Object distance measuring device in camera

Abstract

An object distance measuring device in a camera, including an active object distance measuring mechanism for emitting measuring light toward an object to be photographed and receiving the measuring light as reflected by the object to detect the object distance is provided. A measuring zone is provided in a finder to indicate a measuring position at which the measurement of the object distance by the active object distance measuring mechanism is effected. A device is provided for varying the position of the measuring zone in the finder, and a device for varying the direction of the emission of the measuring light by the active object distance measuring mechanism in accordance with the varied position of the measuring zone is also provided.

We claim: 
     
       1. An object distance measuring device in a camera, comprising: an object distance measuring unit having a light emitter which emits measuring light toward an object to be photographed and a light receiver which receives the measuring light as reflected by the object;   a direction varying mechanism for varying the direction of said object distance measuring unit;   measuring position varying means for varying the position of a measuring zone in a field of view finder; and   object distance measuring unit controlling means for controlling said object distance measuring unit to follow the movement of said measuring zone by said measuring position varying means, thereby to change the direction of said object distance measuring unit.   
     
     
       2. An object distance measuring device according to claim 1, wherein said light emitter comprises an infrared light emitting element. 
     
     
       3. An object distance measuring device according to claim 1, wherein said light receiver comprises an infrared light receiving element. 
     
     
       4. An object distance measuring device according to claim 3, wherein said light receiving element is a position sensitive device. 
     
     
       5. An object distance measuring device according to claim 1, wherein said object distance measuring unit comprises a frame body which supports said light emitter said light receiver. 
     
     
       6. An object distance measuring device according to claim 5, wherein said direction varying mechanism comprises a frame body supporting bracket which supports said frame body for rotation about .[.two orthogonal axes.]. .Iadd.a first axis .Iaddend., .[.and.]. .Iadd.said frame body supporting bracket being rotatable about a second axis which is orthogonal to said first axis, a .Iaddend.a first .Iadd.motor for rotating said frame body about said first axis,.Iaddend.and .Iadd.a .Iaddend.second .[.motors.]. .Iadd.motor .Iaddend.for rotating said frame body supporting bracket .[.around the two orthogonal axes.]. .Iadd.and said frame body about said second axis .Iaddend.. 
     
     
       7. An object distance measuring device according to claim 1, wherein said measuring position varying means comprises a Y-direction movable plate which is movable in a Y-direction and which includes said measuring zone, and an X-direction movable plate which movably supports said Y-direction movable plate for movement in the Y-direction, said X-direction movable plate is movable in an X-direction perpendicular to the Y-direction, a driving force transmitting means for driving said X-direction movable plate and said Y-direction movable plate, and a position varying track ball which rotates to transmit the driving force to said X-direction movable plate and said Y-direction movable plate. 
     
     
       8. An object distance measuring device according to claim 7, wherein said measuring zone includes a zone mark which is provided on said Y-direction movable plate. 
     
     
       9. An object distance measuring device according to claim 1, wherein said object distance measuring unit driving means comprises a position detecting means for detecting the position of said measuring zone, an arithmetic operating means for calculating the angular displacement of said object distance measuring unit necessary for following said measuring zone in accordance with the detected data of said position detecting means, and a driving means for driving said object distance measuring unit in accordance with the result of the arithmetic operation of said arithmetic operating means. 
     
     
       10. An object distance measuring device according to claim 9, wherein said position detecting means comprises an X-direction detecting means and a Y-direction detecting means which detect said measuring displacement of the zone in the X-direction and said Y-direction, respectively. 
     
     
       11. An object distance measuring device according to claim 10, further comprising a finder lens. 
     
     
       12. An object distance measuring device according to claim 11, wherein said X-direction detecting means comprises a code plate having codes in accordance with the deviation of an X-direction movable plate in an X-direction from said .[.;.]. optical axis of the finder lens and a position detecting brush which comes into contact with said code plate to detect the deviation in the X-direction. 
     
     
       13. An object distance measuring device according to claim 11, wherein said Y-direction detecting means comprises a code plate having codes in accordance with the deviation of .[.an.]. .Iadd. a .Iaddend.Y-direction movable plate in the Y-direction from said .[.and.]. optical axis of the finder lens and a position detecting brush which comes into contact with .[.the.]. .Iadd.said .Iaddend.code plate to detect the deviation in the Y-direction. 
     
     
       14. In an object distance measuring device in a camera, including an active object distance measuring means for emitting measuring light toward an object to be photographed and receiving the measuring light as reflected by the object to detect the object distance, and a measuring zone provided in a finder to indicate a measuring position at which the measurement of the object distance by said active object distance measuring means is effected, said device comprising: means for varying the position of said measuring zone in said finder;   means for varying the position measured by said active object distance measuring means; and   means for coinciding said measuring zone in said finder and the measuring position of said active object distance measuring means.