Switchable Transparent Electrowetting Display with Segmented Liquid Layers
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Solution Overview
Problem
Conventional electrowetting display devices lack the ability to provide a transparent display effect and have poor contrast ratio due to their inability to control transparency and grey scale values independently in different sub-pixel regions.
Innovation Solution
A switchable transparent electrowetting display device is designed with an electrowetting display panel and a light-emitting unit, featuring multiple sub-pixel regions with optical color-converting liquid layers and light-shielding liquid layers, allowing for independent control of transparency and grey scale values through voltage adjustments, enabling switchable display modes including transparent, non-transparent, and semi-transparent modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional electrowetting display device uses single liquid layer structure, then device structure is simple, but transparency control and grey scale control cannot be performed independently in different sub-pixel regions
Solution Approach 1:
The display device is divided into multiple independent liquid layers (first liquid layer with color-converting particles and second liquid layer as light-shielding layer) and multiple electrode systems (first electrodes for grey scale control and second electrodes for transparency control). This segmentation allows independent control of transparency and grey scale values in different sub-pixel regions, resolving the contradiction between adaptability and structure complexity.
Solution Approach 2:
The first liquid layer serves multiple functions: it provides color conversion through particles and enables grey scale control through voltage application. The second liquid layer provides light-shielding function for transparency control. This multi-functionality design allows the device to achieve independent control of transparency and grey scale without requiring completely separate systems, thus managing structure complexity while improving adaptability.
2Illumination intensity
If conventional electrowetting display device allows white light to pass through without ink layers, then aperture ratio is high, but contrast ratio is poor because dark images are not black enough
Solution Approach 1:
The second liquid layer is configured to selectively cover different sub-pixel regions (red, green, blue sub-pixels) with light-shielding properties. This local quality control allows the device to block light in specific regions where dark images are displayed, improving contrast ratio without affecting light transmission in other regions, thus resolving the contradiction between contrast ratio and light transmission efficiency.
3Ease of manufacture
If conventional electrowetting display device uses hydrophobic dielectric layer with polarized water solution, then electrowetting effect is achieved, but transparent display effect cannot be provided
Solution Approach 1:
The device uses a composite liquid layer structure where the first liquid layer contains color-converting particles suspended in polarized water solution with hydrophobic dielectric layer, and the second liquid layer contains light-shielding particles. This composite material design maintains the electrowetting effect while enabling transparent display mode capability, resolving the contradiction between ease of manufacture and adaptability.
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 device achieves improved contrast ratio and flexible display modes by precisely controlling the position and energy state of liquid layers and light-shielding layers, enhancing the display capabilities of electrowetting technology.
Implementation Method 1
a light-emitting unit (80) for providing a light source (L1) to the electrowetting display panel (60)
Implementation Method 2
a first optical color-converting liquid layer (741) disposed on the first electrode (68) and corresponding to the first sub-pixel region (661) for providing a first color light (LR) in the first sub-pixel region (661), and a second optical color-converting liquid layer (742) disposed on the first electrode (68) and corresponding to the second sub-pixel region (662) for providing a second color light (LG) in the second sub-pixel region (662)
Implementation Method 3
When a voltage source (28) provides a voltage between the transparent electrode (25) and the polarized water solution (23), the surface tension between the hydrophobic dielectric layer (24) and the polarized water solution (23) is modulated such that the locations of the ink layers (27) can be controlled
Data Source
AI summary
An electrowetting display device includes an electrowetting display panel and an illumination unit. The electrowetting display panel includes two or more different optical color-converting liquid layers and a plurality of light-shielding liquid layers. The two or more different optical color-converting liquid layers are able to convert the light source generated by the illumination unit into light beams having two or more different colors of desired grey scales. The light-shielding liquid layers can be driven to change the transmittance of display regions so as to implement switch between transparent display mode, non-transparent display mode and semi-transparent display mode.