VIEWER WITH MULTIFOCAL LENS AND METHOD FOR CHANGING FOCAL LENGTH OF VIEWER

摘要

A viewer includes a multifocal lens capable of setting one of a plurality of focal lengths. When a measuring section detects a change in gazing point distance, a selection section selects a focal length to be set among the plurality of focal lengths, and a determiner determines a time duration before a focal length of the multifocal lens is changed. A controller changes the focal length of the multifocal lens when a detector detects a blink or saccadic eye movement of the user before the determined time duration elapses.

主权项

1. A viewer comprising:
a multifocal lens capable of setting a focal length among a plurality of predetermined focal lengths; a controller that controls the focal length of the multifocal lens; a measuring section that measures a gazing point distance of a user and detects a change in the gazing point distance; a selection section that selects a focal length to be set among the plurality of focal lengths based on the measured gazing point distance when the measuring section detects a change in the gazing point distance; a determiner that determines a time duration from detection of a change in the gazing point distance to a change in the focal length of the multifocal lens in a case where the focal length selected by the selection section is different from a current focal length; and a detector that detects a blink or saccadic eye movement of the user, wherein in switching the focal length of the multifocal lens from the current focal length to the focal length selected by the selection section, the controller changes the focal length of the multifocal lens upon detection of a blink or saccadic eye movement by the detector during the time duration determined by the determiner from the detection of the change in the gazing point distance.