JPS5828615A - Measuring device for extent of shift - Google Patents

Abstract

PURPOSE:To obtain a small-sized measuring device for extent of shift which works on a single optical mark, by projecting the light to the optical mark through an optical fiber and counting the outputs of a pair of light receiving fibers arrayed in the shifting direction of the optical mark after converting these outputs into pulse signals. CONSTITUTION:An optical mark 1 containing reflective surfaces 3 and nonreflective surfaces 2 arranged alternately with an equal pitch is irradiated by the light given from a light source 5 via a projecting optical fiber 4c. The light reflected on the surface 3 is detected by light receivers 6a and 6b via light receiving fibers 4a and 4b. With this output of detection, the shifting direction of the mark 1 is detected via a direction detector 8. At the same time, the pulse is produced every time the mark 1 passes through the surface 3. These pulses are counted by an up-down counter 9 and then converted into analog signals through a D/A converter 10 to be used as the recording signals for an oscillogram, etc. In such a way, a small-sized measuring device for extent of shift which works on a single inexpensive optical mark can be obtained.

Description

[Detailed description of the invention] The present invention relates to an optical movement measuring device.

Conventionally, optical movement measuring devices for moving objects use two rows of optical marks with a phase shift, each mark is optically detected by two sets of light emitting and light receiving means, and its position is measured. The direction of movement of the optical mark was determined from the phase difference, and the amount of movement was determined by counting the number of marks that had passed. However, this method requires two rows of optical marks that are out of phase, and in order to prevent the two sets of light receivers from being affected by other marks, It is necessary to install them at intervals, which has the disadvantage that the detection part becomes large.

SUMMARY OF THE INVENTION An object of the present invention is to provide a compact movement measuring device for a detection unit that operates using a single optical mark.

An embodiment of the present invention will be described with reference to FIGS. 1 to 7. FIG. 1 shows an embodiment of the present invention. This movement measuring device consists of an optical mark 1 in which reflecting surfaces 3 and non-reflecting surfaces 2 are alternately and continuously arranged at equal intervals, and a light source 5 is used to project light onto the optical mark 1. Optical fiber for light 4C1 A first optical fiber for light reception 4a for guiding the reflected light from the optical mark 1 to the first light receiver 6a, a second optical fiber for light reception 4b for guiding the light reflected from the optical mark 1 to the second light receiver 6b, and a light receiver 6a. , 6b, a direction detector 8 which determines the moving direction of the optical mark 1 from the outputs of the optical marks 1 and outputs a pulse each time it passes the reflecting surface 3 according to the moving direction; an up/down counter 9 which counts the output pulses of the direction detector 8 according to the direction; It consists of a DA converter that converts the count results into analog signals.

The light-receiving optical fibers 4a and 4b are arranged shifted by X in the moving direction of the optical mark 1, as shown in FIG.

FIG. 3 is an explanatory diagram of the operation of the light receiving section. When the optical mark 1 moves in the entrance direction from the state shown in FIG. 3, the amount of light received by the second light-receiving optical fiber 4b increases due to the reflected light from the reflective surface 3b, and the light-receiving optical fiber 4a increases.

4b both receive light. When the optical mark 1 further advances in the direction A, the amount of light received by the second light-receiving optical fiber 4b decreases due to the non-reflective surface 2a, and no light is received.

Then, the amount of light received by the first light-receiving optical fiber 4a also decreases, and both light-receiving optical fibers 4a and 4b no longer receive light. When the optical mark 1 further advances in the entrance direction, the second light-receiving optical fiber begins to receive light by the reflecting surface 3a, and the same operation is repeated thereafter. At this time, the output of the first light receiver 6a is as shown in FIG. 4(2), and the output of the second light receiver 6B is as shown in FIG. 4(A). In FIG. 3, when the optical mark 1 moves in the B direction, it is the opposite of the case where it moves in the input direction, and the reflected light from the reflective surface 3 is first received by the first light receiving optical fiber, and the second light receiving optical fiber is received by the second light receiving optical fiber. The fiber 4b receives the light with a delay. The first light receiver 6a at this time
The output of the second light receiver 6b is as shown in FIG. 5(a), and the output of the second light receiver 6b is as shown in FIG. Therefore, the phase difference θ between the outputs of the light receivers 5a and 6b becomes reversed when the moving direction of the optical mark '1 changes.

FIG. 6 shows an example of a direction detector that outputs a pulse every time a reflective surface passes according to the moving direction of the optical mark 1.

The output of the first light receiver 6a is connected to the input of the waveform shaping circuit 13a, and the output of the second light receiving circuit 6b is connected to the waveform shaping circuit 13b. The rise of the output of the waveform shaping circuit 13a is detected by the capacitor 14a1, the resistor 15a1, and the diode 16a.
The inverter 18, the capacitor 14b1, the resistor 15b1, and the diode 16b detect the falling edge, and by ANDing each of them with the output of the waveform shaping circuit 13b, the reflective surface passes through the AND circuit 17a when the optical mark 1 moves in the input direction. outputs a pulse every time the AND circuit 17
b outputs a pulse when moving in the B direction. FIG. 7 shows waveforms at various parts of the circuit shown in FIG. 6 during operation.

The outputs of the AND circuits 17a and 17b in FIG. 6 are connected to an up/down counter 9 which increases the count when a pulse is applied to the up terminal and decreases the count when a pulse is applied to the down terminal. . AND circuit 17a
By connecting the output to the up terminal and the output of the AND circuit 17b to the down terminal, when the optical mark 1 moves in the in direction, the up/down counter 9 increases, and when it moves in the B direction, it decreases, so from the count result The amount of movement of the optical mark 1 including the direction can be measured. Further, the output of the up/down counter 9 is converted into an analog signal by an A/D converter 10, and can be used as a recording signal for an oscillogram or the like.

As described above, according to one embodiment of the present invention, it is possible to provide a small displacement measuring device that operates with a single inexpensive optical mark and has a detecting portion diameter several times that of the optical fiber used.

Figure 8 shows the detection unit facing the optical mark 1 when light is emitted and received using a plurality of optical fibers, with the light emitting optical fibers 4c, 4c', and 4c' in the center, and the first light-receiving fibers on both sides. Optical fibers 4a, 4a' and second light receiving optical fiber 4
b, 4b/ are arranged. By projecting and receiving light using a plurality of optical fibers in this manner, the sensitivity of the detection section can be increased.

Also, the center lines of the light emitting optical fibers 4c, 4c', 4c', the center lines of the first light receiving optical fibers 4a, 4a/, and the center lines of the second light receiving optical fibers 4b, 4b' are made almost parallel to each other. , by arranging the center lines of the light emitting optical fibers 4c, 4c' approximately in the center of the center lines of the first light receiving optical fibers 4a, 4a' and the center lines of the second light receiving optical fibers 4b, 4b/. The utilization rate of light from the optical fiber and the resolution of optical mark detection can be increased.

FIG. 9 is a partial sectional view of the side surface of the detection section shown in FIG. 8. As shown in this figure, the light emitting optical fibers 4C, 4C'
, 4C', first light receiving optical fiber 4a.

4a/ and the second light-receiving optical fibers 4b, 4b/ are collectively fixed by the support member 22, and the structure is simplified by housing these optical fibers in one coating, which facilitates manufacturing. An economical detection unit can be obtained. In addition, the light emitting optical fiber 4C1 and the light receiving optical fiber 4
By housing a and 4b in one cover, the detection section can be made easy to handle.

The width of the reflective surface of the optical mark 1 that can be used in the present invention is proportional to the distance X between the centers of the first light-receiving optical fiber 4a and the second light-receiving optical fiber 4b of the detection section. In Fig. 8, X is approximately 1.74 times the optical fiber diameter, in the arrangement shown in Fig. 10, X is approximately the same as the optical fiber diameter, and in the arrangement shown in Fig. 11, it can be less than or equal to the optical fiber diameter. .

Another method for improving the resolution of the detection section is to provide a lens at the tip of the detection section, as shown in FIG.

In the direction detection circuit shown in FIG.
When one passes through the detection section, only one pulse is generated. This is because only the beginning or end of the reflective surface is detected. The direction detection circuit shown in FIG.
and AND circuits 20 and 21 are added, and the waveform shaping circuit 13
A pulse is generated at the rise and fall of the output of a. That is, the beginning and end portions of the reflective surface 3 are detected when the reflective surface 3 is passed through.

FIG. 14 shows waveforms at various parts of the circuit shown in FIG. 13 during operation.

In this way, when passing through the reflective surface 3, the reflection surface 3 moves from the non-reflective surface 2.
Detect the boundary from the non-reflective surface 2 to the reflective surface 3,
By counting both of them, the resolution can be reduced to two.

According to the present invention described above, it is economical because it operates with a single inexpensive optical mark, and also has the effect that the detection section can be made small, about several times the diameter of the optical fiber used.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the configuration of a measuring device according to an embodiment of the present invention;
Figures 2 to 7 are explanatory diagrams of the operation of Figure 1, and Figures 8 to 14.
The figures are explanatory diagrams of different embodiments of the present invention. DESCRIPTION OF SYMBOLS 1... Optical mark, 4a... Optical fiber for first optics, 4b... Optical fiber for second optics, 4c... Optical fiber for light projection, 6a, 6b... Light receiver, 8.・・Direction detector, Deafness 4 cause 5 Deafness 1 '4 '7 A'') 5?; ] to object transfer SS direction 1 = movement or

Claims (1)

[Claims] 1. Eight light projecting means consisting of an optical mark in which ranges with different reflectances are alternately and consecutively arranged at a predetermined pitch at predetermined intervals, and an optical fiber and a light source that project light onto the optical mark. and,
A first light-receiving optical fiber that receives reflected light from the optical mark, a second light-receiving optical fiber that is displaced from this in the direction of the movement axis of the optical mark, and an optical signal of each light-receiving optical fiber. A first light receiver and a second light receiver that convert the signals into electrical signals, a direction detector that generates a pulse from the output signals of these light receivers each time the optical mark passes a reflective surface according to the moving direction of the optical mark, and A movement amount measuring device comprising an up/down counter that counts pulses according to the direction of movement of an optical mark. 2. In the item described in claim 1 above, the center line of the light-emitting optical fiber, the center line of the first light-receiving optical fiber, and the center line of the second light-receiving optical fiber are made substantially parallel to each other. A movement measuring device characterized by: 3. A movement measuring device according to claim 1, characterized in that the projection optical fiber, the first light-receiving optical fiber, and the second light-receiving optical fiber are fixed together. 4. In the item described in claim 1 above, the up/down counter is configured to count both the boundary from the reflective surface to the non-reflective surface and the boundary from the non-reflective surface to the reflective surface of the optical mark. A movement measuring device characterized by: