JP3285169B2 - 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 imaging pixels constituting the CCD are discrete, the image information of the subject is sampled at the 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. Further, the conventional device has a limit in spatial resolution.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wobbling (picture element shift) which can easily cope with a video rate at a high speed with respect to a display comprising discrete pixels, a solid-state image pickup device comprising discrete light receiving pixels, and the like. It is an object of the present invention to provide an optical device capable of efficiently achieving high resolution and improving a mosaic-like point-drawing screen or the like into a continuous screen without any seams.

[0009]

That is, the present invention relates to a method of controlling a phase modulation optical element between a display element to be improved in resolution and an observation position or an optical path between a subject and an image pickup element. An optical device in which a combination of wobbling elements in which transparent birefringent media are sequentially arranged is arranged, and the display element or the imaging element is wobbled one-dimensionally or two-dimensionally. As a modulation optical element, 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 side of the electrode and the alignment film, At least one type of liquid crystal (may be a mixed liquid crystal) selected from ferroelectric liquid crystal (FLC), antiferroelectric liquid crystal (AFLC), and smectic liquid crystal (SmA) exhibiting an electroclinic effect. Injected into The number of horizontal scanning lines of the display element is N, and the electrodes on at least one of the plurality of substrates are divided in the scanning direction by an integral division of N / 2 or (N + 1) / 2 or less. The present invention relates to an optical device characterized in that a phase modulation optical element is used.

According to the optical device of the present invention, in one wobbling element, the phase of light is changed by the phase modulation optical element to shift the plane of polarization, and the incident light is selectively refracted by the birefringent medium. And the above operation can be further performed in another combined wobbling element, and furthermore, N / 2 or (N + 1) / 2 in the scanning direction.
Driving by the above-mentioned divided electrodes can be effectively performed in the corresponding area, so that not only one-dimensional but also two-dimensional wobbling can be effectively performed on discrete pixels, and the resolution can be further improved (vertical and horizontal). Resolution in both directions). Further, the mosaic-like point drawing screen can be improved to a continuous screen without any seams, and the image quality can be improved.

[0011] In any of the liquid crystals such as ferroelectric liquid crystal used in the above-mentioned phase modulation optical element, the direction of the liquid crystal director is easily changed by the action of an electric field, and the response speed is extremely fast (for example, rising and falling). Both fall time μ
(Second order to several msec, which is much faster than the falling time of the twisted nematic liquid crystal), so that driving at a video rate is sufficiently possible.

[0012]

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. May be. In this case, it is preferable that the extraordinary optical axis forms an angle of 10 to 80 degrees with respect to the wobbling optical system.

Further, a liquid crystal display element such as a twisted nematic liquid crystal, a ferroelectric liquid crystal or an anti-ferroelectric liquid crystal, in which a display element or an image pickup element to be improved in resolution is composed of discrete pixels, and 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, an element for giving polarization is arranged in the optical path between the combination of the wobbling elements and the display element or the object. Is good.

In the present invention, high resolution can be achieved by combining n (n is an integer) wobbling elements and shifting the optical axis of the birefringent medium over 2 ⁿ points. In this case, the spatial resolution can be further improved by a combination of birefringent media having different thicknesses.

A phase modulation element (for example, a chiral smectic liquid crystal element) for rotating the polarization plane by 90 ° ± 45 ° is arranged in an optical path between the combination of the wobbling elements and the observation position or the imaging element. When the modulation element is configured to be synchronized with the change in the polarization direction at the time of wobbling so as to align the polarization plane at the time of wobbling, when a polarizing screen or the like is arranged on the light emission side of the wobbling element combination, This is advantageous when the reflectivity is dependent on the degree of polarization.

Further, when driving each phase modulation optical element in the combination of wobbling elements, if the driving cycle is at least four times the wobbling cycle, the driving cycle can be lengthened to correspond to the driving at the video rate. It will be easier.

In this case, when driving each phase modulation optical element of the two combined wobbling elements, the driving cycle of each of these phase modulation optical elements is set to four times the wobbling cycle, and the phase of the driving cycle is set to four times. When the liquid crystal elements are shifted from each other by 90 degrees, the number of switching times of the liquid crystal element can be reduced, and the condition of the driving speed can be relaxed.

In the present invention, the above-mentioned "optical device" means, of course, only a combination of the above-mentioned wobbling elements, but also includes a display device, an image pickup device and the like provided with this combination. I do.

[0021]

Embodiments of the present invention will be described below.

[1] One-Dimensional Two-Point Pixel Shift First, a one-dimensional two-point pixel shift will be described with reference to FIG.

In the case of wobbling of the display element, the polarized light 6 from the liquid crystal display element (not shown) is applied to the liquid crystal phase modulation element 3 (modulation element A) composed of a chiral smectic liquid crystal optical element.
), And the polarization plane is not changed (this is referred to as “switch state 1”), the polarization plane is refracted because it is parallel to the extraordinary optical axis 10 of the birefringent medium 4. The optical axis shifts upward, and this emitted light 12 is perceived by the eye directly as a picture element at position a, or directly after passing through a lens system or after being received by a reflection system such as a screen, and then perceived by the eye.

Next, the polarization plane is substantially changed by the liquid crystal phase modulation element 3.
When rotated 90 degrees (this is referred to as “switch state 2”), the polarization plane does not refract because it is perpendicular to the extraordinary optical axis of the birefringent medium 4, and the optical axis does not shift, and A picture element is perceived.

According to the wobbling element 7, an optical shift occurs between the two states described above, and since this operation is performed within one frame, the resolution is intuitively increased.

In the case of wobbling of the image pickup device: Since the light from the subject (not shown) does not contain much polarized light components, it is necessary to insert a polarizing plate between the subject and the phase modulation device 3. With this configuration, the light from the subject is polarized in one direction, and then is incident on the liquid crystal phase modulation device 3 composed of a chiral smectic liquid crystal optical element. The refraction medium is refracted to be parallel to the extraordinary optical axis, and the optical axis shifts upward,
The light enters the image sensor.

Next, the plane of polarization is substantially changed by the liquid crystal phase modulation element 3.
In the “switch state 2” rotated by 90 degrees, the polarization plane is perpendicular to the extraordinary optical axis 10 of the birefringent medium 4 so that it is not refracted and enters the image sensor without shifting the optical axis.

An optical shift occurs between these two states, and light from different places of the subject can be captured by the same image-capturing picture element. Is formed, the spatial resolution of imaging is improved in the pixel shifting direction.

[2] Two-dimensional four-point picture element shift As shown in FIG. 1, a one-dimensional two-point picture element having phase modulation elements A and B composed of chiral smectic liquid crystal optical elements 3-1 and 3-2, respectively. Two sets of shift elements (7-1 and 7)
-2) Prepare (4-1 and 4-2 in the figure are birefringent media, 10
-1 and 10-2 are abnormal optical axes), and one element A is combined with another element B by rotating the element B by 90 degrees around the incident optical axis, and the two elements are stacked. , The resolution in the vertical and horizontal directions is increased. Here, the one that does not substantially change the polarization plane of the incident light is referred to as “switch state 1”, and the one that rotates about 90 degrees is “switch state 2”.

FIG. 2 shows the relationship between the switch state and the picture element shift position. It can be seen that the resolution is improved in the vertical and horizontal directions due to the shift in the picture element position.

In such wobbling, since four pixel shifts are performed within one frame or one field, all operations must be completed within 1/30 seconds or 1/60 seconds. Therefore, 1/120 second (about 8.3ms)
Switching must be completed within 20% of the time of 1/240 second (about 4.2 ms). That is, rising,
It is necessary for the fall response speed to be about 0.8 to 1.6 ms or less, but in order to practically satisfy this condition between -10 ° C and 70 ° C, a chiral smectic liquid crystal device exhibiting high-speed response is required. It becomes feasible only by using.

However, in the switching pattern shown in FIG. 2, as shown in the waveform diagram of FIG. 3, the switching state of the modulation element A must be switched four times in one cycle.

Therefore, by changing the switching pattern as shown in FIGS. 4 and 5, the driving of the modulation element A can be performed only by switching twice in one cycle. A shift can be achieved. In other words, in the driving of the element composed of the two sets of wobbling elements, the driving cycle of the two elements is four times the picture element shifting cycle and the driving cycle is shifted by 90 degrees from each other. The driving speed specifications can be reduced.
In this case, since the driving cycle can be lengthened, it is easier to handle the video rate.

[3] When projecting on a polarizing screen or the like The polarization plane of the light during the wobbling operation is as described in the above [1],
As described in [2], simply wobbling element 7-1
By simply combining and, light whose polarization plane is switched by about 90 degrees is mixed. When the polarizing screen 70 is used as shown in FIG. 7 for high brightness, if the polarization directions are not aligned, sufficient high resolution characteristics cannot be obtained.

However, in the optical path connecting the wobbling element and the observer, a phase modulation element 73 (here, a chiral smectic liquid crystal element X) capable of rotating the polarization plane by about 90 degrees.
, The polarization plane at the time of wobbling can be made uniform.

FIG. 8 shows an example in which such a phase modulation element 73 is applied to two-dimensional four-point wobbling. Thus, as shown in FIG. 9, the polarization plane of the light emitted from the wobbling element can be aligned in one direction (that is, in the vertical or horizontal direction) by switching of the phase modulation element 73. By arranging the polarization planes in this way, it is possible to improve the reflectance in the case where the reflectance depends on the degree of polarization as in a polarizing screen, and to achieve high resolution by wobbling even through a polarizing screen.

[4] One-dimensional picture element shift for one frame of 2 ⁿ fields FIG. 10 shows a plurality of wobbling elements 7-1, 7-2,... 7 combining a liquid crystal phase modulation element and a birefringent medium. −
3 shows a wobbling element formed by stacking n and n sheets.
In this case, in principle, as deviation of the optical axis to provide a birefringent medium is L, L / 2, L / 4, the · · · L / 2 ^n,
Laminate wobbling elements. Specifically, the crystal plate 4-
The thickness of 1, 4-2... 4-n is d / 2 ^n, and d, d
.., D / 4... D / 2 ⁿ . Furthermore, by driving the liquid crystal phase modulation elements by aligning the direction of the extraordinary optical axis of the birefringent medium during this lamination,
It is possible to perform picture element shifting with a spatial resolution of 2 ⁿ points over a distance of length L (2-1 / 2 ⁿ ).

More specifically, when n = 3, a one-dimensional picture element shifting element for eight fields and one frame can be realized as shown in FIG. That is, assuming that the deviation of the optical axis provided by the quartz plate having the thickness d is L, it is possible to increase the resolution by shifting the picture element by dividing the distance of 1.875 L into eight points. Thus, the spatial resolution can be further improved by laminating birefringent media having different thicknesses.

[5] Two-dimensional picture element shift for one frame of 2 ⁿ × 2 ⁿ fields This picture element shift is described in [1] to [2] above.
The method of extension to [4] may be applied to [4] described above. This enables 2 ⁿ × 2 ⁿ point two-dimensional picture element shifting.

Specifically, 4 × 4 picture elements can be shifted by laminating four sets (where n = 2) of wobbling elements using quartz substrates having different thicknesses as shown in FIG. High resolution can be achieved. Further, FIG. 13 shows that the effect of increasing the resolution does not depend on the stacking order of the birefringent media having different amounts of shift of the transmitted light.

Next, the wobbling operation described above will be described in more detail. FIGS. 14 and 15 show the structure shown in FIG.
One wobbling element 7 will be described, but this can be understood as the principle of operation of the elements shown in FIGS. 1, 7, 8 and 10 to 13 (the same applies hereinafter).

Here, the case where the wobbling element is applied to the liquid crystal optical display device 1 will be described. However, the liquid crystal display element (LC) which is sequentially arranged in the same optical path along the traveling direction of light is described.
D) 2, a ferroelectric liquid crystal element (FLC) 3 as a phase modulation optical element, and a birefringent medium 4 made of a transparent substrate such as a quartz plate. here,
For easy understanding, each component is a liquid crystal display element LCD.
Are shown for each of the sections corresponding to one of the constituent display pixels 5 (the same applies hereinafter).

The pixel 5 of the LCD 2 has a discrete pixel arrangement such as a mosaic as a whole, and the liquid crystal used is TN (twisted nematic) or STN.
(Super twisted nematic), SH (super homeotropic), and FLC. This LCD
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 this 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 this shift of the optical axis is used as an operation principle of the picture element shifting. it can.

Here, FLC3 (elements 3-1 to 3-3 described above)
The same applies to −n; the same applies to the following description). 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 the southern-Goldstone mode described in P150 of “Liquid Crystal Dictionary” (published by Baifukan). Move on a virtual cone. Further, in the smectic A liquid crystal having the electroclinical effect (P145 of the same liquid crystal dictionary), P11 of the same liquid crystal dictionary is used.
Even if you use the soft mode described in 9
Each liquid crystal composition has a cone angle similar to the cone angle.

That is, consider a cone model of a liquid crystal 15 sandwiched between transparent electrodes 13 and 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.

Next, FIG. 17 shows a switch state of a specific combination example of each element constituting the liquid crystal optical device. 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, T
An example of a combination with an N liquid crystal will be described.

In the case of a normally white TN liquid crystal display element shown in FIG. 18, light from a light source is transmitted in a state where 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 in a state where an electric field is applied to the TN liquid crystal. As the electric field intensity decreases, the twist of the TN liquid crystal 2 gradually increases. 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.

Thus, 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 in 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, wobbling using a phase modulation element (ferroelectric liquid crystal, antiferroelectric liquid crystal, or smectic A liquid crystal having an electroclinic effect) 3 including a chiral smectic liquid crystal which can be driven at a video rate. The element 7 is composed of liquid crystal, plasma, L
The wobbling (picture element shifting) can be performed by placing the display such as an ED in the optical path connecting the retina of the observer. Here, the phase modulation element 3 will be described in detail.

The usable element 3 includes the following [1]
Or [2]. [1] At least two states exist in a 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. Is 26-64
A chiral smectic liquid crystal element with an angle of degree and optically arranged so that the plane of polarization can be rotated.

[2] A transparent birefringent medium is a transparent substrate that shifts the optical axis depending on the polarization direction of the incident light. Specifically, the component of the extraordinary optical axis is uniaxially equivalent to the wobbling direction. An element arranged to have

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

The structure of the ferroelectric liquid crystal switching element 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 facing 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 Chemical Industry) 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) 15 was injected under reduced pressure in a state showing 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 in the present invention can be manufactured by Chisso Co., Ltd., Merck Co., Ltd., manufactured by BDH, or a composition comprising, for example, the following ferroelectric liquid crystal compound or a non-chiral liquid crystal containing them. There is no such limitation, and no limitation on the phase series is required. What is required is that a chiral smectic liquid crystal phase be formed 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 in an X-ray structure, depending on the combination of the alignment treatment directions. Analysis clarified it.

[0069]

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[0070]

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[0071]

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[0072]

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[0073]

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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 an inclination 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 the 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.

High-speed response of FLC: rising (10-90
% T) and falling (90-10% T)
It shows a fast response in the order of sec, guarantees a sufficient response within one field, and achieves an effective picture shift effect at the video rate for the first time.

In particular, 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.

On the other hand, 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 1 below shows the response times of various liquid crystals in comparison. The response speed of the liquid crystal usable in the present invention is extremely high.

A birefringent transparent substrate that shifts the optical axis depending on the polarization direction of the incident light. Equivalently, the uniaxial extraordinary optical axis 10 exists on the same plane as the Z axis as shown in FIG. Elements 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. 22, 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.

[0086]

(Equation 1)

Here, the effective range of β for expressing the deviation L of the optical axis was 10 to 80 degrees. The deviation of the optical axis differs depending on the pixel pitch.

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 a 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 is set in synchronization with the vertical synchronizing signal in combination with the above-mentioned TFT color liquid crystal display element, the switching of the FLC element on the entire panel is 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 the experiment, it was found that high resolution was effective even in the vertical division of about 1/4.
That is, in order to increase the resolution, the electrode of the picture element shifting element combined with the display element having the number of horizontal scanning lines N is N
It is sufficient to divide the panel into one, but in order to increase the resolution of the entire panel, N to three divisions are preferable. Further, considering electrode processing accuracy, cost, etc., N / 2 or (N
An integer division of +1) / 2 or less is preferred.

Specific Example of Increasing Resolution of FLC Picture Shifting Element Using Five-Division Electrode Configuration: FIG. 23 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. 24, the scanning started from the point a reaches the point b in N / 2 horizontal scannings, moves to the point c in the vertical blanking period, and further N / 2 horizontal scannings. 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 of line sequential scanning such as the NTSC system, there is little problem in 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 for determining the timing of picture element shifting (wobbling) will be described. TV signal, Figure 25
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. 26 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.

In the above-mentioned five-division FLC element, the high resolution was examined in consideration of the driving conditions, the optical arrangement, and the amount of displacement of the picture elements. 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.

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

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,
27 to 29 show three examples of a projection display incorporating a wobbling element according to the present invention. However, for the sake of simplicity, the same reference numerals are given even if there are a plurality of elements 3 and 4.

In the example of FIG. 27, 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 wobbling process described above, the lens system
An image is projected from 44 to a screen 45.

FIG. 28 shows a mirror type display, and a light source.
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. 29 shows a prism type display,
28 is basically the same as that in FIG. 28 except that the light of each wavelength is synthesized via the dichroic prism 48.

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

The present invention is not limited to the display element 2 described above.
The present invention is also applicable to a case where the above-described wobbling element 7 is arranged in an optical path connecting an image pickup device such as a CCD composed of discrete pixels and a subject. This is the same for the elements 7-1 to 7-n according to the present invention.

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 sensor, for example, 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 object and the image sensor
In the optical path connecting 53, the subject, the polarizer, the FLC element, the birefringent substrate, and the imaging element are arranged 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. 30 and 31, when the switch state of the ferroelectric liquid crystal element 3 is state 1, the irradiation light component a from the subject 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 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.

The apparent cone angle deviates from 45 degrees due to the element environment temperature (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 is shifted from 90 degrees by an angle of γ, the component in the Y-axis direction also increases as the 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.

FIG. 32 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.

Unlike the display device, such an image pickup device is a light receiving device, 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, when the pixels of the CCD image pickup device are discrete and there is no displacement of the optical axis, 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.

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

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 (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. 33 and 34).

In this low-pass filter, incident light is made into a two-point blur by using 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 manner, 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. 35 shows an implementation example without such a low-pass filter, and FIG. 36 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. 37 shows a color separation camera system using three CCDs. However, CCD drive circuit,
The wobbling element drive circuit is omitted.

In the case of imaging of infrared light [0126] Using the near-infrared light region of a semiconductor image pickup device such as a CCD image pickup device, it is possible to pick up an image of only the near-infrared light region which cannot be sensed by human eyes. 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.

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, in FIG. 1, besides combining the two wobbling elements to be stacked by rotating them by 90 degrees around the optical axis, the rotation angles thereof can be variously changed. In some cases, both elements may be at the same angle to the optical axis. In addition, the two elements may not be combined in close contact with each other (that is, they may not be stacked), or may be opposed to each other with a certain gap. Further, the number of element combinations may be changed as appropriate.

In FIGS. 4 and 5, the polarity of the applied voltage in the state 1 and the state 2 of the element B can be reversed from that described above. Further, the rotation angle of the polarization plane by the phase modulation element 73 used in the example of FIG.
It may be a degree.

Although the above-described embodiments are all suitable for wobbling, for example, in the case of the example shown in FIG. 8, they can be applied to optical uses other than wobbling.

In addition, 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.

[0134]

According to the present invention, as described above, the phase modulation optical element is optically transparent between the display element to be improved in resolution and the observation position or in the optical path between the subject and the image pickup element. A birefringent medium and a combination of wobbling elements arranged sequentially, wherein the display element or the imaging element is wobbled one-dimensionally or two-dimensionally. As an element, a plurality of optically transparent substrates provided with an optically transparent electrode and an alignment film in this order are arranged opposite to each other with a predetermined gap therebetween on the side of the electrode and the alignment film. At least one type of liquid crystal selected from a crystalline liquid crystal, an antiferroelectric liquid crystal, and a smectic liquid crystal exhibiting an electroclinic effect is injected into the gap, and the electrode on at least one of the plurality of substrates is Assuming that the number of horizontal scanning lines of the display element is N, a phase modulation optical element divided in the scanning direction by an integer division of N / 2 or (N + 1) / 2 or less is used. The phase of the light is changed by the element to shift the plane of polarization, and the selective refraction of the incident light by the birefringent medium is two-dimensional (vertical,
Horizontal). Accordingly, wobbling can be performed effectively on discrete pixels, resolution can be improved, and image quality can be improved.

The liquid crystal such as a ferroelectric liquid crystal used in the 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 high response speed. Can be driven sufficiently. In addition, since a combination of a plurality of wobbling elements can be used, the driving cycle can be lengthened, and the video rate can be easily handled.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a wobbling element according to the present invention.

FIG. 2 is a table and a schematic diagram showing a switch state of the wobbling element, a picture element shift position, and a polarization direction after the shift.

FIG. 3 is a driving waveform diagram during wobbling by the wobbling element.

FIG. 4 is a table similar to FIG. 2 when the switch state of the wobbling element is changed.

FIG. 5 is a drive waveform diagram during the wobbling.

FIG. 6 is a principle diagram for explaining the wobbling operation.

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

FIG. 8 is a schematic perspective view of another wobbling element according to the present invention.

FIG. 9 is a table showing an operation of the wobbling element.

FIG. 10 is a schematic perspective view of another wobbling element according to the present invention.

FIG. 11 is a schematic perspective view and a side view of a specific example of the wobbling element.

FIG. 12 is a schematic perspective view of the wobbling element.

FIG. 13 is a schematic perspective view of still another wobbling element according to the present invention.

FIG. 14 is a schematic diagram of a display device to which the present invention can be applied in a state 1;

FIG. 15 is a schematic diagram of the display device in state 2;

FIG. 16 is an explanatory diagram of a cone angle of a ferroelectric liquid crystal (FLC) 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 an explanatory diagram of an optical axis shift due to a birefringent medium.

FIG. 23 is a schematic perspective view showing divided electrodes in the phase modulation element.

FIG. 24 is an explanatory diagram of an interlaced scanning method.

[Fig. 25] Fig. 25 is a waveform diagram of a synchronization signal in each field of the television.

FIG. 26 is a block diagram illustrating a connection relationship between elements of the display device.

FIG. 27 is a cross-sectional view of a display to which the display device is applied.

FIG. 28 is a cross-sectional view of another application example to a display.

FIG. 29 is a cross-sectional view of still another application example to a display.

[Fig. 30] Fig. 30 is a schematic diagram of an imaging device to which the present invention can be applied in state 1.

FIG. 31 is a schematic diagram of the imaging device in a state 2;

FIG. 32 is a schematic diagram of a specific example of the imaging device.

FIG. 33 is a schematic diagram of a mounted state of a quartz optical low-pass filter.

FIG. 34 is a principle diagram illustrating blur caused by three pieces of the same crystal filters.

FIG. 35 is a cross-sectional view of a mounting example of the imaging device.

FIG. 36 is a cross-sectional view of another mounting example.

FIG. 37 is a cross-sectional view of still another mounting example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... (Liquid crystal optical) display device 2 ... (Liquid crystal) display element 3,3-1-3-n ... Ferroelectric liquid crystal element 4,4-1-1-4-n ... Birefringence Medium 5 Display pixel 6 Polarized light 7, 7-1 to 7-n Wobbling element (picture element shifting element) 8, 10, 10-1, 10-2, 10-3 ... Extraordinary optical axis 9 ... Polarization direction 13,14 ... Transparent electrode 15 ... Liquid crystal 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 70 ... Polarizing screen 71 ... Imaging device 73 ... Phase modulation element d, d / 2 ... d / 2 ⁿ・ ・ ・ Thickness

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yang Eibo 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Hidehiko Takanashi 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Inventor Eriko Matsui 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Inventor Nobue Kataoka 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo (56) References JP-A-4-113308 (JP, A) JP-A-5-27255 (JP, A) JP-A-62-206522 (JP, A) JP-A-4-115786 (JP) (A) JP-A-2-52580 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1347 G02F 1/13 505 H04N 5/335 H04N 5/66 102

Claims (12)

(57) [Claims] 1. A phase modulation optical element and an optically transparent birefringent medium are sequentially arranged 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. An optical device in which a combined body of wobbling elements is arranged and the display element or the imaging element is wobbled one-dimensionally or two-dimensionally, wherein the phase modulation optical element is optically transparent. A plurality of optically transparent substrates provided with an electrode and an alignment film in this order are arranged facing each other with a predetermined gap therebetween on the side of the electrode and the alignment film, and a ferroelectric liquid crystal and an antiferroelectric liquid crystal are provided. And at least one liquid crystal selected from a smectic liquid crystal exhibiting an electroclinic effect is injected into the gap, and the electrodes on at least one of the plurality of bases reduce the number of horizontal scanning lines of the display element. And when the optical apparatus characterized by N / 2 or (N + 1) / 2 or less of the phase modulation optical element is divided in the scanning direction by an integer division is used. 2. When light from a display element or a subject to be improved in resolution is not polarized, an element for giving polarization is provided in an optical path between the combination of wobbling elements and the display element or the subject. The optical device according to claim 1, wherein the optical device is disposed. 3. The optical device according to claim 1, wherein the wobbling element is driven at a video rate. 4. The method according to claim 1, wherein n (n is an integer) wobbling elements are combined so that the shift of the optical axis of the birefringent medium extends over 2 ⁿ points. Optical device. 5. A polarization plane having a polarization plane of 90 degrees ± 45 degrees in an optical path between a combination of wobbling elements and an observation position or an imaging element.
5. A phase-modulating optical element for rotating the phase-modulating optical element by an angle, and switching the phase-modulating optical element in synchronization with a change in the polarization direction at the time of wobbling so as to align the polarization plane at the time of wobbling. An optical device according to any one of the preceding claims. 6. The optical device according to claim 5, wherein a polarizing screen is arranged on the light emission side of the combined body of the wobbling elements. 7. The optical device according to claim 5, wherein the liquid crystal used for the phase modulation optical element is a chiral smectic liquid crystal. 8. The driving cycle of each phase modulation optical element in the combination of wobbling elements is at least four times the wobbling cycle.
8. The optical device according to any one of items 7 to 7. 9. When driving each phase modulation optical element of the two combined wobbling elements, the driving cycle of each phase modulation optical element is set to four times the wobbling cycle, and the phases of the driving cycles are mutually shifted. 9. The optical device according to claim 8, wherein the optical device is shifted by 90 degrees. 10. The birefringent medium is made of a transparent substrate that shifts the optical axis depending on the polarization direction of incident light, and is disposed so as to have a uniaxial extraordinary optical axis component equivalently in the wobbling direction. The optical device according to claim 1. 11. The optical device according to claim 10, wherein the extraordinary optical axis of the birefringent medium forms an angle of 10 to 80 degrees with respect to the optical axis of the wobbling optical system. 12. The method of claim 1, wherein the birefringent medium comprises quartz.
12. The optical device according to any one of items 11 to 11.