Backlight Module Prism Structure for Brightness

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Solution Overview

Problem

Backlight modules in electronic devices often suffer from poor efficiency, leading to reduced display brightness and increased power usage, as they fail to effectively distribute light to the user, with conventional designs not optimizing light angles for improved illumination.

Innovation Solution

The proposed backlight module incorporates a prism structure between the light guide and reflector, configured to change the angle of light reflection, increasing the emission of light at angles between 55 to 125 degrees, thereby enhancing display brightness and reducing total internal reflection, using materials like acrylic resin or polyethylene terephthalate for the prism film and a reflector with a high refractive index.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional backlight module designs are used, then the structure is simple, but the light distribution efficiency is poor and display brightness is reduced

Engineering Contradiction:
Improvedisplay brightnessVSAvoidbacklight module structure
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The reflector is segmented into multiple regions (first region, second region, third region) with different reflective properties and angular ranges. Each region is designed to reflect light within specific angular ranges (e.g., first region: 0-45 degrees, second region: 45-90 degrees, third region: 90-180 degrees), enabling optimized light distribution across different viewing angles while maintaining overall system functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the reflector are assigned different local optical properties. The first region has a first reflective property for narrow-angle reflection, the second region has a second reflective property for medium-angle reflection, and the third region has a third reflective property for wide-angle reflection. This local differentiation optimizes light extraction efficiency at each angular zone.

Inventive Principle:
Principle #3Local quality

2Loss of energy

If conventional reflector designs are used, then the manufacturing is simple, but total internal reflection is not effectively reduced

Engineering Contradiction:
Improvetotal internal reflection lossVSAvoidreflector fabrication
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The reflector is divided into multiple angular zones with distinct reflective characteristics. Each zone is engineered to address specific total internal reflection issues at different angles, systematically reducing energy loss across the entire angular spectrum rather than attempting a single-solution approach.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The solution transitions from considering only the vertical light path to incorporating angular dimension analysis. By designing reflector regions based on reflection angles (0-45°, 45-90°, 90-180°), the patent addresses total internal reflection losses in the angular dimension, enabling more comprehensive energy utilization.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If conventional light distribution is used, then the angular coverage is limited, but the light extraction efficiency is poor

Engineering Contradiction:
Improvelight extraction efficiencyVSAvoidangular control structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The reflector is segmented into three distinct angular regions, each optimized for specific reflection angles. This segmentation enables comprehensive coverage of the entire angular spectrum (0-180 degrees), maximizing the proportion of extracted light that reaches the display at optimal viewing angles.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent optimizes multiple parameters including reflective properties, angular ranges, and regional configurations of the reflector. By adjusting these parameters across different regions, the system achieves enhanced light extraction efficiency while maintaining practical manufacturability.

Inventive Principle:
Principle #35Parameter changes

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 configuration increases display brightness by up to 15% by optimizing light distribution and reducing reflections, improving the overall illumination of liquid crystal displays and other components.

Implementation Method 1

the prism structure is configured to change the angle of light reflected by the reflector to control the angle of light emitted from the top surface of the light guide

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

a reflector positioned below the light guide bottom surface and configured to reflect light incident on the light guide bottom surface

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

conventional designs not optimizing light angles for improved illumination

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP2685156B1Backlight module
Publication Date: 2020.11.11 BLACKBERRY LTD
  • EP2685156B1 patent drawingFigure 1
  • EP2685156B1 patent drawingFigure 2~3
  • EP2685156B1 patent drawingFigure 4

AI summary

A backlight module for illuminating a display is described. The backlight module may be provided in an electronic device along with a light source for illuminating an LCD display. The backlight module includes a diffuser, a light guide having a top surface and a bottom surface, a reflector, and a prism structure positioned between the light guide bottom surface and the reflector. The prism structure has a plurality of prisms extending towards the light guide. The prism structure may include a film or a top portion of the reflector having a plurality of prisms extending towards the light guide.