Projector Visible Light Communication via Luminance Modulation

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Solution Overview

Problem

Conventional methods for communication between devices are limited to devices with three color light sources and are not effective for devices with low computational performance or those that do not have a communication function due to cost constraints.

Innovation Solution

An information communication method that uses a change in luminance to transmit signals, where multiple patterns of luminance change are determined by modulating signals, and each light emitter changes luminance according to a specific pattern, with different light emitters changing at different frequencies to output light of varying luminance types over predetermined time units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional communication methods using three color light sources are used, then communication function is achieved, but device complexity and cost increase

Engineering Contradiction:

Improvecommunication functionVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the communication function from complex multi-color light source systems and implements it using simple single-color light sources. By using only one color of light and encoding information through temporal patterns of illumination, the system achieves communication capability without requiring multiple color light sources, thereby reducing device complexity and cost.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs periodic action by using time-varying illumination patterns where light sources are turned on and off in specific sequences. This temporal modulation allows information to be encoded and transmitted through simple light sources without requiring complex spectral capabilities, enabling communication while minimizing device complexity.

Inventive Principle:

Principle #19Periodic action

2Loss of information

If multiple color light sources are used for communication, then information transmission capability is improved, but computational performance requirements increase

Engineering Contradiction:

Improveinformation transmission capabilityVSAvoidcomputational performance

Core Design Contradiction:

Loss of informationVSPower

Solution Approach 1:

The patent uses simple, low-cost single-color light sources that can be easily controlled by basic microcontrollers rather than requiring expensive, computationally intensive multi-color lighting systems. The communication is achieved through straightforward temporal patterning that can be implemented with minimal computational resources, making the system suitable for devices with low computational performance.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Device complexity

If simple single color light sources are used, then device complexity is reduced, but communication capability is limited

Engineering Contradiction:

Improvedevice complexityVSAvoidcommunication capability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamics by using time-varying illumination patterns where the temporal structure of light emission carries information. By dynamically controlling when light sources are active rather than relying on static color differentiation, the system achieves communication capability with simple single-color light sources, maintaining low device complexity while enabling versatile information transmission.

Inventive Principle:

Principle #15Dynamics

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 communication between various devices, including those with low computational performance, by effectively utilizing changes in luminance to transmit signals, thereby overcoming the limitations of existing methods.

Implementation Method 1

transmitting a signal using a change in luminance, the information communication method including: determining a plurality of patterns of the change in luminance, by modulating a respective plurality of signals to be transmitted

Methodology Applied

Scientific EffectOptical modulation: Phase Modulation

Data Source

PatentUS20250030949A1Information communication method

Publication Date: 2025.01.23 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA

AI summary

A visible light communication method transmits a signal by visible light communication. The visible light communication method includes modulating the signal into a predetermined blinking pattern, and transmitting the signal by causing visible light to blink according to the predetermined blinking pattern and toward a wall, from a projector disposed in an indoor space surrounded by the wall. The visible light communication method also includes projecting video from the projector toward the wall, wherein the visible light is reflected by the wall to prevent the signal from being received outside of the indoor space, and the signal is used to transmit data related to the video projected to a terminal in the indoor space.