Multi-Channel Light Engine Using Deep Red LED and Dichroic Mirrors
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Solution Overview
Problem
Current multi-channels light engine apparatuses face a bottleneck in red light channel brightness due to the inefficiencies of short wavelength red-amber LEDs, which suffer from low quantum efficiency, thermal degradation, and high current roll over issues, limiting their performance in high brightness applications.
Innovation Solution
Incorporating a long wavelength deep red light source with a peak wavelength of 650-660 nm, combined with short wavelength red-amber LEDs, using dichroic mirrors to form a co-axial light path without increasing etendue, allowing for higher quantum efficiency and thermal stability, and enabling higher current density operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If short wavelength red-amber LED is used for red light channel, then device complexity is reduced, but red light channel brightness is limited due to low quantum efficiency and thermal degradation
Solution Approach 1:
The patent combines two different red light sources (short wavelength red-amber LED and long wavelength deep red LED) into a single red light channel system. This merging allows the system to leverage the high quantum efficiency of deep red LEDs (650-660nm) while maintaining the advantages of red-amber LEDs, thereby significantly increasing red light channel brightness without substantially increasing device complexity
Solution Approach 2:
The patent uses a composite light source system combining two types of LED materials with different wavelength characteristics. The short wavelength red-amber LED (AlInGaP material) and long wavelength deep red LED are used together to create a composite red light output that overcomes the limitations of individual LED types, achieving both high brightness and high quantum efficiency
2Illumination intensity
If red-amber LED is driven at high current density to increase brightness, then illumination intensity improves, but thermal degradation and current roll over increase
Solution Approach 1:
The patent changes the wavelength parameter of the red light source by introducing a long wavelength deep red LED (650-660nm) alongside the existing red-amber LED. This parameter change allows the system to operate at high current densities without thermal degradation because deep red LEDs have superior thermal stability and lower current roll over, thereby improving reliability while maintaining high illumination intensity
Solution Approach 2:
The long wavelength deep red LED acts as an intermediary that enables high current density operation. By adding this intermediate wavelength source, the system can distribute the light output burden, allowing the red-amber LED to operate at lower current densities while the deep red LED contributes significantly to the overall brightness, thus reducing thermal degradation and improving reliability
3Reliability
If phosphor converted red light is used to solve thermal degradation, then reliability improves, but system efficiency decreases due to wide spectral bandwidth and dichroic mirror cutting loss
Solution Approach 1:
The patent replaces the phosphor converted red light approach with direct emitting deep red LEDs. Instead of using phosphor materials that require dichroic mirrors for color separation (which cause cutting losses), the invention uses voltage-driven deep red LEDs that emit directly at 650-660nm. This eliminates the need for phosphor conversion and dichroic mirrors in the red channel, thereby reducing energy loss while maintaining thermal stability
Solution Approach 2:
The patent substitutes the optical/phosphor-based red light generation system with an electrical LED-based system. By replacing phosphor conversion (which requires complex optical paths and dichroic mirrors) with direct emitting deep red LEDs, the system eliminates mechanical/optical components that cause energy loss, thereby improving system efficiency while maintaining reliability
4Illumination intensity
If long wavelength deep red light is added to increase red channel brightness, then red light output improves, but device complexity increases
Solution Approach 1:
The patent merges the short wavelength red-amber LED and long wavelength deep red LED into a unified red light channel system. By combining these two light sources with different wavelength characteristics, the system achieves significantly increased red channel brightness. The merging is done in a way that leverages the complementary strengths of each LED type without substantially increasing device complexity
Solution Approach 2:
The deep red LED serves multiple functions: it provides high quantum efficiency red light output, enables high current density operation with superior thermal stability, and reduces reliance on red-amber LED duty cycle. This multi-functionality allows the system to achieve higher red channel brightness without proportional increases in device complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration significantly enhances red light channel brightness, reduces dichroic mirror cutting loss, and increases color gamut, achieving high brightness outputs of up to 5000 lm while maintaining compact size and efficient light utilization.
Implementation Method 1
a first red light device configured to emit a red light beam with peak wavelength longer than 630 nm
Implementation Method 2
a first beam combiner configured to combine the red light beam, the green light beam and the blue light beam so as to form a co-axial light path; wherein the first beam combiner comprises a X-plate dichroic mirror
Data Source
AI summary
A high brightness light engine apparatus is disclosed, comprising at least one long red wavelength light source with a peak wavelength longer than 630 nm, at least one green wavelength light source and at least one blue wavelength light source. Furthermore, the long wavelength red light may be combined with short wavelength red light and green/blue lights into a co-axial light path by at least one beam combiner such as wedged dichroic mirror, X-plate dichroic mirror or a dichroic X-cube. A 3-channels/4-channels/5-channels light engine apparatus and a hybrid laser LED light engine apparatus are disclosed that comprises at least a long wavelength red light source, one blue light source, and one converted green light source, combined by a dichroic mirror together with a X-plate dichroic mirror, a wedged dichroic mirror or a dichroic X-cube without Etendue increase to achieve high brightness light engine output as high as 5000 lm.