"invisible light" is an oxymoron, unless they are talking about IR or UV. They also call it "bright" in the same paragraph. If it appears bright to the operator of the beam, it cannot be invisible light.
I'm suggesting that the USPTO people can't spot glaring errors of logic in a simple introductory paragraph of text that is devoid of complicated technical or legal language.
No wonder they grant applications for obvious programming techniques, like oh ... the use of XOR to draw a sprite on a black-and-white pixel display, such that if it is drawn again at the same location, it is erased, restoring the original background.
I had to re-read that part. They are talking about an ordinary red or green laser pointer. The beam itself is hardly visible compared to the spot on the wall--unless your air contains a lot of dust or smoke or fog.