Ball Lens Light Receiver for Wavelength-Multiplexed Spatial Optical Signals

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Solution Overview

Problem

Existing spatial optical communication systems struggle to receive wavelength-multiplexed spatial optical signals with sufficient intensity due to the deviation of signal light irradiation positions across different wavelengths.

Innovation Solution

A light receiver configuration that includes a ball lens, an irradiation position detector, a wavelength separator, and a light receiving element group. The irradiation position detector detects the irradiation position of the signal light, and the wavelength separator separates the signal light into different wavelengths, allowing each wavelength to be received by dedicated communication light receiving elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple photodiodes are arranged side by side in the condensing range to receive wavelength-multiplexed spatial optical signals, then the wavelength separation capability is improved, but the light receiving area for each wavelength decreases

Engineering Contradiction:

Improvewavelength separation capabilityVSAvoidlight receiving area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent transitions from a two-dimensional planar arrangement of photodiodes to utilizing the three-dimensional spherical surface of a ball lens. By positioning photodiodes on the spherical surface at different angular positions, the system achieves wavelength separation through angular differentiation rather than spatial adjacency, thereby maintaining adequate light receiving area for each photodiode while enabling multi-wavelength reception.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent divides the wavelength separation function into multiple independent photodiodes positioned at different angular positions on the spherical surface. Each photodiode is dedicated to receiving a specific wavelength range, and the ball lens segments the incoming wavelength-multiplexed light into different angular directions corresponding to different wavelengths, allowing each photodiode to operate with sufficient light collecting area.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If photodiodes are arranged side by side to separate wavelengths, then the wavelength diversity is improved, but the light receiving intensity decreases

Engineering Contradiction:

Improvewavelength diversityVSAvoidlight receiving intensity

Core Design Contradiction:

Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The patent utilizes the spherical geometry of the ball lens to distribute wavelength-separated light in different angular directions. Photodiodes positioned at different angular positions on the spherical surface receive light from their respective wavelength ranges with concentrated intensity, rather than sharing a common planar detection area where intensity would be diluted across multiple adjacent elements.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If a liquid crystal device is used to selectively receive light beams, then the beam selection capability is improved, but the irradiation position deviation correction is not achieved

Engineering Contradiction:

Improvebeam selection capabilityVSAvoidirradiation position accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces the liquid crystal-based electronic beam switching mechanism with an optical solution using a ball lens. The ball lens passively separates wavelength-multiplexed light into different angular directions through refraction, eliminating the need for active beam switching and automatically correcting irradiation position deviations by directing each wavelength to its appropriate detection position based on its angle of incidence.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enables the light receiver to effectively receive wavelength-multiplexed spatial optical signals with sufficient intensity by accurately detecting and separating the signal light across different wavelengths.

Implementation Method 1

a ball lens 11... a signal light derived from the spatial optical signal condensed by the ball lens 11

Methodology Applied

Scientific EffectLens focusing: Lens

Implementation Method 2

a wavelength separator 13 that wavelength-separates a signal light having a plurality of wavelengths

Methodology Applied

Scientific EffectWavelength separation: Prism

Data Source

PatentUS20250076595A1Light receiver, communication device, and communication system

Publication Date: 2025.03.06 NEC CORP

AI summary

Provided is a light receiver that includes a ball lens, an irradiation position detector that detects an irradiation position of a signal light condensed by the ball lens, a wavelength separator that wavelength-separates a signal light having a plurality of wavelengths used for spatial optical communication from a signal light condensed by the ball lens, and a light receiving element group including a plurality of communication light receiving elements that receive a signal light having the plurality of wavelengths wavelength-separated by the wavelength separator.