Lens evaluation method, lens evaluation device, lens manufacturing method, and lens characteristic display method

A lens evaluation device comprising:

• a power distribution measuring device for measuring power which includes spherical power, cylindrical power and cylinder axis at a plurality of measurement points of a spectacle lens to obtain an actually measured power distribution;
• and an evaluation computer having a processor for evaluating the spectacle lens using the actually measured power distribution, wherein the processor of the evaluation computer performs:
• a power distribution converting process obtaining a power distribution of the plurality of measurement points in an arbitrary direction based on the actually measured power distribution;
• a calculation power distribution creating process for creating a calculation power distribution of the spectacle lens;
• a difference distribution calculating process for obtaining a difference distribution between the actually measured power distribution, which indicates an actual power distribution of the spectacle lens, and the calculation power distribution;
• a difference index calculating process for obtaining a difference index by differentiating the difference distribution obtained in the difference distribution calculating process with respect to the distance between the plurality of measurement points in the lens;
• and an evaluation process for evaluating the spectacle lens based on the difference index calculated in the difference index calculating process.

A method for manufacturing a spectacle lens comprising:

• a step for optically finishing optically-unfinished surface(s) of a lens blank;
• and
• a lens evaluation step for evaluating whether a difference from design data of the lens with both surfaces optically finished is within an allowance or not,
• wherein the lens evaluation step includes:
• a power distribution converting step for obtaining a power distribution of a plurality of measurement points in an arbitrary direction based on an actually measured power distribution of the spectacle lens, the actually measured power distribution consisting of a point group indicating spherical power, cylindrical power and cylinder axis;
• a calculation power distribution creating step for creating a calculation power distribution of the spectacle lens;
• a difference distribution calculating step for obtaining a difference distribution between the actually measured power distribution, which indicates an actual power distribution of the spectacle lens, and the calculation power distribution;
• a difference index calculating step for obtaining a difference index by differentiating the difference distribution obtained in the difference distribution calculating step with respect to distance between the plurality of measurement points in the lens;
• and
• an evaluation step for evaluating the spectacle lens based on the difference index calculated in the difference index calculating step.

A method for displaying characteristics of a lens comprising:

• a power distribution converting step for obtaining a power distribution of a plurality of measurement points in an arbitrary direction based on an actually measured power distribution of a spectacle lens, the actually measured power distribution consisting of a point group indicating spherical power, cylindrical power and cylinder axis;
• a calculation power distribution creating step for creating a calculation power distribution of the spectacle lens;
• a difference distribution calculating step for obtaining a difference distribution which represents a distribution of a difference between the actually measured power distribution, which indicates an actual power distribution of the spectacle lens, and the calculation power distribution;
• a difference index calculating step for obtaining a difference index by differentiating the difference distribution obtained in the difference distribution calculating step with respect to distance between the plurality of measurement points in the lens;
• a difference index distribution creating step for creating, based on the difference index calculated in the difference index calculating step, a distribution of the difference index within the spectacle lens;
• and a display step for displaying the difference index distribution created in the difference index distribution creating step.