Light Source Device with Segmented Optical Element for Cost Reduction

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Solution Overview

Problem

The high cost of light source devices for projectors is attributed to the expensive crystal quartz used in quarter wave plates, which are necessary for polarization separation and combining processes.

Innovation Solution

A light source device design that includes a first optical element with distinct areas for transmitting and reflecting light, a second optical element for converting light into circularly-polarized light, and a wavelength conversion element, which reduces the need for large crystal quartz wave plates by downsizing them and optimizing light path usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If quarter wave plates are made using crystal quartz to achieve polarization separation and combining, then the polarization control function is improved, but the manufacturing cost increases significantly

Engineering Contradiction:

Improvepolarization control functionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent divides the optical system into multiple functional areas within a single optical element. The light separation and combining element is segmented into a first area for transmitting first light and a second area for reflecting first light, eliminating the need for separate quarter wave plates while maintaining polarization control functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent merges the functions of polarization separation, light direction control, and wavelength conversion into a single integrated optical system. The light separation and combining element combines multiple optical functions that were previously performed by separate components including quarter wave plates, reducing both component count and manufacturing cost.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If multiple separate optical components are used for polarization separation and light conversion, then the optical function completeness is improved, but the device complexity increases

Engineering Contradiction:

Improveoptical function completenessVSAvoidnumber of optical components

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The light separation and combining element is designed as a multi-functional optical component that simultaneously performs polarization separation, light direction control, and works with the wavelength conversion element. This universal component replaces multiple specialized optical elements, reducing device complexity while maintaining complete optical functionality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements a nested optical path structure where the second optical element is positioned to receive light from the first area of the light separation and combining element, and the wavelength conversion element is integrated into the optical path. This nested arrangement allows multiple optical functions to be performed in a compact, organized manner.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 overall cost of the light source device and projector by minimizing the use of expensive crystal quartz while maintaining effective polarization separation and light conversion, allowing for adjustable white balance and improved image quality.

Implementation Method 1

a second optical element into which the first light output from the first area of the first optical element is entered, converting the first light into a circularly-polarized second light having the first wavelength

Methodology Applied

Scientific EffectPolarization conversion: Polarisation

Implementation Method 2

a diffuser element into which the second light output from the second optical element is entered

Methodology Applied

Scientific EffectLight diffusion: Diffusion

Implementation Method 3

a wavelength conversion element into which the first light output from the second area of the first optical element is entered

Methodology Applied

Scientific EffectWavelength conversion: Fluorescence

Data Source

PatentUS11333960B2Light source device and projector in which wave plates are downsized

Publication Date: 2022.05.17 SEIKO EPSON CORP

AI summary

A light source device of the present disclosure includes a light emitting device, a first optical element having a first area and a second area, a second optical element converting a first light output from the first area into a second light, a diffuser element into which the second light is entered, and a wavelength conversion element into which the first light output from the second area is entered. The light output from the diffuser element and entered into the second optical element is converted into a third light, the third light output from the second optical element and entered into the first area is output from the first area, the light output from the diffuser element and entered into the second area is output from the second area, and a fourth light is output through the first area and the second area.