Controlling transitions in optically switchable devices

Patent metadata

Field	Value
Publication number	US-11829045-B2
Application number	US-202117444010-A
Country	US
Kind code	B2
Filing date	Jul 29, 2021
Priority date	Jun 28, 2013
Publication date	Nov 28, 2023
Grant date	Nov 28, 2023

Abstract

Aspects of this disclosure concern controllers and control methods for applying a drive voltage to bus bars of optically switchable devices such as electrochromic devices. Such devices are often provided on windows such as architectural glass. In certain embodiments, the applied drive voltage is controlled in a manner that efficiently drives an optical transition over the entire surface of the electrochromic device. The drive voltage is controlled to account for differences in effective voltage experienced in regions between the bus bars and regions proximate the bus bars. Regions near the bus bars experience the highest effective voltage. In some cases, feedback may be used to monitor an optical transition. In these or other cases, a group of optically switchable devices may transition together over a particular duration to achieve approximately uniform tint states over time during the transition.

First claim

What is claimed is:

1. An apparatus for controlling a first optical transition and a second optical transition of an optically switchable device, the apparatus comprising:
a processor configured to:
(a) receive a command to undergo the first optical transition from a starting optical state to a first ending optical state;
(b) apply a first drive parameter to bus bars of the optically switchable device and drive the first optical transition for a first duration; and
(c) before the optically switchable device reaches the first ending optical state:
(i) receive a second command to undergo the second optical transition to a second ending optical state, and
(ii) apply a second drive parameter to the bus bars of the optically switchable device and drive the second optical transition for a second duration, wherein the second drive parameter is different from the first drive parameter, wherein the second drive parameter is determined based, at least in part, on the second ending optical state and an amount of charge delivered to the optically switchable device during the first optical transition toward the first ending optical state, and wherein the processor is configured to control the second optical transition without considering an open circuit voltage of the optically switchable device.

2. The apparatus of claim 1 , wherein the processor is further configured to monitor an amount of charge delivered to the optically switchable device during the second optical transition to the second ending optical state, and cease to apply the second drive parameter to bus bars of the optically switchable device based, at least in part, on the amount of charge delivered to the optically switchable device during the second optical transition to the second ending optical state.

3. The apparatus of claim 1 , wherein (c)(ii) comprises:
after (i), determine the amount of charge delivered to the optically switchable device during the first optical transition toward the first ending optical state,
determine a target charge count that is appropriate for causing the optically switchable device to switch from the starting optical state to the second ending optical state,
monitor an amount of charge delivered to the optically switchable device during the second optical transition to the second ending optical state, and
apply the second drive parameter to the bus bars of the optically switchable device until a net amount of charge delivered to the optically switchable device during the first and second optical transitions reaches the target charge count.

4. The apparatus of claim 1 , wherein (c)(ii) comprises:
determine or estimating an instantaneous optical state of the optically switchable device when the second command was received in (c)(i) based, at least in part, on the amount of charge delivered to the optically switchable device during the first optical transition toward the first ending optical state,
determining a target charge count that is appropriate for causing the optically switchable device to switch from its instantaneous optical state to the second ending optical state,
monitoring an amount of charge delivered to the optically switchable device during the second optical transition to the second ending optical state, and
applying the second drive parameter to the bus bars of the optically switchable device until the amount of charge delivered to the optically switchable device during the second optical transition reaches the target charge count.

5. The apparatus of claim 1 , wherein driving the first optical transition in (b) comprises:
applying the first drive parameter to the bus bars of the optically switchable device,
determining a target open circuit voltage appropriate for switching the optically switchable device from the starting optical state to the first ending optical state, and determining a target charge count appropriate for switching the optically switchable device from the starting optical state to the first ending optical state,
periodically determining an open circuit voltage between the bus bars of the optically switchable device, and periodically or continuously determining the amount of charge delivered to the optically switchable device during the first optical transition toward the first ending optical state, and
periodically comparing the determined open circuit voltage to a target open circuit voltage and periodically comparing the amount of charge delivered to the optically switchable device during the first optical transition toward the first ending optical state to a first target charge count.

6. The apparatus of claim 1 , wherein the processor is configured to receive additional commands to undergo additional optical transitions before the optically switchable device reaches the second ending optical state, and apply additional drive parameters to bus bars of the optically switchable device, wherein the additional drive parameters are determined based, at least in part, on target ending optical states for the additional optical transitions and an amount of charge delivered to the optically switchable device between a time that the optically switchable device transitions from its starting optical state and a time that the additional optical transitions begin, wherein the processor is configured to control the additional optical transitions without considering the open circuit voltage of the optically switchable device.

7. An apparatus for controlling an optical transition in an optically switchable device from a starting optical state to an ending optical state, the apparatus comprising:
a processor configured to:
(a) apply a drive voltage to bus bars of the optically switchable device for a duration to cause the optically switchable device to transition toward the ending optical state;
(b) determine an open circuit voltage between the bus bars of the optically switchable device;
(c) compare the open circuit voltage to a target open circuit voltage for the optical transition;
(d) compare the open circuit voltage to a safe voltage limit for the optically switchable device, and either:
(i) increasing the drive voltage in response to the open circuit voltage being less than the safe voltage limit for the optically switchable device, or
(ii) decreasing the drive voltage in response to the open circuit voltage being greater than the safe voltage limit for the optically switchable device; and

(e) repeating at least operations (a)-(C) at least once; and
(f) determining that the open circuit voltage has reached the target open circuit voltage, ceasing application of the drive voltage to the bus bars of the optically switchable device, and applying a hold voltage to the bus bars of the optically switchable device to thereby maintain the ending optical state.

8. The apparatus of claim 7 ,
wherein (b) further comprises determining an amount of charge delivered to the optically switchable device over a course of the optical transition,
wherein (c) further comprises comparing the amount of charge delivered to the optically switchable device over the course of the optical transition to a target charge count for the optical transition, and
wherein (f) further comprises determining that the amount of charge delivered to the optically switchable device over the course of the optical transition has reached the target charge count for the optical transition before applying the hold voltage to the bus bars of the optically switchable device.

9. An apparatus for controlling optical transitions in a group of optically switchable devices, the apparatus comprising:
a processor configured to:
(a) receive a command to transition the group of optically switchable devices to an ending optical state, wherein the gro

Assignees

• View Inc

Inventors

• Jack Gordon
• Kailasam Sridhar K
• Brown Stephen C
• Pradhan Anshu A

Classifications

• G02F1/163 Primary

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

• E06B3/6722

  with adjustable passage of light · CPC title

• E06B9/24

  Screens or other constructions affording protection against light, especially against sunshine; Similar screens for privacy or appearance; {Slat blinds}(operating, guiding or securing devices or arrangements for roll-type closures E06B9/56; free-hanging flexible screens A47H23/00) · CPC title

• G02F1/0121

  Operation of devices; Circuit arrangements, not otherwise provided for in this subclass · CPC title

• E06B2009/2464

  featuring transparency control by applying voltage, e.g. LCD, electrochromic panels · CPC title