Micro-LED Backlight System with Bare Die Emitters
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Solution Overview
Problem
Existing backlight systems using light-emitting diodes suffer from reduced contrast ratio due to light leakage, limited on/off optical ratio, and inefficiencies in manufacturing, which restrict display thinness, flexibility, and contrast improvement.
Innovation Solution
A backlight system utilizing bare die micro-light-emitting diodes (micro-LEDs) with contact pads on a substrate, where the number of light valves exceeds the number of light emitters, enabling improved light uniformity and local dimming through passive or active-matrix control, and micro-transfer printing for increased density and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional light-emitting diodes are used in backlight systems, then light emission is achieved, but the display thickness increases and the number of light emitters in the display area is limited
Solution Approach 1:
The patent segments the light emitter into micro-scale regions (red, green, and blue sub-regions) within a single LED structure, allowing multiple color light emitters to be integrated in a compact form factor. This segmentation enables increased emitter density without proportionally increasing display thickness.
Solution Approach 2:
The patent employs a nested structure where multiple light-emitting layers (red, green, blue regions) are arranged in a nested or closely integrated configuration within the backlight assembly, allowing multiple functions to be packed into a reduced thickness while maintaining high emitter density.
2Productivity
If traditional light-emitting diodes are used in backlight systems, then light emission is achieved, but manufacturing efficiency is reduced due to individual placement requirements
Solution Approach 1:
The patent merges multiple light-emitting functions into a single integrated LED component with red, green, and blue light-emitting regions. This consolidation eliminates the need for individual placement of separate red, green, and blue LEDs, significantly simplifying the manufacturing process and improving productivity.
Solution Approach 2:
The patent creates a universal light-emitting diode structure that performs multiple functions (emitting red, green, and blue light) through a single component design. This multi-functional LED can be placed as one unit rather than requiring three separate placements, thereby improving manufacturing efficiency.
3Reliability
If light-emitting diodes are used with limited on/off optical ratio, then light emission control is achieved, but contrast ratio is reduced due to light leakage
Solution Approach 1:
The patent implements local quality control by providing separate control signals for red, green, and blue light-emitting regions within the backlight system. This enables independent dimming and on/off control of specific color regions, improving the ability to manage light leakage and enhance contrast ratio in different areas of the display.
Solution Approach 2:
The patent employs dynamic control of light emission through pulse width modulation or similar techniques for each color region, allowing real-time adjustment of light output levels. This dynamic control improves the on/off optical ratio and reduces light leakage, thereby enhancing contrast ratio.
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 approach enhances display contrast, reduces power usage, and improves manufacturing efficiency by allowing for more precise control of light emission and increased density of light emitters, leading to improved image quality and thinner displays.
Implementation Method 1
light-emitting diodes can produce relatively narrow-bandwidth colored light
Implementation Method 2
light-emitting diodes have provided an efficient alternative
Data Source
AI summary
A backlight system includes a backplane and a plurality of bare die light emitters disposed on the backplane. Each light emitter has a light-emitter substrate and contact pads on the light-emitter substrate through which electrical current is supplied to cause the light emitter to emit light. A plurality of first and second backplane conductors are disposed on the backplane for conducting control signals to control the light emitters through the contact pads. A plurality of light valves is disposed to receive light from the light emitters. The number of light valves is greater than the number of light emitters.