Polarization Azimuth Compensator for LCD Light Leakage
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Solution Overview
Problem
Liquid crystal displays and projectors face challenges with viewing angle dependency and light diffraction due to polarizing plate structures, leading to light leakage and uneven brightness, especially in high-resolution applications with small panel sizes and high pixel densities.
Innovation Solution
Incorporating a polarization azimuth compensator, comprising biaxial phase difference layers or C and A plates, between polarizers and the liquid crystal cell to align polarization planes and compensate phase differences, thereby preventing light leakage and improving contrast and brightness across wide viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two biaxial phase difference plates are laminated on one polarizing plate to compensate polarization plane inclination, then light leakage is prevented, but device complexity increases
Solution Approach 1:
The invention divides the polarization compensation function into two separate compensators: one placed between the incident-side polarizer and liquid crystal cell, and another between the exit-side polarizer and liquid crystal cell. This segmentation allows each compensator to handle specific angular deviations, reducing the complexity compared to using multiple layers on a single polarizing plate.
Solution Approach 2:
The invention introduces polarization compensators as intermediary elements that mediate between the polarizers and the liquid crystal cell. These compensators actively correct the polarization plane inclination caused by oblique incident light, preventing light leakage without requiring complex multi-layer structures on the polarizing plates themselves.
2Manufacturing precision
If high pixel density is achieved in small panel sizes for high-resolution displays, then image quality improves, but light diffraction increases causing brightness unevenness
Solution Approach 1:
The invention changes the optical parameters of the light path by introducing polarization compensators that adjust the polarization state of light before it reaches the liquid crystal cell. This parameter adjustment compensates for diffraction effects caused by high pixel density, maintaining brightness uniformity across the display.
Solution Approach 2:
The polarization compensators perform preliminary correction of polarization plane inclination before the light enters the liquid crystal cell. By pre-compensating for the angular deviations that will cause light leakage and brightness unevenness, the system prevents these issues before they manifest in the final display output.
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 polarization azimuth compensator effectively aligns polarization planes and compensates for diffraction-induced phase differences, enhancing light extinction ratios and maintaining high contrast and brightness, even at varying viewing angles, particularly in high-resolution liquid crystal projectors.
Implementation Method 1
The polarizing plate decomposes the incident non-polarized light to two polarized light components which are perpendicular to each other. Further the polarizing plate blocks light of the polarized light component parallel to an absorption axis, and transmits light of the polarized light component perpendicular to the absorption axis.
Implementation Method 2
A liquid crystal cell which performs light modulation with use of optical rotatory property and birefringence in liquid crystal molecules
Implementation Method 3
A liquid crystal cell which performs light modulation with use of optical rotatory property and birefringence in liquid crystal molecules. The molecules are rotated gradually in a thickness direction of the liquid crystal layer so that the long axes of the liquid crystal molecules twist by 90 degrees as a whole
Implementation Method 4
The polarizing plate is originally constructed for absorbing light whose polarization plane is parallel to an absorption axis of the polarizing plate and transmitting light perpendicular to the absorption axis of the polarizing plate among light entering the polarizing plate.
Implementation Method 5
a light extinction ratio in a cross-nicol also depends on the incident angle, thus resulting in a so-called viewing angle dependency. Accordingly, there causes one of reasons for impossibility of achieving a preferable light extinction ratio.
Data Source
AI summary
A polarization azimuth compensation layer (31) is effective in aligning a polarization plane of light obliquely entering an incident-side polarizing plate (30) with a polarization plane of light entering the incident-side polarizing plate (30) in a direction of a normal line. A retardation compensation layer (41) is disposed nearer a liquid crystal layer (34) than a microlens array (40) diffracting part of incident light, to compensate a phase difference due to the liquid crystal layer (34). Diffracted light caused by the microlens array (40) and a TFT circuit pattern (46) enters a polarization azimuth compensation layer (36). The polarization azimuth compensation layer (36) prevents leakage of light by aligning a polarization plane of the diffracted light to be parallel to an absorption axis of an exit-side polarizing plate (37).