Light sensitive display

1. A display device having a surface for viewing an image comprising:

a stack of layers configured to display the image; and

a plurality of light sensitive elements included in the stack, the plurality of light sensitive elements configured to detect an object on or near the surface,

wherein a processor is configured to detect a touching state of the object based on a region having an inner region and an outer region,

wherein the touching state is detected when the inner region is lighter than the outer region and lighter than ambient light reaching the display, and the outer region is darker than the inner region and darker than ambient light reaching the display,

a light guide having a surface wherein the processor is configured to detect the touching state of the object relative to the surface of the light guide,

wherein the plurality of light sensitive elements are configured to detect a diffusion of light from the light guide due to contact of the object on the light guide.

2. The display device as recited in claim 1 wherein the processor is configured to detect a hover state of the object when the inner region and the outer region are darker than ambient light reaching the display.

3. The display device as recited in claim 1 wherein the processor is configured to detect a location of the inner region based on a center of gravity technique.

4. The display device as recited in claim 1 wherein the processor is configured to distinguish between the touching state and a hover state based on detecting when the inner region is lighter than the outer region.

5. The display device as recited in claim 1 wherein the object has an index of refraction within a range of 0.5 to 0.25 of an index of refraction of the light guide.

6. The display device as recited in claim 1 wherein the object is one of a stylus and a finger.

7. A display device having a surface for viewing an image comprising:

a stack of layers configured to display the image; and

a plurality of light sensitive elements included in the stack, the plurality of light sensitive elements configured to detect an object on or near the surface,

wherein a processor is configured to distinguish between a touching state of the object and a hover state of the object by

determining that the object is in the touching state relative to the display device based on detecting a region having an inner region and an outer region, wherein the touching state is detected when the inner region is lighter than the outer region and lighter than ambient light reaching the display, and the outer region is darker than the inner region and darker than ambient light reaching the display; and

determining that the object is in the hover state relative to the display device based on detecting the region, wherein the hover state is detected when the inner region and the outer region are darker than ambient light reaching the display,

a light guide having a surface wherein the processor is configured to detect the touching state of the object relative to the surface of the light guide

wherein the plurality of light sensitive elements are configured to detect a diffusion of light from the light guide due to the touching state of the object on the light guide.

8. The display device as recited in claim 7 wherein the processor is configured to detect the inner region based on a center of gravity technique.

9. The display device as recited in claim 7 wherein the object has an index of refraction within a range of 0.5 to 0.25 of an index of refraction of the light guide.

10. The display device as recited in claim 7 wherein the object is one of a stylus and a finger.

11. The display device as recited in claim 7 further comprising a light source providing light to the light guide, wherein the light source is configured to switch between providing the light comprising a range of wavelengths less than white light and providing a light corresponding to white light.

12. The display device as recited in claim 7 further comprising a light source providing light to the light guide, wherein the light source is configured to switch between the light source providing a first light comprising a first range of wavelengths and providing a second light comprising a second range of wavelengths.

13. The display device as recited in claim 11 wherein the light source is configured to switch in response to a state of a switch on the device.

14. The display device as recited in claim 12 wherein the light source is configured to switch in response to a state of a switch on the device.