METHOD FOR MACHINING A LENS AND ADHESIVE LABEL USEFUL WHEN MACHINING THE LENS BACKGROUND OF THE INVENTION

1. Field of the Invention This invention relates to a method for machining a lens, more particularly to a method for machining a lens that is formed with a grid pattern thereon.

2. Description of the Related Art

A conventional method for machining a lens, such as an eyeglasses lens, includes the steps of: determining an optical center of the lens; marking the optical center of the lens; determining a curvature center of the lens; marking the curvature center of the lens; marking the lens, with respect to the optical center and the curvature center of the lens , with a border line that conforms to the shape of an eyeglasses frame; and machining the lens. The aforementioned conventional method is disadvantageous in that, since step (E) is performed manually, the process is prone to error, time consuming, inaccurate, and irreproducible . SUMMARY OF THE INVENTION Therefore, the object of the present invention is to provide a method for machining a lens capable of overcoming the aforesaid drawbacks of the prior art.

According to one aspect of the present invention, a method for machining a lens comprises the steps of: determining an optical center of the lens; marking the optical center of the lens; determining a curvature center of the lens; marking the curvature center of the lens; and providing the lens with a grid pattern having a grid center that is aligned with the optical center of the lens, and a grid line that passes through the grid center and the curvature center of the lens.

According to another aspect of thepresent invention, an adhesive label comprises a transparent sheet, an adhesive layer, andagridpattern. The transparent sheet has opposite first and second surfaces. The adhesive layer is applied to the first surface of the transparent sheet . The grid pattern is printed on the second surface of the transparent sheet . BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:

Figure 1 is a schematic view of the first preferred embodiment of an adhesive label according to the present invention;

Figure 2 is a sectional view of the first preferred embodiment ;

Figures 3 to 9 are schematic views to illustrate different shapes and sizes of the first preferred embodiment ;

Figure 10 is a schematic view of the second preferred embodiment of an adhesive label according to the present invention;

Figure 11 is a schematic view of the third preferred embodiment of an adhesive label according to the present invention; Figure 12 is a flowchart of the first preferred embodiment of a method for machining a lens according to the present invention;

Figure 13 is a perspective view to illustrate a lens; Figure 14 is a sectional view to illustrate a state where a first release sheet of the adhesive label is peeled off;

Figure 15 is a sectional view to illustrate a state where a transparent sheet of the adhesive label is attached to the lens; Figure 16 is a perspective view of Figure 15;

Figure 17 is a sectional view to illustrate a. state where a second release sheet of the adhesive label is peeled off;

Figure 18 is a flowchart of the second preferred embodiment of a method for machining a lens according to the present invention; and

Figure 19 is a perspective view to illustrate an

erasable grid pattern printed on the lens; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before the present invention is described in greater detail , it should be noted that like elements are denoted by the same reference numerals throughout the disclosure.

Referring to Figures 1 and 2, the preferred embodiment of an adhesive label according to this invention is shown to include a transparent sheet 2, a crosshair, a grid pattern 27, a first adhesive layer 3, a first release sheet 4, a second release sheet 6, and a second adhesive layer 5.

The adhesive label is use for machining a lens 1 (see Figure 13) , such as an eyeglasses lens, in a manner that will be described in greater detail hereinafter.

The transparent sheet 2 has opposite first and second surfaces 21, 22.

The crosshair is printed, by a printing machine, on the second surface 22 of the transparent sheet 2, and includes horizontal and vertical lines 24, 25 that cross at a crosshair center 23.

The grid pattern 27 is printed, by a printing machine , on the second surface 22 of the transparent sheet 2, and is symmetrical with respect to the horizontal and vertical lines 24 , 25 of the crosshair . In this embodiment , the grid pattern 27 has a grid center that serves as the crosshair center 23 of the crosshair, a grid line

that passes through the crosshair center 23 and that serves as the horizontal line 24 of the crosshair, a plurality of solid horizontal lines, each of which is parallel to the horizontal line 24 of the crosshair, and a plurality of solid vertical lines, each of which is parallel to the vertical line 25 of the crosshair. It is noted that the horizontal and vertical lines of the grid pattern 27 may have different thicknesses or colors for easy identification. The first adhesive layer 3 is applied on the first surface 21 of the transparent sheet 2.

The first release sheet 3 is adhesively attached to the first adhesive layer 3, and covers the first surface 21 of the transparent sheet 2, thereby permitting the adhesive label to be transported conveniently.

The second release sheet 6 is transparent, and covers the second surface 22 of the transparent sheet 2 for protecting the grid pattern 27.

The second adhesive layer 5 is applied to the second release sheet 6 , and is adhesively attached to the second surface 22 of the transparent sheet 2 when the second release sheet 6 covers the second surface 21 of the transparent sheet 2.

It is noted that the first and second release sheets 4, 6 have end portions 41, 62 that are connected to each other. The construction as such permits sequential removal of the first and second release sheets 4, 6 from

the transparent sheet 2.

The grid pattern 27 may be of different shapes and sizes. As illustrated in Figure 3, the grid pattern 27 includes a grid 271 that covers the whole quadrant of the crosshair. As illustrated in Figure 4, the grid pattern 27 includes left and right grids 271, 272, each of which is disposed at a respective one of the opposite sides of the vertical line 25 of the crosshair, and a middle grid 273 disposed between the left and right grids 271, 272. As illustrated in Figure 5, the grid pattern 27 includes a first pair of rectangular grids 271, 271' , each of which is disposed at the respective one of the opposite sides of the vertical line 25 of the crosshair, and a second pair of rectangular grids 272, 272' , each of which is disposed at a respective one of the opposite sides of the horizontal line 24 of the crosshair and eachof which interconnects the first pair of rectangular grids 271, 271' . As illustrated in Figure 6, the grid pattern 27 includes a pair of rectangular grids 271, 272, each of which is disposed at the respective one of the opposite sides of the vertical line 25 of the crosshair. As illustrated in Figure 7, the grid pattern 27 includes a pair of hexagonal grids 271, 272, each of which is disposed at the respective one of the opposite sides of the vertical line 25 of the crosshair. As illustrated in Figure 8, the grid pattern 27 includes a pair of circular grids 271, 272, each of which is

disposed at the respective one of the opposite sides of the vertical line 25 of the crosshair. As illustrated in Figure 9, the grid pattern 27 includes a pair of sector-shaped grids 271, 272, each of which is disposed at the respective one of the opposite sides of the vertical line 25 of the crosshair.

Figure 10 illustrates the second preferred embodiment of an adhesive label . When compared with the previous embodiment, the adhesive label includes a pair of the grid patterns 27, 27' . As such, the transparent sheets 2 of the adhesive label may be simultaneously attached to a pair of lens. Moreover, the adhesive label further includes a cutting line 8 provided between the grid patterns 27, 27' . In this embodiment, each of the grid patterns 27, 27' includes a plurality of solid horizontal lines and a plurality of solidvertical lines .

Figure 11 illustrates the thirdpreferred embodiment of an adhesive label. When compared with the second preferred embodiment, each of the grid patterns 27, 27' includes a plurality of dotted horizontal lines and a plurality of dotted vertical lines.

The first preferred embodiment of a method for machining the lens 1 with the use of the adhesive label according to this invention will now be described with further reference to Figure 12.

In step 121, an optical center 11 of the lens 1 is determined.

In step 122, the lens 1 is printed with a mark at the optical center 11 of the lens 1.

In step 123, two curvature centers 12 of the lens 1 are determined. In step 124, the lens 1 is printed with a mark at the two curvature centers 12 of the lens 1 t

It is noted that, as illustrated in Figure 13, each of the optical center 11 of the lens 1 and the curvature centers 12 of the lens 1 lies in a principal axis 13 of the lens 1.

In step 125, as illustrated in Figure 14, the first release sheet 4 of the adhesive label is peeled off. In step 126, as illustrated in Figures 15 and 16, the first surface 21 of the adhesive label is attached to the lens 1 such that the crosshair center 23 of the crosshair is aligned with the optical center 11 of the lens 1, and such that the horizontal line 24 of the crosshair is aligned with the curvature centers 12. In step 127, as illustrated in Figure 17, the second release sheet 6 of the adhesive label is peeled off. In step 128, the lens 1 is machined. In step 129, the transparent sheet 2 of the adhesive label is peeled off from the lens 1.

The second preferred embodiment of a method for machining a lens according to this invention will now be described- with further reference to Figure 18.

In step 181, an optical center 11 of the lens 1 is

determined.

In step 182, the lens 1 is printed with a mark at the optical center 11 of the lens 1.

In step 183, two curvature centers 12 of the lens 1 are determined.

In step 184, the lens 1 is printed with a mark at the two curvature centers 12 of the lens 1.

In step 185 , the lens 1 is printed with a grid pattern

27 that defines a grid center 270, which is aligned with the optical center 11 of the lens 1, and a reference grid line 24 , which is aligned with the curvature centers

12 of the lens 1, as best shown in Figure 19.

In step 186, the lens 1 is machined.

In step 187, the grid pattern 27 is erased. From the above description, the present invention has the following advantages.

1. The method for machining of the lens 1 permits machining, such as fine grinding, cutting, boring, polishing, or engraving, both accurately and with good reproducibility.

2. The method for machining of the lens 1 shortens machining operation time and minimizes machining errors , thereby reducing production cost.

3. Not only is the adhesive label inexpensive to produce, the use of conventional machining apparatus (not shown) is also permitted such that no large investment in equipment is needed.

4. When the transparent sheet 2 of the adhesive label is attached to the lens 1, the transparent sheet 2 protects the lens 1 from abrasion during polishing operation. While the present invention has been described in connection with what is considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.