JPH04329677A - Infrared ray detecting element - Google Patents

Abstract

PURPOSE:To prevent deterioration of space resolution of an infrared ray detecting element. CONSTITUTION:An upward oblique surface 16 is formed on an upper surface of an edge of an electrode 13 surrounding a photodetector 12, and an infrared ray 15 incident from an optical system 11 on the electrode 13 is largely deflected from the system 11 and the photodetector 12 to prevent it from being again incident on the photodetector 12.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of an infrared detection element.

0002

[Prior Art] An infrared detector focuses infrared rays emitted from an object onto an infrared detecting element using an optical system consisting of a filter, lens, etc., and processes the electrical signal generated through photoelectric conversion within the infrared detecting element. It detects infrared rays. Among infrared detection elements, a conventional photoconductive type element will be explained using FIG. 3. The infrared detection element includes a light receiving section 32 that senses infrared rays, and an electrode section 33 that transmits a photoelectrically converted electric signal to the outside. It is composed of. Since the electrode part 33 is generally formed by a vapor deposition method, its surface has a mirror surface state and reflects almost 100% of infrared rays.

0003

As shown in FIG. 3, there are two types of paths through which infrared rays emitted from an object enter the light receiving section 32. First, as shown in 34, the light is collected by an optical system 31 consisting of a filter, a lens, etc., and is directly sent to the light receiving section 32.
The second path, as shown in 35, is a path through which the light is similarly focused by the optical system 31 and is transmitted to the electrode section 3 near the light receiving section 32.
3, is almost 100% reflected by the electrode section 33, returns to the optical system 31, is partially reflected by the optical system 31, and enters the light receiving section 32. The spatial resolution of the infrared detecting element is determined by the size of the light receiving part 32 of the infrared detecting element, considering only the infrared light 34 that directly enters the light receiving part 32 from the optical system 31.
If there is stray light 36 that is reflected by the electrode section 33 near the light receiving section 33 and the optical system 31 and enters the light receiving section 32 again, the spatial resolution effectively becomes a size that includes the electrode section 33 near the light receiving section 32. . The area of the electrode section 33 that enters the light receiving section 32 as stray light 36 varies depending on the configuration of the optical system 31, the distance between the optical system 31 and the infrared detection element, etc., but this deterioration of spatial resolution is caused by the area of the light receiving section 32. The smaller the value, the more noticeable it becomes.

An object of the present invention is to provide an infrared detection element that eliminates the generation of stray light.

[0005]

[Means for Solving the Problems] In order to achieve the above object, an infrared detection element according to the present invention includes a light receiving section,
An infrared detection element having an electrode part, the light receiving part is
It senses infrared rays, and the electrode part transmits the photoelectrically converted electric signal to the outside.It is formed by vapor deposition surrounding the light receiving part, and the upper surface of the electrode part in contact with the light receiving part is , which has an inclined surface in an upwardly inclined direction.

[0006]

[Operation] Infrared rays that enter near the edge of the electrode section are reflected by the inclined surface of the electrode section and deviate far beyond the optical system, so that they do not enter the light receiving section again.

[0007]

[Embodiments] Examples of the present invention will be explained below with reference to the drawings. In FIG. 1, the infrared detection element according to the present invention has a light receiving section 12 that senses infrared rays and an electrode section 13 that transmits a photoelectrically converted electrical signal to the outside. The opening edge is formed into an inclined surface 16 that slopes upward over a certain range.

In the embodiment, the edge of the electrode section 13 rises upward apart from the light receiving section 12, an opening is formed between the electrode sections 13, and the light receiving section 12 is formed within the opening. Note that the opening end surface of the electrode portion 13 is at least a vertical surface, and is set at an angle such that no light is received from above.

In the figure, infrared rays emitted from an object are collected by an optical system 11 consisting of a filter, a lens, etc., and are incident on a light receiving section 12 and an electrode section 13. Therefore, in addition to the infrared rays 14 directly incident on the light receiving section 12, there is also the infrared 15 incident on the electrode section 13 near the light receiving section, as in the conventional case. The infrared rays 15 are reflected on the inclined surface 16 of the electrode section 13 and are largely deviated and emitted in the direction opposite to the light receiving section 12.The infrared rays 15 reflected on the inclined surface 16 are then directly directed to the light receiving section 12 again. Alternatively, the spatial resolution can be accurately determined by the size of the aperture of the electrode section 13 because the light does not return to the optical system 11 and therefore is not re-reflected by the optical system 11 and enters the light receiving section 12. .

The infrared detecting element according to the present invention is shown in FIG.
Obtained by the manufacturing steps a) to (d).

(a) A first resist pattern 21 having an inclined side surface is formed on a crystal 22 of a substrate by adjusting exposure and development times. (b) After forming the first resist pattern 21, an electrode film is formed on the entire surface by vapor deposition, and then a second resist pattern 21 is formed so that only the electrode film 23 on the upper surface of the first resist pattern 21 is exposed.
A resist pattern 24 is formed. (c) Only the portion 25 not covered by the second resist pattern 24 is etched by ion milling. (d) When the first resist pattern 21 and the second resist pattern 24 are removed, the electrode section 13 having the inclined surface 16 near the portion in contact with the light receiving section 12 is obtained as shown in the figure.

0012

As described above, according to the present invention, infrared rays incident on the electrode portion are not reflected again and incident on the light receiving portion, and there is an effect that deterioration of spatial resolution can be prevented.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a manufacturing process of an infrared detection element.

FIG. 3 is a diagram showing a conventional example.

[Explanation of symbols]

12 Electrode part 13 Light receiving part 16 Slope surface

Claims (1)

[Claims] [Claim 1] An infrared detection element having a light receiving part and an electrode part, the light receiving part is for sensing infrared rays, and the electrode part is for transmitting a photoelectrically converted electric signal to the outside. An infrared detecting element, characterized in that it is formed by a vapor deposition method surrounding a light-receiving section, and has an upwardly inclined surface on the upper surface of the electrode section in contact with the light-receiving section.