Liquid Crystal Display with Dichroic Dye and Reflective Polarizer
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Solution Overview
Problem
Conventional liquid crystal displays face limitations in power consumption and dependency on ambient conditions, with transmissive displays consuming high power and reflective displays having time and place restrictions, while semi-transmissive displays complicate processes and lower aperture ratios.
Innovation Solution
A liquid crystal display that operates in both reflection and transmission modes using a single reflective polarizer and dichroic dye molecules, allowing for black and white gradation without separate transmission and reflection regions, and eliminating the need for an alignment film to reduce manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a transmissive liquid crystal display uses a backlight unit to provide light, then image display quality is improved, but power consumption increases significantly
Solution Approach 1:
The display panel dynamically switches between reflection mode and transmission mode based on ambient light conditions. In bright environments, reflection mode is used to save power; in dark environments, transmission mode with backlight unit is activated for better image quality. This dynamic adaptation resolves the contradiction between power consumption and display quality.
Solution Approach 2:
The display panel is designed to perform multiple functions: it can operate in both reflection mode (using ambient light) and transmission mode (using backlight unit). This multi-functionality allows the device to adapt to different usage scenarios, achieving both low power consumption and high display quality depending on the situation.
2Use of energy by moving object
If a reflective liquid crystal display is used to reduce power consumption, then battery life is extended, but time and place restrictions are imposed due to dependency on ambient conditions
Solution Approach 1:
The display dynamically adapts its operating mode based on ambient light conditions. When ambient light is sufficient, reflection mode is used for low power consumption. When ambient light is insufficient, the system automatically switches to transmission mode with backlight unit to maintain display functionality. This dynamic adaptation eliminates time and place restrictions while maintaining low power consumption characteristics.
Solution Approach 2:
By incorporating both reflection and transmission modes, the display becomes universally applicable across different environments and time conditions. The dual-mode capability allows the device to function effectively whether used outdoors in bright light or indoors in dim lighting, removing the limitations of single-mode reflective displays.
3Adaptability or versatility
If separate transmission and reflection regions are provided in one pixel to achieve both modes, then operational flexibility is improved, but aperture ratio is lowered
Solution Approach 1:
Instead of dividing each pixel into separate transmission and reflection regions, the patent segments the display into two distinct operational modes at the panel level. Each pixel maintains its full aperture in both modes, but the overall panel switches between modes based on ambient light conditions. This approach preserves the aperture ratio while achieving operational flexibility.
Solution Approach 2:
The patent resolves the contradiction by adding a temporal/dimensional dimension to the mode switching. Rather than spatially dividing pixels, the system switches modes over time based on ambient conditions. This dimensional approach allows full aperture utilization in both transmission and reflection modes without compromising aperture ratio.
4Device complexity
If a single reflective polarizer is used to eliminate the need for additional polarizers, then manufacturing cost is reduced and device complexity is lowered, but achieving black and white gradation becomes more challenging
Solution Approach 1:
The patent uses parameter changes in the liquid crystal layer (changing the arrangement state of liquid crystal molecules and dichroic dye molecules) to control light transmission and achieve black and white gradation. By controlling the orientation and alignment parameters of the liquid crystal molecules, the system achieves precise control over light passage using only a single reflective polarizer, eliminating the need for additional polarizers while maintaining manufacturing precision.
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
Enables efficient power usage, eliminates the need for additional polarizers, and improves screen brightness and manufacturing cost-effectiveness by achieving black and white gradation in both modes with a single reflective polarizer.
Implementation Method 1
the liquid crystal layer includes liquid crystal molecules and dichroic dye molecules, and has a first arrangement state in which the liquid crystal molecules and the dichroic dye molecules are arranged at random
Implementation Method 2
the liquid crystal layer includes liquid crystal molecules and dichroic dye molecules
Implementation Method 3
a reflective polarizer disposed outside the first substrate... the reflective polarizer may transmit light vibrating in a first direction, and may reflect light vibrating in a second direction different from the first direction
Data Source
AI summary
A liquid crystal display includes: a display panel including first and second substrates opposite to each other, and a liquid crystal layer disposed between the first and second substrates; a reflective polarizer disposed outside the first substrate; and a backlight unit disposed outside the first substrate to provide light to the display panel, where the liquid crystal layer includes liquid crystal molecules and dichroic dye molecules, and the liquid crystal layer has a first arrangement state in which the liquid crystal molecules and the dichroic dye molecules are arranged at random.