| 摘要 |
PURPOSE:To obtain high image formation performance by making the refractive surface of a single acrylic resin-made finite magnification lens having a prescribed optical constant an aspheric surface having a prescribed shape. CONSTITUTION:Table 1 shows the number NA' of apertures of a finite group of a finite magnification lens, the number NA of apertures of an infinite group, a focal length EFL, i.e. a length from a main plane to the focus, a back focal length BFL, i.e. a length from a refractive surface on the optical recording medium side to a focus on the optical recording medium side, a front focal length FFL, i.e. a length from a refractive surface on the light source side to a focus on the light source side, the magnification beta of image formation, the thickness (d) of the center, an incident pupil diameter EPD, a working distance WD, and a distance l between the light source and an optical glass 12. In addition, Table 2 shows factors Cv1, K1, A1-D1 indicating the refractive surface of the finite magnification lens 14 on the light source side and factors Cv2, K2, A2-D2 indicating the refractive surface on the optical recording medium side. |
