Electro-optical Apparatus with Electrode Surface Roughness for Reflective Display Contrast
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Solution Overview
Problem
Existing electro-optical apparatus using electrochromic materials face challenges in achieving high visibility as a reflective display due to low contrast between display and non-display areas, particularly when trying to maintain a transparent state without hindering the field of view.
Innovation Solution
The apparatus is configured with a first electrode having fine irregularities and a second electrode with nano-order surface roughness, allowing for the switching between white, black, and transparent states by controlling the deposition of metal films using a driving voltage, enabling superior image visibility and maintaining transparency when not in use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a scattering plate is disposed behind one of the transparent substrates to scatter light transmitted through the non-display portion, then the contrast is improved, but the transparent state cannot be obtained and the device complexity increases
Solution Approach 1:
The patent applies local quality by providing fine irregularities only on the surface of the electrode in the non-display portion, while keeping the display portion with a smooth electrode surface. This localized structural differentiation enables the non-display area to scatter light (improving contrast) while the display area maintains transparency, eliminating the need for additional scattering plates and reducing device complexity.
2Illumination intensity
If a silver film is deposited on the electrode having fine irregularities in the non-display portion, then the black display is achieved, but the contrast becomes low due to the transparent periphery
Solution Approach 1:
The patent implements local quality by creating fine irregularities specifically on the electrode surface in the non-display portion, while maintaining a smooth surface in the display portion. When silver film is deposited on the irregular surface, light is scattered creating a black appearance, whereas the smooth display portion remains transparent. This localized surface structure differentiation achieves high contrast without compromising display intensity.
3Quantity of substance
If the electrode surface is made smooth for transparent state, then the transparency is improved, but the contrast in display mode deteriorates
Solution Approach 1:
The patent resolves this contradiction by applying local quality - the electrode surface is made smooth in the display portion to maintain transparency when needed, while the non-display portion has fine irregularities to provide scattering and contrast. This spatial differentiation of surface properties allows the system to achieve both high transparency and high contrast in their respective functional areas simultaneously.
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 allows for enhanced image visibility and flexibility in display states, ensuring high contrast and unobstructed viewing angles, making it suitable for applications like digital signage and head-up displays.
Implementation Method 1
when a metal film is deposited on the first electrode, the incident light is scattered by the fine irregularities, creating a white state in appearance
Implementation Method 2
when a metal film is deposited on the smooth surface electrode, the surface of the electrode becomes a mirror face state and reflects the incident light
Implementation Method 3
When a voltage is applied between the electrodes, silver ions in the electrolyte layer are reduced at one electrode and deposits a silver film
Implementation Method 4
an electro-optical apparatus configured using an electrochromic material
Data Source
Figure 1
Figure 2A~2C
Figure 3~4B
AI summary
To provide an electro-optical apparatus suitably usable as a reflective display apparatus with excellent visibility. A first substrate having a first electrode on one surface side, a second substrate having a second electrode on one surface side and arranged opposing the first substrate, an electrolyte layer having material used for electrolytic deposition and disposed between the first electrode and the second electrode are included. Each of the first electrode and the second electrode has a concave-convex configuration on one surface side that is in contact with the electrolyte layer. Surface roughness Ra of one side of the first electrode is 0.4 µm or more, and surface roughness Ra of one surface side of the second electrode is 0.02µm or more and relatively smaller than the surface roughness of the first electrode.