JPS64657B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface defect inspection device for a three-dimensional object, and in particular, it
This invention relates to an optical system for detecting defects on the entire surface of the inspected part.

There is a strong demand for a device that detects surface defects on three-dimensional surfaces of small parts, such as electrical parts. For this purpose, an inspection machine as shown in FIGS. 1 and 2 has conventionally been used.

FIG. 1 shows a method in which light is scanned in the axial direction of the part to be inspected, and FIG. 2 shows a method in which light is scanned in the circumferential direction of the part to be inspected. That is, in FIGS. 1 and 2, 1 is the part to be inspected, 2 is the axial scanning light,
3 is a photoelectric element, and 4 is a circumferential direction scanning light.

In FIG. 1, light is scanned in the axial direction, and a photoelectric element 3 detects a change in reflected light due to a defect in a component 1 to be inspected.

Further, in FIG. 2, light is scanned in the circumferential direction of the part to be inspected 1, and the reflected light is received by the photoelectric element 3, so that defects can be extracted as in the case of FIG. 1.

However, in the cases of FIG. 1 and FIG. 2, the defect inspection is performed on the surface under the scanning line in only one direction, and when trying to inspect the entire surface of the inspected part 1,
In addition to requiring a mechanism to rotate the part to be inspected 1 in Fig. 1 and to move the part to be inspected 1 in the axial direction in Fig. 2, if the part to be inspected 1 is a small item, the number of processing speeds up. At present, the mechanism has become complicated, expensive, and impractical due to the necessity, the necessity to suppress vibration of the moving mechanism, the necessity to securely grip the component 1 to be inspected, and so on.

This invention was made to deal with the current situation, and by scanning the light three-dimensionally,
The present invention provides a surface defect inspection device that omits a mechanism for moving a component to be inspected. below,
The present invention will be explained based on the drawings.

Fig. 3 is a schematic configuration diagram of an optical system showing an embodiment of the present invention, Fig. 4 is a drive circuit diagram of a drive mirror in the optical system of Fig. 3, and Fig. 5 is a gain diagram in the drive circuit of Fig. 4. Output waveform diagram of control signal generator, No. 6
The figure is a schematic diagram showing the principle of three-dimensional inspection. For convenience of explanation, a case will be described in which a cylindrical inspected component 1 is inspected using a circular pattern.

3 to 6, 5 is a cylindrical internal reflecting mirror, 6a and 6b are drive mirrors, 7a and 7b are AGC (automatic gain control) circuits, 8a and 8b are drive circuits,
9 is a gain control signal generator, 10 is the output of the gain control signal generator 9, 11 and 12 are scanning optical paths, P,
Q are both ends of the component 1 to be inspected.

Next, the operation will be explained.

In FIG. 3, drive mirrors 6a and 6b are arranged so that their drive axes are perpendicular to each other, and more preferably, each
It is assumed that the motor is driven around each axis with drive waveforms of sinωt and cosωt. With such a configuration, the incident light is circularly scanned by the driving mirrors 6a and 6b, and after being reflected by the cylindrical internal reflecting mirror 5, the part to be inspected 1 is scanned in the circumferential direction.

In such a state, as shown in FIG. 4, the inputs sinωt,
Each of cosωt is input to AGC circuits 7a and 7b,
After each signal is multiplied by a gain of K times, it enters drive circuits 8a and 8b and is output as a signal for driving each drive mirror 6a and 6b.

Here, if the coefficient K multiplied by the AGC circuits 7a and 7b is changed by the gain control signal generator 9 as shown in FIG.
The outputs of a and 8b generate a sine wave and a cosine wave, respectively, whose maximum amplitude changes as shown in FIG. 5, and as a result, the maximum deflection angle of the drive mirrors 6a and 6b changes. This means that the drive mirrors 6a, 6b
This means that the diameter of the circular scanning pattern generated in

In FIG. 6, the scanning optical path along which the circular scanning pattern travels changes from 11 to 12 as described above. As a result, the circular scanning light reflected by the cylindrical internal reflecting mirror 5 is transmitted from point P to Q on the surface of the part to be inspected 1.
It will move to the point. Scanning optical path 11 to 12
It goes without saying that the position of the circular pattern that is reflected by the cylindrical internal reflecting mirror 5 and irradiates the part to be inspected 1 moves from point P to point Q as the part to be inspected moves. It is possible to perform three-dimensional scanning by moving the circumferential direction scanning light 4 in the axial direction while the inspection part 1 remains fixed, and it is possible to realize a surface defect inspection apparatus that does not require a mechanism for moving the inspection part 1. can.

Note that the means for receiving the reflected light from the component to be inspected 1 is not particularly limited, and depends on the purpose of inspection,
Any one can be used depending on the required sensitivity, response speed, etc. In addition, the part to be inspected 1 is assumed to be a cylinder, and the pattern for irradiating the part to be inspected 1 is as follows for convenience of explanation:
Although the explanation has been made using a circular pattern, it goes without saying that the same effect as described above can be obtained by matching the outer shape of the component 1 to be inspected with the pattern shape and changing the amplitude of the pattern.

Further, the cylindrical internal reflecting mirror 5 is connected to the scanning optical paths 11 and 1.
2, and it is also possible to replace it with an optical component that provides the same effect, such as a lens, a tapered cylindrical mirror, or a rotating surface mirror whose cross section is a quadratic curve. Furthermore, the control output for temporally changing the amplitude of the drive mirrors 6a, 6b is not limited to the shape shown in FIG. 5, but can be any function.

As explained in detail above, the present invention generates a similar pattern with increased amplitude while maintaining the shape of the two-dimensional scanning pattern generated by two driving mirrors, and irradiates it onto the inspected part using a light deflection means. As a result, the part to be inspected is three-dimensionally scanned, and a mechanism for moving the part to be inspected can be omitted, which provides great practical benefits.

[Brief explanation of drawings]

Fig. 1 is a schematic perspective view showing a conventional method of scanning light in the axial direction of a part to be inspected; Fig. 2 is a schematic perspective view showing a conventional method of scanning light in the circumferential direction of a part to be inspected; Fig. 3 is a schematic configuration diagram of an optical system showing an embodiment of the present invention, Fig. 4 is a drive circuit diagram of a drive mirror in the optical system of Fig. 3, and Fig. 5 is a gain control diagram in the drive circuit of Fig. 4. The output waveform diagram of the signal generator, FIG. 6, is a schematic diagram showing the principle of three-dimensional scanning. In the figure, 1 is a part to be inspected, 3 is a photoelectric element, 4 is a circumferential scanning light, 5 is a cylindrical internal reflecting mirror, 6a, 6
b is a driving mirror, 7a, 7b are AGC circuits, 8a, 8
b is a drive circuit, 9 is a gain control signal generator, 1
0 is an output, and 11 and 12 are scanning optical paths. In addition,
The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. In an apparatus that irradiates a part to be inspected with scanning light and detects surface defects of the part to be inspected by receiving reflection from the part to be inspected, the scanning light is irradiated with a scanning pattern similar to the external shape of the part to be inspected. A scanning means for scanning the part to be inspected, a means for temporally changing the size of the scanning pattern, and a tertiary light scanning means for irradiating the part to be inspected with the temporally changed scanning pattern. Features of surface defect inspection equipment.