Driving thin film switchable optical devices

Patent metadata

Field	Value
Publication number	US-12197098-B2
Application number	US-202418410118-A
Country	US
Kind code	B2
Filing date	Jan 11, 2024
Priority date	Apr 17, 2012
Publication date	Jan 14, 2025
Grant date	Jan 14, 2025

Abstract

Controllers and control methods apply a drive voltage to bus bars of a thin film optically switchable device. The applied drive voltage is provided at a level that drives a transition over the entire surface of the optically switchable device but does not damage or degrade the device. This applied voltage produces an effective voltage at all locations on the face of the device that is within a bracketed range. The upper bound of this range is associated with a voltage safely below the level at which the device may experience damage or degradation impacting its performance in the short term or the long term. At the lower boundary of this range is an effective voltage at which the transition between optical states of the device occurs relatively rapidly. The level of voltage applied between the bus bars is significantly greater than the maximum value of the effective voltage within the bracketed range.

First claim

The invention claimed is:

1. An electrochromic device and control system comprising:
a thin film electrochromic device comprising bus bars; and
a controller comprising:
circuitry for applying voltage or providing instructions to apply voltage between the bus bars on the thin film electrochromic device;
a processing component configured to perform the following operations:
(a) receive an analog signal of between 0-10 V, the analog signal indicating a target optical state of the thin film electrochromic device;
(b) interpret the analog signal using logic, and, in response, produce a first voltage; and
(c) generate a second voltage based on the first voltage, and apply the second voltage to the bus bars in electrical communication with the thin film electrochromic device to thereby cause the thin film electrochromic device to change to the target optical state in a manner specified by the analog signal,

wherein the bus bars of the thin film electrochromic device are electrically coupled to the controller.

2. The electrochromic device and control system of claim 1 , wherein the analog signal is a tint command signal (V TC ) that indicates the target optical state of the thin film electrochromic device, the target optical state being specified by a user.

3. The electrochromic device and control system of claim 1 , the controller further comprising a signal conditioner configured to receive the analog signal.

4. The electrochromic device and control system of claim 3 , the controller further comprising a microcontroller, wherein the signal conditioner is configured to generate a conditioning signal (V CON ) based on the received analog signal, wherein the conditioning signal (V CON ) is the first voltage, and wherein the microcontroller is configured to generate a command signal (V COMMAND ) based on the conditioning signal (V CON ).

5. The electrochromic device and control system of claim 4 , the controller further comprising a pulse width modulator, wherein the pulse width modulator is configured to receive the command signal (V COMMAND ) and to generate the second voltage based on the received command signal (V COMMAND ).

6. The electrochromic device and control system of claim 5 , wherein the pulse width modulator generates a current feedback signal (I FB ) and/or a voltage feedback signal (V FB ), and wherein the microcontroller is configured to use the current feedback signal GM and/or the voltage feedback signal (V FB ) to generate the command signal (V COMMAND ).

7. The electrochromic device and control system of claim 3 , wherein the signal conditioner is also configured to receive feedback from one or more sensors selected from the group consisting of: an exterior photosensor or photodetector, an interior photosensor or photodetector, and a thermal or temperature sensor.

8. The electrochromic device and control system of claim 1 , wherein the second voltage comprises a positive component (V PW1 ) and a negative component (V PW2 ), and wherein the positive component (V PW1 ) and negative component (V PW2 ) of the second voltage are supplied in pulses having unequal durations.

9. The electrochromic device and control system of claim 1 , wherein the second voltage applied to the bus bars has a magnitude such that an area of the thin film electrochromic device between the bus bars experiences an effective voltage between a maximum effective voltage that avoids damaging the thin film electrochromic device and a minimum effective voltage that drives the change in optical state of the thin film electrochromic device, wherein the second voltage is greater than the maximum effective voltage.

10. The electrochromic device and control system of claim 9 , wherein the second voltage has a magnitude that is between about 2.3-6V.

11. The electrochromic device and control system of claim 1 , wherein the bus bars of the thin film electrochromic device are separated by a distance of at least about 30 inches.

12. An electrochromic device and control system comprising:
a thin film electrochromic device comprising bus bars and transparent conductive layers; and
a controller comprising:
circuitry for applying voltage or providing instructions to apply voltage between the bus bars on the thin film electrochromic device; and
a processing component configured to perform the following operations:
supplying an applied voltage (V app ) to the bus bars to transition the thin film electrochromic device from a first optical state to a second optical state,
wherein the V app is supplied such that V min <(V app −0.5RJL 2 )<V max for all local positions between the bus bars on the thin film electrochromic device, where
R is a sheet resistance of the transparent conductive layers,
J is a local current density on the thin film electrochromic device,
L is an effective separation distance between the bus bars,
V min is a minimum operating voltage to effect the transition from the first optical state to the second optical state on the thin film electrochromic device, and
V max is a maximum safe operating voltage of the thin film electrochromic device that will not damage the thin film electrochromic device,

wherein the bus bars of the thin film electrochromic device are electrically coupled to the controller.

13. The electrochromic device and control system of claim 12 , wherein the V max is about 4 V or less.

14. The electrochromic device and control system of claim 12 , wherein the V min is about 0.5 V or greater.

15. The electrochromic device and control system of claim 12 , wherein the V min is about 1.2 V or greater, and wherein the V max is about 2.5 V or less.

16. The electrochromic device and control system of claim 12 , wherein the V app is supplied at a magnitude between about 2.3-6 V.

17. The electrochromic device and control system of claim 12 , wherein the V app is supplied such that (V app −0.5RJL 2 )<V max −V buffer , wherein the V buffer is between about 0.2-0.6 V.

18. The electrochromic device and control system of claim 12 , wherein the bus bars of the thin film electrochromic device are separated by a distance of at least about 30 inches.

19. The electrochromic device and control system of claim 12 , wherein the V app is supplied at a magnitude that is between about 0.5-2 V greater than a magnitude of the V max .

Assignees

• View Inc

Inventors

• Pradhan Anshu A
• Mehtani Disha
• Jack Gordon

Classifications

• G02F1/155

  Electrodes · CPC title

• G02F2001/1555

  Counter electrode · CPC title

• G02F1/163 Primary

  Operation of electrochromic cells, e.g. electrodeposition cells; Circuit arrangements therefor · CPC title