Optical scanning control device
An optical scanning control device includes a scanner that scans light emitted from a laser in accordance with an image signal to form an image on a screen; a first optical detector that detects light scanned by the scanner; a second optical detector that detects light scanned by the scanner; and a controller that controls a deflection angle of the scanner based on a time difference between an output of the first optical detector and an output of the second optical detector.
1. An optical scanning control device comprising:
a scanner that scans light emitted from a laser in accordance with an image signal to form an image on a screen;
a first optical detector that detects light scanned by the scanner;
a second optical detector that detects light scanned by the scanner; and
a controller that controls a deflection angle of the scanner based on a time difference between a first output that is output from the first optical detector and a second output that is output from the second optical detector.
2. The optical scanning control device according to claim 1 , wherein the first optical detector and the second optical detector are arranged in a vertical blanking interval excluding a horizontal blanking interval.
3. The optical scanning control device according to claim 2 , wherein a width of the image drawn on the screen expands and contracts depending on a temperature,
wherein the first optical detector and the second optical detector are arranged at positions furthest to each other in a direction of the width of the image within a range in which the deflection angle of the scanner corresponding to an expected minimum width of the image can be detected.
4. The optical scanning control device according to claim 3 , wherein, when the width of the image drawn on the screen at a predetermined temperature is assumed to be 100, the first optical detector and the second optical detector are arranged at positions corresponding to 44 on left and right from a center of the image.
5. The optical scanning control device according to claim 1 , further comprising:
a plurality of the lasers,
wherein the controller causes one of the plurality of the lasers to emit light so as to measure the time difference.
6. The optical scanning control device according to claim 1 , wherein the controller converts the time difference into the deflection angle of the scanner, and the controller controls the deflection angle of the scanner, so that the converted deflection angle matches an expected deflection angle.
7. The optical scanning control device according to claim 1 , further comprising:
an optical unit on an optical path between the scanner and the screen,
wherein the first optical detector and the second optical detector detect light prior to entering the optical unit.