Backlight Lens for Uniform Lighting

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Solution Overview

Problem

Backlights suffer from non-uniform lighting issues due to insufficient light incident on the light guide panel and hot or dark spots caused by the angle of light incidence, leading to unintended bright or dark spots in display devices.

Innovation Solution

Incorporating a lens that increases the average angle of incidence of light emitted from the light emitting element relative to the major surface of the light guide plate, focusing light into collimated beams and redirecting it using a contour of the receiving and transmission surfaces to improve light distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If light is emitted directly from the light emitting element onto the light guide plate, then the structure is simple, but the lighting uniformity is poor due to insufficient light incident and hot/dark spots caused by angle of incidence

Engineering Contradiction:
Improvelighting uniformityVSAvoidbacklight structure complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

A lens is introduced as an intermediary component between the light emitting element and the light guide plate. The lens receives light from the light emitting element and redirects it onto the light guide plate, improving lighting uniformity by controlling the angle of incidence while maintaining reasonable structural complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The lens changes the angular parameter of incident light by refracting it at specific angles. By controlling the angle of incidence through the lens design, the lighting uniformity is improved as hot and dark spots are eliminated, while the structural complexity remains manageable

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the angle of incidence of light on the light guide plate is not optimized, then the structure is simple, but diffraction inefficiencies occur causing hot and dark spots

Engineering Contradiction:
Improvelight coupling efficiencyVSAvoidoptical path structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The lens serves as a mediator that optimizes the angle of incidence before light enters the light guide plate. This intermediary component ensures efficient light coupling by directing light at appropriate angles, reducing diffraction inefficiencies without requiring complex optical paths

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The lens performs preliminary action by pre-adjusting the angle of incidence of light before it reaches the light guide plate. This preliminary optimization of light direction prevents diffraction inefficiencies and hot/dark spots from occurring, improving reliability while keeping the overall structure relatively simple

Inventive Principle:
Principle #10Preliminary action

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 enhances light uniformity across the display, reducing diffraction inefficiencies and hot spots, resulting in improved image quality by ensuring more efficient coupling of light from the light guide to the display.

Implementation Method 1

a lens configured to increase an average angle of incidence of light emitted from a light emitting element of the backlight

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

The non-uniform lighting can be caused by insufficient light incident on a light guide panel (LGP) of the backlight

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3839337B1Improved edge coupled lighting collimation for backlight
Publication Date: 2024.10.23 LUMILEDS HLDG BV
  • EP3839337B1 patent drawingFigure 1
  • EP3839337B1 patent drawingFigure 2
  • EP3839337B1 patent drawingFigure 3

AI summary

The invention describes a backlight apparatus (400) comprising: a backplate (102); a light emitting element (30) located within the backplate (102) and configured to emit visible light; a lens (302) located within the backplate (102) and configured to angularly redirect the visible light into a batwing configuration of first and second collimated light beams (308, 310), the lens (302) including a concave receiving surface (304) facing the light emitting element and a transmission surface (305) opposing the receiving surface (305), the transmission surface (305) including an angle of curvature that increases closer to a plane of symmetry (306) of the lens; and a light guide panel (20) configured to distribute light from the first and second collimated light beams (306, 310) to a surface (52) of the light guide panel (20) facing a display device (40). The invention further describes a method of manufacturing such a backlight apparatus.