US 7,255,451 · Granted 2007-08-14
The Smart Mirror That Dims Itself—Without Moving
This patent describes a special mirror for cars that can automatically get darker or lighter by applying electricity to thin coatings sandwiched between two glass layers. Instead of a mechanical shade flipping down, you get a smooth glass surface that changes its reflectiveness on demand—like sunglasses that adjust themselves.
The plain-English version
What it protects
The claim covers a reflective mirror assembly made of two glass substrates with special conductive coatings on multiple surfaces, where those coatings wrap around the edges to maintain electrical connection. What's protected here is the specific arrangement of how these conductive layers are positioned and connected so that applying voltage across them changes how much light the mirror reflects back.
Why it matters
This patent represents a core building block in electrochromic mirror technology, which eliminates the need for mechanical anti-glare systems in vehicles. By controlling reflectance electronically, manufacturers can improve safety and comfort for drivers and passengers without adding moving parts that wear out or fail. The design's clever edge-wrapping technique solves a practical problem: maintaining reliable electrical contact between multiple coated surfaces in a durable, manufacturable way.
Real-world use
When a car's headlight sensor detects bright lights from oncoming traffic at night, the rearview mirror automatically darkens to reduce glare—no manual adjustment needed.
Original USPTO abstract
A reflective element assembly for a variable reflectance vehicular mirror includes a front substrate having a transparent conductive coating disposed on a second surface, and a rear substrate having a third surface conductive coating disposed on its third surface and preferably, a fourth surface conductive coating disposed on its fourth surface. At least a portion of the third surface conductive coating may wrap around an edge portion of the rear substrate and at least a portion of the fourth surface conductive coating may wrap around at least a second portion of the perimeter edge so as to establish electrical continuity between the fourth surface conductive coating on the fourth surface and the third surface conductive coating on the third surface. The rear substrate may have a smaller dimension than the front substrate so as to provide an overhang region, preferably at the wraparound region.
Patent details
- Publication number
- US 7,255,451
- Filing date
- 2004-12-23
- Grant date
- 2007-08-14
- Assignee
- Donnelly Corporation
- Inventor(s)
- MCCABE IAN A., HABIBI HAMID, LYNAM NIALL R., BAREMAN DONALD L.
- CPC class
- B60R1/1207
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