JPH04357403A - Position detecting apparatus - Google Patents

Abstract

PURPOSE:To obtain a position detecting apparatus for detecting the position of a moving object which can mechanically and electrically adjust a detecting signal obtained in accordance with the positional relationship between the moving object and a detector. CONSTITUTION:When each electric positional detecting signal X1, X2 output from a PSD 11 is input to a differential amplifier 13 without attenuation, a position signal can be output in accordance with the mechanical positional relationship between an object to be detected and the PSD 11. If the level of the input signal to the differential amplifier 13 is changed by variable resistors 12a, 12b respectively for adjusting the X1, X2 signals, the zero cross point can be moved falsely in the X1 or X2 direction, thus enabling the electric adjustment.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detection device for detecting the position of a moving object.

0002

2. Description of the Related Art Conventional position detectors for moving objects include transmission-type photosensors and reflection-type photosensors.

[0003] A conventional position detector will be explained below. Figure 5 shows the configuration of a conventional position detector.
5A is a conceptual diagram of a reflection type photo sensor, and FIG. 5(b) is a conceptual diagram of a transmission type photo sensor. On the other hand, FIG. 6(a) shows the internal configuration,
(b) shows the configuration of the output signal. 5 and 6, 21 is a light emitting element, 22 is a light receiving element,
23 is a reflecting object, 24 is a detection object, 25 is incident light, 26
is the position signal output.

The operation of the position detector configured as described above will be explained below. First, Figure 5(a)
The operation of the reflective photosensor is that when the reflective object is on the reflective surface a, the incident light 25 emitted from the light emitting element 21 is reflected on the reflective object 2.
3 and enters the light receiving element 22. At this time, the phototransistor which is the light receiving element 22 is turned on and the position signal output 26
output. In addition, the operation of the transmission type photosensor shown in FIG. 5(b) is such that when the detection object 24 passes through the gap (D) forming the housing, the light from the light emitting element 21 is blocked and the phototransistor which is the light receiving element 22 is turned off. A signal is detected.

[0005]

[Problems to be Solved by the Invention] However, in the above-mentioned conventional configuration, the detection position and accuracy of the detection object depend on the size of the pinhole or slit in front of the light receiving element, and in order to adjust the detection position, a reflective Adjustments must be made by moving the position of the type photo sensor or transmission type photo sensor and the absolute position of the moving object. In order to accurately adjust the detection position, there was a problem in that it was necessary to provide a mechanism that could be moved minutely.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and aims to provide a position detection device that can electrically adjust the detection position of a moving object with high precision.

[0007]

[Means for Solving the Problems] In order to achieve this object, the present invention receives reflected or transmitted light based on the position information of an object to be positioned, and measures at least an inverse proportion according to the position of the received incident light. a position sensing detector that outputs electrical position signals X1 and X2 having the following relationship; a differential amplifier that takes and amplifies the difference between both of the electrical position signals X1 and The present invention is provided with a zero-crossing point predetermined based on the above and a zero-crossing detector that detects the position where the output of the differential amplifier becomes zero.

[0008] Secondly, the output electrical position signals X1 and X are sent to the position sensing detector.
A variable resistor is added to adjust 2.

[0009]

[Operation] With the above configuration, the present invention provides electrical position signal
It is possible to detect the light incident on the center position of the linear sensor by passing the differential signal of X1 and can be adjusted accordingly.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows a PSD (Position Ssen) which is a main part of a position detection device in an embodiment of the present invention.
11 shows an equivalent circuit of a position sensing detector (sing detector) 11. Figure 2
, light from a light emitting element (not shown) is arranged so as to be focused on a linear sensor according to the movement of a moving object, and when the incident light is scanned from the X1 direction to the X2 direction, the resistors R1 and R2 The output signals of X1 and X2 increase or decrease depending on the light condensing position, respectively, according to the ratio of .

The principle of the PSD 11 is that when light is focused on a sensor, the light energy is converted into voltage by a silicon photosensor, and X1 and X2 are divided and output. The voltage Vh generated by this photosensor is output as a resistance divided value based on the position of the incident light, the resistance value R1 of X1, and the resistance value R2 of the position of the incident light and X2.

[0013]

[Math 1]

In other words, (Equation 1) is obtained. Figure 1 shows the circuit of a position detection device in an embodiment of the present invention using the PSD11 having such characteristics as a detector, and Figure 3 shows the signal waveform at each point, and the signal waveform at each point when electrically adjusted. Figure 4 shows the signal of
Shown below.

In FIG. 1, 11 is the PSD shown in FIG.
, 12 is the electrical position signal X1, which is the output of the PSD 11.
Variable resistor for adjusting X2, 13 is electrical position signal X1
, X2 as inputs, 14 is the differential amplifier 13
This is a zero-cross detector that detects the zero-cross (that is, the point where the electrical position signals X1 and X2 are balanced).

The operation of the position detection device constructed as described above will be explained with reference to FIGS. 3 and 4.

First, when the light from the light emitting element scanned by the movement of the detection object moves in the linear direction of the PSD 11, and the voltage output by the incident light moves from the X1 direction to the X2 direction, the voltage shown in FIG. As shown, each signal of X1 and
becomes.

Further, such a signal is
When the calculation of 1-X2 is performed, a differential signal 17 that becomes zero at the midpoint is output as shown in FIG. 3(b). Furthermore, the differential signal 17 is passed through the zero cross detector 14 to generate a detection position signal 18 that outputs an H level signal when the light from the light emitting element passes through the midpoint, as shown in FIG. 3(c). Output.

This method uses the X1 output from the PSD11.
, The electrical position signal of X2 is used as an input signal to the differential amplifier 13, and the variable resistor 1 for adjustment is
By changing the level at 2b, the zero crossing point can be changed in a pseudo manner in the X2 direction as shown in FIG. 4(a). Similarly, by changing the electrical position signal of X1 using the variable resistor 12a, the zero crossing point can be changed in a pseudo manner in the X1 direction.

As described above, according to this embodiment, the PSD 11 is used as a position detector, and the point where the difference signal is zero is detected using the position signals X1 and X2 via the zero cross detector 14. Furthermore, by adjusting the X1 and X2 signals input to the differential amplifier 13 using the variable resistors 12a and 12b, the position of the moving object can be electrically changed.

In this embodiment, a linear PSD sensor was explained as a position detector, but the two-dimensional center position can also be adjusted using a similar circuit configuration in the incident light pointing method using a two-dimensional PSD. It goes without saying that it can be done.

[0022]

As described above, the present invention has the advantage of being able to adjust the position detection of a moving object over a wide range by using a PSD detector as a position detection device and providing a circuit that can electrically adjust the detection position. This makes it possible to realize a position detection device.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a position detection device according to an embodiment of the present invention.

[Figure 2] P which is the main part of the position detection device in the same embodiment
SD equivalent circuit diagram

[Figure 3] Main part waveform diagram of the position detection device in the same embodiment

[
Figure 4: Main part waveform diagram of the position detection device in the same embodiment

[Figure 5] (a) Conceptual diagram of a conventional reflective photo sensor (b) Conceptual diagram of a conventional transmissive photo sensor

[Figure 6] (a) Equivalent circuit diagram of a conventional photosensor (b) Output waveform diagram of the same photosensor

[Explanation of symbols]

11 PSD 12 Variable resistor 13 Differential amplifier 14 Zero cross detector

Claims (2)

[Claims] Claim 1: A position for receiving reflected or transmitted light based on position information of an object to be positioned and outputting electrical position signals X1 and X2 having an inversely proportional relationship at least according to the position of the received incident light. - A sensing detector, a differential amplifier that takes and amplifies the difference between both the electrical position signals X1 and X2, and a zero cross point predetermined based on the position information of the object to be measured and the output of the differential amplifier. A position detection device comprising a zero cross detector that detects a zero position. 2. The position detection device according to claim 1, wherein the position sensing detector includes a variable resistor for adjusting the output electrical position signals X1 and X2.