Reflective LCD Panel White Balance via Polarizer and LC Parameters
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Solution Overview
Problem
Current reflective LCD panels exhibit a yellowish hue due to unexpected optical path differences caused by the angle of liquid crystal molecules and the thickness of the liquid crystal layer, which affects the color balance and display quality.
Innovation Solution
The reflective LCD panel is optimized by selecting a polarizing film and adjusting the birefringence difference (Δn) and thickness (d) of the liquid crystal layer, ensuring that 2Δn*d falls within the range of 120 nm to 170 nm, and the polarizing film's color coordinates are set to (a, b) within specific ranges, to match the parameters of the polarizing film, thereby achieving better white balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a polarizer is disposed on the reflective LCD panel to convert natural light into polarized light and control transmittance, then the display can show images, but unexpected optical path differences are generated due to liquid crystal molecule angle and liquid crystal layer thickness, causing yellowish hue and poor white balance
Solution Approach 1:
The patent applies parameter changes by precisely controlling the liquid crystal layer thickness (d) and birefringence difference (Δn) to satisfy the optical path difference condition 2Δn*d=Δλ, where Δλ is within a specific range. This parameter optimization compensates for the yellowish hue caused by conventional parameters, achieving accurate white balance while maintaining display brightness through the polarizer.
2Ease of manufacture
If the liquid crystal layer thickness and birefringence difference are not optimized, then the manufacturing process is simpler, but the optical path difference causes color shifts and yellowish hue
Solution Approach 1:
The patent establishes specific parameter ranges for liquid crystal layer thickness (d) and birefringence difference (Δn) that satisfy 2Δn*d=Δλ, where Δλ is controlled within an optimal range. These parameter specifications provide clear manufacturing guidelines that balance ease of production with precise color accuracy, eliminating the yellowish hue without overly complicating the manufacturing process.
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 adjustment ensures optimal white balance and color accuracy, minimizing color shifts and providing a more accurate representation of colors, particularly by controlling the proportion of red, green, and blue wavelengths in the white light, thus enhancing the display's color rendition.
Implementation Method 1
The liquid crystal in the liquid crystal layer has a birefringence difference Δn, the liquid crystal layer has a thickness d, and when the reflective LCD panel is in a white frame, 2Δn*d=Δλ is satisfied
Implementation Method 2
The polarizer allows the light wave in a single polarization direction to pass through and absorbs the light wave perpendicular to the single polarization direction
Implementation Method 3
Δλ is defined as an optical path difference obtained when a forward light vertically enters the liquid crystal layer and is reflected by the array substrate
Data Source
AI summary
A reflective LCD panel includes a color filter substrate, an array substrate, a liquid crystal layer and a polarizing film. The array substrate and the color filter substrate are disposed oppositely. The liquid crystal layer is disposed between the color filter substrate and the array substrate and has an alignment direction. The polarizing film is disposed on the color filter substrate, and color coordinates of the polarizing film in the CIE1976 color space are (a, b), wherein 0.05≤a≤0.2 and −5≤b≤0. The liquid crystal layer has a birefringence difference Δn, the liquid crystal layer has a thickness (d), when the reflective LCD panel is in a white frame, 2Δn*d=Δλ is satisfied, Δλ is the optical path difference obtained when a forward light vertically enters the liquid crystal layer and is reflected by the array substrate, and 120 nm≤Δn*d≤170 nm.