JPS60200133A - Detecting device of infrared rays - Google Patents

Abstract

PURPOSE:To improve the efficiency of condensation of infrared rays of an infrared ray detecting device, by disposing a small-sized subordinate concave mirror in the vicinity of the focus of a main concave mirror with an infrared ray detector disposed in the central part, in such a manner that the reflecting surface thereof is opposite to that of the main concave mirror. CONSTITUTION:A condensing means is formed of a main concave mirror 1a with an infrared ray detector 2 disposed in the central part and a small-sized subordinate concave mirror 1b disposed in the vicinity of the focus of the main concave mirror 1a in such a manner that the reflecting surface thereo is opposite to the reflecting surface of the main concave mirror 1a, and infrared rays condensed by the two concave mirrors 1a and 1b are made incident in the infrared ray detector 2. The focal lengths of the two concave mirrors 1a and 1b are f1 and f2 respectively, and the focuses thereof are made to coincide with each other while the subodinate concave mirror 1b employed has substantially the same width with that of a detection window 2a of the infrared ray detector 2. Thus, a condensed beam formed of substantially parallel lights in the same width with that of the detection window 2a is made incident in the infrared ray detector 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field 1] The present invention relates to an infrared detection device that detects infrared rays emitted from a human body or the like.

[Background Art 1 Conventionally, this type of infrared detection device has a
Infrared rays emitted from a human body or the like within a detection area are collected by a condensing means consisting of a concave mirror 1 and detected by an infrared detector 2, and a human body detection signal is output based on a change in the output of the infrared detector 2. The condensing means was formed using one concave mirror 1, and an infrared detector 2 was disposed near the focal point of the condensing means, but the shadow of the infrared detector 2 disposed near the focal point of the concave mirror 1 This has caused a problem in that the efficiency of collecting infrared rays by the concave mirror 1 deteriorates. In particular, when placing a printed circuit board equipped with an amplifier circuit, a signal processing circuit, etc. near the infrared detector 2 in order to reduce the influence of foreign noise, the shadow becomes thicker and the effective aperture area of the concave mirror 1 becomes smaller. Therefore, there was a problem that the efficiency of collecting infrared rays deteriorated significantly.

[Object of the Invention 1] The present invention has been made in view of the above points, and one object thereof is to provide an infrared detection device with good infrared light collection efficiency.

[Disclosure of the Invention 1 (Embodiment 1) Fig. 2 shows an embodiment of the present invention, in which a main concave mirror 1a with an infrared detector 2 disposed in the center and a main concave surface $7 are shown.
A small biconcave mirror 11) disposed near the focal point of the main concave mirror 1a and whose reflecting surface faces the reflecting surface of the main concave mirror 1a forms a condensing means, and the biconcave mirrors 1a, 1. The infrared rays collected at point b are made to enter the infrared detector 2.

In the embodiment, a biconcave mirror 11 with a J corner that is approximately the same width as the detection window 2a of the infrared detector 2 is used.
A condensed beam consisting of approximately the same width as the width of the beam is made incident on the infrared detector 2. This infrared detector 2 is made of an organic pyroelectric material (PVF2) or an inorganic pyroelectric material (PVF2).
It is formed with an itafocal x-type infrared i sensor using LiNbO3, LiTa03). In the figure, fl, +2 is the focal length of the biconcave mirrors 1a, 1b, and the biconcave mirrors 1a, 1,
+1's focus is on matching. Here, a double concave mirror 1a
, 11, a spherical surface, an aspherical surface, a parabolic surface, etc. can be considered as the offending surface. Also, the focal length of the main concave mirror 1a is fl
is set to 30 to 40 nun due to constraints such as the overall shape and the detection sensitivity of the infrared detector 2.

(Embodiment 2) FIG. 3 shows another embodiment, in which the configuration is the same as in Embodiment 1, and the condensing point by the biconcave mirrors 1a and 1b is the sensing element -T- of the infrared detector 2. It should be in the cn position. Therefore, the focused infrared light is reliably incident on the infrared detector 2 and detected. Note that the shapes of the double concave mirrors 1a and 1b are not limited to the embodiments.

(Effects of the Invention) As described above, the present invention focuses infrared rays from a detection area using a condensing means, detects them with an infrared detector, and outputs a detection signal based on a change in the output of the infrared detector. The infrared rays detection device consists of a main concave mirror with an infrared detector arranged in the center, and a small biconcave mirror arranged near the focal point of the main concave mirror with its reflecting surface facing the reflecting surface of the main concave mirror. The infrared rays that form the optical means and are focused by a biconcave mirror are incident on the infrared detector, and since only the shadow of the small biconcave mirror appears on the main concave mirror, if the infrared detector is large Even if it is, the effective aperture area of the condensing means can be made large.This effect is due to the fact that the amplifier circuit, signal processing circuit, etc. of the infrared detector can be This is particularly effective when placed nearby.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional example, FIG. 2 is a schematic diagram of an embodiment of the present invention, and FIG. 3 is a schematic diagram of another embodiment. 1a is a main concave mirror, 1b is a biconcave mirror, and 2 is an infrared detector. Agent Patent Attorney Ishi 1) Chief 7 Figure 1 Figure 2

Claims (1)

[Claims] (1) In an infrared detection device that collects infrared rays from a detection area using a condenser, detects the collected infrared rays with an infrared detector, and outputs a detection signal based on a change in the output of the infrared detector,
A condensing means is formed by a main concave mirror with an infrared detector arranged in the center and a small biconcave mirror arranged near the focal point of the main concave mirror and whose reflecting surface faces the reflecting surface of the main concave mirror. An infrared detection device that makes infrared light collected by an infrared light beam enter an infrared detector.