Air Gap Front-Light Module for Reflective Display Contrast

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Electronic book readers with color filters suffer from reduced optical energy efficiency and darker image display when showing colored images due to the need for ambient light to pass through the filter twice, leading to lower contrast ratio and color saturation compared to monochrome images.

Innovation Solution

Incorporating a front-light module with a light guide plate, a light source, and a cover lens, where the light guide plate has a first light guide surface with a light outgoing region and a peripheral region separated by an air gap from the cover lens, which reduces noise light and enhances the signal-to-noise ratio, thereby improving contrast ratio and color saturation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a color filter is disposed on a reflective display panel to show colored images, then the display can present colored images, but the optical energy efficiency is significantly reduced and the image appears darker

Engineering Contradiction:

Improvecolor display capabilityVSAvoidoptical energy efficiency

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The light guide plate is segmented into a light outgoing region and a peripheral region, with the peripheral region connected to the cover lens and the light outgoing region forming an air gap with the cover lens. This segmentation allows different regions to serve different functions: the peripheral region guides light while the air gap region reduces noise light, thereby improving optical energy efficiency while maintaining color display capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An air gap is introduced as an intermediary between the light guide plate and the cover lens. This air gap acts as a mediator that reduces noise light while allowing signal light to pass through, improving the signal-to-noise ratio and optical energy efficiency without compromising the color image quality

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If ambient light passes through the color filter twice to display colored images, then the color filter can control wavelength ranges, but the contrast ratio and color saturation are reduced

Engineering Contradiction:

Improvewavelength selection capabilityVSAvoidcontrast ratio and color saturation

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The harmful noise light is extracted and eliminated by the air gap structure between the light guide plate and cover lens. By removing the noise light component, the signal-to-noise ratio is improved, thereby enhancing contrast ratio and color saturation while preserving the wavelength selection capability of the color filter

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The air gap structure converts the potentially harmful noise light into a beneficial element by using total internal reflection at the air gap interface to redirect noise light away from the viewer's eye, while allowing signal light to pass through. This transforms the harmful noise light into a mechanism for improving image quality

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 air gap reduces noise light, leading to improved contrast ratio and color saturation by minimizing energy loss and enhancing the display's ability to show colored images with increased brightness and clarity.

Implementation Method 1

a light guide plate (200)... The light guide plate includes a first light guide surface (210) opposite to the reflective display module (100)

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

The light outgoing region and the cover lens (400) are spatially separated, and define an air gap (500) therebetween

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 3

the air gap (500) can reduce the noise light (L2)

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 4

the sub-pixel region of the color filter absorbs the light in a particular range of wavelength

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS9329327B2Display and front-light module thereof

Publication Date: 2016.05.03 E INK HLDG INC

AI summary

A display includes a reflective display module, a light guide plate, at least one light source and a cover lens. The light guide plate includes a first light guide surface opposite to the reflective display module. The first light guide surface includes a light outgoing region and a peripheral region surrounding the light outgoing region. The light source is used for emitting a light to the light guide plate. The peripheral region of the first light guide surface is connected to the cover lens. The light outgoing region and the cover lens are spatially separated, and define an air gap therebetween.