Backlight Module Light Guide Plate Overlapping Reflective Structures

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional backlight modules for liquid crystal displays suffer from low light utilization ratios, leading to the need for additional or high-powered light sources, which increase power consumption, heat generation, and manufacturing costs.

Innovation Solution

A backlight module featuring a light guide plate with partially overlapping reflective structures on its bottom surface, designed to optimize light emission by ensuring that light beams enter the light guide plate with angles less than the critical angle, thereby reducing propagation distances and enhancing light utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a planar and smooth bottom surface is used in the light guide plate, then the manufacturing process is simple, but the light utilization ratio is low

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidlight utilization ratio

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The bottom surface of the light guide plate is segmented into multiple reflective structures (reflective ridges or reflective dots) arranged in arrays, rather than being a single planar surface. This segmentation creates multiple reflection points that redirect light at optimal angles, improving light extraction efficiency while maintaining manufacturing feasibility through injection molding or similar processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bottom surface transitions from uniform planar quality to localized reflective structures with specific geometries. Each reflective structure is designed with particular shapes (ridges or dots) and arrangements that create localized optical effects, directing light beams at controlled angles to exceed the critical angle for total internal reflection, thereby improving light utilization in specific regions.

Inventive Principle:

Principle #3Local quality

2Illumination intensity

If more light sources or high-powered light sources are used to achieve desired brightness, then the light output brightness is improved, but the power consumption and heat generation increase

Engineering Contradiction:

Improvelight output brightnessVSAvoidpower consumption

Core Design Contradiction:

Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent converts the harmful effect of light loss through total internal reflection into a beneficial effect by designing reflective structures that intentionally create reflections exceeding the critical angle. What would normally be considered light loss (total internal reflection) is transformed into useful light output by strategically positioning reflective structures to redirect light beams that would otherwise be trapped, thereby improving overall light utilization without requiring additional power input.

Inventive Principle:

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

3Illumination intensity

If more light sources are added to improve brightness, then the light output is improved, but the manufacturing cost increases

Engineering Contradiction:

Improvelight output brightnessVSAvoidmanufacturing cost

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The reflective structures on the bottom surface serve multiple functions simultaneously: they act as light redirectors, angular controllers, and extraction enhancers. By integrating these reflective structures directly into the light guide plate substrate, the design eliminates the need for separate components, reducing part count and assembly complexity while achieving improved light output efficiency.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 improves the optical performance of liquid crystal displays by increasing the light utilization ratio, eliminating the need for additional or high-powered light sources, and reducing manufacturing costs.

Implementation Method 1

Other light beams reaching the light emitting surface 113 are totally reflected by the light emitting surface 113, because the angles of incidence of these light beams are greater than the critical angle

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

Some of the light beams reaching the light emitting surface 113 are refracted by the light emitting surface 113, because the angles of incidence of these light beams are less than a critical angle of light beams at the light emitting surface 113

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS7898615B2Backlight module with light guide plate having partially overlapped reflective structures and liquid crystal display with same

Publication Date: 2011.03.01 RED OAK INNOVATIONS LTD

AI summary

An exemplary backlight module includes a light source and a light guide plate. The light guide plate includes a light incident surface positioned for receiving light beams from the light source, a bottom surface adjacent to the light incident surface, reflective structures provided on the bottom surface, and a light emitting surface configured for emission of the light beams. Each of the reflective structures partially overlaps corresponding adjacent reflective structures at one side, and is partially overlapped by corresponding adjacent reflective structures at an opposite side. A liquid crystal display including the backlight module is also provided.