Diffuse Reflection Polymer Film for High-Brightness E-Ink Displays

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Solution Overview

Problem

Current electronic paper display systems face challenges in achieving high-brightness diffuse reflection and satisfactory contrast ratios due to the use of vacuum coating processes, which are costly and result in low reflection ratios.

Innovation Solution

A reflection-type display structure with a high-brightness diffuse reflector is developed, utilizing a PET-based diffuse reflection polymer thin film material filled with particles, stacked under the substrate glass with an adhesive layer to enhance light transmission and reduce the light path, allowing for improved diffuse reflection and contrast, replacing the costly vacuum coating process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If vacuum coating process is used to create reflective surface, then mirror surface or reflection surface is formed, but manufacturing cost increases and reflection ratio decreases

Engineering Contradiction:
Improvemanufacturing costVSAvoidreflection ratio
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the fundamental parameter of the reflective surface from a vacuum-coated metallic layer to a polymer-based diffuse reflection structure. By using a polymer thin film with diffuse reflection particles embedded in it, the system achieves high reflection ratio (surpassing traditional paper's 80% reflection) while eliminating the need for expensive vacuum coating processes. This parameter change transforms the reflection mechanism from specular reflection to diffuse reflection, simultaneously improving manufacturability and reflection performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite material structure consisting of a polymer thin film (such as PET) embedded with diffuse reflection particles. This composite approach combines the optical scattering properties of the particles with the mechanical stability and flexibility of the polymer matrix, creating a reflective surface that achieves both high reflection ratio and ease of manufacture without requiring vacuum coating processes.

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If diffuse reflection material is placed under substrate glass, then diffuse reflection effect is improved, but light path distance increases reducing optical efficiency

Engineering Contradiction:
Improvediffuse reflection effectVSAvoidoptical efficiency
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent uses a thin polymer film as the diffuse reflection layer, which can be positioned close to the display layer while maintaining flexibility and optical transparency. The thin film structure minimizes the light path distance through the substrate glass, reducing energy loss while still providing effective diffuse reflection. The polymer film's thin nature allows it to be integrated into the display structure without significantly increasing the overall light path length.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent introduces an adhesive layer as an intermediary between the substrate glass and the diffuse reflection polymer thin film. This adhesive layer optimizes the optical coupling between components, ensuring efficient light transmission while maintaining the close proximity of the reflector to the display layer. The adhesive layer acts as a mediator that minimizes optical interference and energy loss in the light path.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 achieves a high diffuse reflection of up to 93% ambient light, significantly surpassing traditional paper's 80% reflection, while simplifying the manufacturing process and reducing costs, thereby providing a display effect similar to reading on paper with enhanced optical efficiency and durability.

Implementation Method 1

a reflector arranged under the substrate glass, the panel glass, wherein the display layer, the substrate glass and a diffuse reflection polymer thin film material are stacked in sequence, and the reflector is the diffuse reflection polymer thin film material

Methodology Applied
Scientific EffectDiffuse reflection: Reflection

Implementation Method 2

an adhesive layer arranged between the substrate glass and the diffuse reflection polymer thin film material and used for adhering the diffuse reflection polymer thin film material to the substrate side of the display structure, the optical property of the adhesive layer is adapted to transmit the incident light and emergent light to penetrate through the adhesive layer

Methodology Applied
Scientific EffectLight transmission: Refraction

Implementation Method 3

The EFD is also called as electrowetting display, where the electrowetting refers to a phenomenon that the wettability of droplets on the substrate is changed, i.e., a contact angle is changed to deform and shift the droplets, by varying a voltage between the droplets and the insulating substrate

Methodology Applied
Scientific EffectElectrowetting: Electrowetting

Data Source

PatentEP3136135B1Display structure having high-brightness diffuse reflector and manufacturing method therefor
Publication Date: 2020.05.13 SHENZHEN GUOHUA OPTOELECTRONICS CO LTD
  • EP3136135B1 patent drawingFigure 1~3
  • EP3136135B1 patent drawingFigure 4

AI summary

A display structure having a high-brightness diffuse reflector, and an electrowetting display structure based on the display structure, an in-cell type electrowetting display structure and a manufacturing method thereof. The display structure comprises panel glass (1), a display layer (2) and substrate glass (3), wherein a high-brightness diffuse reflection polymer thin film material (4) is arranged under the substrate glass (3); the panel glass (1), the display layer (2), the substrate glass (3) and the diffuse reflection polymer thin film material (4) are stacked in sequence. According to the display structure and manufacturing method thereof of the invention, the required diffuse reflection and contrast ratio approximate to paper can be provided by placing a high-brightness diffuse reflection polymer thin film under a substrate or a display layer of a plate display structure as a diffuse reflection layer or a diffuse reflector. The process of the invention is simpler compared with vacuum coating process which can be avoided, thereby greatly reducing the manufacturing cost.