Illuminating system, projection apparatus and detecting apparatus

A projection apparatus comprising:

• a light source;
• a fly's eye lens;
• a relay optical system;
• an optical path split element;
• a reflection type light valve;
• and
• an imaging optical system,
• wherein said relay optical system is disposed so that a normal line of said reflection type light valve is parallel to an optical axis of said relay optical system,
• said reflection type light valve and a screen are conjugate with respect to said imaging optical system, and
• light beams from said light source travel through said fly's eye lens, said optical path split element and said relay optical system and also, after being reflected by said reflection type light valve, travel through said relay optical system, said optical path split element and said imaging optical system.

A projection apparatus comprising:

• a reflection type light valve;
• a light source;
• a fly's eye lens disposed in light beams from said light source;
• a relay optical system having an optical axis parallel to a normal line of said reflection type light valve, for guiding the light beams emerging from said fly's eye lens to said reflection type light valve;
• and
• an imaging optical system through which said reflection type light valve is conjugate to a screen.

An illuminating system comprising:

• a light source;
• a fly's eye lens having a plurality of lens elements;
• an optical path split element having a light split surface disposed in focal positions of said plurality of lens elements;
• and
• a relay optical system,
• wherein an optical distance along the optical axis between the light split surface and said relay optical system and an optical distance along the optical axis between said relay optical system and an illuminated object are coincident with a focal length of said relay optical system, and
• only portions, corresponding to the focal positions of said plurality of lens elements, on the light split surface direct the light beams emerging from said fly's eye lens.

A detecting apparatus with an illuminating system, comprising:

• a light source;
• a fly's eye lens having a plurality of lens elements;
• an optical path split element having a light split surface disposed in focal positions of said plurality of lens elements;
• a relay optical system;
• and
• a detector,
• wherein an optical distance along the optical axis between the light split surface and said relay optical system and an optical distance along the optical axis between said relay optical system and an illuminated object are coincident with a focal length of said relay optical system,
• the light beams emerging from said fly's eye lens are directed by only portions, corresponding to the focal positions of said plurality of lens elements, on the light split surface, and
• reflected light beams from the illuminated object are directed by areas different from the portions on the light split surface and are guided to said detector.