Driver for electrochromic glass unit

• US 10,831,079 B2
• Filed: 01/13/2017
• Issued: 11/10/2020
• Est. Priority Date: 01/12/2015
• Status: Active Grant

• Current Assignee: Halio Incorporated
• Original Assignee: Kinestral Technologies, Inc.
• Inventors: Ziebarth, Jonathan, Bergh, Howard S.
• Primary Examiner(s): Huang, Wen
• Application Number:
  US15/406,576
• Publication Number:
  US 20170192335A1
• Time in Patent Office: 1,397 Days
• Field of Search: 359237-239, 359245, 359265-267, 359271, 359275, 245105, 245204, 245211, 245214, 245690
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors
• 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: G01R 19/003 Measuring mean values of current or voltage during a given time interval
• CPC Class Codes: G02F 1/0121 Operation of devices; Circuit arrangements, not otherwise provided for in this subclass
• CPC Class Codes: G02F 1/0123 Circuits for the control or stabilisation of the bias voltage, e.g. automatic bias control [ABC] feedback loops
• CPC Class Codes: G02F 1/155 Electrodes
• CPC Class Codes: G02F 1/163 Operation of electrochromic cells, e.g. electrodeposition cells; Circuit arrangements therefor
• CPC Class Codes: G02F 2001/1635 the pixel comprises active switching elements, e.g. TFT
• CPC Class Codes: G05B 19/0428 Safety, monitoring G05B19/0423 takes precedence
• CPC Class Codes: G05B 2219/23104 Change display of window to another as function of settable active display time of window
• CPC Class Codes: G05B 2219/2628 Door, window
• CPC Class Codes: G09G 3/16 by control of light from an independent source
• CPC Class Codes: G09G 3/19 using electrochromic devices
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks

Abstract

A method for controlling an electrochromic device is provided. The method includes applying a constant supply current to the electrochromic device and determining an amount of charge transferred to the electrochromic device, as a function of time and current supplied to the electrochromic device. The method includes ceasing the applying the constant supply current, responsive to a sense voltage reaching a sense voltage limit and applying one of a variable voltage or a variable current to the electrochromic device to maintain the sense voltage at the sense voltage limit, responsive to the sense voltage reaching the sense voltage limit. The method includes terminating the applying the variable voltage or the variable current to the electrochromic device, responsive to the determined amount of charge reaching a target amount of charge.

Claims

1. A method for controlling an electrochromic device, comprising:

determining an amount of charge transferred to the electrochromic device, as a function of time and current supplied to the electrochromic device;

applying one of a variable voltage or a variable current to the electrochromic device to maintain a sense voltage, measured at one or more sense voltage terminals of the electrochromic device, at a sense voltage limit, responsive to the sense voltage reaching the sense voltage limit, wherein the one or more sense voltage terminals are distinct from voltage source bus bars of the electrochromic device;

terminating the applying the variable voltage or the variable current to the electrochromic device, responsive to the determined amount of charge reaching a target amount of charge;

reversing a polarity of a reversible constant current supply, wherein the reversible constant current supply applies a constant supply current with the reversed polarity to the electrochromic device;

reversing a polarity of a reversible variable voltage supply, wherein the reversible variable voltage supply applies the variable voltage with the reversed polarity to the electrochromic device, and wherein the sense voltage limit is zero volts; and

delaying the terminating for a predetermined amount of time during which the sense voltage is held at zero volts.

2. The method of claim 1, wherein terminating occurs after reaching a desired transmissivity of the electrochromic device equating to the target amount of charge.

3. The method of claim 1, further comprising:

measuring the sense voltage of the electrochromic device; and

measuring a current supplied to the electrochromic device, wherein determining the amount of charge is based on summing digital values of the current over a span of time.

4. The method of claim 1, wherein determining the amount of charge transferred to the electrochromic device comprises:

integrating, over time, a current supplied to the electrochromic device.

5. The method of claim 1, wherein once the amount of charge transferred equals the target amount of charge to be transferred the driver starts voltage process comprising measuring voltage at the one or more sense voltage terminals.

6. The method of claim 1, wherein the sense voltage is held at zero volts to rezero the driver as to the state of charge of the electrochromic device.

7. The method of claim 1, wherein determining the amount of charge transferred to the electrochromic device further comprises:

applying analog to digital conversion to a current supplied to the electrochromic device, to produce a digital value of the current supplied to the electrochromic device; and

adding values from a time series of the digital value of the current supplied to the electrochromic device.

8. The method of claim 1, wherein:

the variable voltage or the variable current is supplied to the voltage source bus bars of the electrochromic device; and

the sense voltage is measured from the one or more sense voltage terminals of the electrochromic device located elsewhere on the electrochromic device than the voltage source bus bars.

9. The method of claim 1 wherein the sense voltage is measured from an edge of the electrochromic device.

10. The method of claim 1, further comprising:

monitoring the sense voltage; and

applying one of a charge or a discharge to the electrochromic device, responsive to a deviation of the sense voltage, after a predetermined relaxation time, by more than a predetermined relaxation amount of voltage.

11. The method of claim 1 wherein if a state of charge does not match the target amount of charge a sequestration process is initiated.

12. The method of claim 1, wherein a sequestration process is initiated every time a fully bleached state is met.