Patent ID: 7561119

Claim:
A screen image display apparatus comprising a plurality of display blocks arrayed in a prescribed direction with each of the plurality of display blocks including a plurality of light emitting modules, comprising, for each of the display blocks: a signal supply unit to supply serially the plurality of light emitting modules with a signal so as to let the light emitting modules display a character or image; a signal transfer unit to transfer the signal supplied for one display block to the signal supply unit for the one display block and another of the display unit; wherein the signal supply unit comprises: a first signal supply unit to supply the light emitting module with the signal transferred from one transfer direction, a second signal supply unit to supply the light emitting module with the signal transferred from another transfer direction; and a switching unit to switch between the first and second signal supply units, wherein said switching unit comprises an optical sensor for detecting whether or not there is an obstacle close to the rear surface of said display apparatus, wherein either said first or second signal supply unit is switched on automatically based on a signal detected by the optical sensor.