Phase-Change Reflective Display with Liquid Crystal Gray Scale Control
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Solution Overview
Problem
Existing solid-state reflective display devices can only switch between two colors, lacking gray scale capability due to the phase-change material's limited states, which restricts their display quality.
Innovation Solution
Incorporating a liquid crystal cell on the display panel with a driving circuit that controls the deflection of liquid crystal molecules, in conjunction with a phase-change material layer and resonant cavity, to adjust the gray scale by filtering and reflecting light, allowing for multiple color states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If only phase-change material is used for color switching, then the device structure is simple and power consumption is low, but gray scale capability is lost and display quality is limited
Solution Approach 1:
The patent combines phase-change material layer and liquid crystal cell into a single pixel unit structure. The phase-change material provides color switching between two states while the liquid crystal cell overlays additional control layers to enable gray scale modulation, merging two different switching mechanisms into one integrated display unit.
Solution Approach 2:
The patent employs a composite structure where phase-change material and liquid crystal materials coexist in the same pixel unit. The phase-change material layer is positioned beneath the liquid crystal cell, creating a composite material system that leverages the bistable特性 of phase-change materials and the tunable optical properties of liquid crystals to achieve both color switching and gray scale control.
2Power
If phase-change material switches between crystalline and amorphous states, then power consumption is reduced, but only two color states are achieved
Solution Approach 1:
The patent introduces dynamic control capability by placing a liquid crystal cell on top of the phase-change material layer. While the phase-change material provides stable bistable switching, the liquid crystal cell adds dynamic tunability through voltage-controlled molecular orientation, enabling continuous adjustment of light transmission to create multiple color states including gray scales.
Solution Approach 2:
The patent changes the optical transmission parameter by combining two different switching mechanisms. The phase-change material alters refractive index between crystalline and amorphous states, while the liquid crystal cell modifies light transmission through voltage-controlled molecular alignment, collectively enabling multiple discrete color states beyond the traditional two-state limitation.
3Manufacturing precision
If liquid crystal cell is added to achieve gray scale, then display quality improves, but device thickness increases
Solution Approach 1:
The patent implements a nested structure where the liquid crystal cell is positioned directly on top of the phase-change material layer within the same pixel unit boundary. This nested arrangement allows the liquid crystal cell to overlay the phase-change material without requiring separate enclosures or additional spacing, thereby achieving gray scale capability while minimizing the increase in overall device thickness.
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 the display panel's ability to produce a range of gray scales, improving display quality by enabling the display of various colors and brightness levels.
Implementation Method 1
The solid-state reflective display utilizes a phase-change material, and is able to adjust the refractive index and/or the absorption performance of the phase-change material by controlling the phase-change material to switch between a crystalline state and an amorphous state
Implementation Method 2
the second driving module controls deflection of a plurality of liquid crystal molecules in the liquid crystal cell
Implementation Method 3
a resonant cavity, and a phase-change material layer sequentially disposed on the first substrate
Implementation Method 4
the display device is able to realize the display function through the reflection of ambient light
Data Source
AI summary
Display panel and display device are provided. The display panel includes a first substrate, a second substrate, and a plurality of pixel units. Each pixel unit includes a heating element, a reflective layer, a resonant cavity, and a phase-change material layer sequentially disposed on the first substrate, and a liquid crystal cell. The display panel also includes first signal lines extending along a row direction, second signal lines extending along the column direction, and a driving circuit in correspondence to each pixel unit. The driving circuit includes a first driving module and a second driving module that are connected to a same first signal line and a same second signal line. The first driving module drives the heating element to control the state of the phase-change material layer, and the second driving module controls the deflection of liquid crystal molecules in the liquid crystal cell.