US 7,855,755 · Granted 2010-12-21
The Mirror That Became a Dashboard: Donnelly's Dual-Purpose Display
Imagine your car's rearview mirror that's also a screen — it can show you directions, camera feeds, or warnings while still letting you see what's behind you. The trick is using special glass that's see-through enough to work as a mirror but transparent enough to let a hidden display shine through from behind.
The plain-English version
What it protects
The claim covers a rearview mirror assembly where a special partially-transparent reflective surface acts as both a mirror and a window into a display hidden behind it. What's protected here is the combination of that transflective element (which bounces back at least 60% of light so you see a reflection, but lets through 10% or more so a display can glow through) paired with LED light sources arranged behind it and a heat-management system that pulls warmth away from those LEDs without being visible from outside the mirror.
Why it matters
This patent tackles a real engineering challenge: how to pack a functional display into your rearview mirror without turning it into a glowing brick or compromising its ability to show you what's actually behind your car. Donnelly's approach — combining optical trickery with thermal management — became a template for modern heads-up displays and camera-mirror systems that carmakers now use as standard features to improve safety and navigation without adding clutter to the dashboard.
Real-world use
When your new car shows a backup camera feed or lane-change warnings inside the rearview mirror itself, you're looking at the evolution of this patent's core idea.
Original USPTO abstract
A video mirror system for a vehicle comprising an interior rearview mirror assembly having a transflective electro-optic reflective element that transmits at least about ten percent of visible light incident thereon and reflects at least about sixty percent of visible light incident thereon. A display module is disposed at a rear of the transflective electro-optic reflective element and comprises a plurality of individual light sources. A thermally conductive element may be in substantial thermal contact with the display module and is exposed at a rear casing portion of the mirror assembly so as to draw heat generated by the display module away from the display module and to the exterior of the interior rearview mirror assembly. The exposure of the thermally conductive element at the rear casing portion may be substantially not discernible to a viewer viewing the rear casing portion of the interior rearview mirror assembly.
Patent details
- Publication number
- US 7,855,755
- Filing date
- 2006-10-31
- Grant date
- 2010-12-21
- Assignee
- Donnelly Corporation
- Inventor(s)
- WELLER ANDREW D., LARSON MARK L., MCCABE IAN A., LYNAM NIALL R., BLANK RODNEY K., MCCAW JOSEPH P., UKEN JOHN T.
- CPC class
- G02F1/133308
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