JPS6412150B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a cooling type photoelectric conversion device, and in particular to a phenomenon of shedding of the amount of light incident on an array of infrared light receiving elements arranged one-dimensionally on a cooling head in the device. It concerns the structure of the cold shield, which can be significantly reduced.

(b) Background of the Technology Photoelectric conversion device 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 manufactured using a vacuum insulated container with a dewar structure consisting of an outer cylinder partially provided with an infrared transmitting window and an inner cylinder provided with a cooling head opposite the infrared transmitting window.
It is installed on the vacuum-side cooling head in the vacuum insulation 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. Since the pitch is usually extremely small, ranging from several μm to several tens of μm, it is necessary to provide a separate aperture for determining the field of view corresponding to each light-receiving element. Since it is difficult to align each light-receiving element with the opening, the entire light-receiving surface of the one-dimensionally arranged infrared light-receiving element array 1 is difficult to align. A cold shield 3 having a rectangular slit-shaped field-of-view determining opening 4 is disposed opposite to the cold shield 3 with the opening 4 parallel to the field-of-field determining opening 4 and spaced apart 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, in which the amount of light incident on the light receiving element array 1 decreases from the center toward both ends of the array. Therefore, each of the light receiving elements 2
The signal output becomes non-uniform, resulting in a configuration 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 opening 4 of the cold shield 3, the shading phenomenon can be reduced. The problem was that the size of the device became large.

(d) Purpose of the Invention In view of the above-mentioned conventional drawbacks, the present invention improves the shape of the field-of-view determining opening of the cold shield with respect to the entire light-receiving element surface of the one-dimensionally arranged infrared light-receiving element array. It is an object of the present invention to provide a novel cooling type 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, the present invention provides a photoelectric conversion device equipped with a cold shield having a field-of-view determining opening in front of an infrared receiving element array, which defines the range of incident light. A plurality of light-shielding partition plates are placed in the opening of the cold shield in a direction perpendicular to the light-receiving surface of the light-receiving element array and perpendicular to the center line in the arrangement direction of the light-receiving element array, so that the partition plates are arranged in half on the center line. This is achieved by providing a cooled photoelectric conversion device characterized in that it is arranged in two rows at a predetermined interval so as to be shifted by a pitch.

(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 one embodiment of the structure of the opening of the cold shield in the cooled photoelectric conversion device according to the present invention.

As shown in FIG. 2, in the present invention, a cold sensor is arranged one-dimensionally on a cooling head (not shown) and faces all the light-receiving elements of the infrared light-receiving element array 1 at a predetermined height. For example, the shape of the field-of-view determining opening 4 of the shield 3 may be changed to
an X light-shielding partition plate 21 having a predetermined width perpendicular to the light-receiving surface of the light-receiving element array 1 and along the center line A in the arrangement direction of the light-receiving element array 1;
Similarly, a plurality of Y light shielding partition plates 22 having the same width as the X light shielding partition plate 21 and perpendicular to the light receiving surface and perpendicular to the X light shielding partition plate 21 are connected to the X light shielding plate 22 as shown in the figure. They are arranged in two rows at a predetermined interval, with the partition plate 21 at the center and shifted by half a pitch from both sides.

However, in this case, the predetermined interval section 23 formed by each Y light-shielding partition plate 22 does not need to correspond to each light receiving element 2 surface of the opposing light receiving element array 1. The field-of-field determining opening 4 of the shield 3 has a configuration in which Y light-shielding partition plates 22 are shifted by a half pitch from both sides with the X light-shielding partition plate 21 in the center, and the X light-shielding partition plate 21 and each Y
By appropriately selecting the width L of the light shielding partition plate 22, the distance D between the Y light shielding partition plates 22, the height H of each of the X and Y light shielding partition plates 21 and 22 with respect to the two surfaces of the light receiving element, etc., the above-mentioned It becomes possible to define the viewing angles on each light-receiving surface 24 of the light-receiving element array 1 extremely evenly. In particular, for example, a plurality of light-shielding partition plates perpendicular to each light-receiving surface of the light-receiving element array 1 and orthogonal to the arrangement direction of the light-receiving element array are provided in the field-of-view determining opening 4 of the cold shield 3. of,
Compared to a case where the light-shielding partition plates are simply arranged in parallel at a predetermined interval, the fluctuation of shedding having a period equal to the parallel pitch of the light-shielding partition plates is reduced to about 1/2 or less.

Therefore, the shading phenomenon occurring 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 can be significantly reduced.

Note that the X light-shielding partition plate 21 is the Y light-shielding partition plate 22.
Although it was provided to maintain mechanical strength when installing, it is not necessary for the function.

(g) Effects of the Invention As is clear from the above description, according to the cooled photoelectric conversion device of the present invention, the cold shield is arranged to face all the light receiving element surfaces of the one-dimensionally arranged infrared light receiving element array. A plurality of light-shielding partition plates each having a shape perpendicular to the light-receiving surface of the light-receiving element array and orthogonal to the center line in the arrangement direction of the light-receiving element array are placed in the field-of-view determining opening of the light-receiving element array at a half-pitch on the center line. Since the two rows are arranged at a predetermined interval so as to be shifted from each other, it is possible to uniformly define the effective viewing angle on each light receiving element surface of the light receiving element array, thereby eliminating the conventional shading phenomenon. This has the advantage that it is significantly reduced.

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. 2 is a schematic perspective view showing an example of the structure of the opening of the cold shield in the cooled photoelectric conversion device according to the present invention. In the drawings, 1 is an infrared receiving element array; 2 is an infrared receiving element array;
2a 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 an X light-shielding partition plate, 22 is a Y light-shielding partition plate, 23 is a A predetermined interval part, 24 indicates each light receiving surface, and A indicates a center line.

Claims (1)

[Claims] 1. In a photoelectric conversion device equipped with a cold shield having an opening for determining the field of view that defines the range of incident light on the front surface of the infrared receiving element array 1,
A plurality of light-shielding partition plates 22 are installed in the opening of the cold shield 3 in a direction perpendicular to the light-receiving surface of the light-receiving element array 1 and perpendicular to the center line A in the arrangement direction of the light-receiving element array. A cooling type photoelectric conversion device characterized in that the device is arranged in two rows at a predetermined interval so as to be shifted by half a pitch on a center line.