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 given power density, total required power scales directly with emitting area: larger panels necessarily […]
Monthly Archives: January 2026
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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 the Rejuvulite handheld red / near-infrared device. It is intended to provide transparency into […]
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 a set of nontrivial engineering constraints. To illustrate why, consider irradiance on the order […]