I just saw this announcement in an A&E bulletin I received:
http://a-e-mag.com/news/universal-la...through-option
Seems ULS has obtained a patent (7723638) for some type of "conversion module" to allow a laser system to be converted from a Class I to Class IV laser system (Class I being enclosed and Class IV having a potentially exposed beam.)
I can't quite make out what the patent is actually claiming. Pass-through itself has been around a long time. It seems the gist of the patent is to make a "legitimate" Class I/Class IV laser system, whereas with my LaserPro, for example, I need to defeat the interlocks myself. (It is understood by GCC LaserPro that I need to do this, but the laser was not marketed as a Class IV unit.)
But to make a legitimate Class IV system the user needs to use safety glasses and I don't think any number of switches, sensors, or interlocks will detect that the user is wearing laser glasses. So I don't really understand what they have done that makes the system safer than what people are doing now. The main difference, I believe, is that they have "officially" made a CDRH compliant unit. In the past I think the manufacturers were reluctant to follow that route because it was easier to market a unit as a Class I than a Class IV. The user could use the system as a Class IV, but the manufacturer could potentially claim that it was sold as Class I.
I noticed this line from the patent itself - not sure if the wording was intentional or if the patent lawyer just has a sense of humor:
"Although many manufacturers of class I laser systems that include high-power lasers make reasonable efforts to prevent interlocks on the system's housing from being compromised and/or defeated, a significant number of conventional laser systems include safety features that are relatively easy to defeat and, furthermore, many manufacturers turn a blind eye to such issues."
The "conversion module" just seems to be a module that detects if doors or open and (perhaps) sets an indicator to say which mode you are in (Class I or Class IV). If you set the module to Class IV it probably just overrides the door switches allowing the laser to run. But the onus of course is still on the operator to wear the glasses.
I think it is good that ULS has "come clean" marketing the unit as a true Class I/Class IV but I am not so sure that it warranted a patent.