JP3319567B2 - Motor control device for confocal microscope - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a motor control device for a confocal microscope, and more particularly to an improvement in scan speed control.

[0002]

2. Description of the Related Art Conventionally, a real-time confocal microscope for observing an image of a sample surface by performing optical scanning by rotating a Nipkow disk provided with a plurality of minute openings (usually pinholes) with a motor is well known. . In this type of microscope, an image of the sample surface is captured using a CCD (Charg Coupled Device).
ce) Some cameras take images and observe them. in this case,
The speed of one scan of the entire screen is the video rate (33m
It must be an integral multiple of s).

[0003]

If the speed of one scan deviates from an integral multiple of the video rate, CC
There is a problem in that the number of scans varies depending on the location in the screen while one screen is captured by the D camera, and as a result, bright and dark stripes appear on the observed image.

The relationship between the scanning speed and the observation screen is shown in FIGS.
As shown in FIG. An example is shown in which scanning is performed with four light beams (circles in the figure indicate spots of light beams, and lines with arrows indicate moving directions). FIG. 3 shows that the speed of one scan is equal to an integral multiple of the video rate. In this case, no bright and dark stripes appear on the screen as shown in FIG. However, FIG.
In the case of overscan as described above, there is a portion that is scanned twice at the upper part of the sample surface, and the upper part of the screen becomes an image brighter than the lower part as shown in FIG. FIG.
In the case of insufficient scanning as described above, an insufficient scanning portion occurs at the lower part of the sample surface, and the lower part of the screen becomes a dark image.

In FIG. 1, a scan using four rays is taken as an example. However, in reality, the number of rays is larger, and a plurality of dark stripes are displayed on the screen due to the overlap of the rays as shown in FIG. appear.

The motor synchronizes the rotation speed with the imaging time of the CCD camera based on the NTSC signal output from the CCD camera.
If the C signal input becomes abnormal, there is a problem that the rotation of the motor stops or the motor stops rotating at high speed.

In view of the foregoing, it is an object of the present invention to obtain an image having no scanning unevenness and no stripes by controlling the number of rotations of a motor for rotating a Nipkow disc based on an NTSC signal of a CCD camera. It is an object of the present invention to realize a motor control device for a confocal microscope that can be used. Another object of the present invention is to realize a motor control device of a confocal microscope that prevents a large abnormality in rotation of a motor even when an NTSC signal input becomes abnormal.

[0008]

According to the present invention, there is provided a motor control system for use in a real-time confocal microscope for rotating a Nipkow disk with a motor to perform optical scanning and observing an image of a sample surface. A vertical synchronizing signal extracting circuit for extracting a vertical synchronizing signal from an NTSC signal output from a CCD camera for observing an image of the sample surface; a frequency multiplying circuit for multiplying and outputting the vertical synchronizing signal; A motor drive circuit for driving the motor at a speed corresponding to the control signal output from the frequency multiplier is provided.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of a motor control device for a confocal microscope according to the present invention. In the figure, 1
Is a CCD camera for capturing an image of the sample surface optically scanned by a confocal microscope, 2 is an NTS sent from the CCD camera 1
A vertical synchronizing signal extracting circuit for extracting a vertical synchronizing signal from the C signal, 3 is a frequency multiplying circuit for multiplying the output frequency of the vertical synchronizing signal extracting circuit, and 4 is an output signal of the frequency multiplying circuit 3 (here, called a control signal). It is a motor drive circuit that drives the motor 5 based on the above.

The operation in such a configuration will be described below. The vertical synchronization signal extraction circuit 2 extracts a vertical synchronization signal from the NTSC signal output from the CCD camera 1. The frequency multiplying circuit 3 multiplies this vertical synchronizing signal and outputs it. The motor driving circuit 4 drives the motor 5 so as to rotate at a speed corresponding to the control signal from the frequency multiplying circuit 3, that is, at a speed that is an integral multiple of the video rate.

As a result, the speed of scanning the sample surface is synchronized with the time for capturing one screen with the CCD camera. In this case, the motor is not fixedly rotated at a constant speed, but is controlled by a signal from the CCD camera 1. Therefore, even if the NTSC signal fluctuates, the motor rotates following the NTSC signal and the sample surface is scanned. No stripes appear in the captured image.

In order to prevent the motor from stopping or abnormally high speed rotation when the NTSC signal becomes abnormal due to noise or attenuation, the following configuration is adopted. As shown in FIG. 2, a PLL (Phase Locked) incorporating a voltage controlled oscillator (VCO) is used as the frequency multiplying circuit 3.
(Loop) A circuit composed of a circuit 31 (commercially available as an integrated circuit) and a counter 32 is used. Here, the counter 32 is used as frequency dividing means.

The oscillation frequency of the VCO in the PLL circuit 31 can be adjusted by a capacitor C external to the PLL circuit and resistors R ₁ and R ₂ . Therefore, the oscillation capacitor and the resistor are set so that the oscillation frequency is close to the maximum output frequency of the PLL 31, and the frequency band of the motor control signal output from the frequency multiplier 3 is limited. As a result, unreasonable acceleration and high-speed rotation of the motor 5 are automatically suppressed. It should be noted that even if noise is superimposed on the NTSC signal and this control works and synchronization with the CCD camera 1 is lost, there is substantially no problem in visual observation.

It is to be noted that the foregoing description of the present invention has been presented by way of illustration and example only and is of particular preferred embodiments. Thus, it will be apparent to one skilled in the art that the present invention may be modified or modified in many ways without departing from its essentials.

[0015]

As described above, according to the present invention, the speed at which the screen of the sample is scanned is synchronized with the time when one screen is picked up by the CCD camera. Can be easily obtained. Also,
CCD instead of rotating the motor at a certain speed
Since the control is performed based on the signal from the camera, even if the NTSC signal fluctuates, the fluctuation follows the fluctuation and no bright and dark stripes appear on the image. Furthermore, by limiting the rotation speed of the motor,
Even if the NTSC signal greatly fluctuates, excessive acceleration and high-speed rotation of the motor can be suppressed, and there is an effect that the life of the motor is not shortened.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a motor control device of a confocal microscope according to the present invention.

FIG. 2 is a configuration diagram showing another embodiment of the present invention.

FIG. 3 is an explanatory diagram when a scan speed and a video rate match.

FIG. 4 is an explanatory diagram in the case of overscan.

FIG. 5 is an explanatory diagram in the case of an insufficient scan.

FIG. 6 is a conceptual explanatory diagram showing the occurrence of light and dark stripes on a screen.

[Explanation of symbols]

1 CCD camera 2 vertical synchronizing signal extraction circuit 3 frequency multiplier circuit 4 motor drive circuit 5 motor 31 PLL circuit 32 the counter C capacitors R _1, R ₂ resistor

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-66753 (JP, A) JP-A-9-80315 (JP, A) JP-A-5-341191 (JP, A) JP-A-4-341 161915 (JP, A) Japanese Utility Model Application Hei 4-59817 (JP, U) US Patent 4,802,748 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 21/00

Claims (2)

(57) [Claims] 1. A motor control device used in a real-time confocal microscope for rotating a Nipkow disk with a motor to perform optical scanning and observing an image of a sample surface, wherein the motor control device outputs an image from a CCD camera that observes the image of the sample surface A vertical synchronizing signal extracting circuit for extracting a vertical synchronizing signal from the NTSC signal to be obtained, a frequency multiplying circuit for multiplying and outputting the vertical synchronizing signal, and a motor corresponding to a control signal output from the frequency multiplying circuit. A motor control device for a confocal microscope comprising a motor drive circuit for driving a motor. 2. The frequency multiplying circuit uses a PLL circuit having a built-in voltage-controlled oscillator so that the oscillation frequency of the voltage-controlled oscillator approaches the maximum output frequency of the PLL circuit to limit the rotation speed range of the motor. The motor control device for a confocal microscope according to claim 1, wherein the motor control device is configured.