JPH1010449A - Scanner drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the adjustment of a circuit and other parts and to realize accurate scanner driving which is endurable to secular charge by comparing driving waveformn data for driving a scanner with the position data of the scanner and correcting the driving waveform data itself, based on the compared result. SOLUTION: The driving waveform data for driving a galvano mirror 25, which is stored in a memory 22, is compared with the position data in accordance with the deflection of the galvano mirror 25, which is fetched through an A/D 27, by a CPU 21. Based on the compared result, the driving waveform data in the memory 22 is corrected. Thus, the adjustment of a differential and integral calculus circuit and the gain adjustment of a servo are eliminated entirely as in the conventional device in which PID control is adopted. Since it is unnecessary to care about the pairing of the scanner and the driving system, the adjustment of each part for optimization is eliminated. Furthermore, the accurate scanner driving which is endurable to the secular change is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanner driving device for driving a scanner such as a galvanometer mirror used in a scanning confocal microscope.

[0002]

2. Description of the Related Art As is well known, a scanning confocal microscope irradiates an observation sample with laser light through an objective lens.
As a result, the light (transmitted light) or reflected light transmitted through the observation sample is condensed into a point again through the objective lens to form an image on a detector having a pinhole opening. I'm trying to get

FIG. 8 shows a schematic configuration of a conventional scanning confocal microscope. A point light emitted from a point light source 91 passes through a half mirror 92 and passes through an objective lens 93 whose aberration has been corrected. A point image is formed on the surface of the observation sample 94,
Also, the reflected light of the point illumination on the observation sample 94 passes through the objective lens 93 again, is reflected by the half mirror 92, and is condensed at the position of the pinhole 95, so that the light passing through the pinhole 95 is collected. The light is detected by a light detector 96. In this case, the spot-like illumination is two-dimensionally scanned by a scanner over the entire measurement area on the surface of the observation sample 94 by raster scanning or the like, and the detection signal by the photodetector 96 based on the reflected light from the observation sample 94 is displayed as an image. A two-dimensional image of the surface of the observation sample 94 is also obtained.

Conventionally, a galvanomirror is mainly used in such a scanner for two-dimensional scanning, and PID control using a calculus circuit is used for position control of such a galvanomirror. Then, an operation of applying analog feedback with a position signal from a galvanomirror is performed.

Japanese Patent Application Laid-Open No. 7-014184 discloses an example of such a galvanomirror driving device. A feedback loop is formed in a position control system of the galvanomirror, and the driving signal and the actual position of the galvanomirror are disclosed. The deviation from the signal is made to converge to a fixed amount by PID control.

[0006]

However, according to such a driving device, since the PID control is adopted, adjustment of the calculus circuit and adjustment of the servo gain are always required, which takes time and effort. Due to artificial fluctuations in the adjustment, the detection accuracy becomes unstable, and even if the adjustment is completed, the distortion of the system may not be completely removed. May have occurred.

Further, since the galvanomirror and the driving device after the adjustment are completely paired, if a part of the device is replaced, the adjustment of each part of the driving device must be performed each time for optimization. There was also a problem that it did not.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a scanner driving device which does not require adjustment, is resistant to aging, and can always realize a highly accurate scanner driving.

[0009]

According to the first aspect of the present invention,
A driving device for a scanner that moves and scans a focused light in a two-dimensional direction, a driving waveform storage unit that stores driving waveform data, and position data that captures position data of the scanner that is driven by the driving waveform data of the driving waveform storage unit. It is constituted by a fetching means and a control means for correcting the drive waveform data stored in the drive waveform storage means based on the position data fetched by the position data fetching means.

According to a second aspect of the present invention, in the first aspect, the control means compares the driving waveform data with the position data, and adds or subtracts the difference between the driving waveform data and the driving waveform data.

According to a third aspect of the present invention, in the first aspect, the control means includes a comparing means for comparing the driving waveform data with the position data, a clock generating means for generating a reference clock, and a comparison result of the comparing means. And a counter for counting a reference clock of the clock generator. The drive waveform data is corrected by the count value of the counter.

As a result, according to the present invention, the driving waveform data for driving the scanner, which is stored in the driving waveform storage means, is compared with the position data of the scanner, which is fetched by the position data fetching means. Since the drive waveform data itself in the drive waveform storage means is corrected based on the above, it is not necessary to adjust the circuit and servo gain as in the past, and be aware of the oneness of the scanner and the drive system. Since there is no need to make adjustments at various points for optimization, it is possible to realize a highly accurate scanner drive that is resistant to changes over time.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 shows a schematic configuration of a scanning confocal microscope to which the present invention is applied. In the figure,
Reference numeral 1 denotes a microscope main body, and the microscope main body 1 is configured as follows. Reference numeral 6 denotes a laser light source.
Generates laser light as spot light for scanning the surface of the sample 11 described later.

The laser beam from the laser light source 6 is transmitted to a scanner 2 via a mirror 7 which is a reflecting mirror.
It is guided to the dimensional scanning mechanism 5. The two-dimensional scanning mechanism 5 performs two-dimensional scanning of the laser light from the laser light source 6 obtained via the mirror 7, and controls the spot from the laser light source 6 under the control of the two-dimensional scanning drive control circuit 4. Light is scanned XY. In this case, the two-dimensional scanning mechanism 5 has, for example, a galvanometer mirror for scanning in the X-axis direction and a galvanometer mirror for scanning in the Y-axis direction, and swings these galvanometer mirrors in the X-axis direction and the Y-axis direction. The optical path of the spot light with respect to the objective lens 10 is shifted in the X and Y directions.

The spot light oscillated in the X and Y directions by the two-dimensional scanning mechanism 5 is applied to a sample 11 held on a stage 12 through an objective lens 10 held by a revolver 9.

In this case, the revolver 9 holds a plurality of objective lenses 10 having different magnifications.
By switching the objective lens 10 having a desired magnification among the plurality of objective lenses 10 in the observation optical path of the microscope, 2 is set via the objective lens 10 thus set.
The spot light from the dimensional scanning mechanism 5 is irradiated onto the sample 11 on the stage 12 while performing two-dimensional scanning.

On the other hand, the reflected light from the sample 11 is returned to the two-dimensional scanning mechanism 5 through the objective lens 10, and is further returned to the half mirror 8 from the two-dimensional scanning mechanism 5. The half mirror 8 is provided on an emission optical path of the laser light source 6 with respect to the two-dimensional scanning mechanism 5, and guides reflected light from the sample 11 obtained through the two-dimensional scanning mechanism 5 to a photodetector 15 described later. It consists of a translucent mirror.

The reflected light from the two-dimensional scanning mechanism 5 guided to the photodetector 15 from the half mirror 8 is detected by the photodetector 15 via the condenser lens 13 and the pinhole plate 14. ing.

Here, the pinhole plate 14 is provided with a pinhole having a required diameter, and is provided with the pinhole positioned at the focal position of the lens 13 on the front surface of the light receiving surface of the photodetector 15. I have. The photodetector 15 includes a photodetector that converts light obtained through the pinhole into an electric signal corresponding to the light amount. And this photodetector 1
5 converts the photoelectrically converted signal into a two-dimensional scanning drive control circuit 4
The image data is provided to the image processing unit 2 together with the timing signal from the controller 3 and is imaged, and is displayed on the monitor 3 to obtain surface information of the sample 11.

FIG. 2 shows a scanner driving apparatus according to the present invention applied to such a scanning confocal microscope.
1 shows a schematic configuration of a dimensional scanning drive control circuit 4. In this case, the CPU 21 is a microcomputer that controls the entire apparatus, and the CPU 21 has a data bus 201,
The memories 22, 28 and 30 are connected via an address bus 202.

The memory 22 stores drive waveform data, and is composed of, for example, a dual port ram. The memory 22 writes saw-tooth wave data for driving the galvano mirror 25 constituting the two-dimensional scanning mechanism 5 described above. In. The memory 30 also stores the drive waveform, and the CPU 30
It is used as a buffer memory for the operation at 21. The memory 28 stores the position data of the galvanometer mirror 25, and is configured as a dual port ram.

The data bus 20 is stored in the memory 22.
3, a D / A converter 23 is connected, and the D / A
A galvanomirror 25 is connected to the converter 23 via a variable gain amplifier 24. Also, galvanomirror 25
A / D converter 2 via a variable gain amplifier 26
7 and the A / D converter 27 is connected to the data bus 2
The memory 28 is connected via the control unit 04.

The D / A converter 23 converts the drive waveform data from the memory 22 into an analog voltage to be supplied to the galvanomirror 25. Variable gain amplifier 2
Numeral 4 is for varying the deflection angle of the galvanomirror 25, and varies the amplitude of the analog voltage from the D / A converter 23 under the control of the CPU 21 so as to vary the galvanomirror 2
5 is given.

The variable gain amplifier 26 includes a galvanomirror 2
This is to make the position signal (voltage) from 5 a constant amplitude regardless of the deflection angle. Then, the A / D converter 27
This is for converting the position signal (voltage) from the variable gain amplifier 26 into digital data and taking it in.

The memories 22 and 28 have an address bus 20
The timing circuit 29 is connected via the terminals 5 and 206. The timing circuit 29 generates a timing signal necessary for various operations and a timing signal for imaging surface information of the sample 11 under the control of the CPU 21.

Next, the operation of the first embodiment thus configured will be described with reference to the flowchart shown in FIG.
First, in step 301, as the ideal drive waveform data for driving the galvanometer mirror 25 by the CPU 21, for example, ideal saw-tooth waveform data as shown in FIG. expand.

The driving waveform data in this case is, for example, 12
It is a digital value in which the maximum value of the waveform is set to FFFh and the minimum value is set to 0h, and the number of data points constituting the sawtooth waveform is sequentially written to the memory 22 and the memory 30 while linearly increasing the digital value. . At this time, the inside of the memory 22 is divided into two banks, and the data at this time is developed in one bank.

Next, in step 302, the required deflection angle of the galvanometer mirror 25 is set in the variable gain amplifier 24 by the CPU 21. Then, in step 303, the CP
When a scan start command is output from U21, the timing circuit 29 is activated, and the timing circuit 29
While sequentially advancing the address of the memory 22 through the address bus 205, the waveform data is read from the memory 22;
The D / A converter 23 generates an ideal sawtooth wave (analog waveform) as shown in FIG.

Then, in the variable gain amplifier 24, the amplitude of the sawtooth wave is adjusted so as to have a predetermined swing angle, and this is supplied to the galvano mirror 25 as a drive waveform, whereby the actual galvanomirror 25 Scanning is performed.

When the galvanomirror 25 swings,
A position signal corresponding to the deflection angle is obtained, and the position signal is supplied to the variable gain amplifier 26. In this case, FIG.
It is desirable that a similar position signal waveform be obtained because the laser is driven by an ideal sawtooth wave as shown in FIG. 4A. However, if the position is partially distorted as shown in FIG. If the signal waveform is obtained, the surface information of the sample 11 to be imaged by this will be partially distorted.

In the variable gain amplifier 26, the amplitude of the position signal waveform given from the galvanomirror 25 is kept constant (A / D
(The same as the input range of the converter 27), and this is converted by the A / D converter 27 into digital position information.

The A / D converter 27 used here has the same number of bits as the D / A converter 23 used for generating the drive waveform. The digital conversion in the A / D converter 27 is performed at the timing of the timing circuit 29, and while the address of the memory 22 is updated by one while the data is converted by the D / A converter 23. Digital data is acquired as a position voltage corresponding to the drive voltage at that time.

The current position data is written to the memory 28 while the address of the memory 28 is sequentially advanced by the timing circuit 29, and the CPU 21 is notified when one waveform is written (step 304). The writing into the memory 28 is also performed in one of the two divided banks.

Upon receiving the notification from the timing circuit 29, the CPU 21 checks the data written in the memory 28 and detects the minimum value (or the maximum value) in step 305.

Here, since the number of waveform data points in the memory 30 is equal to the number of position data points in the memory 28, in step 306, the address of the minimum value (or maximum value) of the data written in the memory 28 and the Compare the data from the address of the minimum (or maximum) of the ideal waveform.

Then, in step 307, based on the result of comparison with the data (drive waveform data) Pn of the memory 30 and the data (position data) Qn of the memory 28, if these data are the same, the data is not updated. The data for correcting the distortion is written into the memory 22. in this case,
At step 308, the position data Qn <the driving waveform data P
n, and if YES, the difference is added to the drive waveform data Pn at step 309, and at step 310,
This value is written to the memory 22. On the other hand, if NO, the difference is subtracted from the drive waveform data Pn in step 311, and this value is written to the memory 22 in step 310.

If the first ideal waveform is written in the first half area of the memory 22, writing to the memory 22 is performed in the second half area. Such an operation is repeated while incrementing the address by +1 in step 313 until it is determined in step 312 that the number of data points has been completed.
Driving waveform data obtained by correcting the distortion shown in FIG. 3C for the position signal waveform having the distortion shown in FIG. 4B is obtained, and in step 310, the contents of the memory 22 and the memory 30 are updated.

In this case, the timing circuit 29 outputs new driving waveform data via the D / A converter 23 while switching the bank of the memory 22 for each cycle of the waveform.

As a result, new drive waveform data is given to the galvanomirror 25 in a state where distortion has been corrected, so that the position signal from the galvanomirror 25 becomes close to an ideal waveform. After the amplitude of the position signal is adjusted again by the variable gain amplifier 26, the A / D
The data is fetched by the converter 27 and stored in another bank of the memory 28 for each cycle similarly to the drive waveform data.

When the storage in the memory 28 is completed,
As described above, the timing circuit 29 notifies the CPU 21 of the data. The CPU 21 reads the data from the other bank, compares the data with the ideal drive waveform data (data of the memory 30), and updates the data of the memory 22. Go.

In this case, by dividing the memory 22 and the memory 28 into two banks, the driving waveform is read out from the memory 22 and generated by the D / A converter 23, and the corresponding position data is written into the memory 28. During this operation, the CPU 21 can calculate and update the data in the other bank, and can drive the galvanomirror 25 while always calibrating it.

By repeating the operations from step 304 to step 312 until a scan stop command is issued in step 314, the drive is performed so that the position data from the galvanomirror 25 always has an ideal waveform. The waveform data is modified. This means that once the galvanomirror 25 is scanned, its operation is controlled so as to have a linear characteristic.

Accordingly, with this configuration, the drive waveform data for driving the galvano mirror 25 stored in the memory 22 and the position corresponding to the shake of the galvanomirror 25 captured via the A / D converter 27 Data and C
Since the comparison is made by the PU 21 and the drive waveform data itself in the memory 22 is corrected based on the comparison result, there is no need to adjust the calculus circuit or the servo gain as in the case of the conventional PID control. In addition, since there is no need to be aware of the one-to-one correspondence between the scanner and the drive system, it is not necessary to make adjustments at various points for optimization, and it is possible to realize a highly accurate scanner drive that is resistant to aging. (Second Embodiment) FIG. 5 shows a schematic configuration of a second embodiment of the present invention.

In this case, the comparator 41 is connected to the CPU 41 via the address / data bus 401. The comparator 40 is connected to a memory 42 via a data bus 402 and an A / D converter 43 via a data bus 403. Further, one input terminal of the OR circuit 44 and the counter 45 are connected to the comparator 40.

Here, the memory 42 stores drive waveform data, and is composed of, for example, a dual port RAM.
Sawtooth wave data for driving the galvanomirror 25 is written. The A / D converter 43 is for taking in the position signal (voltage) of the galvanometer mirror 25 as digital data. The comparator 40 compares the ideal drive waveform data A from the memory 42 with the position data B from the A / D converter 43, and outputs the output (A ≠).
B) is made valid and applied to the OR circuit 44, and the output (A
> B or A <B) to the counter 45. The counter 45 is composed of an up / down counter, and counts up or down by an output (A> B or A <B) of the comparator 40,
The count value is supplied to the galvano mirror 25 from the D / A converter 48 as drive waveform data.

A clock circuit 46 is connected to the OR circuit 44, and a D / A converter 48 is connected to an output terminal via an A / D converter 43, a counter 45, and a NOT circuit 47.

The clock circuit 46 has a reference clock (CL
K) and a sampling clock (SCL) for imaging.
K), the reference clock (CLK) is supplied to the counter 45 while the output (A ≠ B) based on the comparison result from the comparator 40 is supplied to the OR circuit 44, and the sampling clock (SCLK) is generated. Is given to the counter 49. The counter 49 is SC
This is to generate the address of the memory 42 in response to the LK. Here, CLK having a frequency sufficiently higher than SCLK is used.

The D / A converter 48 converts the driving waveform data into an analog voltage to be applied to the galvanomirror 25, and passes through the variable gain amplifier 50 to the galvanomirror 25.
Give to. The variable gain amplifier 50 includes a galvanomirror 25
D / A converter 4
The amplitude of the analog voltage from 8 is variable.

The position signal (voltage) from the galvanometer mirror 25 is supplied to the A / D converter 43 via the variable gain amplifier 51. Variable gain amplifier 51
Is for making the position signal (voltage) from the galvanometer mirror 25 a constant amplitude irrespective of the deflection angle, and the A / D converter 43 is for taking in the position signal (voltage) as digital data.

The CPU 41 includes a galvanomirror 25
This is for expanding the ideal waveform data in the memory 42, expanding the data of the comparator 40, and controlling the start and stop of scanning.

Next, the operation of the second embodiment configured as described above will be described with reference to a timing chart shown in FIG. In this case, a memory is used as the comparator 40, and its data is as shown in FIG. In other words, the ideal waveform data and the position data are input to the upper (A) and lower (B) addresses of the memory, respectively, and data indicating the magnitude relationship between A and B is written to the address formed by the combination thereof. . For example, 2
Bits are used, 1 bit of which is 0 if A ≠ B, 1 if A = B, and 1 bit means 0 if A <B and 1 if A> B when A ＞ B. (For example, 00h or 01h if A ≠ B, 02h if A = B (03
h), the area indicated by the broken line may be provided as a dead zone so that A = B. Now, when the start of scanning is notified to the CPU 41, the counter 49 advances the address of the memory 42 by SCLK from the clock circuit 46, and ideal driving waveform data is supplied from the memory 42 to the comparator 40.

Here, assuming that the position data B from the A / D converter 43 is smaller than the drive waveform data A, the output (A ≠ B) of the comparator 40 becomes valid and CLK is supplied to the counter 45 through the OR circuit 44. Can be Since A> B here, the counter 45 counts up at the rising edge of CLK, and at the falling edge,
The incremented count value at this time is the D / A converter 4
The driving waveform is converted into a driving waveform via the amplifier 8, the amplitude is adjusted by the variable gain amplifier 50, and the adjusted waveform is supplied to the galvanomirror 25.

On the other hand, the position signal from the galvanometer mirror 25 is adjusted to have a constant amplitude (the same as the input range of the A / D converter 43) by the variable gain amplifier 51, and is converted into digital position data by the A / D converter 43. Is done.

In this state, the comparator 40 performs the comparison again and repeats the above-mentioned operation until the driving waveform data A and the position data B coincide with each other.
And the up-count is repeated. As a result, the drive waveform from the D / A converter 48 is adjusted and converges to the ideal position. That is, the counter 45 repeats the up-counting operation until the drive waveform data A and the position data B coincide with each other, so that the data becomes the target value n at the rise of the point a of CLK in FIG. At the fall, it is converted into drive waveform data, and at the rise of the point c, the comparator 40
If the position data n is taken in from the D converter 43 and the output (A ≠ B) becomes invalid during the time indicated by the hatched portion in the figure, the supply of CLK to the counter 45 is stopped by the OR circuit 44 and the target value n To be converged.

Next, when the SCLK is input to the counter 45, the target position changes to n + 1. Therefore, the comparator 40 again makes A ≠ B valid, and follows the above-described operation to change the galvanomirror 25 to the ideal waveform. Let them follow. On the way,
If the position data is larger than the drive data, the counter 45 inverts to down-counting, so that the counter 45 also attempts to converge to the target position.

As described above, in the second embodiment, the drive waveform data is corrected so that the position data from the galvanomirror 25 always becomes an ideal waveform by the judgment of the comparator 40. This means that once the galvanomirror 25 is scanned, its operation is controlled so as to have a linear characteristic.

Therefore, even in this case, it is not necessary to adjust the driving circuit, and the user does not need to be aware of the one-to-one correspondence between the mirror and the driving circuit.

[0058]

As described above, according to the present invention, the drive waveform data for driving the scanner, which is stored in the drive waveform storage means, is compared with the position data of the scanner, which is captured by the position data capture means. Since the drive waveform data itself in the drive waveform storage means is corrected based on this result, it is not necessary to adjust the circuit and the gain of the servo as in the prior art. Since there is no need to be conscious of it, it is not necessary to make adjustments in various places for optimization, and furthermore, it is resistant to aging and can realize high-precision scanner driving.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a scanning confocal microscope to which a first embodiment of the present invention is applied;

FIG. 2 is a diagram illustrating a schematic configuration of a two-dimensional scanning drive control circuit applied to the first embodiment;

FIG. 3 is a flowchart for explaining the operation of the first embodiment.

FIG. 4 is a view for explaining drive waveform data for driving the galvanometer mirror according to the first embodiment;

FIG. 5 is a diagram showing a schematic configuration of a second embodiment of the present invention.

FIG. 6 is a timing chart for explaining the operation of the second embodiment.

FIG. 7 is a view for explaining an example of comparator data according to the second embodiment;

FIG. 8 is a diagram showing a schematic configuration of a general scanning confocal microscope.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... microscope main body, 2 ... image processing unit, 3 ... monitor, 4 ... two-dimensional scanning drive control circuit, 5 ... two-dimensional scanning mechanism, 6 ... laser light source, 7 ... mirror, 8 ... half mirror, 9 ... revolver, 10 ... Objective lens, 11 ... Sample, 12 ... Stage, 13 ... Condenser lens, 14 ... Pinhole plate, 15 ... Photodetector, 21 ... CPU, 22 ... Memory, 23 ... D / A converter, 24 ... Variable gain amplifier , 25: Galvano mirror, 26: variable gain amplifier, 27: A / D converter, 28: memory, 29: timing circuit, 30: memory, 40: comparator, 41: CPU, 42: memory, 43: A / D converter , 44 ... OR circuit, 45 ... counter, 46 ... clock circuit, 47 ... NOT circuit, 48 ... D / A converter, 49 ... counter, 50 ... OK Gain amplifier.

Claims (3)

[Claims] 1. A driving device for a scanner that moves and scans focused light in a two-dimensional direction, comprising: driving waveform storage means for storing driving waveform data; and a position of the scanner driven by the driving waveform data of the driving waveform storage means. A scanner comprising: position data capturing means for capturing data; and control means for correcting drive waveform data stored in the drive waveform storage means based on the position data captured by the position data capturing means. Drive. 2. The scanner driving device according to claim 1, wherein the control means compares the drive waveform data with the position data, and adds / subtracts the difference to / from the drive waveform data. A control means for comparing the drive waveform data with the position data; a clock generation means for generating a reference clock; and a counter means for counting a reference clock of the clock generation means based on a comparison result of the comparison means. 2. The scanner driving device according to claim 1, wherein said driving waveform data is corrected by a count value of said counter means.