JP2738859B2 - Edge detection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an end detection device that optically scans an end of a test object and detects the end including the end thereof. The present invention relates to an improvement in an end detection device that can accurately detect the end of a test object even when the end has a defect such as a burr, dust, or a flaw.

(Prior Art) Conventionally, an end detection device as shown schematically in FIGS. 6 and 7 has been known. This end detection device guides a thin laser beam P emitted from a laser light source 1 as a light source unit to a pentaprism 2, and the pentaprism 2 allows a work (eg,
The laser beam P is deflected in a direction in which a PC plate or the like 3 punched by a press is present, and the pentaprism 2 is rotated in one direction about an axis J, so that the work 3 is optically moved by the scanning beam P '. And the detector 5 receives the scanning beam P ′ transmitted through the hole 4 penetrated through the work 3, and inputs the received light output signal S to the CPU 6, so that the hole is formed in the work 3. The end portions 4a, 4b, etc. of the 4 (for example, the outer shape, hole diameter, hole pitch, etc. of the PC board) are detected.

For example, when the scanning beam P 'is scanned in parallel with the rectangular hole 4 when the hole 4 is rectangular, the light receiving output signal S rises at the edge 4d and the light receiving output signal S rises at the edge 4c. Falling, rising of this light receiving output signal S,
By evaluating the fall using the CPU 6, the end 4a,
4b is being detected.

6 and 7, reference numeral 7 denotes an fθ lens, 8
Is a telecentric lens, 9 is a condenser lens, arrow F indicates the scanning direction of the scanning beam P ', and the scanning pitch is about 0.2 mm.

(Problems to be Solved by the Invention) By the way, at the end of the test object, scratches and burrs may be generated during processing, and foreign matter such as dust may be attached. If the test object is optically scanned as it is, the received light output signal S output from the detector 5 becomes an irregular pulse signal near the end of the test object.
Since the light reception output signal S frequently rises and falls, and the end point of the pulse change is unknown, it is necessary to identify whether the light reception output signal S can be used for evaluation as it is. Difficult, light receiving output signal S obtained for each scan over the entire scanning area
The data is taken into U6, the light reception output signal S obtained for each scan is compared with each other as data, and it is determined whether or not the light reception output signal S can be used for evaluation of edge detection.

However, in such a conventional edge detection device,
Since the received light output signal S must be stored, the memory becomes enormous, and the end detection processing must be performed after the completion of the scanning of the entire area of the hole 4 to be scanned. This has the disadvantage of being far from real-time processing.

In addition, if there are many light reception output signals S that cannot be used for evaluation among the obtained light reception output signals S, there is a problem that the detection accuracy of the end portion is reduced.

Further, if there is too much data to store, the memory overflows.

Therefore, an object of the present invention is to provide an edge detection device that can accurately detect the edge of a test object by real-time processing even when there is an edge defect such as dust, scratches, and burrs. It is in.

(Means for Solving the Problems) The edge detection device according to the present invention is characterized by a light source unit that emits a narrow beam, and a scanning unit that optically scans a test object including the end by the beam. And a light receiving unit that receives the beam through the test object, and outputs a light receiving output signal that changes in a pulsed manner due to an end surface defect such as a burr, dust, and a flaw, and a light receiving output signal of the light receiving unit. A first counting section that counts and accumulates the number of changes between high and low; a delay section that delays a light receiving output signal of the light receiving section; and a delay light receiving output signal that is delayed by the delay section. A second counting section that counts and accumulates the number of changes between high and low of the delayed light receiving output signal; and a comparing section that compares each of the accumulated values obtained by each of the counting sections. And based on the result of the comparison by the comparison unit, Edge determination for detecting the end of the pulse-like change after the pulse-like change has occurred due to the end face defect such as burrs, dust, and scratches of the received light output signal, and determining the end of the test object. And a department.

(Operation) According to the present invention, a pulsed light receiving output signal is delayed to generate a delayed light receiving output signal, and the number of pulse changes between the light receiving output signal and the delayed light receiving signal is counted and compared. Since the end point of the pulse-like change is determined after the pulse-like change occurs due to the end face defect such as burrs, dust, scratches, etc. of the received light output signal, the end of the test object can be easily and in real time. Part detection can be performed.

(Embodiment) Hereinafter, an embodiment of an edge detection device according to the present invention will be described with reference to the drawings.

In FIG. 4, reference numeral 10 denotes a test object, and reference numeral 11 denotes a rectangular hole formed in the test object. Around the end of the hole 11, a burr 12 generated during processing adheres. The specimen 10
Is the scanning beam P 'shown in FIGS. 6 and 7 as in the prior art.
, And a light receiving output signal S is output from the detector 5 as in the conventional case. FIG. 4 shows a case where the scanning beam P 'scans a very small portion of the end 11a of the hole 11 and a case where the center of the hole 11 is scanned. Letter S ₁ designates shown in FIG. 2 the ends
Shows the light reception output signal obtained by the scanning the grazing locations 11a, letter S ₂ designates shown in FIG. 3 shows a light reception output signal obtained by scanning the central portion of the hole 11.

When scanning the grazing point end 11a, the scanning beam P 'is because it is blocked each time across a portion where burrs 12 are out tight, light reception output signals S ₁ resulting from edge 11b to edge 11c When the pulse signal becomes irregular over the entire area and the center of the hole 11 is scanned, the edge 11b and the edge 11c
Since blocked by tension began to have burrs 12, the light reception output signal S ₂ obtained becomes irregular pulse in the vicinity of the edge 11b, 11c, maintaining a high at an intermediate portion between the edge 11b and the edge 11c To be a rectangular signal.

The light receiving output signals S ₁ and S ₂ are input to a retrigger timer 13 and a delay timer 14, respectively, as shown in FIG. 1, and the retrigger timer 13 outputs the light receiving output signals S ₁ and S ₂
Continue to be set consists change or high from low to high from low to high by the pulse changes based on changes to low, the output K is from high to low after a time setting T _0. The delay timer 14 has a function as a delay unit that delays the received light output signals S ₁ and S ₂ by the delay time T ₁ ,
Scanning the grazing point end 11a, as shown in FIG. 2, the delay time T ₁ delayed delayed light reception output signal
S ₁ is output from the delay timer 14, when scanning the central portion of the hole 11, as shown in FIG. 3, the delay time T ₁ delayed by the delay light reception output signal S ₂ 'is output from the delay timer 14 . The delay time T ₁ is substantially equal to or slightly greater to the set time T _0. That is, the set time T ₀
Slightly smaller or equal to the delay time T _1.

The output K of the retrigger timer 13 and the light receiving output signals S ₁ and S ₂
The output of the AND circuit 15 is the input terminal Cu of the counter circuit 16.
Is input to In the case where scanning is being performed on a very small portion of the end 11a, the retrigger timer 13 continues to be triggered,
Since retrigger the timer 13 maintains a high during the final pulse (n-th pulse) setting time from the time entered T ₀ of the light reception output signals S _1, the output K of the retrigger the timer 13
Is the set time T ₀ from the time when the “n” th pulse is output
Between, i.e., it remains high between the time when the 1st pulse of the light reception output signals S ₁ is input in time T _2, then becomes low. Therefore, the AND circuit 15 during the time the output K is at a high T _2, the pulse change in the light reception output signals S ₁ every time the light reception output signals S ₁ is varied in a pulsed manner as the first counting unit It is passed toward the counter circuit 16.

On the other hand, when the scanning of the central portion of the bore 11, in the vicinity of the edge 11b, burrs 12 are generated, retrigger the timer 13, several pulses of the light reception output signals S _2, for example, receiving the output signal continues to be triggered by five pulses of S _2, as shown in Figure 3, is maintained high for a set time T ₀ from the time when the 5 th pulse of the received light output signal S ₂ is input, the consisting of high and low after the set time T ₀ elapses. And, between the edge 11b and the edge 11c, the light receiving output signal S ₂ is remains high, there is no change, the output K of the retrigger the timer 13 remains low. When the vicinity of the edge 11c is scanned again, since light-reception output signal S ₂ is pulsed, the output K of the retrigger the timer 13 is made low and high, continue to be triggered each time a change of the light reception output signal S ₂ , for example, between the time when the 4 th pulse of light reception output signal S ₂ is input time T _0, remains high, then
Go low. Therefore, the AND circuit 15 during the time the output K is at a high T _2, will be passed towards the light reception output signal S ₂ to the counter circuit 16 each time the light reception output signal S ₂ is inputted.

Therefore, the counter circuit 16 accumulates and counts the number of changes from the rising to the falling or the pulse-like changes from the falling to the rising of the light receiving output signals S ₁ and S ₂ . The delayed light receiving output signals S ₁ ′ and S ₂ ′
The signal is input to an input terminal Cu of a counter circuit 17 as a counting unit, and is also input to an input terminal D of a flip-flop 18 for detecting an end. The details of the flip-flop 18 will be described later. Counter circuit 17 receives light output signal
S ₁ ', S _2' are counted total number of pulses changes from change or fall from the rise to fall to rise. The output of the counter circuit 16 is
The input is input to the input terminal A of the comparison circuit 22, and the output of the counter circuit 17 is input to the input terminal B of the comparison circuit 22. The counter circuits 16 and 17 are reset by a power reset signal via OR circuits 19 and 20 or a differential output of a differentiating circuit 21 to be described later, and the count contents are cleared each time power is input or scanning is performed.

The comparison circuit 22 constitutes a part of an end determination unit that determines the end of the test object.The comparison circuit 22 determines whether the count number of the counter circuit 16 matches the count number of the counter circuit 17. 22, the output terminal A = B changes from low to high, and the match signal H changes from the output terminal A = B to the flip-flop.
The signal is output toward the 23 reset terminals R. The output of the first terminal of the counter circuit 17 is input to the set terminal S of the flip-flop 23. When the first terminal of the counter circuit 17 becomes high, as shown in FIGS. ,
Output G output from output terminal Q of flip-flop 23
Changes from low to high and the coincidence signal H of the comparison circuit 22 changes from high to low, the output G output from the output terminal Q of the flip-flop 23 changes from high to low.

That is, when the grazing point of the end portion 11a is scanned by the first pulse delayed light reception output signals S ₁ flip flop 23 is set, the n-th delayed light reception output signals S ₁ ' since will be reset by the pulse, the output G from the output terminal Q of the flip-flop 23, as shown in FIG. 2, the delay receiving the output signal S ₁ '
Remain high during the pulsating transition of. In contrast, hole 11
When the central portion is scanned and the vicinity of the edge 11b is scanned, the flip-flop 23 is set by the first first pulse of the received light output signal S ₂ ′, 'because it is reset by the 5 th pulse of the output G of the output terminal Q of the flip-flop 23, as shown in FIG. 3, the delay receiving the output signal S _2' signal S ₂ first from 1st 5 It stays high for the time before the th pulse is generated and then goes low. Also, edge 11
When scanning near c, the flip-flop 23 is set by the first pulse at the end of the light receiving output signal S ₂ ′ and reset by the fourth pulse, so that the output of the flip-flop 23 is output. The output G of the terminal Q is
It stays high for a period of time from when the first to fourth pulses of the delayed light receiving output signal S ₂ ′ are generated, and then goes low.

The output G of the flip-flop 23 is input to the differentiating circuit 21 and the input terminal T of the flip-flop 18. This flip-flop 18 has a counter circuit at its set terminal S.
When the first terminal of the counter circuit 17 is connected and the first terminal of the counter circuit 17 goes high, the output I of the output terminal Q of the flip-flop 18 is set high, and the input to the input terminal T goes from high to low. When it changes, the delayed light receiving output signal S ₁ ′,
Provided that S ₂ ′ is low, the output I of output terminal Q of the flip-flop 18 changes from high to low,
When the delayed light output signals S ₁ ′ and S ₂ ′ are high,
The output I of the output terminal Q of the flip-flop 18 keeps high, and the delayed light receiving output signal as shown in FIG.
When S ₁ ′ is input, the flip-flop 18 is set high by the output of the first terminal of the counter 17 and the output G of the flip-flop 23 becomes the delayed light receiving output signal.
Since maintaining a high over the entire output period of S ₁ ', the output I of the flip-flop 18 remains high, the output G of the flip-flop 23 falls from high to low, the flip-flop 18 is reset Therefore, the output I of the output terminal Q of the flip-flop 18 changes from high to low similarly to the output G.

On the other hand, as shown in FIG.
When S ₂ 'is input, the output I of the output terminal Q of the flip-flop 18 is set high by the output of the first terminal of the counter 17, while the output G of the flip-flop 23 is set.
Changes from low to high and from high to low with the first pulse change of the delayed received light output signal S ₂ ′,
Even if the output G changes in this manner, the delayed light receiving output signal S ₂ ′ remains high after the time when the output G falls, so that the output I of the output terminal Q of the flip-flop 18 is output.
Remains high after the fifth pulse of the first pulsed change of the delayed received light output signal S ₂ ′ has been counted, and the end of the delayed received light output signal S ₂ ′ When the output G changes from low to high again and changes from high to low due to the pulse change of the output signal I, the output I becomes the fourth pulse change of the end of the delayed light output signal S ₂ ′.
Since the pulse is low after the generation of the second pulse, the pulse changes from high to low.

Therefore, no matter how the form of the pulse-like change of the light-receiving output signal S changes, the shaped end detection signal is output as the output I from the output terminal Q of the flip-flop 18.

In addition, in accordance with the above embodiment, the one that receives the scanning beam P ′ transmitted through the hole 11 by the detector 5 was used.
One that receives the scanning beam P ′ reflected by the work 3 can be used.

Further, in the embodiment, each time the retrigger timer 13 times up, the counter circuits 16 and 17 are reset by the differential output of the differentiating circuit 21, and the light receiving output signals S ₁ and S ₂ that change in a pulsed manner, the delayed light receiving output signal The pulse change of S ₁ ′ and S ₂ ′ is counted.
Reference numeral 17 denotes light receiving output signals S ₁ and S ₂ , delayed light receiving output signals S ₁ ′ and S ₂ ′
May be configured to count the total number of such pulse-like changes.

Further, as shown in FIG. 5, it is possible to detect the end 11a of the circular hole 11 penetrating through the work 10.

(Effect of the Invention) Since the edge detection device according to the present invention is configured as described above, even if there is an edge defect such as dust, scratches, burrs, etc., the edge of the test object can be detected by real-time processing. There is an effect that the part can be accurately detected.

In particular, even if the received light output signal irregularly changes in a pulse manner in the vicinity of the edge and the edge, there is an effect that the edge and the edge can be accurately determined.

Further, since the end portion can be accurately detected without using a large capacity device such as a CPU and a memory, the effect of reducing costs can be achieved.

Further, since the received light output signal obtained by the scan of the edge portion can also be used for the evaluation of the edge portion, the effect that the accuracy is improved as compared with the related art is produced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a main part circuit of an end detection device according to the present invention, FIGS. 2 and 3 are timing charts for explaining the main part circuit, and FIG. FIG. 5 is a view showing an example of an object to be scanned, FIG. 5 is a view showing another example of the object to be scanned by the end detection device, FIG. 6 and FIG. FIG. REFERENCE SIGNS LIST 1 laser light source (light source unit) 2 pentaprism (scanning unit) 13 retrigger timer 14 delay timer (delay unit) 16 counter circuit (first counting unit) 17 counter circuit (second counting unit) 22 comparator circuit (end determination section) 23, 24 ... flip-flop circuits S _1, S ₂ ... light reception output signals S ₁ ', S _2' ... delayed light reception output signal P ... beam

Claims (1)

(57) [Claims] A light source section for emitting a narrow beam; a scanning section for optically scanning an object including its end with the beam; a light receiving section for receiving the beam via the object; ,garbage,
A light-receiving unit that outputs a light-receiving output signal that changes in a pulsed manner due to an end surface defect such as a flaw; and a first unit that counts and accumulates the number of changes between high and low of the light-receiving output signal of the light-receiving unit. A counting section, a delay section for delaying a light receiving output signal of the light receiving section, and a delayed light receiving output signal delayed by the delay section being inputted, and a change between a high and a low of the delayed light receiving output signal. A second counting unit that counts and accumulates the counts; and a comparing unit that compares each of the accumulated values obtained by each of the counting units. Based on a result of the comparison by the comparing units, the light receiving output signal has burrs and dust. An end determining unit that detects an end point of the pulse-like change after the pulse-like change occurs due to a defect of the end surface such as a scratch and determines an end of the test object. An end detection device, characterized in that: