have you looked at replacing the polarizing filter that is attached to the front of the LCD? i can't guarantee this will fix it, but worth a try.
a very good source of polarizing film is from the front of a discarded or broken colour LCD monitor. this requires extracting the panel from the monitor, then very carefully stripping out the front polarizing film using whatever solvents you have to hand to dissolve the adhesive. i did a 22" monitor recently, and after a couple of hours ended up with a 19" x 10" sheet - enough to last a lifetime! btw, i found the rear film was too thin to extract.
thankfully, removing the polarizing filter from the front of a small LCD like used in the fluke 77 meter is far easier, it can generally just be peeled off with due care and patience. once you have it removed, you can check if a replacement will help by viewing through a scrap of polarizing film held by hand.
cheers,
rob :-)