Reflective Display Device Electrochromic Control Contrast Ratio
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Solution Overview
Problem
Conventional reflective display devices suffer from low contrast ratios due to uncontrolled reflectance, which prevents them from functioning properly as both reflective and display devices.
Innovation Solution
A reflective display device with a reflective control element comprising a transparent electrode, a reflective electrode, a counter layer, an electrochromic layer, and an electrolytic layer, which controls reflectance by undergoing electrochemical oxidation-reduction reactions to change colors or transparency, allowing for simultaneous operation in display and reflective modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a reflective metal is used in the reflective area to maintain high reflectance, then the device can function as a mirror, but the contrast ratio is lowered when an image is displayed
Solution Approach 1:
The reflective area incorporates an electrochromic layer that can dynamically change its optical properties between reflective and non-reflective states based on applied voltage, allowing the device to adapt between mirror and display modes
Solution Approach 2:
The reflectance parameter of the reflective area is made controllable through electrochemical reactions in the electrochromic layer, enabling transition between high reflectance (mirror mode) and low reflectance (display mode) states
2Adaptability or versatility
If high reflectance is maintained in the reflective area, then the device can serve as a mirror, but it cannot be properly operated as a display device
Solution Approach 1:
The reflective area is designed to perform dual functions: acting as a mirror when in reflective mode and serving as a background for display when in non-reflective mode, controlled by the electrochromic layer's state
Solution Approach 2:
The reflective area transitions between two functional states through voltage control of the electrochromic layer, enabling the device to switch between mirror and display operations
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
The solution improves contrast ratios by absorbing or transmitting light depending on the mode of operation, enabling the device to function effectively as both a display and a mirror.
Implementation Method 1
a reflective control element provided in the reflective area, controlling reflectance of externally incident light
Implementation Method 2
controlling reflectance by undergoing electrochemical oxidation-reduction reactions to change colors or transparency
Implementation Method 3
When an image is not displayed on the display area, the reflective metal 93 may serve as a mirror by reflecting light
Implementation Method 4
The solution improves contrast ratios by absorbing or transmitting light depending on the mode of operation
Data Source
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AI summary
A reflective display device is disclosed which comprises first and second substrates (105, 405) facing each other, each of which includes an emissive display area and a reflective area, a display element (200) provided in the display area and comprising an organic light-emitting layer (240), and a reflective control element (400) provided in the reflective area and comprising, inter alia, an electrochromic layer (460) and an electrolyte (470), wherein the reflective control element (400) is driven by a driving element (300), e.g. a thin-film transistor, so as to control reflectance of externally incident light. The reflective display device may improve the contrast ratio by controlling reflectance of a reflective area when an image is displayed.