US 5,239,405 · Granted 1993-08-24
How Donnelly's Electrochromic Patent Powers Smart-Tinting Glass
Imagine glass that darkens or lightens on command when you flip a switch. This patent describes special chemical solutions that change color way faster and more evenly than older versions when you apply electricity to them. It's the foundation for auto-dimming mirrors and smart windows that respond instantly.
The plain-English version
What it protects
The claim covers electrochromic solutions made by pre-treating one chemical compound with a redox agent before mixing it with another electrochromic compound. What's protected here is both the chemical formulation itself and the specific preparation process that creates superior speed, intensity, and uniformity of color change when electrical voltage is applied. Anyone manufacturing or selling electrochromic devices using this pre-treatment method would infringe without a license.
Why it matters
Electrochromic technology enables auto-dimming rear-view mirrors, smart windows, and display devices that respond to light and heat. Donnelly Corporation, a major automotive supplier, used this patent to dominate the electrochromic mirror market. By solving the speed and uniformity problem that plagued earlier solutions, this patent made the technology commercially viable for mass production in vehicles and buildings.
Real-world use
When you sit in a car with an auto-dimming rear-view mirror that adjusts itself in bright sunlight, the electrochromic chemistry inside is working because of innovations like this patent.
Original USPTO abstract
The present invention relates to electrochromic solutions and devices manufactured therefrom. More precisely, the invention relates to electrochemichromic solutions, and those devices manufactured with the same, that demonstrate superior responsiveness to those solutions known heretofore when an applied potential is introduced thereto. That is, the responsiveness observed in terms of solution coloring is of a greater rapidity, intensity and uniformity than those electrochemichromic solutions of the prior art. Preparation of these solutions involve the novel process of pre-treating at least one of the electrochemichromic compounds with a redox agent prior to placing it in contact with the other electrochemichromic compound. Moreover, the present invention relates to methods of preparing such novel solutions and processes for using these solutions to provide devices that exhibit and benefit from the aforementioned superior characteristics.
Patent details
- Publication number
- US 5,239,405
- Filing date
- 1991-09-06
- Grant date
- 1993-08-24
- Assignee
- Donnelly Corporation
- Inventor(s)
- VARAPRASAD; DESARAJU V., LOOMAN; STEVEN D., ZHAO; MINGTANG, HABIBI; HAMID R., LYNAM; NIALL R.
- CPC class
- C25B11/00
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