Two-dimensional positioning apparatus with optical sensors aligned to avoid interference

A positioning apparatus adapted to perform positioning of a movable second member relative to a stationary first member only in respect of an X direction and a Y direction perpendicular to each other comprising:

• X-direction moving means for moving said second member only in said X direction;
• Y-direction moving means for moving said second member only in said Y direction;
• a first optical sensor for detecting a predetermined position of said movable second member relative to said stationary first member in said X direction and delivering a first detection signal in response thereto,
• said first optical sensor having one of a light projector and a light receiver separately arranged on said first member and the other of said light projector and light receiver arranged on said second member such that said light projector and said light receiver of said first optical sensor are opposed to each other in said Y direction when said second member is in said predetermined position in respect of said X direction;
• a second optical sensor for detecting a predetermined position of said movable second member relative to said stationary first member in said Y direction and delivering a second detection signal in response thereto,
• said second optical sensor having one of a light projector and a light receiver separately arranged on said first member and the other of said light projector and light receiver arranged on said second member such that said light projector and said light receiver of said second optical sensor are opposed to each other in said X direction, when said second member is in said predetermined position in respect of said Y direction;
• and
• control means receiving said first and second detection signals from said first and second optical sensors for stopping a moving operation of said X-direction moving means upon receiving said first detection signal from said first optical sensor upon said second member reaching said predetermined position in the X-direction and for stopping a moving operation of said Y-direction moving means upon receiving said second detection signal from said second optical sensor upon said second movable member reaching said predetermined position in said Y-direction.