Micro-LED Mirror Backlight for Uniform Display With Lower Heat
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Solution Overview
Problem
Existing vehicular interior rearview mirror assemblies face challenges with lighting uniformity, cost, heat load, and current draw, particularly in providing effective backlighting for information display screens.
Innovation Solution
The use of a micro-LED backlight system with a two-dimensional close-packed array of micro-LEDs on a flexible or rigid printed circuit substrate, integrated into the interior rearview mirror assembly to provide uniform and efficient lighting for a full display mirror, reducing heat generation and power consumption while enhancing brightness and field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional LED backlighting is used in vehicular mirror assemblies, then illumination is provided for display screens, but lighting uniformity deteriorates and heat load increases
Solution Approach 1:
The backlighting system is segmented into multiple individual LED elements arranged in an array across the mirror assembly. This segmentation allows each LED to be independently positioned and controlled, improving lighting uniformity across the display screen while distributing heat generation across multiple smaller sources rather than concentrated sources, thereby reducing overall heat load.
Solution Approach 2:
Different regions of the mirror assembly are provided with LEDs having different characteristics tailored to local requirements. The system incorporates LEDs with varying color temperatures and luminous intensities in different zones to achieve uniform overall illumination. This local quality approach also allows for optimized heat management in different regions of the assembly.
2Illumination intensity
If conventional LED backlighting is used in vehicular mirror assemblies, then display illumination is achieved, but current draw increases and cost increases
Solution Approach 1:
The system utilizes LEDs with optimized electrical and optical parameters, including forward voltage and luminous efficiency, to reduce current draw while maintaining required display brightness. The patent employs LEDs with improved luminous efficacy that convert electrical energy to light more efficiently, thereby reducing the current required to achieve the same illumination level.
3Illumination intensity
If conventional LED backlighting is used in vehicular mirror assemblies, then illumination is provided, but lighting uniformity deteriorates
Solution Approach 1:
The patent replaces complex mechanical optical systems (such as reflectors, diffusers, and lenses required in conventional backlighting) with a simplified array of LEDs that directly emit light. This substitution eliminates the need for additional optical components and reduces the quantity of materials required while achieving superior lighting uniformity through precise LED positioning and control.
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
The micro-LED system offers improved lighting uniformity, reduced heat and power consumption, and increased brightness, providing a more efficient and effective display solution for vehicular information systems, including enhanced rearward viewing capabilities and reduced blind zones.
Implementation Method 1
The display device comprises a display screen (such as a thin film transistor (TFT) display screen) that is backlit by a plurality of micro light emitting diodes (micro-LEDs)
Implementation Method 2
The interior mirror reflective element comprises a transflective mirror reflector whereby the mirror reflector reflects light that is incident on the reflective element and partially transmits illumination emitted from the display device through the mirror reflective element
Data Source
AI summary
A vehicular lighting assembly includes an plurality of micro-LEDs disposed at a substrate. Width dimension of each individual micro-LED of the plurality of micro-LEDs is less than 500 microns, and length dimension of each individual micro-LED of the plurality of micro-LEDs is less than 500 microns. Packing density of micro-LEDs of the plurality of micro-LEDs at the substrate is at least 10 micro-LEDs per square centimeter. Each individual micro-LED of the plurality of micro-LEDs, when the vehicular lighting assembly is operated to emit light, passes less than 4 mA electrical current. The vehicular lighting assembly is configured to be disposed at a portion of a vehicle equipped with the vehicular lighting assembly, With the vehicular lighting assembly disposed at the portion of the vehicle, light emitted by the plurality of micro-LEDs, when the vehicular lighting assembly is operated to emit light, is viewable at the portion of the vehicle.