Method for detecting breakage of substrate of a switchable optical element and switchable optical device

Patent metadata

Field	Value
Publication number	US-11112626-B2
Application number	US-201816481719-A
Country	US
Kind code	B2
Filing date	Jan 24, 2018
Priority date	Jan 27, 2017
Publication date	Sep 7, 2021
Grant date	Sep 7, 2021

Abstract

A switchable optical element and method for detecting breakage of a substrate (A, B) of at least one switchable optical element ( 10 ) having a first substrate (A) and a second substrate (B), the first substrate (A) being coated with a first electrode and the second substrate (B) being coated with a second electrode, and a switchable layer ( 14 ), the switchable layer ( 14 ) being sandwiched between the first substrate (A) and second substrate (B), the first electrode and second electrode each having at least one contact, by
i) measuring a change in a differential signal measured at two contacts of a substrate (A, B),
ii) measuring a change in capacitance between the two substrates (A, B),
iii) measuring a change in resistance of at least one of the substrates (A, B),
iv) measuring a change in current applied to the switchable optical element ( 10 ).

First claim

The invention claimed is:

1. A method for detecting breakage of a substrate (A, B) of at least one
switchable optical element ( 10 ),
the at least one switchable optical element ( 10 ) comprising
a first substrate (A) and a second substrate (B),
the first substrate (A) being coated with a first electrode and the second substrate (B) being coated with a second electrode, and
a switchable layer ( 14 ), the switchable layer ( 14 ) being sandwiched between the first substrate (A) and second substrate (B),
the first electrode and second electrode each having at least one contact (A 1 , A 2 , B 1 , B 2 ),
the method comprising
i)
a) applying an electric field between the first electrode and the second electrode by applying a test signal provided by a test signal source to the at least one switchable optical element ( 10 ), wherein the test signal is an AC signal, and
wherein
an output of the test signal source is split into two signal lines ( 21 , 22 , 21 ′, 22 ′),
the first electrode having at least two contacts and each signal line ( 21 , 22 , 21 ′, 22 ′) being connected with another one of the contacts (A 1 , A 2 ) of the first electrode,
and the at least one contact (B 1 , B 2 ) of the second electrode being connected to a reference potential ( 26 ),
b) measuring of a differential signal between the two signal lines ( 21 , 22 , 21 ′, 22 ′), and
c) detecting a broken substrate if at least one parameter of the differential signal exceeds a predetermined threshold or if a change of at least one parameter of the differential signal exceeds a predetermined threshold,
and/or the method comprising
ii)
a) measuring a capacitance (C 1 , C 2 ) between one contact (A 1 , A 2 ) of the first electrode and one contact (B 1 , B 2 ) of the second electrode, and
b) detecting a broken substrate if the measured capacitance (C 1 , C 2 ) is below a predetermined threshold or if a change in the measured capacitance (C 1 , C 2 ) exceeds a predetermined threshold,
and/or the method comprising
iii)
a) measuring an electrical resistance (R 1 ) between two contacts (A 1 , A 2 ) of the first electrode and/or measuring an electrical resistance (R 2 ) between two contacts (B 1 , B 2 ) of the second electrode, the first electrode and/or second electrode having at least two contacts (A 1 , A 2 , B 1 , B 2 ), and
b) detecting a broken substrate if the measured resistance (R 1 , R 2 ) exceeds a predetermined threshold or if a change in the measured resistance (R 1 , R 2 ) exceeds a predetermined threshold,
and/or the method comprising
iv)
a) applying an electric field between the first electrode and the second electrode by applying an AC driving signal to the at least one contact (A 1 , A 2 ) of the first electrode and to the at least one contact (B 1 , B 2 ) of the second electrode, the AC driving signal being configured to switch and/or hold the switchable optical element ( 10 ) in one of the states of the switchable optical element ( 10 ),
b) measuring a current of the AC driving signal, and
c) detecting a broken substrate if the measured current exceeds a predetermined threshold or if a change in the measured current exceeds a predetermined threshold.

2. The method of claim 1 , wherein the test signal of variant i) is a periodic signal with a frequency different from the frequency of an AC driving signal, the AC driving signal being configured to switch and/or hold the switchable optical element ( 10 ) in one of the states of the switchable optical element ( 10 ).

3. The method of claim 1 , wherein the test signal of variant i) has a frequency of from 1 kHz to 1000 kHz.

4. The method of claim 1 , wherein the peak to peak voltage of the test signal of variant i) is in the range of from 10 mV to 1000 mV.

5. The method of claim 1 , wherein the test signal of variant i) is combined with the AC driving signal of the switchable optical element ( 10 ) so that a sum signal comprising the test signal and the AC driving signal is applied to the first electrode and the second electrode of the switchable optical element ( 10 ).

6. The method of claim 1 , wherein at least one parameter of variant i) and/or a change of the capacitance (C 1 , C 2 ) of variant ii) and/or a change of the resistance (R 1 , R 2 ) of variant iii) and/or a change of the current of variant iv), is determined by comparing the respective measured value to a floating average of previously measured values.

7. The method of claim 1 , wherein at least one reference value for a parameter of variant i) and/or a reference resistance of variant ii) and/or a reference capacitance of variant iii) and/or a reference current of variant iv), is set in an initial calibration measurement.

8. The method of claim 1 , wherein at least two switchable optical elements ( 10 ) are connected in parallel.

9. The method of claim 1 , wherein the switchable optical element ( 10 ) is part of a window of a building or a vehicle.

10. A switchable optical device comprising at least one switchable optical element ( 10 ) and a first signal generator for generating an AC driving signal, the at least one switchable optical element comprising a first substrate (A) and a second substrate (B), the first substrate (A) being coated with a first electrode and the second substrate (B) being coated with a second electrode, and a switchable layer ( 14 ), the switchable layer ( 14 ) being sandwiched between the first substrate (A) and second substrate (B), the first electrode and second electrode each having at least one contact (A 1 , A 2 , B 1 , B 2 ),
wherein
the switchable optical device further comprises
i) a second signal generator generating a test signal, the test signal being an AC signal, a measuring unit and an evaluation unit, the output of the second signal generator being split into two signal lines ( 21 , 22 , 21 ′, 22 ′), the first electrode having at least two contacts (A 1 , A 2 ) and each signal line ( 21 , 22 , 21 ′, 22 ′) being connected to another one of the at least two contacts (A 1 , A 2 ) of the first electrode and at least one contact (B 1 , B 2 ) of the second electrode being connected to a reference potential ( 26 ),
the measuring unit being connected to the two signal lines ( 21 , 22 , 21 ′, 22 ′), the measuring unit being configured for measuring a differential signal, and the evaluation unit being configured to detect a broken substrate if at least one parameter of the differential signal exceeds a predetermined threshold or if a change of at least one parameter of the differential signal exceeds a predetermined threshold,
and/or
ii) a measuring unit and an evaluation unit, the measuring unit being configured to measure a capacitance (C 1 , C 2 ) between one contact (A 1 , A 2 ) of the first electrode and one contact (B 1 , B 2 ) of the second electrode and the evaluation unit being configured to detect a broken substrate if the measured capacitance (C 1 , C 2 ) is below a predetermined threshold or if a change of the measured capacitance (C 1 , C 2 ) exceeds a predetermined threshold,
and/or
iii) a measuring unit and an evaluation unit, the first electrode and/or the second electrode having at least two contacts (A 1 , A 2 , B 1 , B 2 ) and the measuring unit being configured to measure an electrical resistance (R 1 , R 2 ) between the two contacts (A 1 , A 2 , B 1 , B 2 ) of at least one of the first electrode and the second electrode and the evaluation unit being configured to detect a broken substrate if the measured resistance (R 1 , R 2 ) exceeds a predetermined threshold or if a change of the measured resistance (R 1 , R 2 ) exceeds a predetermined threshold,
and/or
iv) a measuring unit and an evaluation unit, the measuring unit being

Assignees

• Merck Patent Gmbh

Inventors

• De Jong Ties
• Bakker Paul

Classifications

• 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

• E06B7/28

  Other arrangements on doors or windows, e.g. door-plates, windows adapted to carry plants, hooks for window cleaners {(edge protecting devices for door leaves E06B3/88; special glazing; emergency glazing; double glazing E06B3/66)} · CPC title

• B60J3/04

  adjustable in transparency · CPC title

• G02F1/1309 Primary

  Repairing; Testing · CPC title

• E06B2009/2464

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