The correct way to use the focimeter:
The focimeter is the main testing equipment for spectacles. It is used to measure the vertex power of spectacle lenses, determine the axial direction of the cylindrical lens of astigmatic lenses, and print marks on the optical center of the lenses. The operator's operation is wrong or irregular, which will directly affect the accuracy of the measurement, resulting in unqualified glasses. Correct use of the focimeter is the key to fitting qualified glasses.
Autofocus focimeters are the most widely used type of focimeters. This document takes autofocus focimeters as an example:
1. Preparation before measurement
a) Turn on the switch of the focimeter to warm up. After a period of warm-up, start to detect the fitted glasses.
b) The inspector sits in front of the focimeter, puts the glasses on the lens holder of the focimeter, the eyes are just on the lens holder of the focimeter, put down the lens holder, and fix the glasses;
c) Turn the moving handle of the lens stage with the right hand, and let the lens stage slowly lean against the glasses to be tested. At this time, the nose pad of the frame matches the simulated nose bridge of the focimeter;
d) The inspector holds the glasses with their left hand at the same time to keep the glasses in a horizontal state.
2. Determination of vertex power value
a) Turn the lens table moving handle with the right hand to move the lens table, the lens table pushes the glasses to move vertically, and the lens table moves at a constant speed; the left hand pushes the glasses to move carefully in the horizontal direction;
b) Move the optical center of the spectacle lens to coincide with the cross line of the power plan reticle, (the cross line will become the largest at this time) press the memory button to lock the number displayed on the display, which is the spectacle lens vertex power value.
c) To measure the fitted glasses, in order to prevent the left and right lenses from being confused, at any time, adhere to the principle of the right first and then the left, that is, first detect the right lens of the glasses, and then the left lens.
d) Dot the optical center of the spectacle lens with an inker.
e) Move the fitting glasses to the left lens and perform the same process.
f) The horizontal distance of the optical center, the horizontal mutual difference of the optical center, and the axial direction of the astigmatic lens have been given at the same time when measuring the vertex power value. The optical center vertical mutual difference does not give a result at once, it needs further measurement.
3. Optical center vertical mutual difference:
a) The vertical mutual aberration of the optical centers shows that the horizontal heights of the optical centers of the two lenses are inconsistent, one eye is high and the other is low.
b) The optical centers of the left and right lenses are on two parallel straight lines L1 and L, so the vertical mutual difference between the optical centers cannot be directly measured, but we assume that: move the vertical line L of the optical center of the right lens to the vertical line L1 of the optical center of the left lens in parallel , to coincide, which becomes the measurement of the distance between two points on a straight line.
c) Find the optical center of the lens of the right lens of the glasses, mark it with the inker, mark A: Then move the glasses to the left lens in the horizontal direction, do not turn the moving handle of the lens table at this time, just slightly adjust the horizontal direction of the left lens to the optical center of the left lens On the vertical center line L1, the inker marks A1, A1 is supposed to move horizontally to the optical center A of the right lens, reach the position behind the vertical line L1 of the left lens, turn the moving handle of the lens table, and the lens table pushes the glasses to move vertically to the left lens the light
The center of the study, dotted with the inker, marked B, point B is also the position of the optical center of the left lens in the vertical direction, and the distance between A1B is the vertical mutual difference between the optical centers of the glasses.
4. How to ensure the accuracy of the measured values:
a) When measuring the vertex power value of the lens, the display screen will show the prism value of the lens at the same time. The prism value is generated because the optical center of the lens and the optical axis of the focimeter are not on the same vertical axis. The measured value is accurate, and the torque should be memorized at the minimum value of the prism. (The company requires the reading when the horizontal and vertical prism degrees are less than 0.1)
5. About the setting of the focimeter:
a) The focimeter can set parameters such as accuracy, lens type, lens Abbe number, etc.;
b) In general, the precision is set at 0.01D, the lens type is selected as a single-focal resin lens, and the Abbe number is set at the lowest value. In special cases, the setting can be changed according to requirements and lens type.
6. The method of measuring the vertex power of the lens is similar to that of measuring the vertex power of the assembled glasses.
7. The focus meter shall be maintained and maintained by the company's designated manager, and the maintenance method shall be carried out according to the equipment manual.