JPH0449262B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a cooled photoelectric conversion device, and in particular to a cold photoelectric conversion device that limits background radiation from entering an infrared receiving element array mounted on a cooling head in the device. This concerns the structure of the shield.

(b) Background of the Technology Photoelectric conversion elements for infrared detection, which are generally made of semiconductors, produce an output that corresponds to the amount of incident light, and they have the property of not operating well unless they are cooled to a temperature much lower than room temperature. Therefore, for example, the photoelectric conversion element can be stored in a vacuum-insulated container using a vacuum-insulated container with a dewar structure consisting of an outer cylinder partially having an infrared-transmitting window and an inner cylinder having a cooling head opposite the infrared-transmitting window. It is installed on a cooling head on the vacuum side inside the container, and is operated by cooling it to a predetermined low temperature with liquid nitrogen or the like via the cooling head.

On the other hand, the viewing angle for the photoelectric conversion element depends on the shape of the field-of-view determining opening in the cold shield provided on the front of the element, which defines the range of incident light, and the distance between the opening and the element's light-receiving surface. It is determined that

This cold shield is further cooled to an extremely low temperature together with the photoelectric conversion element to prevent background radiation from entering outside the detection field of view.

(c) Prior Art and Problems By the way, as a cold shield for a conventional multi-element infrared sensing element, for example, an infrared sensing element array arranged one-dimensionally, for example, the arrangement of each of the sensing elements of the infrared sensing element array is useful. Because pits are usually extremely small, ranging from a few μm to several tens of μm,
Since it is difficult to arrange individual field-of-view determining openings corresponding to each light-receiving element in terms of manufacturing and structural reasons, they are arranged one-dimensionally as shown in the schematic perspective view of Figure 1. Infrared receiving element array 1
A cold shield 3 is placed so that the rectangular slit-shaped field-of-view determining opening 4 is parallel to the entire light-receiving surface of the cold shield 3 and is spaced apart from it by a predetermined distance.

However, cold shield 3 as mentioned above
Regarding the shape of the field-of-view determining opening 4, the effective viewing angles of the light-receiving elements 2a at the center and the light-receiving elements 2b at both ends of the light-receiving element array 1 are different. That is, there is a problem in that so-called shading occurs when the amount of light incident on the light receiving element array 1 decreases at both ends. Therefore, the signal output of each of the light receiving elements 2 becomes non-uniform,
The structure is similar to that of arranging the light receiving elements 2 whose sensitivity decreases from the center toward both ends, which is an undesirable phenomenon for the infrared light receiving element array 1.

Therefore, by increasing the distance between the light-receiving surface of the light-receiving element array 1 and the field-of-view determining aperture 4 of the cold shield 3, the shading phenomenon can be considerably improved, but in this case, the structure of the cold shield 3 is There is a problem in that the size of the device increases.

(d) Purpose of the Invention In view of the above-mentioned conventional drawbacks, the present invention improves the visual field determination opening of the cold shield to have a blind shape for the entire light receiving element surface of the one-dimensionally arranged infrared receiving element array. It is an object of the present invention to provide a novel cooled photoelectric conversion device that equalizes the viewing angle for each light-receiving element surface of the infrared light-receiving element array, thereby eliminating the shading phenomenon.

(e) Structure of the Invention According to the present invention, this object comprises a cold shield provided with an aperture for determining the field of view that defines the range of incident light on the front surface of the infrared receiving element array; The shield has a plurality of light-shielding partition plates arranged in parallel at regular intervals perpendicular to the light-receiving surface of the light-receiving element array and intersecting with the arrangement direction of the light-receiving element array in the opening thereof, from the light-receiving surface. The effective viewing angle of each light-receiving element is determined by the distance and width of the light-shielding partition plates and the installation height from the light-receiving surface of the light-receiving element array. This is achieved by providing a cooled photoelectric conversion device characterized in that it is set through a gap between plates.

(f) Embodiments of the invention Examples of the invention will be described in detail below with reference to the drawings.

FIG. 2 is a schematic perspective view showing an embodiment of the structure of the opening of the cold shield in the cooled photoelectric conversion device according to the present invention, and FIG. 3 is a schematic perspective view of the cold shield of FIG. FIG. 3 is a schematic diagram illustrating the relationship between the opening and the entire light-receiving element surface of the infrared light-receiving element array.

First, as shown in FIG. 2, in the present invention, a cooling head is arranged one-dimensionally on a cooling head (not shown), and faces at a predetermined height with respect to all the light-receiving element surfaces of the infrared light-receiving element array 1. - The shape of the field-of-view determining opening 4 of the shield 3 is set, for example, in the opening 4 so that it is perpendicular to the light-receiving surface of the light-receiving element array 1 and perpendicular to the arrangement direction of the light-receiving element array 1. As shown in the figure, a plurality of light-shielding partition plates 21 arranged in parallel at regular intervals are arranged at a predetermined height position apart from the light-receiving surface. However, in this case, the predetermined interval portions 22 formed by the light-shielding partition plates 21 do not need to correspond individually to the two surfaces of the light-receiving elements of the opposing light-receiving element array 1.

Therefore, as described above, the light receiving element array 1
By configuring the visual field determining opening 4 of the cold shield 3 in a blind shape, the light receiving element array 1 is formed as shown in the schematic diagram of FIG.
The viewing angle at each light-receiving surface 31 is uniformly defined by each light-shielding partition plate 21 . And for example,
If the width L of each light-shielding partition plate 21 in the figure is 2, the interval D between each light-shielding partition plate 21 is 1, and the height H of the light-shielding partition plate 21 with respect to the element surface is 4, then the element surface directly below the light-shielding partition plate 21 The effective viewing angle at A is 27.72°,
Further, the effective viewing angle on the element surface B directly below the center between the light-shielding partition plates 21 is 27.48°, which hardly fluctuates.
Therefore, to configure the shape of the field-of-view determining opening 4 of the cold shield 3, the width L of the light-shielding partition plate 21, the distance D between each light-shielding partition plate 21, and the height of the light-shielding partition plate 21 with respect to the element surface are determined. By appropriately selecting H, it is possible to easily determine the viewing angle required for the photodetector array 1, and the light entering the opening 4 of the cold shield 3 via a common optical system (not shown) can be easily determined. The light is uniformly received by each light receiving element 2 of the light receiving element array 1 through each gap of the light shielding partition plate 21 in the opening 4. Therefore, the shading phenomenon that occurs from the light receiving element 2a at the center of the light receiving element array 1 to the light receiving elements 2b at both ends is also eliminated.

In the above embodiments, a one-dimensional array of infrared light-receiving elements has been described as an example, but the present invention is of course not limited to this, and is equally applicable to a two-dimensional array of infrared light-receiving elements. be.

(g) Effects of the Invention As is clear from the above explanation, according to the cooled photoelectric conversion device of the present invention, the cold photoelectric conversion device of the infrared light receiving element array is arranged so as to face all the light receiving element surfaces.
A plurality of light-shielding partition plates are arranged in parallel at predetermined intervals in a blind state in a field-of-view determining opening of the shield in a manner that intersects with the arrangement direction of the light-receiving element array, and at a height position spaced apart from the light-receiving element surface. With this configuration, light entering the field-of-view determining opening of the cold shield through a common optical system passes through each gap of the plurality of light-shielding partition plates provided in the opening and passes through the light-receiving element array. Since the light is incident on each light-receiving element, it becomes possible to define the effective viewing angle on each light-receiving element surface on the light-receiving element array to be substantially constant, and the conventional shading phenomenon is eliminated. Therefore, uniform output signals can be obtained across each light receiving element, and the performance of the cooled photoelectric conversion device can be greatly improved. It also has excellent advantages, such as the ability to make the cold shield compact.

[Brief explanation of the drawing]

Figure 1 shows a conventional cooling type photoelectric conversion device.
FIG. 2 is a schematic perspective view illustrating the structure of the opening of the cold shield; FIG. The figure is a schematic diagram illustrating the relationship between the opening of the cold shield and the entire light-receiving element surface of the infrared light-receiving element array in FIG. 2 according to the present invention. In the drawings, 1 is an infrared receiving element array; 2 is an infrared receiving element array;
2 is a light receiving element, 2a is a central light receiving element, 2b is a light receiving element at both ends, 3 is a cold shield, 4 is an aperture for determining the field of view, 21 is a light shielding partition plate, 22 is a predetermined interval part, 31 is each light receiving element Show the face.

Claims (1)

[Claims] 1. A cold shield 3 is provided in front of the infrared light receiving element array 1 and has an aperture 4 for determining the field of view that defines the range of incident light. array 1
A plurality of light-shielding partition plates 21 are arranged in parallel at regular intervals perpendicular to the light-receiving surface and intersecting the arrangement direction of the light-receiving element array 1 at a height H apart from the light-receiving surface. The spacing D and width L of the light shielding partition plate 21 and the light receiving element array 1
A cooled photoelectric conversion device characterized in that the effective viewing angle of each light-receiving element 2 is set through the gaps between a plurality of adjacent light-shielding partition plates 21 by the installation height H from the light-receiving surface.