Optical touchpad for touch and gesture recognition

摘要

An optical touchpad including a prism having a four-sided cross section including a light entry interface, a light exit interface, a touch interface and a back interface substantially parallel to and spaced apart from the touch interface. Collimated light enters the prism through the light entry interface, is reflected from the touch interface by total internal reflection, and exits the prism through the light exit interface. A first image sensor detects the collimated light exiting from the light exit interface and a second image sensor detects the image of an object positioned over the touch interface.

主权项

1. An optical touchpad comprising:
a prism having a four-sided cross section including a light entry interface, a light exit interface, a touch interface and a back interface substantially parallel to and spaced apart from the touch interface; a source of collimated light, wherein the collimated light enters the prism through the light entry interface, is reflected from the touch interface by total internal reflection, and exits the prism through the light exit interface, and wherein the source of collimated light emits light in a first wavelength range; a first image sensor for detecting the collimated light exiting from the light exit interface; a lens for forming an image of a hand positioned above the touch interface through the touch interface and the back interface, wherein the hand forms a gesture but does not touch the touch interface, wherein the hand is illuminated by an imaging light source different than the source of collimated light, and wherein the imaging light source emits light in a second wavelength range; a second image sensor comprising a two-dimensional array of light-sensitive elements and optically coupled to the lens wherein the second image sensor can capture a two-dimensional image of the hand; and a processor coupled to the second image sensor, wherein the processor can read the two-dimensional image of the hand and process the two-dimensional image to identify the gesture; a first filter disposed between the light exit interface and the first image sensor, wherein the first filter passes the first wavelength range; and a second filter disposed between the prism and the second image sensor, wherein the second filter passes the second wavelength range.