PICTURE INPUT/OUTPUT DEVICE AND PROJECTION DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To simplify the operation which is performed in focusing a projection lens. SOLUTION: Operation signals from a NEAR switch 421 and a FAR switch 422 are inputted to a control part 40. The control part 40 issues a command to a processing part 30 and an OSD memory 36 to output to a driving circuit 32 a signal for projecting a cross marker for focusing. The driving circuit 32 outputs a driving signal to an optical system 33 so that the picture of the cross marker is projected on a screen. The optical system 33 drives liquid crystal panels P1 to P3 (Figure 3) for respective RGB colors to project the cross marker picture onto the screen from a projection lens 6.