Backlight Module Light Guide Plate Tilted Entrance Surface

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Solution Overview

Problem

Existing backlight modules for liquid crystal display devices face issues with light leakage and increased width due to the design of the light guide plate, which causes hot lines and inefficient light distribution, and require additional space for the light emitting unit, making them unsuitable for narrow side frames.

Innovation Solution

The backlight module design features a light guide plate with a tilted light entrance surface relative to the light exit surface, incorporating a microstructure to enhance light incidence and a reflection cover that allows the light guide plate to abut tightly with the reflection cover, eliminating the need for additional containing space and reducing the module's width.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the light guide plate has a gradually-increased thickness to make the light entrance surface area greater than the light emitting area, then light use efficiency is improved, but a hot line problem and light leakage problem occur

Engineering Contradiction:

Improvelight use efficiencyVSAvoidhot line problem and light leakage problem

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating different thickness zones in the light guide plate. The first thickness is greater than the second thickness, forming a step structure that locally modifies light distribution. This prevents concentrated light leakage (hot lines) while maintaining overall light use efficiency, as the thicker region directs light properly and the thinner region prevents excessive light emission at edges.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The light guide plate is segmented into distinct thickness regions (first thickness and second thickness) rather than a gradual continuous increase. This segmentation creates discrete zones that control light propagation separately, preventing the formation of continuous hot lines while maintaining efficient light distribution across the display area.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If the backlight module includes an additional containing space between the light entrance surface and the reflection cover for containing the light emitting unit, then the light emitting unit can be properly positioned, but the overall width of the backlight module is increased

Engineering Contradiction:

Improvelight emitting unit positioningVSAvoidoverall width of backlight module

Core Design Contradiction:

Ease of operationVSLength of stationary object

Solution Approach 1:

The patent merges the light emitting unit directly with the light guide plate structure by eliminating the separate containing space. The light emitting unit is positioned adjacent to the light guide plate's light entrance surface without requiring additional containment structures, thereby integrating multiple functions into a compact configuration that reduces overall module width.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent repositions the light emitting unit to be disposed on the light entrance surface rather than in a separate containing space between the light entrance surface and reflection cover. This dimensional reorganization eliminates the need for additional width while maintaining proper positioning and optical functionality.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

This design improves light distribution and brightness while reducing the overall width of the backlight module, allowing for more efficient use of space and better integration into narrow liquid crystal display device frames.

Implementation Method 1

light emitted by the light emitting unit 14 is incident into the light guide plate 12 via the light entrance surface 18

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

light emitted by the light emitting unit 14 is incident into the light guide plate 12 via the light entrance surface 18 directly or by reflection of the reflection cover 16

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 3

The light emitting unit is disposed on the light entrance surface... An included angle is formed between the light entrance surface and the light exit surface

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS8899816B2Backlight module

Publication Date: 2014.12.02 AU OPTRONICS CORP

AI summary

A backlight module includes a light guide plate and a light emitting unit. The light guide plate has a first side surface, a second side surface, and a third side surface. The first side surface is located opposite to the second side surface. A height of the first side surface is greater than a height of the second side surface. The third side surface is located between the first side surface and the second side surface and has a light entrance surface and a light exit surface. The light entrance surface is connected to the first side surface and the light exit surface. The light exit surface is connected to the second side surface. An included angle is formed between the light entrance surface and the light exit surface. The light emitting unit is disposed on the light entrance surface.