US 4,882,565 · Granted 1989-11-21
The Hidden Message Mirror That Changed Car Dashboards Forever
Imagine a rearview mirror that could display useful information—like the time or temperature—without getting in the way of actually seeing behind you. This patent describes a mirror with tiny laser-etched lines that only light up when you flip a switch, staying invisible when the light is off so you can drive safely.
The plain-English version
What it protects
The claim covers a rearview mirror assembly where information is encoded as narrow deletion lines etched into the reflective coating using laser marking. A light source positioned behind the mirror illuminates these lines to make them visible. What's protected here is the specific combination of the laser-marked indicia, the backlighting approach, and the property that the lines remain virtually invisible to the naked eye when the light is off—preventing distraction during normal driving.
Why it matters
This patent represents an early leap toward smart vehicle interiors. By embedding information directly into a mirror component that drivers already look at frequently, it solved a real problem: how to add digital information to cars without cluttering the dashboard or creating safety hazards. Donnelly Corporation, a major automotive supplier, secured this technology during the late 1980s when in-cabin displays were still relatively simple, positioning them ahead of competitors in the integrated mirror market.
Real-world use
Modern rearview mirrors with built-in compasses, temperature displays, and turn-signal indicators owe their basic design to this patent—every time a driver glances at a mirror to see both the road behind and a small data readout, that's the principle at work.
Original USPTO abstract
A rearview mirror assembly for vehicles which displays information useful to the driver/viewer when viewing the mirror assembly. Indicia are formed by narrow deletion lines, preferably using computer controlled laser marking apparatus, in a reflective coating on a mirror element of the assembly. A light source, which may be a light emitting diode, an incandescent bulb or another type source, is positioned behind the mirror element to illuminate the indicia for distinct, clear, precise visibility by the driver/viewer. The lines of the deletion area are sufficiently narrow as to be generally unnoticeable to the unaided viewer's eyes when a rear vision image is reflected by the reflecting surface and the light source is unlit thereby preventing interference with normal driving use of the mirror assembly. The light source may be used to simultaneously illuminate portions of the vehicle as well as the deletion area indicia.
Patent details
- Publication number
- US 4,882,565
- Filing date
- 1988-03-02
- Grant date
- 1989-11-21
- Assignee
- Donnelly Corporation
- Inventor(s)
- GALLMEYER; WILLIAM W.
- CPC class
- B60R1/12
Want to file your own patent?
If you're dreaming up a new automotive feature or gadget, check our free scanner to see what's already claimed in your space before you pitch it to a manufacturer.
Free patentability scan