About This Blog
Engineering Notes explores the measurement science, photobiomodulation research, and engineering decisions that influenced the development of Rejuvulite. Technical articles are written for a general audience and focus on dose, irradiance, calibration, and light delivery.
Written for a general audience; published in Innovating Resourcefully on Medium
Selected articles on dose, irradiance, calibration, and light delivery.
Photobiomodulation research is conducted in dose. Consumer devices are operated by time. Open almost any PBM paper and you’ll find a carefully reported protocol: wavelength, irradiance, treatment frequency, and delivered dose in J/cm². Dose is the controlled variable. It’s what researchers [...]
Three things have come together this month that, taken individually, are each meaningful progress. Together, they represent a hardware and software stack that does what it was designed to do: deliver a known, reproducible dose of light — measured in joules, [...]
Rev 2 hardware is in fabrication. Here’s where things stand. Background The Rejuv is a handheld red and near-infrared light therapy device designed around a specific principle: that delivered dose — measured in J/cm² at the treatment surface — should be [...]
1. Why measurement matters When evaluating a photonic device, the quantity of interest is the optical power delivered per unit area. As the LEDs are spread out, so too is the energy. Because the LEDs are distributed across a surface, the [...]
A common criticism of compact, battery-powered devices is that they do not deliver sufficient total optical power (“watt”), particularly when compared to large, AC-powered panels. What determines local irradiance, however, is power density (mW/cm²) rather than total emitted power. For a [...]
This post documents the optical and thermal behavior of the current generation device. Older blog posts document earlier design iterations and are retained for historical context. Purpose This post summarizes optical output and thermal behavior measurements for the current generation of [...]
Simple Devices aren’t Simple At first glance, a handheld light-emitting device appears straightforward: an array of LEDs, a battery, and a housing. In practice, aligning such a device with the optical power densities commonly referenced in published light therapy research presents [...]
