Phase contrast microscope
First Claim
1. A phase contrast microscope comprising:
- an illumination optical system for illuminating a specimen under inspection;
an aperture arranged at a pupil of said illumination optical system;
an imaging optical system for forming an image of the specimen;
a phase plate arranged near a pupil of said imaging optical system, said pupil of the imaging optical system being arranged at a conjugate position with said aperture with respect to a specimen plane on which said specimen situates;
an image pick-up means provided at a imaging plane on which an image of the specimen is formed by said imaging optical system for picking-up the image to produce an image signal;
a storing means for storing said image signal produced by said image pick-up means; and
a signal processing means for processing the image signal read out of said storing means;
wherein said phase plate is constructed to give phase differences which have substantially a same amount but have opposite signs, two images at said different phase differences are separately picked-up by said image pick-up means and stored in said storing means, an image of a difference between said two images is derived as a phase contrast image, said phase plate comprises a liquid crystal and substantially transparent electrodes arranged on both sides of said liquid crystal, and a voltage applied to the liquid crystal via the electrodes is changed such that said phase differences having substantially the same amount but having said opposite signs are obtained.
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Accused Products
Abstract
A phase contrast microscope including an illuminating optical system, a ring slit arranged at a pupil of the illuminating optical system, an imaging optical system, and a phase plate arranged at a pupil of the imaging optical system which is conjugate with the pupil of the illuminating optical system with respect to a specimen plane on which a specimen under inspection is placed. The phase plate is formed by a liquid crystal and a pair of transparent ring-shaped electrodes arranged on both sides of the liquid crystal. A voltage applied across the liquid crystal via the electrodes is changed such that a phase difference introduced by the phase plate is set to ±π/2 to obtain a dark contrast image and a bright contrast image. A difference between these dark and bright contrast images is derived to obtain a phase contrast image having high contrast and resolution.
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Citations
21 Claims
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1. A phase contrast microscope comprising:
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an illumination optical system for illuminating a specimen under inspection; an aperture arranged at a pupil of said illumination optical system; an imaging optical system for forming an image of the specimen; a phase plate arranged near a pupil of said imaging optical system, said pupil of the imaging optical system being arranged at a conjugate position with said aperture with respect to a specimen plane on which said specimen situates; an image pick-up means provided at a imaging plane on which an image of the specimen is formed by said imaging optical system for picking-up the image to produce an image signal; a storing means for storing said image signal produced by said image pick-up means; and a signal processing means for processing the image signal read out of said storing means; wherein said phase plate is constructed to give phase differences which have substantially a same amount but have opposite signs, two images at said different phase differences are separately picked-up by said image pick-up means and stored in said storing means, an image of a difference between said two images is derived as a phase contrast image, said phase plate comprises a liquid crystal and substantially transparent electrodes arranged on both sides of said liquid crystal, and a voltage applied to the liquid crystal via the electrodes is changed such that said phase differences having substantially the same amount but having said opposite signs are obtained. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A phase contrast microscope comprising:
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an illumination optical system for illuminating a specimen under inspection; an aperture arranged at a pupil of said illumination optical system; an imaging optical system for forming an image of the specimen; a phase plate arranged near a pupil of said imaging optical system, said pupil of the imaging optical system being arranged at a conjugate position with the aperture with respect to a specimen plane on which said specimen situates, said phase plate including an element which introduces an electrically variable phase difference between a zero order diffracted beam and higher order diffracted beams, and substantially transparent electrodes arranged on opposite sides of said element such that a voltage is applied across the element via the electrodes; and a controlling means for adjusting a value of said voltage applied across said element to set said phase difference to such values that a dark contrast image, a bright contrast image and a high resolution image are selectively observed under a same condition. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A phase contrast microscope comprising:
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an illumination optical system for illuminating a specimen under inspection, the specimen being disposed at a specimen plane; an aperture arranged at a pupil of said illumination optical system; an imaging optical system for forming an image of the specimen at an imaging plane; a phase plate arranged near a pupil of said imaging optical system, said pupil of the imaging optical system being arranged at a conjugate position with said aperture with respect to the specimen plane; an image pick-up means provided at the imaging plane for picking-up the image to produce an image signal; a storing means for storing said image signal produced by said image pick-up means; and a signal processing means for processing the image signal read out of said storing means; wherein said phase plate is constructed to give phase differences which have substantially a same amount but have opposite signs, two images at said phase differences comprising a dark contrast image having an intensity distribution Ia and a bright contrast image having an intensity distribution Ib and are separately picked-up by said image pick-up means and stored in said storing means, and an image of a difference between said two images is derived as a phase contrast image having an intensity distribution Ia-Ib. - View Dependent Claims (18)
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19. A phase contrast microscope comprising:
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an illumination optical system for illuminating a specimen under inspection, the specimen being disposed at a specimen plane; an aperture arranged at a pupil of said illumination optical system; an imaging optical system for forming an image of the specimen at an imaging plane; a phase plate arranged near a pupil of said imaging optical system, said pupil of the imaging optical system being arranged at a conjugate position with said aperture with respect to the specimen plane, said phase plate comprising a liquid crystal and substantially transparent electrodes arranged on both sides of the liquid crystal; an image pick-up means provided at the imaging plane for picking-up the image to produce an image signal; a storing means for storing said image signal produced by said image pick-up means; and a signal processing means for processing the image signal read out of said storing means; wherein said phase plate is constructed to give phase differences which have substantially a same amount but have opposite signs, two images at said different phase differences are separately picked-up by said image pick-up means and stored in said storing means, an image of a difference between said two images is derived as a phase contrast image, at least one of said transparent electrodes of the phase plate is formed as a ring and a ratio of a radius r of a center circle of the ring and a radius R of the pupil of the imaging optical system is set to 1>
r/R>
0.5.
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20. A phase contrast microscope comprising:
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an illumination optical system for illuminating a specimen under inspection, the specimen being disposed at a specimen plane; an aperture arranged at a pupil of said illumination optical system; an imaging optical system for forming an image of the specimen at an imaging plane; a phase plate arranged near a pupil of said imaging optical system, said pupil of the imaging optical system being arranged at a conjugate position with said aperture with respect to the specimen plane; an image pick-up means provided at the imaging plane for picking-up the image to produce an image signal; a storing means for storing said image signal produced by said image pick-up means; a signal processing means for processing the image signal read out of said storing means to produce a phase contrast image; and a calculating means for effecting a deconvolution of the phase contrast image obtained by said signal processing means; wherein said phase plate is constructed to give phase differences which have substantially a same amount but have opposite signs, two images at said different phase differences are separately picked-up by said image pick-up means and stored in said storing means, and an image of a difference between said two images is derived as said phase contrast image. - View Dependent Claims (21)
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Specification