Two-Way Optical Communication Using Time-Division Multiplexing
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Solution Overview
Problem
Existing two-way optical communication systems using shared light pipes face challenges in maintaining high optical bit rates while providing constant illumination or visibly perceptible device states, as they are limited by interference and require significant time or low data rates, especially when using inexpensive optical sensors that sense over a broad spectrum.
Innovation Solution
A system comprising a transmit element, a receive element, and a transceive processor that controls the light pipe to pause and resume transmitting optical signals during intervals, allowing for simultaneous reception of optical data, with the processor managing duty cycles to maintain a constant illumination perception by the human eye and enable high bit rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If transmit circuits and receive circuits share a single light pipe, then device size and weight are reduced, but transmit circuits interfere with receive circuits
Solution Approach 1:
The patent implements time-division multiplexing where the light pipe alternates between transmit and receive modes in periodic intervals. The controller activates the transmit circuit during transmit intervals and the receive circuit during receive intervals, preventing simultaneous operation and thus eliminating interference while maintaining shared light pipe architecture
Solution Approach 2:
The system dynamically switches the operational state of the light pipe between transmission and reception based on timing signals from the controller. This dynamic allocation allows the same physical resource to serve dual functions without conflict, adapting its purpose in real-time according to the communication protocol
2Measurement precision
If transmit circuits pause transmission during receive intervals, then receive sensitivity is improved, but optical bit rate is reduced
Solution Approach 1:
The controller implements periodic transmit and receive intervals with precise timing control. During receive intervals, the transmit circuit is deactivated to maximize receive sensitivity, while during transmit intervals, data is sent at high speed. The cumulative effect over multiple periods maintains the overall optical bit rate while ensuring adequate receive sensitivity during each receive window
3Object-affected harmful factors
If opaque materials are placed in interference paths, then receive circuit interference is reduced, but light transmission efficiency is reduced
Solution Approach 1:
Instead of using opaque materials to block light paths, the system uses temporal separation where the light pipe is dedicated to transmission during transmit intervals and to reception during receive intervals. This eliminates the need for physical blocking materials that would attenuate light, maintaining full transmission efficiency while preventing interference through time-division isolation
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 reliable two-way optical communication with constant illumination or visibly perceptible device states, supporting higher optical bit rates than previous systems, while minimizing interference and allowing for efficient data reception through the shared light pipe.
Implementation Method 1
light pipes are generally manufactured from plastic materials that transport light via a reflective lining, or transparent solids that transport the light by total internal reflection
Implementation Method 2
one or more light emitting diodes (LEDs) disposed therein to indicate status
Implementation Method 3
transmit element coupled to a light pipe and configured to transmit a first optical signal through the light pipe
Implementation Method 4
receive element coupled to the light pipe and configured to receive a second optical signal through the light pipe
Data Source
AI summary
An two-way optical communication apparatus, including a transmit element, a receive element, and a transceive processor. The transmit element is coupled to a light pipe, and transmits a first signal. The receive element is coupled to the light pipe, and receives a second signal. The transceive processor directs the transmit element to pause and then resume transmitting the first signal during first intervals, and directs the receive element to sample for the second signal during one or more second intervals within each of the first intervals, where the each of the first intervals is less than a first value and the first intervals occur at a duty cycle no greater than a second value, and where the first and second values are controlled by the transceive processor such that a user perceives the first optical signal as having a constant state for a third interval.