| 摘要 |
PROBLEM TO BE SOLVED: To easily and accurately detect the position of an observer by constituting a position detecting part of a light-emitting part, a lens part and a sensor part receiving reflected light. SOLUTION: When the head part 16 to of the observer existing at a position opposed to the screen center of a display part on an appropriate visual distance D is moved right and left and is deviated from the area A1 of a first lightentering state opposed to the screen center and the light or left end of the head part 16 enters either of the right and left areas B1R and B1L, a part of the light emitted from the light-emitting part 17 and image formed by first and second lens parts 18a and 18b is reflected by the head part 16 and is made incident on either of first and second light-receiving parts 19A and 19b. Thus, it detects that the head part 16 of the observer enters the area B1L (B1R) which is made in a second light-entering state, so that a control circuit outputs a low control signal to a timing signal generating circuit so as to make the state of the display screen of a display in a normal state. |
