JP5176616B2 - Confocal scanner unit - Google Patents

Description

  The present invention relates to a confocal scanner unit suitable for use in a confocal microscope, and relates to a confocal scanner unit that uses a low-output brushless sensorless motor to improve rotational speed accuracy and reduce vibration.

  A confocal microscope to which the present invention is applied observes a sample by scanning a condensing point on the sample with a laser beam (hereinafter referred to as measurement light), forming an image of return fluorescence from the sample, and obtaining an image. Therefore, it is used for observation of physiological reactions and morphology of living cells in the fields of living organisms and biotechnology, or for LSI surface observation in the semiconductor market.

First, the confocal microscope will be briefly described.
FIG. 5 is a functional block diagram showing a configuration example of a conventional confocal microscope. The confocal scanner unit 1 is connected to a port of the microscope unit 2. The measurement light L is condensed into an individual excitation light beam L1 by a microlens formed on the microlens array disk 11 of the confocal scanner unit 1, passes through a dichroic mirror 12, and is then a pinhole array disk (hereinafter, “Nipou disk”) 13. Are focused on the sample 4 on the stage 3 by the objective lens 21 of the microscope unit 2.

The sample 4 generates fluorescence by irradiation with the excitation light beam L1. Return fluorescence L from sample 4
2 passes through the objective lens 21 again and is condensed on each pinhole of the Niipou disc 13. The return fluorescence that has passed through each pinhole is reflected by the dichroic mirror 12 and is imaged on the light receiving surface of the CCD element 51 provided in the camera 5 via the relay lens 14.

  The microlens array disk 11 and the tip disk 13 are coaxially coupled and are rotationally driven at a predetermined speed by a motor 16 whose rotation is controlled by a motor driver 15. The condensing point on the sample 4 is scanned by the movement of the pinhole on the Nipo disk 13 by this rotation.

Since the surface where the pinholes of the Niipou disc 13 are arranged, the surface to be observed of the sample 4 and the light receiving surface of the CCD element 51 are arranged in an optically conjugate relationship with each other, the optical element of the sample 4 is placed in the CCD element 51. A cross-sectional image, that is, a confocal image is formed. The details of the Niipou disc type confocal microscope are disclosed in Patent Document 1.

In a confocal microscope having such a functional configuration, in order to obtain a stable confocal image with less noise, the rotation of the nippo disk is controlled with high accuracy, and the rotation scanning period of the nipou disk and the imaging period of the camera are synchronized. It is necessary to let

In the apparatus shown in FIG. 5, the rotation of the Nipkow disc 13 is detected by a rotation sensor 17 such as a photosensor.
And a trigger signal corresponding to the rotation of the Niipou disc 13 is generated by the scanning trigger generation circuit 6 and supplied to the motor driver 15 and the imaging trigger supply unit 7.

Motor driver 15 receives the trigger signal, so as to rotate the Nipkow disc 13 at a predetermined rotational speed, for driving the motor 16.

The imaging trigger supply unit 7 generates an imaging trigger signal in consideration of the vertical transfer time of the CCD element 51 from the trigger signal and passes it to the imaging control unit 8, and the imaging control unit 8 acquires a confocal image based on the imaging trigger signal. The imaging cycle of the camera 5 to be controlled is controlled.

In this way, when the rotation speed of the Nipkow disk and the imaging period of the camera 5 are controlled by the trigger signal obtained from the rotation sensor 17, the scanning of the sample by the excitation light beam L1 and the imaging of the confocal image by the camera 5 are accurately synchronized. It is possible to obtain a stable confocal image free from noise such as synchronization stripes.
For example, there are the following patent documents as prior art relating to the confocal scanner unit.

Japanese Patent Laid-Open No. 5-60980 JP 2006-145634 A

FIG. 6 is a block diagram showing an example of the Niipou disc 13 used for generating such a trigger signal. FIG. 6A shows a pulse signal synchronized with the position of the pinhole spiral row provided on the Niipou disc. A plurality of pinhole spiral rows are formed in the pinhole region 131 indicated by hatching, and a slit for generating a trigger signal corresponding to the rotational position of the Niipou disc 13 is provided in the outer encoder region 132. Yes. The example shown in the figure has 24 pinhole spiral rows, and 24 slits S <b> 1 to S <b> 24 are provided on the circumference of the encoder region 132.

Here, the slits S1 to S24 are formed at an equal pitch, and the pitch is one round (3
60 °) is divided by 24 to be 15 °.
Therefore, from the rotation sensor, a trigger signal of 24 pulses corresponding to the scanning position of the pinhole spiral row is obtained for each rotation of the Niipou disc 13, and can be used for synchronous control of the imaging operation.

FIG. 6B shows an example in which one pulse of trigger signal is generated per rotation. The encoder area 132 is provided with a slit S0 corresponding to an arbitrary reference position on the Niipou disc 13.
Therefore, a one-pulse trigger signal is obtained from the rotation sensor for each rotation of the Niipou disc 13 and can be used for rotation control of the Niipou disc 13.

It is possible to use a trigger signal of 24 pulses corresponding to the scanning position of the pinhole spiral row for the rotation control of the Niipou disk 13, but a trigger signal of 1 pulse per rotation is also required as an absolute reference for the rotation control. is there.

It is conceivable that a 2-track encoder area 132 is provided on the Nipkow disc 13 to simultaneously obtain a trigger signal of one pulse per rotation and 24 pulses per revolution.
In addition to the pinhole region 131, there is an alignment mark region and the like, and it is difficult to secure a wide range of encoder region 132.
In addition, since the 2-track encoder area 132 is read, the configuration of the rotation sensor is also complicated.

The present invention eliminates the disadvantages of the conventional apparatus as described above, obtains two types of trigger signals from the encoder area of one track, and reduces the induced voltage at a low speed, so that an accurate position can be obtained even in an area where the position is difficult to detect. It is an object to realize a confocal scanner unit that can perform sinusoidal driving, low current driving with smooth current driving, with a simple configuration.

In order to achieve such a subject, the present invention has the following configuration.
(1) A pinhole array disk in which a plurality of pinhole spiral rows are formed in a pinhole region and a microlens array disk having a microlens that collects an excitation light beam in the pinhole are coaxially coupled, and a sensorless brushless motor A confocal scanner unit configured to rotate,
Forming an equal pitch encoder pattern equal to the number of pinhole spiral rows on either the pinhole array disk or the microlens array disk;
While making the circumferential width of one encoder pattern different from other encoder patterns,
A scanning synchronization pulse generation circuit that reads a rising (or falling) edge in a pulse signal generated from a rotation sensor and generates a trigger signal corresponding to a scanning position of the pinhole spiral row;
A rotation synchronization pulse generating circuit that reads a pulse width in a pulse signal generated from the rotation sensor, detects a passage of an encoder pattern having a different width, and generates a trigger signal corresponding to the rotation of the Niipou disc;
A motor control unit that counts the trigger signal generated from the rotation synchronization pulse generation circuit and compares it with the rotation speed command value held in the rotation speed setting unit; and the counted trigger signal and the rotation speed setting unit A motor drive unit that controls the rotation of the Niipou disc to a predetermined rotational speed based on a deviation from the rotational speed command value,
The sine wave frequency of one phase of the three-phase AC voltage that drives the sensorless brushless motor is rotated in synchronization with an electric signal generated based on the encoder pattern and the rotation speed setting signal of the equal pitch. The confocal scanner unit that features.

(2) The confocal scanner unit according to (1), wherein when the rotation speed setting signal is a voltage input, the sensorless brushless motor is driven by converting the frequency into a frequency by a voltage frequency converter.

(3) The confocal scanner unit according to (1), wherein when the rotation speed setting signal is set by communication, the communication processing unit converts the frequency into a frequency and drives the sensorless brushless motor.

(4) The confocal scanner unit according to (1), wherein the encoder pattern is formed on an outer peripheral portion of the pinhole array disk or the microlens array disk.

(5) The confocal scanner unit according to (1), wherein the encoder pattern is formed on an inner periphery of the pinhole array disk or the microlens array disk.

In this way, an equal pitch encoder pattern equal to the number of pinhole spiral rows is formed on either the pinhole array disk or the micro lens array disk, and the circumferential width of one encoder pattern is set to the other encoder. When different from the pattern, if you read the rising (falling) edge in the pulse signal generated from the rotation sensor, you can get a trigger signal according to the scanning position of the pinhole spiral row,
If the pulse width in the pulse signal generated from the rotation sensor is read, a trigger signal corresponding to the rotation of the pinhole array disk can be obtained, and one-phase sine wave of the three-phase AC voltage for driving the sensorless brushless motor. Since the frequency is rotated in synchronism with the electric signal generated based on the encoder pattern having the equal pitch and the rotation speed setting signal, rotation accuracy at a low speed can be obtained.

Further, since the encoder area is only for one track, an extra area is not occupied, and the rotation sensor for reading the encoder pattern may have a simple configuration.

Hereinafter, the present invention will be described in detail with reference to the drawings.
First, the configuration of a pinhole array disk (hereinafter referred to as “Nipou disk”) used in the confocal scanner unit of the present invention will be described with reference to FIG. 2, the same components as those in FIG. 6 are denoted by the same reference numerals.

In the encoder area 132 of the Niipou disc 13, encoder patterns P1 to P12 having the same pitch as the number of pinhole spiral rows are formed. Here, a case where the number of pinhole spiral rows is 12 is illustrated, and the pitch of the encoder patterns P1 to P12 is 30 °.

Moreover, one encoder pattern P1 among the encoder patterns P1 to P12 is formed so that the circumferential width thereof is different from the other encoder patterns P2 to P12. In the example of FIG. 2, the pitch is equivalent to 13 ° in terms of pitch, and is narrower than the other encoder patterns P2 to P12. The circumferential widths of the other encoder patterns P2 to P12 are equivalent to 15 ° in terms of pitch.
The encoder pattern P1 is preferably a pattern at a position synchronized with the reference position of the Niipou disc 13.

In the encoder patterns P1 to P12 having such a positional relationship, if the tip position of each pattern is read, a trigger signal corresponding to the scanning position of the pinhole spiral row can be obtained, and if the width of each pattern is read, The passage of only one narrow encoder pattern P1 can be detected, and a trigger signal corresponding to the rotation of the Niipou disc 13 can be obtained.

FIG. 1 is a block diagram showing an embodiment of a confocal microscope using such a confocal scanner unit. In the figure, the same components as those in FIG. 5 are denoted by the same reference numerals. The Nipou disc 13 has encoder patterns P1 to P12 as shown in FIG. 2, and the rotation sensor 17 reads the encoder patterns P1 to P12 and generates binary pulse signals according to the presence or absence of the patterns.

The scanning synchronization pulse generation circuit 61 reads the rising (falling) edge in the pulse signal generated from the rotation sensor 17 and generates a trigger signal corresponding to the scanning position of the pinhole spiral row. This trigger signal is supplied to the imaging trigger supply unit 7 and used as an imaging cycle signal of the camera 5 that acquires a confocal image. This trigger signal is generated by 12 pulses for one rotation of the Niipou disc 13.

The rotation synchronization pulse generation circuit 62 reads the pulse width in the pulse signal generated from the rotation sensor 17, detects the passage of the narrow encoder pattern P1, and detects the Nipou disc 13
A trigger signal corresponding to the rotation of the signal is generated.

  The motor driver 15 includes a motor control unit 63a and a motor drive unit 64b. The motor control unit 63a counts the trigger signal generated from the rotation synchronization pulse generation circuit 62 and holds it in the rotation number setting unit 64. Compared with the specified rotation speed command value. This deviation is supplied to the motor drive unit 64b and controlled so that the rotation of the Niipou disc 13 becomes a predetermined rotation speed.

  By the way, in such a Niipou disc type confocal scanner unit, when a motor with a Hall element sensor is used, the size becomes large and it cannot be accommodated in the unit, so it is necessary to use a low-output sensorless motor.

  Conventional sensorless motor drive has adopted a 120-degree energization drive system in which the induced voltage is monitored and the position of the rotor is estimated and controlled. Since the magnitude of the induced voltage is proportional to the rotational speed, the induced voltage becomes small at a low speed, and an erroneous rotational position may be detected, and the rotational accuracy at a low speed cannot be obtained. In addition, the 120-degree energization drive method is a rectangular wave current drive, and therefore, it has an influence on vibration due to a steep fluctuation of current.

  In the present invention, as shown in FIG. 1, one of the three-phase induced voltages supplied from the motor driving unit 63b to the sensorless brush motor 16a is fed back to the motor control unit 63a and driven in phase. In FIG. 1, only a line for one phase is shown.

FIGS. 3A to 3D are explanatory diagrams showing a state in which the timing of each signal is matched to the rotation speed setting signal. Figure 3a is a setting signal from the rotational speed setting tough 64, Figure 3b the signal of the rotation sensor (photo sensor), one phase of the induced voltage of the Figure 3c is a three-phase induced voltages, Figure 3d shows the current waveform data The timing is measured by monitoring the encoder signal of 12 pulses per rotation from the rotation sensor (photo sensor) and the induced voltage of the sensorless brush motor 16a, and the sine wave data for T1, T2,. The phase is adjusted to drive.

  In this way, driving with T1, T2,..., T12 in phase with the sine wave data can reduce the internal processing burden and increase the rotational speed accuracy compared to vector control. it can. In this case, the rotation speed control is performed by controlling the amplitude of a sine wave with respect to an external rotation speed setting input and performing PLL control with a photosensor signal.

FIG. 4A and FIG. 4B are main part block configuration diagrams showing measures when a signal from the rotation speed setting unit is input in a state different from the frequency input. In FIG. 4, the same components as those shown in FIG.
FIG. 4a shows a countermeasure when a voltage is input to the rotation speed setting unit 64. Here, an example in which a voltage / frequency converter 65 is provided between the rotation setting unit and the motor control unit 63a is shown.
Further, providing the communication processing unit 66 and the frequency generator between the FIG. 4b shows the action to be taken if a setting by communicating the rotational speed setting unit 64 is made, the rotational speed setting unit 64 and the motor control unit 63a Example Is shown.

  As described above, the confocal scanner unit of the present invention can obtain two types of trigger signals from one track of the encoder area 132 (encoder patterns P1 to P12). Further, since the encoder area 132 is only for one track, an extra area is not occupied on the surface of the Niipou disc 13, and the rotation sensor 17 for reading the encoder patterns P1 to P12 may have a simple configuration.

In the above description, the encoder area 132 (encoder patterns P1 to P1
2) is provided on the outer periphery of the Nipkow disc 13, but the encoder region 132 (
The positions of the encoder patterns P <b> 1 to P <b> 12) are not limited to this, and may be the inner peripheral portion of the Niipou disc 13.

In the above description, the encoder area 132 (encoder patterns P1 to P1
Although the case where 2) is provided on the side of the Nipkow disk 13 is illustrated, the encoder area 132 (encoder patterns P1 to P12) may be provided on the side of the microlens array disk that is coaxially coupled to the Niipou disk 13.

Furthermore, in encoder pattern P1-P12, although the case where the width | variety of specific pattern P1 was formed narrower than other patterns P2-P12 was illustrated, the width | variety of specific pattern P1 is formed wider than other patterns P2-P12. Even in this case, the same operation can be performed.

  In the above description, an example in which twelve encoder patterns are provided in the encoder area 132 has been described. However, when the number of pinhole spiral rows increases or decreases, the number is increased or decreased accordingly.

It is a block diagram which shows an example of embodiment which applied the confocal scanner unit of this invention to the confocal microscope. It is a block diagram which shows an example of embodiment of the pinhole array disk used for the confocal scanner unit of this invention. It is explanatory drawing which shows the state which match | combined the timing of each signal with respect to a rotation speed setting signal. It is a principal part block block diagram (a) when rotation speed setting is voltage input. It is a principal part block block diagram (b) when rotation speed setting is made by communication. It is a functional block diagram which shows the structural example of the conventional confocal microscope. It is a block diagram which shows an example of a nipou disk.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Confocal scanner unit 2 Microscope unit 3 Stage 4 Sample 5 Camera 6 Scan trigger generation circuit 7 Imaging trigger supply part 8 Imaging control part 11 Micro lens array disk 12 Dichroic mirror 13 Pinhole array disk (Nipou disk)
DESCRIPTION OF SYMBOLS 14 Relay lens 15 Motor driver 16 Motor 21 Objective lens 51 CCD element 61 Scanning synchronous pulse generation circuit 62 Rotation synchronous pulse generation circuit 63a Motor control part 63b Motor drive part 64 Rotation speed setting part 65 Voltage / frequency conversion part 66 Communication processing part 67 Frequency generator 131 Pinhole area 132 Encoder area

Claims (5)

A configuration in which a pinhole array disk in which a plurality of pinhole spiral rows are formed in a pinhole region and a microlens array disk having a microlens for condensing excitation light flux in this pinhole are coaxially coupled and rotated by a sensorless brushless motor The confocal scanner unit of
Forming an equal pitch encoder pattern equal to the number of pinhole spiral rows on either the pinhole array disk or the microlens array disk;
While making the circumferential width of one encoder pattern different from other encoder patterns,
A scanning synchronization pulse generation circuit that reads a rising (or falling) edge in a pulse signal generated from a rotation sensor and generates a trigger signal corresponding to a scanning position of the pinhole spiral row;
A rotation synchronization pulse generating circuit that reads a pulse width in a pulse signal generated from the rotation sensor, detects a passage of an encoder pattern having a different width, and generates a trigger signal corresponding to the rotation of the Niipou disc;
A motor control unit that counts the trigger signal generated from the rotation synchronization pulse generation circuit and compares it with the rotation speed command value held in the rotation speed setting unit; and the counted trigger signal and the rotation speed setting unit A motor drive unit that controls the rotation of the Niipou disc to a predetermined rotational speed based on a deviation from the rotational speed command value,
The sine wave frequency of one phase of the three-phase AC voltage that drives the sensorless brushless motor is rotated in synchronization with an electric signal generated based on the encoder pattern and the rotation speed setting signal of the equal pitch. The confocal scanner unit that features.   2. The confocal scanner unit according to claim 1, wherein when the rotation speed setting signal is a voltage input, the sensorless brushless motor is driven by converting the frequency into a frequency by a voltage frequency conversion unit.   2. The confocal scanner unit according to claim 1, wherein, when the rotation speed setting signal is set by communication, the communication processing unit converts the frequency into a frequency to drive the sensorless brushless motor.     The confocal scanner unit according to claim 1, wherein the encoder pattern is formed on an outer periphery of the pinhole array disk or the microlens array disk.   The confocal scanner unit according to claim 1, wherein the encoder pattern is formed on an inner periphery of the pinhole array disk or the microlens array disk.

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