JPH0476552B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical system in an imaging device.

[Prior art] Figure 7 shows, for example, a technical report from the Television Society.
FIG. 7 is a schematic configuration diagram showing a conventional imaging device disclosed in ED736, pages 1 to 6. 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 causes the image sensor 2 to vibrate by a distance _P0 . Here, if P _H is the horizontal pixel pitch of the image sensor 2, P ₀ =P _H /2 is selected.

FIG. 9 is an operation timing diagram of each part for explaining the operation of the imaging device of FIG. 7. FIG. 9 1 shows a field shift pulse, FIG. 9 2 shows a swing pulse, FIG. 9 3 shows a signal readout pulse, and FIG. 9 4 shows an output signal of the image sensor 2. 9. FIG. 5 is a diagram showing the case where each A and B field is viewed as one frame. As shown in FIG. 92, the phase of the swing pulse matches the field shift pulse shown in FIG. 91. As a result, signal charge accumulation in each of the A and B fields can be performed at separate positions separated by P _H /2. Correspondingly, the timing of the signal readout pulse shown in FIG. 9 is also shifted by the time T corresponding to P _H /2. As a result, as shown in FIG. 9, the conventional imaging device can obtain a high-resolution image in one cycle in which each A and B field is one frame. Note that the field shift pulse, signal reading pulse, etc. are generated by the drive circuit 4.

[Problem that the invention seeks to solve]

Since the conventional imaging device described above is configured as described above, when the imaging device is operated, the imaging device 2 is controlled by each drive circuit 4, swing pulse generation circuit 3, swing mechanism 3A, etc.
must be mechanically vibrated, and for this reason,
There were problems in that the structure of the mechanism was complicated, prone to failure, and lacked reliability.

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

[Means for solving problems]

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 vibration.

〔Example〕

FIG. 1 is a schematic configuration diagram showing an imaging device which is an embodiment of the present invention, and each reference numeral 1, 2, 4, and 5 is the same as or has the same function as the conventional device shown in FIG. 7 above. In the figure, 21 is a polarizer that creates linearly polarized light from the light incident from the lens 1, 22 is a Faraday element (first optical element) that can change the polarization angle by the magnetic field applied by the coil 24A, 23 is a birefringent plate (second optical element) such as a quartz plate that splits light 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. . 6.1 shows the field shift pulse, FIG. 6.2 shows the strength H of the magnetic field applied to the Faraday element 22, FIG. 6.3 shows the signal readout pulse, and FIG. 6.4 shows the output signal of the image pickup device 2. FIG.
2 is a diagram showing a case in which each A and B field is viewed 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 FIG. 2, each polarizer 21, Faraday element 22, and birefringent plate 23 are viewed from the direction of the A-A line, the B-B line, and the C-C line, respectively, and FIGS. It is shown in FIG. In FIG. 2, when light from the lens 1 for forming an image is incident on the polarizer 21, linearly polarized light in the vibration direction W _a shown in FIG. 3 is obtained. H _a shown in Fig. 2 is a Faraday element 22
is the direction of the magnetic field applied to the When linearly polarized light in the vibration direction W _a shown in FIG. 3 is incident on the Faraday element 22, such as lead glass, the plane of polarization of the linearly polarized light is rotated by the applied magnetic field in the magnetic field direction H _a . Note that when linearly polarized light traveling in the direction of the magnetic field H _a 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=RlH (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.
Note that equation (1) above is described in, for example, "Optical Measurement Handbook" published by Asakura Shoten Co., Ltd. In equation (1), if the strength of the magnetic field when the rotation angle θ is 0 degrees is H ₀ and the strength of the magnetic field when the rotation angle θ is 90 degrees is H ₉₀ , then when H=H ₀ , the vibration shown in Figure 4 Linearly polarized light in the direction W ₀ is obtained, and when H=H ₉₀ , linearly polarized light in the vibration direction W ₉₀ shown in FIG. 4 is obtained. Q shown in FIGS. 2 and 5 is the birefringent plate 2
This is the optical axis of No. 3. When linearly polarized light in the vibration direction W _a enters the birefringent plate 23, the ordinary ray shown in FIG.
L ₀ is obtained. Furthermore, when linearly polarized light in the vibration direction W ₉₀ is incident on the birefringent plate 23, an extraordinary ray L _E shown in FIG. 5 is obtained. Let the distance between the ordinary ray L ₀ and the extraordinary ray L _E be P, and the above P in the birefringent plate 23 shown in each _FIG . 1 and _FIG . (indicates pixel pitch). The phase of 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. 61. Due to the above-described operation, in the imaging device according to the present invention, signal charge accumulation in each of the A and B fields is performed at a position separated by P _H /2 with respect to the relative position of the incident image and the pixel of the imaging device 2. I can do it. 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. Correspondingly, the timing of the signal readout pulse shown in FIG.
It is shifted by a time T corresponding to P _H /2. As a result, as shown in FIG.
It becomes possible to obtain high-resolution images at regular intervals. The drive circuit 4 shown in FIG.
The strength H of the magnetic field applied to is also controlled. Furthermore, the signal processing circuit 5 shown in FIG. 1 is a circuit for processing the signal from the image sensor 2 and converting it into a video signal.

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 Faraday element 22 was used as the first optical element, but it is an optical element that can rotate the polarization plane of transmitted light by changing the strength H of the applied magnetic field. Any optical element may be used as long as it exists.

〔Effect of the invention〕

As explained above, the present invention includes an imaging device in which the imaging optical system includes a polarizer that creates linearly polarized light, and a first optical element having a magneto-optic effect is inserted between the polarizer and the imaging element, Furthermore, a second optical element that splits the light into independent polarization components is inserted between the first optical element and the image sensor, so compared to conventional devices of this type, the image sensor It is possible to realize a high-resolution surface image without mechanically vibrating the image pickup device, and therefore, it is possible to obtain an imaging device with fewer failures and high reliability, which is an excellent effect.

[Brief explanation of the drawing]

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 to explain the operation of the imaging device, FIG. 7 is a schematic configuration diagram showing a conventional imaging device, and FIG. 8 is a
FIG. 9 is a diagram for explaining the operation of some components in the imaging device shown in FIG. 7, and FIG. 9 is an operation timing diagram of each part for explaining the operation of the imaging device shown in FIG. In the figure, 1...lens, 2...imaging element,
4...Drive circuit, 5...Signal processing circuit, 21...
Polarizer, 22...Faraday element, 23...birefringence plate, 24...magnetic field generation circuit, 24A...coil. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. The imaging optical system includes a polarizer that produces linearly polarized light,
A first optical element having a magneto-optical effect that exhibits anisotropy due to a magnetic field is inserted between this polarizer and an image sensor configured with a plurality of pixels arranged two-dimensionally. An imaging device characterized in that a second optical element that splits light into independent polarization components is inserted between the first optical element and the imaging element. 2. The spatial sampling area is increased 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. An imaging device according to claim 1, characterized in that: 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.