JP3331575B2 - Optical device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to liquid crystal, plasma, EL
The present invention relates to an optical device suitable for a display having discrete pixels such as (electroluminescence) and a solid-state imaging device represented by a CCD (charge coupled device) having discrete imaging pixels.

[0002]

2. Description of the Related Art For a display element having a discrete pixel arrangement such as a mosaic or a dot such as a liquid crystal, a plasma, an EL, or the like, when performing line sequential scanning pixel display by the NTSC method or the like, an analog signal is originally used. A luminance signal that should be a signal is roughly sampled, and horizontal position information is lost. Further, when the vertical pixel resolution cannot be implemented by the number of scanning lines, the position resolution of a luminance signal or the like (ie,
Display resolution).

[0003] For example, a TFT (T
In the hin-Film-Transistor) -TN (Twisted Nematic) liquid crystal viewfinder, in the NTSC system, one frame (that is, one picture displayed by the viewfinder) is composed of even-numbered scanning lines and odd-numbered scanning lines. And the frame frequency is 30 Hz (that is, the field frequency is 60 Hz). Since the current TFT viewfinder cannot mount 525 scanning lines in the NTSC system, a method such as writing an odd field and an even field in the same pixel is used. For this reason, the vertical resolution is currently lower than the principle of the NTSC system.

[0004] In addition, due to the large pixel size and the presence of seams of non-display pixels such as a black matrix, a mosaic screen having a discrete pixel array is conspicuous, and the texture of the screen is reduced.

[0005] The above-mentioned phenomenon also occurs in CCD image pickup. That is, since the captured image forming the CCD is discrete, the image information of the subject is sampled at the constituent pixel pitch, so that the horizontal and vertical spatial resolution is reduced.

Therefore, there has been proposed a method of improving the vertical resolution by introducing a picture element shifting element by adopting a wobbling technique and spatially shifting an image of an odd field and an even field. This applies to the horizontal direction, and the horizontal resolution can be improved.

[0007] However, the wobbling element proposed so far has a low response speed and cannot be driven at a video rate, so that it is not practical and the configuration conditions of the device are insufficient.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to enable high-speed wobbling (picture element shifting) for a display composed of discrete pixels, a solid-state image pickup device composed of discrete light-receiving pixels, etc. It is an object of the present invention to provide an optical device capable of efficiently achieving image formation and improving a mosaic-like point-drawing screen or the like into a continuous screen without any seams.

Another object of the present invention, in addition to the above objects, is to provide a device having a high performance at a low cost, which enables higher contrast, higher resolution, and suppression of color unevenness.

[0010]

That is, according to the present invention, a plurality of optically transparent substrates provided with an optically transparent electrode and an alignment film in this order are arranged on the side of the electrode and the alignment film. The ferroelectric liquid crystal (FL) is disposed opposite to each other with a predetermined gap therebetween.
C), an antiferroelectric liquid crystal (AFLC), and a smectic liquid crystal (SmA) exhibiting an electroclinic effect.
A phase modulation optical element in which a kind of liquid crystal (which may be a mixed liquid crystal) is injected into the gap; and a liquid crystal element arranged at a position for receiving polarized light transmitted through the phase modulation optical element, according to the polarization direction of the light. An optically transparent birefringent medium for selectively shifting the optical axis of the light by rotating the plane of polarization by about 90 degrees over a wide wavelength range; And a phase adjustment medium for shifting the optical axis. The phase modulation optical element, the birefringent medium, and the phase adjustment medium are arranged between the observation position and the display element to be improved in resolution. An optical device which is arranged in an optical path between a subject or an image sensor and forms a wobbling element, and wherein the display element or the image sensor is wobbled one-dimensionally or two-dimensionally. is there.

According to the optical apparatus of the present invention, the phase modulation optical element changes the phase of light to shift the plane of polarization, and the birefringent medium selectively refracts incident light. The wobbling can be effectively performed on the pixels, the resolution can be improved, and the image quality can be improved. In particular, the spatial resolution at the video rate can be improved, and the mosaic-like point drawing screen can be improved to a continuous screen without any seams.

The liquid crystal such as ferroelectric liquid crystal used in the above-mentioned phase modulation optical element easily changes the direction of the liquid crystal director in response to the action of an electric field, and has a very fast response speed (for example, rising and falling). Both fall time μ
Since it is in the order of sec and is much faster than the falling time of the twisted nematic liquid crystal, the driving at the video rate is sufficiently possible.

In the present invention, a phase modulation optical element, a birefringent medium, and a phase adjusting medium are provided between a display element to be improved in resolution and an observation position or in an optical path between a subject and an image pickup element. The display element or the imaging element is wobbled one-dimensionally or two-dimensionally.

Further, the birefringent medium is made of a transparent substrate made of quartz or the like which shifts the optical axis depending on the polarization direction of the incident light, and is arranged so as to have a uniaxial extraordinary optical axis component equivalently in the wobbling direction. Alternatively, the light-transmitting substrate-facing surface may not be parallel, and the apparent extraordinary optical axis may be parallel or perpendicular to a plane perpendicular to both planes.

In the present invention, the polarization plane is provided with a polarization plane of about 90 in a wide wavelength range at the rear and / or front of the phase modulation optical element.
It is important that a phase adjusting medium for rotating the optical axis by rotating by an angle is further provided.

With this configuration, it is possible to widen the wavelength range of light for rotating the plane of polarization by about 90 degrees in high resolution, and to achieve high contrast, high resolution, and suppression of color unevenness. . Also, since the wavelength range in which the wobbling effect can be obtained can be extended to the entire visible light region,
In particular, it is possible to increase the resolution of a display element or an imaging element composed of three plates of red (R), green (G), and blue (B) with a single wobbling element, thereby reducing costs. Can be.

In addition, the phase compensation by the phase adjustment reduces the deviation of the phase difference of the chiral smectic element, that is, the condition of the deviation of the gap accuracy, thereby improving the yield. Since the effect of the low-pass filter can be sufficiently exerted in the image sensor, an image with high resolution and reduced moiré fringes, false color signals, and the like can be captured.

In this case, the phase adjustment medium may be any one of an element made of a liquid crystal material containing a π-electron system, an active liquid crystal element having a liquid crystal interposed at least between transparent electrodes, and a polymer film containing a π-electron system. It is desirable to reduce the crosstalk as an integral amount in the used wavelength range between fields during wobbling as compared with a wobbling element in which phase adjustment is not performed.

The phase adjusting medium includes an optically transparent and uniformly oriented smectic liquid crystal (including chiral liquid crystal) element, a nematic liquid crystal element, a main chain type polymer liquid crystal, and a side chain type polymer liquid crystal. Aromatic polyester film, polycarbonate film, polystyrene or styrene resin film, methacrylic resin film, vinyl resin film, cellulose film, polyamide resin film, polyphenylene film,
Polyphenylene sulfide-based film, polysulfone-based film, amorphous polyalate film, polyethersulfone-based film, polyetherimide-based film, polyetherketone-based film, polyamide-imide-based film, and polyimide-based film May be constituted by any of the above.

Further, a phase adjusting film constituting a wobbling element for a display element is not directly adhered to a phase modulation optical element composed of a chiral smectic liquid crystal, and a phase adjusting film constituting a wobbling element for an image pickup element is provided. It is preferred that the film and the polarizing plate are not directly attached to the phase modulation optical element made of chiral smectic liquid crystal.

Then, the polarization plane is rotated by about 90 degrees in a wide wavelength range, and the phase difference of the phase modulation optical element made of a chiral smectic liquid crystal and the phase difference of the phase adjusting medium are further reduced so as to minimize the wobbling crosstalk. Can adjust the directions of the axis of incident polarized light, the slow axis of the phase modulation optical element, the slow axis of the phase adjustment medium, and the direction of the extraordinary optical axis of the birefringent medium for shifting the optical axis.

The alignment direction of the phase modulation optical element made of a chiral smectic liquid crystal may be parallel or perpendicular to the pixel shifting direction, and the alignment processing may be performed by rubbing or vacuum deposition.

Further, the phase difference at 632.8 nm of the phase modulation optical element composed of a chiral smectic liquid crystal is 160 nm to 380 nm.
That the phase adjustment medium shows a retardation of 160 nm to 380 nm, and has the same phase difference as the phase difference at 632.8 nm of the phase modulation optical element composed of chiral smectic liquid crystal, and two of the liquid crystal director of the phase modulation optical element. It is desirable that the slow axis of the phase adjustment medium be substantially orthogonal to the slow axis in either of the switching states.

Further, a liquid crystal display element such as a twisted nematic liquid crystal, a ferroelectric liquid crystal or an antiferroelectric liquid crystal in which a display element or an image pickup element to be improved in resolution is composed of discrete pixels, and a self-luminous light such as a light emitting diode. Type display element or CCD
And so on.

When the light from the display element or the object to be improved in resolution is not polarized, it is preferable that an element for giving polarization is arranged in the optical path between the wobbling element and the display element or the object. .

The liquid crystal used in the present invention may be a bookshelf, a pseudo bookshelf or a chiral smectic liquid crystal having a liquid crystal layer structure of a chevron structure.

In this case, the pretilt angle of the chiral smectic liquid crystal is desirably 0 to 45 degrees. The apparent cone angle θ of the liquid crystal used is desirably 26 to 64 degrees.

The bisector between the directors of the liquid crystal used in the phase modulation optical element of the present invention in the two switch states is the polarization plane (P1) of the light from the display element or a line (P2) orthogonal to it. ) Is preferably 22.5 ± 10 degrees when phase adjustment (or compensation) is not performed. Alternatively, in each of the switch states after the phase compensation in the two switch states of the liquid crystal in the phase modulation optical element that has been subjected to the phase adjustment (or compensation), between the slow axis of birefringence having a large absolute value and P1 or P2. The bisector of
It is desirable that the angle δ1 between the polarization plane (P1) of the light from the display element and the line (P2) orthogonal thereto is in the range of δ1 = 22.5 ± 10 degrees.

When the liquid crystal display or the image pickup device as a display device to be improved in resolution is a single plate having red, green and blue trio pixels as one picture element, 632.8 nm
The phase difference measured using the above light source is preferably in the range of 130 nm to 370 nm.

When the liquid crystal display or the image pickup device as a display device to be improved in resolution has three plates, the upper limit of the wavelength range of the transmittance characteristic of each filter to be combined is λ.
_If the lower limit is λ _Min and the lower limit is λ _Min , the allowable phase difference is in the range of λ _Max / 2 to λ _Min / 2,
Green, in the case of using the light emission of the blue phosphor, when each of the effective phase difference range in which the center wavelength and λ _C (λ _C -10
0) / 2 to (λ _C +100) / 2 (however, the unit of each phase difference is nm).

When the image pickup element is combined, when the image pickup wavelength includes infrared light (wavelength 700 to 1200 nm), 632.8 nm
It is preferable that the phase difference measured using the above light source is in the range of 350 nm to 600 nm.

The phase modulation optical element can be driven by using a bipolar applied voltage such as rectangular wave drive or pulse drive.

In this case, at the time of wobbling, the response time of the rise and fall of the drive voltage is not more than 1/3 of the field time, and the ratio between the rise time and the fall time does not exceed twice as large. Is desirable.

Picture element diameter for the length component in the wobbling direction (pixel aperture for monochrome screen or three boards, one pixel trio for red, green, and blue for single board)
Where L _{A is} the pixel pitch and L _P is the pixel pitch, the pixel shift amount L
_{Is, Min (L P -L A,} L A / 2) ≦ L ≦ Max (L A,
L _P −L _A / 2) (however, Min (x, y) and Max (x, y) are preferably functions giving smaller and larger values of x and y, respectively). .

A display element having the number N of horizontal scanning lines, and N to 1 divisions (preferably N to 3 divisions, further N / 2 divisions or (N + 1) / 2) in the vertical direction of the screen of the display elements.
Below division, three or more divisions are preferred. It is preferable to combine a phase modulation optical element having the driving electrodes described above.

In this case, the distance between the divided electrodes is preferably longer than the liquid crystal cell gap (further shorter than the non-display portion such as the black matrix portion).

At the time of wobbling, the driving of the display element and the driving of the phase modulation optical element are synchronized based on the detected video vertical synchronizing signal, the time of one field is divided by the required number of electrodes, and each channel of the phase modulation optical element is divided. With this, a time delay in the field can be sequentially given and driving can be performed.

Further, based on the synchronization signal, the drive of the image pickup device and the drive of the phase modulation optical device are synchronized with each other, an image is taken in each field, and data is transferred to form one frame.

In the optical device of the present invention, the birefringent medium for shifting the optical axis and the phase modulation optical element are bonded with an optical adhesive, or the transparent electrode and the orientation are attached to a quartz plate as the birefringent medium. A film can be provided and integrated with the liquid crystal element.

Further, it can be configured as a direct-view, reflection-type or projection-type display device, or can be used in the wavelength range of visible light.

Further, the wobbling element can be combined with a solid-state image pickup element to constitute a visible light or infrared light image pickup apparatus.

Further, the wobbling element, the optical low-pass filter, and the solid-state image sensor can be combined,
In this case, a quarter-wave plate is preferably disposed in the optical path between the wobbling element and the optical low-pass filter.

[0043]

Embodiments of the present invention will be described below.

FIGS. 1 and 2 schematically show an example of an optical device incorporating a wobbling element according to the present invention.

In this example, the present invention is applied to a liquid crystal optical display device 1, in which a liquid crystal display element (LCD) 2 sequentially arranged in the same optical path along the traveling direction of light, and a phase modulation optical Ferroelectric liquid crystal device (FLC) 3 as device
And a birefringent medium 4 made of a transparent substrate such as a quartz plate. Here, for ease of understanding, each constituent element is shown for a section corresponding to one constituent display pixel 5 of the liquid crystal display element LCD (the same applies hereinafter).

The pixel 5 of the LCD 2 has a discrete pixel arrangement such as 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
Although not shown, the panel 2 has a polarizing plate on the panel itself and the output light 6 has linearly polarized light, as is well known.

Then, for the linearly polarized light 6, the above F
A picture element is shifted in the parallel or 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). X of the extraordinary optical axis 10 of the transparent substrate 4 having
The projection component on the −Y plane (incident side) is arranged parallel (Y direction) or perpendicular (X direction) to the polarization plane 9.

The liquid crystal used for 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 or the like. However, as described later,
Instead of LC, 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 in the display device 1 will be schematically described.

First, as shown in FIG.
Is in the state 1, the polarization plane 9 of the light 6 emitted from the display element 2 side is parallel to the extraordinary optical axis 8 of the ferroelectric liquid crystal element 3, so that the transmitted light 11 maintains the polarization plane. The light is applied to the crystal plate 4 having birefringence. In the quartz plate 4, since the extraordinary optical axis 10 of the quartz is included in the incident polarization plane, the light polarized in the Y-axis direction is refracted in the direction in which the extraordinary optical axis 10 of the quartz plate 4 is inclined, and the air layer is again formed. When the light exits as 12, the light becomes parallel to the optical axis, and the deviation of the incident light from the optical axis occurs in the Y direction.

On the other hand, as shown in FIG.
Is the state 2, the polarization plane 9 and the extraordinary optical axis 8
Has an angle of about 45 degrees, the transmitted light 11 rotates in the direction of the extraordinary optical axis, and becomes linearly polarized light (Y-axis direction) → elliptically polarized light → circularly polarized light → elliptically polarized light → linearly polarized light (X-axis direction). The inside of the ferroelectric liquid crystal element 3 changes, and the plane of polarization is rotated by 90 degrees from the initial state, and is irradiated on the quartz plate 4. 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 maintained as it is without being refracted, and exits to the air layer again as the outgoing light 12.

As described above, the optical axis is shifted depending on 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 the shift of the optical axis is used as an operation principle of the picture element shifting. it can.

Here, the cone angle of the liquid crystal that determines the switch state in the FLC 3 will be described. In a ferroelectric liquid crystal (similarly in an antiferroelectric liquid crystal), the switching behavior of a liquid crystal director by applying an electric field is such that the liquid crystal molecules follow a southern-goldstone mode described in P150 of “Liquid Crystal Dictionary” (published by Baifukan). Move on a virtual cone. Further, smectic A having an electroclinic effect
The liquid crystal (P145 of the liquid crystal dictionary) has a cone angle unique to each liquid crystal composition similar to the cone angle even when the soft mode described in P119 of the liquid crystal dictionary is used.

That is, consider a cone model of the liquid crystal 15 sandwiched between transparent electrodes 13-14 made of ITO (indium tin oxide doped with indium) as shown in FIG. The opening angle of the cone is called a cone angle θr, and the projection of this cone angle onto a glass substrate provided with a transparent electrode is called an apparent cone angle θ. Optically, the apparent cone angle θ may be considered. This cone angle shows temperature dependence as shown below, so even if a cone angle of 45 degrees is obtained at 25 ° C, for example, in order to obtain an effective wobbling effect, the cone angle will be lower on the low temperature side due to its environmental temperature. There is a phenomenon that the cone angle is large and the cone angle is small on the high temperature side.

For example, as shown in the following Table 1 and FIG. 4, an antiparallel cell with an obliquely vapor-deposited alignment film of SiO using FLC liquid crystal CS-1014 manufactured by Chisso Petrochemical Co., Ltd.
The apparent cone angle is about 45 degrees near 0 ° C, but it is as large as about 51.6 degrees at 0 ° C and drops to 7 degrees at 55 ° C. As shown in Table 2 below and FIG. 5, in a similar cell using FLC liquid crystal ZLI-3774 manufactured by Merck, the apparent cone angle is about 45 degrees at 25 ° C., but −45 ° C. on the low temperature side. It becomes as large as 54.8 degrees at 10 ° C.

[0057]

[0058]

As described above, if the apparent cone angle θ, that is, the angle formed by the extraordinary optical axis 8 of the liquid crystal before and after switching deviates from 45 degrees, the ideal rotation of the polarization plane of 90 degrees as described above can be achieved. However, various problems occur.

Further, to examine the effect of the cone angle, 25
CS-2003 (cone angle 60 degrees), CS-2002 (cone angle 64 degrees) and CS-2004 (cone angle 88 degrees) manufactured by Chisso Petrochemical Co., Ltd. can be used as liquid crystals having a large cone angle at ° C. These are all Iso-N ^* -SmC
^* A composition showing -Cryst. And cone angle 65 ~
An 80 degree composition is CS-2002 (cone angle 64 degrees) and C
Prepared by blending S-2004 (cone angle 88 °).

The measurement of the cone angle is to measure the angle formed by the liquid crystal director in two switch states. Specifically, the liquid crystal cell is observed under a polarizing microscope in which the polarizers are orthogonal, and the extinction position is measured. It was determined from the rotation angle of the stage at (the position where it turns dark).

The present inventor has found, as a result of diligent efforts, that the following combinations of optical axes are effective.

The apparent cone angle is
Deviates from 45 degrees (for example, 45 + γ degrees: where γ is 45>γ>
-45) In the wobbling operation, if the optical axis of the liquid crystal director in one of the switch states is ideally aligned parallel or orthogonal to the polarization plane on the display element side, the polarization plane of the transmitted light in this switch state becomes It does not change. In this case, since the polarization plane is not rotated, 100% of the light is refracted in the direction of the extraordinary optical axis 10 of the quartz plate 4 as shown in FIG. At this time, there is almost no component on the Z axis.

In the other switch state, 45+
When γ is positive, the plane of polarization of transmitted light is 90
When the γ is negative, the plane of polarization does not rotate to 90 degrees. When the plane of polarization is completely rotated by 90 degrees, the component on the Z axis is almost 100% as shown in FIG.
As shown in the above, when the rotation of the polarization plane deviates from 90 degrees by an angle of γ, the component in the Y-axis direction also increases as the polarization component, so that a component shifted in the Y-direction is included in addition to on the Z-axis. Become like Therefore, in this case, the effect of the pixel shift which should be originally made higher in resolution is reduced.

In particular, it has been found that the effect of reducing the effect of increasing the resolution is due to a leak component when shifting pixels.

Here, the cone angle of the liquid crystal shown in FIG. 6 will be further described. If the cone angle of the liquid crystal is not 45 degrees,
As shown in FIG. 7, light leakage (that is, crosstalk) occurs between the odd field and the even field. As a result, for example, if the odd field is white and the even field is black, if wobbling is performed completely, fringes will be observed with sufficient contrast, but if there is a leak component, white will be dark and black will be bright, The contrast decreases.
For example, if the contrast of the original display element is 100: 1, if there is 10% crosstalk between fields, 100%
White level is 90.1%, 0% white level (black level) is
10.9%, which is 90.1: 10.9 = 8.27: 1, and the contrast is considerably reduced.

That is, since a contrast of 8: 1 or more is necessary to endure practical use as a display, it is important to suppress crosstalk between fields to about 10% or less (only when the contrast is guaranteed, the resolution is increased). Effect is confirmed).

FIG. 8 shows an optical system for evaluating the amount of crosstalk. The optical system includes a polarizing microscope (OPTIPHOTO-POL manufactured by Nikon) 70,
It comprises a visible spectrophotometer (Otsuka Electronics Co., Ltd. 100) 71, a personal computer and a monitor 72.

The light emitted from the halogen light source 73 is a polarizer 74 / F
The light passes through the LC element 7 / analyzer 75, passes through the quartz fiber 76, and is separated by the visible spectroscope 71, whereby the spectrum can be obtained. Here, the polarizer 74 and the analyzer 75 are installed in parallel, and when the polarization plane is not rotated by the FLC 7, the light transmitted through the polarizer 74 passes through the 100% analyzer 75 and the spectrometer 71. Will be introduced. However, if the deviation of the FLC molecular director from the Y axis is ζ, and ζ is not zero,
Light from the polarizer 74 undergoes rotation of the plane of polarization. With ζ = 45 degrees, adjusting the gap further allows the plane of polarization to be rotated exactly 90 degrees. As a result, it does not pass through the analyzer 75,
The transmittance becomes 0%.

Here, the rotation characteristics of the polarization plane when this liquid crystal director was rotated corresponding to the change in the cone angle were evaluated. That is, if the transmittance is 0%, sufficient wobbling can be performed, and if the transmittance is, for example, 10%, 10% of the incident light leaks to the field component on the opposite side. Thus, actual experimental results are shown below.

FIGS. 9 and 10 show the spectrum change when と き is changed. Furthermore, for the wavelength of the minimum transmittance, the transmittance change when ζ is changed is set to the maximum transmittance of 100%.
FIG. 11A or FIG. 11B.

Here, 0 ° or less has a mirror image relationship at 0 °, and 45 ° or more has a mirror image relationship at 45 °. In order to ensure a contrast of 8 or more (that is, the transmittance is 10% or less,
Or 90% or more), and ζ needs to be about ± 10 degrees or less, and 36 degrees to 54 degrees.

Theoretically, the transmittance when the polarizer and the analyzer are parallel is expressed by I / I _O = sin ² (2ζ) · cos ² (πΔn · d / λ). Here, λ is the wavelength, Δn is the birefringence, and d is the cell gap. When the transmitted light intensity is calculated and plotted assuming the phase term πΔn · d / λ = π, it almost corresponds to the actually measured value, but it can be seen that the actually measured value has less restrictive conditions (FIG. 11B). reference).

Further, in order to obtain a contrast of 40 or more by the above method, the transmittance must be 1.5% or less.
For that purpose, ζ needs to be about ± 5 degrees or less, and 41 degrees to 49 degrees. That is, when this is converted into an apparent cone angle, the range in which high resolution can be obtained by wobbling is 26
It has been found that ~ 64 degrees, more preferably 36-54 degrees, is required. It is clear that the same applies to the other quadrants shown in FIG.

Therefore, as shown in FIG. 13, in order to improve the reduction in resolution (asymmetry) at the time of pixel shift, the bisector 16 of the angle formed by the above two switch states is set to a distance from the display element. Ideally, the angle δ between the plane of polarization of light (Y direction) or a line perpendicular to the plane of polarization (X direction) is
It turns out that it is only necessary to make an angle of 22.5 degrees.

By arranging the direction of the liquid crystal director 8 as described above, crosstalk occurs in both switch states as shown in FIGS. 14 and 15.
The crosstalk in each switch state is small, and the sum is averaged and smaller than the case where crosstalk occurs only on one side, so that the effect of high resolution is not reduced.

When the range of the δ axis is considered in the same way as described above, when the apparent cone angle θ is 26 degrees or 64 degrees, δ
= 22.5 degrees only, but when the apparent cone angle θ is 45 degrees, the range of δ is better for δ = 22.5 ± 10 degrees, and more preferably δ = 22.5 ± 5 degrees is required. .

Here, the range of the cone angle θ, and
The angle δ formed by the bisector of the switch state with the polarization plane of the light from the display element or a line perpendicular to the polarization plane was clarified from the following wobbling experiment results.

That is, when examining the fixing of the shaft on one side, θ = 26 to
In the range of 64 degrees, the resolution could be increased from 240 TV lines of the original liquid crystal display element to be increased to 370 TV lines or more by the wobbling effect. Further, in the range of [theta] = 36 to 54 [deg.], High resolution with little coloring was achieved. As a result of examining the position of the δ axis in the range of θ = 36 to 54 degrees, it was found that when δ = 22.5 ± 10 degrees, there was almost no coloring, and the resolution could be increased to 370 lines or more. Further, θ = 36 to 54 degrees, δ = 2
In the range of 2.5 ± 5 degrees, crosstalk between fields was reduced and the contrast ratio between fields was increased. Therefore, it was visually confirmed that the resolution was further increased to 390 lines or more.

The resolution evaluation is performed by inputting a signal from an NTSC resolution evaluation pattern (video signal pattern generator: MTSG-1000 manufactured by Sony Corporation) as a video signal and observing the resolution of black and white lines by observation. (The same applies hereinafter).

Next, with respect to the phase difference, since the liquid crystal itself has a wavelength dependency in the amount of birefringence, it is difficult to match over the entire wavelength range. The case where the liquid crystal display to be improved in resolution is a single plate of RGB trio pixels (forming one pixel) (however, in the case of monochrome, one pixel = 1 pixel) was examined. As shown in FIG. 16, the RGB filters used here have main transmission wavelengths of 650 nm (R), 550 nm (G), and 450 nm, respectively.
exists in m (B). Here, considering the visibility with respect to the resolution of the human eye, the sensitivity ratio is R (red): G
Since (green): B (blue) = 3: 6: 1, a phase difference of a half wavelength with respect to the weighted average wavelength obtained by weighting the sensitivity of these main wavelengths may be provided.

That is, the optimum phase difference = 450 nm × 0.1 + 55
0 nm x 0.6 + 650 nm x 0.3 = 570 nm, so it is sufficient to adjust the half wavelength to 285 nm. The phase shift of half a wavelength is important for effectively rotating the plane of polarization as described later.

The results of actually examining the pixel shift using ferroelectric liquid crystal elements having various phase differences are shown in Table 3 below.
Shown in According to this, the effect of increasing the resolution was recognized in the range of a phase difference of 130 nm to 370 nm measured using a 632.8 nm light source (He-Ne laser light). Among the cells with higher resolution, with a phase difference of less than 137 nm and a phase difference of more than 350 nm, the coloration of the screen was large and it became difficult to use. Therefore, when increasing the resolution of a single panel in which RGB are scattered in a mosaic pattern, a light source of 632.8 nm (H
phase difference measured using e-Ne laser light) is 140 nm
More preferably, it is in the range of -350 nm.

[0084]

[0085]

Further, when the liquid crystal display to be improved in resolution is a three-panel projection display, a phase difference may be set for each of the R, G, and B color filter characteristics. In this case, assuming that the upper limit of the wavelength range of the transmittance characteristic of each filter is λ _Max and the lower limit is λ _Min , the allowable phase difference is preferably in the range of λ _Max / 2 to λ _Min / 2.

When light emission of R, G, and B phosphors is used as a light source, R, G, and B have emission line spectra.
Under this condition, it becomes very narrow. Usually, R, G,
The wavelength range of each filter is B filters has crossover, has a width of ± 100 nm with respect to the center wavelength lambda _C. Therefore, here, a range of ± 100 nm from the center wavelength of each light source is effective as the wavelength range. That is, the effective phase difference range is preferably in the range of (λ _C −100) / 2 to (λ _C +100) / 2 (each unit is nm), where λ _C is the center wavelength.

Next, the switch states of specific examples of combinations of the elements constituting the liquid crystal optical device according to the present invention are shown.
See Figure 17. The liquid crystal display element 2 to be combined here may be of any type, such as an active matrix TN liquid crystal, STN liquid crystal display element, ferroelectric liquid crystal display element, antiferroelectric liquid crystal display element, SH display element, and the like. Here, as an example, a combination example with a TN liquid crystal is shown.

In the case of a normally white TN liquid crystal display device shown in FIG. 18, light from a light source is transmitted when no electric field is applied to the TN liquid crystal. Here, a combination of a backlight 17-a polarizing plate 18-a TN liquid crystal 2-a polarizing plate 19, or a reflecting plate-a polarizing plate 18-a TN liquid crystal 2-a polarizing plate 19
Shows a TN liquid crystal display element similar to the conventional one.
Needless to say, the TN liquid crystal element 2 and the ferroelectric liquid crystal element 3 each have transparent electrodes disposed on both sides 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 a gradation display is realized. However, any transmitted light has the same linear polarization 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 the case of the normally black TN liquid crystal display element shown in FIG. 19, the mode is such that light is transmitted when an electric field is applied to the TN liquid crystal, and the twist of the TN liquid crystal 2 gradually decreases as the electric field intensity decreases. It returns, gradually darkens,
Although gradation display is realized, any transmitted light is converted into the same linearly polarized light by the polarizing plate 19 in front of the ferroelectric liquid crystal element 3, so that the picture element can be shifted in accordance with the above-described operation principle.

As described above, it is clear that the present invention can be applied to any type of liquid crystal display device if the light emitted from the display device is substantially linearly polarized light.

Although the above-described example is for a display element having polarized light, the present invention can of course be applied to a non-polarized display element.

As shown in FIG. 20, when the degree of polarization of the light from the display pixel 5 is small, a polarizing plate 19 is inserted into the optical path connecting the display element 2 and the picture element shifting element 7 to make the light polarized. good. The optical arrangement conditions are the same as in the case of the liquid crystal display element described above.

As the non-polarized display 2 that can be used here, there are self-luminous display elements such as a plasma display and an LED display.

As described above, based on the present invention, a phase modulation element such as a chiral smectic liquid crystal which can be driven at a video rate (a ferroelectric liquid crystal, an anti-ferroelectric liquid crystal, or a smectic A liquid crystal having an electroclinic effect). 3.) A wobbling element 7 using 3 is arranged in an optical path connecting a display such as a liquid crystal, a plasma, an LED or the like composed of discrete pixels to a retina of an observer, and wobbling (pixel shifting).
Here, the phase modulation element 3 includes the following [1], and the birefringent medium includes the following [2].

[1] At least two states exist in the switch state of a ferroelectric liquid crystal, an antiferroelectric liquid crystal, or a smectic A liquid crystal having an electroclinic effect, which can be driven at a video rate. A chiral smectic liquid crystal element with an extraordinary optical axis at an angle of 26 to 64 degrees, which is optically arranged so that the plane of polarization can be rotated. [2] A transparent substrate that shifts the optical axis depending on the polarization direction of the incident light. Specifically, (a) the transparent substrate is disposed so as to have a uniaxial extraordinary optical axis component equivalently in the wobbling direction. (B) An element in which a substrate facing surface through which light passes is not parallel, and an apparent extraordinary optical axis is parallel or perpendicular to a plane perpendicular to both planes.

Next, a specific manufacturing method and operation characteristics of the constituent elements (cells) of the element 3 will be described.

[1] Ferroelectric Liquid Crystal Switching Element The structure of the cell is as shown in FIG. That is, a transparent electrode (eg, 100Ω / □ ITO) is provided on the transparent glass substrates 20 and 21.
13 and 14 are further provided, and Si
O oblique deposition films 22 and 23 were formed. In the method of forming the SiO oblique deposition film, a substrate was disposed vertically from a SiO deposition source in a vacuum deposition apparatus, and an angle between a vertical line and a substrate normal was set to 85 degrees. After vacuum deposition of SiO at 170 ° C substrate temperature,
The firing was performed at 300 ° C. for one hour.

The substrate with the alignment film thus manufactured is assembled so that the alignment processing direction is anti-parallel on the opposing surface, and glass beads (thread: diameter: diameter) corresponding to the target gap length are used as spacers. 0.8 to 3.0 μm (manufactured by Catalyst Chemicals)) 24 was used. Depending on the size of the transparent substrate, the spacer is a sealing material (UV
Curable adhesive (Photorec: Sekisui Chemical Co., Ltd.)
The gap between the substrates was controlled by dispersing, for example, about 0.3 wt% in 25). When the substrate area is large, the above-mentioned true ball is placed on the substrate at an average density of 100 pieces / mm ^2.
After spraying, a gap was formed, a liquid crystal injection hole was secured around the cell, and the periphery of the cell was adhered with the sealing material.

Thereafter, a ferroelectric liquid crystal (for example, CS-1014 manufactured by Chisso Corporation) was injected under reduced pressure while exhibiting fluidity at an isotropic phase temperature or a chiral nematic phase temperature. After the injection of the liquid crystal, the liquid crystal was gradually cooled to remove the liquid crystal on the glass substrate around the injection hole, and then sealed with an epoxy-based adhesive to produce a ferroelectric liquid crystal element. The ferroelectric liquid crystal used may be manufactured by Chisso Co., Ltd., manufactured by Merck Co., Ltd., manufactured by BDH, or may be, for example, a ferroelectric liquid crystal compound described below or a composition comprising an achiral liquid crystal containing these compounds. There is no need to limit the phase series, and it is necessary to obtain a chiral smectic liquid crystal phase in the operating temperature range.

The liquid crystal layer structure of the chiral smectic liquid crystal element used here has an antiparallel bookshelf structure and a parallel chevron structure or pseudo bookshelf structure according to the combination of the alignment treatment directions. Analysis clarified it.

[0103]

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[0104]

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[0105]

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[0106]

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[0107]

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Further, in addition to the chiral smectic liquid crystal, if the switching speed is high, for example, the following antiferroelectric liquid crystal (AFLC) or a smectic A phase exhibiting an electroclinic effect can be applied.

<Antiferroelectric Liquid Crystal> The antiferroelectric liquid crystal is C
It was discovered in 1988 by handani et al. and has the following three features. (1) Utilizing switching between an antiferroelectric state and three stable states of two ferroelectric states. (2) A clear threshold characteristic is exhibited, and the contrast at the time of multiplex driving can be increased. (3) Use positive and negative hysteresis alternately,
Since the occurrence of internal polarization is suppressed, the burn-in phenomenon does not easily occur.

The characteristics of this antiferroelectric liquid crystal material are as follows.
Unlike ferroelectric liquid crystals, chiral liquid crystals are the majority of the composition (large spontaneous polarization, almost 10 times that of ferroelectric liquid crystals), and the substituent for asymmetric carbon is CH
₃ group, CF ₃ group, compounds having C ₂ H ₅ group is readily indicates the antiferroelectric, the core structure is expanded. For example, there is CS-4000 manufactured by Chisso Corporation.

<Smectic liquid crystal exhibiting electroclinical effect> The electroclinical effect is a phenomenon in which, in a smectic A phase composed of chiral molecules, an electric field induces a tilt angle of an orientation vector when a temperature is constant. . In the smectic A phase, the orientation vector is oriented in the normal direction of the smectic layer and freely rotates around its long axis. However, the application of an electric field along the layer inhibits the free rotation and causes the polarization P in the electric field direction to change. Induced.

Assuming that a linear combination of the polarization P and the inclination angle θ is P = kθ, P = (ε⊥ ^* −ε⊥0) ε _O Ε Therefore, θ = (ε⊥ ^* −ε⊥0) ε _O An inclination angle proportional to the applied electric field E occurs, such as Ε / k. Here, .epsilon..perp ^* and ε⊥0 dielectric constant of the racemate of the optically active substance, the epsilon _O is the dielectric constant of a vacuum. From this, the greater the difference between the respective dielectric constants of the racemic chiral liquid crystals, the greater the electroclinical effect.

Adjustment of phase difference by birefringence: Table 4 below shows the birefringence and phase transition temperature of the ferroelectric liquid crystal used in the FLC device.

[0114]

In the wobbling operation described above, the phase may be shifted by 180 degrees in order to rotate the polarization plane of the liquid crystal by 90 degrees. Birefringence (n _e -n _o), the following relationship exists between the cell gap d and the phase difference [delta]. _{δ = 2πd (n e -n o} ) / λ

Here, it is sufficient to set δ = π. For this purpose, comprising a cell gap d that may be set _{d = λ / 2 (n e} -n o). In practice, however, the angle alpha (pretilt angle) to the substrate of the liquid crystal molecules in order not 0 degree, n _e is small, must take a longer gap length d.

[0117] Here, ordinary n _o is independent of the angle of incidence is equal to the refractive index of the liquid crystal molecules minor axis direction n⊥. In other words, n _o = n
⊥.

[0118] More specifically, a function of n _e is the pre-tilt angle α,

(Equation 1)

D depends on the pretilt angle α as follows. d = λ / 2 [n _e (α) -n _o]

That is, α is determined according to the type of the alignment film, and the optimum gap d can be calculated based on the above relational expression. Therefore,
The alignment film can be used regardless of the type of an inorganic alignment film such as SiO or an organic alignment film such as polyimide, polyamide or polyvinyl alcohol (PVA).

Further, when the pretilt angle α is 90 degrees, the gap length d becomes infinite according to the above equation.
A pretilt angle of ~ 89 degrees is required. However, since it is difficult to control the pretilt angle beyond 45 degrees, a pretilt angle of 0 to 45 degrees is practically preferable.

Table 5 below shows an example of the electro-optical characteristics of the inorganic alignment film (SiO oblique deposition film). The phase difference δ (R
measurement was performed using an automatic birefringence meter of Oak Co., Ltd., and the value of the phase difference exceeded λ / 4, so that He-Ne was used.
The measurement was performed using two wavelengths of [632.8 nm] and a semiconductor laser light source [780 nm].

[0123]

Each FLC shows a phase difference of about half of the used optical wavelength, and it can be seen that the FLC has a specification capable of rotating the polarization plane of the incident light by about 90 degrees.

Further, by adjusting the cell gap in this SiO oblique deposition cell, wobbling cells having various phase differences were produced. The results at a measurement wavelength of 632.8 nm are shown in Table 6 below. When these data are plotted, a substantially linear relationship is obtained as shown in FIG. 22, indicating that the phase difference can be arbitrarily set by gap control. These cells were used for studying the range of the phase difference described above.

[0126]

[0127]

As a driving method for these ferroelectric liquid crystal elements, a conventional general FLC driving method can be applied. In FIG.
One example of a driving waveform of a frame and two fields is shown.

FIG. 23A shows a pulse driving method with a reset pulse, in which a reset pulse is applied immediately before writing to maintain an electrical neutral condition in a field. It is difficult to apply. In addition to FLC, A
Can also be used for FLC.

FIG. 23B shows a pulse driving without a reset pulse, which is a method for maintaining an electrical neutral condition within one frame. In addition to FLC, it can be used for AFLC.

FIG. 23C shows a square-wave drive method in which the electrical neutral condition is maintained in one frame. The DC voltage is applied for a longer time than in the pulse drive, but the device is insulated. If the reliability is high, the driving method is highly reliable. FL
In addition to C, it can be used for AFLC and electromigration type smectic A.

High-speed response of FLC: The switching characteristics according to the above drive waveforms are shown in Table 5 above. Both the rising (10-90% T) and falling (90-10% T) show a high-speed response on the order of μsec, guarantee a sufficient response within one field, and provide an effective response at the video rate. The picture shifting effect is achieved for the first time.

Particularly, in wobbling (picture element shifting),
It is preferable that the response time between the rise time and the fall time is 1/3 or less of the field time, and that the ratio between the rise time and the fall time does not exceed twice.

In this respect, when a nematic liquid crystal is used,
Even with a high-speed device, the rise time when applying an electric field is relatively short, but the fall time when off is long, so that switching within the field is not sufficient, and an effective picture element shifting effect cannot be obtained. In a twisted nematic picture element shifting element, the rise + fall time at a transmittance change of 0 to 90% is a minimum of about 15 msec (room temperature).
It is very difficult to realize even the 2: 1 line interlaced scanning method (1/60 second (16.7 ms) per field), and if the number of frames is the same and the 4: 1 line interlaced scanning method is applied,
It is 1/120 second (8.3 ms) per field, and cannot follow at all. In this respect, the picture element shifting method using the ferroelectric liquid crystal element is effective because the switching time is shorter than that of the TN liquid crystal. Incidentally, the rise and fall time of the ferroelectric liquid crystal element is on the order of μsec, and the slowest one is several milliseconds or less.

Table 7 below shows a comparison of the response time of various liquid crystals. The response speed of the liquid crystal usable in the present invention is extremely high.

[2] Birefringent transparent substrate that shifts the optical axis depending on the polarization direction of incident light (a) Equivalently uniaxial extraordinary optical axis 10 is on the same plane as Z axis as shown in FIG. Element that is not parallel to the axis.

For example, the deviation L of the optical axis on the quartz plate is calculated by the following equation. As shown in FIG. 24, the angle between the extraordinary optical axis 10 of the birefringent transparent medium 4 and the optical axis of the wobbling optical system is β, and the thickness of the quartz plate 4 is d. Here, the refractive index n _e of the refractive index n _o and extraordinary light of ordinary light of the quartz plate 4, n _e = 1.5533
6, is a n _o = 1.54425. Here, 0.7 inch, 1
In order to increase the resolution of the active matrix TN liquid crystal display of 0.3000 pixels in the vertical direction, L = 24.5 μm
Β were set to 45 degrees and d was set to 4.17 mm.

[0138]

(Equation 2)

Here, the effective range of β for expressing the deviation L of the optical axis was 10 to 80 degrees. This shift of the optical axis differs depending on the constituent pixel pitch described later. The following method (b) can also be applied as a method of shifting the optical axis using a polarization switch.

(B) An element in which the surface of the substrate through which light is transmitted is not parallel, and the apparent extraordinary optical axis is parallel or perpendicular to a plane perpendicular to both planes.

A wedge-type nematic liquid crystal cell is constructed as shown in FIG. The cell 34 is formed by using the polyethylene terephthalate (PET) film 30 as a spacer and the two substrates 31 and 32.
The liquid crystal 33 is fixed between the substrates by an angle α.
Has been injected.

The cell fabricated here has an ordinary light per 27 mm,
It was designed such that the deviation L of the optical axis from the extraordinary light was 30.7 μm.

Nematic liquid crystal used: ZL manufactured by Merck
_{I-2008-000 n e = 1.707 n} o = 1.517 ( Note) Merck & Co., Inc. measurements

Orientation direction, alignment direction of liquid crystal and optical properties: A polyimide rubbing film (Ube U-varnish) having a small pretilt angle was used as an alignment film in order to maximize the birefringence of the liquid crystal. . The pretilt angle is less than about 1 degree as measured.

The rubbing was performed in one direction, and the direction was indicated by an arrow 35 in the wedge type cell as shown in FIGS. 26 and 27. In addition, the combination of orientations is parallel orientation in type 1,
In type 2, anti-parallel alignment was used. After assembling the cell, nematic liquid crystal was injected, and the periphery was sealed with an adhesive.

Here, if the refractive index is n _i , the angle of the wedge is αrad, and the distance from the cell to the screen is 1,
Deviation from the optical axis becomes D _i. The refractive index _ni is given by the following equation.

[0147]

(Equation 3)

In this calculation, if l = 27 mm,
The _{D i = D e -D o =} 30.7μm. Also, in fact, l
= 6450 mm, the results in Table 8 below were obtained.

[0149]

In the above description, liquid crystal is used as the wedge-type optical element. Alternatively, a birefringent medium can be formed by injection molding of a resin having a large birefringence such as polycarbonate or lamination of films. The optical axis of the extraordinary light in this case is the same as that of the liquid crystal.

The general polycarbonate molecular structure of, for example, a polycarbonate film that can be used as a birefringent medium is as follows.

Bisphenol A type

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The polycarbonate resin having the above structure was placed in a mini-max molding machine (model indicated by 80 in FIG. 28) to produce a wedge-shaped polycarbonate plate 81. That is, the polycarbonate resin was melted at about 300 ° C. and injection-molded manually at a mold temperature of 60 ° C. Consideration is given to lowering the mold temperature during molding, increasing the melt viscosity, and making the orientation of the polycarbonate molecules sufficient. The relationship between melt viscosity, molecular orientation and birefringence of polycarbonate has been reported by Nagai et al. ("Melt Viscosity and Flow Birefringence of Polyca").
rbonate "J. Appl. Polym. Sci., Vol.44 (1992) pp.1171
-1177).

The used mold had a mirror-finished surface of chrome, and the shape of the mold was as shown in FIG.
It has dimensions of 15mm x 20mm. The obtained wedge-shaped polycarbonate 81 had an inclination α of 24 degrees, and could give an optical axis shift of 40 μm per 27 mm.

Next, the above-mentioned liquid crystal optical device according to the present invention will be described more specifically.

Driving Method and Operation for Higher Resolution of Liquid Crystal Display Element In the NTSC 2: 1 interlaced scanning method, a complete screen (one frame) can be formed in two fields. Then, in the first (odd) field and the second (even) field,
They interpolate each other for vertical position information,
This is a method of maintaining the resolution by increasing the number of fields per second. However, when the number of vertical pixels is small, as in the case of a liquid crystal display device, the odd field and the even field are overwritten on the same scanning line, thereby lowering the inherent resolution.

Here, picture elements are shifted in synchronization with the odd and even fields, and the resolution in the vertical direction is increased by applying the afterimage effect by high-speed image replacement. The shift amount of the picture element shift will be described below. Actually, the liquid crystal has a dot-sequential scanning or a line-sequential scanning, and is scanned in time series. However, in this description, the liquid crystal is treated at the same time so that the principle can be easily understood.

In the case of a monochrome display element, a three-plate color display element or a color sequential display element:
Since one switching element corresponds to one picture element, the picture element of the optical axis is simply shifted by half the distance between the centers of gravity in the picture element shifting direction (center-to-center distance between constituent display pixels) in one picture element. Due to the shift in the direction, the resolution is increased, and at the same time, a non-display portion (for example, a black matrix) between pixels becomes less noticeable. However, the shift need not be exactly half the distance between the centroid points of the picture elements.

That is, as shown in FIG. 29, the effective shift amount differs depending on the difference in the aperture size between the black matrix portion and the constituent pixel portion. When the black matrix portion is the same as or larger than the constituent pixel aperture, a shift (a) of a half of the constituent pixel pitch in the direction in which it is desired to increase the resolution is optimal, but the tolerance is recognized by the shift of the pixel position. Required half of the aperture of the constituent pixel. Further, when the black matrix portion is smaller than the constituent pixel aperture, at least the shift of the length of the black matrix portion is effective (b, c).

With respect to the length component in the picture element shifting direction, the length of the black matrix portion is L _B , and the aperture of the constituent pixel is L _A.
Then, the pixel pitch is L _P = L _A + L _B , and the pixel shift amount L is Min (L _B , L _A / 2) ≦ L ≦ Max (L _P −L _B , L
Represented by _P -L _A / 2).

[0161] Expressed this equation by using the L _P and _{L A, Min (L P -L} A, L A / 2) ≦ L ≦ Max (L A, L
The _P -L _A / 2). Note that Min (x, y), Max in the above equations
(x, y) is a function that gives a small value and a large value of x and y, respectively.

If the picture elements are shifted in the vertical direction as in the example here, the resolution is increased in the vertical direction as shown in FIG. Similarly, if the picture elements are shifted in the horizontal direction, the resolution in the horizontal direction is increased (FIG. 31). Further, if the picture elements are shifted in an oblique direction, the resolution in the vertical and horizontal directions is increased (FIG. 32).

In the case of a color liquid crystal display device having a color filter: In a normal color display device, one picture element is constituted by a trio of R, G, and B color filters. R,
The arrangement method of G and B includes an in-line arrangement (FIG. 33), a delta arrangement (FIG. 34), and the like. Here, the shift amount of the optical axis is one of the distance between the nearest RGB trio area and the center of gravity in the pixel shifting direction. /
What is necessary is just to make it 2 length.

The picture element shifting direction of such a picture element shifting element can be improved not only in the vertical direction but also in the horizontal or oblique direction by two-dimensional picture element shifting, so that the resolution in the shifted direction can be improved. Furthermore, the picture element shift range is
Picture element shifting direction configuration pixel diameter L _A for the length component to that of the RGB pixel trio, by the length of the black matrix portion and L _B, be the same conditions as monochromatic display element having the above-described Can be.

The range of the number of drive electrode divisions in the picture element shifting operation:
In principle, a picture element shift synchronized with each switching per pixel is required. In this case, in the case of point sequential scanning, picture element shifting elements for the number of pixels are required, such as a matrix of thin film transistors (TFTs). Further, in the case of line sequential scanning, it is necessary to divide the electrodes into the number of horizontal scanning lines.

Therefore, when the number of horizontal scanning lines of the display element to be increased in resolution is assumed to be N, it is ideal to divide the transparent electrode into 1 / N in the vertical direction during line-sequential scanning. But,
In order to increase the resolution, a picture element shifting element equivalent in cost is required. Therefore, the present inventor considered that it is possible to reduce the upper limit of the electrode division by the human factor to reduce the cost, and conducted the following experiment.

When the switching timing of the ferroelectric liquid crystal element was determined in synchronization with the vertical synchronizing signal in combination with the above-described TFT color liquid crystal display element, the switching of the FLC element on the entire panel was performed without considering the time-series data. Even so, about 1/4 in the vertical direction of the panel was increased in resolution from 240 TV lines to 370 TV lines.

From this experiment, it has been found that high resolution is effective even in the vertical division up to about 1/4.
That is, in order to increase the resolution, the picture element shifting element combined with the display element having the number N of horizontal scanning lines is divided into N divided in the vertical direction.
One division is sufficient, but in order to increase the resolution of the entire panel, N division to three divisions are preferable. Further, considering electrode processing accuracy, cost, etc., N / 2 or (N + 1)
/ 2 or less is preferable.

Specific Example of Higher Resolution of FLC Picture Shifting Element Using Five-Division Electrode Configuration: FIG. 35 shows an example of a combination of division electrodes. This divided electrode is a transparent electrode (I
TO) 13 and 14 were formed, and the electrodes were etched so as to divide them into five. 10μ distance between ITO electrodes (etched part)
m. It is necessary that the distance between the electrodes is larger than the cell gap (further shorter than the non-display portion) in order to prevent dielectric breakdown due to a potential difference between the electrodes, that is, withstand voltage and the like.
Here, the cell gap was 1 μm to 3.0 μm. It is easily understood that the combination of the divided electrodes may be such that one side may be a common electrode and both sides may be a divided electrode.

Further, an SiO alignment film is used as the alignment film, and the cell assembling method and the liquid crystal injection method are the same as those in the case of the monopolar cell. The liquid crystal alignment direction was set in consideration of the picture element shifting direction.

Synchronization signal of picture element shifting element: Interlaced scanning method (interlace) For a moving image, for example, 24 frames per second for a movie, 25 frames per second for a television
You have sent 30 or 30 images. However, at 24 to 30 sheets per second, flicker interference is so great that it can be used continuously.
For this reason, in a movie, one frame is irradiated twice, and 48 frames are repeated every second. In a television, the number of repetitions per second is increased without increasing the transmission bandwidth by using an interlaced scanning method. The Japanese standard uses a 2: 1 line interlaced scanning method.

That is, as shown in FIG. 36, the scanning started from the point a reaches the point b in N / 2 horizontal scans, moves to the point c in the vertical flyback period, and further N / 2 horizontal scans. The scanning reaches the point d, and returns to the point a again in the vertical baseline period. The period from d to b is called a first (odd) field, and the period from b to d is called a second (even) field. In the 2: 1 line interlaced scanning method, a complete screen (one frame) is formed in two fields. In addition, there is a 3: 1 and 5: 1 interlaced scanning method.

When displaying a screen in line-sequential scanning of the NTSC system or the like, there is little problem with the resolution of the current CRT because it is analog.
For a display having discrete pixels such as a pixel array, a considerable amount of horizontal position information is lost due to a discrete pixel arrangement, information of a scanning line is lost, or positional resolution of a luminance signal is reduced ( That is, the resolution of the display is reduced) as described above.

Here, a specific method of setting the timing of picture element shifting (wobbling) will be described. TV signal, Figure 37
As shown in (1), each field is composed of a luminance signal, a vertical synchronization pulse, a horizontal synchronization pulse, a color signal, and a color synchronization pulse. Here, a vertical synchronization pulse of an odd field (first field) and an even field (second field) are detected, a synchronization signal is sent to the FLC driver from this, and then a delay is given to each channel in the driver. What is necessary is just to send a drive waveform to an FLC cell.

Synchronization of divided FLC element, FLC drive circuit and video signal processing system: FIG. 38 shows the configuration of the electrodes, the connection of the drive circuit, and the video signal processing system and the method of synchronization. That is, by the video signal processing device 40,
The sync pulse and the RGB signal of the odd field (first field) and the even field (second field) are supplied to the display element 2, and at the same time, the vertical sync pulse of each field is detected and the sync signal is sent to the FLC driver 41. Subsequently, a drive waveform with a delay applied to each channel in the driver 41 is sent to the FLC cell 3.

The driving waveform was as shown in FIG. 39, the entire ITO side was used as a common electrode, and the five-divided electrode side was divided into Ch1 to Ch5, and pulse driving was performed as shown. That is, the time of one field is divided into five parts based on the detected vertical synchronizing signal, and each channel is sequentially delayed.
Therefore, it is important that the driving of the TN liquid crystal display element 2 and the driving of the FLC element 3 are synchronized. Note that a general FLC driving method and rectangular wave driving can be applied to these driving waveforms.

Further, a specific method for changing the direction of shifting the picture element will be described. A method for increasing the resolution in the vertical direction of the display element 2 (FIG. 40) and a method for increasing the resolution in the vertical and horizontal directions (FIG. 41) will be described. As a result, it was confirmed that the resolution was improved in the respective directions.

In the above-mentioned five-division FLC element, a study was made on a high resolution in consideration of drive conditions, optical arrangement, and picture element shift amount. As a result, a 0.7-inch, 130,000-pixel active matrix TN liquid crystal display panel was used. The resolution was increased from 240 TV lines to 370 TV lines or more over the entire surface, and the black matrix as a non-display portion became inconspicuous, and a high-resolution and smooth screen was achieved.

Other Structural Improvements: In the above example,
The chiral smectic liquid crystal element 3 was manufactured using the transparent glass substrates 20 and 21 as shown in FIG. 42, but in order to further reduce the cost, volume and weight, one of the transparent substrates was used as shown in FIGS. 20 can be replaced with a quartz plate 4, and a transparent electrode 13 and an alignment film 22 can be attached to the quartz plate to integrate with the chiral smectic liquid crystal element 3. Further, reflection can be suppressed by matching the refractive index, and the light transmittance can be improved. In FIG. 44, a reflection plate 42 is further provided on the display element 2 side,
The display performance has been improved.

These high resolution techniques can be used regardless of the mode such as a direct view type, a reflection type and a projection type. this house,
FIGS. 45 to 47 show three examples of the projection type display, respectively.

In the example of FIG. 45, the light from the halogen lamp 17 is led to the display element 2 as a backlight through the cold filter 43, and after the above-described wobbling processing, the lens system
An image is projected from 44 to a screen 45.

FIG. 46 shows a mirror type display, in which a light source is shown.
The light from 17 passes through a filter 46, is separated into light of a predetermined wavelength (R, G, B) by each dichroic mirror 47, and is incident on each wobbling element from a condenser lens 48, where it is wobbled and then again. The images are synthesized and projected on the screen 45.

FIG. 47 shows a prism type display,
This is basically the same as that in FIG. 46 except that the light of each wavelength is synthesized via the dichroic prism 48.

The above-described high resolution technology is used in the visible light wavelength range for application as a display.

[0185] applying the invention to the image pickup element, placing the wobbling element 7 described above in the optical path connecting the not limited to the display device 2 described above, an imaging element such as a CCD composed of discrete pixels and the object The case also applies.

An image pickup apparatus 71 according to the present invention shown in FIGS.
It is preferable that the above-described various conditions, principles, and descriptions of the display device be similarly adopted. In the following, the same components as those of the display device described above will not be particularly described repeatedly, but, in comparison, those specific to the imaging device will be mainly described.

When an image pickup device such as a CCD is used, β = 45 in order to increase the resolution of, for example, a 1/3 inch CCD in the horizontal direction, the vertical direction, or the horizontal and vertical directions simultaneously.
By adjusting the thickness d of the quartz plate as a degree, the amount of pixel shift was adjusted. Since the horizontal pitch of the 1/3 inch CCD is 6.35 μm and the vertical pitch is 7.4 μm, the pixel shift amount for increasing the resolution in each direction is as follows.
The pitch may be set to 3.18 μm or 3.7 μm which is about １ ／ of each pitch. Further, in the case of shifting the picture element in the oblique direction, it is necessary to shift the length of the diagonal line of the rectangle having the horizontal and vertical components on each side. In this case, the length may be 4.88 μm.

For example, in order to give a deviation of L = 3.7 μm, β = 45 degrees and d = 0.63 mm. Here, the range of β effective for expressing the deviation L of the optical axis was 10 to 80 degrees.

When using the image sensor, the subject, the polarizer, the FLC device, the birefringent substrate, and the image sensor are arranged in the optical path connecting the object and the image sensor 4 in this order. In this case, the lens system, the iris, and the wavelength limiting filter may be arranged anywhere in the optical path connecting the subject and the image sensor.

As shown in FIGS. 48 and 49, when the switch state of the ferroelectric liquid crystal element 3 is the state 1, the irradiation light component a from the object 50 side passes through the lens 51 and the aperture 52, The light is polarized by the polarizing plate 19 in the direction in which the picture element is shifted. Since the polarization plane of the light and the extraordinary optical axis 8 of the ferroelectric liquid crystal element 3 are parallel, the transmitted light is applied to the quartz plate 4 having birefringence while maintaining the polarization plane. In the quartz plate 4, since the extraordinary optical axis of the quartz is included in the incident polarization plane, the light polarized in the Y-axis direction is refracted in the direction in which the extraordinary optical axis of the quartz plate is inclined, and exits to the air layer again. Being parallel to the optical axis, the deviation of the incident light from the optical axis occurs, and CC
Each picture element of the D imaging device 53 is irradiated.

On the other hand, when the switch state of the ferroelectric liquid crystal element 3 is the state 2, the transmitted light rotates in the direction of the extraordinary optical axis because the polarization plane and the extraordinary optical axis 8 form an angle of about 45 degrees. , Linearly polarized light (Y-axis direction) → elliptically polarized light → circularly polarized light → elliptically polarized light → linearly polarized light (X-axis direction) in the ferroelectric liquid crystal element, and the polarization plane is rotated by 90 degrees from the initial state. Is irradiated.
In the quartz plate 4, since the extraordinary optical axis of the crystal is not included in the plane of polarization of the incident light, the optical axis is maintained without being refracted, exits to the air layer again, and is irradiated on each picture element of the CCD image sensor 53. .
That is, an image of the part a 'of the subject is taken. The shift of the optical axis between the state 1 and the state 2 can be used as the operation principle of the picture element shift.

Due to the ambient temperature of the element, the apparent cone angle deviates from 45 degrees (for example, 45 + γ degrees: where γ is 45> γ).
> −45) In the wobbling operation, if the optical axis of one of the liquid crystal directors in the switch state is ideally aligned parallel or orthogonal to the polarization plane of the polarizing plate, the polarization plane of the transmitted light does not change in this switch state. . In this case,
Since the plane of polarization is not rotated, 100% of the light is refracted in the direction of the extraordinary optical axis of the quartz plate 4, for example, as shown in FIG. At this time, there is almost no component other than the point a.

In the other switch state, since the angle is 45 + γ degrees, when γ is positive, the polarization plane of the transmitted light is rotated by 90 degrees or more, and when γ is negative, the polarization plane is rotated to 90 degrees. do not do. When the polarization plane is completely rotated by 90 degrees, the component of a 'becomes almost 100% as shown in FIG. However, as shown in FIG. 50, when the rotation of the polarization plane deviates from 90 degrees by an angle of γ, the component in the Y-axis direction also increases as a polarization component, so that a slight leak occurs in the adjacent imaging pixels in the Y direction. Occurs. Therefore, in this case, the effect of pixel shifting, which should originally be a high resolution, is slightly reduced.

Therefore, for the same reason as described with reference to FIG. 13, the bisector of the angle formed by the above two switch states forms the angle formed by the polarization plane of the polarizing plate or a line perpendicular to the polarization plane. Ideally, δ should form an angle of 22.5 degrees. By arranging the orientation of the liquid crystal director 8 in this manner, as shown in FIGS. 51 and 52, crosstalk occurs in both switch states, but crosstalk in each switch state is small. In addition, since the sum is smaller than the crosstalk of only one side, it has been found that the effect of high resolution is not reduced.

Here, the range of θ, and the angle δ formed by the bisector of the two-switch state with the polarization plane of light or a line orthogonal thereto are clarified from the following wobbling experimental results.

That is, in the examination of one-sided shaft fixing, θ = 26 to
High resolution of the CCD was confirmed by the wobbling effect in the range of 64 degrees. Furthermore, high resolution with little coloring was achieved in the range of θ = 36 to 54 degrees.

Further, as a result of examining the position of the δ axis in the range of θ = 36 to 54 degrees, it was found that there was almost no coloring at δ = 22.5 ± 10 degrees and high resolution could be achieved. Further, θ = 36
In the range of .about.54 degrees and .delta. = 22.5. ± .5 degrees, cross-talk between fields was reduced, and the contrast ratio between fields was increased.

Note that the resolution evaluation here is performed by taking an image of a lattice evaluation resolution evaluation panel, converting it to a video signal, and then executing a CR.
It was displayed on a T monitor and determined by observation.

FIG. 53 shows a specific arrangement example. In the case of an optical system such as a video camera and a still video camera, since incident light from the outside is not generally polarized, a polarizing plate is inserted between the outside (subject) and the ferroelectric switching element. Regardless of the positional relationship with respect to the aperture. Other optical arrangements include subject-lens-aperture-
The order is a polarizing plate, a ferroelectric switching element, a transparent substrate having uniaxial optical anisotropy, and an imaging element. Examples of the imaging device to be combined here include a CCD, a MOS type device, and the like.
Regardless of its type.

[0200] Unlike the display element, such an image pickup element is a light receiving element, so that the spatial resolution (spatial resolution) of a subject can be improved. Here, since it can be performed in a simultaneous method instead of a sequential method like a display element,
The switching section of the FLC element 3 may operate on the entire surface of the CCD element at the same time, and does not require spatial electrode division of the phase modulation element 3. That is, for example, the pixels of the CCD image sensor also
If there is no deviation of the optical axis because of the discrete, a,
Although there is only the position resolution of b and c, the frame is divided, and the information of a, b and c is first stored in a simultaneous method and then transferred.
In the next field, the position information of a ', b', and c 'is accumulated in a simultaneous manner by shifting the picture elements of the ferroelectric liquid crystal element 3,
By transferring and recombining with the first field, the vertical resolution is doubled.

In particular, in order to improve not only the vertical resolution but also the horizontal resolution, one frame must be further composed of three fields and four fields. This also requires a high-speed response of the ferroelectric liquid crystal element. is there. In the twisted nematic pixel shifting element, the transmittance change is 0 to 90.
% Is a minimum of about 15 msec (room temperature), and it is quite difficult to realize even with NTSC's 2: 1 line interlaced scanning method (1/60 second per field ((16.7 ms)). Furthermore, if the same number of frames is used and the 4: 1 line interlaced scanning method is applied, it is 1/120 seconds (8.3 ms) per field and cannot follow at all. The shift method is effective because the switching time is shorter than that of the TN liquid crystal, and the rise and fall time of the ferroelectric liquid crystal element is on the order of μsec.
ms or less.

In the case of a monochrome image pickup device and a three-plate color image pickup device: since one switching element unit corresponds to one picture element, it is simply a half of the distance between the centers of gravity of one picture element in the resolution improving direction. The resolution is improved by shifting the optical axis in the resolution improving direction. Further, the allowable range is suitably 50% to 150% of the shift length.

In the case of an image pickup device having a color filter:
One picture element is composed of a trio of R, G, and B color filters. The R, G, and B arrangement methods include a delta arrangement, an inline arrangement, and the like. The shift amount of the optical axis in this case is 1/1/3 of the closest distance between the centers of gravity of the R, G, and B trios in the resolution improving direction.
What is necessary is just to make it 2 length. Further, the allowable range is suitably 50 to 150% of the shift length.

Other Structural Improvements: In the above example,
Although the ferroelectric liquid crystal element 3 was manufactured using a substrate different from the quartz plate 4, in order to further reduce the cost, volume, and weight, as shown in FIG. A film (both not shown) is attached, and a picture element shift element integrated with the ferroelectric liquid crystal element 3 is arranged via a protective glass substrate 60 on the entire surface of the CCD (A), or a quartz plate is omitted. The side can be glued and protected (B). FIG. 3C shows the CCD 53 and the quartz plate 4 integrated,
The LC element 3 has the same configuration as the above-described example.

A specific example of mounting these cells on a video camera: Handycam TR-1 (manufactured by Sony Corporation) will be described. First, an infrared cut filter and a low-pass filter that can be used for the camera will be described.

[1] In the case of normal visible light imaging A semiconductor imaging device such as a CCD imaging device has a sensitivity range of
It extends to 380-1200nm. When a normal visible light image is taken, the image is taken up to a near-infrared light region that cannot be sensed by human eyes, which has an adverse effect on the image. Therefore, it is necessary to insert the infrared cut filter 61 between the subject 50 and the CCD 53 as shown in FIG.

Here, an example is shown in which an infrared cut filter (which cuts a wavelength of 700 nm or more) 61 is combined with the picture element shifting element. In addition, only a quartz plate used for a wobbling element does not sufficiently cut high-frequency components, and therefore requires an optical low-pass filter. Therefore, a quartz low-pass filter (a plurality of quartz plates) for seven-point blurring, which is generally used in a high-quality CCD video camera, is used.
Consists of 64. ) Was incorporated (FIGS. 55 and 56).

In this low-pass filter, incident light is made into a two-point blur by utilizing the birefringence in one quartz plate, and a two-point image is formed by laminating another quartz plate rotated around the optical axis. The four-point image is further blurred as a seven-point image by a third quartz plate, so that the low-pass filter characteristics can be improved.

That is, by blurring the incident light in this way, a high spatial frequency component of image information can be removed, and problems such as moire fringes and false color signals can be avoided. However, in the case of a single quartz plate, the high-frequency component can be cut or dispersed only in the y direction, but in the above case, the high-frequency component can be cut or dispersed in both the x and y directions, and the high-frequency component can be cut while maintaining the sensitivity of the low-frequency component. The influence on the image (moire fringe pattern or false color signal generated in the formed image output) can be further reduced.

FIG. 57 shows an implementation example without such a low-pass filter, and FIG. 58 shows an implementation example using the low-pass filter.
It was shown to. In each case, the picture element shifting element (wobbling element) 7 is provided in front of the CCD 53.

When the low-pass filter 64 is used, the first extraordinary optical axis of the low-pass filter is the same as the polarization at the time of wobbling.
When the angle is 30 to 60 °, the effect of the low-pass filter is obtained, but otherwise, the low-pass filter characteristic changes in the field. At this time, by inserting a λ / 4 plate (not shown) between the picture element shifting element 7 and the optical low-pass filter, a difference in low-pass filter characteristics between fields can be reduced, and the low-pass filter characteristics can be sufficiently exhibited. Become like

FIG. 59 shows a color separation camera system using three CCDs. However, CCD drive circuit,
The wobbling element drive circuit is omitted.

[2] Infrared Light Imaging Using the near infrared light region of a semiconductor image pickup device such as a CCD image pickup device, only the near infrared light region that cannot be sensed by human eyes can be picked up. . In this case, there is no need to insert an infrared cut filter.

In this case, in order to image only infrared light, it is necessary to insert a visible light cut filter (cut at 760 nm or less) between the subject and the CCD. This makes it possible to image the temperature distribution and the like of the subject. Since the imaging wavelength at this time extends to 700 to 1200 nm, the phase difference of the picture element shifting element needs to be half the wavelength of 350 to 600 nm.

Next, another embodiment of the present invention using a birefringent medium (phase compensating medium) for phase adjustment in the above-described embodiment will be described.

According to the embodiment shown below, the range from 400 nm to 7
By inserting a phase compensation medium that rotates the polarization plane by 90 degrees in the wavelength range of 00 nm into the element, crosstalk in both switch states can be further reduced, and higher resolution can be achieved. Specific examples will be described.

[0217] The implementation view 60 of the phase compensation medium, wobbling device that implements the phase compensation medium 100
107 and a liquid crystal optical display device 101 are shown.

In FIG. 60A, a ferroelectric liquid crystal (FLC)
The slow axis 108 of the element 3 is substantially orthogonal to the slow axis 118 of the phase compensation medium 100 having the same phase difference as the FLC element 3. As a result, the phase difference generated in the FLC element 3 can be canceled by the phase compensation medium 100 having a phase opposite to that of the FLC element 3.
Is incident on the birefringent medium 4 for shifting the optical axis, apparently parallel to the extraordinary optical axis 10 whose polarization plane is inclined at β, without being rotated by the polarization plane. As a result, the optical axis is shifted.

In FIG. 60B, the slow axis 10 of the FLC element 3 is
8 changes to state 2 by a switch associated with the application of an electric field to the FLC element 3. As a result, the new slow axis synthesized from the slow axis 108 of the FLC element 3 and the slow axis 118 of the phase compensation medium 100 has an inclination of 45 degrees with respect to the Y axis. Therefore, the plane of polarization is rotated by 90 degrees due to the synthesized slow axis,
The polarization plane is parallel to the Z axis, and apparently perpendicularly enters the extraordinary optical axis 10 whose polarization plane is inclined to β into the birefringent medium 4 for shifting the optical axis, so that the optical axis does not shift.

Here, assuming that the apparent cone angle of FLC is θ, FIG. 61A shows the relationship between the optical axes. In this figure, P
Reference numeral 1 denotes the direction of the polarization plane parallel to the Y axis or the polarization axis of the polarizing plate. P2 is an axis parallel to the X axis, and the extraordinary optical axis 10 whose polarization plane in the birefringent medium for shifting the optical axis is inclined to β.
And orthogonal. LC1 and LC2 are FLC elements 3
In each of the switch states, the slow axis 108 and the PC
A zero slow axis 118 is shown.

The relationship between the optical axes here is such that the slow axes LC1 and LC2 of the respective switch states of the FLC element are line-symmetric with respect to the axis of the incident polarization plane P1. Then, by arranging the slow axis PC of the phase compensating medium so as to be substantially orthogonal to one switch state, for example, LC1, the polarization plane P1 becomes L under the influence of LC1 of the FLC element.
Although rotated toward the axis of C1, it is canceled by the PC having substantially the same phase difference as LC1, and is returned to the original polarization plane P1. By switching the FLC element by applying an electric field and setting the slow axis to LC2, the polarization plane P1 rotates toward the axis of LC2, and is further affected by the slow axis PC of the phase compensation medium, and the polarization plane further increases. The polarization plane P1 is rotated toward the axis side of the slow axis PC, and as a result, the polarization plane P1 is rotated to the polarization plane P2 in total of the FLC element and the phase compensation medium. That is, LC2 and PC
Is the slow axis (LC2 + PC) of P1 and just π /
4 angles.

When the same element as the FLC element 3 used is used as the phase compensation medium 100, the fluctuation of the cone angle due to a temperature change or the like can be further absorbed. FIG. 61B shows this principle. That is, a method using a second FLC element instead of the phase compensation film shown in FIG. The slow axis of the second FLC for phase compensation is set to PC
LC1 and PCLC2.

Here, first, the memory state of the second FLC or PCLC1 is set by applying a voltage, and the first FLC is changed to PCLC1.
The element 3 is switched between LC1 and LC2 by applying an electric field. Thus, the same effect as that obtained by using the phase compensation film of FIG. 61A can be obtained. Further, since the same wavelength dependency of the birefringence can be used in the first FLC and the second FLC, it can be seen that the effect of the phase compensation is excellent.

Here, when the temperature environment of the element changes, the apparent cone angle changes as shown in FIGS.
In the configuration shown in FIG. 61A, the change in the cone angle causes light leakage between the odd field and the even field during wobbling, that is, crosstalk. However, FIG.
In (B), the arrangement of the slow axis of the second FLC element undergoes the same temperature change, so that the angle between LC1 and PCLC1 is always π / 2, and the phase difference is canceled. On the other hand, L
Slow axis synthesized from C2 and PCLC1 (LC2 + PC
LC1) always forms an angle of π / 4 with respect to P1 and P2, and the temperature dependence of the phase difference slightly remains, but the crosstalk is reduced.

In this example, CS-10 is used as the FLC element.
A 14 liquid crystal / SiO oblique deposition antiparallel cell was used. The cell gap is 2.1 μm, and the phase difference at 632.8 nm is 263.69.
nm. The optical system for evaluating the amount of crosstalk is the same as that shown in FIG.

First, FIG. 63 shows a spectrum when the FLC elements are arranged as shown in FIG. 62 and are switched by applying an electric field. According to this, in the LC1 state, the polarized light from the polarizer passes through the analyzer without being rotated by the polarization plane. On the other hand, in the LC2 state, the polarized light from the polarizer rotates its plane of polarization, and is absorbed by the analyzer according to the rotation, and the amount of transmitted light changes. In this case, the wavelength component of about 550 nm is just rotated by 90 degrees in the plane of polarization.

Further, in order to improve this characteristic, a phase compensation film 100 was arranged as shown in FIG. The optical system of the measurement system is as shown in FIG. FIG. 65 shows the spectrum of the optical system. According to this, in the switching state of LC1, since the phase difference is canceled by the PC, the plane of polarization is not rotated. Therefore, as shown in FIG. 65, the analyzer is almost completely covered from 450 to 700 nm. To Penetrate. On the other hand, in LC2, the plane of polarization is rotated by 90 degrees, and the plane of polarization is absorbed because it is orthogonal to the analyzer, and the transmittance becomes almost zero over almost the entire range from 450 to 700 nm.

Next, the use of the phase-compensated wobbling element was examined to increase the resolution.

First, the results without phase compensation are shown in Table 9 below. According to this, the effect of increasing the resolution is visually confirmed, but the resolution is increased up to about 390 lines, and the screen is colored due to a change in the gap.

[0230]

[0231]

On the other hand, a phase compensation film 100 having a phase difference equivalent to the phase difference of the FLC element, here, a polycarbonate film (for example, manufactured by Nitto Denko Corporation) was selected. For example, a device having a gap of 2.1 μm uses a 260 nm phase compensation film.

[0233] The results are shown in Table 10 below, where the coloring of the screen is reduced, the gap range for providing higher resolution is expanded,
Further, crosstalk due to the optical axis shift in the first field and the second field is reduced, and the contrast of each field is improved, so that a higher resolution can be obtained as compared with the case without the phase compensation. Was confirmed.

[0234]

[0235]

This result indicates that, by performing phase compensation on the wobbling element, if the FLC element having a phase difference of 160 to 380 nm measured using a light source of 632.8 nm is used, high resolution can be obtained without coloring. It shows what can be achieved. In other words, it can be seen that a film having the same phase difference in the range of 160 to 380 nm should be selected as the phase compensation film to be combined with the FLC element.

As described above, since crosstalk between fields during wobbling is reduced by the phase compensation and the contrast ratio between the fields is increased, it can be seen that the resolution is further improved.

As shown in FIG. 61C, for example, as shown in FIG. 61C, the phase is canceled by the PC in the switch state LC1, so that the birefringence is small and the direction of the slow axis has little effect. However, the switch state LC
2, the position of LC2 + PC (P
1, 45 degrees with respect to P2), but with the deviation of the alignment processing direction and the change of the cone angle due to the temperature change, etc., the synthesized slow axis LC2 + PC
Comes off 45 degrees. Since the influence of this shift is so large that the birefringence cannot be ignored, the same study as described above was conducted.

That is, in each of the switch states after phase compensation in the two switch states of the liquid crystal in the phase-compensated phase modulation optical element, the two axes between the slow axis of birefringence having a large absolute value and P1 or P2. Assuming that the angle formed by the equal line with the polarization plane (P1) of the light from the display element or the line (P2) orthogonal thereto is δ1, the result of examining the position of the δ axis in the range of θ = 36 to 54 degrees. , Δ1 = 22.5 ± 10 degrees, no coloration, crosstalk between fields was reduced, and the contrast ratio between fields was increased, so that the resolution was further improved.

Here, besides polycarbonate, a colorless and transparent polymer film such as an aromatic polyester shown below can be used as the phase compensation film.

Usable phase compensation film materials: polystyrene resin, styrene-maleic anhydride copolymer, AS
Resin (acrylonitrile-styrene copolymer); methacrylic resin; vinyl acetate resin, ethylene-vinyl acetate copolymer; cellulosic plastics, especially cellulose acetate (Cell-OCOCH ₃ ), cellulose acetate propionate (Cell-OCOCH) _3, -OCOC ₂ H _5), cellulose acetate butyrate _{(Cell-OCOCH 3, -OCOC 3} H 7); polyamide resins represented by nylon; polycarbonate; modified polyphenylene ether; thermoplastic polyester resin (PET: polyethylene terephthalate, PBT: polybutylene terephthalate, PCT: polycyclohexane terephthalate,
PBN: polybutylene naphthalate); polyphenylene sulfide (polythioether sulfone, polythioether ketone, polysulfide sulfone, polysulfide sulfone ketone); polysulfone; amorphous polyarylate; polyether sulfone; polyetherimide; polyether ketone; polyamideimide; Polyimide; further, an aromatic polyester-based compound containing a π-electron system among main-chain-type polymer liquid crystals; a side-chain-type polymer liquid crystal, for example, one in which liquid crystal is introduced into acrylate-based side chains.

The common feature is that the molecular structure includes a phenyl group, that is, a π-electron system structure, whereby the wavelength dependence of the refractive index of ordinary light and extraordinary light is similar to that of the FLC element. Therefore, it can be seen that it is preferable for phase compensation in a wide wavelength range. That is, by using a polymer material containing a π-electron system, it is possible to improve crosstalk as an integral amount in a used wavelength range between fields during wobbling as compared with a wobbling element without phase compensation.

The slow axis of these phase compensation films is determined by a stretching operation (inflation method, roll stretching, etc.) in a film forming process (extrusion from a molten state or extrusion from a solution state to a spinning bath) or film formation. It is determined by a method of actively promoting molecular orientation by a subsequent stretching operation (roll stretching or the like). That is, when electrons move easily in the direction parallel to the molecular chain (such as polycarbonate and aromatic polyester), the molecular orientation axis becomes almost a slow axis.
On the other hand, when electrons move easily in the direction perpendicular to the molecular chains (such as polystyrene), the direction substantially perpendicular to the molecular orientation axis is the slow axis.

The polarizing plate usually has a protective film made of T
Although AC (triacetylcellulose) is stuck, in this case, there is no improvement in crosstalk because there is no phase difference. When applied to wobbling, it is necessary to add a phase compensator satisfying the above characteristics to the polarizing plate.

Further, as shown by the imaginary line in FIG. 60, even if the phase compensation film 100 was replaced between the display element 2 and the FLC element 3, the same effect as described above was obtained. Or,
As described later, the phase compensation film 100 is
And the birefringent medium 4, and the display element 2 and the FLC element 3
It can also be arranged on both sides. In this case, it is considered that the phase adjustment can be further changed.

FIG. 66 shows an embodiment in which the FLC element 3 shown in FIG. 60 and the phase compensation FLC element 110 are combined for phase compensation.

Here, as the combined phase compensation FLC element 110, an element having the same specifications as the switching FLC element 3 was used. The optical axis is arranged as shown in FIG. 61 (B). At this time, in order to maintain the state 1 of the phase compensation FLC element 110, the FLC memory state or the voltage applied state can be used.

Considering the temperature dependence of the cone angle of the CS-1014 liquid crystal shown in FIG. 4, a gradual change in the cone angle from 0 ° C. to 45 ° C. and a sharp change at 45 ° C. or more are observed. Therefore, when confirmed by the projector method shown in FIG. 79 described later, the environmental temperature of the FLC element was initially about 23 ° C.
Approximately 45 ° C. was reached after 3 minutes. Further, when the outside air temperature was examined at 30 ° C., the FLC ambient temperature reached 50 ° C.

In the case where a polycarbonate film is used as the phase compensation medium, the resolution is determined from the original 240 TV lines of the liquid crystal display element until the ambient temperature of the FLC element reaches 45 ° C.
High resolution up to 450 to 480 TV lines was confirmed. However, when the FLC element ambient temperature was 50 ° C., the resolution was improved to about 370 to 380 TV lines.

On the other hand, when the FLC switching element is combined with the FLC element 110 having the same specifications as the FLC switching element, the resolution is changed from 240 TV lines of the original liquid crystal display element to 450 dpi when the environmental temperature of the FLC element is up to 45 ° C. ~ 480 TV
High resolution up to the book was confirmed. Further, when the FLC element ambient temperature was 50 ° C., a high resolution of about 400 to 430 TV was achieved. That is, it was confirmed that a decrease in resolution due to a temperature change can be suppressed.

Even if the phase compensation FLC element 110 was replaced between the display element 2 and the switching FLC element 3, the same effect as described above was obtained.

In the above embodiment, the phase compensation medium 100 or
The case where 110 is arranged before or after the FLC element 3 has been described. For example, a case where the phase compensation film is arranged before and after the FLC element 3 at the same time will be described.

As a phase compensation film, the optical axes of the polycarbonate films disposed before and after the FLC element 3 were maintained, and the sum of the phase differences of these films was made substantially the same as the phase difference of the FLC element. Here, the gap is 2.1 μm
And a polycarbonate film having a phase difference of 100 nm and 160 nm.

As a result, it was confirmed that the resolution was increased to 450 to 480 TV lines as in the case of one phase compensation film.

Further, a liquid crystal display element, particularly, an STN (Super
Twisted Nematic) The phase compensation method used in the liquid crystal display device can also be applied. This is described in the Handbook of Liquid Crystal Display Manufacturing Technology (published by Takashi Shimada, published by Science Forum Co., Ltd.). As described in 36-37, a phase compensator is superimposed on an STN liquid crystal panel sandwiched between glass substrates, and furthermore, they are sandwiched by polarizing plates from both sides, so that the coloring of the screen, which is a drawback of the STN method, is achieved. It has been resolved. This phase compensator may be used in large numbers, because it is more accurate to stack several plates with different optical axis directions.

[0256] Further, regarding the superposition of a plurality of sheets, see the above-mentioned "Liquid Crystal Display Manufacturing Technology Handbook" (edited by Takashi Shimada, published by Science Forum Co., Ltd.), p.
As described in JP-A-84-185, the birefringence (Δn) of the retardation film generally depends on the wavelength λ as in the following equation. Δn (λ) = A + B / (λ ² −λ _O ² ) (A and B are constants, λ _O is an absorption edge)

Since this wavelength dispersion differs depending on the material of the film, a large number of sheets were bonded by adjusting the bonding angle of the slow axis by combining different materials (for example, polycarbonate and polypropylene or polycarbonate and polyvinyl alcohol). It is possible to control the wavelength dispersion characteristics of the phase compensation film. This is the phase compensation technique used in the conventional STN.

By applying such a technique to the phase compensation medium in the wobbling element according to the present invention,
It is possible to match the birefringence wavelength dispersion characteristics of the phase compensation film with the birefringence wavelength dispersion characteristics of the liquid crystal material used for the wobbling element, whereby crosstalk of the wobbling element can be reduced.

In the example described above, the case where the display element has polarized light has been described. However, the present invention can be applied to a case of a non-polarized display element.

That is, in the case of a plasma display, an LED display, or the like (ie, when the degree of polarization of light from a display pixel is small), a polarizing plate is provided in the optical path connecting the display element and the picture element shifting element to make the light polarized. Should be inserted. The optical arrangement conditions are the same as in the case of the liquid crystal display element.

Next, a liquid crystal optical device incorporating the above-described phase compensation medium will be described more specifically.

The drive waveform shown in FIG. 39 can be applied to the drive waveform when the phase compensation is performed.
The driving waveform shown in FIG. In the wobbling cell, a polyimide alignment film JALS-1524 manufactured by Nippon Synthetic Rubber Co. was used as the alignment film.

In the method of forming the polyimide alignment film, a polyimide solution was applied by a spin casting method or a gravure printing method, and after baking, an alignment film having a thickness of 80 nm was obtained. The rubbing direction is different from the case without phase compensation as described below.

That is, in FIG. 67, the upper surface is on the side of the polyimide alignment film, but the alignment processing direction indicated by the arrow is the same as that in the case where the pixel is shifted horizontally or vertically with respect to the screen as shown in FIG. Parallel or vertical.
Further, in the case of the oblique displacement, it is preferable to be parallel to the diagonal direction of the screen.

Further, the direction of the cell set is such that the rubbing direction is parallel or anti-parallel on the alignment film side, and a gap of about 2 μm is formed using a sealing material in which spacers are dispersed.
And FIG. 68 (A) shows a state in which the upper and lower substrates are joined to assemble a cell, and FIG. 68 (B) shows the relationship between the alignment processing direction and the pixel shifting direction on the upper and lower substrates. Here, the orientation directions after the cell assembly are parallel, but may be antiparallel.

The study was carried out in a case where the pixel shift direction is vertical in a cell in which both substrates face each other in parallel. A phase compensation film manufactured by Nitto Denko Corporation is placed on the upper surface of this cell so as to be perpendicular to the switch state of the ferroelectric liquid crystal director.
The extraordinary optical axes (the phase difference at a wavelength of 632.5 nm was 260 nm) were aligned, and they were attached with an adhesive.

Further, this cell was combined with a TN liquid crystal display element 2 as shown in FIG. 69, and confirmation of higher resolution was performed. In addition, the example of the case of the oblique displacement is also shown in FIG.

Next, an example of the used drive waveform is shown in FIG. This drive waveform is stored in a ferroelectric liquid crystal device during memory.
This is effective for twisting. This is particularly effective when the memory characteristics of the FLC are weak, or when a sufficient effect of rotating the polarization plane cannot be obtained due to the twist of the liquid crystal alignment during the memory.

That is, this drive waveform repeats application of at least two positive pulses and subsequent application of at least two negative pulses. Of the pulses of the same polarity in these pulse applications, the first pulse is applied. The absolute value of
Since the absolute value of the pulse is larger than that of the first pulse, the speed can be increased by the first pulse, and the apparent cone angle can be adjusted by the second pulse. Stability can be improved, and deterioration over time can be prevented. In addition, since the apparent cone angle can be adjusted to 45 ° ± 5 ° by the second pulse, a decrease in the wobbling effect can be suppressed.

In the above-mentioned five-division FLC element, a study was made to increase the resolution in consideration of the drive conditions, the optical arrangement, and the amount of pixel shift. As a result, a 0.7-inch, 130,000-pixel active matrix TN liquid crystal display panel was used. The resolution has been increased from 240 TV lines to 450 TV lines or more over the entire surface, and the black matrix, which is a non-display portion, has become inconspicuous, and a high-resolution and smooth screen has been realized.

FIGS. 71 to 74 show various examples of the arrangement of the phase compensation wobbling element and the position where the phase compensation film 100 is attached.

FIG. 71 shows that the position at which the phase compensation film 100 is adhered to the ferroelectric liquid crystal element 3 and the quartz
FIG. 72 shows a case where the sticking position is between the ferroelectric liquid crystal element 3 and the display element 2. As described above, it is effective to attach the phase compensation film 100 to either the front or rear of the smectic liquid crystal electro-optical element (for example, the FLC element 3).

With respect to the position at which the phase compensation film 100 is attached, in general, in a smectic liquid crystal electro-optical element, the orientation tends to be disordered when the phase compensation film is attached. As shown in FIG. 74, it may be directly attached to a birefringent medium such as the quartz plate 4 or the display element 2. In this case, the performance and the yield can be improved without causing disturbance of the liquid crystal alignment. Further, it can be attached to the upper surface of the polarizing plate of the TN liquid crystal display element.

In order to improve the transmittance of the wobbling element, as shown in FIG. 75, the space between the birefringent medium (quartz plate 4) and the electro-optical element 3 is changed to the refractive index of the birefringent medium 4 and the glass substrate. It can be attached with an optical adhesive 121 having a refractive index close to the above. With this structure, reflection at the air / quartz plate interface was reduced, and the transmittance was improved.

Other Structural Improvements: In the above example, the chiral smectic liquid crystal element 3 was manufactured using a transparent glass substrate. However, in order to further reduce cost, volume, and weight, as shown in FIG. Can be integrated with the chiral smectic liquid crystal element 3 by attaching a transparent electrode and an alignment film to the crystal plate 4, and at the same time, the reflection can be suppressed by matching the refractive index, and the light transmittance can be improved. .

FIG. 77 is a view similar to FIG.
And an example in which the phase compensation medium 100 is attached to a polarizing plate on the TN liquid crystal display element 2 side.

The above-described high resolution technology can be used regardless of the mode, such as a direct view type as shown in FIG. 69 and a projection type as shown in FIGS. 78 to 82. Here, FIGS. 78 to 82 correspond to FIGS.
Corresponding to FIG. 47, the phase compensation medium
The difference is that 100 is provided, but the operating principle is basically the same.

Application to Imaging Device This phase compensation effect can be applied to the application to the imager described above. The FLC element used here was one in which the electrodes were not divided. This is because there is no need to perform a temporal shift since the imaging is performed at the same time. In addition, when a polycarbonate film is used as the phase compensation medium, the optical axis shift can be reliably performed in a wide wavelength range, and the effect of increasing the resolution is improved.

FIGS. 83 to 88 show specific implementation examples 171 respectively. In each case, high resolution was obtained by effective pixel shifting. Also, Sony's Handycam T
An example of implementation on R1 is also shown in FIG. These drawings respectively correspond to FIGS. 53 to 59 described above, and differ in that a phase compensation medium 100 is provided at a predetermined position, but the operation principle is basically the same. .

In the imager of the above example, the birefringence anisotropy Δn = n _e −n of the low-pass filter using the quartz plate
By using _o = 0.0091, moire fringes and false color signals of the CCD image sensor are removed. However, when the light incident on the low-pass filter is linearly polarized light, the effect of the low-pass filter is reduced.

Therefore, as shown in FIG. 89, a 波長 wavelength plate 130 is provided between the optical axis shifting birefringent medium 4 and the low-pass filter.
Place. This is because the quarter-wave plate places the slow axis at an angle of approximately 45 degrees for each polarized light from the birefringent medium.
This is because the effect of the low-pass filter functions sufficiently because the linearly polarized light becomes the circularly polarized light.

For example, in the case of FIG. 89 (A), the polarized light 12 parallel to the Y-axis that has exited the birefringent medium 4 for shifting the optical axis passes through the quarter-wave plate 130 and is directed in the direction of the slow axis. Then, the light becomes the left-handed circularly polarized light and enters the quartz low-pass filter. Meanwhile, the figure
In the case of 89 (B), the polarized light 12 parallel to the X axis exiting the birefringent medium for shifting the optical axis is converted into right circularly polarized light that rotates in the direction of the slow axis when passing through the quarter-wave plate 130. And enters the quartz low-pass filter. As a result, since the crystal low-pass filter is not affected by polarization, the optical low-pass filter effect can be effectively performed. As a result, an image with high resolution and reduced moiré fringes and false color signals can be captured. .

Although the embodiments of the present invention have been described above, the above embodiments can be further modified based on the technical idea of the present invention.

For example, the structure, material, shape, assembling method, and the like of each component, including the above-described liquid crystal element, may be variously changed. The substrate is not limited to a glass plate, but may be any other optically transparent material. Various liquid crystals can also be adopted.

The object to which the present invention is applied, of course, includes not only the optical system such as the above-described display device and imaging device, but also a wobbling element that can be incorporated in the system.

[0286]

As described above, the present invention provides at least one type of liquid crystal selected from ferroelectric liquid crystal (FLC), antiferroelectric liquid crystal (AFLC), and smectic liquid crystal (SmA) exhibiting an electroclinic effect. Is a combination of a phase modulation optical element injected into the gap between the substrates and an optically transparent birefringent medium, so that the phase of the light is changed by the phase modulation optical element. Since the polarization plane is shifted and the incident light is selectively refracted by the above-mentioned birefringent medium, it is possible to effectively wobble the discrete pixels, improve the resolution, and improve the image quality. it can.

The liquid crystal such as ferroelectric liquid crystal used in the above-mentioned phase modulation optical element easily changes the direction of the liquid crystal director in response to the action of an electric field, and has a very fast response speed. Can be driven sufficiently. In addition, since a phase adjusting medium for rotating the polarization plane by about 90 degrees in a wide wavelength range to shift the optical axis is further disposed at the rear and / or front of the phase modulation optical element, high resolution can be achieved. , The wavelength range of light that rotates the polarization plane by about 90 degrees can be widened, high contrast, high resolution can be improved, color unevenness can be suppressed, and integration over the used wavelength range between fields during wobbling. The amount of crosstalk can be reduced compared to a wobbling element without phase adjustment. Further, since the wavelength range in which the wobbling effect can be obtained can be extended to the entire visible light region, the height of a display element or an imaging element composed of three plates of red (R), green (G), and blue (B) is particularly high. The resolution can be increased by one wobbling element, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view of a display device in a state 1 according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of the display device in a state 2;

FIG. 3 is an explanatory diagram of a cone angle of a ferroelectric liquid crystal (FLC) used in the display device.

FIG. 4 is a graph showing the temperature dependence of the cone angle.

FIG. 5 is a graph showing the temperature dependence of the same cone angle in another liquid crystal.

FIG. 6 is a schematic diagram similar to FIG. 2 for explaining a shift of an abnormal optical axis of an FLC of the display device.

FIG. 7 is a diagram for explaining crosstalk between fields during wobbling (picture element shifting).

FIG. 8 is a schematic diagram of a system for measuring the degree of polarization during wobbling.

FIG. 9 is a graph showing a transmission spectrum change of a liquid crystal.

FIG. 10 is a graph similar to FIG. 9.

FIG. 11 is a graph showing a change in transmittance.

FIG. 12 is a diagram for explaining a preferable cone angle of the liquid crystal.

FIG. 13 is an explanatory diagram of an improved liquid crystal director direction.

FIG. 14 is a schematic diagram similar to FIG. 2 in a state 2 of the liquid crystal director.

FIG. 15 is a schematic diagram similar to FIG. 1 in a state 1 of the liquid crystal director.

FIG. 16 is a transmission spectrum diagram of an RGB filter used in the display device.

FIG. 17 is a schematic diagram of a specific example of the display device in each switch state.

FIG. 18 is a schematic diagram of a case where a normally white TN liquid crystal display element is used in the display device.

FIG. 19 is a schematic diagram in the case where a normally black TN liquid crystal display element is used in the display device.

FIG. 20 is a schematic diagram of a display device using a display element with a small degree of polarization.

FIG. 21 is a cross-sectional view of a liquid crystal cell as a phase modulation element using an FLC liquid crystal element.

FIG. 22 is a graph showing a change in a phase difference due to a cell gap of the liquid crystal cell.

FIG. 23 is a waveform chart showing various driving methods of the phase modulation element.

FIG. 24 is an explanatory diagram of an optical axis shift due to a birefringent medium.

FIG. 25 is a schematic perspective view of a wedge cell serving as a birefringent medium.

FIG. 26 is a schematic diagram illustrating optical properties of the wedge cell.

FIG. 27 is a schematic diagram illustrating optical properties of another wedge-type cell.

28A and 28B are a plan view and a perspective view showing a molding die of still another birefringent medium and the same medium.

FIG. 29 is a schematic diagram showing a shift amount at the time of wobbling (picture element shifting) in each case.

FIG. 30 is an explanatory diagram of a wobbling state.

FIG. 31 is an explanatory diagram of another wobbling state.

FIG. 32 is an explanatory diagram of still another wobbling state.

FIG. 33 is an explanatory diagram of a wobbling state of the RGB inline array display element.

FIG. 34 is an explanatory diagram of a wobbling state of the RGB delta array display element.

FIG. 35 is a schematic perspective view showing divided electrodes in the phase modulation element.

FIG. 36 is an explanatory diagram of an interlaced scanning method.

[Fig. 37] Fig. 37 is a waveform diagram of a synchronization signal in each field of the television.

FIG. 38 is a block diagram showing a connection relationship between elements of the display device.

FIG. 39 is a drive waveform diagram of the electrode-divided phase modulation element.

FIG. 40 is a schematic diagram of a display device using the same element.

FIG. 41 is a schematic view of another display device using the same element.

FIG. 42 is a cross-sectional view of a structural example of the display device.

FIG. 43 is a cross-sectional view of another example of the structure.

44 is a sectional view of still another example of the structure. FIG.

FIG. 45 is a cross-sectional view of a display to which the display device is applied.

FIG. 46 is a cross-sectional view of another application example to a display.

FIG. 47 is a cross-sectional view of still another application example to a display.

[Fig. 48] Fig. 48 is a schematic diagram of an imaging device in a state 1 according to another embodiment of the present invention.

FIG. 49 is a schematic diagram of the imaging device in a state 2;

FIG. 50 is a schematic diagram similar to FIG. 49 for explaining a shift of an abnormal optical axis of an FLC of the imaging device.

FIG. 51 is an improved liquid crystal director in state 2
FIG. 49 is a schematic view similar to 49.

FIG. 52 is a schematic diagram similar to FIG. 48 in a state 1 of the liquid crystal director.

[Fig. 53] Fig. 53 is a schematic diagram of a specific example of the imaging device.

[Fig. 54] Fig. 54 is a cross-sectional view of a structural example of the imaging device.

FIG. 55 is a schematic view of a mounted state of a quartz optical low-pass filter.

FIG. 56 is a principle diagram for explaining blur caused by three pieces of the quartz filters.

FIG. 57 is a cross-sectional view of a mounting example of the imaging device.

FIG. 58 is a cross-sectional view of another mounting example.

FIG. 59 is a cross-sectional view of still another mounting example.

FIG. 60 is a schematic view of a specific example of a display device according to another embodiment of the present invention in each switch state.

FIG. 61 is an explanatory diagram showing a relationship between an optical axis in each state of an FLC element and a phase compensation (phase adjustment) film in the display device.

FIG. 62 is an explanatory diagram showing an optical arrangement in a case where there is no phase compensation in the display device.

FIG. 63 is a transmittance spectrum diagram in each state in the optical arrangement.

FIG. 64 is an explanatory diagram illustrating an optical arrangement when phase compensation is performed in a display device.

FIG. 65 is a transmittance spectrum diagram in each state in the optical arrangement.

FIG. 66 is a schematic view of a specific example of a display device according to another embodiment of the present invention in each switch state.

FIG. 67 is a schematic plan view of a substrate illustrating various alignment processing directions in the display device.

FIG. 68 is a schematic plan view for explaining a state at the time of assembling the liquid crystal cell in the display device.

[Fig. 69] Fig. 69 is a schematic diagram illustrating a method for increasing the resolution in the vertical and / or horizontal directions.

FIG. 70 is a driving waveform chart for explaining a liquid crystal element driving method.

FIG. 71 is a cross-sectional view of a structural example of the display device.

FIG. 72 is a cross-sectional view of another example of the structure.

FIG. 73 is a cross-sectional view of another example of the structure.

FIG. 74 is a cross-sectional view of another example of the structure of the display device.

FIG. 75 is a cross-sectional view of another example of the structure of the display device.

FIG. 76 is a cross-sectional view of another example of the structure of the display device.

FIG. 77 is a cross-sectional view of still another example of the structure of the display device.

FIG. 78 is a cross-sectional view of a display to which the display device is applied.

FIG. 79 is a cross-sectional view of another application example to a display.

FIG. 80 is a cross-sectional view of another application example to a display.

FIG. 81 is a cross-sectional view of another application example to a display.

FIG. 82 is a cross-sectional view of still another application example to a display.

[Fig. 83] Fig. 83 is a schematic diagram of a specific example of an imaging device according to another embodiment of the present invention.

84 is a sectional view of a structural example of the imaging device. FIG.

FIG. 85 is a cross-sectional view of another example of the structure of the imaging device.

86 is a cross-sectional view of still another example of the structure of the imaging device. FIG.

FIG 87 is a cross-sectional view of a mounting example of the imaging device.

FIG. 88 is a cross-sectional view of another mounting example.

FIG. 89 is a schematic diagram of a specific example of an imaging device according to still another embodiment of the present invention.

[Explanation of symbols]

 1, 101 ... (liquid crystal optical) display device 2 ... (liquid crystal) display element 3 ... ferroelectric liquid crystal element 4 ... birefringent medium 5 ... display pixel 7, 107 ... wobbling Element (picture element shifting element) 8, 10: extraordinary optical axis 9: polarization direction 13, 14, transparent electrode 15: liquid crystal 17: light source 18, 19: polarizing plate 20, 21: transparent substrate 22, 23: alignment film 50: subject 53: CCD element 61: infrared cut filter 64: optical low-pass filter 71, 171: imaging device 100, 110: phase compensation (phase adjustment) medium 108, 118: slow axis

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Eriko Matsui 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Within Sony Corporation (72) Inventor Eibo Yang 7-35, Kita-Shinagawa, Shinagawa-ku, Tokyo No. 72 within Sony Corporation (72) Inventor Hidefumi, 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Examiner within Sony Corporation Masashi Migita (56) References JP-A-4-63074 (JP, A) JP-A-5-289044 (JP, A) JP-A-4-113308 (JP, A) JP-A-2-271326 (JP, A) JP-A-5-Japanese 88144 (JP, A) JP-A-2-87122 (JP, A) JP-A-4-152322 (JP, A) JP-A-4-177216 (JP, A) JP-A-60-83486 (JP, A) JP-A-61-251819 (JP, A) JP-A-63-53519 (JP, A) Open Akira 61-252532 (JP, A) JP Akira 62-191824 (JP, A) (58 ) investigated the field (Int.Cl. ^7, DB name) G02F 1/13 505 G02F 1/1335 G02F 1/137 G02F 1/133

Claims (37)

(57) [Claims] 1. A plurality of optically transparent substrates provided with an optically transparent electrode and an alignment film in this order are arranged facing each other with a predetermined gap therebetween on the electrode and the alignment film side, A phase modulation optical element in which at least one type of liquid crystal selected from a ferroelectric liquid crystal, an antiferroelectric liquid crystal, and a smectic liquid crystal exhibiting an electroclinic effect is injected into the gap; An optically transparent birefringent medium disposed at a position for receiving the polarized light to selectively shift the optical axis of the light according to the polarization direction of the light; And a phase adjustment medium for shifting the optical axis by rotating the polarization plane by about 90 degrees in a wide wavelength range; and the phase modulation optical element, the birefringent medium, and the phase adjustment medium. But observation position and high resolution Between the display element to be,
Alternatively, an optical device which is arranged in an optical path between a subject and an image sensor to form a wobbling element, and wherein the display element or the image sensor is wobbled one-dimensionally or two-dimensionally. 2. The birefringent medium is composed of a transparent substrate that shifts the optical axis depending on the polarization direction of incident light, and is arranged so as to have a component of an extraordinary optical axis that is equivalent to a wobbling direction. 2. The optical device according to claim 1, wherein the substrate facing surface through which light passes is not parallel, and an apparent abnormal optical axis is parallel or perpendicular to a plane perpendicular to both facing surfaces. 3. The optical device according to claim 1, wherein the wobbling element is driven at a video rate. 4. A phase adjusting medium comprising one of an element composed of a liquid crystal material containing a π-electron system, an active liquid crystal element having a liquid crystal sandwiched at least between transparent electrodes, and a polymer film containing a π-electron system. The optical device according to claim 1, wherein the crosstalk as an integral amount in a used wavelength range between fields during wobbling is reduced as compared with a wobbling element in which phase adjustment is not performed. 5. The phase of the liquid crystal after the phase compensation in the two switch states, the slow axis of the birefringence having a large absolute value, the polarization plane (P1) of the light from the display element, or the polarization orthogonal thereto. 2. The optical device according to claim 1, wherein an angle δ between a bisector of the plane (P2) and the plane of polarization (P1) or (P2) is 22.5 ± 10 degrees. 3. 6. A phase adjusting medium comprising an optically transparent and uniformly oriented smectic liquid crystal (including chiral liquid crystal) element, a nematic liquid crystal element, a main chain type polymer liquid crystal, and a side chain type polymer. Liquid crystal, aromatic polyester film,
Polycarbonate film, polystyrene or styrene resin film, methacrylic resin film, vinyl resin film, cellulose film, polyamide resin film, polyphenylene film, polyphenylene sulfide film, polysulfone film And an amorphous polyarate film, a polyethersulfone-based film, a polyetherimide-based film, a polyetherketone-based film, a polyamideimide-based film, and a polyimide-based film. The optical device according to claim 4. 7. The optical device according to claim 6, wherein the phase adjusting film constituting the wobbling element for the display element is not directly attached to the phase modulation optical element made of a chiral smectic liquid crystal. 8. The optical device according to claim 6, wherein the phase adjusting film and the polarizing plate constituting the wobbling element for the imaging element are not directly attached to the phase modulation optical element made of a chiral smectic liquid crystal. 9. Rotating the plane of polarization about 90 degrees over a wide wavelength range to minimize wobbling crosstalk,
The phase difference of the phase modulation optical element made of chiral smectic liquid crystal and the phase difference of the phase adjusting medium, and further the axis of the incident polarized light,
The optical device according to claim 1, wherein a direction of a slow axis of the phase modulation optical element, a direction of a slow axis of the phase adjustment medium, and a direction of an extraordinary optical axis of a birefringent medium for shifting an optical axis are adjusted. 10. The optical device according to claim 9, wherein the alignment processing direction of the phase modulation optical element made of a chiral smectic liquid crystal is parallel or perpendicular to the pixel shifting direction. 11. The optical device according to claim 10, wherein the alignment treatment is performed by rubbing or vacuum deposition. 12. The optical device according to claim 9, wherein a phase difference at 632.8 nm of the phase modulation optical element comprising a chiral smectic liquid crystal is 160 nm to 380 nm. 13. The optical device according to claim 12, wherein the phase adjusting medium exhibits a retardation of 160 nm to 380 nm and has the same phase difference as that of a phase modulation optical element made of chiral smectic liquid crystal at 632.8 nm. 14. The slow axis of the phase adjusting medium is substantially orthogonal to the slow axis of one of the two switching states of the liquid crystal director of the phase modulation optical element.
The optical device according to claim 1. 15. The optical device according to claim 1, wherein the display element or the imaging element to be improved in resolution is a liquid crystal display element composed of discrete pixels, a self-luminous display element, or a charge-coupled element. 16. When a light from a display element or a subject to be improved in resolution is not polarized, an element for providing polarization is disposed in an optical path between the wobbling element and the display element or the subject. The optical device according to claim 1. 17. The liquid crystal used is a bookshelf,
The optical device according to claim 1, wherein the optical device is a chiral smectic liquid crystal having a pseudo bookshelf or a liquid crystal layer structure having a chevron structure. 18. The optical device according to claim 17, wherein the pretilt angle of the chiral smectic liquid crystal is 0 to 45 degrees. 19. The apparent cone angle θ of the liquid crystal used
The optical device according to claim 1, wherein is between 26 and 64 degrees. 20. The bisector between each director in the two switch states of the liquid crystal used for the phase modulation optical element, the plane of polarization (P1) of the light from the display element or the plane of polarization (P2) orthogonal thereto. The angle δ is 22.5 ± 10 degrees when the phase adjustment (or compensation) is not performed; or in the two switch states of the liquid crystal in the phase modulation optical element that has performed the phase adjustment (or compensation). Among the switch states after the phase compensation, the bisector between the slow axis of the birefringence having a large absolute value and the polarization plane (P1) or (P2) is the polarization plane (P1) or ( P2) and the angle δ1
The optical device according to claim 1, wherein δ1 = 22.5 ± 10 degrees. 21. When a liquid crystal display or an image sensor as a display device to be improved in resolution is a single plate having red, green and blue trio images as one picture element, measurement is performed using a light source of 632.8 nm. The optical device according to claim 1, wherein the determined phase difference is in a range of 130 nm to 370 nm. 22. When the liquid crystal display or the image sensor as a display device to be improved in resolution has three plates, the upper limit of the wavelength range of the transmittance characteristic of each filter to be combined is λ
Let _Max be the lower limit and λ _Min be the allowable phase difference is λ
_Max / 2 to λ _Min / 2, with red, green,
When the emission of the blue phosphor is used, each effective phase difference range is (λ _C -100) when the center wavelength is λ _C.
2. The optical device according to claim 1, wherein the ratio is in the range of (1/2) to (λ _C +100) / 2 (where the unit of each phase difference is nm). 23. The imaging wavelength includes infrared light (wavelength 700 to 1).
200nm), the phase difference measured using a 632.8nm light source
The optical device according to claim 1, wherein the optical device has a range of 350 nm to 600 nm. 24. The optical device according to claim 1, wherein the phase modulation optical element is driven using a bipolar applied voltage. 25. At the time of wobbling, each response time of the rise and fall of the drive voltage is 1/100 of the field time.
The optical device according to claim 1, wherein the ratio between the rise time and the fall time is not more than twice each other. Respect 26. wobbling direction of length component picture element diameter (monochrome screen or 3 pixel apertures when the plate is a single plate red, green, and one pixel trio blue.) The L _A , when the pixel pitch and L _P, the pixel shift amount _{L, Min (L P -L a,} L a / 2) ≦ L ≦ Max (L a, L P -L a / 2) ( where, 2. The optical device according to claim 1, wherein Min (x, y) and Max (x, y) are functions giving a small value and a large value of x and y, respectively. 27. The display device according to claim 1, wherein a display element having the number N of horizontal scanning lines and a phase modulation optical element having drive electrodes divided into N to 1 in the screen vertical direction of the display element are combined. Optical device. 28. The optical device according to claim 27, wherein a distance between the divided electrodes is longer than a liquid crystal cell gap. 29. The driving of the display element and the driving of the phase modulation optical element are synchronized based on the detected video vertical synchronizing signal, the time of one field is divided by the required number of electrodes, and each channel of the phase modulation optical element is divided. 28. The optical device according to claim 27, wherein the optical device is sequentially driven with a time delay in a field. 30. The method according to claim 30, wherein the drive of the image pickup device and the drive of the phase modulation optical device are synchronized with each other on the basis of the synchronization signal, an image is taken in each field, and data is transferred to form one frame. 2. The optical device according to 1. 31. The optical device according to claim 1, wherein the birefringent medium for shifting the optical axis and the phase modulation optical element are bonded with an optical adhesive. 32. The optical device according to claim 1, wherein a transparent electrode and an alignment film are provided on a quartz plate serving as a birefringent medium and integrated with a liquid crystal element. 33. The optical device according to claim 1, wherein the optical device is configured as a direct-view, reflective or projection display device. 34. The optical device according to claim 1, wherein the optical device is used in a visible light wavelength range. 35. The optical device according to claim 1, wherein the wobbling element is combined with a solid-state image sensor to constitute a visible light or infrared light image pickup device. 36. The optical device according to claim 35, wherein the wobbling element, the optical low-pass filter, and the solid-state imaging device are combined. 37. A quarter wave plate is disposed in an optical path between the wobbling element and the optical low-pass filter;
An optical device according to claim 36.