Variable iris using charged opaque particles

Abstract

Variable iris using charged opaque particles The present invention relates to a variable iris using charged opaque particles, and to a method for operating such a variable iris.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding the invention shall now be explained in more detail in the following description with reference to the Figures. It is understood that the invention is not limited to this exemplary embodiment and that specified features can also expediently be combined and/or modified without departing from the scope of the present invention. In the Figures:

FIG. 1 depicts a side view and a top view of a variable iris according to the invention in an open stated,

FIG. 2 shows the variable iris in a partially closed state,

FIG. 3 depicts a variable iris with four ring-shaped electrodes,

FIG. 4 shows a variable iris with an electrode located on a rib,

FIG. 5 depicts a variable iris using a rib as an electrode,

FIG. 6 shows a variable iris using both positively and negatively charged particles,

FIG. 7 depicts a variable iris having dielectric layers on the electrodes,

FIG. 8 shows the pulsed operation of a variable iris with three electrodes,

FIG. 9 depicts the pulsed operation of a variable iris with four electrodes,

FIG. 10 illustrates the pulsed operation of a variable iris with five electrodes, and

FIG. 11 shows the pulsed operation of a variable iris with seven electrodes.

Claims

1. Variable iris having a first transparent substrate and a second transparent substrate, which are separated by one or more ribs to form a cell confining charged opaque particles, the first transparent substrate being provided with at least a first electrode and a second electrode both being adapted to be connected to a voltage source for acting on the charged opaque particles, and at least a third electrode adapted to be connected to the voltage source for acting on the charged opaque particles, the voltages applied to the first electrode, the second electrode, and the third electrode being controllable to have the same or opposite signs, wherein it includes a pulse driver for applying voltage pulses to the electrodes.

2. Variable iris according to claim 1, wherein the third electrode is located on the second transparent substrate or on the ribs.

3. Variable iris according to claim 1, wherein the ribs form the third electrode.

4. Variable iris according to claim 1, wherein both positively and negatively charged opaque particles are confined in the cell.

5. Variable iris according to claim 1, wherein at least one of the first transparent substrate and the second transparent substrate is covered with a dielectric layer.

6. Method for operating a variable iris having a first transparent substrate and a second transparent substrate, which are separated by one or more ribs to form a cell confining charged opaque particles of a first sign, the first transparent substrate being provided with at least a first electrode and a second electrode both being adapted to be connected to a voltage source for acting on the charged opaque particles, and at least a third electrode adapted to be connected to the voltage source for acting on the charged opaque particles, having the steps of: applying a voltage of the first sign to the second electrode and the first electrode;applying a voltage pulse of an opposite sign to the third electrode,applying a voltage of the opposite sign to either the first electrode or the third electrode.

7. Method according to claim 6, further having the step of subsequently applying voltage pulses of the opposite sign to further intermediate electrodes between the first electrode and the second electrode.

8. Apparatus for reading from and/or writing to optical recording media, wherein that it includes a variable iris according to claim 1.

9. Imaging apparatus, wherein that it includes a variable iris according to of claim 1.

10. Projection apparatus, wherein that it includes a variable iris according to of claim 1.

11. Apparatus for reading from and/or writing to optical recording media, wherein that it includes a variable iris according to claim 2.

12. Apparatus for reading from and/or writing to optical recording media, wherein that it includes a variable iris according to claim 3.

13. Apparatus for reading from and/or writing to optical recording media, wherein that it includes a variable iris according to claim 4.

14. Apparatus for reading from and/or writing to optical recording media, wherein that it includes a variable iris according to claim 5.

15. Imaging apparatus, wherein that it includes a variable iris according to claim 2.

16. Imaging apparatus, wherein that it includes a variable iris according to claim 3.

17. Imaging apparatus, wherein that it includes a variable iris according to claim 4.

18. Imaging apparatus, wherein that it includes a variable iris according to claim 5.

19. Projection apparatus, wherein that it includes a variable iris according to claim 2.

20. Projection apparatus, wherein that it includes a variable iris according to claim 3.

21. Projection apparatus, wherein that it includes a variable iris according to claim 4.

22. Projection apparatus, wherein that it includes a variable iris according to claim 5.