JPH075372Y2 - Rotary encoder for micromanipulator using optical fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention mainly relates to a micromanipulator that drives microelectrodes in neurophysiology experiments, and more specifically to a rotary encoder that reads displacement of the micromanipulator. is there.

(Prior Art) Conventionally, a micromanipulator for piercing and driving a glass or metal microelectrode for deriving nerve activity or electrically stimulating nerve tissue in a neurophysiological experiment into a target brain region has been used. Has been used.

The position of the microelectrode should be adjusted by rotating the dial gauge 5 times per 500 μm.
It is read in an analog manner by counting the scale dial manually by dividing it into 0 equal parts and setting one scale to 10 μm, but repeating this work is not complicated and easy.

This problem can be solved by displaying the position of the microelectrodes digitally, and there are methods such as a method using a mechanical counter and a method in which the position is converted into an electric signal by a potentiometer or an encoder and then displayed digitally.

(Problems to be solved by the invention) Among those described in the related art, the method using an encoder is the most effective method in terms of reliability, easiness of handling and reading.

However, since the conventional encoder has a complicated structure, it is not easy to install it in the micromanipulator, and the mounting of the finished encoder requires a special mechanism for axis alignment or changes the shape of the micromanipulator. There is a problem of having to do it. The present invention has a simple structure in which a rotary encoder for converting the displacement of a micromanipulator used for experiments such as neurophysiology into an electric signal is detachably incorporated, and the above problem is solved by using an optical fiber. It is a thing.

(Means for Solving the Problems) In order to achieve the above object, the principle of the rotary encoder in the present invention will be described. A graduation ring rotatably incorporated in a micromanipulator is arranged along the circumference of the graduated ring. The reflection bands and the absorption bands are alternately arranged at equal intervals, and the reflection bands and the absorption bands are arranged with the same width, and the micromanipulator has,
An optical fiber is detachably attached to the scale ring to irradiate light with a light emitting diode, and a plurality of light receiving fibers for guiding the light reflected by the scale ring to a plurality of phototransistors are attached to and detached from the micromanipulator. It is a mechanism that is mounted as much as possible, periodically changes the amount of light incident on each of the light receiving fibers, and detects rotation by an electric signal by the phototransistor.

(Operation) The operation of the above configuration is as follows.

That is, if the scale ring installed in the micromanipulator rotates forward, the change of the incident light amount of one of the light receiving fibers leads the phase of the change of the incident light amount of the other light receiving fiber, and if it rotates in the opposite direction, the light receiving fiber of one of the light receiving fibers changes. The phase of the change of the incident light amount lags behind the change of the incident light amount of the other light receiving fiber.

Thus, the direction of rotation of the scale ring can be detected from the mutual phase relationship of the electric signals by the plurality of phototransistors, and at the same time, the position of the microelectrode can be determined by the relative phase of the electric signals. The displacement can be read digitally.

(Embodiment) An embodiment will be described with reference to the drawings. In FIG. 1 to FIG.
And illuminates the scale ring 3.

The light receiving fibers 4 and 5 guide the light reflected by the scale ring 3 and irradiate the phototransistors 6 and 7, respectively. The graduation ring 3 has light reflection bands 8 and light absorption bands 9 alternately arranged at equal intervals along the circumference thereof. When the scale ring 3 rotates, the amount of incident light on the light receiving fibers 4 and 5 changes periodically, and this is converted into an electric signal by the phototransistors 6 and 7. The sending optical fiber 1 and the receiving fibers 4 and 5 are arranged so that the irradiation area 10 of the sending optical fiber 1 and the receiving area 11 of the receiving fiber 4 overlap each other on the scale ring 3 as shown in FIG. 5 (a). Optical fiber 4
Detection area 12, the irradiation area 10 of the sending optical fiber 1 and the light receiving area 13 of the light receiving fiber 5 overlap, and the detection area 14 of the light receiving fiber 5, and the width of the reflection band 8 or the absorption band 9 in the circumferential direction. If it is a half cycle, the center of the detection area 12 and the center of the detection area 14 are displaced by a quarter cycle in the circumferential direction.

If the scale ring 3 rotates in the direction shown by the arrow in FIG. 4 or FIG. 5 (a), the change of the incident light amount of the light receiving fiber 4 advances in phase from the change of the incident light amount of the light receiving fiber 5, and in the opposite direction. When rotated, the change of the incident light amount of the light receiving fiber 4 is delayed in phase from the change of the incident light amount of the light receiving fiber 5. Therefore, the rotation direction of the scale ring 3 can be detected from the phase relationship between the electric signals by the phototransistors 6 and 7.

That is, when the scale ring 3 is rotated in FIG. 4, the electric signals obtained by the phototransistors 6 and 7 are as shown in FIG. 5 (b), so that the rotation angle (number) is digitally displayed. Is possible.

Specifically, as for the mechanism after the phototransistor, as shown in FIG. 5 (c), first, the sine wave signals output from the phototransistors 6 and 7 are sinusoidally amplified by the amplifiers P1 and P2, respectively, and then the waveform shaping is performed. The analog signals are converted to pulse signals by the circuits Q1 and Q2, and both pulse signals are input to the direction detection counter driver circuit R at the same time, and the rotation angle (number) is calculated here and displayed digitally on the display S. Just do it.

FIG. 1 is a schematic view of an embodiment of the present invention, in which the scale ring 3 is fixed to the feed screw 15 of the micromanipulator M, and the tip plug 17 of the optical fiber is inserted from the side surface of the micromanipulator M.

2 and 3 are a partial cross-sectional view of the micromanipulator M according to the present embodiment as seen from a side direction and a partial cross-sectional view as seen from above. The tip plug 17 is composed of an outer cylinder 19 having a key 18 and an inner cylinder 21 into which three optical fibers 20 are inserted.

The three optical fibers 20 are fixed in the inner cylinder by resin so as to form an equilateral triangle so as to correspond to the irradiation area 10 and the two light receiving areas 11 and 13 as shown in FIG. 5 (a). The tip plug 17 is attached to the micromanipulator M by the set screw 22.
It is fixed to the body. To adjust the position between the three optical fibers 20 with respect to the scale ring 3, the inner cylinder 21 is rotated and fixed by the set screw 23 when the phase difference between the centers of the detection areas becomes a quarter cycle.

(Effect of the Invention) Therefore, in the present invention, the tips of the three optical fibers for transmitting and receiving light having a constant diameter and opening angle are arranged in an equilateral triangle shape,
By configuring it so that it can be rotated and fixed,
It is possible to adapt to a graduation ring having a certain range of cycle length, and to increase the resolution of the encoder more than double that of the conventional configuration.
In addition, in using the micromanipulator equipped with the rotary encoder according to the present invention, (1) it becomes possible to read the positions of the microelectrodes digitally, so that the experimenter repeats the work of reading the fine scale during the experiment. This frees you from mental and physical fatigue and greatly improves work efficiency.

(2) Since the micromanipulator having the same shape as the conventional one can be used, it is not necessary to change the arrangement of the experimental equipment.

(3) Errors in reading the position of the microelectrode are reduced.

(4) Since the optical fiber is used, no artifact is given to the recording of the nerve activity.

(5) It is easy to attach and detach the micromanipulator and the optical fiber.

(6) Strong against mechanical shock and easy to handle. And so on.

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment of the present invention, FIG. 2 is a partial vertical sectional side view of an essential part of the micromanipulator of the present embodiment, and FIG. 3 is a partial vertical sectional plan view of XX portion in FIG. FIG. 4 is a perspective view showing the positional relationship between the scale ring and the optical fiber,
FIG. 5 (a) is a principle schematic diagram of the main part of the scale ring, FIG. 5 (b) is a principle explanatory diagram showing the phase relationship of the output signal waveform of the phototransistor, and FIG. 5 (c) is an analog signal. It is a circuit block diagram explaining the mechanism which carries out digital display as a pulse signal. M: Micromanipulator, 1 ... Transmission optical fiber, 2 ...
Light emitting diode, 4,5 ... Receiving fiber, 6,7 ... Phototransistor, 8 ... Reflection band, 9 ... Absorption band

Claims (1)

[Scope of utility model registration request] 1. A microscopic manipulator main body is provided with a graduated ring fixed to the shaft of a feed screw and arranged so as to alternately divide a reflection band and an absorption band of light having the same width so as to divide the outer periphery into N equal parts. The tip of one light-transmitting fiber that irradiates the surface with light and the two light-receiving fibers that receive the reflected light are equilaterally triangular and integrally rotatable, and the distance to the opposing scale ring can be changed. A rotary encoder for a micromanipulator using an optical fiber, which is arranged so that it can be fixed.