I just bought a Fenix HT30R LEP light. Although the beam is much more directional than a traditional flashlight, it does diverge more than I was expecting for a ’laser-like’ light source. In addition, the beam intensity distribution is not very uniform: it has very bright center (~50% of full beam width) and a much less intense outer radius.
Upon closer inspection, the emitter surface appeared fuzzy when viewed through the lens. It looks to me that the lens back surface has a patterned droplet surface (as shown in the close-up photo), which, I suppose, creates a minor diffusion effect. In the review videos of other LEP sources, the lenses have always looked fully transparent such that you can see the emitter very clearly.
I am trying to understand the design choice: is this to minimize backreflections & optical feedback to the laser emitter, or are there other possible explanations? I know diffuser lenses are sometimes used in led-based illumination to hide the emitter self image, but that should not be an issue in an LEP-based illumination. Could it be related to safety regulations? This Fenix LEP is a Canadian edition classified as a Class 1 laser. I read that Canada considers LEPs as laser lights, which subjects them to more scrutiny.
On a sidenote, has anyone taken apart the lens housing of the HT30R. I would like to inspect the emitter more closely. I am aware that this will void the warranty and cause the beam tp diverge a lot.
by kakkapaska111
