JPS6237368B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a marking method for soft contact lenses, in which a laser beam is irradiated along the line of a predetermined mark on the surface of a swollen soft contact lens, especially on the surface of the peripheral area other than the optical part. By forming a concave part on the soft contact lens, marking work on the soft contact lens can be performed extremely smoothly.Moreover, the concave mark formed in this way can be used even when the surface of the soft contact lens is wet. To provide a marking method for soft contact lenses that enables marking of soft contact lenses to be recognized extremely clearly even when the contact lens is not wet with water.

Conventionally, marking of soft contact lenses has been done by making soft contact lenses in advance by adding a coupling component to a soft contact lens material containing 2-hydroxyethyl methacrylate as a main component, and then placing the soft contact lenses in a diazonium salt solution. In some methods, colored marks are formed by immersing the lens in water and irradiating it with ultraviolet rays, etc., or by engraving the surface of a dry soft contact lens to form recesses, and then creating a soft contact lens material in which a pigment is contained in the recesses. A method has been proposed in which the surface of the filled portion is coated with a soft contact lens material.

However, with this colored marking method for soft contact lenses, the colored marks may change color after a long period of time due to exposure to sunlight, etc., and the coloring agent may be eluted when the soft contact lenses are sterilized by boiling. There are also drawbacks, such as the fact that the surface of the soft contact lens may be eroded because a solvent or the like is used for marking, which reduces the optical properties of the soft contact lens.
Furthermore, since only the mark part of the soft contact lens is colored, this colored part may cause the wearer to look abnormal when wearing the soft contact lens in the eye. Contact lenses also have the disadvantage of lowering their commercial value.

Therefore, in order to form the above-mentioned defect-free marks on soft contact lenses, an extremely primitive method is required, but the surface of the soft contact lens is dried and made easy to engrave, just as in the case of hard contact lenses. It has been found that a concave mark formed by engraving a mark is desirable for soft contact lenses, but such an engraving method not only requires skilled technique, but also The disadvantage is that the strength of soft contact lenses is significantly reduced, resulting in poor durability. In particular, even with a skilled technician, the depth of the recessed part of the mark tends to be deep, which tends to result in poor wearing comfort. Moreover, when the surface of a soft contact lens is wet, the concave mark formed by this engraving method becomes even more difficult to read than when it is dry. Moreover, when forming a mark, the soft contact lens must be dried to avoid wrinkles or other distortions, so the preparation work for forming the mark is extremely troublesome, and the work efficiency is extremely low. low.

The present invention completely eliminates the above-mentioned drawbacks, and examples thereof will be described below.

After making a soft contact lens from a water-swellable material containing 2-hydroxyethyl methacrylate as its main component, the soft contact lens is placed in water to swell sufficiently, and after swelling, it adheres to the surface of the soft contact lens. After wiping off the water, confirm that the soft contact lens in this state is an acceptable product, measure the lens data such as the base curve, and check the soft contact lens in the swollen state with no water attached to the surface. For example, a pulsed carbon dioxide TEA laser type with an output wavelength of 10.6 is placed on the peripheral part other than the optical part.
μm, output coupler is 70% reflective germanium optis, energy density is ~0.3J/cm ² , beam divergence angle is 10mR (full opening angle), beam shape is 21cm×
Using a pulse oscillation laser of 23 cm, pulse duration ~1 μsec, and output energy of 2.8 to 4.0, e.g. 3.3 J, the laser beam is irradiated along the line of the value mark of the measured lens data, and the thickness of the peripheral area is determined by e.g. A concave mark with a depth of about 0.005 to 0.02 mm, for example about 0.017 mm, is formed on the surface of a soft contact lens of about 0.321 mm.

The soft contact lens mark obtained in this way will be formed only on soft contact lenses that have passed the test, so the work efficiency of marking lens data measured after swelling will be further improved, and the marking cost will be reduced. becomes cheaper. On the other hand, even when marking with a laser beam, if the soft contact lens is not marked in a swollen state as in this example, the size of the mark after swelling must be predicted before irradiation with the laser beam. For this reason, the laser beam irradiation may be too large or too small, and furthermore, if the mark is formed in a non-swelled state, if the soft contact lens with the mark formed is swollen. The mark is also enlarged, resulting in poor clarity and precision of the mark. In other words, when attempting to form a mark on a soft contact lens by laser beam irradiation in an unswollen state, the predicted mark formed is often different from the mark after swelling, so even if the soft contact lens itself is a good product, If a soft contact lens is rejected due to a defective mark, the following drawbacks will occur. By irradiating the swollen soft contact lens with a laser beam after removing the water adhering to the surface of the soft contact lens, clear marks of the desired size can be precisely formed, further increasing the work efficiency of mark formation. The results were excellent, and the mark passing rate was extremely high. Furthermore, in order to measure lens data such as the base curve of a soft contact lens, it is meaningless unless it is performed in a swollen state, and after measurement in this swollen state, the soft contact lens must be irradiated with a laser beam immediately without drying it. Since the marking process can be done using the contact lenses, the troublesome process of drying the soft contact lenses to prevent wrinkles and other distortions is no longer necessary.
Marking work becomes extremely smooth and efficient. In addition, since a laser beam is used for marking, unlike the case of engraving, which forms concave marks during drying, the depth of the concave marks can be easily reduced to about 1/20 of that of engraving methods. Therefore, since the depression is shallow, it is difficult for eye oil etc. to adhere to the soft contact lens, and the soft contact lens is less likely to get dirty.The shallow depression also makes the soft contact lens comfortable to wear, and the tensile strength is also low. No. Furthermore, the concave mark formed by irradiating a laser beam onto a swollen soft contact lens after wiping off the water adhering to its surface allows the contents of the mark to be read extremely clearly even when the soft contact lens surface is wet. This is extremely convenient when trying to determine the base curve of a soft contact lens from the marks formed on the soft contact lens.

As described above, the soft contact lens marking method according to the present invention forms concave marks on the surface of the soft contact lens by irradiating the swollen soft contact lens with a laser beam to form concave portions. Therefore, a concave mark with an extremely shallow depth can be formed extremely accurately and clearly, easily and with good workability, and the marking cost is extremely low, and since no pressure is applied to the soft contact lens during the marking process. For example, the depth of the concave mark can be made extremely shallow without causing abnormalities in characteristics such as the base curve, so the comfort of wearing is extremely excellent.Also, even if eye oil etc. adheres to the concave mark part, the concave mark will not be removed. Since the depth of the contact lens is shallow, it can be easily removed, and even if a concave mark is formed, the strength of the soft contact lens will not decrease significantly. The contents can be read extremely clearly, and the mark fully fulfills its purpose.For example, when trying to determine the size of a base curve, etc. from the mark formed on the surface of the convex part of a soft contact lens. It has the advantage of making reading work extremely easy.

Claims (1)

[Scope of Claims] 1. A method for marking a soft contact lens, which comprises forming a concave mark on the surface of a soft contact lens by irradiating a swollen soft contact lens with a laser beam to form a concave portion. 2. The method for marking a soft contact lens according to claim 1, wherein a laser beam is irradiated onto the portion of the swollen soft contact lens surface from which water has been removed.