Controlling the perceived depth of autostereoscopic display device and method therefor

1. An autostereoscopic display device comprising:

a display panel having an array of display pixels for producing a display, the pixels being arranged in rows and columns; and

at least two arrays of light output directing elements, the arrays being arranged in series over the display panel at different depths, each array being controllable to direct the light output from respective groups of pixels in different directions to enable a stereoscopic image to be perceived,

wherein the device selectively controls any one of the arrays to provide the light output directing function, thereby providing respective first and second three dimensional display modes having different amounts of perceived depth, and

wherein the display panel is driven with display data in a format that depends on which of the arrays is being selectively controlled to provide the light output directing function.

2. The autostereoscopic display device according to claim 1 , wherein each array of light output directing elements comprises an electro-optic material, the array being controllable to provide the light output directing function by applying an electrical potential to the electro-optic material to alter its refractive index.

3. The autostereoscopic display device according to claim 2 , wherein each array of light output directing elements comprises an array of parallel lenticular elements formed of the electro-optic material.

4. The autostereoscopic display device according to claim 3 , wherein lenticular elements of respective different arrays are parallel to each other.

5. The autostereoscopic display device according to claim 3 , wherein lenticular elements of respective different arrays are not parallel to each other.

6. The autostereoscopic display device according to claim 4 , wherein a ratio of the lenticular element pitches of the arrays is equal to a ratio of the separations of the arrays from the display panel.

7. The autostereoscopic display device according to claim 2 , wherein the electro-optic material comprises a liquid crystal material.

8. The autostereoscopic display device according to claim 2 , wherein the electro-optic material is disposed between transparent electrodes, the electrodes being for applying the electric potential to the electro-optic material.

9. The autostereoscopic display device according to claim 1 , wherein the device further controls the arrays so that neither provides the light output directing function, thereby providing a two dimensional display mode.

10. The autostereoscopic display device according to claim 1 , comprising more than two arrays of light output directing elements, the device providing a corresponding number of three dimensional display modes.

11. The autostereoscopic display device according to claim 1 , wherein the display pixels have a rectangular shape, the longer edges of the display pixels extending in the column direction.

12. The autostereoscopic display device according to claim 1 , wherein the rows and columns of display pixels are orthogonal.

13. The autostereoscopic display device according to claim 1 , wherein the display panel is a liquid crystal display panel.

14. The autostereoscopic display device according to claim 1 , wherein a display pixel is provided at every intersection of the display pixel rows and columns.

15. A method of operating a display device to provide an autostereoscopic display, the display device comprising a display panel having an array of display pixels, and first and second arrays of light output directing elements arranged in series over the display panel at different depths, the method comprising:

selecting one of first and second three dimensional display modes, the display modes each providing different amounts of perceived depth;

controlling a respective one of the arrays of light output directing elements to direct the light output from respective groups of pixels in different directions to enable a stereoscopic image to be perceived, the other of the arrays being controlled not to provide a light output directing function, and

driving the display panel with display data in a format that depends on which of the arrays is being controlled to provide the light output directing function.

16. The method according to claim 15 , wherein each array of light output directing elements comprises an electro-optic material, the array being controllable to provide the light output directing function by applying an electrical potential to the electro-optic material to alter its refractive index.

17. The method according to claim 16 , wherein the electro-optic material comprises a liquid crystal material.