JP2003194514A - Displacement measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To minimize the size of an unused area in a storage section storing displacement data and to shorten transferring time. <P>SOLUTION: A displacement calculating means 12 calculates the displacement data of an object W to be measured from measured signals. A main scanning counter 13 repeatedly counts the main scanning time (t) of laser light of one main scanning amount. An auxiliary scanning counter 15 counts the number of main scanning times of the laser light. An address generating means 19 generates an address composed of a low-order bit showing the count value (a) of the main scanning counter 13, and a high-order bit representing the count value (b) of the auxiliary scanning counter 15. A main scanning speed changing means 18 can change the main scanning speed S of the laser light, and the maximum count value P of the main scanning counter 13 is set based on the main scanning speed S and the main scanning time 5. A bit width changing means 19 changes the bit width allocation between the high- and low-order bits in accordance with the change of the main scanning speed of the laser light. <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 designed to perform a main scanning with a laser beam in a main scanning direction with a predetermined main scanning width, and also to scan in a sub scanning direction orthogonal to the main scanning direction. The present invention relates to a displacement measuring device that measures a displacement at a measurement target position by triangulation from a measurement signal obtained by receiving a reflected laser beam.

[0002]

2. Description of the Related Art A measuring sensor of a displacement measuring device includes a scanning light-projecting unit for main-scanning a laser beam in a main-scanning direction with a predetermined main-scanning width, and a laser beam reflected by the target. It has a light receiving element that operates. When measuring the displacement of the measurement object, the measurement sensor scans the laser light in the main scanning direction with respect to the measurement object, and the transport unit (not shown) on which the measurement object is placed is orthogonal to the main scanning direction in the sub-scanning direction. Move to.
Then, the displacement of the measurement target is measured in a non-contact manner by the measurement signal obtained from the light receiving element.

FIG. 13 is a schematic block diagram showing a signal processing system of a conventional displacement measuring device 50. When the laser light is imaged on the light receiving element 51, a pair of current signals based on the imaged position is output to the displacement calculation means 52. The displacement calculation means 52 executes displacement calculation processing by this current signal,
Displacement data including displacement and brightness of the measurement target is calculated.

In parallel with the displacement calculation means 52, a main scanning counter 53, a sub-scanning counter 54 and an address generating section 55.
And are provided. In the laser displacement meter using triangulation, the displacement of the height of the measurement target causes a shift in the measurement point. In order to correct this shift, assuming that the address in the sub-scanning direction is corrected, the address generated by the address generation unit 55 has a count value in the main-scanning direction of the lower bit and a count in the sub-scanning direction. The numerical value is the high-order bit,
It is divided into two parts. Therefore, the maximum count value in the main scanning direction and the sub scanning direction is a power of 2.

The main scanning counter 53 repeatedly counts the main scanning time corresponding to the scanning width of the laser light. Sub-scanning counter 5
4 indicates that when the count value of the main scanning counter 53 reaches the main scanning time of one main scanning width of the laser light (for example, the count value 3000), the measurement target is relatively moved in the sub-scanning direction by the conveyance of the conveyance unit (not shown) As it moves, the sub-scanning counter 54 counts and the upper bits carry up. The count value of the main scanning counter 53 and the count value of the sub-scanning counter 54 are output to the address generator 55.

The displacement data are stored in the memory 56, which is a small capacity memory, in the order of addresses generated by the address generator 55. FIG. 14A is a diagram showing a storage state of displacement data in the storage unit 56. In FIG. 14A, the maximum count value for one main scanning is a power of 2 (12 bits; 409).
6), the number of displacement data for one main scan is 30
00 data. Here, this number of data is a value determined by the performance of the optical system of the measurement sensor, the main scanning width of the laser light, the response of the light receiving element, and the resolution in the image processing in the subsequent stage, and therefore the lower bit in the main scanning direction Does not match the power of 2 which is the maximum count value of. As a result, an unused area in which the displacement data is not stored is generated in the storage unit 56.

When the stored data reaches a predetermined amount, it is collectively transferred to the large capacity memory 57.

The displacement measuring device 50 has a function of adjusting the main scanning speed of the measuring sensor according to the resolution in the image processing in the subsequent stage. For example, if the main scanning speed is doubled, the main scanning time of one main scanning width of the laser light becomes 1/2, and the count value for one main scanning in the main scanning counter at that time becomes 1500. Therefore, the resolution is also halved.

However, when the main scanning speed is doubled and the count value of the main scanning counter 53 becomes 1500, the difference from the maximum value of the lower bits increases. Therefore, the storage unit 5
As shown in FIG. 14B, the storage state of the displacement data in 6 is such that the unused area where the displacement data is not stored is increased, and the storage area of the storage unit cannot be effectively used. Further, as a result, when data transfer is executed from the storage unit 56, the transfer amount of the unused area data in the unused area increases and the transfer amount of the displacement data decreases, and the data transfer of the displacement data as a whole is performed. Time will increase. That is, although the number of pieces of displacement data for one main scan is halved, the number of times of data transfer does not change, so that the data transfer efficiency for displacement data deteriorates. Further, as a result, if the transfer time increases, the image processing in the subsequent stage will also be delayed.

On the other hand, if the main scanning speed is halved, for example, the main scanning time of one main scanning width of the laser beam is doubled,
The count value for one main scan in the main scan counter at that time is 6000. As a result, the maximum count value of the lower bits exceeds the power of 2 (4096), the address of the excess part is not generated, and the displacement data corresponding to the address cannot be stored. That is, even if the measurement can be performed by the measurement sensor, there is no storage place for the displacement data, so the displacement data is wasted.

From these things, if the bit width of the lower bits of the address is fixed, it cannot cope with the adjustment of the main scanning speed of the measuring sensor, and when the measured displacement of the measuring object is image-processed, The resolution cannot be set stepwise.

[0012]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and its purpose is to address an address in accordance with a change in the main scanning speed of laser light. It is intended to minimize the unused area in the storage unit in which the displacement data is stored by adjusting the bit width of. Further, by doing so, the efficiency of the storage area of the displacement data in the storage unit can be improved. Furthermore, the transfer time can be shortened by efficiently transferring the data stored in the storage unit collectively.

[0013]

A means for solving the above-mentioned problems will be described with reference to the accompanying drawings. The displacement measuring apparatus according to claim 1 of the present invention main-scans a laser beam with a predetermined main-scanning width d in the main-scanning direction X with respect to the measurement target W, and also sub-scanning direction Y orthogonal to the main-scanning direction. Scanning, from the measurement signal obtained by receiving the laser light reflected by the measurement target, a displacement measuring device for measuring the displacement at the measurement target position by triangulation, of the measurement signal from the measurement signal A displacement calculator 12 for calculating displacement data, a main scanning counter 13 for counting a main scanning time t of the laser beam during the one main scanning, and a sub-scanning counter 15 for counting the number of main scannings of the laser beam. , A main scanning speed control means 18 for controlling a main scanning speed S of the laser light and setting a maximum count value of the main scanning counter on the basis of the main scanning speed; Address generating means 16 for generating address data consisting of bits and upper bits representing the count value b of the sub-scanning counter, and the bit width of the upper bits and the lower bits in accordance with the change in the main scanning speed of the laser light. And a bit width adjusting means 19 for adjusting distribution.

A displacement measuring device according to a second aspect is the displacement measuring device according to the first aspect, wherein the bit width adjusting means starts from a last address where displacement data obtained by one main scan is stored. Bits of the high-order bit and the low-order bit so that an address interval G to the first address where displacement data obtained in the next main scan is stored is less than the data length of the displacement data for one main scan. It is characterized by adjusting the width distribution.

Further, in the displacement measuring device according to claim 3, in the displacement measuring device according to claim 1, the bit width adjusting means calculates a bit width distribution between the upper bits and the lower bits by a mathematical expression UP−P < It is characterized in that it is adjusted so as to satisfy U / K. However, U is the maximum count value of lower bits after bit width adjustment. P is the maximum count value of the main scanning counter set according to the changed main scanning speed. K is the radix of the lower bits.

A displacement measuring device according to a fourth aspect is the displacement measuring device according to any one of the first to third aspects, in which the displacement data is stored in accordance with the address data, and the storage means And a transfer unit 17 for transferring the displacement data stored in the storage unit together with the data in the unused area in the storage unit.

Laser light is scanned toward the object W to be measured in the main scanning direction X by a predetermined main scanning width d. Each time main scanning is performed by one main scanning, scanning is performed in the sub-scanning direction Y orthogonal to the main scanning direction X. The scanned laser light is reflected from the measuring object W and received by the light receiving element 9. A measurement signal based on the light receiving position on the light receiving element 9 is output. The displacement calculator 12 calculates the displacement data of the measurement target W based on the output measurement signal.

On the other hand, the main scanning counter 13 repeatedly counts the main scanning time t of the laser light for one main scanning. Further, the sub-scanning counter 15 also counts the number of main scans of the laser beam that has been main-scanned for the main scan. The count value a of the main scanning counter 13 is output to the lower bits of the address, and the count value b of the sub-scanning counter 15 is output to the upper bits of the address to be the address to the storage means 20.

Each generated address is output to the storage means 20. Each displacement data is stored for each address and serves as position information for the image processing unit in the subsequent stage.

Next, the main scanning speed S is changed. The maximum count value P of the main scanning counter 13 is set based on the main scanning speed S after the shift and the main scanning time t for one main scanning. Then, the bit width distribution between the upper bits and the lower bits is adjusted. As a result, compared with the case where the bit width is fixed, it is possible to cope with the change in the main scanning speed S of the measurement sensor 1, and when the measured displacement of the measurement target W is subjected to image processing, the resolution is set stepwise. It becomes possible to do.

When the measuring object W is conveyed after the bit width adjustment, displacement data is calculated and an address is generated. The displacement data is stored in the storage means 20 according to the address.

The storage state of the storage means 20 is such that the address interval G from the last address of the displacement data obtained in one main scan to the first address of the displacement data obtained in the next main scan is one main scan. It is less than the data length of minute displacement data.

In other words, the maximum count value U of the lower bits
And the maximum count value P of the main scan counter 13 set according to the changed main scan speed S is less than 1 / K of the maximum count value U of the lower bits after the adjustment of the bit width. . This difference becomes the address interval G, which is the number of unused area data for one main scan.

The stored displacement data is transferred together with the unused area data. Since the number of unused area data is reduced by adjusting the bit width, the transfer amount of unused area data can be reduced and the transfer amount of displacement data can be increased. Further, this makes it possible to shorten the transfer time of the entire displacement data.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a measurement state by a displacement measuring device. As shown in FIGS. 1A and 1B, the measurement sensor 1 is scanned toward the measurement target W (for example, an electronic component) with laser light in the main scanning direction X, and the measurement target W is scanned in the main scanning direction. The sheet is conveyed in the sub-scanning direction Y orthogonal to X. In the displacement measuring device 10, the distance image shown in FIG. 1C is generated by the laser light reflected from the measuring object W.

FIG. 2 is a schematic diagram showing the measurement 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 polygon mirror built therein, and a light projecting lens 5. As shown in FIG. 3, the scanning unit is composed of a scanner 4a for scanning the laser light, a drive unit 4b for rotating the scanner 4a at a predetermined speed, and a main scanning start means 4c. The scanner 4a is, for example, a polygon mirror or a galvanometer mirror. The laser light emitted from the laser light source 3 is measured by the rotation of the polygon mirror 4a.
On the other hand, the main scanning is performed by a predetermined main scanning width d.

The main scanning starting means 4c is, for example, a photodetector provided in the light projecting section 2 and detects that the laser beam scanned by the rotation of the polygon mirror is blocked by a shield. The scanning start signal is output to the main scanning counter 28.

The light receiving section 6 includes a light receiving lens 7 and an image forming lens 8.
The laser light reflected from the measuring object W is collimated by the light receiving lens 7 and is imaged as a single light spot on the light receiving element 9 by the imaging lens 8. The light spot moves on the light receiving element 9 following the scanning of the laser light of the light projecting unit 2.

The object W to be measured is placed on a transport unit (not shown). The transport unit is provided with a drive mechanism and moves at a constant speed in the sub-scanning direction Y orthogonal to the main scanning direction X.

FIG. 3 is a schematic block diagram showing a signal processing system of the displacement measuring device. The signal processing board has a CPU
11 and storage means 20 are mounted, the input side can be connected to the measurement sensor 1, and the output side is connected to the personal computer 30 via a general-purpose bus.

The CPU 11 is composed of, for example, a highly integrated logic circuit capable of writing a program, and the displacement calculating means 1
2, the main scanning counter 13, the CLK 14, the sub scanning counter 15, the address generating means 16, the transfer means 17, the main scanning speed control means 18, and the bit width adjusting means 19.

When the laser light is imaged on the light receiving element 9, a pair of amplified measurement signals based on the imaged position is output to the displacement calculating means 12. The displacement calculation means 12 executes displacement calculation processing based on this measurement signal, and calculates displacement data including the displacement and brightness of the measurement target W.

The main scanning counter 13 repeatedly counts the main scanning time for one main scanning of the laser light. A main scan start signal and a clock pulse are input to the main scan counter 13. Then, the number of clock pulses is counted after the main scanning start signal is input. When the number of counted clock pulses reaches the maximum count value of the main scanning counter 13 described later, a carry-up signal is output to the sub-scanning counter 15 and the count value a of the main scanning counter 13 is reset. The maximum count value of the main scanning counter 13 is updated to the maximum count value that is increased / decreased by the shift in the main scanning speed control means 18 described later. Sub-scanning counter 15
Counts each time the carry-up signal from the main scanning counter 13 is input.

The address generation means 16 generates the address data of the storage means 20 in order to store the displacement data in the storage means 20. Address data is the main scan counter 1
Lower bit representing the count value a of 3 and the sub-scanning counter 15
And a high-order bit representing the count value b of. The high-order bit and the low-order bit have the same radix K. For example, K
= 2 is a binary number, K = 8 is an octal number, K = 10
If it is, it is expressed in decimal, and if K = 16, it is expressed in hexadecimal. The address length of the address data is the sum of the bit width u of the lower bits and the bit width h of the upper bits. Therefore, the maximum count value U of the lower bits is u of K.
It becomes a square. Also, the maximum count value H of the upper bits is K to the h-th power.

The count value a of the main scanning counter 13 is sequentially written in the lower bits of the address data, and the count value b of the sub-scanning counter 15 is written in the upper bits of the address data.
Are sequentially written. The generated address data is sequentially output to the storage means 20.

The main scanning speed control means 18 can change the main scanning speed of the laser beam. That is, when the main scanning time for one main scanning (one line) is t and the main scanning width is d, the main scanning speed S (S = ns) is ns = d / t. n is a speed increase / decrease value of the main scanning speed s. The main scanning time t corresponds to the clock pulse number p. Therefore, the main scanning speed ns is ns = nd / p = d / (p / n). (P
/ N) is the maximum count value P of the main scanning counter 13. n
When the main scanning speed is normal when = 1, the maximum count value P of the main scanning counter 13 increases when 0 <n <1, and 1
When <n, the maximum count value P of the main scanning counter 13 decreases.

The main scanning speed ns set by the main scanning speed control means 18 is output to the drive section 4b of the scanning means 4.
The driving unit 4b rotates the scanner 4a according to the input main scanning speed ns. Further, the main scanning counter 1 corresponding to the main scanning speed ns set by the main scanning speed control means 18.
The maximum count value p / n of 3 is output to the bit width adjusting means 19 and the main scanning counter 13.

The bit width adjusting means 19 adjusts the distribution of the bit width h of the high-order bits and the bit width u of the low-order bits of the address based on the maximum count value p / n of the input main scanning counter 13. After the adjustment, the adjusted maximum count value U of the lower-order bits and the maximum count value P of the main scanning counter 13 set according to the changed main scanning speed (P = p /
n), the difference G (G = UP) is less than 1 / K (G <U / K) of the maximum count value U of the lower bits after adjustment. The difference G is an address interval from the last address where the displacement data obtained in one main scan is stored to the first address where the displacement data obtained in the next main scan is stored. It is the number of unused area data generated by one main scan.

The storage means 20 is composed of a small capacity memory and stores displacement data in accordance with each address output from the address generation means 16. The transfer means 17 detects the remaining capacity in the storage means 20 or the capacity of the stored data, and stores the displacement data stored in the storage means 20 in the large capacity memory 31 of the personal computer 30 side. Transfer with unused area data. A measurement image is obtained by repeating this. That is, the storage unit 20 and the transfer unit 17 form a ring buffer.

Personal computer 30 to which the signal processing board is connected
An image processing means 32 and a large capacity memory 31 are provided in the. The image processing means 32 is an image processing program installed in the personal computer 30. The image processing program can be executed by the CPU of the personal computer 30. The large-capacity memory 31 is, for example, the HDD of the personal computer 30.
Etc., and has a storage area in which data transferred by a plurality of data transfers can be sufficiently stored.
The display unit 33 is composed of, for example, a liquid crystal display or the like. Then, when the displacement data Z and the brightness data G temporarily stored in the storage means 20 of the signal processing board are transferred to the large-capacity memory 31 via the general-purpose bus at any time, the image processing means 32 causes, for example, a measurement target. Posture recognition and shape measurement of W are performed. The measurement image can be displayed on the monitor by the display unit 33.

FIG. 6A is a diagram showing the storage state of the displacement data in the storage means 20. In each main scan, P addresses, which are the same as the maximum count value of the main scan counter 13, are continuously generated. When the main scanning counter 13 reaches the maximum count value P, the sub-scanning counter 15 is counted and the address transits to U. Therefore, from the maximum count value P of the main scan counter 13 to the maximum count value U of lower bits (K to the u-th power). The displacement data is not written to the addresses up to () and becomes unused area data. Therefore, the addresses where the displacement data are stored are 1 to P, U to P + U, 2U to P + 2U,
3U to P + 3U, ..., bU to P + bU (b is the count value of the sub-scanning counter 15).

Next, the operation of this embodiment will be described. First, the measurement sensor 1 performs main scanning in the main scanning direction X on the measurement target W, and moves the measurement target W in the sub scanning direction Y to perform sub scanning with the laser light.

The laser beam reflected from the measuring object W is imaged on the light receiving element 9, and a measurement signal corresponding to the image forming position is output. The output measurement signal is input to the displacement calculator 12 and outputs displacement data.

On the other hand, when the main scanning start signal is output from the scanning means 4 (ST1), the main scanning counter 13 starts counting the clock pulse number a (ST2). The count value a of the main scanning counter 13 is the maximum count value P of the main scanning counter 13.
When it is below (ST2-NO), the main scanning counter 13
1 is incremented by 1 (ST3) and sequentially output to the address generation means 16 to generate an address (ST).
4). The generated address is output to the storage means 20,
The displacement data is stored in the generated address (ST
5). When the count value a of the main scanning counter 13 exceeds the maximum count value P of the main scanning counter 13 (ST2-YES),
The count value of the main scanning counter 13 is reset to 0, the count value b of the sub-scanning counter 15 is increased by 1 (ST6), and the count value b of the sub-scanning counter 15 is the first digit bit of the upper bits, that is, The entire address is output at the u + 1th digit.

When the remaining capacity in the storage means 20 is equal to or larger than the maximum count value U of the lower bits (ST7-NO), ST2
Move to. Then, in ST3, the sub-scanning counter 1
5 is counted first, then the address generated by the count value a of the main scanning counter 13 in ST4 is not continuous with the address generated immediately before, and the address between them is not generated. Therefore, the storage means 20
There will be an unused area inside.

When the remaining capacity in the storage means 20 is less than the maximum count value U of the lower bits (ST7-YE)
S), the displacement data is stored up to the address (P + bU), and the number of stored displacement data is bP. Then, the transfer means 17 transfers the displacement data to the large capacity memory together with the unused area data (ST8). Then, the sub-scanning counter 15 is reset to 0 (ST
9).

To continue the measurement (ST10-N
O), transition to ST2. To end the measurement (ST
10-YES), and ends.

Next, the case where the main scanning speed is changed will be described. The main scanning speed S before the change is relatively set to S = s (n = 1) with respect to the main scanning speed after the change. The main scanning speed is changed by an operation unit (not shown) (ST11). When the main scanning speed before and after the change is the same (n = 1) (S
(T12-YES), the distribution of the upper bit width and the lower bit width is unchanged (ST13).

When the main scanning speed after the change is acceleration (1 <n) or decelerated (0 <n <1) before the change (S
T12-NO), the maximum count value of the main scanning counter 13 is adjusted from the initial value p pulse to p / n pulse. The adjusted p / n pulse is output to the main scanning counter 13, and the maximum count value P of the main scanning counter 13 is updated from p to p / n (ST14).

Here, in the bit width adjusting means 19, the maximum count value U (K power of K) of the lower bits before the bit width adjustment is performed.
And the updated maximum count value P (p of the main scanning counter 13
/ N) is calculated (ST15). Difference G (G
= UP) is less than 1 / K of the maximum count value U of lower bits (G <U / K) (ST16-YES), it is not necessary to change the bit width (ST13). On the other hand, when it is 1/2 or more of the maximum count value U of the lower bits (G ≧ U / K) (ST16-NO), the bit width distribution between the upper bit width and the lower bit width is changed (ST17). In the bit width adjusting means 19, the maximum count value U (K power of K) of the lower bits after the bit width is changed and the updated main scanning counter 13
The difference G between the maximum count value P (p / n) of
18). When the difference G (G = UP) is 1 / K or more of the maximum count value U of the lower bits (G ≧ U / K) (ST1
9-NO), the bit width distribution between the upper bit width and the lower bit width is changed again (ST17). On the other hand, the difference G (G =
UP-P) is less than 1 / K of the maximum count value U of the lower bits (G <U / K) (ST19-YES), it is not necessary to change the bit width any more, and the bit width adjustment is completed. To do.

The displacement data is again stored and transferred (ST1 to ST1) according to the lower bit width thus adjusted.
0) is performed. Here, the bit width adjusting means 19 shown in FIG.
The storage state of the storage means 20 of the displacement measuring device not provided with and the bit width adjusting means 19 shown in FIG. 7 are provided, and the main scanning speed is adjusted so that the difference G becomes G <U / K. The storage state of the storage means 20 in the case of In both cases, the main scanning speed is set to be n times higher than that before the adjustment. 6A and 7A show a normal data storage state.

In the case of FIG. 6B, the main scanning speed is accelerated (1
If <n), the maximum count value P of the main scanning counter 13 decreases, but since the lower bit width u does not change, unused area data that is the address interval G ′ of the storage means 20 with the displacement data string. The number (unused area) increases as n increases.

On the other hand, in the case of FIG. 7B, the bit width is adjusted so that the difference G at each address interval is G <U / K. The difference G is stored in the storage unit 20 per main scanning.
Is the number of data in the unused area. That is, in one main scan, the displacement data number P after the bit width adjustment is larger than 1 / K of the maximum count value U of the lower bits after the bit width adjustment and less than the maximum count value U of the lower bits after the bit width adjustment. (U / K <P <U). Therefore, the displacement data number P after the bit width adjustment does not exceed the unused region data number. As a result, the number of unused area data can be reduced, and more displacement data can be stored in the storage unit 20.

When data is transferred from the storage state shown in FIG. 6B, the data is stored in the transfer destination large capacity memory as shown in FIG. 6C. On the other hand, when data is transferred from the storage state shown in FIG. 7B, in the large capacity memory of the transfer destination, FIG.
Is stored as. Comparing the transferred data,
The number of displacement data in the main scanning direction X is both P and the same, but the count value of the sub-scanning counter is Kb in FIG. 7C.
On the other hand, FIG. 6 (c) becomes b. Therefore, if the bit width is adjusted, K times of data transfer can be performed per transfer. Further, the address interval G in FIG.
Since it is significantly smaller than the address interval G ′ in (c), the unused area data amount KbG in FIG. 7C is significantly smaller than the unused area data amount bG ′ in FIG. Data transfer can be minimized.

Here, the data transfer time when data is transferred from the storage means 20 having the same capacity will be compared with reference to FIG. FIG. 8A is a time chart showing a transfer time when data is transferred from the storage state of FIG.
7B is a time chart showing a transfer time when data is transferred from the storage state of FIG. 7. In the case of FIG. 6, one data measurement time is tm. On the other hand, in the case of FIG. 7, the data measurement time of-is K · tm. K
The reason for being doubled is that the displacement data is stored K times that in FIG. Therefore, in the case of FIG.
The data transfer count is T times. On the other hand, in the case of FIG. 7, when the main scanning speed is adjusted and the difference G is G <U / K, it is sufficient to transfer the data T / K times. Since the storage means 20 have the same capacity, the data transfer time tf is the same.

In FIG. 8A, the data transfer time is T
(Tm + tf). On the other hand, in FIG. 8B, the data transfer time is T / K · (K · tm + tf). When this difference is obtained, it becomes T · tf (1-1 / K). Therefore, in the present embodiment, as compared with the conventional displacement measuring device in which the bit width adjusting means 19 is not provided, T · tf.
(1-1 / K) time is shortened.

Further, as shown in FIG. 9B, the main scanning speed is decelerated (0 <n <1) from the normal state shown in FIG. 9A.
Then, the maximum count value P of the main scanning counter 13 increases, but since the lower bit width is fixed, the minimum main scanning speed is also fixed. That is,
The maximum count value P of the main scanning counter 13 can be increased only up to the maximum count value U of the lower bits. Therefore, there is a limit in trying to obtain a higher resolution.

On the other hand, in the case of FIG. 10B, as in the case of FIG. 7B, the bit width is adjusted from the normal state shown in FIG. The maximum count value P of the main scanning counter 13 can be increased beyond the maximum count value U. Therefore, a higher resolution can be obtained and the measurement accuracy can be improved.

[0059]

EXAMPLE As an example, FIG. 11 is used to compare before and after main scanning speed acceleration. The radix K is K = 2. Further, as shown in FIG. 11A, before the main scanning speed acceleration, the shift value n = 1 and the maximum count value P = p / n of the main scanning counter 13.
= 3000, the bit width u of the lower bits u = 12, and the maximum count value U of the lower bits U = 2 ¹² = 4096.

As shown in FIG. 11B, when the main scanning speed is doubled (n = 2), the maximum count value P of the main scanning counter 13 becomes P = 1500. When the bit width of the lower bit is not changed, the difference G (G = U
-P) becomes 4096-1500 = 2596. 25
Since 96 is larger than U / 2 = 2048 which is 1/2 of the maximum count value U of the lower bits before adjustment, the lower bits are set to 1
Decrease the bit and increase the upper bit by 1 bit. The bit width u of the lower bits is u = 11, and the maximum count value U =
2 ¹¹ = 2048. Difference G after bit width change (G =
UP-P) becomes 2048-1500 = 548. 54
8 is smaller than U / 2 = 1024 which is 1/2 of the maximum count value U of the adjusted lower bits. As a result, the unused area can be reduced.

Further, in FIG. 12A, in the configuration in which the bit width adjusting means 19 is not provided, it is possible to expand the image in the entire measurement area by the number of data transfers T = 6 times. on the other hand,
In FIG. 12B, the number of times of data transfer may be T / K = 3, and the time difference from FIG. 12A is 3tf, and the tact time of data transfer is improved by this time.

[0062]

In the displacement measuring apparatus of the present invention, the bit width of the address data can be adjusted according to the change in the main scanning speed of the laser beam, so that the resolution is higher than that when the bit width is fixed. Displacement data can be obtained.

Further, by adjusting the bit width of the address data in accordance with the change in the main scanning speed of the laser light, it is possible to minimize the unused area in the storage means in which the displacement data is stored. . Therefore, the limited storage area of the storage means can be effectively utilized, and the efficiency of data storage can be improved.

Furthermore, the transfer time can be shortened by collectively transferring the data stored in the storage means efficiently by adjusting the bit width.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a displacement measurement state by a displacement measurement device.

FIG. 2 is a schematic perspective view showing a measurement sensor.

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

FIG. 4 is a flowchart showing storage and transfer of displacement data of the displacement measuring device of the present invention.

FIG. 5 is a bit width adjustment flowchart of the displacement measuring device of the present invention.

FIG. 6A is a diagram showing a storage state of displacement data in a storage unit before acceleration of a main scanning speed. FIG. 7B is a diagram showing a storage state of displacement data in the storage unit after the main scanning speed acceleration in the case where the bit width adjusting unit is not provided. FIG. 7C is a diagram showing data transferred to a large capacity memory.

FIG. 7A is a diagram showing a storage state of displacement data in a storage unit before acceleration of a main scanning speed. FIG. 7B is a diagram showing a storage state of displacement data in the storage unit after the main scanning speed acceleration when the bit width adjusting unit is provided. FIG. 7C is a diagram showing data transferred to a large capacity memory.

FIG. 8A is a timing chart showing data transfer when a bit width adjusting unit is not provided. (B) is a timing chart showing data transfer when a bit width adjusting means is provided.

FIG. 9A is a diagram showing a storage state of displacement data in a storage unit before deceleration of a main scanning speed. FIG. 6B is a diagram showing a storage state of the displacement data in the storage unit after deceleration of the main scanning speed when the bit width adjusting unit is not provided.

FIG. 10A is a diagram showing a storage state of displacement data in a storage unit before deceleration of a main scanning speed. FIG. 7B is a diagram showing a storage state of displacement data in the storage unit after deceleration of the main scanning speed when the bit width adjusting unit is provided.

FIG. 11A is a diagram showing a storage state of displacement data before acceleration in a main scanning speed in a storage unit in the embodiment (a). FIG. 7B is a diagram showing a storage state of the displacement data in the storage unit after the main scanning speed acceleration when the bit width adjusting unit is provided in the example (b). FIG. 6C is a diagram showing data transferred to a large capacity memory in the embodiment.

FIG. 12A is a timing chart showing data transfer when the bit width adjusting means is not provided in the embodiment (a). (B) is a timing chart showing data transfer in the case where the bit width adjusting means is provided in the embodiment.

FIG. 13 is a schematic block diagram showing a conventional displacement measuring device.

FIG. 14A is a diagram showing a conventional storage state of displacement data in a storage unit before acceleration in a main scanning speed. FIG. 6B is a diagram showing a storage state of displacement data in a storage unit after the conventional main scanning speed acceleration.

[Explanation of symbols]

12 ... Displacement calculation means 13 ... Main scanning counter 15 ... Sub-scanning counter 16 ... Address generating means 17 ... Transferring means 18 ... Main scanning speed control means 19: Bit width adjusting means 20 ... Storage means a ... Count value of main scanning counter b ... Count value of sub-scanning counter d ... Main scanning width t ... Main scanning time G: Address interval P ... Maximum count value of main scanning counter S ... Main scanning speed of laser light W ... Measurement target X ... Main scanning direction Y ... Sub scanning direction

Claims (4)

[Claims] 1. A main scanning direction (X) of a laser beam with a predetermined main scanning width (d) with respect to an object to be measured (W) and a sub-scanning direction (Y) orthogonal to the main scanning direction. Scanning, from the measurement signal obtained by receiving the laser light reflected by the measurement target, a displacement measuring device for measuring the displacement at the measurement target position by triangulation, of the measurement signal from the measurement signal Displacement computing means (12) for computing displacement data, a main scanning counter (13) for counting a main scanning time (t) during the one main scanning of the laser beam, and a main scanning number of the laser beam. A sub-scanning counter (15) for controlling the main scanning speed (S) of the laser beam, and a main scanning speed control means (18) for setting a maximum count value of the main scanning counter based on the main scanning speed. , The main scanning counter Address generating means (16) for generating address data consisting of a lower bit representing a count value (a) and an upper bit representing a count value (b) of the sub-scanning counter; And a bit width adjusting means (19) for adjusting a bit width distribution between the upper bit and the lower bit. 2. The bit width adjusting means starts from the last address where displacement data obtained in one main scan is stored.
The upper bit and the lower bit are set such that the address interval (G) to the first address where the displacement data obtained in the next main scan is stored is less than the data length of the displacement data for one main scan. 2. The displacement measuring device according to claim 1, wherein the bit width allocation of the displacement measuring device is adjusted. 3. The bit width adjusting means calculates a bit width distribution between the upper bits and the lower bits by a mathematical expression UP−P <
The displacement measuring device according to claim 1, wherein the displacement measuring device is adjusted so as to satisfy U / K. However, U is the maximum count value of lower bits after bit width adjustment. P is the maximum count value of the main scanning counter set according to the changed main scanning speed. K is the radix of the lower bits. 4. A storage means (20) for storing the displacement data according to the address data, and a transfer means (17) for transferring the displacement data stored in the storage means. The displacement measuring device according to any one of claims 1 to 3.