CN1176367C - Automatic focusing device of laser confocal scanner - Google Patents

Abstract

The present invention relates to an automatic focusing device of a laser confocal scanner, which belongs to the field of photoelectric detection devices for biological instruments, medical care instruments and scientific instruments. The present invention is characterized in that the automatic focusing device comprises an optical head, an input optical path, a reflecting optical path for focusing and a reflecting optical path for detection, wherein the input optical path is orderly composed of a laser device, a needle hole, a lens, an objective lens and a sample; the reflecting optical path for focusing is composed of the sample, the objective lens, a beam splitter mirror, an astigmatic lens and a quadrant photoelectric detector; the reflecting optical path for detection is orderly composed of the sample, the objective lens, a dichroic beamsplitter, the lens, the needle hole and a photomultiplier tube; the focusing control circuit is a digital control circuit which is mainly composed of a digital signal processor, a computer and an actuating motor; the focusing mechanism is a screw rod-nut type focusing mechanism connected with the output axis of an actuating circuit, and meanwhile, the automatic focusing device is provided with a photoelectric control type limit switch. The automatic focusing device can detect biological samples in an automatic focusing mode and has the advantages of large focusing range and high precision.

Description

Automatic focusing device of laser confocal scanner

technical field

An automatic focusing device of a laser confocal scanner belongs to the field of photoelectric detection devices for biological, medical and scientific instruments.

Background technique:

Compared with ordinary microscopes, laser confocal scanners have higher resolution and are widely used in biological, life, medical and scientific instruments. The existing focusing techniques and devices, which are developed for different technical fields, cannot be fully applied to laser confocal scanners. For example, the Chinese utility model patent No. ZL98229444.1, named "Focusing device for submicron lithography machine", discloses a focusing device for lithography machine, which is characterized in that: the marked imaging light passes through the object to be engraved , a small objective lens, and a reflector, it is divided into two paths by a beam splitter, one path is reflected and imaged on a four-quadrant receiver, the other path is transmitted through a cylindrical mirror and imaged on a CCD image sensor, and the two paths output defocus signals and target offsets to send Into the single chip microcomputer, control the piezoelectric ceramics to push the flexible hinge, and drive the object to be engraved to make a large displacement or a small displacement to reach the target focal plane position. It does not have a reflected optical path for detection and is not suitable for use in laser confocal scanners.

purpose of invention

The object of the present invention is to provide an automatic focusing device of a laser confocal scanner.

The present invention is characterized in that: the automatic focusing device of the laser confocal scanner includes a confocal optical path and a focusing optical path, a focusing control circuit and a focusing mechanism, and is characterized in that:

Described confocal optical path and focusing optical path contain successively by laser 1, first pinhole 2, lens 3, two dichroic beam splitters (4,5) that form 45 ° angle with optical axis, objective lens 6 and The incident optical path formed by the sample 8, wherein the laser 1 is close to the first pinhole 2, the first pinhole 2 is placed on the front focal plane of the lens 3, and the sample 8 is placed on the back focal plane of the objective lens 6;

Along the optical path of the laser light reflected from the sample and the excited fluorescence, the objective lens 6, the dichroic beam splitter 5, the lens 3, the pinhole 2 and the photomultiplier tube 10 are sequentially arranged, wherein the The photomultiplier tube 10 is placed close to the second pinhole 2, and the second pinhole 2 is placed on the rear focal plane of the lens 3, and this path is a confocal optical path;

Along another optical path that is passed by the laser light reflected from the sample and the excited fluorescence, the objective lens 6, the two dichroic beam splitters 5, 4, the astigmatic lens 11 and the four-quadrant photodetector are sequentially arranged. device 12, wherein the four-quadrant photodetector 12 is placed on the back focal plane of the astigmatic lens 11, and this path is a reflective focusing optical path;

The focus control circuit is made up of the following parts: the four-quadrant photodetector 12 produces four-way electrical signal output, and the input terminal is connected to the four-way electrical signal output end of the four-quadrant photodetector 12. The filter circuit 14 that is connected with the output end of the above-mentioned amplifying circuit 13, the analog-to-digital conversion circuit 15 that the input end is connected with the output end of the above-mentioned filter circuit (14), the digital signal processor 16 that the input end is connected with the output end of the above-mentioned analog-to-digital conversion circuit 15 , the photoelectric isolation module circuit 18 whose input end is connected to the output end of the above-mentioned digital signal processor 16, the digital-to-analog conversion circuit 19 whose input end is connected to the output end of the above-mentioned photoelectric isolation module circuit 18, and the input end is connected to the output end of the above-mentioned digital-to-analog conversion circuit 19 Connected motor drive power amplifying circuit 20, the execution motor 21 whose input terminal is connected to the output end of the above-mentioned motor driving power amplifying circuit 20, and the computer 17 whose input interface is connected to the output end of the above-mentioned digital signal processor 16;

The focusing mechanism is a lead screw-nut type mechanical focusing mechanism connected with the output shaft of the executive motor.

The present invention is also characterized in that:

Described confocal optical path and focusing optical path contain successively by laser 1, first pinhole 2, lens 3, two dichroic beam splitters (4,5) that form 45 ° angle with optical axis, objective lens 6 and The incident optical path formed by the sample 8, wherein the laser 1 is close to the first pinhole 2, the first pinhole 2 is placed on the front focal plane of the lens 3, and the sample 8 is placed on the back focal plane of the objective lens 6;

Along the optical path of the laser light reflected from the sample 8 and the excited fluorescence, the objective lens 6, the dichroic beam splitter 5, the lens 3, the pinhole 2 and the photomultiplier tube 10 are sequentially arranged, wherein the The photomultiplier tube is placed close to the second pinhole 2, and the second pinhole 2 is placed on the rear focal plane of the lens 3, and this path is a confocal optical path;

Along the optical path of the laser light transmitted from the sample and the excited fluorescence, the following are arranged in sequence: an objective lens 6, a mirror 4, an astigmatic lens 11, and a four-quadrant photodetector 12, wherein the four-quadrant photodetector 12 is placed on the rear focal plane of the astigmatic lens 11, and this path is a transmissive focusing optical path;

The focus control circuit is made up of the following parts: the four-quadrant photodetector 12 produces four-way electrical signal output, and the input terminal is connected to the four-way electrical signal output end of the four-quadrant photodetector 12. The filter circuit 14 that is connected with the output end of the above-mentioned amplifying circuit 13, the analog-to-digital conversion circuit 15 that the input end is connected with the output end of the above-mentioned filter circuit (14), the digital signal processor 16 that the input end is connected with the output end of the above-mentioned analog-to-digital conversion circuit 15 , the photoelectric isolation module circuit 18 whose input end is connected to the output end of the above-mentioned digital signal processor 16, the digital-to-analog conversion circuit 19 whose input end is connected to the output end of the above-mentioned photoelectric isolation module circuit 18, and the input end is connected to the output end of the above-mentioned digital-to-analog conversion circuit 19 Connected motor drive power amplifying circuit 20, the execution motor 21 whose input terminal is connected to the output end of the above-mentioned motor driving power amplifying circuit 20, and the computer 17 whose input interface is connected to the output end of the above-mentioned digital signal processor 16;

The focusing mechanism is a lead screw-nut type mechanical focusing mechanism connected with the output shaft of the executive motor.

It is also characterized in that: in the mechanical focusing mechanism, the actuator motor 21 is fixed on one end of the motor mounting plate 26, and the other end of the motor mounting plate 26 is fixed on the upper part of the fixed mounting plate 24, and the actuator motor 21 is connected through a shaft The device 30 is fixedly connected with the screw 22, and the screw 22 is connected with the screw bracket 23 and the screw nut 29 at the same time, and the other end of the screw bracket 23 is fixed on the fixed mounting plate 24, and the screw nut 29 is fixed on one end of movable base plate 27, and the other end of described movable base plate 27 fixes lens 6 through objective lens cover 7, and described movable base plate 27 is fixedly connected with movable guide rail 28, and described movable guide rail 28 links to each other with fixed slider 25, so The fixed slider 25 is provided with a photoelectric sensor 31 , and the other end of the fixed slider 25 is fixed to the bottom of the fixed mounting plate 24 . The executive motor drives the lead screw to rotate through the coupling, so that the lead screw nut moves up and down along the lead screw, and moves the animal mirror cover and the objective lens up and down along the optical axis until the sample Reach the required target focal plane position to complete the purpose of focusing. The photoelectric sensor plays the role of positioning and limiting, and avoids collision between the lens and the sample.

Proof of use: It served its intended purpose.

Description of drawings

Figure 1 and Figure 2: Optical path diagrams of two embodiments of optical system devices in a laser confocal scanner.

Figure 3: Circuit schematic block diagram of the focus control circuit.

Figure 4: Mechanical block diagram of the screw-nut type focusing mechanism.

Detailed ways:

Please see Figure 1. The laser 1 is close to the pinhole 2, and the pinhole 2 is placed on the front focal plane of the lens 3. The laser beam is projected to the lens 3 through the pinhole 2 and becomes parallel light, and passes through the dichroic beam splitter 4, which forms an angle of 45° with the optical axis. The dichroic beam splitter 5 and the objective lens 6 with large numerical aperture focus and image vertically onto the sample 8, the objective lens 6 is fixed on the objective lens holder 7, the sample 8 is placed on the sample holder 9, the sample 8 is excited to emit fluorescence, and the laser is Scattering occurs, forming two paths of light: reflected light and transmitted light, each path of light is composed of laser light and excited fluorescence.

In the reflected light path, the reflected light passes through the objective lens 6 and becomes parallel light, and after reaching the dichroic beam splitter 5, it is split again to form reflected light and transmitted light. In the reflected light path, the reflected light is the fluorescence excited from the sample, which is reflected by the dichroic beam splitter 5 to the lens 3, focused and imaged to the pinhole 2 in front of the photomultiplier tube, and is captured by the light close to the pinhole 2 Telecom tube 10 detects that this path of light is the confocal light path; in the transmitted light path, the transmitted light is the laser light reflected from the sample, passes through the dichroic beam splitter 5, and is projected onto the dichroic beam splitter 4, where it is split again , wherein the reflected light is reflected onto the astigmatic lens 11 and converged onto the four-quadrant photodetector 12 . By properly selecting the focusing parameters in the two directions of the astigmatic lens 11 , a certain focusing range and a certain focusing precision can be obtained.

In the transmitted light path, the transmitted light passes through the sample.

Goodbye Figure 2. The laser 1 is close to the pinhole 2, and the pinhole 2 is placed on the front focal plane of the lens 3. The laser beam is projected to the lens 3 through the pinhole 2 and becomes parallel light, and then passes through the dichroic beam splitter 5 at an angle of 45° to the optical axis. The objective lens 6 with large numerical aperture is focused and imaged on the sample 8 vertically, the objective lens 6 is fixed on the objective lens holder 7, the sample 8 is placed on the sample holder 9, the sample 8 is excited to emit fluorescence, and the laser light is also scattered here, forming two Path light: reflected light and transmitted light, each path of light is composed of laser light and excited fluorescence. In the transmitted light path, the transmitted light passes through the objective lens 6 and the reflecting mirror 4, and finally reaches the astigmatic lens 11 and is imaged on the four-quadrant photodetector 12. When the focusing parameters of the two directions of the astigmatic lens 11 are selected, a certain adjustment can be obtained. Focus range and certain focus accuracy.

Goodbye Figure 3. The four-quadrant photodetector 12 divides a beam of light converging on it into four areas for detection, and obtains four electrical signal outputs, and enters a digital signal processor 16 and a computer 17 through an amplifier 13, a filter 14 and an analog-to-digital converter 15, Calculate and store the defocus information of the sample point. According to the defocus information, the digital signal processor 16 or the computer 17 sends out an automatic focus command, and the execution motor 21 is driven by the photoelectric isolation module 18, the digital-to-analog converter 19 and the motor drive power amplifier circuit 20, and the focus mechanism is driven to perform focusing.

In Fig. 4, the actuator motor 21 in the focusing mechanical mechanism is fixed on one end of the motor mounting plate 26, and the other end of the motor mounting plate 32 is fixed on the upper part of the fixed mounting plate 24, and the actuator motor 21 is passed through a coupling 30 is fixedly connected with the screw 22, and the screw 22 is connected with the screw bracket 23 and the screw nut 29 at the same time, and the other end of the screw bracket 23 is fixed to the middle part of the fixed mounting plate 24, and the screw nut 29 is fixed on one end of movable base plate 27, and the other end of described movable base plate 27 fixes lens 6 by objective lens holder 7, and the middle part of described movable base plate 27 is fixedly connected with movable guide rail 28, and described movable guide rail 28 is connected with fixed slider 25, the fixed slider 25 has a photoelectric sensor 31, and the other end of the fixed slider 25 is fixed to the bottom of the fixed mounting plate 24. In this way, the motor 21 drives the lead screw 22 to rotate through the shaft coupling 30, so that the lead screw nut 29 moves up and down along the lead screw 22, and drives the objective lens cover 7 and the objective lens 6 to move up and down along the optical axis until the sample 8 reaches the required objective lens. 6 Back focal plane position, complete focusing. The photoelectric sensor 31 plays the role of positioning and limiting, and prevents the lens 6 and the sample 8 from colliding with each other.

It can detect samples by automatic focusing, and has the advantages of large focusing range and high precision.

Claims (3)

1, the automatic focusing device of laser cofocal scanner contains confocal light path and focusing light path, and focusing control circuit and focus adjusting mechanism is characterized in that:

Described confocal light path and focusing light path contain successively by laser instrument (1), first pin hole (2), lens (3), two input path with dichroic beamsplitter (4,5), object lens (6) and sample (8) formation at optical axis angle at 45, wherein laser instrument (1) is near first pin hole (2), first pin hole (2) is positioned on the front focal plane of lens (3), and sample (8) is placed on the back focal plane of object lens (6);

Along what the light path from sample laser light reflected and the fluorescence institute approach that inspires set gradually be: described object lens (6), described dichroic beamsplitter (5), lens (3), second pin hole (2) and photomultiplier (10), wherein said photomultiplier (10) and second pin hole (2) are near placement, described second pin hole (2) is positioned on the back focal plane of lens (3), and this road is confocal light path;

Along what another light path from sample laser light reflected and the fluorescence institute approach that inspires set gradually be: described object lens (6), described two dichroic beamsplitters (5,4), astigmatic lens (11) and four-quadrant photo detector (12), wherein said four-quadrant photo detector (12) is placed on the back focal plane of astigmatic lens (11), and this road is reflective focusing light path;

Focusing control circuit is made of following each several part: four-quadrant photo detector (12) produces the output of four road electric signal, the amplifying circuit (13) that input end is connected with four road electrical signals of described four-quadrant photo detector (12), the filtering circuit (14) that input end links to each other with above-mentioned amplifying circuit (13) output terminal, the analog to digital conversion circuit (15) that input end links to each other with above-mentioned filtering circuit (14) output terminal, the digital signal processor (16) that input end links to each other with above-mentioned analog to digital conversion circuit (15) output terminal, the photoelectric isolation module circuit (18) that input end links to each other with above-mentioned digital signal processor (16) output terminal, the D/A converting circuit (19) that input end links to each other with above-mentioned photoelectric isolation module circuit (18) output terminal, the motor-driven power amplification circuit (20) that input end links to each other with above-mentioned D/A converting circuit (19) output terminal, the actuating motor (21) that input end links to each other with above-mentioned motor-driven power amplification circuit (20) output terminal, and the computing machine (17) that links to each other with above-mentioned digital signal processor (16) output terminal of input interface; Focus adjusting mechanism is the leading screw one nut type mechanical focusing mechanism of joining with the actuating motor output shaft.

2, the automatic focusing device of laser cofocal scanner contains confocal light path and focusing light path, and focusing control circuit and focus adjusting mechanism is characterized in that:

Described confocal light path and focusing light path contain successively by laser instrument (1), first pin hole (2), lens (3), two input path with dichroic beamsplitter (4,5), object lens (6) and sample (8) formation at optical axis angle at 45, wherein laser instrument (1) is near first pin hole (2), first pin hole (2) is positioned on the front focal plane of lens (3), and sample (8) is placed on the back focal plane of object lens (6);

Along what the light path from sample (8) laser light reflected and the fluorescence institute approach that inspires set gradually be: described object lens (6), described dichroic beamsplitter (5), lens (3), pin hole (2) and photomultiplier (10), wherein said photomultiplier and second pin hole (2) are near placement, described second pin hole (2) is positioned on the back focal plane of lens (3), and this road is confocal light path;

Along what the light path from the laser of sample transmission and the fluorescence institute approach that inspires set gradually be: object lens (6), catoptron (4) and astigmatic lens (11), and four-quadrant photo detector (12), wherein said four-quadrant photo detector (12) is placed on the back focal plane of astigmatic lens (11), and this road is a transmission-type focusing light path;

Focusing control circuit is made of following each several part: four-quadrant photo detector (12) produces the output of four road electric signal, the amplifying circuit (13) that input end is connected with four road electrical signals of described four-quadrant photo detector (12), the filtering circuit (14) that input end links to each other with above-mentioned amplifying circuit (13) output terminal, the analog to digital conversion circuit (15) that input end links to each other with above-mentioned filtering circuit (14) output terminal, the digital signal processor (16) that input end links to each other with above-mentioned analog to digital conversion circuit (15) output terminal, the photoelectric isolation module circuit (18) that input end links to each other with above-mentioned digital signal processor (16) output terminal, the D/A converting circuit (19) that input end links to each other with above-mentioned photoelectric isolation module circuit (18) output terminal, the motor-driven power amplification circuit (20) that input end links to each other with above-mentioned D/A converting circuit (19) output terminal, the actuating motor (21) that input end links to each other with above-mentioned motor-driven power amplification circuit (20) output terminal, and the computing machine (17) that links to each other with above-mentioned digital signal processor (16) output terminal of input interface; Focus adjusting mechanism is the leading screw-nut type mechanical focusing mechanism of joining with the actuating motor output shaft.

3, the automatic focusing device of laser cofocal scanner according to claim 1 and 2, it is characterized in that: actuating motor (21) is fixed on motor mounting plate (26) one ends in the described mechanical focusing mechanism, the other end of described motor mounting plate (26) is fixed on mounting plate (24) top, described actuating motor (21) is fixedlyed connected with leading screw (22) by shaft joint (30), described leading screw (22) links to each other with feed screw nut (29) with leading screw support (23) simultaneously, described leading screw support (23) other end is fixed on the described mounting plate (24), described feed screw nut (29) is fixed on removable bottom (27) one ends, the other end of described removable bottom (27) is by object lens cover (7) fixed lens (6), described removable bottom (27) is fixedlyed connected with movable guiding rail (28), described movable guiding rail (28) links to each other with fixing slide block (25), have photoelectric sensor (31) on the described fixedly slide block (25), described fixedly slide block (25) other end is fixed to described mounting plate (24) bottom.

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