JP2001343620A - Door opening and closing detection sensor using faraday element type optical switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a door opening and closing detection sensor using a Faraday element type optical switch capable of detecting not only the opening and closing of a door to be monitored but the disconnection of an optical fiber as well and having high reliability. SOLUTION: This sensor is so constituted that a magnetic section parts from the Faraday element type optical switch when the door to be monitored is held closed and that the magnet section approaches the optical switch when the door is held open.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a door open / close detection sensor using a Faraday element type optical switch. More specifically, the present invention relates to a door open / close detection sensor using a Faraday element type optical switch that recognizes the open / closed state of a monitored door based on the presence or absence of a return light pulse using a Faraday element type optical switch. .

[0002]

2. Description of the Related Art There are many types of sensors for detecting the opening and closing of a door, including those using a mechanical switch. As a recently developed door opening / closing detection sensor, there is a door opening / closing detection sensor using a Faraday element type optical switch.

FIG. 3 is a configuration diagram of a door open / close detection sensor using a conventional Faraday element type optical switch. 11 is a magnet unit, 12 is a Faraday element type optical switch, 13 is an optical fiber, and 14 is a door. A door open / close detection sensor using a conventional Faraday element type optical switch includes a magnet unit 11 attached to a door 14, a Faraday element type optical switch 12 operated by the magnet unit 11, and a signal detector (shown in FIG. ), And an optical fiber 13 that propagates an optical pulse emitted from the light source.

[0004] When the door 14 is closed, the magnet unit 11 is arranged to be close to the Faraday element type optical switch 12, and when the door 14 is opened, the magnet unit 11 is separated from the Faraday element type optical switch 12. I have.

The Faraday element type optical switch 12 comprises a lens, a birefringent plate, a Faraday element, and a total reflection plate. When the magnet unit 11 is not approaching, the optical pulse emitted from the light source of the signal detector enters the Faraday element type optical switch 12 after propagating through the optical fiber 13 and passes through the lens, the birefringent plate, and the Faraday element. Reflected by the total reflection plate, and returns to the signal detector through the same optical path.

When the magnet unit 11 approaches the Faraday element type optical switch 12, an optical pulse emitted from the light source of the signal detector enters the Faraday element type optical switch 12 after propagating through the optical fiber 13 and is subjected to lens and multiple light. The light passes through the refraction plate and the Faraday element and is reflected by the total reflection plate.
Due to the magnetic field, the polarization plane of the light pulse rotates at the Faraday element, and the light path when the light pulse comes and returns is shifted, so that the light pulse cannot return to the signal detector.

Therefore, when the door 14 to be monitored is opened, the magnet 11 moves away from the Faraday element type optical switch 12, so that the polarization plane of the light pulse does not rotate in the Faraday element, and the light pulse is detected as a signal. Come back to the vessel. When the door 14 to be monitored is closed, the polarization of the optical pulse is rotated at the Faraday element, and the optical pulse returns to the signal detector because the magnet unit 11 is close to the Faraday element type optical switch 12. Absent.

As described above, the conventional door open / close detection sensor using the Faraday element type optical switch is configured to detect the open / close of the door to be monitored based on whether or not a light pulse returns. When the light pulse returns, it can be recognized that the door is open, and when the light pulse does not return, the door is closed.

[0009]

A door open / close detection sensor using a conventional Faraday element type optical switch has the following problems.

The door to be monitored is normally in a closed state, and the door open / close detection sensor using the above-mentioned Faraday element type optical switch does not normally return a light pulse. Therefore, if the optical fiber connecting the signal detector and the Faraday element type optical switch is cut off for some reason, it cannot be determined that the optical fiber is normal, so that the user does not notice the cut of the optical fiber. In such a case, even if the monitored door is opened by an intruder, it cannot be detected,
It is impossible to fulfill the original purpose of monitoring.

Accordingly, an object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to detect the opening and closing of a door using a highly reliable Faraday element type optical switch capable of detecting not only the opening and closing of a monitored door but also the disconnection of an optical fiber. It is to provide a sensor.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, when a monitored door is closed, a magnet portion moves away from the Faraday element type optical switch, and when the monitored door is opened, the magnet is closed. The unit is configured to approach the Faraday element type optical switch.

[0013] The magnet unit is configured to be close to the Faraday element type optical switch by a spring.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1A and 1B show an embodiment of a door open / close detection sensor using a Faraday element type optical switch according to the present invention. FIG. 1A is an external view, and FIG. FIG. 1 is a magnet part, 2 is a Faraday element type optical switch, 3 is an optical fiber, 4 is a rod, 5 is a spring, 6
Denotes a housing, and 7 denotes a lid.

The door open / close detection sensor using the Faraday element type optical switch according to the present invention comprises a rod 4
And the magnet part 1 attached to the tip of the rod 4
And a Faraday element type optical switch 2 operated by the magnet unit 1, and a spring 5. Spring 5, magnet unit 1, Faraday element type optical switch 2, and optical fiber 3
Are housed in a housing 6 and covered with a lid 7.

The internal configuration and operation principle of the Faraday element type optical switch 2 are the same as those of the Faraday element type optical switch described in the prior art.

FIGS. 2A and 2B show the operation of the door open / close detection sensor using the Faraday element type optical switch shown in FIG. 1, wherein FIG. 2A is an explanatory view when the door is closed, and FIG. FIG. 7 is an explanatory diagram in the case where is opened. 8 is a door.

FIG. 2 with the door 8 to be monitored closed
2A, the rod 4 is pushed in by the door 8, and the magnet unit 1 moves away from the Faraday element type optical switch 2. FIG. As a result, the rotation of the polarization plane of the incident light pulse at the Faraday element inside the Faraday element type optical switch 2 does not occur, and the light pulse returns to the signal detector.

FIG. 2 with the door 8 to be monitored open
In (b), the rod 4 extends by the spring 5 and the magnet part 1 approaches the Faraday element type optical switch 2. As a result, the polarization of the incident light pulse is rotated by the magnetic field of the magnet unit 1 in the Faraday element inside the Faraday element type optical switch 2, and the light pulse does not return to the signal detector.

Therefore, according to the door open / close detection sensor using the Faraday element type optical switch of the present invention, the light pulse returns when the monitored door is closed (normal state), and the monitored door is opened. At this time, the optical pulse is not returned.

If the optical fiber 3 breaks, the light pulse will not return to the signal detector, and the monitoring system will display an indication that the door to be monitored is open. At this time, by confirming that the door to be monitored is actually closed, it is possible to recognize that the optical fiber is disconnected.

The door open / close detection sensor using the Faraday element type optical switch according to the present invention can be applied not only to doors but also to monitoring of open / close of gratings, manhole covers, and the like. Although a spring is used as a means for extending the rod when the door to be monitored is opened, a similar mechanism can be made by using an elastic component other than the spring, for example, an air damper.

[0024]

According to the door opening / closing detection sensor using the Faraday element type optical switch of the present invention, when the monitored door is closed, the magnet moves away from the Faraday element type optical switch and the monitored object door is opened. Door opening / closing detection using a highly reliable Faraday element type optical switch that can detect not only the opening and closing of the monitored door but also the disconnection of the optical fiber because the magnet portion is configured to sometimes approach the Faraday element type optical switch. A sensor can be provided.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a door open / close detection sensor using a Faraday element type optical switch of the present invention,
(A) is an external view, (b) is an internal configuration diagram with a lid removed.

FIGS. 2A and 2B show the operation of a door open / close detection sensor using the Faraday element type optical switch shown in FIGS.
FIG. 4 is an explanatory diagram when the door is closed, and FIG. 4B is an explanatory diagram when the door is opened.

FIG. 3 is a configuration diagram of a door open / close detection sensor using a conventional Faraday element type optical switch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnet part 2 Faraday element type optical switch 3 Optical fiber 4 Rod 5 Spring 6 Housing 7 Cover part 8 Door 11 Magnet part 12 Faraday element type optical switch 13 Optical fiber 14 Door

Claims (2)

[Claims] When the door to be monitored is closed, the magnet moves away from the Faraday element type optical switch, and when the door to be monitored is open, the magnet approaches the Faraday element optical switch. A door open / close detection sensor using a Faraday element type optical switch, characterized by comprising: 2. A door open / close detection sensor using a Faraday element type optical switch according to claim 1, wherein the magnet portion is configured to be close to the Faraday element type optical switch by a spring.