Method and device for controlling voltage provided to a suspended particle device

• US 20040165251A1
• Filed: 02/13/2003
• Published: 08/26/2004
• Est. Priority Date: 02/13/2003
• Status: Active Grant

• Current Assignee: Research Frontiers Incorporated
• Original Assignee: Research Frontiers Incorporated
• Inventors: Harary, Joseph M., Saxe, Robert L., Malvino, Albert P.
• Granted Patent: US 6,804,040 B2
• Time in Patent Office: Days
• US Class Current: 359/296
• CPC Class Codes: G02B 26/004 based on a displacement or a deformation of a fluid
• CPC Class Codes: G02F 1/172 based on a suspension of orientable dipolar particles, e.g. suspended particles displays

Abstract

A voltage controlling device includes an AC terminal receiving an AC voltage signal, a voltage dividing device adapted to divide the AC voltage signal into a plurality of distinct voltage signals within a predetermined range, a controller adapted to control the voltage dividing device to provide a selected voltage level based on voltage level information and an SPD terminal for providing the selected voltage level to a suspended particle device. An input device may be provided to allow a user to input the voltage level information. A photocell that monitors a light level at the suspended particle device may provide light level information as the voltage level information. A separate AC power supply may also be provided. The controller may also monitor an SPD load voltage to control the selected voltage level provided to the SPD terminal and the suspended particle device in order to prevent shocking of a user.

Claims

1. A voltage controlling device for controlling voltage provided to at least one suspended particle device (SPD) which comprises:

an AC terminal adapted to receive an AC voltage at a specific frequency;

a voltage dividing device adapted to divide the AC voltage into a plurality of distinct voltage values within a predetermine range;

a controller adapted to control the voltage dividing device to provide a selected voltage value based on voltage level information; and

an SPD terminal adapted to provide the selected voltage value to the SPD device.

2. The voltage controlling device of claim 1, wherein the voltage dividing device further comprises:

a capacitor array including a plurality of capacitors where each capacitor in the capacitor array has a predetermined capacitance; and

a switch array, connecting each capacitor of the capacitor array to the SPD terminal such that each switch of the switch array connects one capacitor of the capacitor array to the SPD terminal, wherein

the controller controls the switches of the switch array to connect at least one of the capacitors of the capacitor array to the SPD terminal based on the voltage level information.

3. The voltage controlling device of claim 2, wherein the capacitor array includes 8 capacitors, and the switch array includes 8 switches, respectively connecting each of the eight capacitors to the SPD terminal, such that the voltage dividing device is capable of providing a total of 256 different voltages to the SPD terminal.

4. The voltage controlling device of claim 1, wherein the predetermined range of distinct voltages provided by the voltage dividing device is sufficiently large to provide a maximum voltage to the SPD terminal sufficient to operate a suspended particle device of a corresponding size.

5. The voltage controlling device of claim 1, further comprising an input device adapted to provide the voltage level information from a user of the voltage controlling device.

6. The voltage controlling device of claim 1, wherein the controller monitors an SPD voltage provided to the SPD terminal and controls the voltage dividing device to provide zero voltage to the SPD terminal after the SPD voltage drops a predetermined amount below a predetermined level.

7. The voltage controlling device of claim 1, further comprising an alarm, wherein the controller provides an alarm signal that activates the alarm after the SPD voltage exceeds a predetermined level by a predetermined amount.

8. The voltage controlling device of claim 7, wherein the predetermined level is based on an average value of the SPD voltage over a predetermined period of time.

9. The voltage controlling device of claim 5, wherein the predetermined level is stored in a memory of the controller.

10. The voltage controlling device of claim 1, further comprising a photo detector adapted to monitor a level of light at the suspended particle device, wherein the level of light at the suspended particle device is used as the voltage level information utilized by the controller.

11. The voltage controlling device of claim 1 further comprising:

an AC power supply providing an AC voltage at a low frequency to the AC terminal.

12. The voltage controlling device of claim 11, wherein the AC power supply provides an AC voltage with a frequency of at least 15 hertz.

13. The voltage controlling device of claim 11, wherein the AC power supply comprises:

an AC/DC converter converting an AC voltage signal of a predetermine frequency into a DC voltage signal;

a DC motor operated by the DC voltage signal; and

a generator connected to the DC motor to provide the AC voltage signal at the low frequency.

14. The voltage controlling device of claim 11, wherein the AC power supply further comprises:

a plurality of solar cells connected in parallel;

at least one rechargeable battery adapted to provide a DC voltage signal;

a converter, adapted to convert a DC voltage signal of the at least one rechargeable battery into the AC voltage signal with the low frequency;

wherein

the at least one rechargeable battery is recharged by a recharging voltage signal supplied by the plurality of solar cells.

15. The voltage controlling device of claim 14, wherein the AC power supply is mounted in a movable support in which the suspended particle device is mounted, such that the AC power supply moves with the suspended particle device.

16. The voltage controlling device of claim 1, wherein the suspended particle device includes:

a first conducting layer;

a second conducting layer; and

an emulsion including a plurality of suspended particles which align in a predetermined pattern when exposed to an electric field, where the emulsion is positioned between the first conducting layer and the second conducting layer, and wherein

a first conducting bus connecting the first conducting layer to the SPD terminal and a second conducting bus connecting the second conducting layer to the SPD terminal are positioned on one edge of the suspended particle device.

17. The voltage controlling device of claim 16, wherein a length of the one edge of the suspended particle device is less than a length of another edge of the suspended particle device such that the suspended particle device is substantially rectangular in shape.

18. The voltage controlling device of claim 16, wherein a bus length of the first conducting bus and the second conducting bus is less than a length of the one edge of the suspended particle device.

19. A voltage controlling device for controlling voltage provided to at least one suspended particle device which comprises:

an AC terminal adapted to receive an AC voltage at a specific frequency;

an SPD terminal adapted to provide a selected AC voltage value to the suspended particle device

a capacitor array including a plurality of capacitors where each capacitor in the capacitor array has a predetermined capacitance;

a switch array, connecting each capacitor of the capacitor array to the SPD terminal such that each switch of the switch array connects one capacitor of the capacitor array to the SPD terminal; and

a controller adapted to control the switches of the switch array to connect at least one of the capacitors of the capacitor array to the SPD terminal based on voltage level information, such that a plurality of distinct voltage values within a predetermined range are selectively provided to the SPD terminal.

20. A method of controlling voltage provided to a suspended particle device, which method comprises:

receiving an AC voltage signal at a specific frequency;

dividing the AC voltage signal into a plurality of distinct voltage levels within a predetermined range;

controlling the dividing step to provide a selected voltage level of the plurality of distinct voltage levels to an SPD terminal connected to the suspended particle device based on voltage level information.

21. The method of claim 20, wherein the dividing step further comprises:

providing a capacitor array including a plurality of capacitors, each said capacitor having a predetermined capacitance;

connecting each capacitor of the capacitor array to the SPD terminal via a switch of a switch array, wherein a number of switches in the switch array is the same as a number of capacitors in the capacitor array; and

controlling the switch array and the capacitor array such that at least one capacitor of the capacitor array is connected to the suspended particle device to provide the selected voltage level.

22. The method of claim 21, wherein the connection step includes connecting eight capacitors in the capacitor array via eight switches in the switch array to the SPD terminal, such that a total of 256 selected voltage levels are provided to the SPD terminal.

23. The method of claim 20, wherein the predetermined range of distinct voltages is sufficiently large to provide a maximum voltage to the SPD terminal sufficient to operate a suspended particle device of a corresponding size.

24. The method of claim 20, further comprising:

inputting the voltage level information via an input device for use in the controlling step.

25. The method of claim 20 further comprising,

monitoring an SPD voltage level provided to the SPD terminal;

determining a normal SPD voltage level based on an average SPD voltage level over a predetermined period of time; and

comparing the SPD voltage level to the normal SPD voltage level;

wherein

the controlling step includes providing zero voltage to the SPD terminal after the SPD voltage level drops a predetermined amount below the normal SPD voltage level.

26. The method of claim 25, further comprising:

generating an alarm signal to activate an alarm after the SPD voltage exceeds the normal SPD voltage by a predetermined amount.

27. The method of claim 25, wherein the normal SPD voltage level is stored in a memory.

28. The method of claim 20, further comprising:

detecting a light level at the suspended particle device; and

generating a light level signal wherein the light level signal is used as the voltage level information in the controlling step.

29. The method of claim 20, further comprising:

generating the AC voltage signal at a low frequency.

30. The method of claim 29, wherein the AC voltage signal has a frequency of at least 15 hertz.

31. The method of claim 30, wherein the generating step further comprises:

converting an AC voltage signal of a predetermined frequency into a DC voltage signal;

driving a DC motor with the DC voltage signal; and

generating an AC voltage signal having the low frequency via a generator powered by the DC motor.

32. The method of claim 30, wherein the generating step further includes:

connecting a plurality of solar cells in series to at least one rechargeable battery;

converting a DC voltage signal from the at least one rechargeable battery into an AC voltage signal with the low frequency with a DC/AC converter; and

recharging the at least one rechargeable battery with a recharging voltage signal supplied by the plurality of solar cells.

33. The method of claim 32, further comprising:

mounting the solar cells, the DC/AC converter and the at least one rechargeable battery in a movable support in which the suspended particle device is mounted.

34. The method of claim 20, wherein construction of the suspended particle device comprises:

providing a first conducting layer;

providing a second conducting layer;

positioning an emulsion including a plurality of suspended particles, which align in a predetermined pattern when exposed to an electric field between the first conducting layer and the second conducting layer;

positioning a first conducting bus on the first connecting layer to connect the first conducting layer to the SPD terminal

positioning a second conducting bus on the second conducting layer to connect the second conducting layer to the SPD terminal, such that the first conducting bus and the second conducting bus are positioned on one edge of the suspended particle device.

35. The method of claim 34, wherein a length of the one edge of the suspended particle device is less than a length of another edge of the suspended particle device such that the suspended particle device is substantially rectangular in shape.

36. The method of claim 34, wherein a bus length of the first conducting bus and the second conducting bus is less than a length of the one edge of the suspended particle device.

37. A system of controlling voltage which comprises:

a voltage controlling device, wherein

the voltage controlling device includes;

an AC terminal adapted to receive an AC voltage at a specific frequency;

a voltage dividing device adapted to divide the AC voltage into a plurality of distinct voltage values within a predetermine range;

a controller adapted to control the voltage dividing device to provide a selected voltage value based on voltage level information;

an SPD terminal device adapted to receive the selected voltage value; and

a suspended particle device, wherein

the suspended particle device includes;

a first conducting layer;

a second conducting layer;

an emulsion including a plurality of suspended particles, which align in a predetermined pattern when exposed to an electric field, where the emulsion positioned between the first conducting layer and the second conducting layer,

a first connecting bus connecting the first conducting layer to the SPD terminal; and

a second conducting bus connecting the second conducting layer to the SPD terminal.

38. The system of claim 37, wherein the voltage dividing device further comprises:

a capacitor array including a plurality of capacitors where each capacitor in the capacitor array has a predetermined capacitance; and

a switch array, connecting the capacitor array to the SPD terminal such that each switch of the switch array connects one capacitor of the capacitor array to the SPD terminal, wherein

the controller controls the switches of the switch array to connect at least one of the capacitors of the capacitor array to the SPD terminal based on the voltage level information.

39. The system of claim 38, wherein the capacitor array includes 8 capacitors, and the switch array includes 8 switches, respectively connecting each of the eight capacitors to the SPD terminal, such that the voltage dividing device is capable of providing a total of 256 different voltages to the SPD terminal.

40. The system of claim 37, wherein the predetermined range of distinct voltages provided by the voltage dividing device is sufficiently large to provide a maximum voltage to the SPD terminal sufficient to operate a suspended particle device of a corresponding size.

41. The system of claim 37, wherein the voltage controlling device further comprises:

an input device adapted to provide the voltage level information from a user of the system.

42. The system of claim 37, wherein the controller monitors an SPD voltage provided to the SPD terminal and controls the voltage dividing device to provide zero voltage to the SPD terminal after the SPD voltage drops a predetermined amount below a predetermined level.

43. The system of claim 42, wherein the voltage controlling device further comprises:

an alarm, wherein the controller provides an alarm signal that activates the alarm after the SPD voltage exceeds the predetermined level by a predetermined amount.

44. The system of claim 42, wherein the predetermined level is based on an average value of the SPD voltage over a predetermined period of time.

45. The system of claim 42, wherein the predetermined level is stored in a memory of the controller.

46. The system of claim 37, wherein the voltage controlling device further comprises:

a photo detector adapted to monitor a level of light at the suspended particle device, wherein the level of light at the suspended particle is used as the voltage level information utilized by the controller to control the voltage provided to the SPD terminal by the voltage dividing device.

47. The system of claim 37 wherein the voltage controlling device further comprises:

an AC power supply providing an AC voltage signal at a low frequency to the AC terminal.

48. The system of claim 47, wherein the AC power supply provides an AC voltage signal with a frequency of at least 15 hertz.

49. The system of claim 47, wherein the AC power supply comprises:

an AC/DC converter converting an AC voltage signal of a predetermine frequency into a DC voltage signal;

a DC motor operated by the DC voltage signal; and

a generator connected to the DC motor to provide an AC voltage signal at the low frequency.

50. The system of claim 47, wherein the AC power supply further comprises:

a plurality of solar cells connected in parallel;

at least one rechargeable battery adapted to provide a DC voltage signal;

a converter, adapted to convert the DC voltage signal of the battery into an AC voltage signal with the low frequency;

wherein

the at least one rechargeable battery is recharged by a recharging voltage signal supplied by the plurality of solar cells.

51. The system of claim 50, wherein the AC power supply is mounted in a movable support in which the suspended particle device is mounted, such that the AC power source moves with the suspended particle device.

52. The system of claim 37, wherein the first connecting bus and the second connecting bus of the suspended particle device are connected to the first conducting layer and the second conducting layer, respectively, on one edge of the suspended particle device.

53. The system of claim 52, wherein a length of the one edge of the suspended particle device is less than a length of another edge of the suspended particle device such that the suspended particle device is substantially rectangular in shape.

54. The system of claim 52, wherein a bus length of the first connecting bus and the second connecting bus, respectively, is less than a length of the one edge of the suspended particle device.