Sharing Knowledge of progressive multifocal lens

Progressive multifocal lens fitting technology, optical industry in recent years has been a relatively hot topic. The author from the progressive multifocal lenses begin the basic concepts and identify and share relevant experience with knowledge.

     A progressive multifocal lens of the basic identity

     If a single optical lens will be from the appearance of progressive multifocal lenses with the comparison, the biggest difference between progressive multifocal lenses than on the surface of explicit and implicit tags, and there is no single optical lens. If you want progressive multifocal lens of experience with understanding, they must be familiar with the identity of the lens. The figure is the basic identity of a brand of lens.

     1.1 The dominant and recessive markers

     On the surface of the lens are generally two kinds of explicit and implicit tags. As the name implies, dominant markers are available directly observed the naked eye, and the need to wipe out the; and hidden tags, you need the help of sunlight or the light to see through the careful identification and retained in the lens in a lifetime. Figure 1, a black mark for the dominant marker, and the white mark was hidden.

     1.2 The role of dominant marker

     a. glasses Cross: If IPD and the pupil of high measurement accuracy, glasses and customer cross is the corresponding pupil. Thus, by observing the mutual glasses Cross and the position of the pupil may largely determine the accuracy of measurement. So, together with the glasses, including all dominant marker cross, we must wait until after the customer tried on before and no apparent problems wipe out.

     b. Reference circle far: 4mm at the top in cross glasses. Far from here with the luminosity measurement lens is the most accurate.

     c. prism reference point: at the bottom of glasses 4mm at the cross. As progressive multifocal lenses above and below the degree and the thickness is inconsistent, from the aesthetic point of view, to obtain the thickness of the top and bottom are basically the same, and thus processing in the garage down the bottom will be a prism. In general, the degree of prism lenses under the same number of additional luminosity is directly proportional to the luminosity increases the number of under about one-half to two-thirds. Through the prism reference point to measure accurately the actual prism lens degree, its significance is that if two prism lenses for more than 2 degrees, then the customer is more difficult to adapt.

     Near circle d. Reference: the reference point at the bottom of the prism. With much the same with the reference circle, near the lens with a reference circle is a measure of the degree and with ADD near the most accurate place; In addition, customers look through the recent past are mainly used for reference circle of view, therefore, the choice of the frame, processing signs of the times necessary to note, should be the almost complete circle with reference to preserved, otherwise they will see almost a direct impact on the visual effects. Near circle with reference to the general diameter of 4mm.

     e. Dispensing Height: Cross from glasses to nearly one-half circle with a reference at the call of the glasses lens height, this is a very important concept, in the frames of the selection and the measurement of high pupil has a very important significance. For example, a brand of glasses lens height of 18mm, retained the top if the glasses Cross 10mm, some of which look far for the 10mm, should select at least how much vertical height of frame was appropriate? A simple calculation of the 10mm lens glasses with the height of 18mm, plus nearly half circle with a reference that is 2mm, the height should be selected at least 30mm or more had just the right frame. Similarly, if a glasses lens height 14mm, select the height can be 26mm or more frames. Therefore, the smaller the height of glasses, then the more broad selection of frames. Similarly, high pupil must be equal to or greater than the selected height with 2mm lens glasses before, or only re-select the frame or change the location of wear.

     f. level of marking: Cross in the glasses and the prism reference point on each side of the two levels of short-term, these four short-term will help us determine whether the installation of the lens in a horizontal position and whether there are tilt.

   1.3 The role of recessive markers

     a. Invisible Marking: In the prism reference point on each side of a small circle, known as stealth engraving. The two stealth engraved on the handling of complaints will play a significant role. As shown above, the distance between the two Stealth Marker is 34mm, while the average separation of the prism reference point, each hidden from the prism reference point engraving is 17mm. Because the prism reference point from all dominant markers are fixed values, so long as the two Stealth Marker to find out, can wipe out all of the dominant marker to be fully restored it. The process of recovery does not require holding a dominant marker ruler to measure, with a call measurement card (Figure 2) tools can be marked out of a very easy recovery.