Pentax 6X7 AL lenses

Can anyone tell me what the AL stands for in the Pentax 67 lens line?

Larry

"The Pentax 75mm f/2.8 AL (Aspheric Lens) is moderately wide angle lens that is an interesting alternative to the 90mm standard lens.

Pentax lenses have been developed using the latest in computer-assisted optical design technology. Lens surfaces are treated with Pentax's exclusive Super-Multi-Coating for sharp, high-contrast images "