JP2845919B2 - Coherent optical scanning optical microscope - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a scanning optical microscope apparatus. In particular, the present invention relates to an improved apparatus of a coherent optical scanning optical microscope that performs two-dimensional scanning using an acousto-optic deflecting element (hereinafter referred to as AOD) and a galvanomirror deflecting element (hereinafter referred to as GMD).

[Problems to be Solved by Conventional Techniques and Inventions] Various advantages and disadvantages of a method of obtaining an image at a high speed by using AOD for X scanning have been reported. For example, Suzuki et al., "Laser Research," Vol. 15, No. 8, pp. 636-646 (Showa
August, 1962).

AOD using anisotropic Bragg diffraction is mainly used in terms of deflection angle and efficiency, but has many drawbacks due to its large dispersibility. In particular, there is a problem in observation with a fluorescent image. As a solution, for example, there is a proposal of Japanese Patent Publication No. 61-72214 by Lasertec. Each of these methods has an opening extending in the AOD deflection direction (X direction) and restricts information in the Y direction perpendicular to the opening. These are confocal with respect to the information in the Y direction of the sample, but take in a higher-order ring component in the X direction, which is not an ideal confocal system.

The present invention has been made to solve the above-mentioned problem. The present invention is an improvement on the conventional method of receiving light through a window corresponding to an opening extending in the X-ray scanning direction, and is an ideal confocal (confocal). It is an object of the present invention to provide a scanning optical microscope that enables the method.

[Means for Solving the Problems] The gist of the present invention is that light from a coherent light source is directed at a high speed in an X direction by an acousto-optic deflecting element and slowly at a Y direction by a galvanomirror deflecting element. In a coherent light scanning optical microscope apparatus having a light receiving element that scans a sample two-dimensionally through a lens and receives a return light or a transmitted light from the sample and generates an image signal, the light receiving element is arranged in the X direction. A photoelectric conversion element array that is arranged and has a pixel arrangement conjugate with a scanning point in the X direction on the sample, so as to obtain only information on the scanning point on the sample corresponding to each pixel of the photoelectric conversion element array, Driving means for driving the corresponding array, the driving means outputting a gate control signal synchronized with X-direction scanning, and the gate control corresponding to X-direction scanning A shift register that outputs a signal for each pixel, and a shift register arranged corresponding to each pixel of the photoelectric conversion element array, and the shift register reads only the pixel corresponding to the scanning point, and the other pixels are short-circuited. And a pair of analog switches for each pixel that is controlled to open and close.

Next, the scanning optical microscope according to the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Embodiment FIG. 1 is a schematic diagram showing an example of an optical arrangement of a scanning optical microscope of the present invention.

FIG. 2a is a schematic view of a photoelectric conversion element array used in the scanning optical microscope of the present invention. FIG. 2b is a diagram of FIG.
FIG. 4 is a diagram showing an electrical operation of the array of FIG.

In the optical arrangement diagram of FIG. 1, 1 is a laser light emitting device, 2 and 3 are beam expanders, and 4 is an AOD device, which uses anisotropic Bragg diffraction. The laser beam from the laser light emitting device 1 is polarized in the direction of deflection in the AOD device 4. When the polarized light is deflected in the X direction by the AOD device 4, the polarization plane is rotated by 90 ° and enters the PBS device 6 via the cylinder lens 5. The light incident on the PBS device 6 is S-polarized light, reflected by the PBS device 6, and transmitted through the pupil transmission optical system 7,
8, a galvanomirror device 9 for scanning in the Y direction
Incident on.

The optical axes 1 to 6 of this optical system are actually perpendicular to the plane of the paper, but are drawn in the same plane for convenience of drawing. Then, the light is deflected in the Y direction by a mirror 9, passes through a / 4λ plate 10, and is focused by an imaging lens 11 on an image forming point F of a sample image formed by an objective lens 12. The focused beam forms a spot on the sample 13 by the objective lens 12. The AOD device 4 scans the spot at high speed in the X direction or GMD
Scanning is performed in the Y direction at low speed by the device 9 to form a two-dimensional scanning format.

The imaging lens 11 is arranged to form a reflection surface image of the galvanometer mirror 9 at the entrance pupil position of the objective lens 12.

The sample 13 can be visually observed by the naked eye 33 via the prism 31 and the eyepiece 32, but is retracted outside the optical path during beam scanning.

The light beam incident on the sample 13 reflects, scatters, or induces fluorescence. These lights return to the PBS device 6 via the same path. Due to the function of the λ / 4 plate 10, the return light has the deflection surface rotated by 90 ° and passes through the PBS device 6 as a P-wave. The transmitted light is collected by a lens 14 and focused on a detector 15 which is a photoelectric conversion element array. A slit 34 having an opening in the X direction is provided on the front surface of the detector 15 as necessary. On the detector 15, the return light is scanned in the X direction according to the scanning of the AOD device 4, but the array arrangement direction is a direction perpendicular to the paper surface. Next, the operation of the detector 15 will be described. Synchronous controller 16
Then, an X and Y direction synchronizing signal is generated, and further a clock signal (see 26 in FIG. 2B) is generated in synchronization with the X direction synchronizing signal and according to the X direction scanning speed. The drive control circuit 17 receives the clock signal and receives a gate control signal (FIG. 2B).
27), and the gate control signal causes the detector 15 to change the scanning point on the sample according to the scanning speed in the X direction,
The light receiving pixels are read out in a conjugate manner. The read signal (see 29 in FIG. 2B) is subjected to an image operation by the image memory and the image processing means 18 and displayed on the display means 19. Also, the X generated by the synchronization controller 16
And the Y-direction synchronization signal, the A
The OD device 4 is driven, and although not shown, the GMD device 9 is also synchronously controlled.

The returning light is transmitted from between the lens 8 and the GMD device 9 to the PBS device 6.
Can also be taken out. Or, when making an image by transmitted light, with a collector lens and a mirror system,
When the transmitted light is returned to the GMD device 9, there is no problem of synchronization between the two types of Y deflection mirrors.

With such a configuration, an image is formed by performing optical scanning on the sample. Means for achieving confocal using the photoelectric conversion element array 15 will be described with reference to FIGS.

FIG. 2a is a schematic view of a part of the photoelectric conversion element array,
It shows a part of the one-dimensional arrangement of the number of pixels corresponding to the field of view.

In the figure, reference numerals 20-a, b, c, and d denote photodiodes as photoelectric conversion elements, each of which is electrically and optically independent. Also, the photodiode 20-a,
The light receiving area of b, c and d is about the spot diameter focused by the lens 14. The spot diameter depends on the lens
Depending on the focal length of 14, the spot diameter can be selected appropriately. Further, if necessary, a stop 34 having an opening corresponding to each pixel can be received at the focal position of the lens 14 through the opening immediately before the detector 15. Also, the photodiodes 20-a, b,
As for c and d, each anode or cathode is commonly connected to the substrate, and the other end of the cathode or anode is externally connected. The outside is commonly connected to two independent analog switches 21-a, b, c, d and 22-a, b, c, d for each pixel. After passing through the analog switches 21 and 22, the pixel signal lines are connected in common, and those passing through the switch 21 are output to the outside via an amplifier 23 as signals. Those that have passed through the switch 22 are connected to a common substrate, and short-circuit the photoelectric conversion element 20. 24 is an analog switch 21 and 25 is an analog switch
Each shift register outputs a signal for controlling the opening and closing of 22. The shift registers 24 and 25 transmit the 1 and 0 signals input from the drive control circuit 17 by the clock 26 (see FIG. 2B) sent from the control circuit 17 in response to the X-direction scanning. Then, the analog switches 21 and 22 are controlled.

As described above, the driving means used in the present invention includes 17, 21, 2
2, 24 and 25.

FIG. 2b shows the timing of the operation.
26 is a drive clock for the shift registers 24 and 25. One cycle of the clock corresponds to one pixel of the light receiving unit 20. Now, in the spot image in the confocal system, in the considered coherent system, a high-order ring 30-b surrounding the central peak 30-a is generated in addition to the central peak 30-a as shown by the curve 30. If only the central peak 30-a can be extracted, an image with high resolution can be obtained, but if a higher-order ring of 30-b is also received, it becomes an incoherent system, and there is no difference from a normal optical microscope. The Y direction is the light receiving section 20
Is confocal because of the
With respect to the direction, the conventional method cannot receive confocal light because it receives a higher-order ring light of 30-b.

That is, a switch 21 for taking out a signal and a switch 22 for short-circuiting the photodiode 20 of the light receiving section are transmitted by the shift registers 24 and 25 as signals shown as gate control signals 27 and 28, respectively. By extracting a signal corresponding to a point, a confocal system in the X direction can be realized.

Analog switches 21 and 22 are described as switches that are closed by positive [1] control. Here, it is assumed that the scanning point on the sample now corresponds to 20-b. The scanning point on the sample and the light receiving unit pixel 20-b are
Have a conjugate relationship, and the other pixels 20-a, b,
It is not conjugate with the others of c and d. At this time, the positive pulse sent by the shift register 24 closes only the analog switch 21-b, and the photoelectric conversion signal of 20-b is extracted to the outside via the amplifier 23. At this time, the switch 22-b is opened by the negative pulse 28 sent from the shift register 25. Of the analog switches corresponding to pixels other than 20-b, 21-
a, c, d and others are open, and 22-a, c, d, etc. are closed. Higher-order ring light of a spot centered at 20-b is generated by surrounding photoelectric conversion elements 20-a, c, and d.
In addition, although incident, this photoelectric conversion element group is short-circuited by the analog switches 22-a, c, d, and the like. Because it is insulated, it does not contribute to the signal to the outside, and because there is no accumulation effect in the photoelectric conversion unit,
A detection signal as indicated by 29 solid lines corresponding to confocal is obtained. The dotted line 29 indicates the signal of each of the other pixels.

On the other hand, when a conventional storage-type PSCD or CCD is used, a light-receiving unit and a shutter array using the liquid crystal or electro-optic effect in which the openings correspond one-to-one are connected to the condenser lens 14. A similar effect can be obtained by arranging the shutter on the focal plane and opening the shutter in synchronization with the X scanning.

The signals obtained by the beam scanning and output to the outside by the array and the circuit are displayed on an image display device 19 after being converted and stored by an image processing device 18.
The beam scanning image is displayed on the display device 19.
The image can be hard copied by recording means such as a video printer.

[Effects of the Invention] The following remarkable technical effects were obtained by the scanning optical microscope according to the present invention.

Each pixel of the used photoelectric conversion element corresponds to each scanning point on the X scanning line on the sample, and light from outside the corresponding scanning point is:
By short-circuiting the photoelectric conversion unit, connecting the photoelectric conversion unit only at the corresponding scanning point to an external circuit, and extracting the information, each pixel also functions as a pinhole in the X direction as well as in the Y direction, An excellent scanning optical microscope that can be configured into an ideal confocal system could be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an optical arrangement of a scanning optical microscope of the present invention. FIGS. 2a and 2b are a schematic diagram of an optical conversion element array used in the scanning optical microscope of the present invention and a timing chart showing electrical operations thereby. [Description of Signs of Main Parts] 1 Laser light source device 4 AOD using anisotropic Bragg diffraction 6 PBS 9 GMD 15 Optical conversion element array (detector) 17 Drive control circuit 18 ... Image processing means 20-a, b, c, d ... Photodiodes 21-a, b, c, d which are part of the light receiving section of the photoelectric conversion element array ... Analog switches 22-a for extracting signals b, c, d: switch for short-circuiting the photoelectric conversion element 23: amplifier circuit 24, 25 shift register 26 clock signal 27, 28 timing signal 29 detection signal F: objective lens 11 Sample image point

Claims (1)

(57) [Claims] 1. A two-dimensional scan of a sample from a coherent light source through an objective lens is performed by using an acousto-optic deflecting element to rapidly scan light in the X direction, and by using a galvanomirror deflecting element to slowly scan light in the Y direction. In a coherent light scanning optical microscope apparatus having a light receiving element that receives a return light or a transmitted light from the sample and converts it into a video signal, the light receiving elements are arranged in the X direction, and are conjugated to scanning points in the X direction on the sample. A driving means for driving the corresponding array so as to obtain only information on scanning points on a sample corresponding to each pixel of the photoelectric conversion element array. A drive control circuit that outputs a gate control signal synchronized with the X-direction scanning; a shift register that outputs the gate control signal for each pixel in response to the X-direction scanning; One pixel for each pixel which is arranged corresponding to each pixel of the photoelectric conversion element array and which is controlled by the shift register so as to read out only the pixel corresponding to the scanning point and short-circuit the other pixels so as to be short-circuited. A coherent light-scanning optical microscope device essentially comprising a pair of analog switches.