Method of manufacturing light beam scanning apparatus and fixed hologram plate and rotatable hologram and light distributing apparatus

A light-beam scanning apparatus comprising:

• an optical source producing a source optical beam;
• a scanning surface;
• a rotary hologram disk having a central axis and an outer circumference with the rotary hologram disk being rotatable about the central axis, the rotary hologram disk being positioned between said optical source and said scanning surface in the path of said source optical beam produced by said optical source,
• said rotary hologram disk being divided circumferentially around said central axis into a plurality of facets such that each facet occupies a portion of the outer circumference,
• the portion of the outer circumference occupied by each facet having a middle point that substantially equally divides the portion of the outer circumference,
• each facet at least partially containing an imaginary radial line extending from the central axis to the middle point of the portion of the outer circumference,
• each facet carrying a first diffraction grating pattern that produces a diffraction beam as a result of diffraction of said source optical beam,
• said first diffraction grating pattern including, in each facet, a plurality of straight lines extending parallel with each other in a direction generally perpendicular to the imaginary radial line of the facet,
• in each of said facets, said plurality of straight lines being disposed with a pitch that increases away from the central axis and toward the outer circumference such that the straight lines are further apart toward the outer circumference;
• a motor for rotating said rotary hologram disk about said central axis;
• and
• a fixed hologram disposed between said rotary hologram disk and said scanning surface in the path of said diffraction beam from said rotary hologram disk, said fixed hologram carrying a second diffraction grating pattern that produces a scanning optical beam as a result of diffraction of said diffraction beam, said scanning surface being scanned by said scanning optical beam.