JPS61247168A - Image pickup device - Google Patents

Abstract

PURPOSE:To improve the resolution with simple constitution by using an electrooptical element and a dual refraction means by which a polarized characteristic is controlled so as to displace selectively an image to each photodetector element in the image pickup means. CONSTITUTION:Incident lights A and B are made incident to an image pickup means 3 comprising plural photodetectors via a double refraction plate 2 and the electrooptical element 1 whose polarization characteristic is changed by a voltage fed to electrodes 4, 4' and recorded to a memory circuit 13 as a picture signal. In applying the 1st voltage to the element 1, the incident light is rotated by 90 deg., polarized at the double refraction plate 2 by a prescribed plate 2 and the result is made incident to the image pickup element 3. Thus, the incident light B is formed to the photodetector C. In making the applied voltage to the element 1 zero, the incident light is not rotated and not polarized by the dual refraction plate 2, then the incident light A is formed to the photodetector C. Thus, the digital interpolation of the image pickup element 3 is attained by switching the applied voltage to improve the resolution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solid-state high-resolution imaging device for increasing the resolution of a finite aperture imaging element.

[Summary of disclosure]

This specification and drawings describe a solid-state high-resolution imaging device in which an image for each light-receiving element within the imaging device can be selectively displaced by a combination of an electro-optical element capable of controlling polarization characteristics and a birefringence device. This invention discloses a technique for obtaining a completely solid-state, high-resolution imaging device.

[Prior art]

Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 60-18958, the resolution is doubled by using a piezo element to vibrate a solid-state image sensor by a half-pixel pitch. Or, as in Japanese Patent Laid-Open No. 59-53978, there is a double image system in which two rows of pixels are overlapped to receive an image using birefringence.However, in the former method, there is a limit to the piezo vibration cycle. Moreover, the latter has many mechanical parts, is expensive, and requires precision in positioning and assembly. On the other hand, increasing the formation density of photoelectric conversion pixels in order to improve the resolution of the solid-state imaging device itself not only involves technical difficulties, but also involves deterioration of characteristics and a significant increase in cost.

An object of the present invention is to provide an imaging device that can solve the above-mentioned drawbacks.

In particular, it is an object of the present invention to provide an imaging device that can operate easily and stably.

[Means to solve the problem]

Hereinafter, the present invention will be explained in detail based on Examples.

In the present invention, an electro-optical element whose polarization characteristics can be controlled according to voltage and a birefringence means are arranged in front of an imaging means, and a voltage switching means is further provided to control the electro-optical element.

[Effect]

When a predetermined first voltage is applied to the polarizing means, linearly polarized incident light is polarized at λ=90°.

This light is incident parallel to the main surface of the birefringent means and is deflected as an extraordinary ray.

On the other hand, when a predetermined voltage ts2 is applied to the polarizing means, the light incident on the polarizing means is not polarized and is incident perpendicularly to the main surface of the birefringent means. Then, it becomes an ordinary ray and travels straight without being deflected.

Therefore, simply by switching the voltage applied to the polarizing means, the relative relationship between the image and the imaging means can be changed by a predetermined amount.

If this amount of displacement is selected as H of the pixel pitch of the imaging means, the resolution can be doubled.

〔Example〕

Fig. 1 is a diagram showing a first embodiment of the present invention, and Figs. 1 to 4 are diagrams showing embodiments of the present invention. PO4).

ADP (NH4H2PO4), LiNb0. '
&E Pockels cell made of O crystal material and ship base material with liquid crystal TI effect. 4,4'
is an electrode, which is bonded to the polarizing element with a conductive adhesive or the like. Reference numeral 2 denotes a birefringent plate as a birefringent means, which is made of a birefringent material such as calcite, or a Unirastone prism or a Savard plate.

This birefringent plate is cut along a plane with a fixed crystal axis, and its entrance surface is polished. Reference numeral 3 denotes an image sensor, which is an MO8 image sensor-1 COD image sensor, an Amol 7A silicon sensor, etc., and includes a plurality of light-receiving elements. Reference numeral 11 designates a voltage control circuit as a voltage switching means for sequentially switching the voltage applied to the polarizing element in synchronization with the drive timing of the image sensor, 12 an image sensor drive circuit, and 13 a memory circuit. Figure 2 shows the positional relationship between the sample pixel and the light-receiving element, and 3' is the object pixel row that is imaged on the row 2' of the light-receiving element when the first voltage is applied between 4 and 4' to the polarizing element IK. Indicates the location of Further, when a second voltage is applied to the deflection light element 1, the light from the sample pixel enters the light receiving element without being deflected.

That is, when the first voltage (half-wavelength voltage) vl is applied to the polarizing element 1, the linearly polarized incident light is rotated by 90 degrees. This light is incident parallel to the main surface of the birefringent plate 2 and forms an extraordinary ray of about 5
subject to a deflection of 90'. For example, in order to rotate 90 degrees with 10 parrot Pockels effect elements, the first voltage (for example, 2K
When Y) is applied, the imaging position can be shifted by about 20 μm when a birefringent plate with a thickness of 0.2 mm is used.

On the other hand, the voltage applied to the polarizing element is set to 0 volts (second voltage).
When v2, no polarization occurs within the polarizing element, and the light is incident perpendicularly to the main surface of the birefringent plate] - becomes an ordinary ray and travels straight without being deflected.

As a result, digital interpolation of the image sensor is possible by switching the applied voltage, and the conventional resolution can be doubled.

As described above, according to this embodiment, since the digital deflection is used, synchronization is easier to achieve compared to the conventional analog deflection system in which pixels are scanned on a sweeper to receive images, and the input signal rises more clearly. Become. In addition, polarizing materials are easily available at low cost (particularly in the case of liquid crystal, the thickness is only 1 fi), and the applied voltage can be small (several volts), making it suitable for incorporating into equipment or mounting on equipment.

In addition, a half-wavelength polarizing element (LiM'
bO, YPI, ZT) t[Even in the case of A, the half-wave voltage (applied voltage that rotates the linear polarization direction by 90°) may be 2 to 5 V for a polarizing element with a thickness of 10 degrees.

Also, in order to deflect the birefringent plate by 5°90', it will take about 0.2 degrees. Therefore, the overall structure in which the two are superimposed can be made thin, with a low voltage, a small current, and can be easily manufactured at low cost using easily available materials.

Next, FIG. 3 is a diagram showing a second embodiment of the present invention, and is an example in which four sets of digital deflectors according to the present invention are arranged one on top of the other. , birefringent plate 20
Combinations: 1. In Figure 1, a combination of a polarizing element 5 and a birefringent plate 60 for deflecting to the + side of the two axes, and a combination of a polarizing element 7 and a birefringent plate 80 for deflecting to one side of the X axis.

Polarizing element 9 and birefringent plate 10 for deflecting to one side of the z-axis
It has a combination of.

FIG. 4 is a diagram showing the positional relationship between the sample pixel and the light receiving element 5' in this embodiment.

By applying the half-wave voltage V1 to the polarizing elements j, 5, and 7.9 in the order shown in the table below, the sample pixels imaged on the light receiving element 3' become 2', 2', and 7.9 as shown in the fourth figure. 6',
Rotate like 8', 10'.

This switching using the half-wave voltage v is performed for each field within the vertical blanking period, and the output of each field is stored in the corresponding memory address in the memory circuit.

Next, FIG. 5 is a diagram showing a third embodiment of the present invention, in which two sets of deflectors having different shift amounts in the same direction are arranged.

When linearly polarized light is incident on the polarizing element 14 with the half-wave voltage V1 applied, this polarized light is rotated by 90 degrees and deflected by one step by the birefringent plate 12.

Next, a large second-stage deflection is performed by a birefringent plate 14, which is thicker than the birefringent plate 12, and the sample pixel at position 18 is input to the light receiving element 3' on the image sensor.

In this way, if we make 17 birefringent plates twice as thick as birefringent plate 15 by combining two stages of deflectors in the same direction, the thickness will be 18.17.
You can arbitrarily input four equally spaced pixels such as ', 15', and 5'. That is, 18 applies vl to both of the two polarizing elements, 17' applies vl only to the polarizing element 16, and 15' applies vl only to the polarizing element 14, thereby inputting them to the light receiving element 6'. I can do things.

Further, 5' can be inputted from K by applying 0pol (Vz) to both polarizing elements.

By combining them, several times the resolution can be obtained even in two-dimensional directions. Moreover, the switching speed of the element is 10 ne
, switching of the power supply can be performed at a high speed of several tens of μ8. Moreover, even if they are stacked together, they are as thin as several 10,101 layers at most, making them suitable for miniaturization and weight reduction. Furthermore, unlike conventional deflectors that utilize the Pockels effect, which are analog, the rise υ of the image signal received by the image sensor is sharper because it is a digital system that forms an image of one pixel only on the image sensor. In addition, the controller for power supply and switching becomes simpler because there is no need for a polarity reversal mechanism. In addition, especially if a liquid crystal polarizing element is used, an applied voltage of several volts is sufficient, and the power supply

[Brief explanation of drawings]

FIG. 1 is a diagram of a first embodiment of the present invention using a one-dimensional, one-stage deflector, FIG. The figure shows the basic configuration of Figure 1.
Rotate 0 degrees at a time and combine 4 pieces in the X and Z axis directions.
4 is a diagram showing an example of quadruple resolution according to the second embodiment of the present invention, in which dimensional pixels are sequentially captured by changing the applied voltage. FIG. FIG. 5 is a position diagram showing the order and arrangement, and FIG. 5 is a third embodiment diagram showing an example of multi-stage deflection in which four pixels are input by deflecting in two stages in the same direction. 1.5, 7, 9, 14, IS... Polarizing element as an electro-optical element 2.6, 8, 10, 15.17... Birefringence plate 3 as a birefringence means... As an imaging means Imaging device 4...Electrode Invention/l Shu 3 Tsubaki Asahi J1 Bacteria Yu 5 Diagram

Claims (1)

[Scope of Claims] An electro-optical element for controlling the polarization characteristics of incident light according to a voltage, a birefringence means combined with the electro-optical element, and an electro-optical element for controlling the polarization characteristics of incident light according to a voltage. An imaging device comprising: an imaging means for receiving light; and a voltage switching means for changing the polarization characteristic of the electro-optical element with respect to the birefringence characteristic of the birefringence means.