Optical fingerprint navigation device with light guide film
Embodiments of a finger navigation device are described. In one embodiment, the finger navigation device includes a light guide film (LGF), a light source, a sensor, and a navigation engine. At least a portion of the LGF exhibits total internal reflection (TIR) and the light source is in optical communication with the LGF and configured to inject light into the LGF. The sensor is configured to detect light that exits from the LGF after being reflected from a finger that is proximate the LGF and the navigation engine is configured to generate lateral movement information, which is indicative of lateral movement of the finger relative to the sensor, in response to light that is reflected from the finger and detected by the sensor. Other embodiments of the finger navigation device are also described.
1. An optical finger navigation device comprising:
a light guide film (LGF), wherein at least a portion of the LGF exhibits total internal reflection (TIR);
a light source in optical communication with the LGF and configured to inject light into the LGF;
a sensor configured to detect light that exits from the LGF after being reflected from a finger that is proximate the LGF; and
a navigation engine configured to generate lateral movement information, which is indicative of lateral movement of the finger relative to the sensor, in response to light that is reflected from the finger and detected by the sensor;
wherein the LGF is between 10 microns and 100 microns thick; and
further comprising a circuit board substrate, wherein the light source, the sensor, and the navigation engine are attached to the circuit board substrate and wherein the LGF is laminated directly to the circuit board substrate with no intervening optical lenses between the circuit board substrate and the LGF.
2. The optical finger navigation device of claim 1 , wherein the LGF comprises a major surface and a side edge and wherein the light source is configured to inject light into the LGF at the side edge.
3. The optical navigation device of claim 2 , wherein the LGF is configured with a hole that corresponds to the location of the light source, wherein the major surface of the LGF is parallel to a major surface of the circuit board substrate.
4. The optical navigation device of claim 3 , wherein the hole in the LGF is formed by an edge of the LGF that is perpendicular to the major surface of the LFG.
5. The optical navigation device of claim 3 , wherein the hole is filled with a transparent epoxy.
6. The optical finger navigation device of claim 1 , wherein the LGF comprises a plurality of light extracting features that cause light to exit the LGF through a surface that is opposite the sensor.
7. The optical finger navigation device of claim 6 , wherein the plurality of light extracting features comprise a plurality of recessions at a major surface of the LGF.
8. The optical finger navigation device of claim 6 , wherein the plurality of light extracting features are formed within the LGF.
9. The optical finger navigation device of claim 1 , wherein the LGF comprises a major surface with a planar portion and a plurality of non-planar elements at least partially out of plane with the planar portion, wherein the non-planar elements cause light to exit the LGF.
10. The optical finger navigation device of claim 9 , wherein the non-planar elements comprise a plurality of light extracting features that are recessed below the major surface of the LGF.
11. The optical finger navigation device of claim 9 , wherein the plurality of light extracting features comprises an array of recessions with cylindrical chamfers.
12. The optical finger navigation device of claim 9 , wherein the plurality of non-planar elements are shaped to emphasize specular highlights and shadows in the finger.
13. An optical finger navigation device comprising:
a circuit board substrate;
a sensor attached to the circuit board substrate, the sensor including an array of distinct photodetectors;
a light guide film (LGF) of between 10 microns and 100 microns thick that is attached directly to the circuit board substrate with no optical lenses between the circuit board substrate and the LGF and located proximate the sensor such that the sensor is between the circuit board and at least a portion of the LGF with no optical lenses between the sensor and the LGF;
a light source attached to the circuit board substrate and configured to inject light into an edge surface of the LGF; and
a navigation engine configured to generate movement information, which is indicative of movement of a finger relative to the sensor, in response to light that is reflected from the finger and detected by the sensor.
14. The optical finger navigation device of claim 13 , wherein the LGF is laminated directly to the circuit board substrate with a glue that has a lower index of refraction than the LGF.
15. The optical finger navigation device of claim 13 , wherein the LGF comprises a plurality of light extracting features.
16. A portable hand-held electronic system comprising:
a display comprising a navigation indicator;
an optical finger navigation device configured to generate a navigation signal to move the navigation indicator based on a change in a detected light pattern according to movement of a finger relative to the optical finger navigation device, the optical finger navigation device comprising;
a circuit board;
a light guide film (LGF) of between 10 microns and 100 microns thick, wherein at least a portion of the LGF exhibits total internal reflection (TIR) and wherein the LGF is laminated directly to the circuit board substrate with no optical lenses between the circuit board substrate and the LGF;
a light source attached to the circuit board substrate and in optical communication with the LGF and configured to inject light into the LGF;
a sensor attached to the circuit board substrate and configured to detect light that exits from the LGF after the light is reflected from the finger; and
a navigation engine configured to generate lateral movement information, which is indicative of lateral movement of the finger relative to the sensor, in response to light that is reflected by the finger and detected by the sensor.
17. The portable hand-held electronic system of claim 16 , wherein the LGF comprises a plurality of light extracting features that cause light to exit the LGF.
18. The portable hand-held electronic system of claim 16 , wherein the LGF comprises a major surface and wherein the plurality of light extracting features comprise a plurality of recessions in the LGF at the major surface.
19. The portable hand-held electronic system of claim 16 , wherein the LGF comprises a major surface and a side edge and wherein the light source is configured to inject light into the LGF at the side edge.
20. The portable hand-held electronic system of claim 16 , wherein the LGF comprises a major surface and a side edge that forms a hole completely through the LFG and wherein the light source is located within the hole in the LGF such that light is injected into the LGF at the side edge the LGF and wherein void space in the hole is filled with a transparent epoxy.