JPS61267462A - Image pickup device - Google Patents

Abstract

PURPOSE:To obtain images of high resolution without oscillating mechanically an image pickup element by providing an image pickup optical system with a polarizer which makes a linearly polarized light and inserting the first optical element having the magnetooptic effect and the the second optical element which divides light into polarized light components independently of each other. CONSTITUTION:When a linearly polarized light is made incident on a Farady element 22, the plane of polarization of the linearly polarized light is rotated by impression of a magnetic field Ha. The distance between ordinary rays L0 and extraordinary rays LE is denoted as P, and the value P of a double refracting plate 23 is set to PH/2 (PH is the horizontal picture element pitch of an image pickup element 2). The phase of the change of the intensity of the magnetic field impressed to the Farady element 22 is allowed to coincide with a field shift pulse. By this operation, signal electric charges in fields A and B are stored in positions PH/2 distant from each other with respect to the relative position between the incident image and the image of the image pickup element 2. The timing of a signal reading pulse is shifted by a time T corresponding to PH/2 in accordance with said positions. Thus, the image of high resolution is obtained in cycle with fields A and B as one frame.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical system in a photographing yJ apparatus.

[Conventional technology]

Figure 7 shows 1 For example, Television Society Technical Report ED736
．． It is a schematic block diagram which shows the conventional imaging device disclosed on the 1st - 6th page. In the figure, 1 is a lens for forming an image, 2 is an image pickup device, 3 is a swing pulse generation circuit, 3A is a swing mechanism, 4 is a drive circuit, and 5 is a signal processing circuit.

FIG. 8 is a diagram for explaining the operation of a part of the configuration in the imaging device of FIG. 7. As shown in the figure, the swing mechanism 3A moves the υ image sensor 2 at a distance P. Let it vibrate only. Here, if PH is the horizontal pixel pitch of the image sensor 2, then P is selected.

FIG. 9 is an operation timing diagram of each part for explaining the operation of the imaging device of FIG. 7. Figure 9 (1) shows the field shift pulse, Figure 9 (2) shows the swing pulse, Figure 9 (3) shows the signal readout pulse, and Figure 9 (4) shows the output signal of the image sensor 2. FIG. 9(5) is a diagram showing the case where the A and B fields are viewed as one frame. Figure 9 (2
), the phase of the swing pulse is as shown in Figure 9 (1
) corresponds to the field shift pulse shown in (). As a result, it can be performed at each of the A and B positions. Correspondingly, the timing of the signal readout pulse shown in FIG. 9(3) is also changed as shown in FIG. 9(5) in the conventional imaging device.

A high-resolution image can be obtained in 91 cycles with each A and B field as one frame.

[Problems to be Solved by the Invention] Since the conventional imaging device as described above is configured as one or more, when operating the imaging device, each drive circuit 4. Swing pulse generation circuit 3, swing mechanism 3
For this reason, the image sensor 2 must be mechanically vibrated by A or the like.

There were problems in that the structure of the mechanism was complex, prone to failure, and lacked reliability.

The present invention was made to solve such problems, and an object of the present invention is to obtain an imaging device that can realize high-resolution images without mechanically moving an imaging element.

[Next method to solve the problem]

The imaging device according to the present invention includes a polarizer that creates linearly polarized light in the imaging optical system, a first optical element having a magneto-optic effect is inserted between the polarizer and the imaging element, and the first optical element has a magneto-optic effect. A second optical element that splits light into independent polarization components is inserted between the first optical element and the image sensor.

[Effect]

In the imaging device of the present invention, the first optical element having a magneto-optic effect can change the rotation angle of its plane of polarization by changing the magnetic field applied thereto, and as a result, the rotation angle of the plane of polarization can be changed. High-resolution images can be achieved without mechanical imaging.

〔Example〕

FIG. 1 is a schematic configuration diagram showing an imaging device that is an embodiment of the present invention, and each reference numeral 1, 2, 4, and 5 is the same as the conventional device shown in FIG. is a polarizer that creates linearly polarized light from nine elements incident through lens l, 22
23 is a Faraday element (first optical element) that can change the polarization angle by the magnetic field applied by the coil 24A, and 23 is a birefringent plate such as a filter crystal plate (second optical element) that divides the polarization angle into independent polarization components. 24 is a magnetic field generating circuit including a coil 24A.

2 to 5 are diagrams for explaining the operation of the imaging device shown in FIG. 1, respectively, and FIG. 6 is an operation timing chart of each part for explaining the operation of the imaging device of FIG. 1. . FIG. 6(1) shows the field shift pulse, FIG. 6(2) shows the magnetic field 9 strength H applied to the 7Alade element 22, and FIG. Pulse 75-
FIG. 6(4) is a diagram showing the output signals of the image sensor 2, and FIG. 6(5) is a diagram showing the A and B fields combined as one frame.

Next, the operation of the imaging apparatus shown in FIG. 1, which is an embodiment of the present invention, will be described. In Figure 2, each polarizer 2
1. Faraday element 22. The birefringent plates 23 are each A-
The causes seen from the direction of A line, B-B line, and C-C line are
4 and 5. In FIG. 2, when the light from the lens 1 for forming one image is incident on the polarizer 21, linearly polarized light in the vibration direction W3 shown in FIG. 3 is obtained. Ha shown in FIG. 2 is the direction of the magnetic field applied to the Faraday element 22. In FIG. Vibration direction W shown in Figure 3
When linearly polarized light of jL is incident on a Faraday element 22 made of, for example, lead glass, the plane of polarization of the linearly polarized light is rotated by the applied magnetic field in the direction of the magnetic field HjL. Note that when linearly polarized light traveling in the direction H1 of the magnetic field is incident on the Faraday element 22, the polarization plane of the transmitted light is rotated, and the rotation angle θ is obtained by the following equation.

θ-RIH,------...Mountain......
...mountain...river...mountain...(1
) Here, l is the thickness of the Faraday element 22, H is the strength of the magnetic field, and R is the Verdet constant. The above formula (1) is described in, for example, "Optical Measurement Handbook" published by Asakura Shoten Co., Ltd. In Figure 2, if the strength of the magnetic field at which the rotation angle θ becomes 'O degrees is H, and the strength of the magnetic field at which the rotation angle θ is 90 degrees is Hoo, then H
-f(, , a normal, line-side light in the vibration direction Wa shown in FIG. 4 is obtained, and when H"He., a linearly polarized light in the vibration direction W, shown in FIG. 4 is obtained.

Q shown in FIG. 5 is the optical axis of the birefringent plate 23.

When linearly polarized light in the vibration direction W& enters the birefringent plate 23,
An ordinary ray L0 shown in FIG. 5 is obtained. Also, the vibration direction W
When the linearly polarized light o0 enters the birefringent plate 23, an extraordinary ray LE shown in FIG. 5 is obtained. Ordinary ray L and extraordinary ray L
Let P be the distance from 0, and the above P in the birefringent plate 23 shown in each FIG. 1 and FIG.

). The phase of the change in the strength H of the magnetic field applied to the Faraday element 22 is made to match the field shift pulse shown in FIG. 6(1). With the above-described operation, the image pickup device according to the present invention can accumulate signal charges in each of the A and B fields at a position that is adjacent to the incident image and the image pickup element layer. That is, by temporally changing the strength H of the magnetic field applied to the Faraday element 22 and temporally changing the relative positional relationship between the incident optical image and the pixels of the image sensor 2, the spatial sampling area can be expanded. Can be increased. Corresponding to this, the signal readout pulse is shifted as shown in FIG. 6(3). As a result, as shown in Figure 86 (5).

The imaging device according to the present invention can obtain a high-resolution image in one cycle in which each A and B field is one frame. The drive circuit 4 shown in FIG. 1 is a circuit for driving the image pickup device 2, and also controls the strength H of the magnetic field applied to the 7-Alade element 22. Furthermore, the signal processing circuit 5 shown in FIG. 1 processes the signal from the image sensor 2,
This is a circuit for generating video signals.

In the above embodiment, any method may be used to change the strength H of the magnetic field applied to the Faraday element 22 as the first optical element.

Further, in the above embodiment, a case was explained in which the 7 Allade element 22 was used as the first optical element, but the optical element can rotate the polarization plane of the transmitted light by changing the strength H of the applied magnetic field. Any optical element may be used.

〔Effect of the invention〕

As described above, the present invention provides an imaging apparatus including a polarizer that produces linearly polarized light in an imaging optical system.

A first optical element having a magneto-optical effect is inserted between the polarizer and the image sensor, and further, between the first optical element and the image sensor, light is divided into independent polarization components. Since the second splitting optical element is inserted, compared to conventional devices of this type, it is possible to realize high-resolution images without mechanically vibrating the image sensor.
This provides an excellent effect in that a highly reliable imaging device with fewer failures can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an imaging device that is an embodiment of the present invention, FIGS. 2 to 5 are diagrams for explaining the operation of the imaging device shown in FIG. 1, and FIG. FIG. 1 is an operation timing diagram of each part for explaining the operation of the imaging device; FIG. 7 is a schematic configuration diagram showing a conventional imaging device;
FIG. 8 is a diagram for explaining the operation of some components in the imaging device of FIG. 7, and FIG. 9 is an operation timing diagram of each part for explaining the operation of the imaging device of FIG. 7. . In the figure, 1...lens, 2...imaging element, 4...
... Drive circuit, 5... Signal processing circuit, 21... Polarizer, 22... Faraday element, 23... Birefringent plate,
24... Magnetic field generation circuit, 24A... Coil. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (4)

[Claims] (1) The imaging optical system is equipped with a polarizer that creates linearly polarized light, and exhibits anisotropy due to a magnetic field between this polarizer and an image sensor composed of a plurality of pixels arranged two-dimensionally. A first optical element having a magneto-optical effect is inserted, and a second optical element that splits light into independent polarization components is inserted between the first optical element and the image sensor. imaging device. (2) By temporally changing the magnetic field applied to the first optical element and temporally changing the relative positional relationship between the incident optical image and the pixels of the image sensor, the spatial sampling area can be expanded. The imaging device according to claim 1, wherein the imaging device has an increased number of pixels. (3) The imaging device according to claim 1, wherein a Faraday element is used as the first optical element. (4) The imaging device according to claim 1, wherein a birefringent plate is used as the second optical element.