JP3256764B2 - Wide range position detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a position detector. More specifically, the present invention relates to a position detector capable of detecting an accurate position over a wide range, comprising a tool for diffusing a light beam by transmission and a plurality of light detectors for capturing light diffused by the tool.

[0002]

2. Description of the Related Art Conventionally, a method of detecting a position using a light beam has been performed. However, these methods are roughly classified into the following three methods.

[0003] First method, semiconductor type by irradiating a light beam directly to the semiconductor element, finely separated on the semiconductor element, the more light into a number of highly sensitive light detector that is provided to the one by one There are those that detect the position by capturing, and those that attach a four-divided element or a center electrode, attach electrodes to the left and right, and use the difference in resistance between the right and left to detect the light spot position. Although this method is excellent in resolution and high in sensitivity, it is limited to the material of a semiconductor element, so that it can be made only a small one, and has the disadvantage that it is very expensive.

[0004] The second method, a television camera type, this
This is a method in which a light beam is captured by a light detector through a television camera . This method has the advantage that the accuracy of the resolution is of the ordinary level but the stability is good. However, this method tends to have an excessively large outer shape, especially the depth, and requires not only the electrical system necessary for analyzing the captured light but also the electrical system that moves the TV camera body. There are too many drawbacks,
The disadvantage is that the optical system also has limitations.

A third method is a fiber input type .
In this method, the position is detected by irradiating a light beam to a system in which fiber-type optical detectors are arranged in the horizontal direction.This method has the advantage that the resolution is normal, but the linearity is good. I have. However, this method also has the disadvantage that the apparatus tends to be large-scale, as in the case of the above-mentioned television camera type, and in particular, it is difficult to manufacture a two-dimensional apparatus and a high-resolution apparatus cannot be obtained.

[0006]

SUMMARY OF THE INVENTION The present inventor has solved the above-mentioned drawbacks of the prior art, has high resolution and stability, has good linearity, is compact, is convenient to handle, and has high accuracy over a wide range. As a result of intensive studies to develop a position detector capable of detecting a position, the present invention has been completed.

[0007]

SUMMARY OF THE INVENTION The present invention provides a long one-dimensional
Wide-area position detector (first invention) and two-dimensional wide area
Features a position detector (second invention)
However, it is as follows.

[0008] First of all, the long one-dimensional wide area according to the first invention
The feature of the position detector is that
The diffusion pattern of the light beam (1) is set to the central axis of the diffusion pattern.
(6) A horizontally long transmissive diffusion plate that diffuses symmetrically to (6)
And a light beam transmitted through and diffused through the horizontally long transmission type diffusion plate (2).
Multiple light detectors to capture the diffused light of the
And a detector substrate (3) provided.
The beam (1) is a device that is modulated like laser light or LED.
Used, and the detector substrate (3) is the horizontal transmission type
Parallel to the diffuser (2), this includes the light detector (4a) (4
b) (4c) (4d)
The photodiodes are arranged at uniform intervals and are expanded by the photodiode.
Capturing diffused light, two or three or more
Select a little more and measure the relative output difference and
Convert analog linearizer or measured value to ROM as it is
Calculation by the correction means that replaces
By differentially amplifying the output,
The point is to detect it.

[0009] In addition, two-dimensional wide-range position detector features
The sign is the light after transmission Beam (1)
Turn the turn horizontally and vertically with respect to the central axis (6) of the diffusion pattern
A transmission type diffusion plate (5) for diffusing two-dimensionally
The diffused light of the light beam (1) that has passed through and diffused through the
Detector with multiple light detectors to capture
A substrate (3a), wherein the light beam (1) is a laser
-It should be modulated like light, LED, etc.
The reflector substrate (3a) is parallel to the transmission type diffusion plate (5).
Light detectors (4a) (4b) (4c) (4d)
Photodiodes are placed at equal intervals on the four corners or cross-hairs
And two-dimensional by the photodiode.
Captures diffused light and outputs 2 or 3 or
Select a little more and measure the relative output difference and
The analog linearizer or the measured value is directly stored in ROM
And perform a correction operation using correction means
Illuminated position by differentially amplifying each output
Is detected.

[0010] Summary of the wide position detector according to the above two invention, thereby realizing a high position detection precision by capturing the diffused light the light beam (1) after diffused by the transmission to the plurality of light detectors But
In each case , focusing on the point that the diffusion pattern of the light beam becomes symmetrical with respect to the center line of the incident beam, and capturing the diffused light by a plurality of light detectors at different positions, the electric power obtained from the light detector is obtained. By analyzing the output difference of the signal, a long, one-dimensional wide-range position detection
As a detector or as a two-dimensional wide-range position detector, a position detector having a wide range and high resolution and high stability can be realized.

[0011]

Next, the present invention will be described with reference to examples, but the present invention is not affected at all.

[0012] Examples of the position detector according to the present invention is realized by a one-dimensional model (long type one-dimensional wide position Detection
1 ) will be described with reference to FIG. In this example, the light beam
The laser beam as (1), is transmitted against the laterally elongated thickness 2 mm transmission diffusion plate made of white acrylic resin plate was used as a diffusion ingredient (2), said transmission
A plurality of light detectors (4a) (4b) (4c) (4d) that are located parallel to the mold diffuser (2) and are evenly spaced on it
(4e) to deploy the detector substrate (3) having a (4f), this
These light detectors (4a), (4b), (4c), (4d), (4e), and (4f) perform position detection by capturing diffused light.
In this case, the laser beam transmitted through the diffusion plate 2 is shown in FIG.
As shown in the diffusion pattern by the angle from the center shown in
As the angle increases from the center axis,
And the amount of light in the direction going straight is maximized.
You.

[0013] Figures 2 and 3 the principle of position detection in this case
It will be explained by. The light beam (1) transmitted through the horizontally long transmissive diffuser (2) loses its directivity due to scattering inside the horizontally long transmissive diffuser (2). Has a symmetrical diffusion pattern on the central axis (6) of the light beam (1).

In FIG . 2, the center axis (6) of the diffusion pattern coincides with the center line (7) between the light detectors (4a) and (4b) . In this case, the light detector (4a) and the light An electrical output is obtained at both detectors (4b) , but the output is equal and thus the output difference is zero. this is
At the center axis (6) of the laser beam diffusion pattern after transmission
If the angles are the same, the intensity of light traveling in that direction is equal
Because it becomes difficult.

[0015] However transmission of the light beam (1) as shown in Figure 3
When the central axis of the diffusion pattern after (6) is biased towards the light detector (4a), the output of the light detector (4a) is
The output becomes larger than the output of the light detector (4b) , and by measuring the relative output difference, the position where the transmitted light beam (1) is irradiated can be detected.

[0016] The light detector (4a) and light detector (4b)
By differentially amplifying each output of the optical detector, the optical detector (4
The center detector (7 ) between a) and (4b) serves as a position detector that outputs the position information positively and negatively with the center line (7) being zero. The output of this differential amplification is generally as shown in FIG. 4, although it depends on the state of diffusion.

As can be seen from FIG . 4, quite good linearity can be obtained near the center, but the distortion increases as the distance from the center increases. Therefore, the linearity can be corrected by an analog linearizer or the like, or the measured value can be used as it is. If the data is converted to a ROM and replaced with a straight line to perform a correction operation, linearity can be ensured over the entire area.

The optical detector laterally to the detection principle to that shown in FIG. 1 described above (4a) (4b) (4c ) (4d) (4e) (4
f) is realized as a long one-dimensional position detector in which a large number of f) are arranged. In this long type, the light beam
The light detectors (4a), (4b), (4c), (4d),.
Number, line the correction operation by selecting little more in some cases
U.

The reason is if in the middle near the center of the irradiation position two optical detectors <br/> chromatography (4a) (4b) is the sensitivity is satisfactory, the irradiation position is either one of the light detectors ( 4a)
(4b) If it is near the upper part, the sensitivity drops as shown in Fig. 4.Therefore, it is better to perform differential amplification or correction operation using the next adjacent optical detector (4c) (4d). is there.

Furthermore this structure shows what developed two-dimensionally in FIGS. 5 and 6, whereby it is possible to perform simultaneously detecting the positions in the vertical direction as well as horizontally.

[0021] In this case also uses the thickness of 2 mm white acrylic plate as transmissive diffusion plate (5), a number of light detectors for capturing the diffused light diffused by transmitting by irradiating a light beam (1) (4a) (4b) (4c) (4d) at the four corners (Fig. 5) or
The detector substrate (3a) arranged at equal intervals (FIG. 6) on the cross line is disposed on the diffusion side of the transmitted light beam (1) .

In this case, the light detector (4
between the total output of a) (4b) (4c) ( horizontal photodetector <br/> over the arrangement of 4d) (4a) (the total output and the light detector of 4b) (4c) (4d) detected by performing the calculation, the vertical direction is detected by performing arithmetic operations with the total output of the total output of the optical detector of the optical detection <br/> compactors (4a) (4c) (4b ) (4d).

[0023] The light detector (4 in order to prevent this time interference
a) Each of the optical detectors (4a) (4b) (4) is such that the straight line connecting (4c) and the straight line connecting the optical detectors (4c) and (4d) are orthogonal to each other.
c) Place (4d) .

In the case of FIG . 6, the horizontal direction is a light detector.
(4a) By the output of (4b) , the vertical direction is the optical detector (4c)
Calculation and detection can be performed by the output of (4d) . In this case also the light detector (4a) connecting (4b) lines and optical law detector <br/> coater (4c) each light <br/> detector as the line connecting the (4d) perpendicular to each other (4a) ( 4b) (4c) and (4d) are arranged .

In this two-dimensional type, the scale can be increased as in the one-dimensional type, and a transmission type diffusion plate (5) larger than that shown in FIGS. An optical detector (4) having an arrangement as shown in FIG.
a) (4b) (4c) (4d) further multiple deployment was detector substrate (3
By using a) , four or more optical detectors can be selected from these optical detector groups in descending order of signal intensity, and their outputs can be calculated to perform highly accurate position detection.

The optical beam is incident light to be used in the present invention
As (1) , DC light can be measured in each differential operation, but it is better to demodulate and calculate modulated light such as laser light or LED in order to increase accuracy. Further, as the transmission type diffusing material, a white acrylic resin plate or a white styrene resin, a resin plate containing a diffusing agent such as a metal powder or a pigment, a ground glass, a white glass, a metal powder or a pigment glass or the like containing a diffusion agent and the like is that is suitable. Also as the light detector is suitably a photodiode.

[0027]

As described above, the wide-range position detector according to the present invention diffuses the light beam (1) by transmission, and then captures the diffused light by a plurality of light detectors to perform highly accurate position detection. Not only can this be realized, but also a stable and high linearity detector can be provided, and a small-sized and convenient wide-range position detector can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment in which a wide-range position detector according to the present invention is realized by a one-dimensional model.

FIG. 2 is an explanatory diagram showing a principle of position detection of a wide-range position detector according to the present invention.

FIG. 3 is an explanatory diagram showing a principle of position detection of a wide-range position detector according to the present invention.

FIG. 4 is a diagram showing a relationship between a light beam irradiation position and a differential amplification output of each optical detector in the explanatory diagrams shown in FIGS. 2 and 3.

FIG. 5 is a schematic diagram showing an embodiment in which the present invention is realized by a two-dimensional model.

FIG. 6 is a schematic diagram showing another embodiment in which the present invention is realized by a two-dimensional model.

[Explanation of symbols]

 (1) Light beam (2)Horizontal transmission diffuser  (3)(3a) Detector board(4a) (4b) (4c) (4d) (4e) (4f) lightDetector (5)Transmissive diffuser  (6) Center axis of diffusion pattern (7) Center line between detectors

Claims (2)

(57) [Claims] 1. A diffusion pattern of a light beam (1) after passing therethrough.
Is diffused symmetrically with respect to the central axis (6) of the diffusion pattern.
A horizontally elongated transmission type diffusion plate (2), and the horizontally elongated transmission type diffusion plate
Captures the diffused light of the light beam (1) transmitted and diffused through (2)
Detector board with multiple light detectors (3)
And the light beam (1) is a laser beam, an LED, or the like.
Use the one that is modulated like
The plate (3) is parallel to the horizontally long transmission type diffusion plate (2).
Are optical detectors (4a) (4b) (4c) (4d)
Photodiodes are arranged at equal intervals.
The diffused light is captured by the
Select two or three or a little more
Measure force difference and use analog linearizer or actual
Correction means to convert measured values to ROM and replace them with straight lines
Compensation calculation and differential amplification of each output
To detect the irradiated position.
Dimensional wide range position detector. 2. Diffusion pattern of light beam (1) after transmission
Horizontal and vertical to the central axis (6) of the diffusion pattern
A transmission type diffusion plate (5) for diffusing two-dimensionally;
Captures the diffused light of light beam (1) diffused through diffuser (5)
Detector substrate with multiple optical detectors
(3a), wherein the light beam (1) is a laser beam
And modulated like LED, etc.
The substrate (3a) is parallel to the transmissive diffusion plate (5) and
Multiple detectors (4a) (4b) (4c) (4d)
Diodes at the four corners or at equal intervals on the cross
Two-dimensional diffusion by the photodiode.
Capturing light, two to three or more in order of power output
Select a little more, measure the relative output difference, and
Read the analog linearizer or the measured value directly into ROM
Correction calculation is performed by the correction means that replaces
Detect the irradiated position by differentially amplifying the force.
A two-dimensional wide-range position detector that emits.