Measuring Light Therapy Device's Power

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There are many factors to consider when looking for the best light therapy device: design quality, setup options, warranty & service, safety certifications, and power output. A red light therapy device’s power and energy tend to be the most confusing and misleading factors. We explain how to determine the light therapy device’s power in this article.

The Basics of Measuring Light Therapy Power

At Kaiyan, we have two ways to evaluate light power from a light therapy device.

1. Radiant Flux or Total Light Output: This measures the maximum light-emitting capability or how it converts electrical power into light energy. This is the most accurate way to measure a lightweight therapy device by evaluating its spectral power distribution (SPD). This measurement requires an integrated sphere measuring device. The standard unit for radiant flux is milliwatts (mW) or watts (W).

2. Irradiance: Provides a measurement of power at a specific distance from the light source over a specified area. This is the power value used to determine the energy delivered during treatment. The standard unit for irradiance is mW/cm2, which provides milliwatts over a square centimeter.

The trend of promoting red light therapy devices to market their irradiance has become more common, even though it can be misleading. The companies want you to believe that more power is always better and offers the most. They use solar meters to measure their devices, which are intended for solar panels, not light therapy products. This is very misleading and has created confusion for buyers.

Power meters have to be calibrated to the wavelength of light they are measuring and can only measure one wavelength at a time. This means you cannot measure red light at ~660 nm simultaneously with infrared light at ~850 nm. Some companies do this, and they pass on meaningless specs to their customers.