JPH0511532Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to the structure of an optical switch whose light blocking element is a magnetic fluid displaced by a magnet.

Prior Art Many optical switches that utilize magnetic force have a simple structure, especially those that have a mechanism in which a magnetic shutter is placed in the optical path and the shutter is displaced by an external magnet to conduct or close the optical path. A switch is proposed. For example, the optical switch disclosed in Utility Model Application Publication No. 54-20158 is shown in FIG. 3, and an electromagnet 102 is provided in a housing 101. The excitation coil 104 is wound around one pole 103 and fixed to the housing 101 . 105 and 106 are terminals of the excitation coil 104. Further, the other pole of the electromagnet 102 serves as a movable piece 106, and the excitation coil 1
By energizing 04, it is attracted to one pole 103 and moves downward. The tip of this movable piece 106 is formed in the shape of a shutter 107, and when this shutter 107 moves downward by the action of the excitation coil 104, optical fibers 108 and 109 are fixed to the housing 101 at a position that blocks the path of light. has been done. The optical fibers 108 and 109 have their respective ends facing each other across a gap g, so that light entering from one optical fiber passes through the gap g and is transmitted to the other optical fiber. .

Problems with the Prior Art As shown in the prior art described above, this type of optical switch uses an elastic ferromagnetic material as a shutter to conduct and close the optical path. External vibrations intermittently block the optical path, causing malfunctions. In particular, when a disturbance is applied to the natural frequency of the shutter, the number of malfunctions described above increases, creating a problem when mounting the shutter on a moving body or the like.

Means for Solving the Problems The present invention has been made to solve the above-mentioned problems. In the conventional technology, the shutter for blocking the optical path was made by separating a plate-like body made of an elastic ferromagnetic material. Focusing on the fact that as a result of being supported in a suspended manner, the shutter is more susceptible to external vibrations due to the operating direction of the shutter, we designed the light guide to open and close the light by utilizing changes in the optical characteristics at the U-shaped bottom. This is what we do. That is, a ferrofluid movably sealed liquid-tightly is immersed or released in the bottom of the U-shaped light guide;
A light switch is constructed by either conducting an optical signal incident from one end of both ends of the letter-shaped light guide to the other end, or by refracting and attracting the magnetic fluid.

Embodiment FIGS. 1 and 2 are diagrams for explaining one embodiment of the present invention. In the figures, 1 is a cylindrical casing made of a non-magnetic material, and the upper end surface 11 of the casing 1 has a U An optical connector 2 in which both ends 31 of a letter-shaped light guide 3 are fixed is attached. A coil spring 8 having a diameter slightly smaller than the inner diameter of the housing 1 is inserted into the bottom 12 of the housing 1, and a cylindrical moving body 4 is placed on top of the coil spring 8.
is placed. The outer diameter of the movable body 4 is slightly smaller than the inner diameter of the housing 1, and it can move up and down within the housing 1. The movable body 4 is made of a non-magnetic material, and has a concave portion 42 bored in the center of an upper end surface 41. The recess is filled with a magnetic fluid 6, and the magnetic fluid 6 is attracted by the annular magnet 5 embedded in the movable body 4 so as to surround the recess 42. It does not flow out of the concave portion 42. Further, a driven magnet 7 magnetized in the vertical direction is embedded in the movable body 4 at the bottom of the concave portion 42, and the driven magnet 7 is movably disposed in the vertical direction close to the bottom of the housing 4. It is magnetically coupled to the main drive magnet 9 which is magnetized.

Next, to describe the operation of the optical switch of the present invention, first, as shown in FIG.
When the distance G between the body 4 and the housing 4 is large and the magnetic force is small, the repulsive force of the coil spring 8 is stronger than this magnetic force, and the movable body 4 is in the middle position in the housing 1, and the bottom 32 of the U-shaped light guide 3 is It is immersed in magnetic fluid 6. A magnetic fluid is a black fluid that absorbs light in a suspension state in which fine magnetic particles are surface-treated and dispersed in kerosene, etc., which has a higher refractive index than air. As a result, an optical signal incident on the optical connector 2 in the P direction from a light source (not shown) is absorbed within the magnetic fluid 6 and does not proceed in the P' direction. Next, as shown in FIG. 2, when the main magnet 9 approaches the housing and G'≪G, the driven magnet 7 is attracted by the main magnet 9, and along with this, the moving body 4, the magnetic fluid 6 also moves downward, and U
The shaped light guide 3 is spaced apart from the magnetic fluid. Therefore, the incident optical signal is repeatedly reflected on the entire surface of the U-shaped light guide 3 as indicated by the arrow P, while the optical signal P' is transmitted. As mentioned above, in the optical switch of the present invention, the main driving magnet 9 is placed close to the housing 1 so that the magnet 9 is empty.
By separating them, the optical signal P is interrupted. In the figure, the driven magnet 7 is buried in the movable body 4 so as to be located at the bottom of the recessed part, but it does not necessarily have to be in this position, and depending on the magnitude of the magnetic force, the driven magnet 7 may be buried in the movable body 4. Only the annular magnet 5 may be used except for the annular magnet 5. Further, the main magnet 9 may be a solenoid such as an electromagnet instead of a permanent magnet, and the important point is that the movable body 4 can move against the spring force of the coil spring 8.

Effects As mentioned above, according to the optical switch of the present invention,
Since both ends of the U-shaped light guide 3, which is a component of the optical switch, are fixed, it has high rigidity and is stable against external vibrations. Moreover, the light switch is U
Since the bottom of the shaped light guide is immersed in and separated from the magnetic fluid 6, which absorbs a large amount of light, light is absorbed by the entire surface and is reflected, so that there is no malfunction caused by vibration, and stable switching is performed. Furthermore, when the bottom of the light guide is immersed in the magnetic fluid 6, the magnetic fluid acts as a damper, making it possible to provide a stable optical switch that is not available in the prior art.

[Brief explanation of the drawing]

1 and 2 are structural explanatory diagrams of the optical switch of the present invention. FIG. 1 is a diagram showing the operation when the switch is open, FIG. 2 is a diagram showing the operation when the switch is closed, and FIG. 3 is a diagram for explaining the conventional technology. It is a diagram. 1... Housing, 2... Optical connector, 3... U-shaped light guide, 4... Moving body, 5... Annular magnet, 6...
magnetic fluid, 7... driven magnet, 8... coil spring,
9... Active magnet.

Claims (1)

[Scope of utility model registration request] A cylindrical casing made of non-magnetic material, an optical connector disposed on the upper end surface of the casing, a U-shaped light guide whose both ends are connected to the optical connector, and a recess capable of accommodating the U-shaped light guide. a movable body that is movable in the axial direction within the housing; and a movable body that is held by the magnetic force of the annular magnet and is housed in the recess. a magnetic fluid; and a coil spring stretched between the bottom of the housing and the bottom of the movable body so that the curved portion of the U-shaped light guide is immersed in the magnetic fluid;
When the active magnet, which is disposed outside the bottom of the housing so as to be movable in the axial direction of the housing and is magnetically coupled to the driven magnet, approaches the bottom of the housing, the U-shaped light guide conducts light, and when the active magnet separates, the An optical switch characterized by a U-shaped light guide that blocks light.