Gradient-Index Optical Element for Omnidirectional Light Collection

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Solution Overview

Problem

Conventional optical elements, such as wide-angle lenses, face difficulties in collecting light from a 360° viewing angle, or omnidirectionally, leading to inefficiencies in light collection and utilization.

Innovation Solution

A spherical optical element with a continuous gradient index distribution, where the refractive index attenuates radially from the center, allowing omnidirectional light collection and absorption, preventing light loss through gradual index changes and incorporating an area with a non-zero imaginary refractive index for efficient energy conversion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional wide-angle lens is used, then light can be collected from a wide viewing angle, but it is difficult to collect light from a 360° omnidirectional viewing angle

Engineering Contradiction:
Improveviewing angle rangeVSAvoidlight collection efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent applies parameter changes by implementing a continuous gradient in the refractive index from the center to the periphery of the optical element. This gradient index distribution (where the refractive index varies continuously according to the radial distance from the center) enables light rays from all directions (360° viewing angle) to be refracted and focused onto the photovoltaic cell, achieving both omnidirectional adaptability and high light collection efficiency that conventional lenses cannot achieve

Inventive Principle:
Principle #35Parameter changes

2Productivity

If light is collected from all directions, then light utilization efficiency is enhanced, but light loss occurs in conventional optical elements

Engineering Contradiction:
Improvelight utilization efficiencyVSAvoidlight loss
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The continuous gradient in refractive index parameter ensures that light rays from any incident angle are progressively bent toward the optical axis and focused onto the photovoltaic cell without abrupt refraction at interfaces. This gradual parameter change eliminates sudden directional changes that cause reflection losses, thereby achieving high light utilization efficiency while minimizing energy loss

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts what would normally be harmful effects (light reflection and scattering at interfaces) into beneficial focusing action through the gradient index distribution. The varying refractive index creates continuous refraction that redirects potentially lost light rays onto the photovoltaic cell, turning interface reflection losses into useful light concentration

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

Enables the omnidirectional collection and absorption of light, enhancing light utilization efficiency and allowing for applications like high-efficiency lighting apparatuses and solar cell devices that can capture light from all directions without the need for directional tracking.

Implementation Method 1

a continuous gradient index distribution area which is configured to continuously attenuate a refractive index from a center of the optical element in a radial direction

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

The first medium includes an area where absolute value of imaginary part of a complex refractive index is greater than zero

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentEP3795923B1Optical element, lighting apparatus, and solar cell device
Publication Date: 2024.11.06 KK TOSHIBA
  • EP3795923B1 patent drawingFigure 1~2
  • EP3795923B1 patent drawingFigure 3~4
  • EP3795923B1 patent drawingFigure 5~6

AI summary

According to one embodiment, an optical element includes a continuous gradient index distribution area, and a first medium. The continuous gradient index distribution area is configured to continuously attenuate gradient index from a center of the optical element in a radial direction. The first medium is at the center. The first medium includes an area where absolute value of imaginary part of a complex refractive index is greater than zero.