Display Luminance Modulation for Visible Light Communication
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Solution Overview
Problem
Conventional methods for communication using visible light signals are limited to devices with three color light sources, restricting their application to lighting devices and not enabling communication with other types of devices.
Innovation Solution
A transmitting method that utilizes luminance changes in visible light signals, modulating the light signal pattern to switch on/off multiple light sources in a display, allowing for communication between various devices, including those without traditional lighting functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional visible light communication methods are used, then communication between lighting devices is enabled, but the method is limited to devices with three color light sources and cannot communicate with other device types
Solution Approach 1:
The patent applies universality by enabling display devices to perform both their primary display function and visible light communication function simultaneously. The display device can communicate with various types of devices (lighting, audio equipment, computing devices) using the same hardware infrastructure, eliminating the need for device-specific communication mechanisms and expanding compatibility beyond traditional lighting-only systems
2Adaptability or versatility
If multiple light sources are switched on/off for communication, then communication capability is enabled, but the display's primary image display function may be affected
Solution Approach 1:
The patent implements periodic action by modulating light sources in a time-division manner, where communication signals are transmitted during specific time intervals when certain light sources are activated while others remain inactive. This periodic switching allows the display to maintain its image display function during non-communication periods while enabling communication during designated time slots, thus preserving both functions without mutual interference
Solution Approach 2:
The patent applies segmentation by dividing the light source group into multiple independent controllable light sources, each capable of being selectively activated. This segmentation allows the system to activate only the necessary light sources for communication while keeping others inactive for display purposes, enabling simultaneous operation of both communication and display functions without compromising either
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 effective communication between diverse devices beyond just lighting systems by using luminance changes in visible light signals, facilitating data transmission without altering the display's primary functionality.
Implementation Method 1
transmitting a visible light signal by way of luminance change
Data Source
AI summary
A visible light signal transmitting method includes: determining a luminance change pattern to transmit the visible light signal; switching a common switch according to the luminance change pattern, the common switch being for turning ON a plurality of light sources in common; and turning ON a first pixel switch, to cause the first light source to be ON for a period in which the common switch is ON and the first pixel switch is ON, to transmit the visible light signal, the first light source being one of the plurality of light sources. In the turning ON of a first pixel switch, when the image is displayed on the display, the first pixel switch is switched to increase a lighting period that corresponds to the first light source, to compensate a period in which the first light source is OFF for transmission of the visible light signal.