Modular objective assembly

A modular laser objective for use with a microscope is provided. A mounting modular body permits the modular objective to be releasably mounted to the turret of a microscope. The objective has an optical axis that permits an image beam to be emitted through the objective toward the eyepiece of a microscope. The modular body supports a mirror positioned at an angle to the optical axis of the objective. A modular laser assembly is mounted on the modular body on a first side of the mirror for directing a laser beam toward the mirror so that the energy is reflected off the mirror and through the objective in a direction that is substantially aligned with the optical axis of the objective. A modular indicator assembly is received in the modular body and includes a source of light positioned with the light incident on the other side of the mirror to reflect a beam of light in a direction opposite to the direction of the laser beam to provide an optical representation at the eyepiece of a microscope or on a camera of the position on the target of the laser beam being emitted by the objective.

FIELD OF THE INVENTION

The present invention relates generally to a modular objective assembly for use with a microscope and, in particular to a modular objective assembly to be releasably mounted to the turret of a microscope that includes a modular laser sub-assembly and modular indicator sub-assembly that permits the user of a microscope to see an indicator in the eyepiece of a microscope of the position where laser energy is directed at a specimen positioned at the objective of a microscope.

BACKGROUND

Recent advances in biology and medicine have led to the development of laser beam microsurgery on cells. The laser beam is well adapted to micromanipulation of small objects, such as single cells or organelles. It provides the advantage of non-contact ablation, volatilization, sterilization and denaturing, cutting, and other forms of thermal and actinic-light treatment. The four parameters of focal spot size, laser wavelength, pulse duration, and laser power, provide a variety of regimes suitable for different applications.

One example of a use of laser beam microsurgery is the application of laser beams to the treatment of a mammalian oocyte and embryo. However, laser beam microsurgery in a number of inverted or upright microscopes can be utilized for many different surgical or medical applications.

In accordance with commonly practiced methods of laser beam microsurgery, the person conducting the microsurgery watches a screen displaying the sample and an indication of where the laser beam would be applied on the sample. Sometimes, a plurality of isothermal contour rings can be provided to demonstrate the range of thermal effects of the laser beam. Examples of such heat rings are provided in U.S. Pat. No. 7,359,116 and U.S. patent application Ser. No. 11/764,064.

Combining an objective, a laser and a directional beam to provide a visible indication of the targeting of the invisible laser beam has been proposed in U.S. patent application Ser. No. 12/481,363, filed on Jun. 9, 2009, now U.S. Pat. No. 8,149,504. However, the structure of these laser objectives lead to interference problems with the turret geometry of certain microscopes. Accordingly, a self-contained modular objective that eliminates such interference issue would be desirable.

SUMMARY OF THE INVENTION

This invention relates, in general, to a modular assembly having an objective, a laser assembly and an indicator assembly and the use thereof. The invention preferably improves upon systems and methods by providing a modular laser assembly configured and connected to an objective to preferably provide a laser beam coinciding with the optical axis of the objective, as well as providing a visible indication of the position of the laser via the eyepiece of the microscope.

According to an embodiment of the invention, the modular objective assembly can provide a mounting modular body that is mountable on a turret of a microscope. The modular body includes an objective assembly having an optical axis that permits an image beam to be emitted through the objective toward the eyepiece of a microscope and through a mirror positioned at an angle to the optical axis of the objective. A modular laser assembly is positioned on the modular body on a first side of the mirror for directing laser energy toward said mirror so that the laser energy is reflected off of the mirror and through the objective in a direction that is substantially aligned with the optical axis. A modular indicator assembly is also mounted on the modular body and provides an indicator beam being emitted toward the other side of the mirror, for directing the light beam in a direction that is opposite to the direction of the laser energy to permit an optical representation at the eyepiece of the microscope, thus being visible therethrough. The person conducting the microsurgery can thus view the sample and the position of the laser relative to the sample through the eyepiece while conducting the microsurgery.

Other objects and features of the present invention will become apparent from the following detailed description, considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for the purpose of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.

DETAILED DESCRIPTION

An illustrative embodiment of the present invention relates to a modular system for providing a laser beam coinciding with the optical axis of the objective suitable for use with a microscope, and an indicator beam that is visible through the eyepiece of a microscope, the visible beam preferably indicating the position of a laser beam. The invention also relates to a modular objective assembly having an objective, an indicator assembly and a laser assembly; a microscope having an objective assembly; as well as to an indicator assembly that can be used with a microscope or other device with which laser manipulation is conducted. The invention is also directed toward providing a modular objective that will assist in conducting laser microscopy using an indicator beam indicating the position of the laser through the eyepiece of the microscope.

Reference is first made toFIGS. 1A and 1Band several other figures to understand the functionality of the modular objective of the instant invention and the functional components thereof.FIG. 1Ais a schematic view of the modular objective assembly100of the instant invention and is shown as having a housing110having an objective120, a turret mount130, a modular indicator assembly300and a modular laser assembly500. As is depicted inFIG. 1Bobjective assembly100is preferably mountable onto a turret50of a conventional microscope via turret mount130. For example, as is depicted inFIG. 7, a modular body, generally indicated as200, includes a turret mount130, which can include a threaded portion corresponding to a threaded portion of the turret of the microscope such that objective assembly100can be screwed onto the turret. Alternatively, turret mount130can be slid or snapped into place, or include an external locking mechanism to mount modular objective assembly100onto the turret and preferably maintain objective assembly100in place on the turret of the microscope.

Referring again toFIG. 1A, objective120preferably has an optical axis122, and the imaging beam travels close to parallel to this axis. Preferably, the microscope emits an image beam through the stage, objective120, and is directed into the eyepiece of a microscope such that the sample on the stage can be seen via the eyepiece.

The image beam preferably focuses via the tube lens and eyepiece (not shown), at the eye of the viewer and can be adjusted to adapt to the viewer. The image beam is preferably close to coaxial with optical axis122when objective assembly100is mounted onto the turret of the microscope. Accordingly, the sample on the stage of the microscope, for example, where the sample is being studied, manipulated, etc. along the optical path122of objective120can be seen through the eyepiece of the microscope.

In accordance with the embodiment shown, objective assembly100also includes a modular laser assembly500that functions in the manner shown and described in U.S. Pat. No. 7,359,116 and U.S. patent application Ser. No. 11/764,064, both of which have been assigned to the same assignee Hamilton Thorne, Inc. and are incorporated in their entirety by reference herein.

Referring toFIG. 1A, laser assembly500preferably includes a laser source510such as a laser diode, a collimating lens520and a mirror530. Laser source510preferably emits an elliptical cone of laser light, toward collimating lens520, more preferably diverging from laser source510toward collimating lens520. It is to be understood that the laser light emitted by laser source510toward collimating lens520can converge or be collimated without deviating from the scope of the invention. The laser light is preferably transmitted toward and through collimating lens520, after which time the laser light is collimated. Therefore, the laser light can exit collimating lens520as a collimated (or close to collimated) laser beam522. The laser beam522can have a wavelength in the range of 300 nm to 1500 nm, power in the range of 10 mW to 1000 mW and a pulse duration in the range of 1 microsecond to 1 second. This wavelength range should not be interpreted to constrain the wavelengths of the laser to be used in accordance with the instant invention, since any wavelength produced by a small laser source should be usable with the instant invention.

Collimated laser beam522can be emitted toward mirror530. In accordance with an exemplary embodiment of mirror530, a coating532such as an infrared reflector can be provided on mirror530facing laser source510. Preferably, coating532enhances the reflectivity of an infrared collimated laser beam522off mirror530toward mirror124. It is reflected off mirror124toward objective assembly120.

FIG. 1Aillustrates the path of collimated laser beam522from collimating lens520to and through objective120. Preferably, collimated laser beam522exits collimating lens520and travels along a first laser path524toward mirror530. Once collimated laser beam522contacts mirror530, collimated laser beam522reflects off mirror530and travels along a second laser path534toward the surface124aof dichroic mirror124. A dichroic mirror124is preferably located within objective120such that the laser beam522traveling along the second laser path534contacts the objective mirror surface124aand is reflected off the objective mirror124into a third laser path535. The dichroic mirror is coated with a layer suitable for enhancing IR reflection at the incident angle, which is generally 45°. The third laser path535is preferably coaxial with and substantially coincides with the optical axis122of objective120, thus traveling within objective120and further toward the stage of the microscope. Accordingly, collimated laser beam522is also coaxial and antiparallel with the image beam of the microscope traveling in the opposite direction, toward the object and thus away from eyepiece. Since the laser beam may be in the infrared wavelength region as well as traveling away from the eyepiece, it is likely to be invisible. Therefore, the collimated laser beam522is unlikely to be visible via the eyepiece of the microscope. The position of the collimated laser beam522and preferably the heat isothermal contour rings associated with it can be displayed on a screen, which a person may watch while conducting the microscopy.

As shown inFIG. 1A, a modular indicator assembly300can be provided, preferably on the opposite side of objective mirror124from laser assembly500. As shown, indicator assembly can include an indicator light source310such as an LED (light emitting diode), which emits light toward mirror an indicator mirror330. Preferably, the light is emitted from the indicator source310toward a reducing element340, thereafter toward collimating lens320which collimates the light such that a collimated beam of light, referred to herein as indicator collimated beam322, exits indicator collimating lens320toward indicator mirror330. Preferably the wavelength is close to 650 nm, although for some users colorblindness indicates that a shorter wavelength is preferable.

Indicator collimated beam322can then reflect off indicator mirror330along light path334toward the opposite surface of two-sided objective mirror124such that the indicator beam322is reflected toward the eyepiece of the microscope. Preferably, indicator light source310and indicator collimating lens320are mounted on an indicator mount360which is preferably connected to housing110.

Referring toFIG. 1A, indicator collimated beam322preferably travels toward indicator mirror330along a first indicator path324from indicator collimating lens320. After reflecting off indicator mirror330, indicator beam322travels along a second indicator path334until it reflects off objective mirror124into a third indicator path335. Preferably, third indicator path335is coaxial with but is the opposite direction to third laser path535and thus optical path or optic axis122of objective120. More preferably, third indicator path335is coaxial to and substantially coincides with the image beam of the microscope and travels toward the eyepiece of the microscope. Reflection off the surfaces of the dichroic mirror124may be enhanced by coatings designed to preferentially simultaneously reflect the light emitted by indicator source310, as well as the light from the laser assembly mirror532.

Preferably, the diameter of light emitted toward indicator collimating lens320is controlled, for example, reduced from the diameter of indicator light source310. For example, a reducing element340can be provided between indicator light source310and indicator collimating lens320to reduce the diameter of the indicator light being emitted toward indicator collimating lens320. An embodiment of reducing element340can have a generally round shape, such as a substantially round and flat disk, with a central aperture. Alternatively, the reducing element can be elongated, cylindrical, or rectangular, hexagonal, etc. without deviating from the scope of the invention. An example of the reducing element, as well as an exemplary embodiment of the indicator assembly is described in further detail in U.S. patent application No. 12/481,363 entitled OPTICAL INDICATOR FOR MICROSCOPE LASER BEAM MANIPULATION the contents of which are incorporated by reference as if fully set forth herein.

The reducing element preferably includes an aperture through which indicator light can be emitted toward indicator collimating lens320. Preferably, the reducing element prevents the indicator light from passing through the remaining portion of reducing element. Therefore, the diameter of the effective light source emitted toward indicator collimating lens320can be controlled by controlling the size of aperture. In accordance with an exemplary embodiment, aperture has a diameter of between about 5 to 10 μm, more preferably approximately 5 μm. Whereas the aperture may have a generally round shape, it is to be understood that the shape of aperture can be varied without deviating from the scope of the invention.

As shown, laser beam534preferably reflects off a first side124aof objective mirror124and indicator beam322preferably reflects off a second side124bon the opposite side of objective mirror124. Side124ais generally coated with a layer to enhance the reflectivity in the laser wavelength. Second side124bcan include a reflector coating or other reflection enhancing mechanism. Alternatively, second side124bcan be left uncoated or coated with an anti-reflector coating, in which case side124ais used to reflect in opposite directions both the laser beam and the indicator beam. The coating on side124acan be designed to preferentially reflect both the laser wavelength and the illuminator source wavelength. The use of a two-sided mirror of the type contemplated herein in a laser objective is illustrated and described in U.S. patent application Ser. No. 12/481,363, filed on Jun. 9, 2009, which is assigned to Hamilton Thorne, Inc. the assignee herein which is incorporated by reference as if fully set forth herein.

Whereas the embodiments shown herein illustrate a single objective mirror124, a plurality of mirrors can be provided as a matter of application specific design choice. In accordance with an embodiment wherein more than one mirror is provided, the laser assembly and the indicator assembly can be on the same side of the optical path, be positioned perpendicularly, etc. without deviating from the scope of the invention. Additionally, whereas a 45° mirror may be preferred, it is to be understood that the angle of mirrors124,330,530can be varied, as well as the position of the mirror along the optical path of the objective without deviating from the scope of the invention.

Referring next toFIGS. 2 through 7, the modular indicator assembly300and the laser assembly500are preferably positioned in tubular housings400,600, respectively. The tubular housings can comprise a variety of shapes, and have, for example, a circular or rectangular cross section.

As depicted inFIGS. 2-7, the modular assembly100including a modular body200that includes a turret mount130that is arranged and positioned on the turret of a microscope such that the optical beam incident on a lens336inFIG. 1, at the base of the objective converges at an angle of less than or equal to about 0.5° with the optic axis at the objective mirror124. The optical beam emerging from the lens336can preferably be collimated and parallel to the optical axis. Once the distance between the laser510and the laser collimator lens520has been established, such that the laser focus coincides with the visible light focus on the object on the stage, the laser focus can be maintained and adjustments may not be necessary. Preferably, the distance between the laser510and the laser collimator lens520is established and fixed during manufacture, for example, at the factory. Similarly, the position of the laser beam534may be adjusted with regard to dichroic mirror124. For example a movable mirror may be substituted for the fixed laser mirror530, enabling the laser beam to be moved across the field of view. It may be preferable to avoid adjusting the laser collimator distance postproduction of the assembly100. The distance between the indicator aperture340and the indicator collimator lens320can also be established and fixed during manufacture.

Referring next toFIGS. 2-7, the manner in which the components of the modular objective are assembled is depicted. As illustrated inFIG. 1, in an exemplary embodiment the objective includes an outside housing110made of brass, an internal modular body200made of brass, [seeFIG. 7], a laser module500made of aluminum and an indicator module300also made of aluminum. Laser module500and indicator model300are positioned in modular body200, focused and adjusted in the factory, and then laser module500and indicator model300, are inserted into housing110. The completed assembly provides a modular objective to be mounted to the turret of a microscope that will avoid interference problems with the turret geometry of most conventional microscopes.

Reference is made toFIG. 7, wherein modular body200includes a laser module slot210for receiving laser module500. The modular body also includes an indicator module slot220on the opposite side for receiving the indicator module300. Openings can be provided in the modular body to provide X and Y adjustments to the position of the spot produced by the indicator module during assembly. The modular body also includes a turret mount130to permit the objective to be directly mounted to a microscope turret. In the alternative, turret mount130can be received in an adapter to permit the objective to be mounted on the turrets of numerous microscopes without departing from the spirit of the instant invention.

As illustrated inFIGS. 5 and 6, laser module500can be constructed within a rectangular tube600. Collimating lens520is secured to the tube with a holding screw and with appropriate adhesive. The laser510can be preferentially contained within (or without) a TO-can, at a distance from the collimating lens520which can be determined by the required confocality of the laser beam522. The laser position can be adjusted in the lateral XY position and fixed with the screw517. When the desired position is obtained, screws517or other retaining member can hold the laser510in position and centralize it. It can then be potted into place with appropriate adhesive.

The desired laser distance from its collimator lens can be determined during assembly to assure that the laser image is produced on the object at exactly the same distance from the objective as the object when the object is in focus. If the objective is corrected for infinity, since the refractive index of typical lens component materials is slightly lower at λ=1450 nm than in the visible wavelength range, the visible beam can be collimated and the laser beam can converge slightly as it is directed to mirror530then paraxial to the optical axis122on to the objective lens system.

As discussed above, a diverging lens336may be provided below the dichroic mirror. This lens is preferably diverging. The visible beam can converge slightly as it passes down through the dichroic mirror on its way from the objective120to diverging lens336and the tube lens. The IR beam can subtend a lower angle with the optic axis than the visible beam, in order to achieve confocality between the laser focus and the visible focus. Either adjustment can be made when the laser module is assembled at the factory. It is clear that any combination of lens336and objective120can be accommodated by varying the laser-collimator distance to focus the laser on the spot being imaged.

In an exemplary embodiment the laser module500is prefocused to provide a usable objective, since it is preferred that the laser is focused at exactly the visual focal point on the object. Since the refractive index n of the lens components is lower for the □˜1450 nm IR beam than for the visible □˜500 nm light [typically if n is refractive index, the reduction in (n−1) is ˜5%], the objective focal length in the IR will likely be longer than in the visible range. The laser beam522may be more convergent in order to focus at the same point as the visible light, i.e. at the object. Furthermore the optical beam itself may not be exactly collimated at the dichroic mirror124, which may facilitate obtaining a collimated beam out of the diverging final lens336, which may require the beam incident on it to be converging. The visible beam can therefore be slightly converging as it travels from objective to lens336.

In assembling the laser module600, the objective120can be used to produce an image of the object. The laser510itself is moved appropriately in the X and Y transverse directions, and the collimator lens520is moved in the Z direction, until the laser spot is in the correct position and at the correct focus. The laser can then be sealed in position with supporting screws and/or adhesive.

The indicator assembly300is preferably constructed within a similar module400having a rectangular or circular cross-section, preferably positioned on the opposite side of the objective120. The optical elements can include the LED310, the aperture340, and the collimating lens320. The indicator beam can travel initially parallel to the optic axis122. It can be reflected by an indicator mirror330on to the lower surface of the objective dichroic mirror124, and is preferably reflected from that surface of the dichroic mirror to travel parallel to the optic axis through lens336to the microscope tube lens, which preferably focuses the indicator beam322to the image plane, either at the eyepiece or on a camera. When the beam is partially transmitted by surface124b, the transmitted part will be reflected from the other surface124aand travel parallel to the beam reflected from124b. The image of the indicator beam or aperture can appear as a small disk at the image plane.

Setting the indicator beam focus can be similar to setting the laser focal adjustment described above. The indicator assembly300can be placed in the modular body200, with a lens of the same focal length and relative optical position as lens336, so that the microscope tube lens can produce an image on the camera or at the eyepiece plane, and the position of the indicator collimating lens320can be adjusted until a clear image of the aperture or indicator beam is visible. At that point the distance between the collimator320and the indicator beam source's internal aperture can be fixed, for example, by a holding screw and an appropriate adhesive. The indicator assembly300can then be mounted into the housing110onto the objective120.

The thread of the turret mount130of the objective120is preferably standard RMS [0.800 inch-36 55° Whitworth], the parfocal length is standard 45 mm, and the entire objective120can be contained within a shell of outer diameter 31 mm. Other thread types suitable for use in the instant invention include M25@45 mm parfocal length, M45@60 mm parfocal length and M27@45 mm parfocal length.

Embodiments of the invention preferably include the method of mounting a laser assembly500(which may be IR (invisible)) and an indicator assembly300, within the same housing110with an objective120. Such an assembly100can preferably produce precise laser irradiation wherever required on the object on the stage of a microscope, as well as a visible position indicator which can be seen on the monitor screen or through the eyepiece.

The examples provided are merely exemplary, as a matter of application specific to design choice, and should not be construed to limit the scope of the invention in any way.