Color Electrophoretic Display Waveform Generation Without Dithering

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Solution Overview

Problem

Conventional methods for displaying full-color images on color electrophoretic displays rely on spatial dithering, which requires significant computational power, increases manufacturing costs, and can be ineffective at certain viewing distances.

Innovation Solution

The method involves generating waveforms with a multi-transition structure that are not prior state dependent, allowing for the creation of colors at each pixel that map to the corresponding pixel in the original image without the use of dithering. This is achieved by selecting seed candidate waveforms based on optical measurements and applying perturbation waveforms to transition the optical state of the display pixels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If spatial dithering is used to display full-color images on color electrophoretic displays, then color representation capability is improved, but computational power requirements and manufacturing costs increase

Engineering Contradiction:

Improvecolor representation capabilityVSAvoidcomputational power requirements

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the color display problem by using multiple sub-pixels within each pixel, where each sub-pixel can independently display one of a limited set of palette colors. By combining different palette colors in adjacent sub-pixels, the display achieves full-color capability without requiring complex computational rendering at each pixel location.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from spatial dithering (mixing colors across adjacent pixels) to sub-pixel dithering (mixing colors within a single pixel through multiple sub-pixels). This dimensional change from pixel-level to sub-pixel-level color mixing reduces the computational burden while maintaining color accuracy.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If spatial dithering is used to create colors outside the color gamut, then color accuracy is improved, but effectiveness decreases at certain viewing distances

Engineering Contradiction:

Improvecolor accuracyVSAvoideffectiveness at various viewing distances

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

By dividing each pixel into multiple sub-pixels, the patent enables color mixing to occur at a finer spatial scale. This segmentation allows the human eye to perceive averaged colors from multiple sub-pixels as a single uniform color, maintaining color accuracy even when viewed from distances where individual sub-pixels are not clearly distinguishable.

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If conventional spatial dithering methods are used, then color gamut expansion is achieved, but device power consumption and manufacturing costs increase

Engineering Contradiction:

Improvecolor gamutVSAvoiddevice power consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent pre-defines a limited palette of colors that can be displayed by individual sub-pixels. By preparing these palette colors in advance and combining them through simple additive mixing, the system achieves expanded color gamut without requiring complex real-time computational rendering, thereby reducing power consumption.

Inventive Principle:

Principle #10Preliminary action

4Manufacturing precision

If spatial dithering is implemented with increased computational power, then image rendering quality is improved, but manufacturing costs increase

Engineering Contradiction:

Improveimage rendering qualityVSAvoidmanufacturing costs

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent simplifies the rendering process by segmenting color display into predefined palette colors at the sub-pixel level. This segmentation allows for simpler, more cost-effective manufacturing compared to implementing full spatial dithering algorithms, while still achieving high image rendering quality through the combination of multiple sub-pixel colors.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250191547A1Method of driving a color electophoretic display to form images without dithering

Publication Date: 2025.06.12 E INK CORP

AI summary

A method for creating waveforms having a multi-transition structure for driving color electrophoretic displays is described. The method includes generating a set of seed candidate waveforms, and applying each seed candidate waveform to the display pixels of the color electrophoretic display. The method includes measuring the optical state of each color created at the display pixels by applying the seed candidate waveforms, and selecting a set of seed waveforms based on the optical measurements of the colors produced by applying each seed candidate waveform. The method also includes generating a first sequence of perturbation waveforms, and applying each perturbation waveform of the first sequence of perturbation waveforms to each seed waveform of the color electrophoretic display. The method also includes measuring the optical state of each color created at the display pixels by applying each perturbation waveform of the first sequence to each seed waveform.