JPH02259503A - Surface detector - Google Patents

Abstract

PURPOSE:To easily measure the fine ruggedness of the surface of a body to be measured without any complicate arithmetic by constituting a detector with the light receiving lens and the projection lens of columnar lens bodies which have respectively the same section continuously. CONSTITUTION:The light receiving lens 3 and projection lens 2B of the detector are formed of the columnar lens bodies which have respectively the same section continuously. Then the light from a semiconductor laser output part 1A is collimated by a collimator lens 1B into a parallel light beam, which is focused on the body A to be measured through a condenser lens 1C, a galvanomirror 2A, and the projection lens 2B. A light spot appearing on the body A to be measured is imaged on the light receiving surface of an optical position detecting element 4 through the light receiving lens part 3. The Z-directional positions + or -Xs of the imaged light beam correspond to the Z-directional positions + or -D in 1:1 proportion, so while a laser beam B is made to scan in a Y direction so that the moving speed of the light beam on the body A to be measured is constant, the Z-directional motion of the imaged light beam is measured to know the contour shape of the X-Z plane section of the surface of the body A.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a surface detection device, and in particular, it irradiates a measured object with spot light and scans it, and detects changes in the position of the reflected and scattered light by a photoelectric conversion element. The present invention relates to a surface detection device that measures minute irregularities, etc. on an object to be measured by detecting the same.

[Conventional technology]

Traditionally, surface inspection methods for parts and other members include:
There are 9 manual methods such as visual inspection, stylus method, and spot light method.

Of these, spot light is used, for example, as seen in Japanese Patent Application Laid-Open No. 59-92304, a laser spot is moved and irradiated onto the object surface via a variable angle mirror, and the moving reflected light is imaged on a body sensor. A relatively large number of devices are used to measure irregularities on the surface of an object.

[Problem to be solved by the invention]

However, among the above-mentioned conventional examples, visual inspection and stylus-based inspections not only require a lot of skill for inspection, but also take time to measure, and the judgment may differ depending on the measurer. There was an inconvenience that the test results varied.

In addition, in the surface unevenness measurement method using a variable angle mirror and a laser spot light, the three-dimensional position at the measurement point must be calculated from the mirror angle and the imaging position, which makes calculations complicated. However, there are disadvantages in that an expensive CCD element must be used as a position sensor, and that including its drive circuit increases the size of the entire device and complicates the entire system.

[Purpose of the invention]

An object of the present invention is to provide a surface inspection device that can overcome the disadvantages of the conventional example and can very easily measure minute irregularities on the surface of an object to be measured without performing particularly complicated calculations. There is a particular thing.

[Means to solve the problem]

The present invention includes a spot light output means, a light projecting lens means for irradiating the spot light output from the spot light output means onto a predetermined position on the object to be measured, and a light receiving lens section for directing the spot light on the object to be measured. and a light position detection element that receives light through the light source and converts it into a predetermined current value, and the light emitting lens means changes the angle of the spot light output from the spot light output means as necessary. It consists of a reflecting galvano mirror and a light projecting lens that irradiates the spot light sent through the galvano mirror onto the object to be measured. It adopts a structure in which it is formed by a columnar lens body. This aims to achieve the above-mentioned purpose.

[For production]

When moving the measurement point in the X direction, rotate the galvanometer mirror 2B. The laser beam passing through the second projection lens 2C is
Object to be measured A is moved in parallel in the X direction. Since the light reflected by the object to be measured becomes scattered light, it passes through the entire light receiving lens section 3.

At this time, the semiconductor device detection element 4 is
Orthogonal slit lights L□, Lll! + movement in the longitudinal direction, and there is no change on the element 4.

Further, when moving the measurement point in the X direction, the semiconductor laser output section IA, the first light projecting lens 2A, the receiving lens section 3.
The semiconductor device detection element 4 is set and moved. The galvanometer mirror 2B and the second projection lens 2C do not need to move in the X direction.

Furthermore, when measuring in the x and X directions, measurement can be performed by simply changing the angle of the galvanometer mirror 2B in the X direction, and by moving the galvanometer mirror 2B to the set semiconductor laser output section I in the X direction. In particular, movement in the X direction is easy and measurement time can be shortened. Furthermore, since the laser beam B is always irradiated perpendicularly to the measurement surface, the measurement accuracy is high.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

The embodiment shown in FIG. 1 includes a spot light output means 1,
A light projecting lens means 2 that irradiates the spot light outputted from the spot light output means 1 onto a predetermined position on the object A, and a light receiving lens section 3 that receives the spot light on the object A. It is equipped with an optical position detection element 4 that converts this into a predetermined current value.

Of these, the light projecting lens means 2 includes a galvano mirror 2A that reflects the spot light outputted from the spot light output means 1 by changing the angle as necessary, and this galvano mirror 2A.
The structure includes a light projection lens 2B that irradiates the object to be measured A with the spot light sent through the light source.

The light-receiving lens section 3 and the light-emitting lens 2B are formed by continuous columnar lens bodies having the same cross section.

In this embodiment, the spot light output means 1 includes a semiconductor laser output section IA, a collimator lens IB installed in the semiconductor laser output section IA, and a focusing lens IC installed on the output side of the collimator lens IB. It is configured. In this embodiment, the focusing lens IC is constituted by a columnar lens body having the same continuous cross section.

Due to the effects of the collimator lens IB and the focusing lens IC, the laser beam is outputted as appropriately focused parallel light.

The galvanometer mirror 2A is formed in a rectangular shape and can rotate around its longitudinal centerline as a central axis, and as shown in Fig. 1, the laser spot beams arriving from the y-axis direction are aligned in the same direction. The reflected output is directed downward in the figure, and the spot light on the object A to be measured can be moved back and forth along the y-axis.

Here, when the above-mentioned focusing lens IC is viewed along the propagation direction of the spot light, the central axis P of the columnar lens body is
1 are arranged so as to intersect the rotation center line of the galvanometer mirror 2A. Further, the light projecting lens 2B is arranged so that the center axis P of the columnar lens body is parallel to the rotation center line of the galvanometer mirror 2A.

Further, the light-receiving lens section 3 is arranged so that the central axis P3 of the columnar lens body is parallel to the y-axis in FIG.

As the optical position detection element 4, a semiconductor photoelectric conversion element formed in a rectangular shape is used in this embodiment.

The semiconductor photoelectric conversion element used as the optical position detection element 4 outputs a photocurrent IA or ■S of a larger absolute value from one or the other end as the irradiated spot light deviates from the center point. It has this characteristic.

Here, the operation of the apparatus shown in FIG. 1 will be explained based on FIGS. 1 and 2.

The light emitted from the semiconductor laser output section IA is turned into a parallel beam by the collimator lens IB, passes through the condenser lens IC, is reflected by the galvanometer mirror 2A, and further passes through the projection lens 2B to be focused on the object to be measured A. In this case, since the focusing lens IC and the light projecting lens 2B are both constituted by a columnar lens body with the same continuous cross section, the galvano mirror can be used regardless of the position of the incident light from the light projecting lens IA in the X direction. By changing the reflection angle of 2A, the laser beam B is translated in the y direction shown in FIGS. 1 and 2. In other words, the laser beam B can scan the object A to be measured in the y direction by adjusting the angle of the galvanometer mirror 2A.

The light spot S thus appearing on the object to be measured A is imaged by the light receiving lens section 3 onto the light receiving surface of the optical position detection element 4.

In this case, since the light-receiving lens section 3 is formed by a continuous columnar lens body with the same lens cross section as described above, the image formed is not a point but the thick line L in FIG.
It is a thick line as shown in SI+L sz. Therefore, the installation of the optical position detection element 4 becomes extremely easy.
Furthermore, even if the laser beam B is moved (scanned) in the y direction,
A part of the image is always placed on the -dimensional optical position detection element 4. Therefore, the position of the imaged light beam in two directions ±x3 is the position of ±D in two directions as shown in FIG.
There is a one-to-one correspondence between the laser beam B and the object to be measured A.
By measuring the movement of the imaged light beam in two directions while scanning in the y direction so that the moving speed of the upper light beam is constant, the contour shape in the yz plane cross section of the surface of the object A can be determined. can be known.

The position of the imaging light beam on the optical position detection element 4 is determined by the two photocurrents Ik, 1. Than,
It can be calculated using the following formula.

xs /L= (1,-IA)/(1,+IA)
L indicates 1/2 of the entire length of the optical position detection element.

Here, the contour shape of the object to be measured A in the r)'-ZJ section and the value of X3 obtained in time series while scanning the laser beam B are in a proportional relationship as described above.

On the other hand, from the angle control of the galvano mirror 2A scanning the laser beam B and the photocurrents IA and Is,
, is performed by the arithmetic circuit shown in FIG.

That is, in the arithmetic circuit shown in FIG. 3, the photocurrent IA,
1. is converted into voltage by the IV converter 11.12, amplified by the amplifier circuit 13.14, detected at the timing of laser drive, and then added (Is + IA)
and subtraction (I++ Ia) processing.

Here, reference numeral 15 indicates a laser drive circuit, 16 indicates a timing output circuit, and 17 and 18 indicate a detection circuit.

Further, reference numeral 19A indicates an addition circuit, and reference numeral 19B indicates a subtraction circuit.

The outputs from the addition circuit 18 and the subtraction circuit 19 are sent to the division circuit 2.
1, where '(Is Ia)/(Ii' is calculated. The result of this calculation is converted into a signal by the A-D converter 22, and then sent to the microcomputer 25. This microcomputer 25 has a function of driving and controlling the circuit shown in FIG. 3 as well as other related components described later.

The calculation results by the microcomputer 25A are stored in the memory 26 and sent to an overall control computer (not shown). It is also output as a drive signal for the galvano mirror 2A.

Reference numeral 27 indicates a digital-to-analog conversion circuit, 28 indicates a buffer, and 29 indicates a memory.

Next, an application example of the above embodiment is shown in FIGS. 4 and 5.

The application examples shown in Figures 4 and 5 are intended to improve the quality of the product.
, for determining "defective", and the embodiment shown in FIGS. 1 and 2 is used as a sensing section for this purpose.

That is, the application example shown in FIG. 4 is composed of a control computer section 30, and a sensing section 31 and a peripheral mechanism section 32 that operate under the control of the control computer section 3o.

The sensing section 31 is composed of a sensor head mechanism 31A formed substantially in the same manner as in FIG. 1, and a sensor controller 31B that drives the sensor head mechanism 31A.

The peripheral mechanism section 32 includes a movable stage 1 32A on which an object to be measured (inspection object) A is installed, and a head position adjustment mechanism 32B that adjusts the overall position of the sensor head mechanism 31A described above.
It is composed of

Further, the control computer section 30 includes a main control section 30A,
The configuration includes a display section 30B, an input section 30C, and the like.

The apparatus shown in FIG. 4 operates according to the procedure shown in the flowchart shown in FIG.

That is, first, the object to be inspected as the object to be measured A is received, and after alignment, the sensing section 31 is activated and the object to be inspected is delivered to an external device. By repeating the measurement of the contour shape on the Y-Z plane cross section of the surface of the object to be measured while changing the position of the piezo stage in the X direction, the three-dimensional shape of the surface of the object to be measured can be obtained as a set of two-dimensional contour shapes. can.

The three-dimensional shape data of the surface of the measurement object obtained here is calculated and processed in the computer of the control computer section.
Two-dimensional parameters such as average roughness, maximum height, maximum depth, and frequency distribution are extracted.

These are compared with predetermined reference parameter values to determine whether the product is defective or non-defective. And the judgment result is
It is the object to be measured.

In this way, in this embodiment, a triangulation method is applied in which a columnar lens is used for the light-receiving lens section 3 and a one-dimensional semiconductor photodetector is used as the optical position detection element, so there is no need for complicated calculations. Three-dimensional shape data can be obtained directly, the circuit system can be configured simply because the image processing method does not use a CCD, and since it is a non-contact inspection using a laser, it is possible to It has the advantage of not causing scratches.

Furthermore, in the application examples shown in Figures 4 and 5,
Since the criteria for determining defects is quantified, there are no variations in quality, and by going online with the production line, time costs can also be reduced. Furthermore, since it is a judgment software based on secondary parameters, it has the advantage that it can be applied to other measuring objects by changing the parameters.

〔Effect of the invention〕

As described above, according to the present invention, since a columnar lens body in which the same lens cross section is continuous is used as a projection lens, even if the position of the projection spot light is changed by rotation of the galvanomirror, the same parallel For example, the light beam can be moved in parallel in the y direction, and therefore, even when the light source of the spot light and the object to be measured are fixed, it is possible to move and scan the object to be measured with the spot light. The measurement accuracy can be significantly improved, and even if the spot light output means is moved along the projection lens, it is possible to irradiate the object to be measured with the spot light under exactly the same conditions. The three-dimensional shape of a point can be obtained very easily, and since the light-receiving lens is made of the same columnar lens body as the light-emitting lens, the output light of the light-receiving lens can be made into a line. It is possible to provide an unprecedented and excellent surface detection device in which the detection element can be equipped and maintained very easily.

Fig. 1 is a schematic configuration diagram showing an embodiment of the present invention, Fig. 2 is an explanatory diagram showing the operation of Fig. 1, and Fig. 3 shows an example of signal processing for the photocurrent obtained in Fig. 2. The block circuit diagrams of FIGS. 4 and 5 are explanatory diagrams showing an application example of FIG. 1.

DESCRIPTION OF SYMBOLS 1...Spot light output means, 2...Light projection lens means, 2A...Galvano mirror 12B...Light projection lens,
3... Light receiving lens section.

Applicant: Suzuki Motor Co., Ltd.

Claims (1)

[Claims] (1) a spot light output means, a light projection lens means for irradiating the spot light outputted from the spot light output means onto a predetermined position on the object to be measured, and a light receiving lens section for directing the spot light on the object to be measured; and a light position detection element that receives light through the light source and converts it into a predetermined current value, and the light projecting lens means changes the angle of the spot light output from the spot light output means as necessary. It consists of a reflecting galvano mirror and a light projecting lens that irradiates the spot light sent through the galvano mirror onto the object to be measured, and the light receiving lens and the light projecting lens each have the same continuous cross section. A surface detection device comprising a columnar lens body.