| 摘要 |
PURPOSE:To specify the optimum position of a lens from the lens position when the lens is moved along the optical axis within the plane corresponding to an original face and respective charts are projected on sensors disposed in prescribed positions. CONSTITUTION:The sensors 51, 52 are disposed in the positions conjugate with the adequate position of the zoom lens 25 within the plane corresponding to the original face. An arithmetic control part 60 moves the zoom lens 25 by stepping a motor 61 and stops the lens when the sensor 51 captures the image of the chart 41. The lens position L1(X3, Y3) is specified by the output of a detector 62 and a coordinate X3 is computed. The lens position L2(X4, Y4) when the chart image 42 is projected onto the sensor 52 is similarly specified by the detector 62 and a coordinate X4 is computed. A central value L3(X5, Y5) is in succession computed from X5=(X3+X4)/2 and the motor 61 is stepped. The arrival at a mid-point L3 is detected by the detector 62 and the control part 60 stops the motor 61. The error of the lens position is corrected by this constitution. |
