Specular Partial Reflector Backlight for LC Display

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Solution Overview

Problem

Current liquid crystal (LC) display backlights inefficiently utilize polarized light, as they rely on randomization processes that waste light and diminish its intensity with each recycling cycle, leading to suboptimal illumination of LC panels.

Innovation Solution

Incorporating a specular partial reflector between the illumination device and a circular-mode reflective polarizer in the backlight, which deterministically transforms orthogonal polarized light into transmittable polarized light, enhancing light recycling and delivery to the LC panel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If randomization processes are used to recycle polarized light in the backlight, then light recycling is achieved, but light intensity is wasted and diminished with each recycling cycle

Engineering Contradiction:

Improvelight intensityVSAvoidbacklight efficiency

Core Design Contradiction:

Loss of energyVSProductivity

Solution Approach 1:

The patent replaces randomization processes with a deterministic polarization transformation system consisting of a specular partial reflector and a circular-mode reflective polarizer. This deterministic optical system systematically transforms orthogonal polarized light into transmittable polarized light, eliminating the intensity loss inherent in random recycling methods while maintaining efficient light circulation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the polarization state parameter of light through the circular-mode reflective polarizer, which converts orthogonal polarized light into a transmittable state. This parameter transformation allows light to be recycled without intensity loss, as the light systematically changes its polarization property rather than being randomly scattered.

Inventive Principle:

Principle #35Parameter changes

2Illumination intensity

If conventional backlights are used, then light sources illuminate the LC panel, but polarized light is inefficiently utilized leading to suboptimal illumination

Engineering Contradiction:

Improvedisplay brightnessVSAvoidpolarized light utilization efficiency

Core Design Contradiction:

Illumination intensityVSProductivity

Solution Approach 1:

The patent implements a feedback mechanism where light that is reflected by the circular-mode reflective polarizer is redirected by the specular partial reflector back to the polarizer for further transformation. This closed-loop system continuously recycles and transforms polarized light, maximizing its utilization and maintaining high illumination intensity without waste.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces inefficient conventional light management with a deterministic polarization transformation system that actively manages and optimizes polarized light utilization, thereby maximizing display brightness while improving the efficiency of polarized light usage.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 significantly improves backlight efficiency by maximizing the transmission of pass-polarized light to the LC panel, minimizing waste, and maintaining light intensity through deterministic polarization transformation, thereby enhancing display brightness and performance.

Implementation Method 1

a specular partial reflector. The specular partial reflector is disposed between the illumination device and the circular-mode reflective polarizer

Methodology Applied

Scientific EffectSpecular reflection: Reflection

Implementation Method 2

a circular-mode reflective polarizer. The circular-mode reflective polarizer is configured to transmit a first portion of light having a first circular polarization and reflect a second portion of light having a second circular polarization orthogonal to the first circular polarization

Methodology Applied

Scientific EffectCircular polarization filtering: Polarisation

Data Source

PatentUS9488859B2Backlighting system including a specular partial reflector and a circular-mode reflective polarizer

Publication Date: 2016.11.08 3M INNOVATIVE PROPERTIES CO

AI summary

A backlight that includes an illumination device that has at least one light source, a circular-mode reflective polarizer, and a specular partial reflector is disclosed. The specular partial reflector is disposed between the illumination device and the circular-mode reflective polarizer. Furthermore, the specular partial reflector is in substantially direct polarization communication with the circular-mode reflective polarizer.