JPS631563B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical path changing device constituting an optical application circuit.

Optical path changers used for communication, measurement control, etc. using optical fibers include lenses, mirrors, prisms, and recently, optical waveguides using optical integrated circuit technology. Among these, many of those that have been put into practical use for changing the optical path use lenses, mirrors, prisms, etc. As a typical conventional example, a schematic structural diagram of a prism movable optical path changing device (optical switch) is shown in FIG. 1, and a principle diagram is shown in FIG. 2. Regarding this method, for example, OQE-78-105
Or, Journal of the Institute of Electronics and Communication Engineers Vol. J63-C No.
1 Published in JANUARY 1980 P.16-P.23, etc. The operating principle will be explained. Prism 1a in FIG. 1 has a rhombic shape, and is fixed to movable housing 1b with adhesive or the like. A permanent magnet 1c is mounted inside the movable housing 1b, and magnetic pole pieces 1d of soft magnetic material are attached to both end faces of the permanent magnet.
1e are joined with adhesive to form the movable part 1. Fixed magnetic poles 2 made of soft magnetic material are located on the left and right sides of this movable part 1.
a and 2b are arranged and wound around wire rings 3a and 3b to form the magnetic poles of an electromagnet, and the positions thereof are fixed by non-magnetic magnetic pole holders 4a and 4b fixed to the substrate 6. By applying a positive or negative voltage to the electromagnet wire rings 3a, 3b from the drive current control circuit 7 and switching the current between positive and reverse, the movable part 1 moves left and right in the gap between the fixed magnetic poles 2a, 2b of the electromagnet. exercise. As a result of this operation, when the light beam 10 from a light emitting source (not shown) is in the state shown in FIG. 1, that is, when the movable part 1 is located on the fixed magnetic pole 2b side, the light beam 10 from the light emitting source (not shown) is in the state shown in detail in FIG. 7. As shown, the light beam 10 enters the prism 1a, is totally reflected inside, changes its optical path, and becomes the optical path of 10a. On the other hand, the movable part 1
When is located on the fixed magnetic pole 2a side, the light ray 10 does not enter the prism 1a and goes straight as it is.
This becomes the optical path of 0b. In other words, the optical path can be changed by electrical signals. In addition to the rhombic prism, a lens or mirror can be used as the optical path changer, and in this case as well, the optical path can be changed by refracting or reflecting the incident light, as stated in the Journal of the Institute of Electronics and Communication Engineers. It is publicly known as specifically described in . By using a permanent magnet in the movable part, even if the drive current is stopped after the movement operation, the attractive force of the permanent magnet will keep one fixed magnetic pole surface (2
a, 2b) and has a self-retaining effect that allows it to maintain its position. Here, especially when setting the optical path to 10a, the angle and positioning of the entrance surface of the rhombic prism 1a with respect to the incident light beam 10 are important. It is necessary to move part 1 in parallel while suppressing its rotational movement as much as possible. Therefore, a method is adopted in which a concave groove is provided in the contact surface of the movable part holder 5 (non-magnetic material) with the movable part 1 and the movable part holder 5 (non-magnetic material) is slid in this groove.

However, the conventional method described above has the following problems.

The holding force of the movable part after the drive current is turned off depends on the total magnetic flux of the permanent magnet and the magnetic pole area, and since the position is held only by the attraction force with the magnetic pole surface of one electromagnet, it is necessary to reduce the impact and vibration when trying to reduce the size and weight. become less resistant to

Since the soft magnetic body part (yoke) forming the magnetic circuit is not closed, the magnetic resistance is large, and therefore the power consumed to obtain the desired magnetic flux is large. This drive current can be applied in the form of positive and negative pulses, but if the switching operation is performed continuously, the temperature rise of the entire optical switch cannot be ignored, and this becomes a factor in fluctuations in optical insertion loss.

The optical path switching time is correlated with the drive current, and if the current value is constant, the magnetic resistance in the magnetic circuit,
Switching time increases due to mechanical friction.

The present invention has been made in order to improve the above-mentioned drawbacks, and its purpose is to provide a highly reliable optical path changing device that is resistant to vibration and shock, has reliable switching operation, quickness, reproducibility, and long life. It is in.

This invention improves vibration and shock resistance by integrating the yoke part that forms the electromagnet, providing three magnetic poles, and sliding a movable part that includes a permanent magnet with a prism etc. mounted on the central magnetic pole surface. The optical switching time and power consumption are reduced.

Next, one embodiment of this invention will be described. FIG. 3 shows a schematic structural diagram, and FIG. 4 shows a principle diagram. The operating principle and structure is that a movable housing 1b containing a permanent magnet (for example, an Sm-Co magnet, the magnetization direction is the sliding direction) 1c and magnetic poles 1d and 1e is connected to an electromagnet center magnetic pole (lower,
The yoke 8a, 8b and the electromagnet magnetic pole part 2
A three-magnetic pole structure is adopted in which the magnetic flux returns to the central magnetic pole portion 9 via a and 2b. A known optical path changer is mounted on the movable housing 1b. This embodiment shows, as an example, a case in which a rhombic prism 1a is installed as in the case of FIG. When energized as shown in FIG. 3, the movable portion 1 is attracted to the electromagnet magnetic pole 2b side. When the driving current control circuit 7 reverses the current direction, a repulsive electromagnetic force is generated between the electromagnet magnetic pole 2b and the magnetic pole 1e, and an attractive electromagnetic force is generated between the electromagnet magnetic pole 2a and the magnetic pole 1d, and the movable part 1 moves from the 2b side to the 2a side. do. A concave or V-shaped groove or the like is provided on the surface of the central magnetic pole 9 to serve as a guide for precise positioning during and after movement of the movable part 1, and the inner surface of this groove is used as a reference surface for sliding. To describe the transient state in which the movable part 1 starts moving from a stable state where it is attracted to either one of the electromagnet magnetic poles 2a or 2b to the other electromagnet magnetic pole, the optical path switching current generated by the drive current control circuit 7 The pulse activates the electromagnetic circuit. The polarity of the central magnetic pole 9 is the same as the magnetic pole on the moving direction side of the movable permanent magnet 1c (and magnetic poles 1d, 1e). Therefore, the distal end portion of the movable portion 1 in the moving direction receives a repulsive force from the central magnetic pole portion 9. Therefore, the static friction Fs generated at the contact surface between the movable part 1 and the concave groove or V-shaped groove surface for guiding the movable part 1 on the surface of the central magnetic pole 9 is:
Generally, it is expressed as Fs=ε _s N. Here, ε _s is the coefficient of static friction, N is the normal force to the guide surface, and is expressed as N=F _M ±W. F _M is the attractive force between the permanent magnet and the central magnetic pole 9, and W is the weight of the movable part 1.
Therefore, the attractive force becomes a repulsive force due to the switching drive pulse current, so F _M becomes -F _M ', and N=-F _M ±W
becomes. Here, in general, since F _M > W, N
becomes negative, and static friction can be ignored. After the movable part 1 starts moving, the attractive force between the opposite magnetic pole of the permanent magnet and the central magnetic pole 9 increases, but in this case, it becomes kinetic friction F _K , and generally F _K < F _S , so the movable part 1 The influence that prevents the movement of part 1 is small. This contributes to quick switching operation of the movable part. Furthermore, the coefficient of friction at the contact surface depends on the combination of materials, surface roughness, presence or absence of lubricant, amount, atmosphere,
Since it changes significantly depending on temperature, etc., these also need to be considered. Among these methods, when using a lubricant, it is necessary to consider the influence on the optical path entry and exit surfaces (increased light insertion loss), and in particular, the material and surface roughness must be sufficiently considered. Therefore, the contact surface between the movable part 1 and at least the concave groove guide surface on the surface of the central magnetic pole 9 is treated with a dry loop treatment having a small coefficient of friction (0.05 or less), for example, a Teflon-based material. Alternatively, the movable part 1 may be subjected to a surface treatment with a low coefficient of friction, or the inner surface of the guide groove, such as a concave shape, may be subjected to a wear-resistant surface treatment, such as Nidax treatment, or a hard Cr plating polishing treatment, to extend the service life and shorten the switching time. It is desirable to measure it.

The effects of the present invention can be summarized as follows.

Central magnetic pole 9 part and electromagnet magnetic pole 2a or 2b
On the other hand, by forming the magnetic path of the permanent magnet in the moving part, the conventional one-sided support becomes two-sided support,
It also improves performance against vibrations and shocks, increasing reliability.

Because of the three-magnetic pole structure in which the magnetic flux returns to the central magnetic pole part 9 via the yokes 8a, 8b and the electromagnet magnetic pole parts 2a, 2b, magnetic resistance is low, and power consumption is also low.

By adopting a three-magnetic pole structure, friction during driving can be reduced, so that the time required to change the optical path can be shortened.

Because the reference plane is fixed, reproducibility is improved,
Insertion loss fluctuations can be reduced.

Since the air gap length between the magnetic poles can be increased, the clearance for the shape, size, and alignment accuracy of the optical path changer (prism, mirror, lens, etc.) can be increased, improving workability.

FIG. 5 shows another embodiment of the present invention, and FIG. 6a
and b show a front view and a side view of the movable part 1 of the same embodiment. The difference from the example shown in Fig. 3 is that the electromagnet center magnetic pole 9 is made of a cylinder and is fitted into the center of the concave yoke part, and also that
As is clear from FIGS. and b, the movable part holder 1 has a groove along the moving direction of the movable part 1 on the top of the central magnetic pole 9 for guiding and positioning the movable part 1.
1 is provided, and the movable housing 1b is disposed within the groove of this movable part holder 11. The materials are the central magnetic pole part 9, the yokes 8a, 8b, and the electromagnet magnetic pole 2a,
2b Also, the magnetic poles 1d and 1e for permanent magnets are made of soft magnetic material, but the center magnetic pole member in particular is made of a material with a high maximum saturation magnetic flux density (2.0 wb/or more), such as super mendiure, and has a cross-sectional area. We are planning to reduce the number of Of course, the magnetic pole parts 2a, 2b, 1d, and 1e also
It may also be composed of a soft magnetic material with a large BHmax. The yoke parts 8a and 8b have a large initial permeability μi, for example, 78%.
The use of Ni permalloy, 45% Ni permalloy, etc. (both have an initial magnetic permeability of 10,000 or more) is the same as in the case of Fig. 3. It is preferable to use a non-magnetic material for the movable part holder 11, but if the diameter is approximately 1/2 or less of the length in the magnetization direction of the movable part 1, a magnetic material may be used. further increase. In addition, after the movable part holder 11 is fitted into the central magnetic pole part 9, it can be rotated and finely adjusted to align the optical axis with respect to the incident light, etc., which improves workability during assembly and adjustment, leading to improved performance. .

[Brief explanation of the drawing]

Fig. 1 is a three-dimensional diagram of the conventional example, Fig. 2 is a principle diagram of the conventional example, Fig. 3 is a three-dimensional diagram of an embodiment of the present invention, and Fig. 4 is a three-dimensional diagram of the conventional example.
5 is a sectional view of another embodiment of the present invention, FIG. 6 is a front view a and a side view of the movable part, and FIG. 7 is a diagram for explaining the operation of the optical path changer. It is. 1: Movable part, 1a: Prism, 1b: Movable housing, 1c: Permanent magnet, 1d, 1e: Magnetic pole piece,
2a, 2b: Electromagnet pole piece, 3a, 3b: wire ring,
4a, 4b: (non-magnetic material) magnetic pole holder, 5: Movable part holder (non-magnetic material), 6: board, 7: drive current control circuit, 8a, 8b: yoke, 9: electromagnet center pole piece, 10: Light rays, 10a, 10b: Outgoing rays,
11: Movable part holder (non-magnetic material or magnetic material), 1
2: Movable part holder surface treatment layer, 13: Movable part housing surface treatment layer.

Claims (1)

[Scope of Claims] 1. A three-pole yoke formed by integrating a central magnetic pole portion and a pair of magnetic pole portions disposed opposite to each other on both sides thereof, and a wire wound around the three-pole yoke. , means for generating predetermined magnetic poles in the pair of magnetic pole parts and the central magnetic pole part by applying current to the wire ring; Attraction between the generated magnetic poles and
A movable permanent magnet section that moves between the pair of magnetic pole sections due to repulsive force, and a movable permanent magnet section that is attached to the movable permanent magnet section and moves integrally with the movable permanent magnet section, and receives light when positioned on one side of the pair of magnetic pole sections. and an optical path changer comprising an optical element that refracts or reflects the light beam and outputs the light beam in a different optical path than the optical path of the light beam when the light beam is located on the other side of the pair of magnetic pole parts. Optical path changing device. 2. The optical path changing device according to claim 1, wherein the movable permanent magnet section is made up of a housing and a permanent magnet housed in the housing, and the optical path changing device is attached to the housing. Device. 3. Claims characterized in that a groove for stopping the rotation of the movable permanent magnet part is provided on the surface of the central magnetic pole part of the three magnetic pole yoke facing the movable permanent magnet part. 2. The optical path changing device according to item 1. 4. The optical path changing device according to claim 1, wherein a friction coefficient of a contact surface between the movable permanent magnet portion and the central magnetic pole portion of the three magnetic pole yoke is approximately 0.05 or less. 5. The optical path according to claim 1, wherein a contact surface between the movable permanent magnet part and the central magnetic pole part of the three-pole yoke is coated with a Teflon-based synthetic resin. Change device. 6. Claim 1, characterized in that the central magnetic pole part of the three magnetic pole yoke is formed into a cylindrical shape, and a non-magnetic polarity holder is fitted into the cylindrical central magnetic pole part. optical path changing device. 7. The optical path change according to claim 1, wherein the central magnetic pole part of the three magnetic pole yoke is formed of a soft magnetic material having a larger maximum saturation magnetic flux density than the other magnetic pole parts. Device. 8 Of the three magnetic pole yoke, the magnetic pole portion having a magnetic pole surface parallel to the movable permanent magnet surface has an initial magnetic permeability.
The optical path changing device according to claim 1, characterized in that the optical path changing device is made up of 10,000 or more soft magnetic materials.