Differential interference microscope apparatus and an observing method using the same apparatus

Claim 1

A differential interference microscope apparatus comprising: a light source; a condenser optical system for condensing beams of flight from said light source and illuminating an object with the beams of light; an objective optical system for converging the beams of light from the illuminated object and forming an image of the object; a pick-up device for photoelectrically detecting the image of the object; and a contrast enhancement circuit for enhancing a contrast of the image on the basis of an output signal of the image of the object photoelectrically detected by said pick-up device, wherein the following elements are disposed sequentially from the side of said light source in an optical path between said light source and the object, said elements being: a first polarizing element for changing a beam of light from said light source into a predetermined beam of polarized light; and a first birefringent element for separating the beam of polarized light into an ordinary ray beam including an ordinary ray and a corresponding extraordinary ray beam including an extraordinary ray, the ordinary ray beam and corresponding extraordinary ray beam being guided to pass through the object; wherein the following elements are disposed sequentially from the side of the object in an optical path between the object and the image, said elements being: a second birefringent element for guiding the ordinary ray beam and corresponding extraordinary ray beam which mass through the object, onto the same optical path; and a second polarizing element for causing the ordinary ray beam and corresponding extraordinary ray beam guided onto the same optical path to interfere with each other, and wherein the shear quantity S between the ordinary ray of the ordinary ray beam and the extraordinary ray of the corresponding extraordinary ray beam satisfies the following condition: δ/20≦S<δ/2 where δ is the resolving power of said objective optical system.

Claim 8

A method of observing an object by use of a differential interference microscope apparatus which includes an objective optical system having a corresponding resolving power, the method comprising the steps of: a first step of converting a beam of light from a light source into a predetermined beam of polarized light; a second step of separating the predetermined beam of polarized light into an ordinary ray beam including an ordinary ray and a corresponding extraordinary ray beam including an extraordinary ray; a third step of irradiating the object with the ordinary ray beam and corresponding extraordinary ray beam, to pass the ordinary ray beam and corresponding extraordinary ray beam through the object; a fourth step of guiding the ordinary ray beam and corresponding extraordinary ray beam passing through the object onto the same optical path; a fifth step of causing the ordinary ray beam and corresponding extraordinary ray beam guided onto the same optical path to interfere with each other; a sixth step of forming an image of the object on the basis of the ordinary ray beam and corresponding extraordinary ray beam interfered with each other by converging action of said objective optical system; a seventh step of photoelectrically converting the formed image; and an eighth step of enhancing a contrast of the image on the basis of an output of the photoelectrically converted image, wherein the shear quantity S between the ordinary ray of the ordinary ray beam and the extraordinary ray of the corresponding extraordinary ray beam satisfies the following condition: δ/20≦S<δ/2 where δ is the resolving power of said objective optical system.

Claim 9

A method of observing an object by use of a differential interference microscope apparatus which includes an objective optical system having a corresponding resolving power, the method comprising the steps of: a first step of converting a beam of light from a light source into a predetermined beam of polarized light; a second step of separating the predetermined beam of polarized light into an ordinary ray beam including an ordinary ray and a corresponding extraordinary ray beam including an extraordinary ray; a third step of irradiating the object with the ordinary ray beam and corresponding extraordinary ray beam, to pass the ordinary ray beam and corresponding extraordinary ray beam through the object; a fourth step of guiding the ordinary ray beam and corresponding extraordinary ray beam passing through the object onto the same optical path; a fifth step of causing the ordinary ray beam and corresponding extraordinary ray beam guided onto the same optical path to interfere with each other; a sixth step of forming an image of the object on the basis of the ordinary ray beam and corresponding extraordinary ray beam interfered with each other by converging action of said objective optical system; a seventh step of photoelectrically converting the formed image; and an eighth step of enhancing a contrast of the image on the basis of an output of the photoelectrically converted image, wherein the shear quantity S between the ordinary ray of the ordinary ray beam and the extraordinary ray of the corresponding extraordinary ray beam satisfies the following condition: δ/20≦S<δ/2 where δ is the resolving power of said objective optical system.

Claim 12

A method of observing an object via the use of an objective optical system, comprising the steps of: projecting a beam of light; condensing the projected beam of light; changing the condensed beam of light into a beam of polarized light; separating the beam of polarized light into an ordinary ray beam including an ordinary ray and a corresponding extraordinary ray beam including an extraordinary ray; guiding the ordinary ray beam and corresponding extraordinary ray beam to pass through the object; using an objective optical system to condense the ordinary ray beam and corresponding extraordinary ray beam passing through the object; guiding the ordinary ray beam and corresponding extraordinary ray beam condensed by the objective optical system, onto the same optical path; causing the ordinary ray beam and corresponding extraordinary ray beam guided onto the same optical path to interfere with each other and form an image of the object; photoelectrically detecting the image of the object formed by the ordinary ray beam and corresponding extraordinary ray beam; and enhancing the contrast of the detected image, wherein the shear quantity S between the ordinary ray of the ordinary ray beam and the extraordinary ray of the corresponding extraordinary ray beam satisfies the following condition: δ/20≦S<δ/2 where δ is the resolving power of the objective optical system.

Claim 13

A method of observing an object via the use of an objective optical system, comprising the steps of: projecting a beam of light; condensing the projected beam of light; changing the condensed beam of light into a beam of polarized light; separating the beam of polarized light into an ordinary ray beam including an ordinary ray and a corresponding extraordinary ray beam including an extraordinary ray; guiding the ordinary ray beam and corresponding extraordinary ray beam to pass through the object; using an objective optical system to condense the ordinary ray beam and corresponding extraordinary ray beam passing through the object; guiding the ordinary ray beam and corresponding extraordinary ray beam condensed by the objective optical system, onto the same optical path; causing the ordinary ray beam and corresponding extraordinary ray beam guided onto the same optical path to interfere with each other and form an image of the object; photoelectrically detecting the image of the object formed by the ordinary ray beam and corresponding extraordinary ray beam; and enhancing the contrast of the detected image, wherein the shear quantity S between the ordinary ray of the ordinary ray beam and the extraordinary ray of the corresponding extraordinary ray beam satisfies the following condition: δ/20≦S<δ/2 where δ is the resolving power of the objective optical system.

Claim 16

A method of observing an object via the use of an objective optical system, comprising the steps of: forming an ordinary ray beam including an ordinary ray and a corresponding extraordinary ray beam including an extraordinary ray, from a light beam projected by a light source; passing the ordinary ray beam and the corresponding extraordinary ray beam through the object; using the objective optical system to condense the ordinary ray beam and corresponding extraordinary ray beam passing through the object, to form an image of the object; and enhancing the contrast of the formed image, wherein the shear quantity S between the ordinary ray of the ordinary ray beam and the extraordinary ray of the corresponding extraordinary ray beam satisfies the following condition: δ/20≦S<δ/2 where δ is the resolving power of the objective optical system.

Claim 17

A method of observing an object via the use of an objective optical system, comprising the steps of: forming an ordinary ray beam including an ordinary ray and a corresponding extraordinary ray beam including an extraordinary ray, from a light beam projected by a light source; passing the ordinary ray beam and the corresponding extraordinary ray beam through the object; using the objective optical system to condense the ordinary ray beam and corresponding extraordinary ray beam passing through the object, to form an image of the object; and enhancing the contrast of the formed image, wherein the shear quantity S between the ordinary ray of the ordinary ray beam and the extraordinary ray of the corresponding extraordinary ray beam satisfies the following condition: δ/20≦S<δ/2 where δ is the resolving power of the objective optical system.