JP2003195182A - Condensing optical system and particle manipulation device - Google Patents

Abstract

(57) Abstract: A condensing optical system capable of continuously and largely changing the spherical aberration of a generated conical condensed light beam, and a sufficient light having such a condensing optical system Provided is a particle manipulation device capable of capturing and manipulating a sample by force. Further, the present invention provides a particle manipulation device capable of observing particles with good contrast in an observation optical system. SOLUTION: A condensing optical system is provided by providing a liquid cell capable of arbitrarily changing the length in the optical path direction in an optical path of a condensed light beam. In addition, a fine particle manipulation device including such a condensing optical system is configured, and by changing the length of the liquid cell in the optical path direction, a continuous and arbitrary spherical aberration is generated in the condensed light beam passing through the liquid cell. Generate and capture and manipulate fine particles. Further, the particle manipulation device is configured such that the spherical aberration of the converged light beam and the focus position in the optical axis direction can be arbitrarily and independently changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a condensing optical system for generating a conical condensed light beam. Further, the present invention relates to a fine particle manipulation device that traps or moves the fine particles three-dimensionally by irradiating the fine particles with a conical focused light flux generated by such a focusing optical system.

[0002]

2. Description of the Related Art Manipulation of fine particles by light is generally called optical tweezers or an optical trap. Since a laser is mainly used as a light source, it is also called laser trapping or laser tweezers. In this method, laser light from a light source is condensed into a conical shape by a condensing optical system and is irradiated to the vicinity of the fine particles in a medium, and the radiation pressure of the light generated in the fine particles is used to capture the fine particles. It is held or moved, and is used in various ways as a method for capturing and manipulating living cells and microorganisms in a non-contact and non-destructive manner.

As shown in FIG. 4, a parallel light flux L1 for optical tweezers emitted from a light source LS1 for optical tweezers.
Reference numeral 1 denotes a conical focused light flux which is reflected by the dichroic mirror DM in a wavelength-selective manner, enters a focusing optical system O3 having a normal spherical aberration of substantially zero, and passes through the focusing optical system O3 without spherical aberration. L13 irradiates the vicinity of the fine particles S in the medium B held in the holder H such as a petri dish or a slide glass. Then, as shown in FIG. 5, when the fine particles S are present in the vicinity of the condensing point P condensed by the condensing optical system O3 in a conical shape, the conical condensed light flux L13 is formed on the surface of the fine particles S. The traveling direction changes due to reflection or refraction inside the fine particles S, and as a result, the momentum of the light flux changes. At this time, a radiation pressure is generated on the fine particles S according to a change in momentum of the condensed light beam L13, and a force F as indicated by a thick solid arrow in the drawing acts.

If the fine particles S are spherical fine particles having a refractive index higher than that of the surrounding medium B and no absorption, the radiation pressure has a high light intensity based on the analysis of the momentum change of the condensed light flux. It is known that a force F that acts on one side and is attracted to the condensing point P acts. Therefore, it is possible to capture and operate the fine particles S by using this force F. Further, when capturing and operating the fine particles S in the medium B in this way, it is necessary to observe the state, and for that reason, an observation optical system is provided. That is, the light flux L2 for irradiation emitted from the observation light source LS2 installed below the holder H passes through the illumination optical system C1 and illuminates the entire area in the vicinity of the fine particles S in the medium B, and then is condensed. It passes through the optical system O3, passes through the dichroic mirror DM, and is imaged on the image plane IMG. And this image plane IMG
By observing the magnified image of the fine particles S formed on the image with the naked eye E through the image pickup means D such as a CCD camera or the eyepiece EP, it is possible to observe how the fine particles S in the medium B are captured and operated. It will be possible.

[0005]

However, in the above-mentioned conventional optical tweezers, a force for trapping fine particles in the axial direction along the traveling direction of the condensed light flux for the optical tweezers, that is, in the optical axis direction (hereinafter, this fine particle will be described). The trapping force is called "trapping force") is much smaller than the trapping force in the direction perpendicular to the optical axis direction, and its range is limited. There was a problem that it was difficult to capture. For example, when capturing fine particles in a medium composed of a liquid such as water through a cover glass, an objective lens for biological observation that is actually often used as a focusing optical system of optical tweezers has a spherical aberration on the lower surface of the cover glass. It is adjusted so that it becomes almost zero, and if a light beam is focused deep inside the medium below the cover glass, negative spherical aberration will occur when passing through the medium. The maximum trapping force obtained with optical tweezers became weaker as the position in the medium deepened. A similar situation occurs when capturing molecules at deep positions inside the thick biological sample instead of near the surface. Furthermore, although the spherical aberration of the objective lens is almost zero on the lower surface of the cover glass, it is
Since a small amount of spherical aberration often remains, even when trapping fine particles at the same depth in the medium, the aberration differs depending on the objective lens used, and as a result, the trapping force is different and the trapping force is not stable. There was also a problem.

Further, in the above-mentioned conventional optical tweezers, since there is axial chromatic aberration in the converging optical system, the converging position of the converging light beam for the optical tweezers and the optical axis direction in the observation optical system. It often did not always match the in-focus position. As a result, even if an attempt is made to observe the fine particles captured by the optical tweezers with the observation optical system, the position of the fine particles in the optical axis direction deviates from the focus position in the optical axis direction of the observation optical system, and the contrast is lowered. There is a problem that the fine particles are out of focus and are difficult to observe. In some cases, when the amount of displacement is larger, the fine particles cannot be observed at all.

The present invention has been made in view of these problems, and a condensing optical system capable of continuously and significantly changing the spherical aberration of the generated conical condensed light beam, and such a condensing optical system. An object of the present invention is to provide a particle manipulation device having an optical optical system and capable of capturing and manipulating a sample (particle) with sufficient force. Another object of the present invention is to provide a fine particle manipulating device capable of observing fine particles with good contrast in an observation optical system.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies based on such a background, and as a result, have found means for solving the above problems. A condensing optical system according to the present invention, that is, a condensing optical system according to claim 1, is a condensing optical system that generates a conical condensing light beam. By providing a liquid cell that can be changed arbitrarily and changing the length of the liquid cell in the optical path direction, continuous and arbitrary spherical aberration is generated in the condensed light flux passing through the liquid cell. It is characterized by Here, the liquid cell is a liquid cell in which a liquid is enclosed in an expandable / contractible enclosure (container), and the liquid enclosed in the enclosure includes a gel type.

Further, a fine particle manipulating apparatus according to the present invention, that is, a fine particle manipulating apparatus described in claim 2, has a condensing optical system for generating a conical condensing light beam, and the condensing light beam is a fine particle in a medium. A fine particle manipulation device for capturing and manipulating fine particles by irradiating the same with the condensing optical system according to the present invention, wherein the condensing light beam continuously and arbitrarily generates spherical aberration to trap and manipulate the fine particles. Is characterized by. Claim 3
The fine particle manipulation apparatus according to claim 2 is the fine particle manipulation apparatus according to claim 2, wherein the observation optical system for observing the fine particles includes a part of a focusing optical system, and the focusing optical system focuses on the observation optical system. It is characterized in that a correction mechanism for correcting the position is provided.

Further, another particle manipulating device according to the present invention, that is, a particle manipulating device according to a fourth aspect, has a condensing optical system for generating a conical condensed light beam, and the condensed light beam is a medium. Capture the particles by irradiating the particles inside
The fine particle operating device to be operated is characterized in that the spherical aberration of the condensed light beam and the focus position in the optical axis direction can be arbitrarily and independently changed. Further, a fine particle manipulating apparatus according to a fifth aspect is the fine particle manipulating apparatus according to the fourth aspect, wherein the condensing optical system has a conjugate condensing point optically conjugate with a condensing point of the condensed light beam. A spherical aberration changing mechanism for changing the spherical aberration of the condensed light beam and a focus position changing mechanism for changing the focus position of the condensed light beam are provided in the vicinity of the conjugate light converging point.

Further, the fine particle manipulating apparatus according to a sixth aspect is the fine particle manipulating apparatus according to the fourth or fifth aspect, in which the focus position changing mechanism is installed oppositely in the optical path of the condensed light beam. It is characterized in that it is composed of a lens or a lens group having a refracting power of, and the focus position of the condensed light flux is changed by changing the interval between these lenses or the lens group. Further, the fine particle manipulation device according to claim 7 is the fine particle manipulation device according to claim 4 or 5, wherein the focus position changing mechanism has a positive refracting power that is installed to face the optical path of the condensed light flux. And a lens group having a negative refracting power and a lens or a lens group having a negative refracting power, and changing the distance between the lenses or the lens group to change the focus position of the condensed light beam. To do.

Further, in the fine particle manipulating apparatus described in claim 8, in the fine particle manipulating apparatus according to any one of claims 4 to 7, the spherical aberration changing mechanism is arranged in the optical path of the condensed light beam in the optical path direction. By having a liquid cell whose length can be changed arbitrarily, and by changing the length of the liquid cell in the optical path direction, continuous and arbitrary spherical aberration is generated in the condensed light flux passing through the liquid cell. It is characterized by being.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the first of the present invention.
FIG. 3 is a conceptual conceptual diagram of the particle manipulation device according to the embodiment of FIG. In FIG. 1, the parallel light flux L1 from the optical tweezers light source LS1 is given spherical aberration while passing through the focusing optical system O, and has a maximum NA with respect to the focusing point P of paraxial rays.
The component light becomes a condensed light flux having spherical aberration SA. By using the light flux having the spherical aberration SA, the fine particles S in the medium B are
To capture.

The condensing optical system O includes a first optical system O1 including an objective lens and a second optical system O1 for imparting spherical aberration to a light beam.
The optical system O2. Second, which imparts spherical aberration to the light flux
The optical system O2 includes a pair of lenses L for converging the light flux.
P1 and LP2 and a liquid cell LC arranged between these lenses LP1 and LP2. In the liquid cell LC, a liquid LQ such as water or oil is enclosed in a cell (encapsulation body) made of glass, plastic, or the like, and the distance d through which the parallel light flux L1 passes through the cell is arbitrarily and continuously changed. Is able to.

Further, as shown in FIG. 1, the fine particle manipulating apparatus according to this embodiment is provided with an observation optical system similar to that of the conventional example shown in FIG. That is,
The observation illumination light flux L2 emitted from the observation light source LS2 installed below the holder H is illuminated by the illumination optical system C1.
After illuminating the whole area in the vicinity of the fine particles S after passing through, the light is condensed by an optical system O2 including a microscope objective lens that constitutes a condensing optical system O that gives a positive spherical aberration SA.

Further, since the illumination light flux L2 for observation has a wavelength different from that of the light flux for optical tweezers emitted from the light source LS1 for optical tweezers, it is condensed by the optical system O2 and then is dichroic. It passes through the mirror DM without being reflected and forms an image on the image plane IMG. Then, the magnified image of the fine particles S formed on the image plane IMG is observed by the naked eye E through the image pickup means D such as a CCD camera or the eyepiece EP, so that the fine particles S in the medium B are captured and manipulated. It becomes possible to observe the situation.

2A and 2B are enlarged views of a concrete example of the liquid cell LC. In FIG. 2A, a part of the liquid cell LC is a bellows J, and the length d of the liquid cell LC can be changed by expanding and contracting the part. Further, FIG. 2B shows two cylindrical containers LC1 and L1.
A cell is formed by combining C2 so that the cylindrical portions partially overlap, and the liquid cell L is changed by changing the width of the overlapping portion x.
The length d of C can be changed. Overlapping part x
Is configured to have almost no gap so that liquid does not leak, or a gap between the two cylindrical containers LC1 and LC2 is filled with a high-viscosity gap sealant. In order to facilitate expansion and contraction in both FIGS. 2 (a) and 2 (b), the liquid LQ is not enclosed in the cell, but air is present in the upper part of the cell.
It is assumed that the cell has a sufficiently large size and the liquid LQ is sufficiently sealed so that the light flux can always pass only inside the liquid LQ. In this way, the distance that the parallel light beam L1 in FIG. 1 passes through the liquid cell LC can be arbitrarily changed, and as a result, the spherical aberration SA can be arbitrarily changed with respect to the parallel light beam L1.

A normal microscope objective lens can be used as the first optical system O1 shown in FIG. in this case,
Depending on the type and individual difference of the microscope objective lens, even if the depth in the medium B is the same, there occurs a difference in spherical aberration, and as a result, the force for capturing the sample (fine particles S) may be weak. Even in such a case, in the present fine particle manipulation device, the condensing optics provided with the liquid cell LC capable of arbitrarily changing the length in the optical path direction in the optical path of the generated conical condensed light flux. Has system O, second
By changing the length (length of the condensed light flux in the optical path direction) d of the liquid cell LC of the optical system O2, the spherical aberration of the high NA component of the trap light flux for illuminating the fine particles and the medium surrounding them is continuously changed. And because it can be changed significantly,
It is possible to correct the spherical aberration component due to the difference in the objective lens, and give the optimum spherical aberration for capturing the fine particles S regardless of the type of the objective lens used or the individual difference.

Here, the length (thickness) of the liquid cell is increased by providing a liquid cell in a portion where the light flux has a relatively large angle component and selecting a liquid having a high refractive index as the liquid to be sealed in the liquid cell. It is possible to further increase the amount of change in spherical aberration with respect to the change. Further, since the spherical aberration can be continuously changed, in the present fine particle manipulation device, even if the sample (fine particles) to be captured is at any medium depth position, the negative spherical aberration generated by the medium B surrounding the sample is obtained. Can be satisfactorily corrected. As a result, it becomes possible to impart appropriate spherical aberration to the condensed light flux in accordance with the depth of the fine particles S to be captured in the medium B, prevent the reduction of the capture power, and capture / manipulate the sample with sufficient force. .

In the fine particle manipulation device (optical tweezers) shown in FIG. 1, the first optical system O1 is commonly used as a magnifying lens of the observation optical system, but the second optical system O2 having a spherical aberration is used. Since it is provided in an optical path different from that of the observation optical system, it is not necessary to correct spherical aberration in the observation optical system. If the second optical system O2 having spherical aberration is shared with the observation optical system, it becomes necessary to separately correct the spherical aberration in the observation optical system.
If this is not done, spherical aberration is also imparted to the observed image, the contrast of the image is reduced, and a good image cannot be obtained. However, in this case as well, in order to observe the fine particles S with good contrast, it is desirable to provide the observation optical system with a correction mechanism (not shown) for correcting the focus position of the condensed light beam. This is because, if the size or material of the fine particles S, the depth of the fine particles S in the optical axis direction is different, or if the spherical aberration of the optical system O2 in the trapped condensed light flux is changed, the position of the fine particles S in the optical axis direction is held. This is because it is out of alignment.

As described above, in the present fine particle manipulation device, the observation optical system for observing the fine particles S includes a part or all of the above-mentioned focusing optical system O. Since a correction mechanism for correcting one or both of the spherical aberration and the focus position of the fine particles S is provided, the size and material of the fine particles S, the depth of the fine particles S in the optical axis direction, or the spherical aberration of the condensed light flux. Even if the position in the optical axis direction in which the fine particles S are held is deviated, the fine particles can be observed with good contrast by changing.

Further, in the fine particle manipulation device according to the present invention,
Since spherical aberration is not imparted to the objective lens itself, which is the condensing optical system, it is possible to impart arbitrary spherical aberration to the light beam before entering the objective lens. Even when the lens is commonly used as the imaging lens of the observation optical system, the problem that the observed image of the fine particles S is blurred and the contrast is not lowered does not occur.

In order to obtain a clear observation image with high contrast in the observation optical system of the above embodiment,
For example, the sample may be illuminated by using a dark field illumination method, an oblique illumination method, or the like, which is a conventional technique in the microscope observation method. Further, it is also possible to increase the contrast of the observed image by using a phase difference observation method or a differential interference observation method, which are also conventional techniques, in the observation optical system. Furthermore, confocal microscopes and near-field microscopes (NSO
It is also possible to configure the observation optical system by using a method such as M).

In the above embodiment, the wavelength-selective dichroic mirror DM is used as a means for dividing the optical paths of the focusing optical system for optical tweezers and the observation optical system. Other means may be used within the scope of the gist. For example, the light beams of the converging optical system for optical tweezers and the observation optical system may be made to have different polarization states using a polarizing plate or the like, and the polarization beam splitter may be used instead of the dichroic mirror DM to perform polarization splitting.

In the above embodiment, an optical system including a lens, a dichroic mirror and the like is shown as a means for guiding the light beam for optical tweezers and the illumination light beam for observation to the fine particles S, but the present invention is not limited to this. Instead, for example, an optical fiber may be used to guide the light flux for optical tweezers or the illumination light flux for observation. In this case, further miniaturization of the device can be expected.

Further, in the above embodiment, the observation optical system is shown as observing the magnified image of the fine particles S formed on the image plane IMG from above, but instead of such a method, for example, a downward microscope such as an inverted microscope is used. The method of observing from may be adopted.

In the above embodiment, the medium B in which the holder H holds the light beam for optical tweezers from above
As the fine particles S therein are irradiated, the incident direction of the light flux for optical tweezers on the medium B in which the fine particles S are present may be either the vertical direction. This also applies to the observation optical system. The incident direction of the light flux for these optical tweezers and the illumination light flux for observation and the combination thereof are
It is possible to freely arrange three-dimensionally within a range in accordance with the gist of the present invention.

Further, the liquid cell does not necessarily have the above-mentioned structure as long as the liquid is enclosed in an expandable container (container). The liquid sealed in the sealed body may be in the form of gel.

FIG. 3 shows a conceptual conceptual diagram of a particle manipulating apparatus according to a second embodiment of the present invention. Figure 3 (a)
3 is a schematic view of the apparatus, and FIG. 3B is a view of the turret constituting the apparatus shown in FIG.
In FIG. 3A, the parallel light flux L11 from the optical tweezers light source LS1 is given spherical aberration while passing through the condensing optical system O, and the focus position is adjusted so that the maximum NA component light has spherical aberration. The focused light flux L12 has SA and is focused at a predetermined focus position. The fine particles S are captured by using the light flux having the spherical aberration SA.

In FIG. 3A, the condensing optical system O condenses the light flux from the light source LS1 for optical tweezers and irradiates the first optical system O1 for irradiating the vicinity of the fine particles as the sample, and this light flux. It is composed of an optical system second O2 for changing the spherical aberration and the focus position. Further, the second optical system O2 for changing the spherical aberration and the focus position of the light flux temporarily condenses the parallel light flux L11 from the light source LS1 for optical tweezers at the point P ′, and a pair of lenses LP1 for expanding again. LP2
(Both of these two lenses LP1 and LP2 have positive refractive power) and a transparent parallel plate PT1 arranged between these lenses LP1 and LP2. At this time the first
Condensing point P of the light flux passing through the optical system O1 and the condensing point P ′
And are conjugate to each other.

As shown in FIG. 3 (a), the fine particle operating apparatus according to this embodiment is provided with an observation optical system similar to that of the conventional example shown in FIG. That is,
The observation illumination light flux L2 emitted from the observation light source LS2 installed below the holder H is illuminated by the illumination optical system C1.
After illuminating the whole area in the vicinity of the fine particles S after passing through, the light is condensed by an optical system O2 including a microscope objective lens that constitutes a condensing optical system O that gives a positive spherical aberration SA.

Further, since the illumination light flux L2 for observation has a wavelength different from that of the light flux for optical tweezers emitted from the light source LS1 for optical tweezers, after being condensed by the optical system O2, it is dichroic. It passes through the mirror DM without being reflected and forms an image on the image plane IMG. Then, the magnified image of the fine particles S formed on the image plane IMG is observed by the naked eye E through the image pickup means D such as a CCD camera or the eyepiece EP, so that the fine particles S in the medium B are captured and manipulated. It becomes possible to observe the situation.

Further, as shown in FIGS. 3 (a) and 3 (b), the parallel flat plate PT1 is incorporated in a turret T, and the turret T is rotated by rotating the turret T around a rotation axis Zt. Another parallel plate P having different characteristics such as thickness and refractive index from the other built-in parallel plates PT2 and PT3, that is, the parallel plate PT1.
It can be arbitrarily replaced with T2 and PT3.

Therefore, the parallel plate PT1 in the first optical system O1 for diverging the parallel light beam L11 from the light source LS1 for optical tweezers is replaced by the parallel plates PT2 and P2 having different characteristics.
By arbitrarily replacing with T3, the degree of divergence in the first optical system O1 is arbitrarily changed, and by extension, the magnitude of the spherical aberration SA imparted in the condensing optical system O is adjusted, and the refractive index of the fine particles S or It is possible to select the optimum spherical aberration SA according to conditions such as the depth in the optical axis direction to be trapped.

The lens LP2 is movable along the optical axis L (that is, the lens spacings LP1 and LP2 are variable), and the movement of the focal point P of the light beam in the optical axis direction, that is, the focus position. Can be moved.
That is, they are installed opposite to each other in the optical path of the condensed light flux L12,
The two lenses LP1 and LP2 having a positive refractive power form a focus position changing mechanism that changes the focus position of the condensed light beam L12. By changing the parallel plates PT1 to PT3, the condensing point (conjugate condensing point) P ′ is slightly moved in the optical axis direction, and the condensing point P is also moved.
This amount of movement can also be corrected by moving the lens LP2.

As described above, in the fine particle operating device shown in FIGS. 3A and 3B, the light source LS1 for optical tweezers is used.
The first optical system O1 for diverging the parallel light flux L11 from the optical system, more strictly speaking, the transparent thin parallel flat plate PT1 arranged between the two lenses LP1 and LP2 facing each other, imparts a positive spherical aberration SA to the spherical aberration. Function as a means of generation,
This parallel plate PT1 is used as another parallel plate PT with different characteristics.
The turret T, which can be arbitrarily replaced with 2, PT3, functions as a spherical aberration changing mechanism.

That is, the condensing optical system in the present fine particle manipulation device has a conjugate condensing point P'which is optically conjugate with the condensing point P of the conical condensing light beam L12, and this conjugate condensing point P '. A spherical aberration changing mechanism for changing the spherical aberration of the condensed light beam L12 and a focus position changing mechanism for changing the focus position of the condensed light beam L12 are provided in the vicinity of. In such a configuration,
The focus position changing mechanism moves the focus position of the condensed light flux L12 to a position where the observation image of the captured fine particles S can be observed with high contrast in the observation optical system, and further, the spherical aberration changing mechanism moves the focus light accompanying the focus movement. It is possible to suppress the spherical aberration state change of the light flux L12 and maintain the spherical aberration state optimum for capturing the fine particles S.

Therefore, in the present fine particle operating device, a predetermined spherical aberration SA is given to the parallel light beam L11 by the spherical aberration changing mechanism while passing through the condensing optical system O,
Further, a predetermined focus adjustment is performed by a focus position changing mechanism that can be adjusted independently of this spherical aberration changing mechanism. That is, the spherical aberration of the condensed light beam L12 and the focus position in the optical axis direction can be changed arbitrarily and independently. As a result, the fine particles S in the medium B held in the holder H such as a petri dish or a slide glass are stably captured with a strong capturing force by the conical condensing light flux L12 provided with a predetermined spherical aberration SA. Since it is operated and the capturing position is adjusted to the focus position of the observation optical system, it is possible to observe with a good contrast in the observation optical system.

In this embodiment, the lens LP
Although a single lens having a positive refractive power is shown as 1 and LP2, the present invention is not limited to this, and the configuration of the device can be changed within a range that can be easily implemented by those skilled in the art. For example, the lenses LP1 and LP2 may be a lens group instead of a single lens. Also, the lens LP1
May be a negative lens and the lens LP2 may be a positive lens, or vice versa. In that case, the condensing point P'becomes a virtual image.

Furthermore, in this embodiment, a parallel plate and a turret are used as a mechanism for giving an arbitrary spherical aberration to a light beam, but this may be a diffractive optical element instead of a parallel plate, for example. Alternatively, the lens LP1 or LP2 may be composed of a plurality of lens groups, and the same function may be provided by changing the air space of a part thereof.

Further, in the present embodiment, the condensed light flux L1
The spherical aberration changing mechanism for changing the spherical aberration of No. 2 and the focus position changing mechanism for changing the focus position of the condensed light flux L12 have been described as one optical system (second optical system O2). ), It may be arranged between the light source LS1 for optical tweezers and the dichroic mirror DM. For example, another condensing point P ″ is provided in addition to the condensing point P ′, while spherical aberration is corrected. Alternatively, the spherical aberration changing mechanism may be provided on one side, and the focus position may be corrected on the other side (the other focus position changing mechanism is provided).

From the observation light source LS2, the image plane IMG
Although the observing optical system up to (1) shares the optical system O2 including the microscope objective lens forming a part of the condensing optical system O that gives the positive spherical aberration SA, the spherical aberration SA is directly
Since the parallel plate PT1 as a spherical aberration generating means for giving (generating) is not shared, it is not necessary to correct the spherical aberration in this observation optical system.

In the observation optical system shown in the present embodiment, in order to obtain a clear observation image with high contrast, for example, the dark field illumination method or the oblique illumination method which is a conventional technique in the microscope observation method is used. The sample may be illuminated with light.
Further, it is also possible to increase the contrast of the observed image by using a phase difference observation method or a differential interference observation method, which are also conventional techniques, in the observation optical system. Furthermore, confocal microscopes and near-field microscopes (NS) that have become widely used in recent years
It is also possible to configure the observation optical system by using a method such as OM).

Further, in the present embodiment, a wavelength-selective dichroic mirror DM is used as a means for dividing the optical paths of the focusing optical system for optical tweezers and the observation optical system. Other means may be used within the scope of the gist. For example, a polarizing plate may be used to make the light fluxes of the converging optical system for optical tweezers and the observation optical system different from each other, and a polarization beam splitter may be used in place of the dichroic mirror DM for polarization splitting.

In the present embodiment, a lens, a parallel plate, a dichroic mirror, a diffractive optical element or the like is mainly used as a means for guiding the light beam for optical tweezers and the illumination light beam for observation to the fine particles S. Although explained, in practice, it is not necessarily limited to these.

Further, in the present embodiment, the observation optical system is shown as observing an enlarged image of the fine particles S formed on the image plane IMG from above, but instead of such a method,
For example, a method of observing from below such as an inverted microscope may be adopted.

Further, in the present embodiment, the light beam for optical tweezers is applied to the fine particles S in the medium B held by the holder H from above, but the fine particles S of the light beam for optical tweezers are present. The direction of incidence on the medium B may be either up or down. This also applies to the observation optical system. The incident directions of the light flux for the optical tweezers and the illumination light flux for observation and the combination thereof can be freely arranged three-dimensionally within the range according to the gist of the present invention.

Further, in this embodiment, the condensed light flux L
As the spherical aberration mechanism for changing the spherical aberration of No. 12, the turret T in which a plurality of parallel flat plates PT1, PT2, PT3 can be arbitrarily replaced is shown, but this may be replaced with the liquid cell shown in the first embodiment. it can.

Further, the above-mentioned condensing optical system constructed by providing a liquid cell in the optical path of the condensed light flux is not limited to the above-mentioned fine particle manipulating device, and continuously and arbitrarily generates spherical aberration in the condensed light flux. It can also be used for other optical devices that require it.

[0050]

As described above, according to the condensing optical system of the present invention, it is possible to arbitrarily change the length in the optical path direction in the optical path of the generated conical condensed light flux. Since the liquid cell is provided, it is possible to continuously and arbitrarily generate spherical aberration in the condensed light flux passing through the liquid cell by changing the length of the liquid cell in the optical path direction.

Further, according to the fine particle manipulating device of the present invention, appropriate spherical aberration is imparted to the condensed light flux in accordance with the depth of the fine particles to be trapped in the medium, and the lowering of the trapping force can be prevented with sufficient force. It becomes possible to capture and manipulate the sample.

Further, according to the fine particle manipulating device of another aspect of the present invention, the spherical aberration of the condensed light beam and the focus position in the optical axis direction can be arbitrarily and independently changed. Fine particles in the medium held in a holder such as a glass or a slide glass can be stably captured and manipulated with a strong capturing force by a conical focused light flux with given spherical aberration, and the capture Since the position can be adjusted to the focus position of the observation optical system, the fine particles in the medium can be observed with a good contrast in the observation optical system.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a condensing optical system of the present invention and a fine particle manipulation device of the present invention including the condensing optical system.

FIG. 2 is a diagram showing a specific configuration of a liquid cell, (a)
Is a type in which part of the liquid cell is a bellows, (b)
Is a type in which two cylindrical containers are combined so as to partially overlap each other.

FIG. 3 is a principle conceptual diagram of a particle manipulating apparatus according to another embodiment of the present invention.

FIG. 4 is a schematic diagram showing a configuration of a conventional optical tweezers.

FIG. 5 is a partially enlarged view of FIG. 4 and is a view for explaining the operation of fine particles by optical tweezers.

[Explanation of symbols]

Light source for LS1 optical tweezers LS2 Observation light source O Condensing optical system O1 first optical system O2 second optical system DM dichroic mirror P Focus point B medium H holder S fine particles LP1, LP2 lens LC liquid cell LQ liquid IMG image plane

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // C12M 1/00 C12M 1/00 A

Claims (8)

[Claims] 1. A condensing optical system for generating a conical condensed light beam, wherein a liquid cell capable of arbitrarily changing a length in the optical path direction is provided in an optical path of the condensed light beam, A condensing optical system characterized in that continuous and arbitrary spherical aberration is generated in the condensed light flux passing through the liquid cell by changing the length of the cell in the optical path direction. 2. A particle manipulating apparatus having a condensing optical system for generating a conical condensing light beam, and irradiating the condensing light beam to particles in a medium to capture and manipulate the particles. 1. The condensing optical system according to 1 is provided to continuously generate an arbitrary spherical aberration in the condensed light flux to capture the fine particles.
A fine particle operation device characterized by being operated. 3. An observation optical system for observing the fine particles includes a part of the condensing optical system, and the observation optical system is provided with a correction mechanism for correcting a focus position of the condensed light flux. The particle manipulation device according to claim 2, which is characterized in that. 4. A particle manipulating apparatus which has a condensing optical system for generating a conical condensing light beam, and irradiates the condensing light beam to fine particles in a medium to capture and manipulate the fine particles. A fine particle manipulation device characterized in that a spherical aberration of a light beam and a focus position in an optical axis direction can be arbitrarily and independently changed. 5. The converging optical system has a conjugate converging point optically conjugate with a converging point of the converging light beam, and spherical aberration of the converging light beam is changed in the vicinity of the conjugate converging point. 5. The fine particle manipulation device according to claim 4, further comprising a spherical aberration changing mechanism for changing the focus position and a focus position changing mechanism for changing the focus position of the condensed light flux. 6. The focus position changing mechanism is composed of a lens or a lens group having a positive refracting power, which is installed to face the optical path of the condensed light flux so as to face each other. 6. The particle manipulation device according to claim 4, wherein the focus position of the light flux is changed. 7. The focus position changing mechanism includes a lens or a lens group having a positive refractive power and a lens or a lens group having a negative refractive power, which are installed to face each other in the optical path of the condensed light flux. 6. The fine particle operating device according to claim 4, wherein the focus position of the condensed light flux is changed by changing the distance between these lenses or lens groups. 8. The spherical aberration changing mechanism has a liquid cell capable of arbitrarily changing a length in the optical path direction in an optical path of the condensed light flux, and a length of the liquid cell in the optical path direction. 8. The fine particle manipulation according to claim 4, wherein the spherical flux is continuously and arbitrarily generated in the condensed light flux passing through the liquid cell by changing the value of. apparatus.