LCD Backlight Timing for Reduced Color Mixing and Higher Purity
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Solution Overview
Problem
Conventional liquid crystal display (LCD) technologies suffer from reduced image resolution and color purity due to color mixing caused by overlapping lights in adjacent fields during time-division sequential driving methods.
Innovation Solution
The LCD apparatus divides each frame into multiple fields with light-generating units that sequentially generate lights with different colors, where the initial light-generating time of each unit is delayed by a predetermined interval, allowing for a peak light intensity in non-overlapping periods to minimize color mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a color filter LCD apparatus displays a color image using red, green and blue color filters, then color image display is achieved, but image resolution is reduced to 1/3 of the number of actual pixels and color purity is reduced
Solution Approach 1:
The patent removes the color filters from the LCD structure entirely, replacing the spatial color separation method with a temporal color sequential method. This extraction of the color filter component eliminates the resolution loss while maintaining color display capability through time-division multiplexing of red, green and blue light sources
Solution Approach 2:
The patent employs periodic activation of different color light sources (red, green, blue LEDs) in sequential time intervals within each frame period. This periodic color sequential driving method displays color images by temporally multiplexing monochromatic light sources, achieving full-resolution color display without color filters
2Ease of manufacture
If the frame is divided into a plurality of fields sequentially generating lights having different colors, then color image display is improved, but light from adjacent fields overlaps causing color mixing
Solution Approach 1:
The patent applies preliminary dimming or turning off of adjacent color light sources before they would overlap in time. By controlling the timing and duration of each color field's light generation, the system prevents color mixing at the boundaries between fields, ensuring clean color separation while maintaining sequential color display
Solution Approach 2:
The patent dynamically adjusts the timing and intensity of light generation for each color field based on the liquid crystal response characteristics. By optimizing the on/off timing of each color source and adjusting brightness levels, the system adapts to prevent color mixing while maintaining vivid color display
Data Source
AI summary
A liquid crystal display (LCD) apparatus time-divides a frame into a plurality of fields, in which lights having a color different from each other, are generated. The LCD apparatus includes a backlight unit. The backlight unit includes n of light-generating units sequentially generating the lights in the fields. An initial light-generating time of an nth light-generating unit being delayed by a predetermined time gap relative to the (n-1)th light-generating unit so that each of the fields includes a first period, in which one of the lights is generated, and a second period, in which at least two of the lights are generated. The light-generating units generate a peak light having a peak intensity in the first period. Thus, the intensity of light or the time period for which the light is generated, is controlled so that color mixing is minimized and color purity is improved.