JPS61105407A - Length detecting device - Google Patents

Abstract

PURPOSE:To measure the length and external appearance of an object to be detected at the same time by projecting light on the object to be detected and detecting the position of a light spot by a one-dimensional optical sensor and scanning an end of the object to be detected in a flying spot system. CONSTITUTION:The light of a laser pipe 1 is reflected on a vibrating mirror 2 and made incident on a beam splitter 10. The light irradiating the object 6 to be detected and the light directed to the one-dimensional semiconductor position sensor 12 are splitted by the splitter 10. Further, the arrangement is made so that the longitudinal direction of the sensor 12 coincides with the scanning direction of an optical beam from the beam splitter 10 and output voltages X1, X2 are generated in proportion to the position projected on the sensor 12 of the optical beam. The voltages X1, X2 are inputted to an arithmetic circuit 19 via arithmetic circuits 17, 18 respectively. On the other hand, the transmitted light of the object 6 to be detected is photoelectrically converted 15 and compared with the reference voltage by a comparator 21 and a 0.1 signal is inputted to a computing element 26. Then, the length of the object to be detected is detected by the output of the circuit 19. Further, the external appearance is detected from the output from a photoelectric element 15 by a comparator 27. Accordingly, since the length is detected by the output of the one-dimensional optical sensor, the length and external appearance can be detected at the same time.

Description

[Detailed Description of the Invention] [Industrial Application Fields] This invention uses a flying spot method to determine the appearance of an object and the size of the object. The present invention relates to an inspection device that simultaneously detects oxidation.

[Following Comparison Technique] FIGS. 3, 4, and 5 are system NIJ diagrams of a conventional laser complete visual inspection system. HeNe laser tube 1
The laser beam that exits is reflected by the vibrating mirror 2, and the laser beam
1 reflected light is converted into a parallel scanning beam by 5 and irradiated onto the object to be inspected (for example, a cylindrical roller) 6.
The light is collected by the photoelectric conversion element 8, and photoelectric conversion is performed. The amplifier 9 is for amplifying the electrical signal, and its typical signal waveform is as shown in FIG. The dark area is created by the fact that when the laser spot deviates from the object 6, there is no reflected light.

In addition, the gate convexity in the bright area shows various waveforms depending on the processing condition of the surface of the test object 6, but if there is a defect on the inspection surface, the amount of reflected light at that part will decrease and a pulse-like defect waveform will occur. The above-mentioned measurement system is used for visual inspection. The vibration lPJ+ end of the vibrating mirror 2 is detected by the electromagnetic induction coil 2', and the pulse generator 3 outputs a pulse having a period proportional to the vibration period of the vibrating mirror 2.

However, this conventional measurement system was only able to perform a visual inspection of the object to be inspected.

Therefore, in order to measure dimensions such as the length of the object, a separate length measuring device must be used in a separate process, making the length measuring work complicated and inefficient.

[Object of the Invention] This invention was made to solve the above-mentioned problems, and an object thereof is to provide an apparatus that can perform an external appearance inspection and a length measurement of an object to be inspected using the same apparatus.

[IPI part of the invention] The length detection device of the present invention uses a flying spot method to project light onto an object to be inspected, and uses a one-dimensional optical sensor to detect the position of the optical stub, so that the light spot is aligned with the object to be inspected. The length of the object to be inspected is calculated from the one-dimensional optical sensor output when scanning the edge of the object.

[Example J This invention will be described below with reference to one embodiment.

Note that in FIGS. 1 and 2, the same numbers as in FIG. 3 are given the same numbers.

1 and 2, a beam splitter 10 is provided between the vibrating mirror 2 and the object 6, and the vibrating mirror 2
The light from the 6-dimensional 1' conductor position sensor 12 is directed to the test object 6 and the other through the imaging lens 11 to the -dimensional semiconductor device sensor 12. is arranged so as to coincide with the scanning direction of the potential beam projected from the beam splitter 10. Output voltages X1 and X2 are generated at the output terminals 12m and 12b of the sensor 12, which are proportional to the position where the beam is projected onto the sensor 12.

The output terminals 12a, 12b of the sensor 12 are connected to amplifiers 13, 13', respectively, and the output terminals of the amplifiers 1:'(, 13' are connected to arithmetic circuits 17, 18 as shown in I. The arithmetic circuit 18 is connected to a zero arithmetic circuit 19 that calculates X1+X2.The output terminal of the arithmetic circuit 19 is connected to an analog-to-digital converter (referred to as an A/D converter) 20. There is.

On the other hand, a charging converter 15 is provided to receive transmitted light from the object 6 through a condensing lens 14, and the output of this charging converter 15 is applied to an amplifier 1G.

The output of the amplifier 16 is applied to the comparator 21, and the output of the amplifier 16
The comparator 21 is configured so that the output becomes 1 when the output exceeds the reference voltage ■, and as a result, the comparator 21 outputs "0" when the light beam enters the test object side from one end of the test object 6. from a1
1'' when exiting from the other end of the test object 6 to the outside.
An output that changes from "0" to "0" is generated.

One output of the comparator 21 is applied to the differentiating circuit 22,
Here, the rising edge of the output of the comparator 21 is detected, and now 1
One is applied to the differentiating circuit 24 via the inverting circuit 23, where the fall of the output of the comparator 21 is detected.

The output of each differentiating circuit 22 and 24 is an ordate 25, respectively.
It is applied as a start signal to the A/D converter 20 via the A/D converter 20.

26 is a combinator which calculates the length of the object to be inspected from the output voltage of the A/D converter 20 using a formula described later.

In the above configuration, the beam splitter 10
The separated scanning laser beam is focused on the position sensor 12 by an imaging lens.The output of the 0 position sensor 12 is amplified by an amplifier 13.13', and becomes outputs Xi and X'l.

The laser light that is irradiated onto the object 6 and transmitted without being blocked by the object 6 is focused by the lens 14, guided to the photoelectric converter 15, and subjected to photoelectric conversion. The output signal is inverted and amplified by an amplifier 16 and compared with V by a comparator 21, and a pulse having a length corresponding to the length of the object to be inspected is output.

- The two outputs Xi and X2 on the dimensional position sensor 12 are an arithmetic circuit 17 for obtaining only the likely spot position, regardless of the light intensity. IF3. ．． 3 Passes through Xl and is input. The output of the arithmetic circuit 19 represents the position of the laser spot on the object 6 to be inspected. Therefore, at the appropriate time, A/
When D-converted, the converted digital output represents the position of the laser likely spot at that point in time. After passing, the differentiator 24 detects the fall time of the pulse, and the 8/D converter 20
The start timing is given, the conversion result is input to the micro combinator 26, and the length is determined by the following equation.

For example, if the conversion output of the A/D converter 20 at the rising edge of the pulse is Dl, and the conversion output at the falling edge of the pulse is D2, then the following expression can be written as micro・Turn on the combiator 261.

Here, K is the imaging magnification of the lens 11 and the amplifier 13°13
This value is determined by the amplification factor of the input circuit 17, 18, and 19 of the circuit 17, 18, and 19, and the data can be given to the combination 1-1 in advance.

Note that the visual inspection of the test object 6 can be obtained by amplifying the output of the charging conversion element 8 with an amplifier 9 and comparing it with a comparator 27.

[Effects of the Invention 1] As detailed above, the present invention projects light onto a test object using a flying spot method, detects the position of the light spot using a one-dimensional optical sensor, and detects the position of the light spot on the test object. Since the length of the object to be inspected is calculated from the one-dimensional optical sensor output when the edge is scanned, the length of the object to be inspected can be performed with the same equipment as well as the visual inspection. Appearance inspection work can be performed with high efficiency.

[Brief explanation of drawings]

The first group is a diagram showing an optical system of an embodiment of this invention, FIG. 2 is a block diagram of an embodiment of this invention, FIG. 3 is a diagram showing an example of an optical system of a conventional device, and FIG. 4 is a plan view of the main part of FIG. 1, and FIG. ff15 is an output waveform diagram of the main part of the device shown in FIG. 1I'3. 1... Laser tube, 6... Test object, 12...
-Dimension sensor, 1), 18.19...Light reduction circuit, 20
... A/D converter, 21... Comparator, 22.24.
...Differential circuit, 26...Microcomputer.

Claims (1)

[Claims] (1) In addition to projecting light onto the test object using the flying spot method, the position of the light spot is detected using a one-dimensional optical sensor, and the one-dimensional optical sensor output is obtained when the light spot scans the edge of the test object. A length detection device characterized in that it calculates the length of an object to be inspected.