Define Principal ray. Principal ray synonyms, Principal ray pronunciation, Principal ray translation, English dictionary definition of Principal ray. the line drawn through the point of sight perpendicular to the perspective plane. See also: Principal We
wherein both the entrance surface and the exit surface of all of the at least one imaging optical element constituting the second optical system through which the incident beam passes are concave toward the deflecting device in the sub-scanning section, and wherein all of the at least one imag...
(4) one of the principal rays of the incident beam and the principal ray of the scanning beam travels on one of the upper and lower side of the optical axis L of the first and second scanning lenses 61 and 62, and the other travels on the other side in the sub-scanning section, in...