Patent ID: 7474466

Claim:
A stereoimage display apparatus comprising: an erecting-unmagnifying lens module including a plurality of microlenses, arranged uniformly with a fixed pitch, and having a focusing distance; and a display device including an image display screen, separated from the erecting-unmagnifying lens module by the focusing distance, and a plurality of pixels, arranged uniformly with a fixed pitch, wherein the image display screen displays an image, wherein: the erecting-unmagnifying lens module uses the image displayed on the image display screen to form a stereoimage that appears as a floating image due to binocular disparity; distance between the erecting-unmagnifying lens module and the image display screen is changeable within a predetermined range; resolution of the erecting-unmagnifying lens module changes when the distance is changed within the predetermined range; and the resolution of the erecting-unmagnifying lens module is greater than a maximum value at which a blurriness is noticeable with human eyes when the distance between the erecting-unmagnifying lens module and the image display screen is in the predetermined range; wherein the erecting-unmagnifying lens module includes: at least two lens array plates, each lens array plate including a plurality of microlenses, each having an optical axis and a peak, wherein: the optical axes of the microlenses are parallel to one another; the optical axes of the microlenses in one of the at least two lens array plates are aligned with the optical axes of the microlenses in the other one of the at least two lens array plates; the peaks of the microlenses in one of the at least two lens array plates are in contact with or located proximal to the peaks of the microlenses in the other one of the at least two lens array plates; and the microlenses of each lens array plate each have a predetermined spherical aberration greater than a minimum spherical aberration; wherein if PD represents the pixel pitch of the plurality of pixels, PL represents the lens pitch of the microlenses arranged uniformly with a fixed pitch, LA represents the distance between a viewpoint and the image display screen, LB represents the distance between the stereoimage and the viewpoint, Lz represents the distance between the erecting-unmagnifying lens module and the image display screen, and PLo represents the correction lens pitch obtained by correcting the lens pitch PL in accordance with the distances LA, LB, and Lz, and when the distance Lz is minimal, the correction lens pitch PLo satisfies the expression of: (1.20 +n* 1.50)≦ PLo/PD ≦(1.70 +n* 1.50), where n=0, 1, 2, 3, . . . .