Focus meter classification

Lens meters can be classified according to different characteristics such as measurement principle, measurement range and application field. The following is a classification of common focimeters based on these characteristics:
1. Classification based on measurement principles:
- Optical focimeter: obtains foci information by measuring the refraction or reflection of light in a transparent medium, such as spherical refraction, self-focusing Law etc.
- Mechanical focimeter: Obtain foci information by measuring the force or displacement relationship between the object and the measuring device, such as Newton's ring method, speaker diaphragm method, etc.
- Electronic focimeter: obtain foci information by measuring changes in electrical properties such as capacitance, inductance or impedance, such as suspended electrode method, capacitance measurement method, etc.
2. Classification based on measurement range:
- Small focimeter: suitable for measuring a smaller foci range, such as micro lens focimeter, thin lens measuring instrument, etc.
- Medium focimeter: suitable for measuring medium focal range, such as Fuchs focimeter, white noise focimeter, etc.
- Large focimeter: suitable for measuring larger focal ranges, such as medical ophthalmoscopes, high-power microscopes, etc.
3. Classification according to application fields:
- Optical field: used to measure the power of optical components such as lenses, objectives, camera lenses, etc.
- Materials Science: Used to measure the refractive index of transparent materials (such as glass, plastic, etc.) to calculate their power.
- Medical field: used to measure the refractive power of the eye and help diagnose eye diseases such as refractive errors.
-Industrial applications: used to measure automatic focus adjustment systems, measure the focal length of precision components, etc.
It’s important to note that this is just a common way to classify focus meters, and they can actually be classified based on other characteristics.