Electro-optic element buss

Abstract

An electro-optic element is provided that includes: a first substrate having a first surface, a second surface, and a first edge having alternating first tabs and notches; a first electrode on the second surface; a second substrate having a third surface, a fourth surface, and a second edge having alternating second tabs and notches, the second and third surfaces are parallel with the first tabs and second notches aligned and the second tabs and first notches aligned; a second electrode on the third surface; an electro-optic medium between the first and second electrodes; a first buss disposed on the first surface along the first tabs while extending within the first notches to electrically contact the second electrode on the second tabs; and a second buss disposed on the fourth surface along the second tabs while extending within the second notches to electrically contact the first electrode on the first tabs.

Description

Atty. Docket No. AUTO 05170T (GEN010 FP1393AWO)ELECTRO-OPTIC ELEMENT BUSSCROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims priority under 35 U.S.C. §119(e) upon U.S. Provisional Patent Application No. 63 / 679,907, entitled "ELECTRO-OPTIC ELEMENT BUSS" filed on August 6, 2025, by Matthew A. Koppey et al., the entire disclosure of which is incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure generally relates to a buss for an electro-optic element and more particularly to a buss for an electro-optic element of a large area device (LAD) such as a vehicle window or sunroof or an architectural window.SUMMARY

[0003] According to one aspect of the present disclosure, an electro-optic element is provided that includes: a first transparent substrate having a first surface, a second surface opposite the first surface, and a first peripheral edge extending around the perimeter of the first transparent substrate, wherein the first peripheral edge is crenulated so as to have alternating first tabs and first notches; a first transparent electrically conductive layer disposed on the second surface; a second transparent substrate having a third surface, a fourth surface opposite the third surface, and a second peripheral edge extending around the perimeter of the second transparent substrate, wherein the second peripheral edge is crenulated so as to have alternating second tabs and second notches, wherein the first and second transparent substrates are arranged such that the second and third surfaces are substantially parallel with the first tabs aligned with the second notches and the second tabs aligned with the first notches; a second transparent electrically conductive layer disposed on the third surface; an electrooptic medium disposed between the first and second electrically conductive layers; a first buss disposed on the first surface along the first tabs while extending within the first notches so as to electrically contact the second transparent electrically conductive layer on the second tabs without electrically contacting the first transparent electrically conductive layer; and a second buss disposed on the fourth surface along the second tabswhile extending within the second notches so as to electrically contact the first transparent electrically conductive layer on the first tabs without electrically contacting the second transparent electrically conductive layer.

[0004] It is another aspect of the present disclosure to provide an electro-optic element including: a first transparent substrate having a first surface, a second surface opposite the first surface, and a first peripheral edge extending around the perimeter of the first transparent substrate, wherein the first peripheral edge is crenulated to have alternating first tabs and first notches; a first transparent electrically conductive layer disposed on the second surface; a second transparent substrate having a third surface, a fourth surface opposite the third surface, and a second peripheral edge extending around the perimeter of the second transparent substrate, the first substrate having a larger length and width than the second substrate, wherein the first and second transparent substrates are arranged such that the second and third surfaces are substantially parallel and the larger first transparent substrate extends beyond the second peripheral edge of the second substrate along all four sides of the substrates; a second transparent electrically conductive layer disposed on the third surface; an electro-optic medium disposed between the first and second electrically conductive layers; a first buss disposed on the first surface along the first tabs while extending within the first notches to electrically contact the second transparent electrically conductive layer without electrically contacting the first transparent electrically conductive layer; and a second buss disposed to electrically contact the first transparent electrically conductive layer along the portion of the first substrate that extends beyond the second peripheral edge of the second substrate without electrically contacting the second transparent electrically conductive layer.

[0005] It is another aspect of the present disclosure to provide an electro-optic element including: a first transparent substrate having a first surface, a second surface opposite the first surface, and a first peripheral edge extending around the perimeter of the first transparent substrate, wherein the first transparent substrate has a plurality of first holes spaced around a perimeter of the first transparent substrate; a first transparent electrically conductive layer disposed on the second surface; a second transparent substrate having a third surface, a fourth surface opposite the third surface, and a second peripheral edge extending around the perimeter of the second transparent substrate,wherein the second transparent substrate has a plurality of second holes spaced around a perimeter of the second transparent substrate, wherein the first and second transparent substrates are arranged such that the second and third surfaces are substantially parallel with the first holes offset from the second holes; a second transparent electrically conductive layer disposed on the third surface; an electro-optic medium disposed between the first and second electrically conductive layers; a first buss disposed on the first surface extending within the first holes to be electrically coupled to the second transparent electrically conductive layer without electrically contacting the first transparent electrically conductive layer; and a second buss disposed on the fourth surface extending within the second holes to be electrically coupled to the first transparent electrically conductive layer without electrically contacting the second transparent electrically conductive layer.

[0006] These and other features, advantages, and objects of the present disclosure will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0008] FIG. 1A is a perspective view of an automobile that incorporates at least one electro-optic element, in accordance with an aspect of the present disclosure;

[0009] FIG. IB is a perspective view of an airplane that incorporates at least one electrooptic element, in accordance with an aspect of the present disclosure;

[0010] FIG. 1C is a perspective view of a building that incorporates at least one electrooptic element, in accordance with an aspect of the present disclosure;

[0011] FIG. 2A is a front view of a first substrate used in an electro-optic element, in accordance with an aspect of the present disclosure;

[0012] FIG. 2B is a front view of a second substrate used in the electro-optic element;

[0013] FIG. 3 is a front view of a partially assembled electro-optic element;

[0014] FIG. 4 is a front view of an assembled electro-optic element;

[0015] FIG. 5 is a side view of the electro-optic element shown in FIG. 4;

[0016] FIG. 6 is a partial front view of a partially assembled electro-optic element according to one variation;

[0017] FIG. 7 is a partial back view of an assembled electro-optic element according to another variation;

[0018] FIG. 8 is a partial front view of a partially assembled electro-optic element according to another variation;

[0019] FIG. 9 is a front view of a partially assembled electro-optic element according to another variation; and

[0020] FIG. 10 is a front view of an assembled electro-optic element according to the variation shown in FIG. 9.DETAILED DESCRIPTION

[0021] The present illustrated embodiments reside primarily in combinations of method steps and apparatus components related to an electro-optic element. Accordingly, the apparatus components and method steps have been represented, where appropriate, by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Further, like numerals in the description and drawings represent like elements.

[0022] In this document, relational terms, such as first and second, top and bottom, and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0023] Large area devices (LADs) such as windows and sunroofs for land vehicles, windows for airplanes, or architectural windows for buildings have incorporated electrooptic elements that may be selectively darkened to enhance privacy and to reduce the brightness of light passing therethrough. Some LADs have been made in the past using asolution-phase electro-chromic material between two glass substrates having indium tin oxide (ITO) coatings. These LADs were relatively thick having a cell spacing between the substrates of about 420 pm. With this large a cell spacing, busses made of silver ink or conductive tape were provided along one or more perimeters on the inner surfaces of the each of coated glass substrates with a nonconductive seal provided therebetween and conductive tabs extending outward for electrical connection to the busses. The busses could be made relatively thick given the cell spacing of the device.

[0024] In a move to make LADs thinner and lighter, thinner cell spacings have been proposed. Such a device may have a cell spacing of about 25 to 100 pm, which is much smaller than the prior device with its 420 pm cell spacing. However, in the proposed device, polymer substrates may be used and ITO layers on the polymer substrates exhibit a noticeably higher sheet resistance (about 10-20 ohm / sq.) than the same ITO layers when on glass substrates (as low as about 1 ohm / sq.). Further, the cell spacing is so much smaller that the busses are too thick to fit within the cell spacing. Although some LADs address this by offsetting the substrates and then applying the bus to the offset side(s), this approach does not allow a buss to contact the electrode layers around their full perimeter, which leads to reduced performance. The present disclosure addresses these technical problems and provides for improved electro-optic elements that are thinner, exhibit improved response times, more uniform coloration, and are capable of being more easily manufactured at reduced cost.

[0025] As discussed further below, the present disclosure pertains to an electro-optic element 10. With reference now to FIGS. 1A-1C, the electro-optic element 10 may be incorporated with one or more structures 36A-36C. For example, FIG. 1A illustrates a vehicle 36A employing the electro-optic element 10. All or some components of the electro-optic element 10 may be located within, or at least partially form, a vehicle mirror 38 or a vehicle window or sunroof 40. The vehicle 36A may include a commercial vehicle, an emergency vehicle, a residential vehicle, a train, or the like. FIG. IB illustrates an airplane 36B employing the electro-optic element 10. The electro-optic element 10 may be located within, or at least partially form, an airplane window 42. FIG. 1C illustrates a building 36C employing the electro-optic element 10. The electro-optic element 10 may be located within, or at least partially form, a building window 44.Generally speaking, the electro-optic element 10 may be incorporated into any environment wherein changing transmittance and / or reflectivity is beneficial.

[0026] As shown in FIGS. 2A and 3-5, the electro-optic element 10 may include a first substrate 12 having a first surface 12a, a second surface 12b opposite the first surface 12a, and a first peripheral edge 12c extending around the perimeter of the first substrate 12, wherein the first peripheral edge 12c is crenulated so as to have alternating first tabs 16 and first notches 18. As shown in FIGS. 2B and 3-5, the electro-optic element 10 may further include a second substrate 14 having a third surface 14a, a fourth surface 14b opposite the third surface 14a, and a second peripheral edge 14c extending around the perimeter of the second substrate 14, wherein the second peripheral edge 14c is crenulated so as to have alternating second tabs 20 and second notches 22. As shown in FIGS. 3 and 5, the first and second substrates 12 and 14 are arranged such that the second and third surfaces 12b and 14a are substantially parallel with the first tabs 16 aligned with the second notches 22 and the second tabs 20 aligned with the first notches 18.

[0027] FIG. 4 shows a front view of an assembled electro-optic element 10. FIG. 5 shows a side view of the assembled electro-optic element 10. As shown in FIG. 5, a first transparent electrically conductive layer 24 is disposed on the second surface 12b and a second transparent electrically conductive layer 26 is disposed on the third surface 14a. An electro-optic medium 30 is disposed between the first and second electrically conductive layers 24 and 26.

[0028] As shown in FIGS. 4 and 5, a first buss 32 is disposed on the first surface 12a along the first tabs 16 while extending within the first notches 18 so as to electrically contact the second electrically conductive layer 26 on the second tabs 20 without electrically contacting the first electrically conductive layer 24. Similarly, a second buss 34 is disposed on the fourth surface 14b along the second tabs 20 while extending within the second notches 22 so as to electrically contact the first electrically conductive layer 24 on the first tabs 16 without electrically contacting the second electrically conductive layer 26.

[0029] It should be noted that the figures, particularly FIG. 5, are not to scale or in the proper proportion. The proportions shown are for purposes of explanation only. As explained further below, the first and second substrates 12 and 14 are typically muchthinner (on the order of 125 each) with a thinner cell spacing (on the order of 50-200 pm each or about 25 pm) with a thinner cell spacing (on the order of about 25 pm). Thus, the first and second busses 32 and 34 would not have to deflect into the notches 18 and 22 nearly as much as is illustrated.

[0030] The first and second busses 32 and 34 may be a conductive tape or other preformed conductive material or may be a conductive material that is formed as it is applied to the outer surfaces 12a and 14b of the substrates 12 and 14, respectively, such as a silver ink. An example of a conductive buss tape is Adhesives Research ARcare 90038. The conductive tape may has a width of 2 to 3 mm for example.

[0031] In addition, the first and second tabs 16 and 20 and the corresponding notches 18 and 22 may extend around the entire perimeter of the first and second substrates 12 and 14 and the first and second busses 32 and 34 may also extend around the entire perimeter of the first and second substrates 12 and 14 so as to contact inside surfaces of all of the tabs 16 and 20. By providing electrical connections to the busses intermittently around the entire perimeter of the element 10, the negative impact of a higher sheet resistance of the electrically conductive layers 24 and 26 over a large area may be mitigated. Moreover, the initial in-rush current is higher and the element 10 colors both faster, and more uniformly. Although the tabs and notches are described as extending around the entire perimeter of the substrates, there may be portions of the perimeters that do not include such tabs and notches such as any significantly curved portions.

[0032] The first and second transparent substrates 12 and 14 may be made of a polymer such as polyethylene terephthalate (PET), one or more plastics, or multi-plastic stacks, for example, and may have a thickness of about 125 pm. Alternatively, the transparent substrates 12 and 14 may be made of glass or a hybrid glass / polymer material. The first transparent electrically conductive layer 24 and the second transparent electrically conductive layer 26 may be formed by electrically conductive transparent materials, including, but not limited to, a transparent conducting film (e.g., indium tin oxide (ITO), F:SnO2, ZnO, IZO), insulator-metal-insulator ("IMI") structures, carbon (graphene and / or graphite) and / or a conductive metal mesh (e.g., nanowires).

[0033] The electro-optic medium 30 may be a solid-state thin film electro-optic medium or may be a solution-phase electro-optic medium. Although a seal would be included for a solution phase medium, such a seal is optional for a thin film electro-optic medium.Seals offer benefits of preserving the chemistry through assembly processes (from water, mainly). They provide a potential long-term benefit of providing barrier between the chemistry and laminate (PVB, TPU, etc.). A film seal could also be an electrical isolation between cathodic and anodic substrates (in some designs). The thin film may include cathodic materials, anodic materials, and electrolyte materials.

[0034] The busses 32 and 34 may be directly connected to the transparent conductive layers 24 and 26 or alternatively electrically coupled to the transparent conductive layers 24 and 26 indirectly through the anodic or cathodic species.

[0035] The tabs 16 and 20 and corresponding notches 18 and 22 need not be the same size. For example, as shown in FIG. 6, the notches 18 and 22 may be wider than the tabs 16 and 20 so that there are visible gaps between the tabs 16 and 20 when viewing from the front or back of the element 10. These gaps may be between 0.5 mm and 5 mm and may be 3 mm. These gaps may reduce the risk of shorting as a result of inadvertent contact between the first buss 32 and the first electrode 24 or between the second buss 34 and the second electrode 26. Alternatively, the tabs 16 and 20 may be wider than the notches 18 and 22 so that the tabs 16 and 20 overlap each other. The width of tabs 16 and 20 may vary over the length of one side or on different sides. Further, the tabs 16 and 20 for one substrate may be wider than the tabs 16 and 20 for the other substrate. The number of the tabs 16 and 20 may vary from one side of the substrates 12 and 14 to the other. Further still, the tabs 16 and 20 need not be centered relative to an associated notch 18 and 22. Also, the tabs and notches need not have a rectangular shape, but may have any shape such as curves as shown in FIG. 7, and different combinations of shapes may be used on one substrate or comparing one substrate to the other. By curving the notches and tabs, cutting the substrates is simplified and the element may be more bended without buckling. An electrically insulating seal may optionally be provided between the tabs 16 and 20 to prevent electrical shorting.

[0036] The length of the tabs 16 and 20 and the depth of the notches 18 and 22 as well as the width of the busses 32 and 34 may be varied to provide larger contact areas. The busses 32 and 34 may have a width of 2 to 3 mm, for example. Further, the length of first tabs 16 may be shorter or longer than second tabs 20. In this way, if the first tabs 16 are longer than the second tabs 20 as shown in FIG. 8, the second buss 34 could make contact to the first transparent electrically conductive layer 24 on the first tabs 16directly without touching the fourth surface 14b. In this case, the first buss 32 would be further inboard than the second buss 34. With this buss configuration, the second substrate 14 may not need to have notches 22 and tabs 20 around the second peripheral edge 14c.As another alternative shown in FIGS. 9 and 10, the notches 18 and 22 could be replaced with holes 18a and 22a on one or both of the substrates 12 and 14 where one or both of the busses 32 and 34 make electrical contact with the respective transparent electrically conductive layers 24 and 26 through the holes 18a and 22a. More specifically, the first transparent substrate 12 has a plurality of first holes 18a spaced around a perimeter of the first transparent substrate 12 and the second transparent substrate 14 has a plurality of second holes 22a spaced around a perimeter of the second transparent substrate 14, wherein the first and second transparent substrates 12 and 14 are arranged such that the first holes 18a are offset from the second holes 22a as shown in FIG. 9. As shown in FIG. 10, the first buss 32 disposed on the first surface 12a extends within the first holes 18a to be electrically coupled to the second transparent electrically conductive layer 26 without electrically contacting the first transparent electrically conductive layer 24. The second buss 34 disposed on the fourth surface 14b extends within the second holes 22a to be electrically coupled to the first transparent electrically conductive layer 24 without electrically contacting the second transparent electrically conductive layer 26.

[0037] By adjusting the relative sizes / numbers of the tabs 16 and 20, one may balance the coloring and clearing timing or change timing ratio to get different coloring or clearing effects such as irising or a curtain effect where the device clears or colors from left or right or top or bottom. Furthermore, the frequency of the crenelations may be changed with changes in curvature of the substrates.

[0038] The electro-optic medium 30 may be selected such that it exhibits a memory to retain a colored state or a non-colored state without application of a voltage.

[0039] In this document, relational terms, such as "first," "second," and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0040] As used herein, the term "and / or," when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination oftwo or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and / or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

[0041] For purposes of this disclosure, the term "associated" generally means the joining of two components (electrical or mechanical) directly or indirectly to one another. Such joining may be stationary in nature or movable in nature. Such joining may be achieved with the two components (electrical or mechanical) and any additional intermediate members being integrally formed as a single unitary body with one another or with the two components. Such joining may be permanent in nature or may be removable or releasable in nature unless otherwise stated.

[0042] The term "substantially," and variations thereof, will be understood by persons of ordinary skill in the art as describing a feature that is equal or approximately equal to a value or description. For example, a "substantially planar" surface is intended to denote a surface that is planar or approximately planar. Moreover, "substantially" is intended to denote that two values are equal or approximately equal. If there are uses of the term which are not clear to persons of ordinary skill in the art, given the context in which it is used, "substantially" may denote values within 10% of each other, such as within 5% of each other, or within 2% of each other.

[0043] The term "transparent" is applied in the relative sense. "Transparent" refers to an optical element or material that is substantially transmissive of wavelengths in question and thus generally allows light at such wavelengths to pass therethrough. The wavelengths in question will vary based on the context. However, in the event the wavelengths in question is not readily apparent, the wavelengths in question shall generally refer to visible light.

[0044] It should be appreciated by those skilled in the art that the above-described components may be combined in additional or alternative ways not explicitly described herein. Modifications of the various implementations of the disclosure will occur to those skilled in the art and to those who apply the teachings of the disclosure. Therefore, it is understood that the embodiments shown in the drawings and described above are merely for illustrative purposes and not intended to limit the scope of thedisclosure, which is defined by the following claims as interpreted according to the principles of patent law, including the doctrine of equivalents.

Claims

CLAIMSWhat is claimed is:

1. An electro-optic element comprising: a first transparent substrate having a first surface, a second surface opposite the first surface, and a first peripheral edge extending around the perimeter of the first transparent substrate, wherein the first peripheral edge is crenulated so as to have alternating first tabs and first notches; a first transparent electrically conductive layer disposed on the second surface; a second transparent substrate having a third surface, a fourth surface opposite the third surface, and a second peripheral edge extending around the perimeter of the second transparent substrate, wherein the second peripheral edge is crenulated so as to have alternating second tabs and second notches, wherein the first and second transparent substrates are arranged such that the second and third surfaces are substantially parallel with the first tabs aligned with the second notches and the second tabs aligned with the first notches; a second transparent electrically conductive layer disposed on the third surface; an electro-optic medium disposed between the first and second electrically conductive layers; a first buss disposed on the first surface along the first tabs while extending within the first notches so as to be electrically coupled to the second transparent electrically conductive layer on the second tabs without electrically contacting the first transparent electrically conductive layer; and a second buss disposed to be electrically coupled to the first transparent electrically conductive layer on the first tabs without electrically contacting the second transparent electrically conductive layer.

2. The electro-optic element of claim 1, wherein the first and second busses extend around the entire perimeter of the respective first and second transparent substrates.

3. The electro-optic element of any one of claims 1 and 2, wherein the electro-optic medium is a thin film electro-optic medium.

4. The electro-optic element of any one of claims 1-3, wherein the first and second transparent substrates comprise a polymer.

5. The electro-optic element of any one of claims 1-4, wherein the second buss is disposed on the fourth surface along the second tabs while extending within the second notches.

6. The electro-optic element of any one of claims 1-5, wherein the first buss is in direct contact with the second transparent electrically conductive layer and the second buss is in direct contact with the first transparent electrically conductive layer.

7. The electro-optic element of any one of claims 1-6, wherein the first and second notches are wider than the first and second tabs to form a gap between the first and second tabs.

8. The electro-optic element of any one of claims 1-7, wherein the gap is between 0.5 mm and 5 mm.

9. The electro-optic element of any one of claims 1-8, wherein the first and second tabs and the first and second notches have curved edges.

10. The electro-optic element of any one of claims 1-4 and 6-9, wherein the first substrate having a larger length and width than the second substrate, wherein the first and second transparent substrates are arranged such that the larger first transparent substrate extends beyond the second peripheral edge of the second substrate along all four sides of the substrates, and wherein the second buss electrically contacts the first transparent electrically conductive layer along the portion of the first substrate that extends beyond the second peripheral edge of the second substrate.

11. An electro-optic element comprising: a first transparent substrate having a first surface, a second surface opposite the first surface, and a first peripheral edge extending around the perimeter of the first transparent substrate, wherein the first peripheral edge is crenulated to have alternating first tabs and first notches; a first transparent electrically conductive layer disposed on the second surface; a second transparent substrate having a third surface, a fourth surface opposite the third surface, and a second peripheral edge extending around the perimeter of the second transparent substrate, the first substrate having a larger length and width than the second substrate, wherein the first and second transparent substrates are arranged such that the second and third surfaces are substantially parallel and the larger first transparent substrate extends beyond the second peripheral edge of the second substrate along all four sides of the substrates; a second transparent electrically conductive layer disposed on the third surface; an electro-optic medium disposed between the first and second electrically conductive layers; a first buss disposed on the first surface along the first tabs while extending within the first notches to electrically contact the second transparent electrically conductive layer without electrically contacting the first transparent electrically conductive layer; and a second buss disposed to electrically contact the first transparent electrically conductive layer along the portion of the first substrate that extends beyond the second peripheral edge of the second substrate without electrically contacting the second transparent electrically conductive layer.

12. The electro-optic element of claim 11, wherein the second peripheral edge is crenulated to have alternating second tabs and second notches, wherein the first and second transparent substrates are arranged such that the second and third surfaces are substantially parallel with the first tabs aligned with the second notches and the second tabs aligned with the first notches.

13. The electro-optic element of any one of claims 11 and 12, wherein the first and second notches are wider than the first and second tabs to form a gap between the first and second tabs.

14. The electro-optic element of any one of claims 11-13, wherein the gap is between 0.5 mm and 5 mm.

15. The electro-optic element of any one of claims 11-14, wherein the first and second busses extend around the entire perimeter of the respective first and second transparent substrates.

16. The electro-optic element of any one of claims 11-15, wherein the electro-optic medium is a thin film electro-optic medium.

17. The electro-optic element of any one of claims 11-16, wherein the first and second transparent substrates comprise a polymer.

18. The electro-optic element of any one of claims 11-17, wherein the first buss is in direct contact with the second transparent electrically conductive layer and the second buss is in direct contact with the first transparent electrically conductive layer.

19. An electro-optic element comprising: a first transparent substrate having a first surface, a second surface opposite the first surface, and a first peripheral edge extending around the perimeter of the first transparent substrate, wherein the first transparent substrate has a plurality of first holes spaced around a perimeter of the first transparent substrate; a first transparent electrically conductive layer disposed on the second surface; a second transparent substrate having a third surface, a fourth surface opposite the third surface, and a second peripheral edge extending around the perimeter of the second transparent substrate, wherein the second transparent substrate has a plurality of second holes spaced around a perimeter of the second transparent substrate, whereinthe first and second transparent substrates are arranged such that the second and third surfaces are substantially parallel with the first holes offset from the second holes; a second transparent electrically conductive layer disposed on the third surface; an electro-optic medium disposed between the first and second electrically conductive layers; a first buss disposed on the first surface extending within the first holes to be electrically coupled to the second transparent electrically conductive layer without electrically contacting the first transparent electrically conductive layer; and a second buss disposed on the fourth surface extending within the second holes to be electrically coupled to the first transparent electrically conductive layer without electrically contacting the second transparent electrically conductive layer.

20. The electro-optic element of claim 19, wherein the first and second busses extend around the entire perimeter of the respective first and second transparent substrates.

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