JPS5864874A - Image pickup device with radiant-ray-resistance - Google Patents

Abstract

PURPOSE:To make the device light weight, and to prevent the deterioration of performance of an image pickup element due to radiant-rays, by surrounding the image pickup element and a reflecting mirror with a case made of a material attenuating radiant-rays, and locating the image pickup element at a location where no radiant-rays are made incident from an incident window of the case. CONSTITUTION:An optical axis of an incident light 1 is changed at a reflecting mirror 11 and the light is made incident to an image pickup element 3. Further, radiant-rays 7 in the same direction as the light 1 pass through the reflecting mirror 11 and go straight, then the light does not reach the element 3, and the radiant-rays from the different direction as the light 1 are attenuated with a radiant-ray-resistant case 12 and does not reach the element 3. In the case 12, an incident window 14 to which the light 1 is incident, is provided at a part between an optical system 2 and the reflecting mirror 11, but the radiant-rays from the window 14 do not reach the element 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a radiation-resistant imaging device that prevents deterioration of the performance of an imaging device due to radiation.

Conventionally, there has been a device of this type as shown in FIG.

In the figure, (1) is an incident light beam, (2) is an optical system consisting of lenses, etc., (3) is an image sensor, (4) is an electronic circuit that processes the signal of this image sensor (3), and (5) is A front mirror that changes the optical axis of the incident ray controller 1), the depth is the optical axis after the incident ray (1) is reflected by the front mirror (5), (6) (7) is the radiation, (8) is the attenuator of the radiation (9) is a radiation-resistant case made of lead or the like as a material;
αl is radiation incident at an angle α2 with respect to the optical axis a.

Next, the operation will be explained.

An incident light beam (1) has its optical axis changed by a front mirror (5) and enters an image sensor (3) via an optical system (2).

The image sensor (3) converts the incident light beam (1) into an electrical signal, and the electronic circuit (4) can image the electrical signal by appropriately processing the electrical signal.

By the way, when the image sensor (3) is exposed to radiation, its performance deteriorates. For this reason, an imaging device consisting of an imaging device (3), an optical system (2), and an electronic circuit (4) is mounted in a case (8) made of a material such as lead or iron that can attenuate radiation. Let's chant as shown in the diagram. In this case, the radiation (6) passes straight through the front mirror (5) and does not enter the image sensor (3).

In addition, radiation II (71 is a radiation-proof case (8) and a surface mirror (
5) and enters the image sensor (3), but if the case (8) is made sufficiently thick, the radiation incident on the image sensor (3) can be attenuated.

However, radiation such as radiation (9) αe, which is incident at an angle α1 or more and α2 or less with respect to the optical axis a, is not attenuated by the case (8) and directly passes through the image sensor (3).
incident on . That is, a certain amount of radiation is always incident on the image sensor (3), whether during imaging or not. Therefore, radiation incident at such an angle is
) can be layered attenuated by increasing the area of the surface mirror (5), but the whole device becomes very heavy.

Conventional radiation-resistant imaging devices are constructed as described above, so if lead, iron, or the like is used as the material for the radiation-resistant case, the case will cover the entire imaging device, resulting in a very heavy weight. There was a drawback. Also,
Even when the image is not being captured, radiation incident at a predetermined angle directly enters the imaging device, and even if attempts are made to increase the area of the surface mirror of the case as a countermeasure, the weight of the device will also increase accordingly, so this is not practical. This poses a problem in that it is impossible to implement, and it is extremely difficult to attenuate the radiation.

This invention was made in view of the problems of the conventional ones as described above, and it surrounds the image sensor and the reflecting mirror with a case made of a material that attenuates radiation dose, such as lead. It is an object of the present invention to provide a light-weight, radiation-resistant imaging device that can completely prevent performance deterioration of an imaging element due to radiation by providing the imaging device at a position where radiation from the entrance window does not enter.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows a radiation-resistant imaging device according to an embodiment of the present invention, and in the figure, the same reference numerals as in FIG. 1 indicate the same elements as in FIG. 1. αD is a reflecting mirror that changes the optical axis of the incident light beam (1), and ■ is a radiation-resistant case, which is made of lead, iron, or the like. Also, 0 is radiation.

Next, the operation will be explained.

The incident light beam (1) has its optical axis changed by the reflecting mirror αυ and enters the image sensor (3). On the other hand, regarding radiation, radiation (7) from the same direction as the incident light beam (1) passes through the reflecting mirror I and proceeds straight, so it does not enter the image sensor (3). In addition, radiation from other directions (not shown) is attenuated by the radiation-resistant case @, and the image sensor (
3) is not incident. By the way, in case @, the part between the optical system (2) and the reflecting mirror 0 is the entrance window number 0 through which the incident light beam (1) enters, but the radiation from this entrance window αω is A sufficient distance is provided between the imaging element (3) and the reflection -0 so that the reflection -0 does not enter the element (3).

If this is done, the radiation α3 that enters through the entrance window α [present] will not enter the image sensor (3). As a result, this device can completely prevent performance deterioration of the image sensor (3) due to radiation.

The reflecting mirror used in the above embodiments may be made of a glass surface coated with a metal such as aluminum, or any other material that reflects medium light.

As described above, according to the present invention, the imaging device and the reflecting mirror are surrounded by a case made of a material that attenuates radiation, and the imaging device is installed in a position where radiation from the entrance window of the case does not enter. Because of this structure, there is no deterioration in the performance of the image sensor due to radiation, and there is an effect that a significant weight reduction can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional radiation-resistant imaging device, and FIG. 2 is a sectional view showing a radiation-resistant imaging device according to an embodiment of the present invention. (2)...Optical system, (3)...Image sensor, I...
Reflector, @...case. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent 1 Noshin - Figure 1 Figure 2

Claims (1)

[Claims] (1) A reflecting mirror that changes the optical axis of the incident light that has passed through the optical system, an image sensor installed on the optical axis of the incident light whose optical axis has been changed by this reflecting mirror, and the image sensor that directly enters the incident light through its entrance window. A radiation-resistant imaging device comprising: a radiation-resistant case that surrounds the image sensor at a position where almost no radiation enters the image sensor.