LED lights work by targeting the bacteria (P. Acnes) that causes acne. Various LED colors provide different benefits. Several light sources combine both blue and red. They are more effective than using just the blue LED alone. LED treatments are painless treatments and can be used for all skin colors. Comedones and severe acne will not usually respond well. Scarring does not improve. A laser such as the smooth beam is an effective procedure for both severe acne and acne scarring.
There would be no effect on the depth of acne scars. The best improvement would be from a lessening of redness if you acne scars are still retaining color.

To date, Fraxel Retore and similar fractional lasers which are used multiple times are the best way to lessen acne scars. The skin responds to laser by producing new collagen. With multiple laser procedures, you have the advantage of multiple incidences of new collagen stimulation and this is what lessens the depth of scars.