JP3081395B2 - Laser marking method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser marking method for providing a desired mark on a translucent marking object, and can be applied, for example, when a desired mark is provided on a plastic lens.

[0002]

2. Description of the Related Art For example, optical components such as spectacle lenses and mirrors are provided with information on the optical components, such as a model number, a standard, and an indication of a specific position, in order to discriminate between products of the company and products of other companies. A desired mark is provided for display.

[0003] When a mark is given to an optical component, particularly when a mark is given to an eyeglass lens, it is required that the mark is as inconspicuous as possible due to the nature of the product.
As a result, they are usually not recognizable to the naked eye and can be used as needed (eg, by observing from a particular angle).
A so-called hidden mark that can be recognized is provided.

Heretofore, as a marking method for providing such a hidden mark, a method of engraving with a needle made of a hard material such as diamond has been most commonly performed.

However, since the engraving marking is performed by moving a tool along a predetermined marking pattern, the work efficiency is low, the marking takes a remarkably long time, and a large number of objects have the same pattern. There is a problem that the reproducibility when trying to attach is poor. Furthermore, since the marking portion on the surface of the spectacle lens becomes V-shaped due to engraving using a pointed object such as a needle, the light reflection state of this portion is different from other portions. Therefore, there is a problem that the performance as a hidden mark becomes insufficient.

In order to solve such inconveniences, the present applicant focuses a laser beam inside a marking object (for example, a spectacle lens) as disclosed in Japanese Patent Application Laid-Open No. 3-124486. A laser marking method for providing a mark inside this marking object has already been proposed. In this laser marking method, the inside of the marking object is selected as a mark application location so as not to damage a surface treatment film (for example, an organic hard coat film or an inorganic anti-reflection film) on the surface of the marking object. It was done.

[0007]

Problems to be Solved by the Invention
The laser marking method disclosed in No. 6 has an advantage that it can be widely applied to various kinds of light-transmitting members regardless of a marking object and a material of a surface treatment film thereof.

However, in the laser marking method disclosed in Japanese Patent Application Laid-Open No. 3-124486, since only a part of the inside of a marking object made of a uniform material is broken such as melting or alteration, a laser beam is used. However, there is a problem that it is difficult to appropriately adjust the irradiation energy amount and the focal point. That is, the amount of irradiation energy of the laser beam and the focal point are adjusted so that the size and the depth of the mark portion are predetermined and the mark quality is constant while preventing the destruction of the hard coat film and the antireflection film. It was also difficult to adjust.

As described above, Japanese Patent Application Laid-Open No. HEI 3-124486.
Has the advantage that it can be widely applied almost irrespective of the material of the substrate to be marked or the material of its surface treatment film, but also has the above-mentioned slight disadvantages, Even if the application target is limited, if a laser marking method suitable for such an application exists, it can be said that the laser marking method is preferable because it contributes to enrichment of technology.

The present invention has been made in view of the above points, and has as its object to provide a laser marking method in which the adjustment of the irradiation laser beam is easy and a mark can be easily provided. .

[0011]

According to the present invention, there is provided a laser marking method for focusing a laser beam on a marking object to be provided with a mark to impart the mark to the marking object. The object to be marked is a plastic optical component surface-treated with a polysiloxane-based hard coat film and / or an antireflection film, and a laser beam is focused near the surface of the plastic optical component to provide a mark. .

Here, it is preferable that the laser light applied to the plastic optical component has passed through a mask portion including a light shielding portion and an optical window portion having the same shape as the mark figure.

[0013]

According to the present invention, a plastic optical component surface-treated with a polysiloxane-based hard coat film and / or an anti-reflection film is used as a marking object, and the laser light is focused on the surface of the plastic optical component in the vicinity thereof. It breaks (melts, alters) the vicinity of the surface and acts as a mark.

Considering that a surface treatment film such as a hard coat film or an anti-reflection film does not cause scratches or cracks, it is preferable to apply a laser beam to the inside of a marking object to give a mark. However, it is difficult to adjust the laser beam so that the depth and size of the mark are intended, and furthermore, only a part of the inside of the uniform material is destroyed so that the mark quality is uniform. On the other hand, if no scratches or cracks occur on the surface treatment film, it is preferable to focus the laser beam on the surface of the marking target because the adjustment is easier.

[0015]

Therefore, in the present invention, when the plastic optical component is a marking object, the laser light is focused on the surface of the plastic optical component in consideration of the simplicity in terms of adjustment of the laser light and the like. It was decided to add a mark.

When the laser beam passing through the mask portion formed by the light-shielding portion and the optical window having the same shape as the mark figure is focused near the surface of the plastic optical component, the plastic optical component and the optical system can be focused. This is a preferred embodiment of the present invention, since a mark of a desired figure can be obtained without moving.

[0018]

【Example】

(A) Outline of Laser Marking Method of Example Hereinafter, an example of a laser marking method of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram of the laser marking method of this embodiment.

In FIG. 1, a focusing lens 2 constituting a part of a laser irradiation apparatus is opposed to a plastic lens 1 as a marking object in this embodiment. The plastic lens 1 has a structure in which a hard coat film 4 and an antireflection film 5 are laminated on the surface of a lens substrate 3.

In the laser marking method of this embodiment, a divergent laser beam or a parallel laser beam L is applied to a point P near or on the surface of a lens substrate 3 by a focus positioning lens 2.
The surface of the lens substrate 3 or the vicinity of the surface is altered by the energy of the focused laser beam L so as to function as a mark. That is, the altered portion has a different refractive index, transmittance, or the like from other portions, and can be identified from the outside, and functions as a mark.

[0021]

(B) Configuration for Implementing Laser Marking FIG. 2 shows a plastic lens 1 to be marked.
1 shows a system configuration for adding a mark to a. As shown in FIG. 2, the laser marking system includes a laser irradiation device 10 and a lens holding device 20.

(B-1) Laser Irradiating Apparatus 10 The laser irradiating apparatus 10 controls a laser oscillating unit 11 that oscillates pulsed laser light L, and adjusts the optical path and light amount of the laser light L oscillated from the laser oscillating unit 11. A reflecting mirror 12, a condensing lens 13 which is an optical system for condensing and diverging the laser light L, and a laser light L diverged by the condensing lens 13 for selecting and transmitting as a graphic pattern. (Hereinafter, referred to as a mask) 14 which forms a figured pattern space portion, and three optical path length adjusting mirrors which constitute an optical path adjusting portion for adjusting the optical path length and the like of transmitted light from the mask portion 14. 15 to 17 and the above-described focal position adjusting lens 2 for condensing the transmitted light from the optical path adjusting unit at a point P near the surface of the plastic lens 1 as a marking target, They are provided in the order of the row direction.

Hereinafter, each part constituting the laser irradiation apparatus 10 will be described in detail.

The laser oscillation section 11 has an output wavelength 1
A CO ₂ (carbon dioxide) laser device which oscillates a pulse laser beam L having a pulse width of 0.6 μm and a pulse width of 3 μsec is applied. The reason for using the pulsed laser light L is that by appropriately selecting the number of pulses, it is possible to prevent the transformation due to the irradiation energy of the plastic lens 1 from being excessive or insufficient, and to prevent the surface of the hard coat film 4 and the antireflection film 5 from being deformed. This takes into consideration the provision of a mark without displaying destruction on the processing film.

A resonator mirror having a reflectivity of 70% is provided on the output side of the laser oscillation section 11, and a reflection mirror 12 is provided on a passage of the oscillation laser light L. By adjusting the surface of the reflection mirror 12, the optical axis, optical path length, and the like of the laser beam L are adjusted.

The condensing lens 13 is composed of, for example, a cylinder lens or a plano-convex lens. The condensing lens 13 condenses the oscillated laser light L and then diverges it. The divergent laser light L reaches the mask section 14. The light condensing and diverging processes are performed for the purpose of controlling the laser beam power, and take into account a situation in which the laser beam power is too strong and breaks the surface treatment film of the lens. The divergence processing is performed by the optical path adjusting units 15 to
Together with the function of No. 17, the diameter at the convergence point P is variably defined.

As shown in FIG. 3, the mask portion 14 is provided with a space hole (which may be an optical window) 14b designed in the stencil substrate 14a.
The graphic pattern of the identification mark is determined by the shape of 4b. It goes without saying that the design of the pattern itself is arbitrary. The graphic pattern shown in FIG. 3 is a graphic representation of the character “H”. Here, the stencil substrate 14a is 0.2
It is preferable to have a thickness of not less than mm because light can be surely shielded. When applied to a hidden mark such as an eyeglass lens, the line width of the space hole 14b is most preferably about 0.3 to 0.8 mm. The end of the line of the space hole 14b is represented by the curve R
It is a stop 14c. This is because the mark becomes more beautiful than the corner stop. In addition, in the case of a corner stop, the corner stop portion tends to have a glare effect of reflected light. The cause of the glare effect depends strongly on the laser light dots,
It is presumed that uniformity of the depth and width of the line cannot be obtained at this end portion. Therefore, in the case where the spectacle lens or the like is a marking target, the R-stop form is preferable.

In the laser marking method disclosed in Japanese Patent Application Laid-Open No. 3-124486, a mark (figure pattern) is formed by drawing an optical system or an object to be marked in a direction perpendicular to the optical axis. On the other hand, in the case of this embodiment, as described above, the mask portion 14
The mark is provided without moving the optical system or the object to be marked in the direction orthogonal to the optical axis. This is because marking object is plastic lens 1
This is because the destruction threshold is small, so that the destruction is performed even if the energy density is small to some extent, and the focusing by the focus position adjusting lens 2 may be small. That is, even if the focal position of the focal alignment lens 2, that is, the spot diameter on the surface of the plastic lens 1 is somewhat large, the plastic lens 1 can be destroyed and a mark can be provided. With such a marking method, it is possible to perform marking on one plastic lens 1 simply and in a short time as compared with the laser marking method disclosed in JP-A-3-124486.

An optical path adjusting section comprising three optical path length adjusting reflecting mirrors 15 to 17 which can swing and reciprocate moves the laser light L by appropriately adjusting the surfaces of the reflecting mirrors 15, 16 and 17. And the diameter of the convergence point P is varied.

The focusing lens 2 is provided with a laser beam L at a point P near the surface of a plastic lens 1 which is a marking object which is separated from the lens 2 by a predetermined distance.
Is collected.

(B-2) Lens Holder 20 The lens holder 20 includes a lens mounting table 21, a lens convex surface fixing positioning plate 22, a mounting table movable mechanism 23, and the like.

This embodiment is based on the premise that a plastic lens 1 to be marked is a meniscus lens used as a spectacle lens or the like, and the lens mounting table 21 mounts the plastic lens 1 so that its concave side faces down. Is placed.

A lens convex surface fixing positioning plate 22 is provided to press and hold the plastic lens 1 mounted on the lens mounting table 21 from below. The holding device for applying a pressing force to the plate 22 is not shown. As shown in FIG. 4, the lens convex surface fixing positioning plate 22 has a circular flat space 22b formed in a flat plate portion 22a. Space part 2
2b is for naturally exposing the portion of the plastic lens 1 to be marked to the outside of the plate 22 toward the focus position adjusting lens 2.

The position of the plastic lens 1 exposed in the space 22b of the plate 22 in the plane direction where the mark M is provided is, as shown in FIG. Has been selected. The gimbal mechanism described later adjusts the tangent plane of the exposed portion so as to be orthogonal to the optical axis of the optical system.

An elastic ring 22c is attached to the peripheral edge of the space 22b of the plate 22, that is, the portion that comes into contact with the convex surface of the plastic lens 1, and the lens convex surface fixing positioning plate 22 holds the plastic lens 1 in place. Even when pressed and fixed, the elasticity of the ring body 22c prevents the lens surface from being damaged.

The lens mounting table 21 is attached to a mounting table movable mechanism 23 which is provided below and includes a vertically movable mechanism and a gimbal mechanism. That is, the lens mounting table 21 can be moved not only vertically but also tilted in all directions by the mounting table movable mechanism 23 so as to correspond to the fixing of the convex surface of the plastic lens 1. As the gimbal mechanism, for example, a lens processing layout apparatus (centering machine CM31 manufactured by Hoya Co., Ltd.) for performing optical layout of spectacle lenses
The same gimbal mechanism as disclosed in Japanese Patent Application Laid-Open No. 60-165141 can be applied. In particular, in the case of spectacle lenses, the power (ie, radius of curvature) of the lens differs depending on the patient's prescription. As a method of responding to such a difference for each marking target, there is a method of changing the focal length of the focal alignment lens 2 every time the prescription of the plastic lens 1 changes. However, it is a complicated operation, and the cost is high for mass production technology. Therefore, in this embodiment, the gimbal mechanism of the lens mounting method with the convex surface fixed is used without changing the focal length to respond to the difference of each marking target.

(C) Irradiation Conditions and Function of Laser Beam When marking is performed on the plastic lens 1 by the laser marking method of the embodiment, the laser is held in a state where the plastic lens 1 is fixed at a predetermined position by the laser holding device 20. Irradiation with light L is performed.

Hereinafter, an example of laser light irradiation conditions for appropriately performing marking will be described together with the operation of the laser light L.

Laser oscillation unit (CO ₂ laser device) 11
Is a laser beam having an output wavelength of 10.6 μm and a pulse width of 3 μsec, and has an energy per pulse of 2.2 to 2.2.
4.0J / PULSE, average energy about 3.2J
A laser beam L of about / PULSE is oscillated. In addition,
The energy of the oscillating laser light L is
1 changes depending on the drive voltage. After the oscillation laser light L has its optical path bent by the reflection mirror 12 and is slightly attenuated, for example, the focal length f is 100 m.
m, effective diameter D is 50.8 mm, and opening half-angle 開口 is 6.27.
The light is condensed and diverged through a condensing lens 13 which is a plano-convex lens having an angle of °.

The diverged laser light L passes through the mask section 14. The laser beam L that has passed through the mask section 14 has a spot shape designed to some extent at this point. The laser beam that has passed through the mask unit 14 is reflected by the reflection mirror 1
The light is adjusted to an appropriate optical path length while using the lenses 5 to 17 and enters the focal position alignment lens 2.
Focus on a position P (see FIG. 1) at 0 mm. When the distance to the point P is set to 130 mm, the tolerance of the distance is about ± 1 mm.

When the laser light L is focused on the point P near the surface of the plastic lens 1, the beam diameter of the laser light L on the surface of the plastic lens 1 is 2 to 4 mm.
Further, since the entire energy of the laser beam is concentrated at the point P, the energy density is estimated to be several hundreds to several hundreds (an example of an actually measured value is 1360) mJ / cm ² .

The breaking threshold of the lens substrate 3 inside the plastic lens 1 (for example, 5 to 5 in the case of an acrylic lens composition)
40 mJ / cm ² or so, the diethylene glycol bis allyl carbonate type lens, about 35 mJ / cm ² or less, much larger than these smaller energy) is a polyurethane lens.

On the other hand, the destruction threshold of the surface of the antireflection film 5 is:
Although it differs depending on the film composition and the optical film thickness of the antireflection film 5, JP-A-3-1244 filed separately by the present applicant.
As disclosed in Japanese Unexamined Patent Publication No. 86-86, data measured using a YAG laser is based on a multilayer antireflection film (4000 Å) of a SiO ₂ film and a ZrO ₂ film generally used for an eyeglass lens or the like. About 5000mJ / cm
^The value is about 2, and it is estimated that the antireflection film 5 and the organic hard coat film 4 of other composition systems have substantially similar values.
Further, the hard coat film 4 and the antireflection film 5 are transparent, and have a light transmittance characteristic that they hardly absorb the energy of the laser beam (hardly cause destruction).

As a result, only the point P near the surface of the lens substrate 3 has a width of 200 to 400 μm and a depth of 100 to 250 μm.
Deterioration occurs over a range of degrees (see FIG. 6). As a result, the refractive index, transmittance, and the like of the altered portion become different from those of the other portions , so that the altered portion can be identified from the outside and functions as a mark.

A preferable laser marking method is as follows.
This is a method in which the drive voltage of the laser oscillation unit 11 is reduced and the number of shots (number of pulses) is increased. That is, the plastic lens 1 which is an object to be marked several times with weak energy
Is preferably irradiated with laser light L so that only the lens substrate 3 is destroyed without excess or deficiency.

(D) Description of Marking State of Plastic Lens FIG. 6 shows an uneven state of the surface of the plastic lens 1 after the laser beam L is irradiated under the above-described irradiation conditions and marking is performed. The application experiment will be described later), FIGS. 6 (A1) to 6 (A3) show the unevenness of the mark portion, and FIG. 6 (B) shows the unevenness of the portion other than the mark portion.

FIG. 6 shows the results obtained by scanning the surface of the plastic lens 1 with a tracing stylus by Tarisurf of Rank Hobson Taylor Co. to measure the line width and depth of the mark.
In FIG. 6 (A1) ~ (A3) , a portion where the convex portion surface is melted by the laser beam is modified, and that the convex portion undergoes an optical on birefringence, causing recognition acts as a mark presume. This convex part, that is,
The mark part is about 200-400 µm wide and about 100-depth
It is about 250 μm. In addition, as shown in FIG. 6B, naturally, no convex portion occurs except for the mark portion.

It should be noted that even if a convex portion is formed on the surface of the plastic lens 1, the hard coat film 4 and the antireflection film 5 having the compositions described later do not cause scratches or cracks .

(E) Material and the like of the plastic lens 1 When marking the plastic lens 1 as a marking object, the lens substrate 3 and the hard coat 4
If the antireflection film 5 is at least as follows, the laser marking method of the above-described embodiment, that is, the method of providing a mark on the surface of the lens substrate 3 can be applied.

(E-1) Lens Substrate 3 As the applicable lens substrate 3, a synthetic resin substrate (plastic substrate) can be exemplified. As the synthetic resin, methyl methacrylate homopolymer, methyl methacrylate and 1
A copolymer containing at least one other monomer as a monomer component, a diethylene glycol bisallyl carbonate homopolymer, a copolymer containing diethylene glycol bisallyl carbonate and at least one other monomer as a monomer component, and a sulfur-containing copolymer. Coalescence, halogen-containing copolymer, polycarbonate, polystyrene, polyvinyl chloride, unsaturated polyester, polyethylene terephthalate, polyurethane and the like.

(E-2) Hard Coat Film 4 Examples of the hard coat film 4 of the plastic lens 1 suitable for applying the laser marking method of the embodiment include a polysiloxane-based hard coat film.

As the polysiloxane-based hard coat film, those having a composition containing the following organosilicon compound are particularly preferable.

Formula (R ₁ ) _a (R ₂ ) _b Si
(OR ₃ ) _{4- (a + b)} wherein R ₁ and R ₂ are an alkyl group having 1 to 10 carbon atoms,
An organic group having an aryl group, an alkyl halide, an aryl halide, an alkenyl, or an epoxy group, a (meth) acryloxy group, a mercapto group, or a cyano group, which is bonded to silicon by a Si—C bond; ₃ is an alkyl group having 1 to 6 carbon atoms, an alkoxyalkyl group or an acyl group, and a and b are each 0,
1 or 2, and a + b is 1 or 2.

Examples of these compounds include methyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxyethoxysilane, methyltriacetoxysilane, methyltripropoxysilane, methyltryptoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane. Silane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, γ-chloropropyltrimethoxysilane,
γ-chloropropyltriethoxysilane, γ-chloropropyltripropoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ -(Β-glycidoxyethoxy) propyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3
4-epoxycyclohexyl) ethyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane , N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, trialkoxy or triacyloxysilanes such as β-cyanoethyltriethoxysilane, and dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenyl Methyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylphenyldimethoxysilane, γ-glycidoxypropylphenyldiethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane Dialkoxy such as silane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane Silane or diacyloxysilanes can be mentioned.

Further, not only compositions having these organosilicon compounds alone, but also compositions having a combination of two or more kinds can be mentioned.

Furthermore, various tetraalkoxysilanes or hydrolysates thereof can be used in combination with the above-mentioned organosilicon compounds, although they are not used alone.
Examples of such tetraalkoxysilanes include methyl silicate, ethyl silicate, n-propyl silicate, isopropyl silicate, n-butyl silicate, sec-butyl silicate and t-butyl silicate.

Further, these organosilicon compounds can be cured without a catalyst, but various catalysts can be used to further promote the curing.
Examples of such a catalyst include various acids or bases including Lewis acids and Lewis acid salts, or organic carboxylic acids, chromic acid, hypochlorous acid, boric acid, bromic acid, selenous acid, thiosulfuric acid, orthosilicic acid, thiocyanic acid. Metal salts such as acid, nitrous acid, aluminate and carbonic acid, particularly alkali metal salts or ammonium salts, and alkoxides of aluminum, zirconium or titanium, or complex compounds thereof can be used.

Further, the above-mentioned organosilicon polymer can be used in combination with another organic substance. Examples of the other organic substance to be used in combination include an epoxy resin, an acrylic copolymer, and a hydroxyl group-containing polymer such as polyvinyl alcohol. Can be mentioned.

As other formed components, colloidal sols of inorganic oxides such as Si, Al, Ti, Sb, Sn, etc., as disclosed in Optica Acta (published in July, 1962, page 251), may be used. Sol or the like can be used.

Further, in order to facilitate the coating operation, it is also possible to use solvents and various additives for maintaining a good storage state.

The above-mentioned coating composition can be applied and cured on the lens substrate 3 to form the hard coat film 4. Curing of the coating composition is performed by hot-air drying or active energy ray irradiation.
It is good to carry out in hot air of 70 to 200 ° C, particularly preferably 90 to 150 ° C. Note that the active energy rays include far infrared rays and the like, and damage due to heat can be suppressed low.

As a method for forming the hard coat film 4 made of the above-mentioned coating composition on the lens substrate 3, a commonly used method such as a dipping method, a spin method, and a spray method can be applied. From the viewpoint, the dipping method and the spin method are particularly preferable.

Further, before applying the above-mentioned coating composition to the lens substrate 3, a chemical treatment with an acid, an alkali, various organic solvents, a physical treatment with plasma, ultraviolet rays, etc., a detergent treatment with various detergents, By performing a primer treatment using various resins, the adhesion between the lens substrate 3 and the hard coat film 4 can be improved.

(E-3) Antireflection film 5 The antireflection film 5 provided on the hard coat film 4 (or the lens substrate 3) to which the laser marking method of the embodiment can be applied is not particularly limited. That is, a single-layer or multilayer antireflection film 5 composed of a conventionally known inorganic oxide vapor-deposited film can be used. Examples of the antireflection film 5 include, for example, JP-A-2-262104,
JP-A-116003 can be mentioned.

A part of the hard coat film 4 described above can be used as a part of the antireflection film 5 as a high refractive index film, and further, by adding a functional component such as anti-fogging, photochromic, anti-fouling, etc. It can also be used as

(F) Marking Experiment (F-1) Lenses to be Tested Four types of plastic lens substrates of type 1 to type 4 shown below, and three types of hard coat films of type 1 to type 3 shown below And type 1 and type 2 shown below
The marking application experiment was performed using six types of lenses (tested lenses (1) to (6)) shown in the table of FIG. 7 in which the two types of antireflection films were combined.

(F-1-1) Type of Lens Substrate 3 As described above, various synthetic resin substrates can be used as the lens substrate 3. The plastic lens 1 made of the lens substrate 3 was used as a marking target in the marking application experiment.

(F-1-1-1) Type 1 of Lens Substrate 3 Polydiethylene glycol bisallyl carbonate is used as a main component, and 2-hydroxy-4-n is used as an ultraviolet absorber.
-A lens substrate 3 having a refractive index of 1.499, which contains optoxybenzophenone so that the weight ratio of the former to the latter becomes 99.97% to 0.035, is referred to as type 1. The lenses under test (1) and (2) employ the lens substrate 3 of this type 1.

(F-1-1-2) Type 2 of lens substrate 3 30 parts by weight of diethylene glycol bisallyl carbonate, 20 parts by weight of benzyl methacrylate, 45 parts by weight of diallyl isophthalate and 5 parts by weight of methyl methacrylate are used as starting materials. The lens substrate 3 having a refractive index of 1.549 is referred to as type 2. The lenses under test (3) and (4) employ this type 2 lens substrate 3.

(F-1-1-3) Type 3 of lens substrate 3 Xylene diisocyanate, tolylene diisocyanate and pentaerythritol (2 mercaptoacetate) treated with an aqueous alkali solution, having a refractive index of 1.6.
The lens substrate 3 of type 0 is referred to as type 3. The lens under test (5) employs this type 3 lens substrate 3.

(F-1-1-4) Type 4 of lens substrate 3 1,3-bis (isocyanatomethyl) cyclohexane, pentaerythritol tetrakismercaptoacetate, and 2,5-mercaptomethyl 1,4-dithiane The lens substrate 3 having a refractive index of 1.60 is referred to as Type 4. The lens under test (6) employs this type 4 lens substrate 3.

(F-1-2) Types of Hard Coat Film 4 As described above, various types of polysiloxane can be used as the hard coat film 4. The plastic lens 1 having the hard coat film 4 formed from the hard coat liquid was used as a marking target in the marking application experiment. The lens under test (1) has no hard coat film 4.

(F-1-2-1) Type 1 of Hard Coat Film 4 As a silicon compound, 80 mol% of colloidal silica and 2
The hard coat film 4 formed from a coating solution containing 0 mol% of γ-glycidoxypropyltrimethoxysilane is referred to as Type 1. Test lens (2)
(4) has the type 1 hard coat film 4.

(F-1-2-2) Type 2 of Hard Coat Film 4 54 parts by weight of a 0.06 N hydrochloric acid aqueous solution was added dropwise to 212 parts by weight of γ-glycidoxypropyltrimethoxysilane while stirring, and the mixture was added dropwise. After completion, the mixture was stirred for 24 hours to obtain a hydrolyzate. Then, antimony pentoxide sol (methanol-dispersed sol, average particle diameter 10 nm, solid content 30%) 4
24 parts by weight and Denacol EX- as an epoxy compound
521 (manufactured by Nagase Kasei Co., Ltd., 34 parts by weight of polyglycerol polyglycidyl ether) and, after stirring for 5 hours, add 6.8 parts by weight of dibutyltin laurate as a curing catalyst and ripen for another 100 hours. Thus, a coating liquid was obtained. The hard coat film 4 formed from this coating liquid is referred to as type 2. The lens under test (5) has this type 2 hard coat film 4.

(F-1-2-3) Type 3 Hard Coat Film 4 142 parts by weight of γ-glycidoxypropylmethoxysilane was added to a glass container equipped with a magnetic stirrer, and stirred while stirring. 1.4 parts by weight of 0.01N hydrochloric acid and 32 parts by weight of water were added dropwise, and after completion of the addition, the mixture was stirred for 24 hours to obtain a hydrolyzate of γ-glycidoxypropyltrimethoxysilane. Next, a stannic oxide-zirconium oxide composite sol (methanol dispersion, total metal oxide 3
1.5% by weight, average particle size 10 to 15 micron) 4
60 parts by weight, 300 parts by weight of ethyl cellosolve, 0.7 parts by weight of a silicone-based surfactant as a lubricant, and 8 parts by weight of aluminum acetylacetonate as a curing agent were mixed with the above-mentioned γ-glycidoxypropyltrimethoxysilane. After being added to the decomposed product and sufficiently stirred, the solution was filtered to prepare a coating solution. The hard coat film 4 formed from this coating liquid is referred to as type 3. The lens under test (6) has this type 3 hard coat film 4.

(F-1-3) Type of Anti-Reflection Film 5 As described above, various types of anti-reflection films 5 can be applied, but a plastic lens having a type 1 or type 2 anti-reflection film 5 can be used. 1 was set as a marking target in the marking application experiment. The lens under test (4) does not have the antireflection film 5.

(F-1-3-1) Type 1 of Antireflection Film 5 A plastic lens having the hard coat film 4 (the lens under test (1) is composed only of the lens substrate) is put into a vapor deposition machine and evacuated. While heating to 85 ° C., 2 × 10 ⁻⁵ Torr
After evacuation, a deposition material is deposited by an electron beam heating method to form a 0.6 λ thick underlayer made of SiO ₂ , and Ta ₂ O ₅ , ZrO ₂ , and Y ₂ O ₃ are formed on this underlayer. Layer (refractive index 2.05, film thickness 0.075λ) and SiO
_A first refractive index layer composed of _two layers (refractive index 1.46, film thickness 0.056λ), and a mixed layer composed of Ta ₂ O ₅ , ZrO ₂ , and Y ₂ O ₃ (refractive index 2.05, film thickness 0) .46λ) and SiO
_{A two-} layer second refractive index layer was formed to form an anti-reflection film 5 (Japanese Patent Application Laid-Open No. 2-262104). The lenses under test (3), (5) and (6) have this type 1 antireflection film 5.

(F-1-3-2) Type 2 of Antireflection Film 5 A plastic lens having the hard coat film 4 (the lens under test (1) is composed only of the lens substrate) is washed, and the surface thereof is At a pressure of 5 × 10 −5 Torr or less, SiO ₂ is vacuum-deposited to a thickness of 1.5 μm, ZrO ₂ is deposited thereon at about λ / 17, SiO ₂ is deposited thereon, and the total of these two substances is added. Vapor deposition is performed until the film thickness becomes about λ / 4. Then, after ZrO ₂ is deposited thereon by λ / 2, S
iO ₂ is deposited to a thickness of λ / 4 to prevent reflection.
Was formed (JP-A-56-116003). The lenses under test (1) and (2) have this type 2 antireflection film 5.

(F-2) Experimental Setting Conditions The wavelength of the laser light L, the distance from the focal position adjusting lens 2 to the focal point P, and the like are as described above. Further, the line width of the mark M is set to 0.20 to 0.40 mm, and the line depth is set to 0.15 to 0.20 μm.
In the experiment, the combination (irradiation conditions) of the drive voltage of the laser oscillation unit 11 and the number of shots was changed as shown in the table of FIG.
I'm changing it.

(F-3) Marking Judgment Criteria The marking is visually observed by a skilled lens inspector. The appearance of the surface of the plastic lens 1 is inspected for scratches, cracks and coloring. In addition, under normal illumination of a fluorescent lamp, the plastic lens 1 is tilted to appropriately change the viewpoint position of the reflected light, and a mark is detected from the reflected light on the surface of the plastic lens 1. It is best if the mark can be read and there is no glare due to the reflected light from the mark in part or whole (the width and depth of the entire mark are regarded as uniform).

(F-4) Experimental Results The table in FIG. 8 described above also shows the experimental results. The following can be seen from FIG.

When the energy of the laser beam emitted from the laser oscillation section 11 is too small or too large, a good mark cannot be obtained, and it can be seen that there is an energy range of the laser beam from which a good mark can be obtained.

On the lower end of the energy range, a good mark cannot be obtained unless the number of shots is large. Conversely, on the upper end of the energy range,
It can be seen that good marks cannot be obtained unless the number of shots is small.

Further, the lens substrate 3 and the hard coat film 4
Regardless of the combination of the antireflection film 5 and the combination of the antireflection films 5, it can be seen that almost the same results were obtained for all the lenses under test (1) to (6). That is, it can be assumed that similar results are obtained for various types of plastic lenses 1.

(G) Effects of the Embodiment According to the above embodiment, the following effects can be obtained.

[0087]

When the focal point of the laser beam is selected on the surface of the lens substrate 3, the lens substrate 3 and the surface treatment films 4, 5
Depending on the material, the surface treatment films 4 and 5 may be easily damaged or cracked. However, when the material is selected as in the above-described embodiment, the mark is applied without causing such scratches or cracks. can do.

Further, in the case where a marking-applied portion is selected inside the lens substrate 3, it is difficult to adjust the depth and size of the formed mark, and it is difficult to make the quality of the formed mark constant. In the case where the vicinity of the surface of the lens substrate 3 is selected as a marking application point as in this embodiment, there is no adjustment in the optical axis direction of the convergence point of the laser beam. Is easy to adjust, the depth and size of the mark can be arbitrarily selected, and the mark quality can be kept constant.

Further, in the case of this embodiment, without moving the plastic lens 1 or the optical system, the mask 1
Since the mark figure is formed by the laser beam that has passed through 4, the marking time per plastic lens 1 can be made shorter than before. In addition, as described above, when the vicinity of the surface of the lens substrate 3 is selected as the marking application portion, there is no adjustment in the optical axis direction of the convergence point of the laser beam. Since the diameter can be easily adjusted, it is possible to form a mark figure using the laser light that has passed through the mask section 14.

Further, by changing the mask section 14, it is possible to easily cope with a change in the mark figure. For example, when the mask unit 14 is configured by arranging a plurality of stencils on a rotatable circular holder in the circumferential direction, it is possible to further easily change the mark figure, and to control the rotation of such a mask unit 14. Is performed by the host computer, the mark figure can be changed in a short time.

By the way, although not mentioned in the section of the prior art, there is a method using ink as a marking method. In comparison with this, the method of the embodiment has an effect of not polluting the working environment. There is also a marking method of giving a mark that can be recognized in response to ultraviolet rays. However, in comparison with this, the embodiment has an effect that a special device is not required for the recognition of the mark.

(H) Other Embodiments In the above embodiments, the marking target is a plastic lens, but the present invention is not limited to this, and other optical components whose base material is plastic It can also be applied to

Various effects can be obtained by using the mask portion 14 for marking, but by moving the marking object or the optical system in the direction perpendicular to the optical axis without using the mask portion 14. Alternatively, the focus point near the surface of the plastic lens 1 may be moved to form a mark figure.

[0095]

As described above, according to the present invention, a mark is provided by focusing a laser beam near the surface of a plastic optical component having a polysiloxane-based hard coat film and / or an antireflection film. Therefore, it is possible to realize a laser marking method that can easily adjust a laser beam and can easily apply a desired mark.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a laser marking method according to an embodiment.

FIG. 2 is a block diagram illustrating a configuration for realizing a laser marking method according to an embodiment.

FIG. 3 is a plan view showing a mask section of the embodiment.

FIG. 4 is a plan view showing a lens convex surface fixing positioning plate according to the embodiment.

FIG. 5 is a plan view showing a marking target after a mark is applied.

FIG. 6 is an explanatory diagram showing a surface unevenness state of a marking target marked according to an example.

FIG. 7 is a table showing a configuration of a target lens of a marking imparting experiment to which the method of the embodiment is applied.

FIG. 8 is a table showing laser beam irradiation conditions and experimental results of a marking application experiment to which the method of the embodiment is applied.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Plastic lens (marking target), 2 ... Lens for focusing position, 3 ... Lens base material, 4 ... Hard coat film, 5 ... Anti-reflection film, 10 ... Laser irradiation device, 14
... Mask part (stencil), 20 ... Lens holding device, L
... Laser light, M ... Mark, P ... Convergence point of laser light.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-124486 (JP, A) JP-A-1-214480 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/26

Claims (4)

(57) [Claims] 1. A laser marking method in which a laser beam is focused on a marking object to be provided with a mark and the mark is applied to the marking object, wherein the marking object is a polysiloxane-based hard coat film and / or a reflection material. a surface-treated plastic optical parts preventing film, dividing the interior the plastic optical component
Surface of the optical component so that the laser light converges near the surface.
A laser marking method comprising irradiating a surface with a laser beam to give a mark. 2. A laser light applied to the plastic optical component has passed through a mask portion including a light shielding portion and an optical window portion having the same shape as a mark figure. The laser marking method described in 1. 3. A laser marking method in which a laser beam is focused on a marking object to be provided with a mark and the mark is applied to the marking object, wherein a polysiloxane-based hard coat film and an antireflection film are formed on the surface of the lens substrate. Lens base of formed plastic lens
CO2 laser light converges near the surface except inside the material
The substrate surface is irradiated with carbon dioxide laser light as
A laser marking method, wherein a mark is provided such that a convex portion is formed on the surface of a stick lens. 4. The method according to claim 1, wherein the mark is a hidden mark.
The laser beam according to any one of claims 1 to 3, wherein
Working method.