JPH01217221A - Infrared sensor - Google Patents

Abstract

PURPOSE:To detect infrared rays incident at a wide view angle without a bland band width, by arranging an optical part having a function of a Fresnel type lens and a function of a mirror in front of a detector. CONSTITUTION:An infrared sensor 18 is arranged at the top of the outer surface of a cone 10 and small mirror pieces 12, 14 and 16 are arranged in the perimeter thereof. A parabolic optical part 20 is mounted on the front of the infrared sensor 18. The internal surface of the optical part 20 has an incomplete reflecting function while a function of letting infrared rays pierce it inside. Projection beams 22, 24 and 26 are reflected on small mirror pieces 12, 14 and 16 and reflected on the internal surface thereof 20 to be focused on the sensor 18. Infrared rays 28 and 30 from the back of the optical part 20 are focused on the sensor 18 piercing the optical part 20. Thus, a sensor is manufactured having a wide view angle without a bland band width.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an infrared sensor having a wide field of view.

(b) Conventional Technology Many studies and inventions have been made regarding broadband infrared sensors, but one of the most outstanding ones is the United States Patent
tent) number 4,271.360.

However, the above-mentioned patent has a configuration in which an inverted cone-shaped optical component 10 with a small mirror piece installed on the surface and a parabola having a mirror function on the inside face each other. Because the parabola was positioned in front of the image, a serious defect occurred in that the background area could not be detected.

As a result of various researches to eliminate this blind zone, the present invention has been provided.

(c) Problems to be Solved by the Invention In order to eliminate the blind band in front of the detector 10, in the present invention, infrared energy is incompletely reflected on the inner surface of the parabola 20 and partially penetrated. By forming a thin film of
2, 24, and 26 are reflected by the small mirror pieces 12, 14, and 16 on the surface of the inverted conical optical device 10, and then reflected by the incomplete reflecting mirror on the inner surface of the parabola 20 to reach the detector. .

Regarding the viewing angle up to this point, it has roughly the same function as the conventional one.

(d) Means for Solving the Problem Therefore, the feature of the present invention is that by using a parabola made of a polymeric material that allows infrared energy to pass through, the infrared energy coming from the blind band in the background area is 28.30.
penetrates and reaches the detector 18, and the blind zone disappears as shown in the side view in FIG. 4 and in the front view in FIG. 5.

(E) Effect: While a thin film is provided on the inner surface of the parabola 20 made of an infrared-transmissive material such as polymeric sugar to give it an incompletely reflective mirror function, a part of the parabola or The part beyond that has the function of a split lens.

(F) Embodiment This example has a viewing angle of 360°, and a 180° type is shown in longitudinal sectional views in FIGS. 3 and 6.

That is, the detector 1 is placed in the center as shown in the front view in FIG.
8, and an inverted cone-shaped optical component 10 with small mirror pieces 12, 14 and 16 around it, and has an incomplete reflective function on its inner surface as shown in the side view in FIG. The sensor has a configuration as shown in Fig. 3, which has a field of view covering the entire circumference of 360'', in which parabolic optical parts 20 with a penetrating lens function are placed opposite each other, and the field of view is shown in Figs. Shown in figure and front view.

This type of sensor is suitable for ceiling installation.

On the other hand, the wall-mounted type sensor shown in FIG. 6 in longitudinal section is suitable for a viewing angle of 180 degrees, and has a detector 40 arranged on the circuit board 38 and a semi-conical type sensor with a small mirror piece. Optical component 34 (In the figure, it is integrated with a part of the case)
A half-ball (b) that has both reflective and lens functions.
The base 38 and the optical component are fixed with mounting screws 42.

Infrared energy 22 that is not blocked at all by the half-pole 36 is reflected by the half-cone optic 34 and then reflected again inside the half-ball optic 36 to reach the detector.

On the other hand, in the conventional method, the infrared energy of 3° on one side of the half-ball optical component 36, which could not be detected, is focused by a group of Fresnel-type or other condensing lenses, as shown in an enlarged view in the figure. It reaches the detector 40.

In this process, the infrared energy that passes through the half-ball shaped optical component or the aforementioned parabolic optical component is attenuated to some extent, but generally the back surface of these optical components is Since the distance between the radiator and the detector is close compared to other objects in the field of view, sufficient energy intensity can be obtained, so in practical use, the effect of attenuation will hardly be a problem.

(G) Effects of the Invention According to the present invention, it is possible to manufacture an infrared sensor having a wide viewing angle without a blind band, and is expected to have industrial value.

[Brief explanation of the drawing]

FIG. 1 shows a front view of an inverted conical optical component 10 having an infrared detector 18 in the center and small mirror pieces 12, 14 and 16 around it. FIG. 2 is a side view of an optical component 20 having both a reflection function and a lens function according to the present invention, which is a side view of the optical component shown in FIG. FIG. 3 is a vertical sectional view showing the structure of an infrared sensor that combines these optical components. FIG. 4 shows the field of view of the infrared sensor of the present invention in a longitudinal cross-sectional view. FIG. 5 shows the field of view of the invention in front view. However, the field of view corresponding to 28 and 30 in FIG. 4 could not be depicted because the center of the drawing was overcrowded. FIG. 6 shows a longitudinal cross-sectional view of a wall-mounted infrared sensor.

Claims (1)

[Claims] An infrared sensor characterized in that an optical component 20 having both a Fresnel lens function and a mirror function is provided on the front surface of the detector.