Positioning mechanism of ophthalmologic apparatus

A positioning mechanism of an ophthalmologic apparatus for adjusting a height of an optical system of said ophthalmologic apparatus relative to a subject eye, said positioning mechanism comprising:

• (a) an operation knob having a grasping portion which is rotatable around a shaft;
• (b) a detection means for detecting a rotating direction and a rotating speed of said operation knob;
• (c) a driving motor for vertically moving said optical system of said ophthalmologic apparatus;
• and
• (d) a driving motor control means for non-linearly increasing the ratio of the driving speed of said driving motor to the rotating speed obtained by said detection means.

A positioning mechanism of an ophthalmologic apparatus for adjusting a height of an optical system of said ophthalmologic apparatus relative to a subject eye, said positioning mechanism comprising:

• (a) an operation knob having a grasping portion which is rotatable about a center shaft;
• (b) a disc having radial slots and being rotated in synchronism with the rotation of said grasping portion of said operation knob;
• (c) pairs of light-emitting and light-detecting devices, each pair including a light emitting device and a light detecting device in opposition with each other with said disc interposed therebetween, said pairs of light-emitting and light-detecting devices being disposed in positions so that waveforms of the respective outputs of said pairs of light-emitting and light-detecting device are shifted in phase from each other and so that said pairs of light-emitting and light-detecting devices are independent of the rotation of said grasping portion;
• (d) a processing means for obtaining a rotating direction and a rotating speed of said operation knob from the waveforms of the respective outputs of said light detecting devices of said pairs of light-emitting and light-detecting device;
• (e) a driving motor for vertically moving said optical system of said ophthalmologic apparatus;
• and
• (f) a driving motor control means for non-linearly increasing the ratio of the driving speed of said driving motor to the rotating speed obtained by said processing means.