JP2003005080A - Differential interference microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a differential interference microscope which permits easy changing of observation conditions without requiring intricate operations, such as mechanical actions. SOLUTION: This differential interference microscope has illumination means 2 which forms to luminous fluxes varying in polarization directions, an enlarging optical system 3 which forms an image by superposing the two luminous fluxes transmitted through an observation object 1, a space optical modulator 4 which regulates phase differences between the two luminous fluxes, imaging means 5 which picks up the image of the observation object 1, image analyzing means 6 which analyzes this image and parameter determining means 7 which determines the parameter necessary for modulation of the space optical modulator 4 in accordance with the results of the analysis. The illumination means 2 has a light source 21, a Nomarski prism 23 and a condenser lens 24. The enlarging optical system 3 has an objective lens 31, a Nomarski prism 34 and an analyzer 33. The analyzer 33 and the polarizer 22 are arranged in a relation of crossed Nicols.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential interference microscope for observing the phase distribution of microcellular objects such as cells and bacteria, or the binding structure of metals.

[0002]

2. Description of the Related Art In a differential interference microscope, an illuminating light is separated into ordinary light and extraordinary light by a birefringent prism, which is applied to an object to be observed, and the transmitted light or reflected light is interfered with the object to be observed. The gradient of the phase distribution of is observed as an image.

In order to satisfactorily observe various observation objects, this differential interference microscope employs a method in which a birefringent prism is subtly moved to change the phase difference between an ordinary ray and an extraordinary ray and the observation is performed. ing. Regarding the fine movement of the prism, a method using a motor or the like has recently been proposed in, for example, Japanese Patent Laid-Open No. 9-105864. The differential interference microscope disclosed in JP-A-9-105864 will be schematically described with reference to FIG.

In the system of FIG. 11, the polarizer 101 and the analyzer 106 are arranged so that the polarization directions are crossed Nicols. Further, the localization surface of the Nomarski prism 102 is arranged so as to coincide with the front focal plane of the condenser lens 103. As used herein, the term front side refers to the side on which light enters the lens system,
Further, the term "rear side" refers to the side where light is emitted from the lens system.

In FIG. 11, the light flux emitted from the light source 100 is converted into light whose polarization direction is 45 degrees with respect to the paper surface by using the polarizer 101, and the Nomarski prism 1
It is incident on 02. The Nomarski prism 102 is arranged such that the direction of its shear is parallel to the paper surface, and the incident light beam is divided into an ordinary ray having a polarization direction perpendicular to the paper surface and an extraordinary ray parallel to the paper surface. It is separated into the light flux of the book. The two separated beams are the condenser lens 1
After passing 03, it passes through two different points of the observation object 1 at a specific distance Δ.

Two light beams having different polarization directions which have passed through two different points of the observation object 1 pass through the objective lens 104,
The Nomarski prism 105 combines them into one light beam. The combined light fluxes interfere with each other by passing through the analyzer 106, and the interference image is picked up by the image pickup means such as the CCD 107 as the read information of the observation object 1.

In this device, the Nomarski prism 10
2 and the Nomarski prism 105 are moved using a stepping mode or the like to change the relative phase difference between the two light beams reading the observation object 1 to obtain a plurality of images. Furthermore, the observed object 1 is based on the plurality of images.
The computer 108 restores the phase distribution of the.

[0008]

In the conventional general differential interference microscope, the observer manually moves the Nomarski prism mechanically in order to change the observation conditions for various observation objects. Therefore, it is necessary to change the phase difference between the ordinary ray and the extraordinary ray. In addition, JP-A-9-1
As seen in No. 05864 and the like, there is an example in which a stepping motor or the like is used for moving the Nomarski prism, but in many cases the precision is not sufficient because of mechanical operation or the adjustment is complicated. As described above, it is difficult for the known differential interference microscopes to easily change the observation conditions. In addition, this makes it difficult to observe various objects under optimum observation conditions.

The present invention has been made in view of the above-mentioned problems, and its main purpose is to easily change the observation condition without requiring complicated operations such as mechanical operation. It is to provide a differential interference microscope. A secondary object of the present invention is to provide a differential interference microscope capable of observing various observation objects under optimum observation conditions.

[0010]

A differential interference microscope of the present invention comprises an illuminating means for generating a plurality of light beams with different polarization directions, which are irradiated onto the observation object, and a polarization direction from the illumination means via the observation object. The relative phase difference between a plurality of light fluxes having different polarization directions generated by the illuminating means and an optical system for forming an image of the observation object on the image plane by superimposing a plurality of different light fluxes on each other, And an adjustable spatial light modulator. The spatial light modulator adjusts the phase difference between a plurality of light beams from the illuminating means having different polarization directions, so that the observation condition can be easily changed without requiring mechanical operation.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 shows the configuration of a differential interference microscope according to the first embodiment of the present invention. As shown in FIG. 1, the differential interference microscope of the present embodiment includes an illuminating unit 2 that generates two light beams with different polarization directions with which the observing object 1 is irradiated, and an illuminating unit 2 that passes through the observing object 1. Between a magnifying optical system 3 that superimposes two luminous fluxes having different polarization directions to form an image of an observation object on the imaging plane, and two luminous fluxes that are generated by the illumination means 2 and have different polarization directions. Of the relative optical phase difference of which is adjustable by a signal from the outside, an image pickup means 5 for picking up an image of the observation object 1 generated on the image plane, and an image picked up by the image pickup means Image analysis means 6 for analyzing features
And a parameter determining means 7 for determining a parameter required for modulation of the spatial light modulator 4 based on the analysis result of the image analyzing means 6.

The illumination means 2 comprises a light source 21 and a polarizer 22.
, Nomarski prism 23, and condenser lens 2
4 and. The condenser lens 24 and the Nomarski prism 23 are arranged such that the front focal plane of the condenser lens 24 and the localization position of the Nomarski prism 23 coincide with each other. The magnifying optical system 3 has an objective lens 31, a Nomarski prism 34, and an analyzer 33. Objective lens 31 and Nomarski prism 3
Reference numeral 4 is arranged so that the pupil position of the objective lens 31 and the localized position of the Nomarski prism 34 coincide with each other. The shear directions of the respective Nomarski prisms 23 and 34 are both parallel to the paper surface of FIG. The polarization direction of the polarizer 22 is 45 degrees with respect to the paper surface of FIG. 1, and the analyzer 33 is arranged in a crossed Nicol relationship with the polarizer 22.

In the illuminating means 2, the light flux emitted from the light source 21 is incident on the polarizer 22, and its polarization direction is shown in FIG.
A luminous flux of 45 degrees with respect to the paper surface of the sheet passes through this. The light flux that has passed through the polarizer 22 passes through the Nomarski prism 23, so that the ordinary rays 11 whose polarization directions are orthogonal to each other
And the extraordinary ray 12 are separated into two light beams and enter the condenser lens 24. Here, the polarization direction of the ordinary ray 11 is perpendicular to the paper surface of FIG. 1, and the polarization direction of the extraordinary ray 12 is parallel to the paper surface of FIG. These two light beams with different polarization directions enter the spatial light modulator 4.

The spatial light modulator 4 can modulate the phase difference between incident light of a specific polarization direction and incident light of other polarization directions by an external signal such as electricity. The spatial light modulator 4 is arranged so as to change the phase difference between the ordinary ray 11 having a polarization direction perpendicular to the plane of FIG. 1 and the light having other polarization directions. Therefore, the phase difference between the ordinary ray 11 and the extraordinary ray 12 can be controlled by the spatial light modulator 4.

The two light fluxes of the ordinary ray 11 and the extraordinary ray 12 that have passed through the spatial light modulator 4 are transmitted through the observation object 1 with the phase difference controlled by the spatial light modulator 4. Observation object 1
In other words, the two light fluxes that have transmitted the phase information of the observation object 1 pass through the objective lens 31, enter the Nomarski prism 34, and are superposed. The superposed light fluxes enter the analyzer 33,
Specific polarization direction (direction orthogonal to the transmission axis of the polarizer 22)
Only the luminous flux passes through it.

Due to the luminous flux transmitted through the analyzer 33, interference between the ordinary ray 11 and the extraordinary ray 12 which read the observation object 1 is obtained. This interference is observed by the imaging means 5, whereby an image corresponding to the slope of the phase distribution of the observation object 1 can be obtained, in other words the visualization of the information of the phase object can be achieved.

The image analysis means 6 analyzes the contrast and the brightness value in the image based on the data of the observed object obtained by the image pickup means 5. The parameter determination means 7 is the image analysis means 6
The amount of phase modulation performed by the spatial light modulator 4 is determined based on the analysis result obtained in (1). The spatial light modulator 4 receives the ordinary ray 1 according to the data of the modulation amount determined by the parameter determining means 7.
Control or modulate the phase difference between 1 and the extraordinary ray 12. By this feedback, the observation condition can be changed.

For example, assume that the observed object 1 has the phase distribution shown in FIG. On the other hand, the two light fluxes of the ordinary ray 11 and the extraordinary ray 12 are, as shown in FIG.
The observation object 1 is read at an interval Δ corresponding to the shear amount. When the phase difference between the two light beams is set to 0 in the spatial light modulator 4 as the initial state, the intensity distribution shown in FIG. 4 is obtained. Further, when the spatial light modulator 4 sets the phase difference between the two light beams to −0.8π, the intensity distribution shown in FIG. 5 is obtained. Further, when the phase difference between the two light beams is set to 1.6π in the spatial light modulator 4, the intensity distribution shown in FIG. 6 is obtained. The intensity distribution in FIG. 6 corresponds to the intensity distribution in FIG. 5 inverted. In the intensity distributions of FIGS. 4 to 6, the vertical axis is standardized by the maximum intensity value.

As described above, in the differential interference microscope of this embodiment, the spatial light modulator 4 causes the ordinary ray 11 and the extraordinary ray 12 to pass.
By changing the phase difference between the two, it is possible to easily change the observation condition of the observation object 1 without performing mechanical operation of the Nomarski prism and complicated calculation. Therefore,
In the image analysis means 6 and the parameter determination means 7, by presetting indexes such as contrast and resolution that the observer considers to be optimal, various observations with different physical quantities such as thickness, structure, absorption, etc. Even an object can be easily observed under optimum observation conditions.

Second Embodiment FIG. 7 shows the configuration of the differential interference microscope according to the second embodiment of the present invention. As shown in FIG. 7, the differential interference microscope of the present embodiment superimposes an image of the illumination means 2 that generates two light beams having different polarization directions and the two light beams that have passed through the observation object 1 to form an image. The magnifying optical system 3, the spatial light modulator 4 capable of adjusting the phase difference between the two light beams, the CCD camera 51 which is an image pickup means for picking up an image of the observation object 1, and the image picked up by the CCD camera 51. The image analysis means 6 for analyzing the above, and the parameter determination means 7 for determining the parameters required for the modulation of the spatial light modulator 4 based on the analysis result of the image analysis means 6.

The illumination means 2 comprises a halogen lamp 211,
It has a bandpass filter 212, a polarizer 22, a Nomarski prism 23, and a condenser lens 24. Condenser lens 24 and Nomarski prism 2
3 is arranged so that the front focal plane of the condenser lens 24 and the localization position of the Nomarski prism 23 coincide with each other. The magnifying optical system 3 has an objective lens 31, a Nomarski prism 34, and an imaging lens 35. The objective lens 31 and the Nomarski prism 34 are arranged such that the pupil position of the objective lens 31 and the localized position of the Nomarski prism 34 coincide with each other. The spatial light modulator 4 is a transmissive, homogeneously aligned phase-modulating liquid crystal device 41. The image analysis means 6 and the parameter determination means 7 are configured by software in the computer 150.

The shear directions of the Nomarski prism 23 and the Nomarski prism 34 are parallel to the paper surface of FIG. The planes of polarization of the analyzer 33 and the polarizer 22 are respectively shown in FIG.
The crossed Nicols are arranged at 45 degrees with respect to the paper surface.

The luminous flux emitted from the halogen lamp 211 enters the bandpass filter 212, and the bandpass filter 212 permits only the wavelength component in the vicinity of 670 nm to pass through. The light flux that has passed through the bandpass filter 212 passes through the polarizer 22, so that only the light flux whose polarization direction is 45 degrees with respect to the paper surface of FIG. 7 is the Nomarski prism 23.
Incident on. The light beam incident on the Nomarski prism 23 is separated into an ordinary light beam whose polarization direction is perpendicular to the paper surface of FIG. 7 and an extraordinary light beam whose polarization direction is parallel to the paper surface of FIG. 7. The separated light flux passes through the condenser lens 24 and enters the transmissive homogeneous liquid crystal device 41.

The homogeneously aligned liquid crystal device 41 can modulate the phase only for the ordinary ray whose polarization direction is perpendicular to the plane of the paper of FIG. 7, and the modulation is performed by the computer 150.

The two light fluxes of the ordinary ray 11 and the extraordinary ray 12 which have passed through the homogeneously aligned liquid crystal device 41 respectively pass through two different points of the observed object 1 and the objective lens 31.
And then enters the Nomarski prism 34. Ordinary ray 11 and extraordinary ray 1 incident on the Nomarski prism 34
The two light fluxes are combined again and enter the analyzer 33. In the light flux incident on the analyzer 33, only the component of the polarization direction having a crossed Nicol relationship with the polarization direction of the polarizer 22 is included in the analyzer 33.
Is allowed to pass through.

The light flux that has passed through the analyzer 33 reaches the non-polarizing beam splitter 151 through the imaging lens 35 and is split into two. Non-polarizing beam splitter 151
The light flux reflected at reaches the observer, and the observer directly observes the interference image of the two light fluxes of the ordinary ray 11 and the extraordinary ray 12. On the other hand, the light beam that has passed through the non-polarizing beam splitter 151 enters the CCD camera 51, which is an image pickup means,
The interference image of the two light fluxes of the ordinary ray 11 and the extraordinary ray 12 is C
The image is taken by the CD camera 51.

The observer operates the computer 150 which controls the transmission type homogeneous alignment liquid crystal device 41 on the basis of the observed image to thereby determine the phase difference amount in the homogeneous alignment liquid crystal device 41 while observing the image. It can be operated. As a result, it becomes possible to observe various observation objects in an optimum observation situation.

On the other hand, the image taken by the CCD camera 51 is transmitted to the computer 150. The image data transmitted to the computer 150 is transmitted to the image analysis means 6 composed of software. The image analysis means 6 analyzes the contrast of a region predetermined by the observer as an index of image analysis. The analysis result is transmitted to the parameter determining means 7, the analysis result is compared with the contrast targeted by the observer, and the phase modulation amount is determined so as to approach the target value by using, for example, the least square method. . The phase modulation is performed by the liquid crystal device 41 for phase modulation based on the determined value. Therefore, if the observer sets a target value for the contrast in advance, the observer can automatically perform observation under optimum observation conditions without operating the computer 150 by himself.

In this embodiment, the transmission type homogeneous alignment liquid crystal device 41 is arranged between the condenser lens 24 and the observation object 1. However, the present invention is not limited to this position, and the ordinary ray 11 and the extraordinary ray 12 are provided. May be placed at any position through which

Third Embodiment FIG. 8 shows the configuration of the differential interference microscope according to the third embodiment of the present invention. As shown in FIG. 8, the differential interference microscope of the present embodiment magnifies an image by superimposing an image of the illumination means that generates two light fluxes having different polarization directions and the two light fluxes that have passed through the observation object 1. An optical system, a transmission type homogeneous alignment liquid crystal device 41 which is a spatial light modulator capable of adjusting the phase difference between the two light fluxes, and a CMOS sensor 52 which is an image pickup means for picking up an image of the observation object 1, An image analysis unit 6 for analyzing an image captured by the CMOS sensor 52, and a parameter determination unit 7 for determining a parameter required for modulation of the spatial light modulator 4 based on the analysis result of the image analysis unit 6.
It has and.

In the present embodiment, the illumination means includes a halogen lamp 211, a condenser lens 213, a bandpass filter 212, a polarization beam splitter 214, and a Nomarski prism 23. The magnifying optical system includes an objective lens 31, a Nomarski prism 23,
The polarization beam splitter 214 and the imaging lens 35 are included. Nomarski prism 23 and objective lens 31
Are arranged so that the localization surface of the Nomarski prism 23 and the pupil surface of the objective lens 31 coincide with each other.

The direction of the shear in the Nomarski prism 23 is parallel to the paper surface of FIG. Halogen lamp 211
The bandpass color filter 212 and the polarization beam splitter 214 are arranged such that the polarization direction of the light beam reflected by the polarization beam splitter 214 and incident on the Nomarski prism 23 is 45 degrees with respect to the paper surface of FIG. .

The luminous flux emitted from the halogen lamp 211 enters the bandpass filter 212, and the bandpass filter 212 permits only the wavelength component in the band near 633 nm to pass through. The light beam that has passed through the bandpass filter 212 enters the polarization beam splitter 214, and only the component in the polarization direction of 45 degrees with respect to the paper surface of FIG. 8 is reflected and enters the Nomarski prism 23. The light beam incident on the Nomarski prism 23 is separated into a light beam of an ordinary ray 11 whose polarization direction is perpendicular to the paper surface of FIG. 8 and a light beam of an extraordinary light ray 12 whose polarization direction is parallel to the paper surface of FIG. The separated light flux passes through the objective lens 31 and enters the transmission type homogeneously aligned liquid crystal device 41.

The homogeneously oriented liquid crystal device 41 can modulate the phase only for the ordinary ray whose polarization direction is perpendicular to the plane of the paper of FIG. 8, and the modulation is controlled by the computer 150.
It is performed by the signal from.

The two light fluxes of the ordinary ray 11 and the extraordinary ray 12 which have passed through the homogeneously aligned liquid crystal device 41 are incident on the observation object 1 which is a reflection object, and the information is read and reflected. The two light fluxes of the ordinary ray 11 and the extraordinary ray 12 which have been reflected enter the liquid crystal device 41 of homogeneous alignment again,
Receive the same modulation again. The two light fluxes of the ordinary ray 11 and the extraordinary ray 12 which have been subjected to the modulation enter the Nomarski prism 23, are superposed and are combined into one light flux, and enter the polarization beam splitter 214. The light beam incident on the polarization beam splitter 214 is
Only the component of the polarization direction which is reflected by the light beam and becomes crossed Nicol is allowed to pass through the polarization beam splitter 214. The light beam that has passed through the polarization beam splitter 214 passes through the imaging lens 35 and is placed on the surface on which the magnified image is formed.
The light enters the S sensor 52, and the differential interference image of the observation object 1 is captured by the CMOS sensor 52.

The image obtained by the CMOS sensor 52 is displayed on a display (not shown) via the computer 150.

On the other hand, in the computer 150, the information of the image obtained by the CMOS sensor 52 is transmitted to the software which is the image analysis means 6. In this image analysis means 6, the brightness value and the resolution in a specific area in the image are measured as an index predetermined by the observer. The measured value is transmitted to the parameter determination means 7, and the phase amount modulated by the transmission type homogeneous alignment liquid crystal device 41 is determined using a neural network so that the measured value approaches the target value set by the observer. A signal for modulating the determined phase is transmitted to the liquid crystal device 41. By repeating such optimum feedback, it is possible to automatically obtain an image of the optimum brightness value desired by the observer.

In this embodiment, the transmission type homogeneous alignment liquid crystal device 41 is disposed between the objective lens 31 and the observation object 1, but the position is not limited to this, and the ordinary ray 11 is used. It may be arranged at any position where the extraordinary ray 12 passes.

Fourth Embodiment FIG. 9 shows the configuration of the differential interference microscope according to the third embodiment of the present invention. As shown in FIG. 9, the differential interference microscope of the present embodiment magnifies an image by superimposing an image of the two light fluxes that have passed through the observation object 1 with the illumination means that generates two light fluxes having different polarization directions. An optical system, a reflective homogeneous alignment liquid crystal device 42 which is a spatial light modulator capable of adjusting the phase difference between the two light beams, and a CCD camera 51 which is an image pickup means for picking up an image of the observation object 1. The image analysis unit 6 analyzes the image captured by the CCD camera 51, and the parameter determination unit 7 determines the parameter required for the modulation of the spatial light modulator 4 based on the analysis result of the image analysis unit 6. .

In this embodiment, the illumination means includes a light emitting diode (LED) 216, a polarizer 22, a condenser lens 213, a non-polarizing beam splitter 217, and a Nomarski prism 23. The magnifying optics
It includes an objective lens 31, a Nomarski prism 23, a polarization beam splitter 214, an analyzer 33, and an imaging lens 35.

The direction of the shear in the Nomarski prism 23 is parallel to the paper surface of FIG. The Nomarski prism 23 and the objective lens 31 are arranged so that the localization surface of the Nomarski prism 23 and the pupil plane of the objective lens 31 coincide with each other.

The light beam emitted from the LED 216 enters the polarizer 22, and only the component in the polarization direction of 45 degrees with respect to the paper surface of FIG. 9 is allowed to pass. The light flux transmitted through the polarizer 22 enters the non-polarization beam splitter 217 via the condenser lens 213. Non-polarizing beam splitter 21
The light beam reflected at 7 enters the Nomarski prism 23 and is separated into two light beams, an ordinary ray 11 and an extraordinary ray 12, whose polarization directions are orthogonal to each other. These two separated light fluxes pass through the transmission-type observation object 1 through the objective lens 31, and then enter the reflection-type homogeneous type liquid crystal device 42.

Reflective homogeneous liquid crystal device 4
In No. 2, the phase can be modulated only for a light beam whose polarization direction is perpendicular to the plane of FIG. That is, the reflective homogeneous type liquid crystal device 42 changes the phase amount of the ordinary ray 11 and reflects it.

Reflective homogeneous liquid crystal device 4
The light flux reflected by 2 again passes through the observation object 1 and enters the objective lens 31. The two light fluxes that have passed through the objective lens 31 enter the Nomarski prism 23, and are superimposed and combined into a single light flux. The combined light flux passes through the non-polarization beam splitter 217 and enters the analyzer 33. The light flux incident on the analyzer 33 is allowed to pass only the component whose polarization direction is crossed Nicols with respect to the polarizer 22. The light flux transmitted through the analyzer 33 is imaged by the imaging lens 35, and the differential interference image of the observation object 1 is captured by the CCD camera 51 arranged on the imaging surface.

The image obtained by the CCD camera 51 is transmitted to the computer 150 and displayed on a display (not shown).

On the other hand, in the computer 150, C
The image obtained by the CD camera 51 is sent to the image analysis means 6 composed of software and analyzed. The image analysis unit 6 analyzes the contrast and the brightness value of the specific region as an index preset by the observer, and the analysis result is transmitted to the parameter determination unit 7. The parameter determining means 7 compares the contrast and the brightness value preset by the observer with the analysis result, determines the amount of phase modulated by the homogeneous type liquid crystal device 42 using a neural network, and determines the determined phase. Is transmitted to the liquid crystal device 42. By repeating this operation, the target values set for the contrast and brightness values are automatically set, and observation can be performed under optimal observation conditions.

Further, when the phase amount is changed variously, the image analysis means 6 also restores the phase distribution of the observed object 1 based on the image obtained by the CCD camera 51.

An algorithm for restoring the phase distribution of the observed object 1 will be described with reference to the flowchart of FIG.
As an initial value, the desired phase distribution f (i, j) (i, j:
An integer) is a random phase distribution, and an image Iφ0 (i, j) observed when a phase difference φ0 is given, a shear amount Δx, and an arbitrary position (i0, j0) in the image where the phase value is changed. A change amount Δf is given. Under given conditions, the phase distribution f
The interference image IC (i, j) in the case of (i, j) is calculated, and the calculation result IC (i, j) and the experimental result Iφ0 (i, j
j) is compared. For comparison, the sum (S _k = Σ | IC _ij −I) in the absolute value of the difference between the pixels of each image is used.
φ0 _ij | (k: integer)) is calculated. This sum Sk is compared with the value S _k-1 calculated with the amount of change Δf last time, and if it is larger than the predetermined set value V, the next amount of change Δf is calculated using the least square method or the like and selected. The same calculation is performed by adding Δf to the phase at the position (i0, j0). On the other hand, if the absolute values of S _k and S _k-1 are smaller than the set value V, then the other pixels i0 and j0 are selected and the calculation is repeated. Since S _k-1 does not exist in the initial state, Δf to be updated is given in advance. When this calculation is performed for all pixels, the calculation is repeated next for another phase difference φ1. By repeating the calculation in this manner, the phase distribution of the observed object can be restored.

In the second to fourth embodiments, an example in which a liquid crystal device of homogeneous alignment which is currently most used and which is electrically controlled is used for the spatial light modulator 4, but the spatial light modulator 4 is used. As the device, not only an electrically-addressed device that electrically controls but also an optically-addressed device that optically controls may be used. Further, the spatial light modulator 4 has a liquid crystal having homeotropic alignment or hybrid alignment, a crystal such as LiNb03, an organic photorefractive material, a photochromic material, or the like. A spatial light modulator using an element capable of controlling the above may be used.

The light source is not limited to the above embodiment. Further, the prism is not limited to the Nomarski prism, and any prism having birefringence can be applied.

The method of restoring the phase distribution is not limited to the above-mentioned example, and it is obvious that the method using the neural network and the methods so far can be applied in the same manner.

Although some embodiments have been specifically described with reference to the drawings, the present invention is not limited to the above-described embodiments, and is performed without departing from the scope of the invention. Includes all implementations.

[0054]

According to the present invention, there is provided a differential interference microscope in which observation conditions can be easily changed without requiring complicated operations. As a result, it becomes possible to observe various observation objects under optimum observation conditions.

[Brief description of drawings]

FIG. 1 shows a configuration of a differential interference microscope according to a first embodiment of the present invention.

FIG. 2 shows an example of a phase distribution of an observation object.

FIG. 3 shows phase distributions of an ordinary ray and an extraordinary ray obtained by reading the observation object of FIG.

4 shows the intensity distribution when the phase difference between the ordinary ray and the extraordinary ray obtained by reading the observation object of FIG. 2 is zero.

5 shows an intensity distribution when the phase difference between the ordinary ray and the extraordinary ray obtained by reading the observation object of FIG. 2 is −0.8π.

6 shows an intensity distribution when the phase difference between the ordinary ray and the extraordinary ray obtained by reading the observation object of FIG. 2 is 1.6π.

FIG. 7 shows a configuration of a differential interference microscope according to a second embodiment of the present invention.

FIG. 8 shows a configuration of a differential interference microscope according to a third embodiment of the present invention.

FIG. 9 shows a configuration of a differential interference microscope according to a fourth embodiment of the present invention.

FIG. 10 is a flowchart showing a phase distribution restoration method.

FIG. 11 shows a configuration of a differential interference microscope of a conventional example.

[Explanation of symbols]

2 lighting means 3 magnifying optical system 4 Spatial light modulator 5 Imaging means 6 Image analysis means 7 Parameter determination means 21 light source 22 Polarizer 23 Nomarski Prism 24 Condenser lens 31 Objective lens 33 Analyzer 34 Nomarski Prism 35 Imaging lens

Continued front page    F term (reference) 2F064 CC00 EE10 FF03 GG23 GG33                       GG34 GG42 GG53 HH03 HH08                       KK01                 2H052 AA05 AC01 AC04 AC05 AC33                       AD31 AF14 AF25                 2H088 EA37 FA11 HA18 HA20 HA28                       MA20                 2H091 FA07X FA07Z FA08X FA08Z                       FA10X FA21X FA26X FA41Z                       LA30

Claims (7)

[Claims] 1. A differential interference microscope for observing an observation object by irradiating a plurality of light fluxes having different polarization directions, and an illuminating unit for generating a plurality of light fluxes having different polarization directions irradiating the observation object, and the observation object. An optical system that forms a plurality of light fluxes having different polarization directions from the illuminating means that are overlapped with each other and forms an image of the observation object on an image forming plane, and a plurality of different polarization directions that are generated by the illuminating means. A differential interference microscope, comprising: a spatial light modulator capable of adjusting a relative phase difference between light beams by a signal from the outside. 2. The illuminating means includes a light source and an optical element for converting a light beam from the light source into a plurality of light beams having different polarization directions, and the optical system has different polarization directions via the observation object. The differential interference microscope according to claim 1, further comprising an optical element that synthesizes a plurality of light fluxes. 3. The differential interference microscope according to claim 1, wherein the spatial light modulator uses liquid crystal. 4. An image pickup unit for picking up an image of the observation object generated on the image plane, an image analysis unit for analyzing characteristics of the image picked up by the image pickup unit, and an analysis result of the image analysis unit. Based on, further comprising a parameter determination means for determining a parameter required for modulation of the spatial light modulator, by the parameters determined by the parameter determination means,
The differential interference microscope according to any one of claims 1 to 3, wherein the spatial light modulator is configured to be controlled. 5. The differential interference microscope according to claim 4, wherein the image analysis means includes at least a physical quantity relating to contrast or resolution as an analysis target. 6. The parameter determining means determines a parameter used for controlling the modulating means based on a predetermined function having a physical quantity analyzed by the image analyzing means as a variable. Alternatively, the differential interference microscope according to claim 5. 7. The spatial light modulator adjusts the relative phase difference between a plurality of light fluxes having different polarization directions a plurality of times by changing the relative phase difference at each time, and the image is picked up by the image pickup means at each time. The differential interference microscope according to any one of claims 4 to 6, wherein the phase distribution of the observation object can be restored based on an image.