Patent ID: 7463391

Claim:
An image sensor comprising: a sensing substrate with image sensing elements disposed thereon; a light source adapted for illuminating the object to be scanned; a lens for gathering the light reflected from the object to be scanned and focusing the reflected light on the image sensing elements on the sensing substrate; a housing for housing the sensing substrate, the light source and the lens; and a focus adjusting device disposed in the housing, the focus adjusting device comprising a focus adjusting element movable in a first direction relative to the housing, and a contact element for directly contacting with a lower surface of a scanner cover plate where the object to be scanned rests, the contact element being movable in the first direction when driven by the focus adjusting element; wherein when the contact element is driven to move in the first direction by the focus adjusting element, the distance between an upper surface of the housing and the lower surface of the scanner cover plate is correspondingly changed; and wherein the focus adjusting device further comprises a focus varying element disposed between the contact element and the focus adjusting element, the focus varying element directly engaging with the contact element in the first direction and being independently movable in a second direction perpendicular to the first direction for driving the contact element to also move in the first direction.