Laser Illuminator Polarization Alignment

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional projectors require a polarization converter to align the polarization direction of illumination light with the polarizer axis, leading to increased size and cost due to the complexity and expense of this component.

Innovation Solution

An illuminator design incorporating multiple laser light sources for red, green, and blue light fluxes, with a light combiner and retardation films to align polarization directions, eliminating the need for a polarization converter by ensuring all light fluxes have aligned polarization downstream of the retardation films.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a polarization converter is used to align the polarization direction of illumination light with the polarizer axis, then the projector can display images through liquid crystal panels, but the size and cost of the illuminator increase

Engineering Contradiction:

Improveimage display capabilityVSAvoidilluminator size

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The invention extracts and eliminates the polarization converter component from the optical system by using three separate laser light sources with inherently aligned polarization directions, thereby reducing illuminator size while maintaining image display capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention makes each laser light source serve multiple functions: providing specific wavelength light (red, green, or blue) and simultaneously providing light with the correct polarization direction for the liquid crystal panel, eliminating the need for separate polarization conversion components

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

Engineering Contradiction:

Improveimage display capabilityVSAvoidilluminator cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention extracts and eliminates the expensive polarization converter component by using three separate laser light sources that inherently produce light with the correct polarization directions, thereby reducing illuminator cost while maintaining image display capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the expensive polarization converter with three relatively inexpensive laser light sources that can be easily manufactured and integrated, reducing overall system cost

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Productivity

If three laser light sources with different polarization directions are combined, then the light fluxes can be combined efficiently, but the polarization directions of the combined light fluxes are not aligned

Engineering Contradiction:

Improvelight combination efficiencyVSAvoidpolarization alignment

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The invention assigns different polarization directions to different wavelength bands (red, green, blue) based on their specific requirements, with each laser source providing light with the appropriate polarization for its wavelength, allowing efficient combination while maintaining proper polarization alignment for the liquid crystal panel

Inventive Principle:

Principle #3Local quality

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 reduces the projector's size and cost by eliminating the polarization converter while maintaining high image quality and minimizing speckle noise, achieving aligned polarization for the illuminator's light fluxes.

Implementation Method 1

a light combiner that combines the first, second, and third light fluxes with one another to produce combined light

Methodology Applied

Scientific EffectOptical interference: Interference

Implementation Method 2

a predetermined band retardation film that is provided on a downstream of the light combiner and changes a phase of a light flux that forms the combined light and belongs to the third wavelength band

Methodology Applied

Scientific EffectBirefringence: Birefringence

Data Source

PatentUS11190739B2Illuminator and projector

Publication Date: 2021.11.30 SEIKO EPSON CORP

AI summary

An illuminator includes a first laser light source section that outputs a first light flux that belongs to a first wavelength band, a second laser light source section that outputs a second light flux that belongs to a second wavelength band, a third laser light source section that outputs a third light flux that belongs to a third wavelength band and has a polarization direction different from those of the first and second light fluxes, a light combiner that combines the first, second, and third light fluxes to produce combined light, and a predetermined band retardation film on the downstream of the light combiner that changes the phase of a light flux that forms the combined light and belongs to the third wavelength band, and the polarization directions of the light fluxes contained in the combined light are aligned on the downstream of the predetermined band retardation film.