Color-Filter-Less LCD Backlight Modules with Time-Division Multiplexing
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Solution Overview
Problem
Color-filter-less liquid crystal displays face challenges with low brightness and severe crosstalk, making them unsuitable for practical applications due to the need for simultaneous light emission from all backlight sources and inadequate control over light emission timing.
Innovation Solution
The display device employs multiple backlight modules, each corresponding to at least two rows of pixel units, with a driving circuit and signal processor to control light sources in a time-division multiplexing manner, allowing sequential emission of red, green, and blue light, and using switch elements and collimating structures to optimize light distribution and reduce crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If all backlight sources emit light simultaneously, then the display can show full-color images, but the brightness remains low and crosstalk is severe
Solution Approach 1:
The backlight is divided into multiple independent backlight modules, each corresponding to different pixel regions. Each module can be controlled separately to emit light only when needed, preventing simultaneous emission from all sources and reducing crosstalk while maintaining brightness in active regions.
Solution Approach 2:
The patent implements time-division multiplexing where backlight modules are activated in sequential periods rather than simultaneously. Each module emits light during its designated time slot, allowing the display to achieve full-color images through temporal separation while eliminating the crosstalk and brightness issues of simultaneous emission.
2Illumination intensity
If multiple backlight modules are controlled independently, then brightness and image quality improve, but the control complexity increases
Solution Approach 1:
A single driving circuit is designed to control multiple backlight modules through time-division multiplexing. The driving circuit integrates the control functions for all modules, using a unified control architecture that manages sequential activation without requiring separate control circuits for each module, thus reducing overall system complexity.
Solution Approach 2:
The driving circuit implements periodic control sequences that automatically manage the activation timing of different backlight modules. This standardized periodic control approach simplifies the management of multiple modules by using repeated time-division patterns, reducing the complexity of coordinating independent module control.
3Reliability
If the refresh frequency is increased to reduce flicker, then display quality improves, but power consumption increases
Solution Approach 1:
The patent uses periodic time-division multiplexing to control backlight emission, allowing the display to achieve high refresh frequencies by sequentially activating different backlight modules. This periodic control enables frequent updates without requiring all modules to be active simultaneously, reducing the energy burden while maintaining display quality and minimizing flicker.
Data Source
AI summary
A display device includes: a plurality of backlight modules, where each backlight module includes a plurality of light sources capable of emitting light in at least three different colors; a color-filter-less liquid crystal display module including a plurality of pixel units arranged in an array form and a plurality of scanning lines coupled to the pixel units; where the plurality of backlight modules are arranged in parallel with the liquid crystal display module; where an orthogonal projection of each backlight module onto a plane where the liquid crystal display module is located corresponds to at least two rows of pixel units, where the pixel units in one row are along an length extension direction of each scanning line; and a driving circuit coupled to each backlight module and configured to apply a backlight driving signal to each backlight module.