JPS6033071A - Beam type body detector - Google Patents

Abstract

PURPOSE:To perform three-dimensional detection through a simple optical system with high sensitivity by providing a light emitting and photodetecting element near the focus as a parabolic reflecting mirror and the circumferential surface of said mirror is opened outward by a specific angle on the basis of the focus of the center axis. CONSTITUTION:The light emitting and photodetecting element 5 is arranged at the focus F of the parabolic surface reflecting mirror 4, which is open outward by the angle theta to the center axis X on the basis of the focus F. Therefore, a light beam B' radiated by the light emitting element 5 to the mirror surface is in an umbrella shape. Thus, a space to be monitored is detected in three dimensions by the single light emitting and photodetecting element with high sensitivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in emitting beams and light receiving and projecting mirrors using reflecting mirrors.

Optical object detectors include those that emit a beam of light into the monitored space and detect changes in the reflected light, and those that detect infrared light emitted from a human body, etc. that has entered the monitored space. Conventionally, these detection methods include an interruption detection method of a linearly projected beam light or a conical light condensing method.

However, in the light blocking method, since the detection range is linear, the direction of penetration is limited, and if the light is focused in an elliptic cone shape, the light will be dispersed, resulting in a reduction in detection sensitivity. Ta. As a solution to these problems, a method has been proposed in which the light beam is shaped like an umbrella, but this method has problems such as a complicated structure and difficulty in focusing.

The present invention solves these drawbacks in the umbrella type system, and FIG. 1 shows the light distribution state when the detector of the present invention is installed. It consists of a light emitting/receiving path 2, and when a person, for example, passes through the light path 2 into an umbrella-shaped space 3, an alarm (not shown) issues an alarm.

Note that the monitoring space is not limited to the floor surface, and can be used to direct any object to be monitored, such as a wall surface.

Fig. 2 shows the optical system of the diameter detector of the present invention, in which a light-emitting or light-receiving element 5 is arranged at the focal point F of a parabolic reflector 4, and the parabolic reflector 4 is aligned with the central axis X. On the other hand, it opens outward by e with respect to the focal point F. Therefore, for example, the light beam B' emitted from the light emitting element 5 to the mirror surface is emitted as an umbrella-shaped beam of light.

FIG. 3 is a diagram showing the principle of this optical system, in which line A is a normal parabola and F indicates its focal point. When line A is a mirror surface, all light emitted from focal point F becomes parallel rays B.

The parabola A' is obtained by rotating the parabola A by θ around the focal point F, and the reflected light from the focal point 1' with this line A' as a mirror surface becomes a parallel ray shown as B'. therefore,
The parabolic reflecting mirror 4 shown in FIG. 2, in which a mirror surface having a parabolic surface such as 13' is arranged with the focal point J' as a reference, produces an umbrella-shaped beam of light.

FIGS. 4 and 5 show an embodiment in which the detector of the present invention employs a method in which a light beam is irradiated onto a monitored space and a change in the reflected light is detected to detect an object. In these embodiments, reflecting mirrors 4 and 4' are provided separately in the light emitting section and the light receiving section, respectively. In Fig. 4, two reflecting mirrors 4 and 4' are arranged in parallel at the same distance from the object to be monitored, and in Fig. 5, the light receiving part is formed by the light emitting part. Although these embodiments are provided in an umbrella-shaped space, the arrangement of the light emitting section and the light receiving section is not limited to these embodiments.

As described above, the optical object detector of the present invention has features such as being able to detect the monitored space three-dimensionally and with high sensitivity using a single light emitter and receiver, and requiring only a simple optical system. .

[Brief explanation of drawings]

Figure 1 is a diagram showing the light distribution state when the optical object detector of the present invention is installed at Δ, Figure 2 is the parabolic reflector used in the optical object detector of the present invention, and Figure 3 is FIG. 2 shows the principle of a reflecting mirror, and FIGS. 4 and 5 each show an embodiment of the optical object detector of the present invention. 1... Light beam type object detector, 2 Umbrella beam light, 3...
・Umbrella-shaped space, 4... Parabolic reflector, 5... Emitting/receiving element

Claims (1)

[Claims] In a light beam type object detector that forms an emitting beam and/or a light receiving field in an umbrella shape using a reflecting mirror and detects an object entering the umbrella-shaped space, the reflecting mirror includes a light emitting and/or light receiving element near a focal point. What is claimed is: 1. A light beam type object detector, characterized in that it uses a parabolic reflector whose peripheral surface is opened outward at a predetermined angle with respect to the focal point of the central axis.