METHODS OF SWITCHING AND APPARATUS COMPRISING AN ELECTRICALLY ACTUATED VARIABLE TRANSMISSION MATERIAL

• US 20110170030A1
• Filed: 09/22/2009
• Published: 07/14/2011
• Est. Priority Date: 09/22/2008
• Status: Active Grant

• Current Assignee: Pilkington Group Limited
• Original Assignee: Pilkington Group Limited
• Inventors: Boote, Joseph Jeremy
• Granted Patent: US 8,537,295 B2
• Time in Patent Office: Days
• US Class Current: 349/41
• CPC Class Codes: E06B 2009/2464 featuring transparency control by applying voltage, e.g. LCD, electrochromic panels
• CPC Class Codes: E06B 9/24 Screens or other constructions affording protection against light, especially against sunshine; Similar screens for privacy or appearance; Slat blindsoperating, guiding or securing devices or arrangements for roll-type closures E06B9/56; free-hanging flexible screens A47H23/00
• CPC Class Codes: G02F 1/172 based on a suspension of orientable dipolar particles, e.g. suspended particles displays

Abstract

A method of switching an electrically actuated variable transmission layer is disclosed. The layer is between a first electrode and a second electrode, and when a sufficiently high frequency alternating electric field is applied between the first and second electrodes, a selective region of the layer in between the first and second electrodes is switched. Apparatus for use as a glazing pane having a sheet of glazing material and an electrically actuated variable transmission layer facing the sheet of glazing material is also disclosed. The layer is sandwiched between a first electrode and a second electrode. There is an electric field generator in electrical communication with the electrodes and being configured to produce an alternating electric field of sufficient strength and of a sufficiently high frequency to switch a selected region of the layer in between the first and second electrodes.

Claims

1. A method of switching an electrically actuated variable transmission layer, the layer being between a first electrode and a second electrode, wherein a sufficiently high frequency alternating electric field is applied between the first and second electrodes such that a selective region of the layer in between the first and second electrodes is switched.

2. A method according to claim 1, wherein the selectively switched region has graded transmission.

3. A method according to claim 1, wherein the electrically actuated variable transmission layer comprises an SPD film or a liquid crystal containing film.

4. A method according to claim 1, wherein the frequency of the applied electric field is greater than 1 kHz, preferably greater than 10 kHz, more preferably at least 20 kHz.

5. A method according to claim 1, wherein the electric field is applied via a power supply having a variable output voltage.

6. A method according to claim 1, wherein the electric field is applied via a power supply having a variable output frequency.

7. A method according to claim 1, wherein the electric field is applied via a power supply having a variable output waveform.

8. A method according to claim 5, wherein there is a resistor in series with one of the electrodes and the power supply.

9. A method according to claim 1, wherein the applied electric field is a substantially rectangular waveform.

10. A method according to claim 1, wherein the electric field is applied by a direct galvanic connection to the first electrode and/or second electrode.

11. A method according to claim 1, wherein the electric field is applied by at least one remote electrical connection that is remote to the first electrode and second electrode.

12. A method according to claim 10, wherein the electrical field is applied by a plurality of electrical connectors associated with the first and/or second electrode.

13. Apparatus for use as a glazing pane, comprising a sheet of glazing material and an electrically actuated variable transmission layer facing the sheet of glazing material, the layer being sandwiched between a first electrode and a second electrode, and an electric field generator in electrical communication with the electrodes and being configured to produce an alternating electric field of sufficient strength and of a sufficiently high frequency to switch a selected region of the layer in between the first and second electrodes.

14. Apparatus according to claim 13, wherein the layer is laminated between two sheets of glazing material.

15. Apparatus according to claim 13, wherein the selected region has graded transmission.

16. Apparatus according to claim 13, wherein the electric field generator is able to generate an alternating electric field having a frequency greater than 1 kHz, more preferably greater than 10 kHz, even more preferably greater than 20 kHz.

17. Apparatus according to claim 13, wherein there is a resistor, preferably a variable resistor, in series with the electric field generator and one of the electrodes.

18. Apparatus according to claim 13, wherein the electric field generator is in electrical communication with the first and/or second electrode via at least one direct galvanic connection thereto.

19. Apparatus according to claim 13, wherein the electric field generator is in electrical communication with the first and/or second electrode via at least one remote electrical connection that is remote to the first electrode and second electrode.

20. Apparatus according to claim 18, wherein the electrical field generator is in electrical communication with the first and or second electrode via a plurality of electrical connectors.

21. Apparatus according to claim 13, wherein the glazing pane is a vehicle glazing pane, preferably a windscreen or a sunroof, or a window in a building.

22. A vehicle, in particular a car, comprising an apparatus according to claim 13.

23. A building comprising an apparatus according to claim 13.

24. Use of an electrically actuated variable transmission layer to produce a graded transmission region in the layer, by applying an electric field across the layer of sufficient magnitude to switch the layer on and of a sufficiently high frequency to produce the graded transmission region.

25. Use of an SPD film or a liquid crystal film according to claim 24.