A device for measuring the working distance of a corneal topograph

Abstract

The invention discloses a working distance measuring device and measuring method of a corneal topography instrument, which is characterized in that it includes a corneal photographing component and a distance measuring optical path component. Two lenses and the first photodetector, the distance measuring optical path assembly includes a beam splitting unit, a transmitting and receiving unit and a drive motor, the beam splitting unit is arranged on the optical axis of the cornea photographing assembly, and the beam splitting unit is located between the first lens and the second lens Between, for the light transmitted into the cornea photographing assembly and the light reflected into the transmitting and receiving unit, the driving motor is used to drive the transmitting and receiving unit to move back and forth along the direction perpendicular to the optical axis of the corneal photographing assembly; the advantage is that through this The measuring device and method can accurately measure the working distance of the corneal topographer when photographing the cornea, so that the restoration accuracy of the corneal curvature is higher, thereby making the diagnosis of corneal diseases more accurate by the corneal topographer.

Description

technical field [0001] The invention relates to a corneal topography instrument for inspecting the cornea, in particular to a measuring device for the working distance of the corneal topography instrument. Background technique [0002] The corneal topography instrument based on the Placido (Placido's) disc has diopter visualization, can draw various topographic maps of the cornea more accurately, can diagnose a variety of corneal diseases, and guide various corneal operations effectively. It has many advantages such as diverse measurement data and strong analysis ability, and it is very popular in the medical market. [0003] In general corneal topographs, in order to clearly capture the apex of the cornea and the surrounding cornea, and to keep the magnification β constant, an object space telecentric lens is often used, which is characterized by a larger object space Depth of field, so when collecting images, clear images can also be captured under different working dista...

AI Technical Summary

Problems solved by technology

[0003] In general corneal topographs, in order to clearly capture the apex of the cornea and the surrounding cornea, and to keep the magnification β constant, an object space telecentric lens is often used, which is characterized by a larger object space Depth of field, so when collecting images, clear images can also be captured under different working distances (that is, the distance from the corneal apex to the first lens), but it brings great uncertainty to the restoration of the final corneal curvature radius Therefore, in order to improve the restoration accuracy of the corneal curvature, it is necessary to determine a more accurate value of the working distance

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