Device comprising a stack of individual liquid crystal cells having electrical circuitry operable to generate a stack of refractive index patterns and method of producing the same

1. A method, comprising: producing at least first and second individual liquid crystal cells, wherein the first and second individual liquid crystal cells each comprise liquid crystal material between a respective pair of support components, and electrical circuitry operable to generate a refractive index pattern in the liquid crystal material; the method comprising adhering together at least the first and second liquid crystal cells to form a stack of liquid crystal cells; wherein the electrical circuitry of the first and second liquid crystal cells is operable together to generate a stack of refractive index patterns in the liquid crystal material of the stack of liquid crystal cells;

wherein the method comprises: producing the first cell by a process comprising pressing first and second half-cells together between first and second carriers temporarily adhered to the first and second half-cells, and thereafter releasing the first cell from the first carrier while keeping the first cell temporarily adhered to the second carrier; producing the second cell by a process comprising pressing third and fourth half-cells together between third and fourth carriers temporarily adhered to the third and fourth half-cells, and thereafter releasing the second cell from the third carrier while keeping the second cell temporarily adhered to the fourth carrier; and thereafter pressing the first and second cells together via the second and fourth carriers.

2. The method according to claim 1 , wherein the electrical circuitry of at least first and second liquid crystal cells comprise coincident electrode patterns in the stack of liquid crystal cells, such that a common electrical input generates a stack of coincident refractive index patterns in at least the first and second liquid crystal cells.

3. The method according to claim 1 , wherein the electrical circuitry of the first and second liquid crystal cells of the stack of liquid crystal cells comprises substantially matching first and second electrode patterns, wherein a centre axis of the first electrode pattern is aligned with a centre axis of the second electrode pattern, and the first electrode pattern is rotated relative to the second electrode pattern about the centre axis.

4. The method according to claim 1 , wherein the support components comprise plastics support film components.

5. The method according to claim 4 , wherein the plastics support film component comprises a plastics support film; and wherein the electrical circuitry of the first and second liquid crystal cells is connected in parallel to a common input contact or set of input contacts via holes through the plastics support films.

6. The method according to claim 1 , wherein the electrical circuitry comprises a set of concentric conductors.

7. The method according to claim 6 , wherein the electrical circuitry further comprises a set of addressing conductors below the set of concentric conductors, wherein each concentric conductor is in contact with a respective one of the addressing conductors through a respective via-hole in one more insulating layers between the set of concentric conductors and the set of addressing conductors.

8. The method according to claim 6 , wherein the concentric conductors are connected in series to a common input contact.

9. The method according to claim 8 , wherein adjacent concentric conductors are connected in series via one or more relatively low conductance elements, or adjacent concentric conductors are connected in series via one or more variable resistance elements, wherein the resistance of each variable resistance element is controllable via one or more input contacts.

10. The method according to claim 9 , wherein the variable resistance elements comprise semiconductor channels capacitively coupled to addressable gate conductors.

11. The method according to claim 6 , wherein the concentric conductors comprise a set of elliptical conductors or a set of circular conductors.

12. The method according to claim 1 , wherein the electrical circuitry comprises an array of pixel electrodes each independently controllable via a respective addressing conductor.

13. A device, comprising: a stack of at least first and second liquid crystal cells, each of the first and second liquid crystal cells comprising liquid crystal material, and electrical circuitry operable to generate a refractive index pattern in the liquid crystal material; wherein the electrical circuitry of the first and second liquid crystal cells is interconnected such that a common electrical input generates a stack of refractive index patterns in the liquid crystal material of the stack of first and second liquid crystal cells; wherein the electrical circuitry comprises a set of concentric conductors;

wherein the concentric conductors of a liquid crystal cell are connected in series to a common input contact.

14. The device according to claim 13 , wherein adjacent concentric conductors are connected in series via one or more relatively low conductance elements, or are connected in series via one or more variable resistance elements, wherein the resistance of each variable resistance element is controllable via one or more input contacts, or the variable resistance elements comprise semiconductor channels capacitively coupled to addressable gate conductors.

15. The device according to claim 13 , wherein the concentric conductors comprise a set of elliptical conductors or a set of circular conductors.

16. A method comprising:

producing at least first and second individual liquid crystal cells, wherein the first and second individual liquid crystal cells each comprise liquid crystal material between a respective pair of support components, and electrical circuitry operable to generate a refractive index pattern in the liquid crystal material; and

adhering together at least the first and second liquid crystal cells to form a stack of liquid crystal cells,

wherein the electrical circuitry of the first and second liquid crystal cells comprises a set of concentric conductors connected in series to a common input contact, the electrical circuitry being operable together to generate a stack of refractive index patterns in the liquid crystal material of the stack of liquid crystal cells.

17. The method according to claim 16 , wherein adjacent concentric conductors are connected in series via one or more relatively low conductance elements, or adjacent concentric conductors are connected in series via one or more variable resistance elements, wherein the resistance of each variable resistance element is controllable via one or more input contacts.

18. The method according to claim 17 , wherein the variable resistance elements comprise semiconductor channels capacitively coupled to addressable gate conductors.

19. The method according to claim 16 , wherein the concentric conductors comprise a set of elliptical conductors or a set of circular conductors.