[It would definitely be an infringement if you call it the Lite Brite deck!
Ah yes, don't call it a light brite deck. However, you can call it a Bright Light deck with no worries, if you went with Brite Lite there could be some argument for infringement. As for the time to create every card on one of my 8 lite brites, I don't know if I have enough sanity left to handle it. However, I intend to forge on. The challenge is that pixellating an image to fit a standard 44 x 39 peg board is never going to work for face cards. The numbered cards are no issue at all. So I have to be creative while allowing for print at 2.5 x 3.5 without making it look like just a pixel image. I still think a 'Lite Brite' deck is a good idea.
Hasbro might still take a shot at it, claiming it's too similar to their product's name. If you called it something like "Color Dots" you'd have a better leg to stand on.
Just spoke to the really sweet people at Hasbro, they are quite friendly in customer service. The legal department, not so much. We had a 10 minute "we can take this in front of a judge" conversation, but admittedly they have no rights around the term Bright Lights, Bright Lights Big City and so on. I cannot show the product, product box... in any way. However the pegs being lit up they have no exclusivity to, they lost that years ago and the folks who create digital boards with LEDs already won the right to create pixelated art with light. I asked them if they wanted to hire me to design the deck on their behalf to help promote the product, they transferred me to R&D. The answer, "If we wanted to do it, we would do it in house." They apparently have Lite Brite expert level designers who can do this so much better than me. Oh well. Again, I put a lot of effort into something I'm not really sure I want to take on, but I so enjoy calling my friends over at Hasbro. Now I need to call PB to see if they want to join the 21st century and publish non-lame games.