Focus detecting device for an optical apparatus

A focus detecting device for a microscope comprising:

• a multi-beam producing member for emitting a plurality of light beams;
• a light-blocking member for blocking a part of said plurality of light beams;
• a beam splitting member having a surface for reflecting or transmitting an incident light beam;
• a light-condensing optical system for condensing an incident light beam;
• a photodetector having at least two light-receiving sections;
• and
• a beam adjusting mechanism for changing an amount of the plurality of light beams produced by said multi-beam producing member and a spacing between said light beams,
• wherein said beam adjusting mechanism has a beam restriction member and a moving mechanism for moving said beam restriction member to a position where a light beam is converged, and
• wherein said multi-beam producing member and said light-blocking member are placed on a first optical path, said light-condensing optical system and said photodetector are placed on a second optical path, said beam splitting member is located at an intersection of an optical axis of said first optical path with an optical axis of said second optical path, said photodetector is located at a position on which a light beam is converged by said light-condensing optical system.

A focus detecting device for an optical apparatus comprising:

• a multi-beam producing member for emitting a plurality of light beams, said multi-bam producing member being placed in a first optical path and having a light source and a diffraction optical element;
• a light-blocking member that is placed in the first optical path and blocks a part of said plurality of light beams;
• a beam splitting member that has a surface for reflecting or transmitting an incident light beam and is located at an intersection or an optical axis of the first optical path with an optical axis of a second optical path;
• a light-condensing optical system that is placed in the second optical path and condenses an incident light beam;
• a photodetector that has at least two light-receiving sections and is placed in the second optical path at a position on which a light beam is converged by said light-condensing optical system;
• a first driving mechanism configured and arranged to move said diffraction optical element so that said diffraction optical element is movable in said first optical path;
• and
• at least another one diffraction optical element,
• wherein said light source is provided with only one light-emitting section for emitting a single light beam,
• wherein said light-condensing optical system is disposed between said beam splitting member and said photodetector, and
• wherein said diffraction optical element and said at least another one diffraction element are movable in said first optical path.

A focus detecting device for an optical apparatus comprising:

• a multi-beam producing member for emitting a plurality of light beams;
• a light blocking member for blocking a part of said plurality of light beams;
• a beam splitting member having a surface for reflecting or transmitting an incident light beam;
• a light-condensing optical system for condensing an incident light beam;
• a photodetector having at least two light-receiving sections;
• a relay optical system configured and arranged to collect said plurality of light beams;
• a beam restriction member located at a position on which light is converged by said relay optical system;
• and
• a second driving mechanism constructed and arranged to move said beam restriction member in an optical path,
• wherein said multi-beam producing member and said light-blocking member are placed in a first optical path, said light-condensing optical system and said photodetector are placed on a second optical path, said beam splitting member is located at an intersection of an optical axis of said first optical path with an optical axis of said second optical path, said photodetector is located at a position on which a light beam is converged by said light-condensing optical system, and said light-condensing optical system is disposed between said beam splitting member and said photodetector.

A focus detecting device for an optical apparatus comprising:

• a multi-beam producing member for emitting a plurality of light beams, said multi-beam producing member being placed in a first optical path and having a light source and a diffraction optical element;
• a light-blocking member that is placed in the first optical path and blocks a part of said plurality of light beams;
• a beam splitting member that has a surface for reflecting or transmitting an incident light beam and is located at an intersection of an optical axis of the first optical path with an optical axis of a second optical path;
• a light-condensing optical system that is placed in the second optical path and condenses an incident light beam;
• a photodetector that has at least two light-receiving sections and is placed in the second optical path at a position on which a light beam is converged by said light-condensing optical system;
• a first driving mechanism configured and arranged to move said diffraction optical element so that said diffraction optical element is movable in said first optical path;
• an intensity attenuation member configured and arranged to reduce an intensity of an incident light beam;
• and
• a third driving mechanism constructed and arranged to move said intensity attenuation member,
• wherein said light source is provided with only one light-emitting section for emitting a single light beam,
• wherein said light-condensing optical system is disposed between said beam splitting member and said photodetector, and
• wherein when said diffraction optical element is inserted in said first optical path, said intensity attenuation member is removed from said first optical path, and when said diffraction optical element is removed from said first optical path, said intensity attenuation member is inserted in said first optical path.

A focus detecting device for an optical apparatus comprising:

• a multi-beam producing member for emitting a plurality of light beams;
• a light-blocking member for blocking a part of said plurality of light beams;
• a beam splitting member having a surface for reflecting or transmitting an incident light beam;
• a light-condensing optical system for condensing an incident light beam;
• a photodetector having at least two light-receiving sections;
• and
• a beam adjusting mechanism for changing an amount of a plurality of light beams produced by said multi-beam producing member or a spacing between said light beams,
• wherein said multi-beam producing member and said light-blocking member are placed in a first optical path, said light-condensing optical system and said photodetector are placed in a second optical path, said beam splitting member is located at an intersection of an optical axis of said first optical path with an optical axis of said second optical path, said photodetector is located at a position on which a light beam is converged by said light-condensing optical system, and said light-condensing optical system is disposed between said beam splitting member and said photodetector, and
• wherein said multi-beam producing member is provided with a plurality of diffraction optical elements, and said beam adjusting mechanism has a moving mechanism for placing one of said plurality of diffraction optical elements in said first optical path.

A focus detecting device for an optical apparatus comprising:

• a multi-beam producing member for emitting a plurality of light beams;
• a light-blocking member for blocking a part of said plurality of light beams;
• a beam splitting member having a surface for reflecting or transmitting an incident light beam;
• a light-condensing optical system for condensing an incident light beam;
• a photodetector having at least two light-receiving sections;
• and
• a beam adjusting mechanism for changing an amount of a plurality of light beams produced by said multi-beam producing member or a spacing between said light beams,
• wherein said multi-beam producing member and said light-blocking member are placed in a first optical path, said light-condensing optical system and said photodetector are placed in a second optical path, said beam splitting member is located at an intersection of an optical axis of said first optical path with an optical axis of said second optical path, said photodetector is located at a position on which a light beam is converged by said light-condensing optical system, and said light-condensing optical system is disposed between said beam splitting member and said photodetector, and
• wherein said beam adjusting mechanism has a beam restriction member and a moving mechanism for moving said beam restriction member to a position where a light beam is converged.