Horizontal Scanlines

1. Create a 1 X 3 Document make sure its transparent

2. Zoom in and put a black dot in the middle

Like so:



3. Edit>Define Pattern

Diagonal Scanlines

1. Create a 3 X 3/2 x 2 document make sures it transparent

2. Zoom in and put a diagonal lines from corner to corner

Likes so:



3. Edit>Define Pattern