JP2004303827A - Method of forming point light source for compensation optic - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a reference point light source which is required when a compensation optical device is applied to various imaging devices to be formed independently of the properties of a work as an object of measurement. <P>SOLUTION: Particulates of metal or dielectric material are trapped near the work O as an object of measurement with an optical tweezers device 20 in a non-contact manner, a keenly sharpened light beam is made to impinge on the trapped particulates to form a point light source 19, and reflected light radiated in spherical waves from the point light source 19 is used as reference light for driving the compensation optical device 13. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for artificially creating a reference point light source required when adaptive optics technology is applied to various video devices.
[0002]
[Prior art]
An adaptive optics device that detects and corrects a wavefront distortion of light in real time has been mainly used in the field of astronomy for the purpose of improving a astronomical image blurred due to atmospheric turbulence.
[0003]
This prior art is shown in FIG. The wavefront 21 of the reference light disturbed by the fluctuation of the medium in the optical path is reflected by the deformable mirror 22, a part of the wavefront is taken out by the beam splitter (BS) 25, and it is made incident on the wavefront sensor 26. Here, the deformable mirror is a device in which a plurality of actuators 24 are attached to the back of a thin mirror 23, and the shape of the mirror can be arbitrarily changed by controlling each of the actuators.
[0004]
The wavefront distortion is measured by the wavefront sensor 26, and the measurement result is input to the control device 27. The control device 27 calculates the shape of the mirror required for correcting the wavefront based on the measurement result, and changes the shape of the shape-variable mirror 22 by controlling the individual actuators 24 based on the calculated shape. By performing this series of operations quickly, the distortion of the wavefront of the incident light can be corrected in real time by reflection on the deformable mirror 22. (Refer to, for example, Patent Document 1, Patent Document 2, and Patent Document 3 regarding the adaptive optical device).
[0005]
When this adaptive optics device is incorporated into an astronomical telescope, bright stars existing near the celestial body to be observed are used as reference light. Light from a stellar propagates as a plane wave until it enters the Earth's atmosphere, but its wavefront is distorted by the influence of the atmosphere before it enters the telescope. Using this distorted reference light, the deformable mirror is controlled so as to cancel the effects of atmospheric fluctuations in the optical path as described above, and the object to be observed is observed through the controlled deformable mirror. As a result, it is possible to observe a clear astronomical image excluding the influence of atmospheric turbulence.
[0006]
When there is no bright star near the object to be observed, a high-power laser beam oscillating at a wavelength of 589 nm is emitted toward the sky, and the sodium atomic layer near the altitude of 90 km emits light by resonance scattering. (Artificial star), which can also be used as reference light. (For the artificial star, see, for example, Patent Document 4.)
[0007]
Further, when incorporating the adaptive optics device into a fundus camera, a bright spot on the retina created by irradiating a laser beam to the eye and sharply squeezing the retina as reference light is used. Since the reflected light in the form of a spherical wave is obtained from the bright spot on the retina, when there is no distortion in the cornea or the crystalline lens, the spherical wave from the bright spot on the retina becomes a plane wave due to the lens action of the cornea or the crystalline lens from the eye. Is emitted. However, in general, since the cornea and the crystalline lens of a human eye are distorted, the wavefront of light emitted from the eye from a bright spot on the retina is distorted.
[0008]
Based on this reference light, the deformable mirror is controlled so as to cancel the influence of the distortion of the cornea and the lens present in the optical path, and the cornea and the cornea are observed by observing the retina to be observed through the controlled deformable mirror. A high-resolution retinal image excluding the effects of lens distortion can be observed. (For example, see Patent Document 5).
[0009]
On the other hand, it is composed of a laser light source and a galvanometer mirror for scanning a laser beam, etc., and uses a radiation pressure of laser light to capture and move metal, dielectric fine particles, molecules, cells, etc. in a non-contact manner (for example, , Patent Literature 6, Patent Literature 7, and Patent Literature 8) are known, and such a device is referred to as an optical tweezer device in this specification.
[0010]
[Patent Document 1]
JP-A-5-323213 [Patent Document 2]
JP-A-6-250108 [Patent Document 3]
Japanese Patent No. 3070892 [Patent Document 4]
JP 2002-335218 A [Patent Document 5]
JP 2001-507258 A [Patent Document 6]
JP-A-5-107498 [Patent Document 7]
JP-A-5-93871 [Patent Document 8]
Japanese Patent No. 2947971
[Problems to be solved by the invention]
When the adaptive optics device is applied to various imaging devices, particularly to medical endoscopes such as ventriculoscopes and cystoscopes and microscopes for biological observation, the laser beam is narrowed down in the same manner as when applied to a fundus camera. A method of irradiating an object to be measured with a light source and using a luminescent spot formed thereon as reference light is also conceivable. However, the object to be measured in medical endoscopes and biological microscopes generally has an irregular surface shape and a low reflectance, so it is difficult to create a bright spot on the surface and use it as a reference light. It is.
[0012]
The present invention provides a technique for creating a reference point light source required when applying the adaptive optics apparatus to various video apparatuses without depending on the properties of the measured object.
[0013]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION In order to solve the above-described problems, the present invention is directed to an object caused by fluctuation of a medium existing between an object to be measured photographed by an imaging device and the imaging device, and aberration of an objective lens installed in the imaging device. A method for creating an adaptive optics reference point light source for driving an adaptive optics device for correcting image distortion, wherein metal or dielectric fine particles are brought into contact with an object to be measured in a non-contact manner using an optical tweezer device. A point light source is created by capturing light, sharply focused light is incident on the captured fine particles, and reflected light emitted in a spherical wave shape from the point light source is used as reference light for driving the adaptive optics device. A method of producing a reference point light source for adaptive optics is provided.
[0014]
SUMMARY OF THE INVENTION In order to solve the above-described problems, the present invention is directed to an object caused by fluctuation of a medium existing between an object to be measured photographed by an imaging device and the imaging device, and aberration of an objective lens installed in the imaging device. A method of creating an adaptive optics reference point light source for driving an adaptive optics device for correcting image distortion, wherein a fluorescent molecule is captured near an object to be measured in a non-contact manner using an optical tweezer device. A method for producing a reference point light source for adaptive optics is provided, wherein a light source is produced and fluorescent light emitted in a spherical wave form from the point light source is used as reference light for driving the adaptive optics device.
[0015]
SUMMARY OF THE INVENTION In order to solve the above-described problems, the present invention is directed to an object caused by fluctuation of a medium existing between an object to be measured photographed by an imaging device and the imaging device, and aberration of an objective lens installed in the imaging device. A method of creating a reference light source for adaptive optics for driving an adaptive optics device for correcting image distortion, wherein non-contact capturing of fine particles doped with a dye near an object to be measured is performed using an optical tweezers device. Producing a point light source, and using fluorescence or laser light emitted in a spherical wave form from the point light source as reference light for driving the adaptive optics device. Provide the law.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described based on examples with reference to the drawings. As shown in FIG. 1, the method for creating a reference point light source for adaptive optics according to the present invention is used in a system including an imaging device 12 in which an adaptive optics device 13 is installed and a measurement system 11, and is realized. For this purpose, an optical tweezer device 20 and, if necessary, a light source 19 for a reference point light source are installed.
[0017]
The image device 12 has an operation of forming an image of the measured object O on the CCD camera 17 by the operation of the two lenses of the objective lens L1 and the imaging lens L2. Medical endoscopes or microscopes for observing living tissues and microorganisms. The adaptive optics device 13 generally includes a deformable mirror 16, a beam splitter (BS3), a wavefront sensor 14, and a control device 15.
[0018]
(Example)
An embodiment of the present invention will be described below with an example in which the video device 12 is a medical endoscope. The object to be measured O existing in the measurement system 11 is a brain when the image device 12 is a ventricle, and becomes a bladder wall when the image device 12 is a cystoscope. An optical filter that illuminates the object to be measured O (the optical system for illumination is not shown in the drawing) and blocks the reflected light from the objective lens L1, the beam splitter BS1, and the laser light for the optical tweezers device of the video device 12. F, an image is taken by the CCD camera 17 via the adaptive optics device 13 and the imaging lens L2, and an image of the measured object O is displayed on the monitor 18.
[0019]
At this time, the fluctuation of the medium (the cerebrospinal fluid in the case of a ventriculoscope or the water injected into the bladder in the case of a cystoscope) between the object O to be measured and the objective lens L1, and the aberration of the objective lens L1 Due to the influence of, the acquired image is generally unclear.
[0020]
The compensation optical device 13 installed in the video device 12 for the purpose of correcting the fluctuation of the medium between the object O to be measured and the objective lens L1 and the aberration of the objective lens L1 to obtain a clear object image. Drive. Although the video device 12 in this example is composed of two lenses, the objective lens L1 and the imaging lens L2, a combination lens is used to improve the quality of the image, Other configurations that perform the same operation, such as adding a relay lens system for internal transmission, are also conceivable. On the other hand, as for the adaptive optics device 13 incorporated in the video device 12, a liquid crystal phase modulation element is used instead of the shape-variable mirror 16 (for example, see Japanese Patent Application Laid-Open No. 2002-40368, "Optically Driven Wavefront Correction Video Method and Device"). Reference) and other configurations that perform the same operation are also conceivable.
[0021]
In order to drive the adaptive optics device 13, the wavefront of the light distorted by faithfully reflecting the fluctuation of the medium between the object O to be measured and the objective lens L1 and the aberration of the objective lens L1 is corrected by the adaptive optics. It must be input to the device 13. For this purpose, a method is conceivable in which an ideal point light source is created in the vicinity of the object O to be measured and spherical light emitted from the point light source is used.
[0022]
Note that, in the created point light source, a plane wave is input to the adaptive optics device 13 when there is no fluctuation of the medium between the measured object O and the objective lens L1 and no aberration of the objective lens L1. Must be arranged as follows. The position of the point light source created at this time is inevitably on the focal plane of the objective lens L1 and near the measured object O.
[0023]
In order to create the above point light source, first, metal or dielectric fine particles P are introduced near the object O to be measured. A laser beam from the optical tweezer device 20 is sharply focused and irradiated onto the fine particles P, and the fine particles P are captured near the focal point. Next, while capturing the fine particles P, the focal position of the laser beam is scanned to move the fine particles P to a position where the point light source is to be arranged. The laser light from the light source 19 for the reference point light source is radiated to the metal or dielectric fine particles P captured at a predetermined position by sharply narrowing down the beam with the objective lens L1 via the beam splitter BS2 and the beam splitter BS1. In this case, the size and shape of the fine particles P need to be appropriately selected so that the irradiated sharply focused laser light is emitted as spherical wave-like reflected light.
[0024]
For example, when the size of the fine particles P is smaller than the spot size of the laser to be irradiated, the shape of the fine particles P must be substantially spherical so that reflected light having a substantially spherical wave shape can be obtained based on the theory of Mie scattering. . The fine particles P thus irradiated with the laser light that is sharply focused serve as a reference point light source for driving the adaptive optics device.
[0025]
The wavelength of the laser light used for capturing the fine particles in the optical tweezer device 20 and the wavelength of the laser light used in the light source 19 for the reference point light source must be different enough to be separated by a general optical filter. Must. In FIG. 1, an optical path through a beam splitter BS1 and an objective lens L1 inside the imaging device 12 is used to introduce the laser light for capturing fine particles emitted from the optical tweezers to a position where the fine particles P are captured. However, the same operation can be realized by using other optical elements without using the beam splitter BS1 and the objective lens L1.
[0026]
The spherical wave-like reflected light from the fine particles P passes through the objective lens L1, the beam splitter BS1, and the optical filter F and enters the adaptive optics device 13. The optical filter F is installed to prevent the scattered light generated when the laser light for the optical tweezers captures the fine particles P from entering the adaptive optics device 13.
[0027]
The reflected light in the form of a spherical wave from the fine particles P is ideally converted into a plane wave to the compensating optical device 13 if there is no fluctuation of the medium between the measured object O and the objective lens L1 and no aberration of the objective lens L1. Incident. However, in many cases, a distorted wavefront is incident on the adaptive optics 13 due to the fluctuation of the medium between the measured object O and the objective lens L1 and the influence of the aberration of the objective lens L1. You. The distorted wavefront is reflected by the deformable mirror 16, and a part of the reflected wavefront is input to the wavefront sensor 14 by the beam splitter BS3. The wavefront sensor 14 measures the distortion of the wavefront, and the measurement result is input to the control device 15.
[0028]
The control device 15 changes the shape of the deformable mirror 16 based on the measurement result. For example, if the wavefront has a convex distortion, the deformable mirror is deformed into a concave shape so that the convex wavefront is converted into a flat wavefront during the reflection process. The wavefront of the reflected light from the object to be measured O (light for imaging including information on the object to be measured O) is also distorted for the same reason as that of the reflected light from the fine particles P, and is photographed by the CCD camera 17 due to the effect. The image of the measured object O is unclear. Therefore, when the object to be measured O is observed through a deformable mirror controlled using the reflected light from the fine particles P, the fluctuation of the medium between the fixed object to be measured O and the objective lens L1 and the objective lens L1 The distortion of the wavefront due to the aberration is corrected, and a clear object image can be obtained in principle.
[0029]
In the method described above, metal or dielectric fine particles P are used as a reference point light source for driving the adaptive optics device 13. Next, instead of the fine particles P, one or a plurality of fluorescent molecules P (the same “P” as the “fine particles P” is attached for convenience of explanation of FIGS. 1 and 2 as in the first embodiment). ) Is captured at the above-described position using the optical tweezers device 20.
[0030]
In this case, due to the action of the laser light from the optical tweezers for capturing the fluorescent molecule (group), fluorescence having a different wavelength from the laser light is emitted from the fluorescent molecule. Consider a case where the size of the fluorescent molecule (group) is sufficiently small and the fluorescent light therefrom is emitted in a spherical wave shape. When this is used as a reference point light source for driving the adaptive optics device 13, the adaptive optics device 13 can be operated based on the principle described above, and finally, the measured It is possible to obtain a clear object image excluding the influence of the fluctuation of the medium between the object O and the objective lens L1 and the aberration of the objective lens L1.
[0031]
Next, instead of the fluorescent molecules P, fine particles P to which a dye has been added (the same “P” as “fine particles P” is used for convenience in describing FIGS. 1 and 2 as in Example 1) are described above. Consider capturing at the above-described position using the optical tweezers device 20. In this case, similarly to the case of the fluorescent molecules, the laser light from the optical tweezers for capturing the fine particles P causes the fine particles P to emit fluorescence having a different wavelength from the laser light.
[0032]
Further, depending on conditions, the fine particles behave as a resonator, and laser oscillation occurs. When fluorescence or laser light emitted in the form of a spherical wave from fine particles to which these dyes are added is used as a reference point light source for driving the adaptive optics device 13, based on the principle described above, the adaptive optics device is used. 13 can be operated to finally obtain a clear object image excluding the influence of the fluctuation of the medium between the object to be measured O and the objective lens L1 and the aberration of the objective lens L1. it can.
[0033]
When using the laser oscillated by the fine particles, similarly to the case of using metal or dielectric fine particles, the fine particles are irradiated with the laser light from the light source for the reference point light source, and are irradiated with the excitation light. It is also possible to cause laser oscillation.
[0034]
The embodiments of the method of producing the reference point light source for adaptive optics according to the present invention have been described based on the embodiments, but the present invention is not limited to such embodiments and falls within the scope of the claims. It goes without saying that there are various embodiments.
[0035]
【The invention's effect】
As described above, according to the method for creating a reference point light source for adaptive optics of the present invention, a reference point light source required when applying an adaptive optics device to various video devices is created without depending on the properties of an object to be measured. And the field of application of the adaptive optics device can be expanded.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing an embodiment of the present invention.
FIG. 2 is a conceptual diagram of a conventional adaptive optics system using a deformable mirror.
[Explanation of symbols]
REFERENCE SIGNS LIST 11 measurement system 12 imaging device 13 adaptive optics device 14 wavefront sensor 15 control device 16 variable shape mirror 17 CCD camera 18 monitor 19 light source for reference point light source 20 optical tweezer device 21 reference light wavefront 22 variable shape mirror 23 thin mirror 24 actuator 25 Beam splitter (BS)
Reference Signs List 26 Wavefront sensor 27 Controller P Metal or dielectric fine particles, fluorescent molecules, fine particles to which dye is added O Object to be measured L1 Objective lens L2 Imaging lens F Optical filters BS1, BS2, BS3, BS Beam splitter

Claims (3)

An adaptive optics device for correcting a fluctuation of a medium existing between an object to be measured photographed by an image device and the image device and a distortion of an object image caused by aberration of an objective lens installed in the image device. A method of creating a reference point light source for adaptive optics that drives
Non-contact trapping of metal or dielectric fine particles in the vicinity of the object to be measured using an optical tweezers device, creating a point light source by inputting sharply focused light to the captured fine particles, from the point light source A method for producing a reference point light source for adaptive optics, wherein reflected light emitted in the form of a spherical wave is used as reference light for driving the adaptive optics device. An adaptive optics device for correcting a fluctuation of a medium existing between an object to be measured photographed by an image device and the image device and a distortion of an object image caused by aberration of an objective lens installed in the image device. A method of creating a reference point light source for adaptive optics that drives
A fluorescent light molecule is captured in the vicinity of the object to be measured in a non-contact manner using an optical tweezer device to form a point light source, and the fluorescent light emitted in a spherical wave form from the point light source is a reference for driving the adaptive optics device. A method for producing a reference point light source for adaptive optics, wherein the light source is used as light. An adaptive optics device for correcting a fluctuation of a medium existing between an object to be measured photographed by an image device and the image device and a distortion of an object image caused by aberration of an objective lens installed in the image device. A method of creating a reference point light source for adaptive optics that drives
A point light source is created by non-contactly capturing fine particles to which a dye is added in the vicinity of the object to be measured using an optical tweezers device, and the fluorescent light or laser light emitted from the point light source in the form of spherical waves is used as the compensation optical device. A method for producing a reference point light source for adaptive optics, wherein the reference light source is used as a reference light for driving a reference light.

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