JPS61160005A - Optical position-height distribution detector - Google Patents

Abstract

PURPOSE:To reduce dimensions of an apparatus by eliminating a video-signal processing circuit, by installing light-spot scanning means for a specimen, semiconductor position detecting element for position deviation of the light-spot, and distribution detecting means for position-height distribution of a specimen surface. CONSTITUTION:A beam of light irradiating onto a specimen S intersects its reflected beam through on angle of theta. An optical scanner 4 swings a mirror 5 by magnetic excitation of a drive coil 6 with an oscillator 7 and the reflected beam also and thus, a light-spot P on the surface of the specimen S is scanned in the Y-direction. Deviation of a position of a light-spot P' irradiated onto a detecting surface 10a of a semiconductor position detecting element 10 in the X-direction changes an output voltage Vx. A compensating circuit 11 has been introduced into an output voltage Ey of the oscillator 7 and output voltage Vx of the semiconductor position detecting element 10 for comparing one with the other. Light-spots P'1, P'2 created by the specimen surface S1 and reflection by a surface higher than this surface by a indicate a position difference of b on the surface 10a and as height a and position difference b have a relation as shown by the equation, the position difference b can be obtained by setting the angle theta constant.

Description

Detailed Description of the Invention "Field of Industrial Application" This invention relates to an optical position-height distribution detection bag F that optically detects the position-height distribution of a surface to be measured. It is useful as a position sensor for robots.

"Prior Art and Problems" Conventional devices of this type utilize the fact that when a linear light line is irradiated onto the surface of the object to be measured, the light line image is distorted according to changes in the height of the surface ( The so-called photosection method) is also commonly used for eel.

However, such conventional devices use ITV (industrial television) or C0D (charge-coupled device) as a means for detecting optical line images, which requires a video signal processing circuit. There are problems in that it is large, complex, expensive, and takes a long time to process data.

[Object of the Invention] An object of the present invention is to provide an optical position-height distribution detection device that can be constructed in a small size, easily, and inexpensively, and can shorten data processing time.

"Structure of the Invention" The optical position-height distribution detection device of the present invention includes a light spot scanning means for scanning a measurement target with a light spot, and a detection surface that receives a light spot reflected from the measurement target and scans the measurement target. The position W of the light spot in the cross direction that intersects the direction
It is configured to include a semiconductor position detecting element for detecting position A and a distribution detecting means for detecting the position-height distribution of the surface of the object to be measured based on the scanning position of the light spot and the positional displacement in the intersecting direction.

In the above configuration, the optical spot scanning means is a means for mechanically or electrically scanning the optical spot, and a conventionally known optical scanner, for example, can be used.

In the structure shown in F, the semiconductor device detection element is a non-divided type sensor for detecting the position of a light spot whose detection surface is integrally continuous, and a commercially available PSD can be used.

In the configuration described above, the distribution detection means may be configured in hardware using a comparator circuit or the like, or may be configured in software using a microcombiner or the like.

U Embodiment The present invention will be further explained in detail below based on the embodiment shown in the drawings. Here, Fig. 1 is an explanatory diagram of the configuration of one embodiment of the optical type (presence-height distribution detection device) of this invention, Fig. 2 is an explanatory diagram of reflection of a light spot, and Fig. 3 is an illustration of scanning of a light spot and a semiconductor device. This is an explanatory diagram for explaining the output signal of the device detection element.
) is a perspective view of the surface of the measurement target, (b) is a plan view of the detection surface of the semiconductor position detection element, (C) is a graph showing the relationship between scanning position and time, and (d) is the output of the semiconductor device detection element. It is a graph showing changes in a signal over time. Note that this invention is not limited to this.

The light emitted from the semiconductor laser element 2 in the optical position-height distribution detection bag ffl shown in FIG. be done.

The reflected light of the optical spot P reflected on the surface of the Ijll constant object S is incident on the detection surface 101 of the semiconductor device detection element 10 via the lens 8 and the interference filter 9.

As shown in FIG. 1, the angle between the light incident on the measurement object S and the reflected light is θ, and the plane formed by the incident light and the reflected light is oriented in the X-axis direction.

The optical scanner 4 causes the mirror 5 to swing by exciting the drive coil 6 with an oscillator 7. Due to this swing, the light beam reflected by the mirror 5 also swings, and as a result, the light spot P on the surface of the measurement object S is scanned in the X-axis direction.

The semiconductor device detection element 10 is a sensor for detecting the position of a light spot using a silicon photodiode, and is, for example, a PSD manufactured by Hamamatsu Television Co., Ltd. There are 2fl for -dimensional position detection and 2fll for two-dimensional position detection, but either of them may be used.

Here, a type for -dimensional position detection is used, and when the position of the light spot P' incident on the detection surface 10a is displaced in the X-axis direction, the output voltage vX changes.

That is, the detection surface 10. An output voltage vX is output according to the position of the upper optical spot P' in the X-axis direction.

The comparator circuit 11 compares the output voltage E of the initiation device 7 with the semiconductor (0
, the output voltage vx of the N detection element lO is manually set,
I am comparing these.

Now, FIG. 2 shows the detection plane ion at the position of the light spot P,' reflected on one measurement target surface Sl and the position of the light spot P2' reflected on the measurement target surface S2, which is higher than the measurement target surface S by an amount a. It is a diagram showing the position on the top. This position difference is a shift in the X-axis direction, and has the following relational expression.

b-2ajan(θ/2) Here, if θ is constant, it can be seen that the value of the position difference is proportional to the height a.

As shown in FIG. 1, it is assumed that there is a step extending in the X-axis direction on the surface of the measurement pair g/LS. Specifically, this can be assumed to be two iron plates stacked one on top of the other.

When the light spot P is scanned by the optical scanner 4, its locus becomes as shown by the broken line shown in FIG. 3(a). When the light spot P is scanned in this way, the trajectory of the light spot P' on the detection surface 10m of the semiconductor device detection element IO is ll
5a as shown by the broken line shown in FIG. 5(b). If the surface of the measurement object S is a smooth plane, the IIIL trace of the light spot P' on the detection surface 10a will be 1 m vertically, but here, on the surface of the Ij+1 constant objects S, , S2 with steps, Because it is reflected, it becomes a key-shaped trajectory with steps. This step is the difference in position.

The voltages F, y outputted from the lifting device 7 to the comparison circuit 11 represent the oscillation of the mirror 5, that is, they represent the scanning position of the optical stub 7)P. It also represents the scanning position of the optical spot P' on the detection surface lO□, and is a voltage signal that oscillates regularly over time as shown in FIG. 3(C). In other words, by this output voltage E, the Y of the optical spot P is
The axial position will be known.

On the other hand, as shown in FIG. 3(d), the output voltage (■) of the semiconductor device detection element 10. is Vx2 when the light spot P is on the higher surface of the measurement target S2, and the light spot P is Vx2.
When P is on the surface of the lower measurement target S1, Vxl
become. The difference vI between these Vx2 and Vxl is the difference between the step roof l
b is a voltage proportional to the surface height of the measurement object S, , S2.

The comparison circuit 11 detects the position of the optical sub-board I-P in the Y-axis direction from the output voltage V of the oscillation device 7, and detects the height of the surface of the object to be measured from the output voltage VX of the semiconductor {1γ position detection element 10. , by comparing these, the measurement targets S1 and S2
The location of the step in the Y-axis direction is detected.

Therefore, the output voltage E of the transmitter 7 and the semiconductor (ff, N
If the output voltage vx of the detecting element 10 is selected to a value that is consistent with the output voltage vx, and if the light beam is scanned along the Y-axis by (p) and moved along the If the step is at a constant position, the output voltage VJ of the comparator circuit 11 is a constant value, but if the step is displaced in the Y-axis direction, the output voltage VJ will change by a voltage corresponding to the displacement.

If this output voltage V- is used, for example, to control an industrial robot, the wrist of the industrial robot can be moved along a step. Specifically, this can be suitably used for sealing work on automobile bodies.

As another example, a PSD for two-dimensional position detection is used as the semiconductor device detection element, and the output voltage V on the Y axis is changed to the output voltage Ey of the oscillation device 7 and inputted to the comparison circuit 11. It will be done.

In this case, since the output voltage Vy for the Y-axis directly indicates the position in the Y-axis direction, the position of the step can be directly detected without intervening a time element.

"Effects of the Invention" According to the present invention, there is provided a light spot scanning means for scanning a measurement target with a light spot, a light spot reflected from the measurement target is received by a detection surface, and the light spot is scanned in a cross direction intersecting the scanning direction. It is equipped with a semiconductor device detection element that detects the positional displacement of the optical boat/board, and a distribution detection means that detects the position-height distribution of the surface of the measurement target based on the scanning position of the optical spot and the positional displacement in the cross direction. An optical position-height distribution detection device is provided, which has a simple configuration such as no need for a video signal processing circuit, and is small and inexpensive. It also speeds up processing. Furthermore, since the light source is a spot, there is also the advantage of saving power.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the configuration of an embodiment of the optical position-height distribution detection device of the present invention, Fig. 2 is an explanatory diagram of reflection of a light spot, and Fig. 3 is an illustration of scanning of a light spot and a semiconductor device detection element. (a) is a perspective view of the surface of the measurement target, (b) is a plan view of the detection surface of the semiconductor device detection element, and (C) shows the relationship between scanning position and time. Graph (d) is a graph showing changes over time in the output signal of the semiconductor device detection element. (Explanation of symbols) 1... Optical position-height distribution detection device 2... Semiconductor laser element 4... Optical scanner 5... Mirror 7... Oscillator IO
...Semiconductor device detection element 101...Detection surface 11.
... Comparison circuit P, P'... Light spots s, S,, S2... Measurement target. (a) Figure 3 (C)

Claims (1)

[Claims] 1. A light spot scanning means for scanning the measurement target with a light spot; a semiconductor that receives the light spot reflected from the measurement target on a detection surface and detects the positional displacement of the light spot in a cross direction that intersects the scanning direction; An optical position system characterized by comprising a position detection element and a distribution detection means for detecting a position-height distribution of a surface to be measured based on a scanning position of a light spot and a positional displacement in the intersecting direction.
Height distribution detection device.