Liquid Crystal Display Optical Sheet Pattern Orientation
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Solution Overview
Problem
Liquid crystal display apparatuses face challenges in maintaining high contrast ratio and black visibility, especially at lateral sides, particularly in bright operation states, and suffer from light leakage and poor black visibility in dark operation states due to inadequate light management.
Innovation Solution
The apparatus includes a liquid crystal panel with a viewer-side polarizing plate and sequentially stacked first and second optical sheets, featuring specific optical patterns and refractive index differences to enhance viewing angles and contrast ratio without relying on antireflection layers, thereby improving black visibility and external appearance in both bright and dark states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a liquid crystal display apparatus uses conventional light management without specific optical patterns, then the structure is simple, but the contrast ratio and viewing angle deteriorate at lateral sides
Solution Approach 1:
The optical sheet is divided into multiple regions with different optical patterns: a first region with first optical patterns oriented at -10° to +10° relative to the vertical direction, and a second region with second optical patterns oriented at 80° to 100° relative to the vertical direction. This segmentation allows different parts of the display to have optimized light management for their specific viewing zones, improving overall contrast ratio and viewing angle without excessive complexity.
Solution Approach 2:
Different optical patterns are applied to different regions of the optical sheet based on local viewing requirements. The first optical patterns address lateral viewing angles, while the second optical patterns address vertical viewing angles. This local optimization ensures that each region contributes to improving contrast ratio and viewing angle performance where it is most needed.
2Illumination intensity
If antireflection films or low-reflection films are stacked on the surface, then black visibility is improved, but light leakage from the backlight cannot be fundamentally prevented
Solution Approach 1:
The patent extracts and addresses the root cause of light leakage by implementing specific optical patterns in the optical sheet that control light propagation from the backlight. Instead of merely treating the symptom (surface reflection) with antireflection films, the solution tackles the underlying issue of uncontrolled light paths by using optically anisotropic particles and specific pattern orientations to guide and manage light extraction, fundamentally preventing backlight leakage.
Solution Approach 2:
The patent changes the optical parameters of the optical sheet by incorporating optically anisotropic particles with specific orientation characteristics. The particles are oriented at specific angles (-10° to +10° and 80° to 100° relative to the vertical direction) to control light propagation. This parameter change in particle orientation enables precise control over light extraction angles, improving black visibility and preventing light leakage without requiring additional surface treatment layers.
3Ease of operation
If the liquid crystal display is optimized for bright operation state, then viewing angle is improved, but black visibility deteriorates in dark operation state
Solution Approach 1:
The optical sheet with specifically oriented optically anisotropic particles serves multiple functions simultaneously: it improves viewing angle in the bright operation state by controlling light distribution, and it prevents light leakage to improve black visibility in the dark operation state. The same optical structure with particles oriented at -10° to +10° and 80° to 100° achieves both objectives, eliminating the need for separate optimization schemes for different operation states.
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 configuration effectively enhances right and left viewing angles and black visibility, particularly in bright states, while maintaining good external appearance in dark states by optimizing light management through the optical sheets and polarizing layers, even without surface treatment layers.
Implementation Method 1
a first optical sheet and a second optical sheet sequentially stacked on a light incidence surface of the liquid crystal panel... optimizing light management through the optical sheets and polarizing layers
Implementation Method 2
the first optical sheet has a plurality of first optical patterns on a light exit surface thereof, an angle of a longitudinal direction of the first optical patterns relative to the vertical direction of the liquid crystal panel being from −10° to +10°
Implementation Method 3
a viewer-side polarizing plate stacked on a light exit surface of the liquid crystal panel... the viewer-side polarizing plate includes a polarizer
Data Source
AI summary
A liquid crystal display apparatus includes a liquid crystal panel; a viewer-side polarizing plate stacked on a light exit surface of the liquid crystal panel; and a first optical sheet and a second optical sheet sequentially stacked on a light incidence surface of the liquid crystal panel, and the viewer-side polarizing plate includes a polarizer and a contrast ratio or viewing angle-enhancing layer; the liquid crystal panel has a horizontal direction corresponding to a long side thereof and a vertical direction corresponding to a short side thereof; and the first optical sheet has a plurality of first optical patterns on a light exit surface thereof, an angle of a longitudinal direction of the first optical patterns relative to the vertical direction of the liquid crystal panel being from −10° to +10°.