Optical fingerprint navigation device with light guide film

Abstract

An optical finger navigation device. Embodiments of the optical finger navigation device include a light guide film (LGF) including a finger interface surface, a light source in optical communication with the LGF to provide light from the light source to the finger interface surface, a sensor, and a navigation engine. At least a portion of the LGF exhibits total internal reflection (TIR). The sensor detects light from the LGF in response to contact between a finger and the finger interface surface which modifies reflection of light out of the LGF to the sensor. The light detected by the sensor is changed over at least a portion of the sensor in response to the contact between the finger and the finger interface surface. The navigation engine is configured to generate lateral movement information indicative of lateral movement of the finger relative to the sensor, in response to the detected light.

What is claimed is: 
     
         1 . A method of manufacture for an optical finger navigation device comprising:
 forming a plurality of non-planar elements on a finger interface surface of a light guide film (LGF), wherein the non-planar elements at least partially protrude beyond a substantially planar major surface of the LGF, wherein at least a portion of the LGF exhibits total internal reflection (TIR);   coupling the LGF to a sensor configured to detect a change in a pattern of light from the LGF in response to contact between a finger and the finger interface surface, wherein the contact between the finger and the finger interface surface modifies the TIR, to allow a portion of the light from the LGF over at least a portion of the finger interface surface to escape from the LGF, interact with the finger, and modify a pattern of light reaching the sensor; and   coupling a light source in optical communication with the LGF to provide light from the light source to the finger interface surface.   
     
     
         2 . The method of  claim 1 , wherein the non-planar elements are formed by a spraying process. 
     
     
         3 . The method of  claim 1 , wherein the non-planar elements are formed by a printing process. 
     
     
         4 . The method of  claim 1 , wherein the non-planar elements are formed by a molding process. 
     
     
         5 . The method of  claim 1 , further comprising a spacer disposed between the LGF and the sensor, wherein the spacer supports the LGF at approximately a fixed distance from the sensor. 
     
     
         6 . The method of  claim 5 , wherein the spacer comprises at least one spherical element.