US 5,724,187 · Granted 1998-03-03
The Smart Mirror Patent That Dims Itself in Headlights
Imagine a car mirror that automatically darkens when bright headlights hit it at night, then goes clear again when the light fades. This patent covers the chemistry and structure that makes mirrors change tint electronically without any moving parts — just a thin special film that responds to electrical signals.
The plain-English version
What it protects
The claim covers electrochromic mirrors built with a solid electrochromic film combined with an electrolyte containing redox reaction promoters and alkali ions or protons. What's protected here is the specific material composition and layering that allows the mirror to change its light-reflecting properties when electric current passes through it. Anyone making an auto-dimming mirror using this same electrochemical approach would need permission from the patent holder.
Why it matters
Auto-dimming mirrors became a premium safety feature in vehicles, reducing glare and eye strain for drivers during nighttime driving. Donnelly Corporation, a major automotive supplier, used this patent to establish a foothold in the electrochromic mirror market, which became standard equipment on many high-end vehicles. The patent protected their investment in developing a reliable, electronically controlled mirror system that required no mechanical moving parts.
Real-world use
Every luxury car with an auto-dimming rearview mirror uses electrochromic technology to prevent blinding glare from headlights behind you on the highway.
Original USPTO abstract
The present invention relates to electrochromic mirrors and devices whose electrochromic element is composed of an electrochromic solid film and an electrolyte comprising redox reaction promoters and alkali ions and/or protons.
Patent details
- Publication number
- US 5,724,187
- Filing date
- 1995-04-27
- Grant date
- 1998-03-03
- Assignee
- Donnelly Corporation
- Inventor(s)
- VARAPRASAD; DESARAJU V., MCCABE; IAN A., HABIBI; HAMID, LYNAM; NIALL R., ZHAO; MINGTANG, DORNAN; CRAIG A.
- CPC class
- B60R1/088
Want to file your own patent?
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