Polymer Liquid Crystal Displays for Low-Scattering Transmission
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Solution Overview
Problem
Existing display devices using polymer dispersed liquid crystal face issues with light absorption and scattering, leading to reduced luminance and display quality degradation due to the presence of organic insulating films between the transparent substrate and pixel electrodes, as well as undesirable capacitance between wiring lines.
Innovation Solution
The display device is designed with an organic insulating film thickness between the transparent substrate and pixel electrode minimized or absent, and the film is patterned to reduce its volume, accompanied by a light-shielding layer to block scattered light and minimize capacitance between wiring lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an organic insulating film is formed between the transparent substrate and pixel electrode, then electrical insulation is improved, but light absorption and scattering increase leading to reduced luminance
Solution Approach 1:
The patent applies this principle by using an extremely thin organic insulating film (thickness of 1 µm or less, preferably 0.5 µm or less) between the transparent substrate and pixel electrode. This thin film maintains electrical insulation functionality while minimizing light absorption and scattering, thereby preserving luminance. The thin film structure allows light to pass through with minimal interference while still providing the necessary electrical isolation.
2Manufacturing precision
If wiring lines are arranged close together to increase display resolution, then display quality is improved, but capacitance between wiring lines increases
Solution Approach 1:
The patent extracts the harmful capacitance effect by introducing a light-shielding layer positioned between adjacent wiring lines. This light-shielding layer acts as an electrical barrier that reduces parasitic capacitance between closely spaced wiring lines, allowing high-resolution display designs with closely spaced conductors to be implemented without excessive capacitance interference.
3Illumination intensity
If a light-shielding layer is added to block scattered light, then display quality is improved, but device complexity increases
Solution Approach 1:
The patent applies multi-functionality by designing the light-shielding layer to serve multiple purposes simultaneously: (1) blocking scattered light to improve display quality and contrast ratio, (2) reducing parasitic capacitance between adjacent wiring lines, and (3) providing structural support and positioning for the pixel electrode. By making this single layer perform multiple functions, the overall device complexity is minimized while achieving multiple performance goals.
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 display quality by reducing light absorption and scattering, maintaining luminance, and minimizing undesirable capacitance, thereby improving overall display performance.
Implementation Method 1
a liquid crystal layer including polymers and liquid crystal molecules and capable of switching between a scattering state and a transmitting state
Implementation Method 2
switching between a scattering state and a transmitting state
Implementation Method 3
a light-shielding layer to block scattered light
Data Source
AI summary
According to one embodiment, a display device includes a first substrate, a second substrate, a liquid crystal layer including polymers and liquid crystal molecules, and a light-emitting element. The first substrate includes a transparent substrate, a scanning line, a signal line crossing the scanning line, a switching element electrically connected to the scanning line and the signal line, an organic insulating film overlapping the switching element, and a pixel electrode electrically connected to the switching element. A thickness of the organic insulating film located between the transparent substrate and the pixel electrode is less than a thickness of the organic insulating film overlapping the switching element.