Patent ID: 8830210
Filing Date: 2014-09-09
Classification: G02B,G06F

Abstract:
1. An optical touch apparatus, comprising: a plurality of light emitting devices comprising a first light emitting device, a second light emitting device, a third light emitting device, and a fourth light emitting device respectively disposed beside a display area and capable of respectively emitting a first beam, a second beam, a third beam, and a fourth beam; a first image detector disposed beside the display area; a second image detector disposed beside the display area; a first light guiding unit disposed beside the display area, located within a detecting range of the second image detector, and located in a transmission path of the first beam; a second light guiding unit disposed beside the display area, located within a detecting range of the first image detector and a detecting range of the second image detector, and located in transmission paths of the second beam and the third beam, wherein the second light emitting device and the third light emitting device are respectively located at two opposite sides of the second light guiding unit; a third light guiding unit disposed beside the display area, located within the detecting range of the first image detector, and located in a transmission path of the fourth beam, wherein the second light emitting device is nearer to the first light guiding unit than the third light emitting device is, and the third light emitting device is nearer to the third light guiding unit than the second light emitting device is; and a control unit electrically connected to the first light emitting device, the second light emitting device, the third light emitting device, the fourth light emitting device, the first image detector, and the second image detector, wherein the control unit controls an average brightness of the second light emitting device, an average brightness of the third light emitting device, and an average brightness of the fourth light emitting device respectively to be a first average brightness, a second average brightness, and a third average brightness when the control unit controls the first image detector to detect a first image, the second average brightness of the third light emitting device is less than the first average brightness of the second light emitting device, and the second average brightness of the third light emitting device is less than the third average brightness of the fourth light emitting device, and the control unit controls the average brightness of the first light emitting device, the average brightness of the second light emitting device, and the average brightness of the third light emitting device respectively to be a fourth average brightness, a fifth average brightness, and a sixth average brightness when the control unit controls the second image detector to detect a second image, and the fifth average brightness of the second light emitting device is less than the fourth average brightness of the first light emitting device, and the fifth average brightness of the second light emitting device is less than the sixth average brightness of the third light emitting device, wherein the second average brightness is less than the sixth average brightness, and the fifth average brightness is less than the first average brightness.