LED Substrate Luminance Control for LCD Color Uniformity
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Solution Overview
Problem
Liquid crystal display (LCD) devices using light emitting diodes (LEDs) face challenges with color uniformity due to differences in luminous efficiency and aging characteristics among red, green, and blue LEDs, leading to increased manufacturing costs and circuit complexity.
Innovation Solution
An LED substrate is developed with thin film light sensors integrated on the substrate, along with a luminance control circuit, to sense and control the luminous intensities of LEDs, ensuring consistent luminance ratios and improved color uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate luminance control circuits are added for each LED color to maintain color uniformity, then color uniformity is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the luminance control circuits for multiple LED colors (red, green, blue) into a single integrated circuit on the substrate. This single circuit controls all LED colors simultaneously, eliminating the need for separate control circuits for each color. The merging approach maintains color uniformity while significantly reducing device complexity and manufacturing cost compared to having independent control circuits for each LED color.
2Manufacturing precision
If optical sensors are added to measure luminous intensities of LEDs, then color uniformity is improved, but manufacturing cost increases
Solution Approach 1:
The patent integrates optical sensors directly onto the substrate in close proximity to the LEDs, merging the sensing function with the existing substrate structure. This integration eliminates the need for separate external sensor components and their associated mounting and wiring, thereby reducing manufacturing cost while maintaining the ability to measure luminous intensities for color uniformity control.
Solution Approach 2:
The patent introduces a wavelength conversion layer as an intermediary between the LEDs and the optical sensors. This layer converts the light from different LED colors into a uniform wavelength range that the sensors can detect, enabling accurate luminous intensity measurement across all colors without requiring multiple specialized sensors, thus reducing overall manufacturing cost.
3Measurement precision
If multiple separate control circuits are used for R, G and B LEDs, then luminance control precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent combines multiple luminance control functions for red, green, and blue LEDs into a single integrated control circuit on the substrate. This unified circuit maintains precise luminance control for each color channel while significantly simplifying the manufacturing process and reducing component count, making the device easier and more cost-effective to manufacture compared to using multiple separate control circuits.
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 integration of thin film sensors and a luminance control circuit on the LED substrate reduces manufacturing costs and enhances color uniformity by maintaining consistent luminous intensity ratios, regardless of LED aging characteristics.
Implementation Method 1
a plurality of thin film sensors formed between the plurality of LEDs and the substrate, for sensing the luminous intensities of the plurality of LEDs
Data Source
AI summary
A luminance control circuit for controlling the luminance levels of different colored light sources that lends itself to easy incorporation into display devices is presented. A light emitting diode (LED) substrate includes a plurality of driving thin film transistors (TFTs) including a semiconductor layer deposited on a substrate. A plurality of LEDs for generating lights of different wavelengths is mounted respectively on the plurality of driving TFTs. A plurality of thin film sensors for sensing the luminous intensities of the plurality of LEDs is formed between the plurality of LEDs and the substrate. A luminance control circuit for controlling the driving TFTs has of a plurality of controlling TFTs including a semiconductor layer deposited on the substrate and is connected to the plurality of thin film sensors.