JPH0477710A - Synchronous scanning microscope - Google Patents

Abstract

PURPOSE:To enable accumulation for a long time without deviating a picture by correcting the address of a memory based on the signal of an output side detecting a scanned result while writing a picture data in the memory according to the signal of an input side for driving a scanning mechanism. CONSTITUTION:A light deflector 3 has structure to deflect a laser beam made incident on two galvanometer mirrors/in two directions orthogonally with each other by turning the mirrors, to scan a sample 7 with the laser beam. A sensor 4 is arranged near the turning shaft of this galvanometer mirror so as to detect the turning position of the galvanometer mirror. The output value of this sensor 4 is transmitted to a control part 12 as a position signal, and correction is executed based on the drift amount of a fine optical spot or the like. In this case, since the address of the data to be stored in a frame buffer is corrected while referring to the output value of the sensor 4, there is no deviation in picture elements.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a synchronous scanning microscope that scans a sample with a minute light spot and takes an image in synchronization with this scanning.

[Prior art]

As a synchronous scanning microscope, a microscope is known that scans a sample with a micro spot for illumination using a laser beam, magnifies the image of the sample, and captures the image in synchronization with the scanning (Japanese Patent Application Laid-Open No. 6-0-1).
81718). In this synchronous scanning microscope, image data detected from the imaging device is written into the frame memory in synchronization with the scanning (input) signal of the optical deflector.

[Invention or problem to be solved]

However, in conventional synchronous scanning microscopes, when a drift occurs in the optical deflector, the actual optical spot position and the data address position stored in the frame memory do not match, and the image data is stored in a shifted state. Therefore, there was a drawback that pixel shift occurred when integrating images, and the resolution of the laser microscope decreased.

Therefore, the present invention aims to solve the above-mentioned drawbacks.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a light source, an illumination optical system, a scanning mechanism, a sensor, an imaging device, a storage means, and a correction means.

Here, the light source emits a laser beam, the illumination optical system uses the laser beam to form a minute light spot on the sample, and the scanning mechanism deflects the laser beam to form a minute light spot on the sample. scan.

Further, the sensor detects the deflection angle of the laser beam deflected by the scanning mechanism or the scanning position of the minute light spot, and the imaging device receives light from the sample and detects image data.

Further, the storage means writes image data from the imaging device in synchronization with the scanning signal of the scanning mechanism, and the correction means corrects the address position of the data stored in the storage means based on the output value from the sensor.

[Effect]

Since the present invention is configured as described above, image data is stored in the storage means (for example, frame memory) in synchronization with the scanning signal of the scanning mechanism. However, if something like a drift occurs in the scanning mechanism and the address of the data stored in the storage means and the minute light spot/nod are out of alignment, the address position of the data is corrected based on the scanning position information output from the sensor. .

Therefore, the position of the beam spot focused on the sample is always the same, regardless of the drift characteristics of the scanning mechanism.
Matches the data address of the storage means.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A synchronous scanning microscope according to an embodiment of the present invention will be described below with reference to the accompanying drawings. In addition, in the description, the same reference numerals are used for the same elements, and redundant description will be omitted.

FIG. 1 shows a synchronous scanning microscope according to a first embodiment of the present invention. This synchronous scanning microscope includes a laser oscillator (light source) 1, an illumination optical system 2, an optical deflector (scanning mechanism) 3, a sensor 4, an image dissector tube (imaging device) 5, and a synchronous scanning circuit 6. There is.

The illumination optical system 2 includes a condenser lens 2a, a spatial filter 2b, a lens 2c, a relay lens (second lens) 2d, and an objective lens (first lens) 2e, and uses laser light to generate a minute light spot. is formed on sample 7. The light output from the laser oscillator and condensed by the condensing lens 2a enters the spatial filter 2b and the lens 2c, and enters the optical deflector 3 as parallel light with a shaped beam.

The optical deflector 3 has a structure that rotates two galvanometer mirrors to deflect the laser beam incident on the mirrors in two mutually orthogonal directions, and scans the laser beam irradiated onto the sample 7. Ru. A sensor 4 is disposed near the rotation axis of the galvanometer mirror to detect the rotation position of the galvanometer mirror. This sensor 4
The output value is sent to the control unit 12 as a position signal, and is corrected based on the amount of drift of the minute light spot.

A relay lens 2d and an objective lens 2e are arranged on the output side of the optical deflector 3, so that the laser beam can be focused to the diffraction limit and irradiated onto the sample 7. Since the relay lens 2d is arranged so that the deflected laser beam is focused and incident on the pupil near the rear focal point of the objective lens 2e, the deflection position of the optical deflector 3 and the pupil of the objective lens 2e are in a conjugate relationship. It has become. An x-y-z stage 9 on which a sample 7 is placed is arranged on the optical axis output side of the objective lens 2e,
By moving the stage in three different directions, sample 7
The lighting conditions can be adjusted. The light from the sample 7 is collected by an objective lens 10 and an imaging lens 11 that constitute a magnifying optical system arranged above the Dissector
tube) 5.

A control section 12 equipped with a frame buffer (storage means) is connected to the image dissector tube 5.

FIG. 2 is a block diagram showing the circuit configuration of the synchronous scanning microscope according to the above embodiment. The control unit 12 described above includes a CPU.
12aSD/A converter 12b1A/D converter]
, 2c, 12d, a frame buffer 12e1 and a lookup table 12f. The look amplifier table 1.2 f is a symmetrical table created in advance that corresponds to the address of the data stored in the frame buffer 1.2 e and the position of the lotus beam spot indicated by the first scanning signal. has been done. Therefore, when scanning data indicating the first scanning signal for driving the optical deflector 3 as a digital value is sent to this lookup table 12f, based on this scanning data, the frame buffer 12e
, and the image data detected from the image dissector tube 5 is written to this address in synchronization with the first scanning signal. At this time, the address of the data stored in the frame buffer 12e is corrected by referring to the position signal from the optical deflector drive section 8, so even if a drift occurs in the optical deflector 3, the memory address and The beam spots always match, and no pixel misalignment occurs. As a correction method, for example, the first scanning signal and the position signal are compared, and the address position stored in the frame buffer is corrected based on the difference. In this case, in order to improve the S/N ratio of the obtained image data, the data after correction is also integrated and averaged.

FIG. 3 schematically shows the image memory address area and beam spot in the frame buffer 12e. Figure (a) shows an ideal state in which the beam spot 17 is located within the memory address area 16, and Figure (b) shows an ideal state in which the beam spot 17 is located within the memory address area 16.
indicates a drift state when a drift occurs in the optical deflector 3. According to the conventional synchronous scanning microscope, image data is written to the data address stored in the frame buffer 12e in synchronization with the scanning signal that drives the optical deflector 3. Therefore, when a drift occurs in the optical deflector 3, The memory address area and the spot position did not match, resulting in pixel misalignment (see FIG. 3(b)).

However, in the synchronous scanning microscope according to this embodiment, the sensor 4
frame buffer 12e while referring to the output value from
Since the address of the data stored in is corrected, the pixel shift as described above is eliminated.

FIG. 4 shows an example of the structure of the image dissector tube 5 (Japanese Patent Application Laid-Open No. 60-181718, Golds
tain (1989), “A confocal vi.
deo-rateaser-beam scatter
ring reflected-1jght cro
scope with no moving
parts-, Journal of Microsc
opy, Vol.]57. Pt, 1. January
1990. pp. 29-38). The image dissector tube 5 includes a photocathode 5a and a photoelectronic image concentrator 5b.
, a photoelectronic dog deflector 5c, an aperture plate 5d, a secondary electron multiplier 5e, an anode 5f, and a photocathode 5.
A minute light spot deflected by the optical deflector 3 is irradiated onto a. This minute light spot is converted into a photoelectron stream, and the deflection is controlled by the photoelectron dog deflector 5C based on the second scanning signal. Therefore, control is performed to closely match the scanning of the optical deflector 3, and the photoelectron flow is focused on a single point where the pinhole of the aperture plate 5d is located. The photoelectrons transmitted through the aperture plate 5d are multiplied by the secondary electron multiplier 5e, and then taken out from the anode 5f and output as image data.

FIG. 5 shows the relationship between aperture and photoelectron density. FIG. 3(a) shows the density of photoelectrons incident on the aperture of the synchronous scanning microscope according to the present example, and FIG. 2(b) shows the density of photoelectrons incident on the aperture of the conventional synchronous scanning microscope.

In the synchronous scanning microscope of this embodiment, the deflection of the image dissector tube 5 is controlled based on the output signal of the sensor 4, so its scanning coincides with the scanning of the optical deflector 3, and the aperture plate 5d is irradiated. The vicinity of the peak value of the photoelectron density of the photoelectron flow is taken into the aperture.

As shown in FIG. 2, the image data detected by the image dissector tube 5 is taken into the frame buffer 12e via the preamplifier 13 and the A/D converter 12c in synchronization with the first scanning signal.

Next, a synchronous scanning microscope according to a second embodiment of the present invention will be described. FIG. 6 shows a synchronous scanning microscope according to the second embodiment. The difference from the first embodiment is that a semiconductor device detection element (PSD) is installed outside the optical deflector as a sensor.
18 is used. Semiconductor device detection element 18
is a non-divided element that applies a silicon photodiode, and it receives continuous electrical signals (X coordinate signal, Y coordinate signal).
The position of the light spot can be detected.

A part of the incident light of the laser beam deflected by the optical deflector 3 is reflected by the beam splitter] 9, and then the laser beam is reflected by the imaging lens 20.
is guided to the semiconductor device detection element 18 via.

Therefore, the position of the minute spot of the laser beam formed by the optical deflector 3 is detected by the semiconductor device detection element 18. This detection signal is equivalent to the above-mentioned position signal and is sent to the control section 12, and based on this detection signal,
The position of the data address stored in the frame buffer of the control unit 12 is corrected.

According to the second embodiment, there is no need to incorporate a sensor inside the optical deflector 3, and the memory address of the frame buffer 12e can be corrected based on the amount of drift of the minute light spot caused by the optical deflector 3.

Note that the present invention is not limited to the above embodiments,
For example, an electro-optic crystal or an acousto-optic crystal can be used as the optical deflector.

Further, in the above embodiment, a finite correction optical system is used as the objective lens, but an infinite correction optical system can also be constructed.

Furthermore, although the above embodiments are explained using a transmission microscope, by using a beam splitter or a dichroic mirror, a reflection microscope can be constructed with one objective lens.

〔Effect of the invention〕

In the present invention, the image data is not written into the memory using the input side signal for driving the scanning mechanism, but the address of the memory is corrected based on the output side signal that detects the scanning result, so there is no image shift. Can be integrated over a long period of time.

In addition, it can perform microscopy with higher resolution and higher contrast than ordinary optical microscopes, such as transmission, reflection, fluorescence, and differential interference.

Furthermore, since the objective lens is placed in the optical path formed between the illumination scanning mechanism and the sample, the laser beam can be focused to the diffraction limit.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a synchronous scanning microscope according to the first embodiment of the present invention, FIG. 2 is a block diagram showing an example of a circuit configuration applicable to the synchronous scanning microscope according to the first embodiment, and FIG. 3 is an image. A schematic diagram showing the positional relationship between the memory address and the beam spot, FIG. 4 is a schematic diagram showing a configuration example of an image dissector tube that can be used in the above embodiment, and FIG. 5 is an image dissector tube in the above embodiment and a conventional example. FIG. 6 is a schematic diagram showing a synchronous scanning microscope according to a second embodiment of the present invention. 1... Laser oscillator, 2... Illumination optical system, 3... Optical deflector (illumination scanning mechanism), 4... Sensor, 5... Image dissector tube (imaging device), 6... For synchronous scanning Circuit (synchronization means), 7... Sample, 8... Optical deflector drive section, 9... xyz stage, 10. Objective lens,
11... Imaging lens, 13... Preamplifier, 14.
...Amplifier, 15...Power amplifier, 16...Image memory address, 17...Beam spot, semiconductor device detection element (PSD) 9...Beam splitter, 0...Imaging lens.

Claims (1)

[Claims] 1. A light source that emits a laser beam; an illumination optical system that uses the laser beam to form a minute light spot on a sample; a scanning mechanism that scans a sample; a sensor that detects a deflection angle of a laser beam deflected by the scanning mechanism or a scanning position of the minute light spot; and a sensor that receives light from the sample and detects image data of the sample. an imaging device that writes image data from the imaging device; a storage device that writes image data from the imaging device in synchronization with a scanning signal of the scanning mechanism; and a storage device that corrects an address position of data stored in the storage device based on an output value from the sensor. A synchronous scanning microscope comprising a correction means. 2. The illumination optical system includes a first lens disposed between the sample and the scanning mechanism that focuses the deflected laser light to the diffraction limit and irradiates the sample; Claim 1 further comprising: a second lens disposed between the lens and the scanning mechanism to make the rear focal position of the first lens and the deflection position of the scanning mechanism conjugate.
Synchronous scanning microscope as described.