Interactive, computer based orthodontist treatment planning, appliance design and appliance manufacturing is described. Use of the present invention enables screening for a chemical which regulates excretion of a chemical andor a waste. 3 or higher when the electrophotographic photoreceptor is charged to a charged potential absolute value of 500 V and then irradiated with a monochromatic light of the same wavelength as that of the light beams to decay the charged potential absolute value to 250 V. The single marker will also disclose the orientation as well as the location of the seed. Examples of such securities include stocks, a mutual funds, and options. The projector includes: a light source device; an electro-optic device that modulates light emitted from the light source device; two polarizers that are disposed respectively on a light incoming side and a light outgoing side of the electro-optic device; and a projection optical system that projects light output from the electro-optic device.