Patent ID: 8451252

Claim:
An image sensor for a touch screen, which is installed at an edge of the touch screen and comprising a single image sensing element and an optical imaging system, the optical imaging system having at least two optical paths comprising two separated lenses installed at the edge of the touch screen, a first reflection mirror and a reflection/transmission mirror; wherein each of the lenses includes a concavo-convex lens, an objective lens of each of the lenses is faced to the touch screen, an overlapping area of fields of view of the objective lenses covers the touch screen; wherein one of the two lenses, the first reflection mirror and the reflection/transmission mirror forms a first optical path, and the other of the two lenses and the reflection/transmission mirror forms a second optical path; wherein a reflection surface of the first reflection mirror is opposite to a reflection surface of the reflection/transmission mirror which is towards the image sensing element; wherein light emitted from the lens on the first optical path reaches a surface of the image sensing element through the first reflection mirror and the reflection surface of the reflection/transmission mirror; wherein light emitted from the lens on the second optical path reaches the surface of the image sensing element through a transmission surface of the reflection/transmission mirror; and wherein a touch object on the touch screen is imaged by each of the first and second optical paths in the optical imaging system, and the formed images are projected on the image sensing element.