What is claimed the ornamental design for a light barrier for gates, as shown and described.
FIG. 1 is a front perspective view of a light barrier for gates, showing my new design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a front elevation view thereof;
FIG. 4 is a rear elevation view thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is a bottom plan view thereof;
FIG. 7 is left elevation view thereof; and,
FIG. 8 is a right elevation view thereof.
The phantom lines showing indicia on the front of the light barrier for gates along with raised elements and a concavity on the rear of the light barrier for gates are included for the purpose of illustrating portions of the light barrier for gates and form no part of the claimed design.