Optical apparatus and instruments, namely, optical filters; electronic components, namely, programmed data-carrying electronic circuits, electronic timing and synchronizing circuits, electronic filters used for electronic circuits, piezoelectric filters, resonators, resonators adapted for use in computers, crystal resonators, piezoelectric resonators, electronic resonators used for electronic circuits, oscillators, oscillators adapted for use in computers, crystal oscillators, piezoelectric oscillators, electronic oscillators used for electronic circuits, crystal filters, optical low pass filters for use in video cameras, digital still cameras, security cameras and digital single-lens reflex cameras, optical filters; optical thin films used as color compensation filters for various pickup devices; crystal plates for projectors; crystal phase plates for projectors; wave plates, namely, wave plates for use in separating the polarizing properties of light and depolarizers which transform the rays that become polarized after passing through the double refraction plate into non-polarized rays; polarizers, namely, optical plates which convert natural light into polarization; hybrid integrated circuits