematic view of another wobbling element.

FIG. 6 is a schematic view of another wobbling element.

FIG. 7 is a schematic view of another wobbling element.

FIG. 8 is a schematic diagram of the same projector device.

FIG. 9 is a schematic diagram illustrating a conventional method of processing an interlaced signal.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Display element which has a fixed pixel, 2 ... Display image of 1st field, 3 ... Display image of 2nd field, 4 ... Display image (frame) without pixel shift, 5 ... Display image with shift of oblique pixel (frame) ), 6 switches, 10 display elements (polysilicon TFT-LCD), 11a, 11
b, 11c: wobbling element, 12: phase modulation optical element (FLC element), 13: first birefringent medium, 14: 1
/ 2 wavelength plate (λ / 2 plate), 15 second birefringent medium, 2
DESCRIPTION OF SYMBOLS 1 ... Operation circuit system, 22 ... Synchronous signal generation circuit, 23 ... Timing signal generation circuit, 24 ... Video signal generation circuit, 25 ...
LCD driver, 26 FLC driver, 31 light source system, 32 lamp, 33 liquid crystal panel (B), 34 liquid crystal panel (G), 35 liquid crystal panel (R), 36a, 3
6b, 36c: mirror, 37a, 37b: dichroic mirror, 38: cross prism, 41: projection system, 42
... Wobbling element, 43 ... FLC element, 44, 46 ...
Quartz plate, 47 λ / 4 plate, 48 Projection lens, 49 Screen

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G09G 3/36 G09G 3/36 H04N 5/66 H04N 5/66 B

Claims (24)

[Claims] 1. A display element having discrete fixed pixels driven by a signal obtained by sampling a video signal for each field, and a wobbling element for causing wobbling in a light beam emitted from the display element. In driving the display device, the sampling timing at the time of the first field scan and the second
A method of driving a display device, wherein a sampling timing at the time of field scanning is shifted by a time corresponding to a pixel shift amount caused by wobbling by the wobbling element, and a driving signal is applied to the display element. 2. The method according to claim 1, wherein the time corresponding to the pixel shift amount is a time corresponding to a horizontal pixel shift amount caused by the wobbling. 3. The method according to claim 1, wherein the wobbling is caused by the time of the synchronization signal of each field scan, and the vertical pixel shift is performed simultaneously with the horizontal pixel shift.
3. The method for driving a display device according to item 1. 4. The method according to claim 1, wherein the pixel shift amount is an amount that minimizes the overlap between the fixed pixel and the pixel shifted by the wobbling. 5. The pixel shift amount in the vertical direction is ΔLy,
5. The method according to claim 4, wherein, when the pixel shift amount in the horizontal direction is ΔLx, the pixel shift amounts satisfy the following Expressions A and B. 6. Min (Lpy−Dy, Dy / 2) ≦ ΔLy ≦ Max (Dy, Lpy−Dy / 2) Expression A and Min (Lpx−Dx, Dx / 2) ≦ ΔLx ≦ Max (Dx, Lpx−Dx) / 2) ··· Formula B [wherein, in Formulas A and B, Lpy is the vertical pitch length of the fixed pixel, Lpx is the horizontal pitch length of the fixed pixel, and Dy is the vertical direction of the fixed pixel. Dx is the horizontal aperture of the fixed pixel, and Min (a, b) and Max (a, b) are a, a, respectively.
This function gives a small value and a large value of b. ] 6. The method according to claim 1, wherein the wobbling element includes a phase modulation optical element and a birefringent medium. 7. The wobbling element comprises a phase modulation optical element, a first birefringent medium, a half-wave plate, and a second birefringent medium, which are sequentially arranged. A / 2 wavelength plate rotates the plane of polarization of the light beam passing through the first birefringent medium by 90 degrees and guides the light beam to the second birefringent medium. The first birefringent medium and the second birefringent medium The method according to claim 1, wherein the pixel shift in the vertical direction and the pixel shift in the horizontal direction are independently performed in the birefringent medium. 8. The wobbling element is constituted by a phase modulation optical element and a birefringent medium which are sequentially arranged, and a polarization plane of the light beam emitted from the display element is inclined. The method according to claim 1, wherein the optical axis is shifted in an oblique direction. 9. The wobbling element is constituted by a phase modulation optical element and a birefringent medium which are sequentially arranged, and adjusts a phase of the light beam on an optical axis of a light beam emitted from the display element. 2. The display device according to claim 1, wherein the half-wave plate for performing the operation is disposed, and an optical axis is shifted in an oblique direction such that a polarization plane of the light beam emitted from the display element is in an oblique direction. 3. Drive method. 10. The wobbling element includes a phase modulation optical element, a first birefringent medium, and a second birefringent medium, which are sequentially arranged, and wherein the first birefringent medium and the second birefringent medium are arranged. In the birefringent medium of
The method according to claim 1, wherein the vertical pixel shift and the horizontal pixel shift are performed independently. 11. The method according to claim 1, wherein a 波長 wavelength plate is provided on the optical axis of the light beam and at a stage subsequent to the wobbling element. 12. The method according to claim 1, wherein the method is applied to a projector device.
3. The method for driving a display device according to item 1. 13. A display element having discrete fixed pixels driven by a signal obtained by sampling a video signal for each field, a wobbling element for causing wobbling in a light beam emitted from the display element, The sampling timing at the time of the first field scan and the second
A timing generation circuit for shifting sampling timing at the time of field scanning by a time corresponding to a pixel shift amount caused by wobbling by the wobbling element; and a display signal and the wobbling for each field by a timing signal of the timing generation circuit. A display device having a driving circuit for driving an element. 14. The display device according to claim 13, wherein the time corresponding to the pixel shift amount is a time amount corresponding to a horizontal pixel shift amount caused by the wobbling. 15. The display device according to claim 13, wherein the wobbling is caused by the time of the synchronization signal of each of the field scans, and the vertical pixel shift is performed simultaneously with the horizontal pixel shift. 16. The display device according to claim 13, wherein the pixel shift amount is an amount that minimizes the overlap between the fixed pixel and the pixel shifted by the wobbling. 17. The pixel shift amount in the vertical direction is ΔL
y, when the pixel shift amount in the horizontal direction is ΔLx,
17. The display device according to claim 16, wherein the pixel shift amounts satisfy the following Expressions A and B. Min (Lpy−Dy, Dy / 2) ≦ ΔLy ≦ Max (Dy, Lpy−Dy / 2) Expression A and Min (Lpx−Dx, Dx / 2) ≦ ΔLx ≦ Max (Dx, Lpx−Dx) / 2) ··· Formula B [wherein, in Formulas A and B, Lpy is the vertical pitch length of the fixed pixel, Lpx is the horizontal pitch length of the fixed pixel, and Dy is the vertical direction of the fixed pixel. Dx is the horizontal aperture of the fixed pixel, and Min (a, b) and Max (a, b) are a, a, respectively.
This function gives a small value and a large value of b. ] 18. The display device according to claim 13, wherein said wobbling element comprises a phase modulation optical element and a birefringent medium. 19. A wobbling element comprising: a phase modulation optical element arranged in sequence, a first birefringent medium,
A wave plate, and a second birefringent medium, and the polarization plane of the light beam that has passed through the first birefringent medium is rotated by 90 degrees by the 波長 wave plate. Guided to a second birefringent medium, the first birefringent medium and the second birefringent medium are configured such that vertical pixel shift and horizontal pixel shift are performed independently. The display device according to claim 13, wherein 20. The wobbling element, wherein the wobbling element is constituted by a phase modulation optical element and a birefringent medium which are sequentially arranged, and a polarization plane of the light beam emitted from the display element is inclined. 14. The display device according to claim 13, wherein the optical axis is shifted in an oblique direction. 21. The wobbling element is constituted by a phase modulation optical element and a birefringent medium which are sequentially arranged, and a phase of the light beam is set on an optical axis of a light beam emitted from the display element. The half-wave plate for performing the adjustment is arranged, and the optical axis is shifted obliquely so that the polarization plane of the light beam emitted from the display element is oblique. The display device according to claim 13, wherein 22. The wobbling element is constituted by a phase modulation optical element, a first birefringent medium, and a second birefringent medium which are sequentially arranged, and wherein the first birefringent medium and the In the second birefringent medium,
14. The display device according to claim 13, wherein a vertical pixel shift and a horizontal pixel shift are performed independently. 23. The display device according to claim 13, wherein a 波長 wavelength plate is provided on the optical axis of the light beam and at a stage subsequent to the wobbling element. 24. The display device according to claim 13, wherein the display device is configured as a projector device.