Electrochromic devices with patterned electrically conductive layers
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;
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 sets of scribed lines substantially parallel to the first 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 first bus bar, and
the second electrically conductive layer is patterned with sets of scribed lines substantially parallel to the second 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 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,
the sheet resistance of the first transparent conductive material without scribed lines as a function of position x is R TC (x),
the 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 N sets of scribed lines, and the resistance to the flow of electrons traversing the n th set 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 N sets of scribed lines, and the resistance to the flow of electrons traversing the n th set 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 1 , wherein the resistance to the flow of electrons traversing the 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 1 , wherein the average resistance to the flow of electrons traversing the 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 collinear segments in the sets of scribed lines are from about 0.1 mm to about 100 mm.
6. The electrochromic device of claim 1 , wherein the first bus bar is located at one edge of the electrochromic device that has a substantially rectangular shape.
7. The electrochromic device of claim 1 , wherein the first electrically conductive layer is patterned.
8. The electrochromic device of claim 1 , wherein the thickness of the first electrically conductive layer is changing.
9. The electrochromic device of claim 1 , wherein the electrical properties of the first electrically conductive layer is changing.
10. The electrochromic device of claim 1 , wherein the second bus bar is located at one edge of the electrochromic device.
11. The electrochromic device of claim 1 , wherein the second electrically conductive layer is patterned.
12. The electrochromic device of claim 1 , wherein the thickness of the second electrically conductive layer is changing.
13. The electrochromic device of claim 1 , wherein the electrical properties of the second electrically conductive layer is changing.
14. The electrochromic device of claim 1 , wherein
visually perceptible patterns exist in the device during switching from a more transmissive state to a less transmissive state, or from a less transmissive state to a more transmissive state.
15. The electrochromic device of claim 1 , wherein
the direction perpendicular to the first bus bar in the plane of the first electrically conductive layer is x,
the direction perpendicular to the second bus bar in the plane of the second electrically conductive layer is x,
the sheet resistance of the first electrically conductive layer is approximated by a function R(x),
the 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 and second electrically conductive layers approximately follow the relationship R′(x)=R(x)*(x t /x−1).
16. The electrochromic device of claim 15 , 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.
17. The electrochromic device of claim 15 , wherein
the width of the first electrically conductive layer in the direction substantially parallel to the first bus bar is W,
the width of the second electrically conductive layer in the direction substantially parallel to the second bus bar is also W,
the resistance between the first bus bar and a first line substantially parallel to the first bus bar in the first electrically conductive layer is approximated by the function r(x)=∫[R(x)/W] dx, evaluated in the interval from x=0 to x=x, and
the resistance between the second bus bar and a second line substantially parallel to the second bus bar in the second electrically conductive layer is approximated by the function r′(x)=∫[R′(x)/W] dx, evaluated in the interval from x=x to x=x t .
18. The electrochromic device of claim 17 , wherein
the first substrate is approximately rectangular,
the first substrate is approximately 75 cm long in the direction perpendicular to the first bus bar and 130 cm wide in the direction parallel to the first bus bar,
the pitch between sets of scribed lines in the first and second electrically conductive layers is approximately 5 cm, and
the resistance to the flow of electrons traversing the 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.