The present invention generally relates to electro-optic (EO) devices and apparatus incorporating such devices. In particular, the invention relates to electro-optic devices used in vehicular rearview mirror elements and/or architectural windows.
Electro-optic rearview mirror elements are becoming more common in vehicular applications with regard to both inside and outside rearview mirrors and mirror assemblies, whether on the driver's or the passenger's side. Such electro-optic rearview mirrors are automatically controlled to vary the reflectivity of the mirror in response to rearward and forward aimed light sensors so as to reduce the glare of headlamps in the image reflected to the driver's eyes. Typical electro-optic elements, when incorporated in vehicular rearview mirror assemblies, will have an effective field of view (as defined by relevant laws, codes and specifications) that is less than the area defined by the perimeter of the element itself. Often, the effective field of view of the element is limited, at least in part, by the construction of the element itself and/or an associated bezel.
Typically, a vehicular rearview assembly (for example, an autodimming assembly such as, generally, EO mirror assembly and, in particular, an electrochromic, EC, assembly, or an assembly including a prismatic element) includes a mirror element that is at least partially encased in a casing or housing element, sometimes with a bezel portion of the housing element that encompasses at least a portion of the edge surface of the mirror element and that mechanically cooperates (via snapping elements or other integration mechanism) with the remaining portion of the housing element. Typically, either the mirror element or the assembly itself is spatially (for example, angularly) alterable by the driver (for example, via a pivot assembly) to adjust a rearward field of view associated with the rearview assembly.
Various attempts have been made to provide a mirror element having an effective field of view substantially equal to the area defined by its perimeter. As shown in FIG. 1, depicting a cross-sectional portion of a typical rearview assembly employing an EC element, the subassembly 100 includes an EC mirror element 110, a bezel 112, and a carrier plate 117. The subassembly may further include gaskets 120 and 122 that are placed on either side of the EC element 110 to form a secondary seal around the periphery of the element 110. The EC element 110 includes a front substantially transparent element or substrate 130 typically formed of glass and having a front surface 130a and a rear surface 130b. The EC element 110 further includes a rear element 140, which is spaced slightly apart from the element 130. A seal 146 is formed between elements 130 and 140 about their periphery so as to define a sealed chamber 147 therebetween, in which an EC medium is provided. As known in the art, elements 130 and 140 preferably have electrically conductive layers (serving as electrodes, not shown) on the surfaces facing the chamber such that an electrical potential may be applied across the EC medium. These electrodes are electrically isolated from one another and are separately coupled to a power source (not shown) by means of corresponding bus connectors (connector 148b is shown in a specific implementation, as an electrically-conducting clip). To facilitate attachment of bus connectors to corresponding electrically-conducting layers, elements 130 and 140 are typically mutually offset so that one bus connector may be secured along a bottom edge of one of the elements and another bus connector may be secured to the top edge of the other element. The bus connectors (such as the connector 148b) may be spring clips (similar to those disclosed in commonly-assigned U.S. Pat. Nos. 6,064,509 and 6,062,920) and are configured to ensure that they remain physically and electrically coupled to the electrode layers on the inward-facing surfaces of elements 130 and 140. Alternatively, the bus connectors may include an electrically-conductive member such as a thin-film or foil that electrically extends a corresponding conductive layer to the back of the assembly over an edge surface of at least one of the elements 130, 140 (as discussed, for example, in commonly-assigned U.S. patent application Ser. Nos. 12/505,458, 12/563,917). In a specific implementation, such electrical extension may include a portion that wraps around an edge of a corresponding substrate. Once the EC element 110 has been manufactured and bus connectors have been configures, then the mirror subassembly 100 may be formed. As shown in FIG. 1, a bezel 112, the function of which is to mechanically support the element retained by the bezel, may include a front lip 151 extending over a portion of the front surface 130a of the front element 130. While the width D1 of such lip may vary, it typically extends over a sufficient portion such as 5 mm, for example, of the front surface 130a to obscure a person's view of the seal 146 and protect the seal 146 from possible degradation caused by ambient UV light.
Prior to inserting the electrochromic mirror element 110 in the bezel 115, an optional front gasket 120 may be provided behind the front lip 151 so as to be pressed between the front surface 130a of the front element 130 and the inner surface of the front lip 151 of bezel 112. The mirror element 110 is then placed in bezel 112 and an optional rear gasket 122 may be provided along the periphery of the back surface of element 140. In lieu of, or in addition to front and/or rear gaskets 120, 122 the bezel/mirror interface area may be filled or potted with a sealing material such as urethane, silicone, or epoxy. A carrier plate 117, which is typically formed of an engineering grade rigid plastic or a similar material as used for bezel 112, is then pressed against the rear surface of element 140 with the gasket 122 compressed therebetween. A plurality of tabs (not shown) may be formed inside of the bezel such that carrier plate 117 is snapped in place so as to secure mirror element 110 within the bezel. The carrier plate 117 is typically used to mount the mirror subassembly within an exterior mirror housing. More specifically, a specific positioner (not shown) may also be mounted within the mirror housing and mechanically coupled to the carrier plate 117 for enabling remote adjustment of the position of the mirror subassembly within the housing. Various embodiments with reduced lip of the bezel has been also discussed in prior art.
While the above-described structures are readily manufacturable, various styling concerns have arisen that often require not only elimination of a conventional bezel but addressing various structural and functional problems generated by such change.