LCD with COP Retarder and RM for Reflection Control
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Solution Overview
Problem
Liquid crystal displays (LCDs) face reduced contrast ratio and degraded image quality due to unwanted ambient light reflections, especially in high ambient lighting conditions, as conventional configurations with linear polarisers are not compatible with circular polarisers, which are effective in absorbing internal reflections.
Innovation Solution
The addition of a uniform unpatterned retarder layer inside the LC cell and a circular polariser composed of an external and internal retarder layer, made of cyclic olefin polymer or copolymer materials, to negate each other's polarization control functions, reducing internal reflections and maintaining high contrast ratio in both low and high ambient lighting conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a circular front polariser is added to absorb internal reflections and improve high ambient lighting appearance, then contrast ratio and image quality in high ambient light are improved, but the LC mode configuration becomes incompatible and dark room performance degrades
Solution Approach 1:
The invention divides the polarisation control function into two separate components: a circular front polariser for absorbing internal reflections in high ambient light, and a phase compensation (retarder) film integrated into the touch panel to compensate for the optical axis rotation of the LCD. This segmentation allows each component to address specific aspects of the problem without interfering with the other's function.
Solution Approach 2:
The phase compensation film acts as an intermediary element between the LCD and the circular front polariser. It compensates for the optical axis rotation caused by the LCD's liquid crystal layer, thereby maintaining compatibility between the LC mode configuration and the circular polariser while preserving dark room performance.
2Illumination intensity
If anti-reflection or anti-glare films are used to reduce reflections from the front surface, then high ambient lighting appearance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The invention merges the phase compensation function with the touch panel structure by integrating the phase compensation film into the touch panel assembly. This combination eliminates the need for separate anti-reflection films while maintaining reflection reduction capabilities, thereby reducing manufacturing complexity and cost.
3Reliability
If phase compensation films are integrated into the touch panel, then compatibility with circular polarisers and dark room performance are improved, but manufacturing precision requirements increase
Solution Approach 1:
The phase compensation film serves multiple functions simultaneously: it compensates for optical axis rotation to enable circular polariser compatibility, maintains dark room performance, and is integrated into the touch panel structure. This multi-functionality reduces the need for additional separate components and simplifies the overall 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 configuration enhances contrast ratio and image quality by minimizing unwanted ambient light reflections, particularly from internal components, while retaining the high-quality transmissive display performance associated with the LC mode, allowing for improved visibility in high ambient lighting without degrading dark-room image quality.
Implementation Method 1
The external retarder and the internal RM retarder are configured such that optical properties (for example light polarization control function) of the external retarder and the internal retarder are matched to negate each other
Implementation Method 2
minimizing unwanted internal ambient light reflections
Implementation Method 3
light transmitted by the display from the backlight to the viewer is modulated by the LC layer
Data Source
AI summary
A liquid crystal device (LCD) is configured for minimizing unwanted internal ambient light reflections. The LCD includes a plurality of layers, the layers comprising from a viewing side: a first linear polariser; an external retarder that is made of a cyclic olefin polymer (COP) material or a cyclic olefin copolymer (COC) material; a colour filter substrate; a colour filter layer; an internal reactive mesogen (RM) retarder alignment layer; an internal reactive mesogen (RM) retarder; a liquid crystal (LC) layer; and a second linear polarizer. The external retarder and the internal RM retarder are configured such that the optical properties (for example light polarization control function) of the external retarder and the internal retarder are matched to negate each other for light passing through the external retarder and the internal RM retarder. The LCD simultaneously maintains high image quality in both high and low ambient lighting conditions.