US 7,559,672 · Granted 2009-07-14
The LED Lens That Makes Grocery Store Shelves Glow Evenly
Imagine trying to light up a grocery store shelf with an LED so the cheese looks as bright as the deli meat—no dark spots, no hot spots. This patent describes a flat, ridged lens that spreads LED light perfectly even across long, narrow spaces like refrigerator display cases. It uses math to figure out exactly how to tilt each tiny ridge so light lands where it's needed.
The plain-English version
What it protects
The claim covers a Fresnel lens design for linear LED lighting that uses a specific computational method to arrange and adjust tiny mirror-like facets. What's protected is the combination of: (1) starting with a flux-assignment calculation, (2) measuring how light actually spreads from each individual facet, and (3) fine-tuning facet angles to achieve uniform illumination across a long, narrow zone. The lens is thin enough to be manufactured by extrusion, making it economical to mass-produce.
Why it matters
This patent solves a real commercial problem: uneven lighting in refrigerated food displays kills product appeal and wastes energy. Before this design, retailers either accepted bad lighting or paid for expensive, thick optical solutions. By combining calculation with real-world light measurement and correction, this lens delivers professional-quality even illumination at a fraction of the cost. The ability to extrude it means factories can mass-produce it efficiently, making it practical for thousands of store fixtures.
Real-world use
The next time you're standing in front of a grocery store refrigerator case and notice the vegetables, meats, and cheeses are all lit up evenly without shadows or glare, you're likely looking at a lens based on this design principle.
Original USPTO abstract
A linear Fresnel lens for LED illumination is configured initially by using a meridional flux-assignment method and is then corrected by assessing the three-dimensional flux distribution of individual facets. The facet angles are slightly altered as required to produce uniformity. A variety of specialized lens shapes are generated, such as for illuminating shelves in commercial refrigerator food-display cases. The lens shapes are suitably thin for economical production by extrusion.
Patent details
- Publication number
- US 7,559,672
- Filing date
- 2008-05-23
- Grant date
- 2009-07-14
- Assignee
- Inteled Corporation
- Inventor(s)
- PARKYN WILLIAM A., PELKA DAVID G.
- CPC class
- F21V5/02
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