Electrochromic devices with patterned electrically conductive layers
View Patent ↗An electrochromic device is provided. The device includes a first transparent substrate and a second transparent substrate and a first electrically conductive layer and a second electrically conductive layer. A first bus bar is in contact with the first electrically conductive layer and a second bus bar in contact with the second electrically conductive layer. The first and second electrically conductive layers are patterned with sets of scribed lines substantially parallel to the corresponding bus bar, wherein the sets of scribed lines are made up of a series of collinear segments, which are gaps in the electrically conductive layer, wherein the length of the collinear segments, the period, the valve width and the offset between segments in adjacent scribed lines determines the resistance to the flow of electrons traversing a set of scribed lines in the direction substantially perpendicular to the corresponding bus bar.
1. An electrochromic device, comprising:
a first transparent substrate and a second transparent substrate;
a first electrically conductive layer and a second electrically conductive layer arranged on respective inner surfaces of the first and second transparent substrates;
a first bus bar in contact with the first electrically conductive layer; and
a second bus bar in contact with the second electrically conductive layer,
wherein: the first electrically conductive layer is patterned with a first plurality of scribed lines in a direction substantially parallel to the first bus bar, wherein the first plurality of scribed lines are made up of a first series of collinear segments comprising gaps in the first electrically conductive layer, and wherein a length of the first series of collinear segments, a period of the first series of collinear segments, a valve width of the first series of collinear segments and an offset between the first series of collinear segments in adjacent scribed lines determine a resistance to a flow of electrons traversing the first plurality of scribed lines in the direction substantially perpendicular to the first bus bar; and
the second electrically conductive layer is patterned with a second plurality of scribed lines in a direction substantially parallel to the second bus bar, wherein the second plurality of scribed lines are made up of a second series of collinear segments, comprising gaps in the second electrically conductive layer, and wherein a length of the second series of collinear segments, a period of the second series of collinear segments, a valve width of the second series of collinear segments and an offset between the second series of collinear segments in adjacent scribed lines determine a resistance to a flow of electrons traversing the second plurality of scribed lines in the direction substantially perpendicular to the second bus bar.
2. The electrochromic device of claim 1 , wherein:
the first electrically conductive layer comprises a first transparent conductive material;
the second electrically conductive layer comprises a second transparent conductive material;
a sheet resistance of the first transparent conductive material without scribed lines as a function of position x is R TC (x);
a sheet resistance of the second transparent conductive material without scribed lines as a function of position x is R TC (x);
the first electrically conductive layer comprises a first N sets of scribed lines, and a resistance to the flow of electrons traversing a first n th set of scribed lines in the first N sets of scribed lines in the direction perpendicular to the first bus bar in the first electrically conductive layer is r n , and is approximated by the function r n =∫{[R(x)−R TC (x)]/W}dx,
evaluated in the interval from [x n−1 , x n ]; and
the second electrically conductive layer comprises a second N sets of scribed lines, and a resistance to the flow of electrons traversing a second n th set of scribed lines in the second N sets of scribed lines in the direction perpendicular to the second bus bar in the second electrically conductive layer is r′ n , and is approximated by the function r′ n =∫{[R′(x)−R TC (x)]/W}dx, evaluated in the interval from [x n+1 , x n ].
3. The electrochromic device of claim 2 , wherein the resistance to the flow of electrons traversing the first n th set of scribed lines in the direction perpendicular to the first bus bar in the first electrically conductive layer is from about 0 Ohm-cm to about 10000 Ohm-cm.
4. The electrochromic device of claim 2 , wherein an average resistance to the flow of electrons traversing the first n th set of scribed lines in the direction perpendicular to the first bus bar in the first electrically conductive layer is from about 0 Ohm-cm to about 1000 Ohm-cm.
5. The electrochromic device of claim 1 , wherein the length of the first and second series of collinear segments in the first and second plurality of scribed lines is from about 0.1 mm to about 100 mm.
6. The electrochromic device of claim 1 , wherein the first bus bar is located at an edge of the electrochromic device wherein the electrochromic device has a substantially rectangular shape.
7. The electrochromic device of claim 1 , wherein a thickness of the first electrically conductive layer is changing.
8. The electrochromic device of claim 1 , wherein an electrical property of the first electrically conductive layer is changing.
9. The electrochromic device of claim 1 , wherein the second bus bar is located at an edge of the electrochromic device wherein the electrochromic device has a substantially rectangular shape.
10. The electrochromic device of claim 1 , wherein a thickness of the second electrically conductive layer is changing.
11. The electrochromic device of claim 1 , wherein an electrical property of the second electrically conductive layer is changing.
12. The electrochromic device of claim 1 , wherein a plurality of visually perceptible patterns exist in the electrochromic device during a switching of the electrochromic device from a more transmissive state to a less transmissive state, or from a less transmissive state to a more transmissive state.
13. The electrochromic device of claim 1 , wherein:
the direction substantially perpendicular to the first bus bar in a plane of the first electrically conductive layer is x;
the direction substantially perpendicular to the second bus bar in a plane of the second electrically conductive layer is x;
a sheet resistance of the first electrically conductive layer is approximated by a function R(x);
a sheet resistance of the second electrically conductive layer is approximated by a function R′(x);
the first bus bar is located approximately at a position x=0;
the second bus bar is located approximately at a position x=x t ; and
the relationship between the sheet resistance of the first electrically conductive layer and the sheet resistance of the second electrically conductive layer approximately follows the relationship R′(x)=R(x)*(x t /x−1).
14. The electrochromic device of claim 13 , wherein:
the sheet resistance of the first electrically conductive layer is approximated by the function R(x)=1/[a*(x t −x)]; and
the sheet resistance of the second electrically conductive layer is approximated by the function R′(x)=1/(a*x+b) where b is small relative to a.
15. The electrochromic device of claim 13 , wherein:
a width of the first electrically conductive layer in the direction substantially parallel to the first bus bar is W;
a width of the second electrically conductive layer in the direction substantially parallel to the second bus bar is also W;
a resistance between the first bus bar and a first line in the first plurality of scribed lines substantially parallel to the first bus bar in the first electrically conductive layer is approximated by a function r(x)=∫[R(x)/W]dx, evaluated in an interval from x=0 to x=x; and
a resistance between the second bus bar and a second line in the second plurality of scribed lines substantially parallel to the second bus bar in the second electrically conductive layer is approximated by a function r′(x)=∫[R′(x)/W]dx, evaluated in an interval from x=x to x=x t .