Bent Light Guide Plates for Flexible Screen Backlight Uniformity

Solution Overview

Problem

Flexible electronic devices with flat light guide plates in backlight modules experience non-uniform backlight brightness due to bright lines formed at their junctions when expanded or folded, affecting the overall quality of the screen.

Innovation Solution

The design incorporates pivotally connected light guide plates with bent portions that adjust their position relative to a housing unit, allowing the bent ends to face away from the screen, reducing light emission and preventing bright lines, and includes a diffusion structure and function layer for uniform light distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If flat light guide plates are used in backlight modules, then the structure is simple and easy to manufacture, but bright lines are produced at the junctions when the flexible screen is expanded, resulting in non-uniform backlight brightness

Engineering Contradiction:

Improveease of manufactureVSAvoidbacklight brightness uniformity

Core Design Contradiction:

Ease of manufactureVSIllumination intensity

Solution Approach 1:

The light guide plates are designed with bent portions instead of flat surfaces. The bent portions extend curvedly from the inner side of the plate body into the base, causing the end faces to face away from the flexible screen. This curvature modification prevents light from being emitted toward the screen at the junctions, eliminating bright lines while maintaining manufacturing feasibility through standard bending processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Illumination intensity

If two backlight modules are connected to provide backlight to the flexible screen, then the screen can be illuminated when expanded, but bright lines are easily produced at the junction of the light guide plates, affecting overall backlight quality

Engineering Contradiction:

Improvebacklight brightnessVSAvoidbacklight quality uniformity

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The light guide plates are designed with different local properties: the plate body provides light guidance, while the bent portions specifically address the junction area by directing light away from the screen. This localized modification at the bent portions eliminates bright lines at critical junction areas without affecting the overall backlight performance, ensuring uniform illumination across the entire flexible screen.

Inventive Principle:

Principle #3Local quality

3Device complexity

If the light guide plates are disposed flatly, then the manufacturing process is simple, but the end faces emit more light toward the flexible screen, producing bright lines at junctions

Engineering Contradiction:

Improvedevice complexityVSAvoidbright lines at junctions

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The light guide plates are designed with bent portions instead of flat surfaces. The bent portions extend curvedly from the inner side of the plate body into the base, causing the end faces to face away from the flexible screen. This curvature modification prevents light from being emitted toward the screen at the junctions, eliminating bright lines while maintaining manufacturing feasibility through standard bending processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS8833999B2Electronic device having a flexible screen, a backlight module and a light guide plate

Publication Date: 2014.09.16 WISTRON CORP

AI summary

An electronic device includes a base having two opposite sidewalls, two carriers connected pivotally and respectively to the sidewalls, and two light guide plates respectively disposed on the carriers. The carriers are rotatable relative to the base between a first position, where the carriers cooperatively define a carrier surface, and a second position, where the carriers are parallel to each other. A flexible screen is superposed on the light guide plates, is expanded to a planar state when move along with the carriers to the first position, and is folded when move along with the carriers to the second position.