Backlight Control Signal Superimposition for Visible Light Communication

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Solution Overview

Problem

Existing display devices face challenges in outputting visible light communication signals without deteriorating the quality of the display image and reducing receiving errors, particularly due to the need to avoid superimposing signals during backlight OFF periods in backlight scanning methods.

Innovation Solution

A display device configuration that includes a display panel, a display controller, a backlight with a light emission surface, a signal processor, and a backlight controller, which superimposes visible light communication signals on backlight control signals by avoiding periods indicating an OFF state of the backlight, allowing for synchronized light emission control across regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If visible light communication signals are superimposed on backlight control signals during normal video display, then communication functionality is achieved, but display image quality deteriorates and receiving errors increase

Engineering Contradiction:

Improvecommunication functionalityVSAvoiddisplay image quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The backlight control signal period is divided into multiple time regions (first time region for image display, second time region for communication). By segmenting the time domain, the patent enables simultaneous achievement of high-quality display and reliable communication without mutual interference.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The backlight controller performs periodic switching between image display mode and communication mode. During the first time region, backlight control signals drive image display; during the second time region, visible light communication signals are output. This periodic alternation ensures both functions operate at optimal performance levels.

Inventive Principle:

Principle #19Periodic action

2Adaptability or versatility

If visible light communication signals are superimposed on backlight control signals, then communication is enabled, but receiving error rate increases

Engineering Contradiction:

Improvecommunication capabilityVSAvoidsignal reception accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the signal transmission timeline into distinct phases: image display phase where backlight control signals operate independently, and communication phase where visible light communication signals are transmitted. This temporal segmentation prevents signal interference and reduces receiving errors.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The backlight controller acts as an intermediary that coordinates between image display requirements and communication signal transmission. It manages the timing and switching between different signal types, ensuring clean transitions and preventing overlapping that would cause receiving errors.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If backlight scanning is used for visible light communication, then communication signals can be output, but display image quality significantly deteriorates

Engineering Contradiction:

Improvevisible light communication outputVSAvoiddisplay image quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

Instead of continuous backlight scanning that degrades image quality, the patent uses periodic action by confining communication signal output to specific time windows (second time region) when image display is not active. This periodic switching maintains image quality while enabling communication functionality.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent segments the backlight operation into display-oriented time regions and communication-oriented time regions. By separating these functions temporally rather than spatially (as in traditional scanning), the system achieves communication capability without compromising display image quality.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS10068532B2Display device including signal processor that superimposes visible light communication signals on backlight control signals generated based on an image signal

Publication Date: 2018.09.04 PANASONIC HOLDINGS CORP

AI summary

A display device includes: a display panel including a display screen; a backlight having a light emission surface that illuminates the display screen of the display panel from behind; a second processor that superimposes the visible light communication signals on backlight control signals generated based on the image signal; and a second controller that divides the light emission surface of the backlight into regions and establishes a period during which control of light emission in each of the regions and control for turning off the backlight in each of the regions a different time are performed based on the backlight control signals outputted by the second processor. When superimposing the visible light communication signals on the backlight control signals, the second processor does not superimpose a visible light communication signal in a period indicating an OFF state of the backlight in the backlight control signals.