Hybrid Projector Light Source Layout for Brightness and Color Uniformity

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Solution Overview

Problem

Projector apparatuses face challenges with lamp-based light sources having short lifespans and high replacement costs, LED sources offering lower brightness, and laser diodes increasing product size and manufacturing costs, while using both leads to brightness and color inconsistencies.

Innovation Solution

A hybrid optical system combining LEDs and laser diodes as light sources, utilizing specific wavelength dichroic mirrors and phosphors to optimize brightness and color uniformity, with LEDs positioned closer to the lens and laser diodes further away to minimize size and brightness differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a lamp is used as a light source, then high brightness can be achieved, but the life of the lamp is short and components need to be frequently replaced

Engineering Contradiction:
ImprovebrightnessVSAvoidlamp life
Core Design Contradiction:
Illumination intensityVSDuration of action of stationary object

Solution Approach 1:

The patent segments the light source system into multiple LED chips with different wavelengths (red, green, blue) to replace the single lamp system. This allows the system to achieve high brightness through combined output while maintaining the long lifespan of LED components, resolving the contradiction between brightness and durability.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If LED is used as a light source, then component size and manufacturing cost are reduced, but the overall brightness of the output image is lowered

Engineering Contradiction:
Improvecomponent sizeVSAvoidbrightness
Core Design Contradiction:
Device complexityVSIllumination intensity

Solution Approach 1:

The patent merges multiple LED light sources with different wavelengths (red LED at 630-680nm, green LED at 520-560nm, blue LED at 450-490nm) into a single hybrid optical system. This combination achieves high overall brightness comparable to traditional lamps while maintaining the compact size and low cost advantages of LED technology.

Inventive Principle:
Principle #5Merging (Combining)

3Illumination intensity

If laser diode is used as a light source, then the brightness of the output image is high, but the product size increases and the manufacturing cost increases

Engineering Contradiction:
ImprovebrightnessVSAvoidproduct size
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent segments the high-brightness requirement into three separate LED light sources with different wavelengths, each contributing to specific color channels. This segmentation allows the system to achieve high overall brightness through combined output while avoiding the size and cost penalties of using laser diodes for all color channels.

Inventive Principle:
Principle #1Segmentation

4Productivity

If both LED and laser diode are used as light sources, then advantages of both can be maximized, but brightness and color inconsistencies occur

Engineering Contradiction:
Improvesystem performanceVSAvoidbrightness uniformity
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by assigning specific wavelength ranges to specific LED types (red: 630-680nm, green: 520-560nm, blue: 450-490nm) and using dichroic mirrors to selectively direct each wavelength to its designated color channel. This localized optimization ensures consistent brightness and color reproduction across all channels while maintaining the performance benefits of hybrid LED technology.

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

The hybrid system maximizes the advantages of both LED and laser diode light sources, reducing component count, simplifying internal configuration, and minimizing brightness and color discrepancies, thus enhancing overall performance and reducing product size.

Implementation Method 1

a green phosphor that converts the fourth light into a fifth light

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 2

a first dichroic mirror reflecting the first light; a second dichroic mirror reflecting the second light; and a third dichroic mirror reflecting the third light and the fourth light

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4212954B1Optical system comprising hybrid light source, and projector device comprising same
Publication Date: 2026.01.28 LG ELECTRONICS INC
  • EP4212954B1 patent drawingFigure 1
  • EP4212954B1 patent drawingFigure 2
  • EP4212954B1 patent drawingFigure 3

AI summary

The present disclosure relates to an optical system composed of a hybrid light source, and the optical system includes a first red light emitting diode (LED) emitting a first light of a first wavelength; a second red LED emitting a second light of a second wavelength; a blue LED emitting a third light of a third wavelength; a blue laser diode emitting a fourth light of the third wavelength; and a green phosphor converting the fourth light into a fifth light of a fourth wavelength, in which the first light, the second light, the third light, and the fifth light are emitted in a first direction.