Light Emitting Device Lens Array Pitch Optimization

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Solution Overview

Problem

Existing light emitting devices for image display systems face issues with intensity unevenness and diffraction due to misalignment of components, leading to reduced detection accuracy and increased assembly complexity.

Innovation Solution

The use of an optical element comprising small lenses with an array pitch set within a predetermined numerical range based on the focal distance of the collimator, ensuring that the array pitch is between 0.638 times the wavelength and 124.8 times the angular width of the light source, prevents diffraction and intensity unevenness, maintaining a stable light emission state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the array pitch of lenses is reduced to decrease device size, then device size is reduced, but diffraction occurs and interference patterns appear

Engineering Contradiction:
Improvedevice sizeVSAvoiddiffraction and interference patterns
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by establishing a specific numerical relationship between the array pitch P and the focal distance f (0.638λ ≤ P ≤ 124.8W, where λ is wavelength and W is angular width). This parameter optimization prevents diffraction and interference patterns while maintaining reduced device size, resolving the contradiction between miniaturization and optical quality.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the array pitch is made finer to reduce intensity unevenness due to assembly accuracy, then intensity unevenness is reduced, but diffraction occurs and interference patterns appear

Engineering Contradiction:
Improveintensity uniformityVSAvoiddiffraction and interference patterns
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent resolves this contradiction by defining an optimal parameter range for array pitch P (0.638λ ≤ P ≤ 124.8W) that simultaneously achieves fine intensity uniformity and prevents diffraction. This parameter optimization allows the system to benefit from finer array pitch without encountering the harmful diffraction effects.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a single Powell lens is used to collimate light, then assembly is simpler, but misalignment causes conspicuous intensity unevenness

Engineering Contradiction:
Improveassembly complexityVSAvoidintensity uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies segmentation by dividing a single Powell lens into multiple small lenses arranged in an array. This segmentation reduces the impact of misalignment on intensity uniformity while the optimized array pitch prevents diffraction. The segmented approach maintains relative assembly simplicity while improving manufacturing precision.

Inventive Principle:
Principle #1Segmentation

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 reduces the size and assembly complexity of the device while maintaining high detection accuracy and ensuring a good light emission state, preventing diffraction and intensity unevenness, thus enhancing the performance of image display systems.

Implementation Method 1

a collimator for collimating the light emitted from the light source

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

an optical element for making the light in a direction (a first direction) along the projection surface wide-angle out of the light collimated by the collimator

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

the projector detecting the position of the pointing body due to reflection of the light by the pointing body operated on the projection surface

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3511762B1Light emitting device and image display system
Publication Date: 2021.03.17 SEIKO EPSON CORP
  • EP3511762B1 patent drawingFigure 1
  • EP3511762B1 patent drawingFigure 2
  • EP3511762B1 patent drawingFigure 3

AI summary

A light emitting device (2) uses optical elements (33, 43) each formed of a plurality of small lenses (331, 431). On that basis, the array pitch of the plurality of small lenses is set within a predetermined numerical range determined based on a proportional relationship between two values with respect to the focal distance of a collimator (32, 42).