This invention introduces a multi-material Bragg mirror that eliminates light leakage at the Brewster angle, enabling brighter, more efficient, and higher-quality solid-state lighting for automotive, projection, and medical applications.
Background: Conventional dichroic and Bragg mirrors, typically made from alternating layers of two materials, become partially transparent to p-polarized light at their Brewster angle. This leakage reduces brightness and efficiency in high-luminance systems such as automotive headlights, projectors, and medical illumination devices. Existing solutions—adding layers or adjusting thickness—add cost and complexity but do not fully prevent angle-dependent losses. A robust and manufacturable solution is needed to maintain consistent reflectivity and brightness across wide incidence angles.
Technology Overview: This invention describes an optoelectronic semiconductor light source composed of a semiconductor chip emitting primary radiation, a luminescence conversion element generating secondary radiation, and a novel Bragg mirror positioned between them. Unlike conventional two-material Bragg mirrors, this mirror uses at least three materials arranged into multiple alternating pairs with distinct Brewster angles. By staggering the Brewster angles, overlap is avoided so that when one pair becomes transparent, another remains reflective. This design minimizes leakage, maintains wide angular reflectivity, and ensures efficient, reliable operation of high-brightness solid-state lighting systems.
Advantages: • Eliminates light leakage at Brewster angles with multi-material mirror design • Provides higher brightness and efficiency vs. two-material dichroic filters • Maintains wide-angle reflectivity for stable performance across incidence angles • Improves color conversion uniformity and reduces spectral distortion • Compatible with existing lighting architectures for straightforward integration
Applications: • High-efficiency automotive headlights requiring brighter and energy-efficient illumination • Laser and LED projection systems demanding high luminance and improved image quality • Stage, industrial, and specialty illumination systems with precise light management needs • Medical lighting such as surgical lamps and endoscopes requiring reliable, intense output • Advanced display technologies seeking improved brightness and color uniformity
Intellectual Property Summary: • US Patent 10,808,893 – Application No. 16/291,679, Filed 03/04/2019, Published US 2020-0284401 A1, Granted 10/20/2020 • European Patent Office – Application No. PCT/EP2020/055295, Filed 02/28/2020, Published 09/04/2021, Status: Filed • Germany – Application No. 112020001069.4, Filed 08/17/2021, Granted Patent No. 112020001069 on 05/05/2022
Stage of Development: Patented and validated in laboratory settings with demonstrated improvements in brightness, efficiency, and angular stability. TRL ~5–6.
Licensing Status: This technology is available for licensing.
Licensing Potential: High-value opportunity for automotive, projection, and medical device manufacturers seeking advanced light management solutions to enhance brightness, efficiency, and color stability in demanding illumination systems.
Additional Information: Optical performance data, angular reflectivity plots, and integration details with semiconductor chips are available upon request.
Inventors: David Klotzkin, Alan Lenef, Xin Wen