JPS5979127A - Infrared-ray photoelectric converter - Google Patents

Abstract

PURPOSE:To simplify a structure and to omit an infrared ray condensing lense by reflecting the light made incident from an entrance of L-shaped hole of a cooling head by a concave mirror to receive it by an infrared-ray inspecting element provided at an exit. CONSTITUTION:Only the light of prescribed wavelength in the light made incident into an optical filter 7 provided at the entrance of L-shaped hole of a cooling head is transmitted selectively, reflected by the concave mirror 12 to be deflected to vertical direction, and is imaged on the infrared-ray inspecting element 1 provided at the exit. Since the mirror 12 is used, the structure is simplified and the infrared-ray condenser lens is unnecessary.

Description

[Detailed Description of the Invention] +8+ Technical Field of the Invention The present invention relates to an infrared photoelectric conversion device, and more specifically,
The infrared detecting element of the infrared photoelectric conversion device is of a back-illuminated type, and the light that has passed through the optical filter is diverted at right angles by a concave mirror provided in an L-shaped hole formed in the cooling head, and is condensed. The present invention relates to an infrared photoelectric conversion device having a simplified optical system that does not require a separate condensing lens by allowing the infrared rays to enter the light receiving surface of the infrared sensing element.

(bl) Prior Art and Problems The photoelectric conversion device is equipped with an infrared condenser lens and forms an infrared image of a target object on an infrared sensing element, similar to a normal visible light camera.Furthermore, the operation of the infrared sensing element The temperature needs to be cooled to a particularly low temperature using a refrigerant, and a complicated cooling structure is required for this purpose.These two points are major factors that hinder the soaring cost of the infrared photoelectric conversion device and the reduction in size and weight. There is.

Now, germanium (Ge) or silicon (Sl) is generally used as the material for the infrared condensing lens depending on the wavelength. The infrared condensing lens conventionally used is a very bright germanium (Ge) condensing lens with a diameter of about 50 mm, but it is extremely expensive because of the material it is made of.

Further, in some cases, for example, in a Schottky barrier type infrared sensing element, the light receiving surface of the element and the wiring surface for pixels, etc. are opposite to each other. Hereinafter, an infrared sensing element having such a light receiving surface and a wiring surface will be referred to as a back-illuminated infrared sensing element. In such a case, the assembly structure of the infrared photoelectric conversion device becomes quite complicated. If the cooling structure for the infrared sensing element is added to this, it becomes even larger and more complicated. This example is conceptually illustrated in the sectional view of FIG.

Taking the aforementioned Schottky barrier type Si infrared sensing element 1 as an example of a back-illuminated photoelectric conversion element, since the operating temperature of the infrared sensing element 1 is low, it is mounted in close contact with the element mounting block 2. After mounting, a relay ceramic 4 is further bonded and disposed on the element mounting block 2 with an adhesive.

The wiring surface of the photoelectric conversion element and the output terminal 6 provided on the surface of the relay ceramic 4 are connected by bonding with a thin gold wire 5. The thus formed intermediate assembly block is assembled in close contact with the cooling head 3. The cooling head 3 is actually housed in a heat insulating container (not shown), and is always kept at a low temperature by being cooled by a cooling device (not shown) while the infrared sensing element is in operation.

Next, an optical filter 7 having a light transmission characteristic corresponding to the wavelength of light to be incident on the infrared detecting element 1 is arranged on the support block 9 together with the cold shield 8. Since both the optical filter 7 and the cold shield 8 need to be cooled to a low temperature so that they do not emit unnecessary infrared rays, the support block 9 is made of thick copper having high thermal conductivity.

It is assembled in close contact with the cooling head 3.

The above assembly structure was necessarily introduced to satisfy the conditions for each assembly element, but especially the space S generated near the wiring surface of the infrared sensing element 1.
It is necessary to ensure that

The cooling head 3 and the optical filter 7 are the infrared detection element 1
The infrared imaging device is large in size, has a complicated structure, has a large number of parts, and has the disadvantage of increasing its cost.

On the other hand, the infrared condensing lens 10 is considered indispensable, and as mentioned above, it is bulky and expensive, so it would be desirable to omit it if possible.

There has been a demand for some kind of improvement measure to solve the above-mentioned problems.

(C1 Object of the Invention The present invention has been made in view of the above-mentioned points, and improves the optical system of the infrared imaging device so that the wiring surface of the infrared sensing element 1 can be disposed on the surface of the cooling head 3. The purpose is to simplify the structure of the device and omit an expensive infrared condensing lens.

(di) Structure of the Invention The object of the above invention is to provide an infrared photoelectric conversion device equipped with a back-illuminated infrared sensing element, which is cooled by a cooling device and maintained at a predetermined low temperature, and which is separated from the cooled end. A through the part.

A cooling head formed with an L-shaped hole having 82 openings, and a cooling head located at a corner of the L-shaped hole so as to divert the incident light from the opening A at right angles and condense the light. and a back-illuminated infrared sensing element whose light-receiving surface is disposed in the opening B of the cooling head so as to vertically receive the incident light that has propagated at right angles. easily achieved.

(el Embodiments of the Invention The embodiments of the invention room will be described below with reference to the drawings. FIG. 2 is a cross-sectional view conceptually showing an embodiment of the improved structure of the infrared imaging device based on the present invention. .

The difference between the conventional structure shown in FIG. 1 and the old and new structure according to the present invention shown in FIG. 2 lies in the optical path.

That is, in the conventional structure shown in FIG. 1, the infrared rays emitted from the target object are condensed by the infrared condensing lens 10 and then travel in a straight line, whereas the optical path is a straight line. In one embodiment of the new structure based on the present invention, the infrared rays from the target object do not pass through the infrared condensing lens 10 (i.e., they directly pass through the optical filter 7 and pass through the optical path M inside the cooling head 3). The concave mirror 12 provided on the slope of the corner of the 11-shaped hole 11 opened on the two sides A and B bends the light at right angles into an L shape and condenses the light. An image is formed on the infrared detecting element 1''2. That is, since the condensing effect of the concave mirror 12 is utilized, the infrared condensing lens 10 as described above is not required.

As shown in FIG. 2, the infrared detecting element 1 and the optical filter 7 are directly bonded to the cooling head 3 itself and are disposed in the openings A and B of the surfaces 3a and 3b, respectively, so that the infrared rays The detection element 1 and the optical filter 7 are cooled more strongly.

The conventional element mounting block 2 and support block 9 are no longer necessary, and the overall structure is simplified and made smaller and lighter.

An infrared detection element 1 is bonded to the surface 3a of the cooling head 3 with its light receiving surface covering the exit opening B of the L-shaped hole 11 of the cooling head 3, and a relay ceramic 4 is bonded and disposed in contact with this. It has been done.

The circuit on the wiring surface of the infrared sensing element 1 is connected to the output terminal 6 on the relay ceramic 4 using a thin gold wire 5 by bonding, as in the conventional case.

Since the above-mentioned wiring space is located outside the cooling head 3, there is no need to provide a special space inside the cooling head 3, so the cooling head 5 can be formed in a small size.

On the other hand, the optical filter 7 and the cold shield 8 are disposed at the inlet opening A of the cooling head 3 in the same manner as in the prior art.

Therefore, after the light incident on the optical filter 7 is selectively transmitted by the optical filter 7, only light of a predetermined wavelength is transmitted, and then enters the inside of the square-shaped hole 11, and enters the corner of the square-shaped hole 11 with respect to the optical axis. The light is bent at a right angle by a concave mirror 12 arranged at 45 degrees, and is incident on the light receiving surface of the infrared detection element 1 at a right angle to form an image. The following is the same as before.

(f+ Effects of the Invention) As is clear from the explanation in Section 2, if the improved structure of the infrared photoelectric conversion device according to the present invention is adopted, the device can be made even more compact, and the number of assembly steps and number of parts can be reduced. In particular, the expensive infrared condensing lens can be omitted, and the cooling of the infrared sensing element and optical filter becomes more efficient, and the overall structure becomes stronger, improving the quality of the infrared photoelectric conversion device. , it has the effect of reducing the cost.

[Brief explanation of drawings]

Regarding an infrared imaging device, Figure 1 shows the conventional structure. FIG. 2 is a cross-sectional view conceptually showing one embodiment of the structure based on the present invention. ■ is an infrared detection element, 2 is an element mounting block, 3 is a cooling head, and 4 is a relay ceramic. 5 is a thin gold wire, 6 is an output terminal, and 7 is an optical filter. 8 is a cold shield, 9 is a support block, 10 is a red (red) line condensing lens, 11 is a 5-shaped hole, and 12 is a concave mirror. Figure 1

Claims (1)

[Claims] An infrared photoelectric conversion device that operates at a predetermined low temperature and includes a back-illuminated infrared sensing element in which a light-receiving surface and a circuit wiring surface are located on opposite surfaces, the device being operated by a cooling device. A cooling head that is cooled and maintained at a predetermined low temperature, and that is formed with an L-shaped hole that penetrates through it in a part other than the cooled end and has two openings A and B, and from the opening A. a concave mirror located at a corner of the 17-shaped hole to divert and condense the incident light at right angles; It is characterized by comprising a back-illuminated infrared sensing element disposed with its light-receiving surface placed in the opening B of the throat so as to vertically receive the incident light traveling at right angles. Infrared photoelectric conversion device.