JPH0434401Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is designed to prevent light beams emitted from one of the light-emitting elements to one of the light-receiving elements by the object to be measured, or to condense the beam. The present invention relates to a position detection device that detects the position of an object to be tested.

[Prior Art] Conventional technology detects the position of a test object by blocking or condensing the light flux emitted from one of the light emitting element groups to one of the light receiving element groups. In a position detection device, it is difficult to improve the resolution of position detection more than the interval between light emitting elements or the interval between light receiving elements. Therefore, when performing measurements that require high resolution, the resolution is improved by closely arranging small light emitting elements or light receiving elements.

[Object of the invention] An object of the invention is to eliminate the above-mentioned problems and provide a position detection device that has high resolution without increasing the number of light emitting elements and light receiving elements.

[Summary of the invention] The gist of the invention to achieve the above objectives is as follows:
It consists of a plurality of light emitting elements arranged in a row at predetermined intervals, a plurality of light receiving elements arranged parallel to the light emitting elements at a predetermined interval, and a control circuit for controlling the driving of the light emitting elements and the light receiving elements. , a position detection device that detects the position of a test object by causing a light flux to reach the light receiving element via a test object that obstructs the straightness of light from the light emitting element, the control circuit is the light emitting element (or the light receiving element)
The light emitting element (or The position detection device is characterized in that it has a function of sequentially switching and repeating the above-mentioned light-receiving elements.

[Principle of the invention] The basic principle of the invention will be explained based on FIG. A plurality of light emitting elements 1a, 1b, 1c, . . . arranged in a straight line at regular intervals, and a plurality of light receiving elements 2a, 2b, 2c, . . . arranged parallel to these light emitting elements 1 at regular intervals. The test object O is arranged to face the light emitting element 1 and the light receiving element 2 along a straight line P between the light emitting element 1 and the light receiving element 2. Note that one light emitting element 1 has M
(M is an integer of 2 or more) light receiving elements 2 correspond, and the straight line P is at a distance of W/M from the light emitting element 1 side,
Further, it is assumed that the distance is W·(M−1)/M from the light receiving element 2 side.

FIG. 1 shows a case where, for example, one light emitting element 1 is associated with five light receiving elements 2, and the straight line P is at a distance of W/5 from the light emitting element 1 side. If the spacing between the light receiving elements 2 is D, and the light receiving elements 2a to 2e correspond to the light emitting element 1a, and the light receiving elements 2b to 2f correspond to the light emitting element 1b, then the light receiving elements 2a to 2a correspond to the light emitting element 1a.
The light beams emitted from each of the light emitting elements 2e intersects the straight line P at five points, and together with the intersection points of the light beams emitted from the light emitting element 1b, there are a total of distance D/5 intervals on the straight line P.
10 intersection points are formed. Next, if we add the 5 points of intersection between the light beam emitted from the light emitting element 1c to each of the light receiving elements 2c to 2g and the straight line P, a total of 15 points of intersection will appear on the straight line P intermittently at distance D/5 intervals. It is formed. Therefore, the object O moving on the straight line P has a resolution of D/5 due to these intersection points, that is, the light receiving element 2
It is detected with a resolution of 1/5 of the distance D between the two.

In this way, when M light receiving elements 2 correspond to one light emitting element 1, the resolution is 1/M of the distance D between the light receiving elements 2. Furthermore, it is clear that even if the positions of the light-emitting elements 1 and the light-receiving elements 2 are swapped to provide M light-emitting elements 1 and one light-receiving element 2, the resolution will be 1/M.

[Embodiments of the invention] The invention will be explained in detail based on the embodiments shown in FIG. 2 and below.

FIG. 2 is a block diagram when detecting the movement of a float of an area type flowmeter as a test object, and has a configuration in which one light-emitting element 11 corresponds to two light-receiving elements 12. The output of the controller 15 is connected to a driver 13 that drives one light emitting element 11 and a driver 14 that drives a plurality of light receiving elements 12 . The light beam emitted from the light emitting element 11 passes through the glass tube 16 of the area type flowmeter, enters the light receiving element 12, and is converted into an electric signal. The output of the light receiving element 12 is output as a 4-20 mA analog signal from the output terminal OUT via the counter 17, the D/A converter 18, and the 4-20 mA converter 19 in this order.

In the position detection device configured in this way,
Controller 15 has driver 13 and driver 1
4, the light emitting element 11 and the light receiving element 12 are connected to the third
Drive sequentially according to the timing chart shown in the figure. That is, first, the light emitting element 11a and the light receiving element 12a are driven, then the light emitting element 11a and the light receiving element 12b are driven, and then the light emitting element 11b and the light receiving element 1 are driven.
2b, the light emitting element 11 and the light receiving element 12 are sequentially removed in the same way as the light emitting element 11b and the light receiving element 12c.
drive one set at a time.

The light beam emitted from the light emitting element 11 is transmitted through the glass tube 16.
However, when the float 20 made of an opaque body that moves up and down in the glass tube 16 according to the flow rate is at the position shown by the solid line in FIG. 4, for example, the light emitted from the light emitting element 11b The emitted light flux does not reach the light receiving element 12b, and the light receiving element 12
No signal is output from b. But at this time,
The light beam between the pair of light emitting element 11b and light receiving element 12c is not blocked by the float 20, and the light beam between the light receiving element 12c
A signal will be output from c.

As a result, the output of the light-receiving element 12 becomes an output in which the signal of the combination of the light-emitting element 11b and the light-receiving element 12b is missing as shown in FIG. The counter 17 counts the output pulses of the light receiving element 12 until a pulse corresponding to a certain light receiving element 12 is lost, and outputs the counted signal to the D/A converter 18 as a position signal of the float 20. After the D/A converter 18 converts the digital signal into an analog signal, the 4 to 20 mA converter 19 converts the digital signal into an analog signal.
A 20 mA current loop signal is generated and the position information of the float 20 is output to the output terminal OUT.

In this case, since two light receiving elements 12 correspond to one light emitting element 11, the signal output to the output terminal OUT has a resolution of 1/2 of the distance D between the light receiving elements 12. become.

In this case, as shown in FIG. 6, one-dimensional condensing lenses 21, 2
2, it becomes possible to detect the position of the float 20 by using a weak light beam between them as an afocal light beam.

In the embodiments shown in FIGS. 4 and 5, position detection is performed using the light shielding effect caused by the presence of the opaque float 20 on the optical path connecting the light emitting element 11 and the light receiving element 12. There is. but,
As shown in FIG. 6, by making the float 20 a transparent sphere, the luminous flux emitted from the light emitting element 11 is focused onto the light receiving element 12 by the lens effect.
Position information of the float 20 can also be obtained. That is, the float 20 connects the light emitting element 11 and the light receiving element 12.
If the light is on the optical path connecting the
The output level of 2 becomes large. Therefore, the position of the float 20 can be detected based on the output level of each light receiving element 12.

Furthermore, in the above embodiment, for all combinations of two light receiving elements 12 corresponding to one light emitting element 11, from the light emitting element 11 to the light receiving element 1
2, the position of the float 20 is detected. However, by not using some of the combinations of one light emitting element 11 and two corresponding light receiving elements 12 for position detection, that is, not outputting from a specific light receiving element 12, position information can be obtained. can be given weight.

For example, the scale of the glass tube 16 of an area flowmeter is not linear with respect to the flow rate, but in a part where the scale intervals are small, all the light emitting elements 11 and light receiving elements 12
If the position of the float 20 is detected for the set, and the output of a specific light receiving element 12 is ignored in areas where the scale interval is coarse, the position information output to the output terminal OUT can be made linear with respect to the flow rate. becomes possible.

[Effects of the Invention] As explained above, the position detection device according to the present invention can perform high-resolution position detection without downsizing or increasing the number of light-emitting elements and light-receiving elements.

[Brief explanation of the drawing]

Drawings Fig. 1 is an explanatory diagram of the principle of the position detection device according to the present invention, Figs. 2 to 6 show embodiments, and Figs.
The figure is a configuration diagram when applied to an area type flowmeter.
The figure is an output time chart of the light-emitting element and the light-receiving element, Figure 4 is an explanatory diagram of the positional relationship between the light-emitting element, the light-receiving element, and the float, and Figures 5 and 6 are explanatory diagrams of modified examples of the position detection means. . 1 and 11 are light emitting elements, 2 and 12 are light receiving elements, 13 and 14 are drivers, 15 is a controller, 16 is a glass tube, 17 is a counter, 18 is a D/A converter, 19 is a 4 to 20 mA converter, and 20 is a Floats 21 and 22 are condenser lenses.

Claims (1)

[Claims for Utility Model Registration] 1. A plurality of light emitting elements arranged in a row at predetermined intervals, a plurality of light receiving elements arranged parallel to the light emitting elements at a predetermined interval, and driving of the light emitting elements and the light receiving elements. and a control circuit that controls the light emitting element, and a position where the position of the object to be detected is detected by allowing the light flux to reach the light receiving element via the object to be measured that obstructs the straightness of light from the light emitting element. In the detection device, the control circuit is configured to drive one of the light emitting elements (or the light receiving element), and to detect a plurality of the light receiving elements (or the light receiving elements) corresponding to the light emitting element (or the light receiving element). 1. A position detection device having a function of repeatedly driving the light emitting elements (or the light receiving elements) one by one while sequentially switching the light emitting elements (or the light receiving elements). 2. Scope of the Utility Model Registration Claims: The control circuit repeats sequentially driving a plurality of corresponding light-receiving elements while one of the light-emitting elements is emitting light, while switching the light-emitting elements. The position detection device according to item 1. 3. Scope of the Utility Model Registration Claim: The control circuit repeats sequentially causing a plurality of corresponding light-emitting elements to emit light while driving one of the light-receiving elements while switching the light-receiving elements. The position detection device according to item 1. 4. The control circuit drives some of the corresponding light-receiving elements (or light-emitting elements) in a specific order while driving one of the light-emitting elements (or light-receiving elements). A position detection device according to claim 1, wherein weighting is applied to position information of a test object. 5. The position detection device according to claim 1, wherein the object to be inspected is a light shielding body. 6. The position detection device according to claim 1, wherein the object to be detected is a transparent body having a lens effect.