RU2059228C1 - Device for defectoscopic checking of optically transparent crystals - Google Patents

Abstract

FIELD: optics. SUBSTANCE: light source 1 generates uniform light flux by means of optical system 2. The flux after it passed through crystal 12 is focused by optical system 3 and enters input of TV camera 4. Videosignal after passing differential unit 5 enters processing unit 6, where illuminance drops are calculated for different parts of crystal by means of units 7-10 by forming corresponding pulses. Value of drop is constant for fit specimens and stored in unit 11. Availability of a defect in crystal structure causes emergence of new additional drops in illuminances (pulses in counter), which drops permit to reject crystals. EFFECT: improved precision of inspection. 2 dwg

Description

 The invention relates to a control and measuring technique and can be used for inspection of optically transparent, for example watch, crystals.

A device containing light sources, an optical system and electronic processing units [1]
The disadvantage of this device is the low accuracy, since various defects in the crystals can be mutually compensated and will not affect the total light flux passing through the crystal or reflected from it.

 Closest to the invention is a device for electro-optical verification of products [2] containing a light source, an optical system, a photodetector, a television camera, a development device, in which each element of the photodetector produces a signal that is a function of the light emitted by the discrete region of the crystal, and the development device captures deviations of this signal from some basic one generated in one scan.

 The disadvantage of this device is the low accuracy of control of crystals having areas with unequal light transmission (holes, bevels, recesses), since in this case the basic signal for different sections of the crystal will be different.

 The objective of the invention is to increase the accuracy of control of crystals having areas with unequal light transmission.

 To do this, a comparison device, a counter, a digital comparator and a storage device are introduced into the device for inspection of optically transparent crystals, which contains series-connected light sources, an optical system, a television camera, a differentiating device, and an amplifier, and the amplifier output is connected to one of the inputs of the comparison device another input of which a reference voltage is connected, the output of the comparator is connected to the input of the counter, and the output of the counter is connected to one of the input s of a digital comparator, whose other input is connected to the output of the storage device.

 This makes it possible to generate a basic signal, not by the average value obtained by scanning the entire crystal, but by the number of drops of the illuminated different sections of the crystal, which is always the same for suitable samples and can be stored in advance. The presence of a defect in the crystal structure will lead to the appearance of "extra" differences in illumination (pulses in the counter), which allows the crystal to be rejected.

 This increases the accuracy of inspection of crystals with a complex surface configuration, and also increases the speed of inspection, since a defect can be detected in just one image scan.

 Figure 1 shows the structural diagram of the proposed device; in Fig.2 a sample of a crystal with defects and the corresponding signals for one scan line.

 The device consists of a light source 1, an optical system 3 and 2, a camera 4, a differentiation unit 5 and a signal processing device 6, consisting of a series-connected amplifier 7, a comparator 8, a counter 9, a digital comparator 10 and a storage device 11.

 In the control zone located between the optical systems 2 and 3, the controlled crystal 12 is supplied by the manipulator. The interconnections of the elements are shown in Fig. 1.

 The device operates as follows.

The light source 1 creates, using the optical system 2, a uniform light flux, which, passing through the crystal 12, is focused by the optical system 3 and fed to the input of the camera 4. The video signal (Fig.2 b), passing through the differentiation unit 5, is fed to the processing device 6 . The input signal of the processing device 6 is shown in FIG. 2 c. This signal is amplified by an amplifier 7 and fed to one input of the comparator 8, to the other input of which an exemplary voltage U _{arr is} applied (Fig. 2 g). Thus, at the output of the comparator 8 there will be pulses (Fig. 2 e) corresponding to the differences in the video signal, irrespective of the level of illumination of the surface of the crystal 12. These pulses arrive at counter 9, at the output of which a binary code corresponds to the number of pulses at the input. The binary code of the counter 9 is compared by a digital comparator 10 with the binary code of the storage device 11, where a binary code corresponding to a suitable crystal is recorded. If the binary code of the crystal under test exceeds the code of the suitable crystal, the digital comparator 10 gives a signal "marriage", otherwise the crystal is suitable.

 Using the proposed device in conjunction with a robot manipulator allows you to automate the control process of optically transparent crystals, to increase the accuracy and reliability of control crystals with a complex surface configuration.

Claims (1)

 DEVICE FOR DEFECTOSCOPIC CONTROL OF OPTICALLY TRANSPARENT CRYSTALS, comprising optically coupled light source and a video camera connected to a differentiation unit, the output of which is connected to an amplifier, characterized in that a comparison device, a counter, a digital comparator and a storage device are additionally introduced, the amplifier output being connected to one of the inputs of the comparator, the other input of which is connected to a reference voltage source, the output of the comparator is connected to the counter input a, a counter output is connected to one input of a digital comparator, the other input of which is connected to the output of the memory device.

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