JP2003194515A - Displacement measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the reliability of displacement data and luminance data by converting displacement data and luminance data which have become undefined-value data in accordance with alarm data. <P>SOLUTION: A displacement measuring instrument receives the reflected light from the irradiated position of an object W to be measured when light is projected upon the object W from a light projecting section 2 by means of a light receiving section 6, and measures the displacement of the irradiated position in a non-contacting state from measured signals obtained based on the light receiving position of the light receiving section 6. An arithmetic processing section 15 calculates the displacement data Z and luminance data G about the irradiated position from the measured signals. A dark alarm output section 24 outputs a dark alarm warning that the displacement data Z about the irradiated position are undefined-value data Z' when the level of light quantity is lower than a prescribed level. When the dark alarm is outputted, a data converting section 19 converts the undefined-value displacement data Z' into a prescribed first specific value. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to a light receiving section which receives light emitted from a light projecting section toward a measuring object and reflected at an irradiation position of the measuring object, and from a measurement signal output from the light receiving section to the irradiation position. The present invention relates to a displacement measuring device that measures displacement of an irradiation position by obtaining displacement data of

[0002]

2. Description of the Related Art FIG. 9 is a schematic view showing a conventional displacement measuring device 50. In the displacement measuring device 50, the laser light emitted from the light projecting unit 51 is reflected by the measurement target W, and the reflected laser light is received by the PSD 52 and photoelectrically converted. Then, based on the light receiving position on the PSD 52, the PSD 52
Outputs a pair of current signals. The pair of current signals is
The voltage signals are amplified by the I / V converters 53 and 53, and then digitized by the A / D converters 54 and 54. The digital signals are input to the subtractor 55 and the adder 56, respectively, and are subjected to addition / subtraction calculation. The subtraction data and the addition data are input to the divider 57, and the division data is output as displacement data. This displacement data is output as the displacement of the position on the measurement target W irradiated with the laser light. Thereby, the displacement of the measuring object W is measured in a non-contact manner.

The current amount of the pair of current signals is PSD.
Since it is proportional to the amount of light received on 52, the added data of the pair of digital signals becomes the brightness data, and the brightness of the measuring object W can be measured.

However, in the object W to be measured, for example, solder formed by densely gathering a large number of solder ball particles, the reflection angle of the laser beam reflected by the solder ball depends on the incident angle of the laser beam on the spherical surface. There is a case where a part of the reflected laser light is not received by the PSD 52 because it is different from the normal reflection angle. For this reason, the amount of light received by the PSD 52 decreases, the addition data output from the adder 56 also has a small value, accurate displacement data is not output, and unreliable indefinite value data occurs. is there.

Further, the amount of light received by the PSD 52 is different for each measuring object W depending on the reflectance of the measuring object W, so that the amount of light received by the PSD 52 is reduced and the adder 56 outputs the same as above. There is a problem that the added data that is output also has a small value, accurate displacement data is not output, and the data becomes unreliable indefinite value data.

On the other hand, in the I / V converters 53 and 53, a process of switching the gain of the I / V converters 53 and 53 is executed by automatic gain control according to the amount of current from the PSD. That is, the S / N ratio is improved by adjusting the brightness data obtained by increasing the gain when the current amount is small and decreasing the gain when the current amount is large.

Here, when the laser beam is scanned from the low luminance region of the measuring object W to the high luminance region, the amount of current, which is the amount of received light, increases significantly. However, the I / V converter 53 by the above-mentioned automatic gain control,
The gain switching process of 53 cannot follow the increase / decrease of the current amount at the same time, and a large amount of light is detected while the gain is increased at the boundary where the laser light moves to a region with high brightness. Therefore, the A / D converters 54, 54 in the subsequent stage are in a saturated state, and a correct digital output cannot be obtained in a high-luminance region, resulting in undefined data.

Further, when the displacement data is calculated based on such indefinite value data, the displacement data also becomes indefinite value data, and the unreliable displacement data is erroneously output.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems of the prior art, and its purpose is to provide displacement data that has become indefinite value data according to alarm data. It is intended to improve the reliability of the displacement data and the brightness data by converting the brightness data and the brightness data.

In particular, when a dark alarm is output, by ignoring or level converting the indefinite value displacement data,
The purpose of this is to improve the reliability of displacement data by excluding displacement from being measured. Further, when a dark alarm is output, the indefinite value displacement data of the irradiation position is converted into the displacement data in the vicinity of the irradiation position to improve the reliability of the displacement data.

Further, when a bright alarm is output, by ignoring the indefinite value displacement data and emphasizing the indefinite value luminance data, a tracking error of the gain switching process of the I / V converter with respect to the increase / decrease in the received light amount. To improve the reliability of the brightness data and displacement data obtained from the measurement target.

[0012]

A means for solving the above-mentioned problems will be described with reference to the accompanying drawings. The displacement measuring device according to claim 1 is a measuring object (W) from a light projecting section (2).
The light received by the light receiving section (6) is reflected by the light receiving section (6), and the displacement data (Z) of the irradiation position is obtained from the measurement signal output by the light receiving section. A displacement measuring device for measuring displacement of an irradiation position, comprising an A / D converter (1) for A / D converting the measurement signal.
2) and an alarm output section (16) for outputting alarm data based on the signal output from the A / D conversion section.
And a data conversion unit (19) for invalidating the displacement data corresponding to the output alarm data based on the displacement data near the irradiation position when the alarm data is output. It is characterized by

A displacement measuring apparatus according to a second aspect is the displacement measuring apparatus according to the first aspect, wherein the alarm output section is provided when a signal output from the A / D conversion section is less than a predetermined value. , A dark alarm that warns that the displacement data in the vicinity of the irradiation position is indefinite value displacement data (Z ') is output, and the data conversion unit outputs the indefinite value displacement data when the dark alarm is output. Is characterized by ignoring or leveling.

In the displacement measuring device according to a third aspect, the light receiving section (6) receives the light emitted from the light projecting section (2) toward the measurement object (W) and reflected at the irradiation position of the measurement object. ,
A displacement measuring device for measuring displacement of the irradiation position by obtaining displacement data (Z) and brightness data (G) of the irradiation position from a measurement signal output from the light receiving unit, wherein the measurement signal is A / When the A / D conversion unit (12) for D conversion and the A / D conversion unit are in a saturated state, the displacement data and the luminance data are indefinite value displacement data (Z ′) and indefinite value luminance data, respectively. A bright alarm output unit (25) that warns that it is (G ′), and a data conversion unit (19) that ignores the indefinite value displacement data and emphasizes the indefinite value luminance data when the bright alarm is output. ), And are provided.

Light received by the light projecting unit 2 toward the measuring object W and reflected at the irradiation position of the measuring object W is received by the light receiving unit 6. From the measurement signal obtained based on the light receiving position of the light receiving unit 6, the displacement data Z and the brightness data G of the irradiation position are calculated.

Alarm data is output from the alarm output section 16 based on the light intensity level of the measurement signal. The displacement data Z, the brightness data G, and the alarm data at the same irradiation position are synchronized based on the position information. Displacement data Z
Alternatively, the brightness data G is converted according to the alarm data.

The alarm data includes a dark alarm that is output when the light amount level is less than a predetermined value or a bright alarm that is output when the light amount level is more than the predetermined value.

Depending on the reflectance and the shape of the irradiation position of the object W to be measured, the light amount level in the light receiving section 6 decreases and becomes less than a predetermined value, and a dark alarm is output. Data converter 1
The reference numeral 9 designates the displacement position data Z of the irradiation position when the dark alarm is output, for example, the invalid displacement data Z such that the displacement data Z is excluded from the displacement extraction target at the subsequent image processing.
_It is converted to ₀ (for example, “0” at 256 gradations). Thus, the image processing by excluding the invalid displacement data Z ₀ displacement data Z is to become a feasible, not be affected by the invalid displacement data Z _0, thereby improving the reliability of the displacement data Z.

Further, the displacement data Z of the irradiation position can be converted into the displacement data Z near (for example, around) the irradiation position. As a result, the influence of the indefinite value displacement data is reduced and the reliability of the displacement data Z is improved.

Further, the measurement object W (for example, a printed circuit board)
When the laser beam is scanned from a region (for example, a resist or a printed circuit board surface) having a low reflectance at the irradiation position of 1 to a region (for example, a reference mark), the gain of the I / V conversion unit 11 cannot follow the measurement. The light amount level of the signal becomes a predetermined value or more and is input to the A / D conversion unit 12. This gives A /
The D conversion unit 12 overflows and becomes saturated. The alarm output unit 16 detects the saturation state of the A / D conversion unit 12 and outputs a bright alarm. Data converter 19
When the bright alarm is output, the displacement data Z of the irradiation position is set to a predetermined second prescribed value, for example, the displacement data Z that is surely invalidated by the image processing unit 32 in the subsequent stage (for example, 256). It is converted into "0") by gradation. Also,
The brightness data G of the irradiation position is set to a predetermined third specified value, for example,
The image processing unit 32 in the subsequent stage performs emphasis conversion to luminance data G (for example, "255" full scale with 256 gradations) that is surely validated.

As a result, the data displayed by the converted displacement data Z and brightness data G becomes data equivalent to the displacement data Z and brightness data G of the reference mark M, and the displacement data Z and brightness data G at the irradiation position. Improves reliability.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION As a measurement object W of the displacement measuring apparatus 10, there is a printed circuit board P on which electronic parts such as QFP and BGA are mounted as shown in FIG. A resist R is applied to the surface of the printed circuit board P. A foot pattern is formed on the resist R at the position where the terminal of the electronic component is located, and the solder H is printed in advance on the pattern.

On the other hand, on a pair of diagonals of the printed circuit board P,
A reference mark M is provided. The reference mark M
Is a mark indicating the origin position that serves as a reference for the coordinate position of the solder H or the like printed at the position where the electronic component is mounted on the printed circuit board P, and accurately detects the existence of the reference mark M and its position. As a result, the electronic component can be accurately mounted at a predetermined position on the printed board P. As the material of the reference mark M, a material such as gold plating or solder plating having a high gloss may be used, and in this case, the reflectance is significantly higher than that of the resist R or the solder H applied to the printed board P. Because of its high brightness, the brightness is high.
Since it is formed very thin on the top, the displacement is low, which is almost the same as the displacement of the resist R.

Although the printed circuit board surface Pa, the resist R, and the reference mark M have some displacement, they are binarized by the image processing means 32, which will be described later, to obtain displacement data Z.
It becomes “0”, and is treated as the reference plane data S having no displacement as shown in FIG.

FIG. 2 is a schematic diagram showing the measuring sensor 1.
The measurement sensor 1 is substantially composed of a light projecting section 2 and a light receiving section 6. The light projecting unit 2 is a scanning type light projecting unit including a laser light source 3, a scanning unit 4 having a built-in polygon mirror and a light projecting lens 5, and a laser emitted from the laser light source 3 and scanned by rotation of the polygon mirror. The light is collimated by the light projecting lens 5, and scans the measurement target W.

The light receiving section 6 includes a light receiving lens 7 and an image forming lens 8.
The laser light reflected from the object W to be measured is imaged as a single light spot on the light receiving element 9 by the imaging lens 8 via the light receiving lens 7. The light spot follows the scanning of the laser light of the light projecting unit 2 and the light receiving element 9
Move up.

The light receiving element 9 is made of PSD, and photoelectrically converts the amount of light received by the light spot into a pair of current signals based on the image formation position of the light spot, and outputs the current signal. Each of the pair of current signals is a signal that is inversely proportional to the distance to the terminal provided in the direction orthogonal to the moving direction of the light spot.

FIG. 3 is a schematic block diagram showing an embodiment of the displacement measuring device 10 according to the present invention. The displacement measuring device 10 includes a connector (not shown) provided on the board C and an I
The / V conversion unit 11, the A / D conversion unit 12, the CPU 13, and the storage unit 14 are substantially configured.

The measuring sensor 1 is connected to the displacement measuring device 10 via a connector. On the other hand, the board C is inserted into the PCI card slot of the general-purpose personal computer 30 and
It is connected to the personal computer 30 via a bus.

As shown in FIG. 3, the measurement sensor 1
Has a scanning start means 4a. The scanning start means 4a is
For example, it is a slit that blocks the laser light, and outputs a scanning start signal for detecting the presence or absence of the laser light cutoff to a counter 28 described later.

The I / V converter 11 converts the current signal output from the PSD 9 into a voltage signal. I / V converter 11
With the automatic gain control, the gain of the I / V converter can be switched according to the amount of current from the PSD 9. That is, when the amount of current is small, the gain is increased,
Further, when the amount of current is large, the gain is lowered and the brightness data G described later is adjusted to improve the S / N ratio.

The A / D converter 12 converts the voltage signal converted by the I / V converter 11 into a digital signal. A /
The D conversion unit 12 has a saturation detection function of detecting whether or not an overflow (saturation state) occurs due to the input measurement signal. When saturated, the A / D converter 12
Is a saturation signal (1-bit information) to the alarm output unit 16.
Is output.

The CPU 13 comprises, for example, a program-writable FPGA, and has an arithmetic processing unit 15, an alarm output unit 16, a position information calculation unit 17, and a synchronization unit 18.
And the data conversion unit 19 are functionally expressed.

The arithmetic processing section 15 includes a subtracting section 21 and an adding section 2.
2 and the division unit 23. The subtraction unit 21 subtracts the pair of digital signals A and B and outputs subtraction data (AB) to the division unit 23. The adder 22 adds a pair of digital signals A and B and adds the added data (A + B) to the divider 2
Output to 3.

The division unit 23 divides the subtraction data (A-B) by the addition data (A + B) to obtain displacement data Z (Z = (A
-B) / (A + B)) is output to the synchronization unit 18. The addition data (A + B) is the brightness data G, which is output to the synchronization unit 18. The displacement data Z is, for example, 8
It has the information amount of bit, and the displacement (height) of the measuring object W is 2
It can be identified by 56 gradations. Similarly, the brightness data G
For example, it has an information amount of 8 bits and the brightness of the measurement target W is 2
It can be identified by 56 gradations.

The alarm output section 16 includes a dark alarm output section 24, a bright alarm output section 25, and an OR circuit 26.
Composed of. A predetermined threshold is set in the dark alarm output unit 24. The dark alarm output unit 24
When it is determined that the brightness data G, which is the addition data (A + B) from the addition unit 22, is less than this threshold value, the displacement data Z is determined to be indefinite value data, and a dark alarm is output. That is, this threshold value is the lower limit value of the luminance data G necessary for measuring the displacement data Z.

Further, the bright alarm output section 25 is
The saturation signal output when the A / D conversion unit 12 is saturated is detected from the voltage signal input to the / D conversion unit 12. When the input of the saturation signal is received, the A / D conversion unit 12 determines that it is in the saturated state and outputs a bright alarm.
The saturation signal may be generated by the A / D conversion unit 12 itself by detecting the saturation state, or may be saturated when the level of the input signal or the output signal of the A / D conversion unit 12 exceeds a predetermined value. You may make it output, recognizing that it is a state.

Both the dark alarm and the bright alarm are binary information of 1 bit. The OR circuit 26 outputs the alarm data to the synchronization unit 18 when either the dark alarm or the bright alarm is input.

The position information calculation unit 17 is a clock generation unit 27.
And a counter 28, which counts a fixed clock starting from a start signal from the scanning start means 4a and calculates position data (count signal) of the irradiation position of the measurement object W.

The synchronization unit 18 is provided with an address conversion table, and converts the position data (count signal) output from the counter 28 into address data corresponding to the address area of the storage unit 14. In addition, the synchronization unit 18
Synchronizes with the address data of the irradiation position by adjusting the delay time in the process of processing the displacement data Z, the brightness data G and the alarm data of a certain irradiation position.

The data conversion section 19 refers to the displacement data Z, the brightness data G and the alarm data which are synchronized with the address data, and converts the displacement data Z or the brightness data G according to the input alarm data.

For example, when a dark alarm is output, the indefinite value displacement data Z '(see FIG. 6 (b)) synchronized with the dark alarm is used as a predetermined first prescribed value, for example, "256 gradation". It is converted to 0 ″ and used as invalid displacement data Z ₀ (see FIG. 6C). Further, when the bright alarm is output, the indefinite value displacement data Z ′ synchronized with the bright alarm is set to a predetermined second prescribed value, for example, 256.
Convert to gradation "0". Similarly, the indefinite value brightness data G ′ is set to a predetermined third specified value, for example, “25 of 256 gradations”
Convert to 5 "full scale.

The storage unit 14 is composed of, for example, a memory having a relatively small capacity, and temporarily holds the displacement data Z and the brightness data G after data conversion according to the address data. When the held data amount reaches a predetermined amount, the data held in the storage unit described later is transferred.

The personal computer 30 into which the board C is inserted is provided with an image processing means 32 and a storage means 31. The image processing means 32 is an image processing program installed in the personal computer 30. The storage unit 31 is a large-capacity memory such as an HDD of the personal computer 30. The display unit 33 is composed of, for example, a liquid crystal display or the like. Then, the displacement data Z and the brightness data G temporarily stored in the storage unit 14 of the board C are input to the storage unit 31 via the PCI bus at any time, and a measurement image is formed.
The measurement image can be displayed by the image processing means 32 and the display means 33.

The image processing means 32 has a binarization processing function, and includes the printed circuit board surface Pa, the resist R,
As shown in FIG. 1B, the displacement data Z having a low value with respect to the solder H or the like, which is a displacement detection target of the reference mark M, is collectively binarized with a binarization threshold value for the displacement of a predetermined reference plane S. Is set to "0" to obtain the reference plane data S having no displacement. Similarly, as shown in FIG. 1C, the luminance data G having a low value with respect to the reference mark M or the like whose luminance is to be detected, such as the printed circuit board surface Pa, the resist R, and the solder H, has a predetermined reference plane S. This is a binarization threshold value for the received light amount of, and is collectively set to "0" to obtain reference plane data S having no displacement.

The operation of this embodiment will be described. First, the case where the solder H on the printed board P as the measurement target W is scanned by the laser light will be described with reference to the flowchart of FIG. Since the reference mark M is not scanned, the bright alarm is not output (“0” in FIG. 5).

The measuring object W is scanned with laser light for measurement. The scanning start signal is output to the counter 28, and the address data is output to the synchronization unit 18. The laser light scans the solder H on the printed circuit board P (ST1), and the reflected laser light is received by the PSD 9 (ST2). The measurement signal from the PSD 9 is arithmetically processed by the arithmetic processing unit 15, and the displacement data Z and the luminance data G are output to the synchronization unit 18 (S
T3). Normally, the addition data (A + B) (luminance data G) output from the addition unit 22 is the dark alarm output unit 2
Since it is determined to be equal to or larger than the predetermined threshold value in step 4 (ST4-N
O), the dark alarm is not output. Then, the displacement data Z and the brightness data G of the irradiation position are synchronized with the address data of the irradiation position (ST5).

On the other hand, if the reflected light path of the reflected laser light changes due to the shape of the irradiation position of the solder H scanned by the laser, the light receiving level of the laser light received by the PSD 9 decreases. Accordingly, when the dark alarm output unit 24 determines that the addition data (A + B) output from the addition unit 22 is less than the predetermined threshold value (ST4-YES), the displacement data Z and the brightness calculated by the calculation processing unit 15 are calculated. Data G
Is determined to be indefinite value data, and the dark alarm output unit 24
Outputs a dark alarm to the synchronization unit 18 (ST
6). Then, the displacement data Z, the brightness data G and the dark alarm of the irradiation position are synchronized with the address data of the irradiation position (ST5).

As shown in FIG. 5, the synchronized data is transferred to the data conversion section 19 in the structure of displacement data Z, luminance data G, and alarm data, and is 1 when the image processing means 32 performs image processing. It becomes data for pixels.

When the data conversion section 19 determines that there is no dark alarm ("0") as shown in FIG. 5 (ST7-NO), the data conversion is not executed and the data conversion is performed as shown in FIG. ), The image processing means 32 develops an image (ST8). Since the displacement data Z in the expanded image data does not include a dark alarm, the indefinite value displacement data Z ′ does not occur and the data becomes highly reliable.

When the data conversion section 19 determines that a dark alarm is present as shown in FIG. 5 (ST
7-YES), the synchronized indefinite value displacement data Z ′ is
In order to make the displacement data Z substantially equal to the reference plane data S of the resist R or the printed circuit board surface Pa, that is, the invalid displacement data Z ₀ , it is converted to a predetermined first prescribed value, for example, “0” of 256 gradations. (ST9).

An image is developed by the image processing means 32 based on the data-converted displacement data Z (ST8).
Here, the image-developed solder H in FIG. 6 will be described. This solder H is composed of 3 × 5 pixels.

The solder image of FIG. 6A is as described above.
It is an image when it is determined that there is no dark alarm. FIG. 6B is an image of the solder H when data is not converted by the data conversion unit 19 as in the conventional case. Solder H
Due to the shape and the like, the three pieces of pixel data are the indefinite value displacement data Z ′, that is, the pixel data in which the dark alarm occurs. If this pixel data is adopted, an error will occur in displacement and position. Therefore, it is necessary to detect the indefinite value displacement data Z ′ after image development. If these are converted into “0” of 256 gradations in the data conversion unit 19 in advance, in the developed solder image, as shown in FIG. Z ′ is used as invalid displacement data Z ₀ of displacement “0”.

As described above, by converting the individual displacement data Z in advance, the process of detecting the indefinite value displacement data Z'by the image processing by the image processing means 32 on the side of the personal computer 30 in the subsequent stage is omitted. be able to. As a result, it becomes possible to extract only the displacement above the reference plane S, for example, only the solder H, and the takt time is improved.

Next, the operation when the reference mark M on the printed circuit board P as the measurement object W is scanned by the laser beam will be described with reference to the flowchart of FIG. In addition,
Since the resist R, the printed circuit board surface Pa, and the reference mark M are scanned, the dark alarm is not output.

The object W to be measured is scanned with laser light for measurement. The scanning start signal is output to the counter 28, and the address data is output to the synchronization unit 18. First, the resist R and the printed circuit board surface Pa are scanned with laser light (ST1).
1). The reflected laser light is received by the PSD 9 (ST
12). The measurement signal from the PSD 9 is arithmetically processed by the arithmetic processing unit 15, and the displacement data Z and the luminance data G are output to the synchronization unit 18 (ST13). Since the resist R and the printed circuit board surface Pa have low reflectance with respect to the reference mark M, the A / D converter 12 does not overflow due to the input measurement signal, and the bright alarm is not output (S).
T14-NO). Then, the displacement data Z of the irradiation position
And the brightness data G are synchronized with the address data of the irradiation position (ST15).

On the other hand, when the laser light is scanned from the surface Pa of the printed board onto the reference mark M, the light receiving level rises sharply. Therefore, the gain switching process by the automatic gain control of the I / V conversion unit 11 cannot follow, and the gain increases at the boundary of the reference mark M when the laser beam is scanned from the printed circuit board surface Pa to the reference mark M. In this state, the voltage signal is output to the A / D converter 12.

When this voltage signal is input, the A / D conversion unit 12 is saturated (ST14-YES), and the saturation signal is output to the bright alarm output unit 25. The bright alarm output unit 25 determines that it is in a saturated state by the input of the saturation signal and outputs a bright alarm to the synchronization unit 18 (ST16). Then, the displacement data Z of the irradiation position, the brightness data G and the bright alarm are synchronized with the address data of the irradiation position (ST15).

When the data conversion section 19 determines that there is no bright alarm (ST17-NO), the data conversion is not executed as shown in FIG. 5, and the image processing means 32 develops the image ( ST18). As shown in FIG. 8B, since the developed image data does not include a bright alarm, the contour of the reference mark M becomes the brightness data G in which the contour is clearly detected, which is highly reliable data. .

When the data converter 19 determines that there is a bright alarm (ST17-YES),
Since the A / D converter 12 is in a saturated state, an incorrect digital signal is output, and the actual displacement of the irradiation position shown in FIG. 1 (a) and the arithmetic processing shown in FIG. 1 (b). Part 15
Different from the displacement data Z calculated in
May cause a portion (indefinite value displacement data Z ′ shown in FIG. 1B) that is equal to or larger than the binarization threshold for calculating the reference plane S in the image processing unit 32 in the subsequent stage. Therefore, in the data conversion unit 19, the dotted line in FIG.
As shown in, the synchronized indefinite value displacement data Z ′ is
The displacement data Z that becomes invalid after the binarization processing by the image processing means 32, that is, the predetermined second prescribed value 2
It is converted into "0" of 56 gradations (ST19).

On the other hand, the luminance data G is also shown in FIG.
The actual brightness at the irradiation position shown in (a) is different from the brightness data G calculated by the calculation processing section 15 shown in FIG. 1 (c). At this time, if image processing is executed without data conversion, as shown in FIG. 8A, the gain switching process by the automatic gain control of the I / V conversion unit 11 cannot be followed, and the laser light is reflected on the surface of the printed circuit board. The brightness data G at the boundary of the reference mark M when scanned from Pa to the reference mark M becomes indefinite value brightness data G ′.

Therefore, this indefinite value brightness data G'is
As shown by the dotted line in FIG. 1C and FIG. 8B, the luminance data G that becomes effective after the binarization processing by the image processing unit 32, that is, 256 as a predetermined third prescribed value.
Converts to "255" full scale of gradation.

As a result, the indeterminate brightness data G ′ is not truncated by the binarization process in the image processing means 32 in the subsequent stage, and the contour of the reference mark M can be accurately extracted. Further, as a result, the formation position of the reference mark M can be accurately detected, and the solder H printed on the printed board P with the formation position of the reference mark M as the coordinate origin.
It becomes possible to accurately detect coordinate positions such as.

Further, in the above-described embodiment, when the dark alarm is output, the indefinite value displacement data Z'is converted into the predetermined first specified value.
As shown in (d), when a dark alarm is output instead of this data conversion, the displacement data Z of the irradiation position is output.
May be converted into displacement data Z in the vicinity of the irradiation position, for example, in the surroundings. If the displacement data Z is selected from the displacement data Z of the eight pixels around the irradiation position, the displacement data Z at that irradiation position is comparable to the displacement data Z, so it can be estimated as the true value of the displacement data Z at the irradiation position. It is also possible to improve the reliability of the.

In the above embodiment, the board C is used.
The displacement measuring device 10 mounted on the above is the CPU 1
The program of No. 3 may be written in the memory of the personal computer 30 in advance, and the I / V conversion unit 11 and the A / D conversion unit 12 may be provided on the connector side connected to the measurement sensor 1.

[0066]

As described above, in the displacement measuring device according to the present invention, the reliability of the displacement data and the luminance data can be improved by converting the displacement data and the luminance data which have become indefinite value data according to the alarm data. There is an effect. Since this processing is executed before the image processing, it is not necessary to detect the indefinite value data after the image is developed by the image processing, and the takt time of the displacement measurement can be improved.

In particular, when a dark alarm is output, the displacement data is converted into a predetermined first specified value before image processing in advance, so that displacement is not extracted during image processing.
The reliability of the displacement data Z can be improved. Also, when a dark alarm is output, by converting the indefinite value displacement data of the irradiation position into displacement data Z around the irradiation position,
There is an effect that the displacement data can be estimated and the reliability of the displacement data can be improved.

Further, when a bright alarm is output, the indefinite value displacement data is converted into a predetermined second prescribed value, and the indefinite value luminance data is converted into a prescribed third prescribed value,
There is an effect that the tracking error of the gain switching process of the I / V converter with respect to the increase / decrease in the amount of received light can be corrected and the reliability of the brightness data G and the displacement data obtained from the measurement object can be improved.

[Brief description of drawings]

FIG. 1A is a cross-sectional view showing a measurement target of a displacement measuring device according to the present invention. (B) It is a figure which shows the displacement data of a measuring object. (C) It is a figure which shows the brightness | luminance data of a measuring object.

FIG. 2 is a measurement sensor connected to the displacement measuring device of the present invention.

FIG. 3 is a schematic block configuration diagram of a displacement measuring device of the present invention.

FIG. 4 is a flow chart when the displacement measuring device of the present invention measures solder.

FIG. 5 is a diagram showing measurement data output to a data conversion unit.

FIG. 6 is a diagram showing solder data conversion.

FIG. 7 is a flowchart when the displacement measuring device of the present invention measures a reference mark.

FIG. 8 is a diagram showing data conversion of reference marks.

FIG. 9 is a schematic block configuration diagram showing a conventional displacement measuring device.

[Explanation of symbols]

2 ... Projector 6 ... Light receiving part 12 ... A / D converter 15 ... Arithmetic processing unit 16 ... Alarm output section 19 ... Data converter 24 ... Dark alarm output section 25 ... Bright alarm output section W ... Measurement target Z ... Displacement data Z '... Indefinite displacement data G ... Luminance data G '... Indefinite brightness data

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F065 AA01 AA06 AA19 AA20 BB02                       CC01 CC26 DD08 FF09 FF23                       FF41 FF67 GG04 HH03 HH12                       JJ03 JJ08 JJ16 LL15 LL28                       LL62 MM15 NN13 NN17 QQ03                       QQ06 QQ23 QQ25 QQ27 QQ31                       SS09 UU05                 2F112 AA02 BA14 CA12 CA13 FA03                       FA07 FA08 FA45

Claims (3)

[Claims] 1. Light received by a light projecting section (2) toward a measurement target (W) and reflected at an irradiation position of the measurement target is received by a light receiving section (6) and is output by the light receiving section. A displacement measuring device for measuring displacement of the irradiation position by obtaining displacement data (Z) of the irradiation position from a measurement signal, the A / D converter (12) for A / D converting the measurement signal.
An alarm output unit (16) that outputs alarm data based on a signal output from the A / D conversion unit; and, when the alarm data is output, based on displacement data in the vicinity of the irradiation position, A displacement measuring device comprising: a data conversion unit (19) for invalidating the displacement data corresponding to the output alarm data. 2. The alarm output section, when the signal output from the A / D conversion section is less than a predetermined value, the displacement data near the irradiation position is indefinite value displacement data (Z ′). The displacement measuring device according to claim 1, wherein a dark alarm is output to warn that the data conversion unit ignores or flattens the indefinite value displacement data when the dark alarm is output. 3. The light receiving section (6) receives the light emitted from the light projecting section (2) toward the measurement target (W) and reflected at the irradiation position of the measurement target, and is output by the light receiving section. A displacement measuring device for measuring displacement of the irradiation position by obtaining displacement data (Z) and luminance data (G) of the irradiation position from a measurement signal, the A / D conversion for A / D converting the measurement signal. Division (12)
And a bright alarm that warns that the displacement data and the luminance data are indefinite value displacement data (Z ′) and indefinite value luminance data (G ′), respectively, when the A / D converter is in a saturated state. An output unit (25), and a data conversion unit (19) for ignoring the indefinite value displacement data and emphasizing the indefinite value luminance data when the bright alarm is output. Displacement measuring device.