Patent ID: 7609371

Claim:
A lens meter for measuring optical characteristics of a lens to be measured, comprising: a measurement optical system including a light source which projects a measurement light beam to the lens, a target plate having a number of measurement targets, and a light receiving sensor which detects images of the targets formed by the measurement light beam having passed through the lens and the target plate; an arithmetic part which obtains optical characteristic distribution of a predetermined measurement region of the lens based on a detection signal of the light receiving sensor; a display; a control part that controls the display; and a mode switching means that switches a measurement mode to a measurement mode for a progressive multifocal lens having a near vision portion and a progressive portion, the progressive multifocal lens measurement mode including graphically displaying the near vision portion and the progressive portion and the measurement region on the display so that the near vision portion is brought into the measurement region; the arithmetic part being adapted to determine whether or not the near vision portion is in the measurement region based on whether or not a distribution of spherical power or a distribution of additional power in a vertical direction in the measurement region and a distribution of distortion amount in a lateral direction in the measurement region satisfy respective predetermined conditions, and determine whether or not a spectacle frame or an edge of the lens is detected based on the detection signal of the light receiving sensor without satisfying a determination condition for the near vision part.