JP5233565B2 - Marking formation method for optical glass member and optical glass member with marking - Google Patents

Description

  The present invention relates to a marking forming method for an optical glass member and an optical glass member with marking.

  For the purpose of product management and design, marking may be applied on the glass member. As a method for forming the marking, direct marking using a scanning laser is widely used. Here, direct marking means a method of marking a member by marking the surface of the member to be marked with a laser beam and performing laser ablation.

Other marking forming methods include, for example, laser scanning on a glass surface coated and coated with a colored paste kneaded in the paste using metal powder and / or inorganic pigment as a coloring source, thereby curing the paste in the laser scanning section. After the colored paste pattern is formed, the uncured colored paste excluding the laser scanning portion is dissolved in an organic solvent and then removed and baked, whereby the drawing pattern formed by baking the colored paste pattern is made of glass. A method of forming on the surface (see Patent Document 1) is disclosed.
JP 2004-351746 A

  An object of the present invention is to provide a marking forming method on an optical glass member in which the influence on the optical performance of the optical glass member is reduced to a practically sufficient level. Another object of the present invention is to provide an optical glass member with marking in which marking is formed by the marking forming method.

  The present invention provides a light-transmitting fine particle having an absorption of 0.1% / cm or more (wavelength of light) at a wavelength at which the internal transmittance of the optical glass member is 99.9% / cm or more. Measuring the internal transmittance of the optical glass member, and selecting a wavelength exhibiting an internal transmittance of 99.9% / cm or more, and transmitting light having an absorption of 0.1% / cm or more at the selected wavelength A film of a dispersion in which the fine particles are dispersed in a medium, and the marking-forming region on the surface on which the film is formed is irradiated with the laser beam having the above-described wavelength, so that the translucent fine particles are applied to the optical glass member. A method for forming a marking on an optical glass member to be fused is provided.

  As the light-transmitting fine particles, those having a melting point of 2000 ° C. or less are preferable, and the light-transmitting fine particles are preferably made of a crystal containing a metal oxide or an amorphous material containing silicon. As the crystal containing a metal oxide, a crystal containing bismuth oxide or molybdenum oxide is suitable.

A medium containing a water-soluble polymer and water can be used as the medium. In addition, the wavelength of the laser light applied to the surface on which the film is formed is preferably the fundamental wavelength, the double wavelength, or the triple wavelength of the YAG laser or YVO ₄ laser.

  If the above-mentioned marking formation method is applied, the optical glass member with a marking in which the marking was formed on the optical glass member can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the marking formation method on the optical glass member and the optical glass member with a marking by which the influence on the optical performance of an optical glass member was reduced to practically sufficient level are provided.

  In the following, preferred embodiments of the present invention will be described with reference to the drawings as the case may be. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and duplicate descriptions are omitted.

  Drawing 1 is a sectional view explaining the marking formation method of the optical glass member concerning an embodiment. In order to implement the marking forming method of the present embodiment, first, a lens-shaped optical glass member 1 is prepared as an optical glass member that exhibits optical performance. Next, a dispersion (coating material) obtained by dispersing translucent fine particles in a medium composed of a water-soluble polymer and water is applied on the prepared optical glass member 1 to remove volatile components, and a film is formed. 15 is formed. Then, the formed film 15 is irradiated with laser light 9 generated from the laser device 8 to heat the film 15 in the marking formation region (region where the marking is to be formed) on the surface on which the film 15 is formed. The translucent fine particles contained in the film 15 are fused (melted and fixed) to the optical glass member 1.

  The optical glass member marking forming method is carried out as described above. However, each of the light-transmitting fine particles may be fused to the optical glass member 1 by the irradiation of the laser light 9, or the light-transmitting fine particles are melted. It may be fused to the optical glass member 1 while being worn. The wavelength of the laser light 9 is a wavelength at which the internal transmittance of the optical glass member 1 is 99.9% / cm or more. At this wavelength, the light-transmitting fine particles absorb 0.1% / cm or more. Have.

  It is preferable to wash (wash with water) the optical glass member 1 after fusing. By cleaning, only the fused portion (that is, the marking formation region) of the film 15 remains on the optical glass member 1. In this embodiment, since water in which a water-soluble polymer is dissolved is used as a medium, the film in the portion not irradiated with the laser light 9 can be easily removed by washing (washing). On the other hand, the water-soluble polymer is burned and removed by the generated heat in the portion irradiated with the laser beam 9, and even when it is not completely removed, it is removed during washing (water washing).

  FIG. 2 is a cross-sectional view of an optical glass member with marking obtained by such a marking forming method. An optical glass member with marking 100 shown in FIG. 2 includes an optical glass member 1 and a marking 10 (a fusion product of translucent fine particles) formed thereon. Examples of the shape of the marking 10 include a barcode shape and a character shape.

  The translucent fine particles can be produced, for example, by pulverizing a translucent material. The average particle diameter of the translucent fine particles is usually 0.1 to 10 μm, but from the viewpoint of making the marking inconspicuous by suppressing surface scattering by the formed marking, it is 0.1 to 0.5 μm. It is preferable.

  As the light-transmitting fine particles, those having an absorption of 0.1% / cm or more at a wavelength at which the internal transmittance of the optical glass member is 99.9% / cm or more are used. Examples of such translucent fine particles include those made of crystals containing metal oxides and amorphous materials containing silicon.

Examples of the laser light 9 used for fusing the coating 15 include a YAG laser, a YVO ₄ laser, and a CO ₂ laser. The wavelength of the laser light 9 applied to the film 15 is such that the internal transmittance of the optical glass member 1 is 99.9% / cm or more (preferably 99.95% or more, and further 99.99% or more). To do. When laser light having a wavelength with an internal transmittance of the optical glass member 1 of less than 99.9% / cm is irradiated, there may be a problem that the optical glass member 1 is cracked. Examples of the wavelength of the laser light 9 applied to the film 15 include the fundamental wavelength (1060 nm), second harmonic (530 nm), and third harmonic (353 nm) of the YVO ₄ laser described above.

  At a wavelength at which the internal transmittance of the optical glass member is 99.9% / cm or more, the light-transmitting fine particles having an absorption of 0.1% / cm or more cause absorption at the laser wavelength described above. Therefore, when the laser beam having the above-described wavelength is irradiated onto the coating 15 containing the light-transmitting fine particles, the light-transmitting fine particles absorb the laser light and generate heat. The translucent fine particles are melted by generating heat and are fixed to the surface of the optical glass member 1. On the other hand, since the laser beam is hardly absorbed by the optical glass member 1, it is possible to form a marking having a desired shape on the optical glass member 1 while preventing generation of cracks in the optical glass member.

  Examples of the type of marking include a marking that can be easily recognized with the naked eye in visible light and a marking that can be easily recognized with the naked eye in visible light by a specific means.

  When forming a marking that can be easily recognized with the naked eye in visible light, it is preferable to use a light-transmitting fine particle made of a crystal containing a metal oxide. Such translucent fine particles generally have a refractive index difference of 0.1 or more with respect to the optical glass member. Therefore, the marking formed using such translucent fine particles can be recognized with the naked eye in visible light.

  Examples of the metal oxide include bismuth oxide, molybdenum oxide, aluminum oxide, magnesium oxide, titanium oxide, zirconium oxide, hafnium oxide, tin oxide, indium oxide, lead oxide, and zinc oxide.

  Moreover, it is preferable that the crystal containing a metal oxide has a melting point of 2000 ° C. or lower. When the crystal having such a melting point is used, the coating 15 can be easily fixed on the optical glass member 1 and a marking which is difficult to peel off can be formed. From such a viewpoint, the melting point of the crystal containing the metal oxide is more preferably 1000 ° C. or lower.

  Examples of the metal oxide having a melting point of 1000 ° C. or less include bismuth oxide, molybdenum oxide, lead oxide, and the like.

  In addition, when bismuth oxide is used as the metal oxide, the marking can be easily removed with an acid such as hydrochloric acid or sulfuric acid even when the marking is not necessary in a later process. Bismuth oxide is soluble in acid, for example, dissolved in hydrochloric acid having a concentration of 10 wt% at a rate of about 1 μm / min. Therefore, when the optical glass member is acid-resistant, the marking is removed from the optical glass member without causing a decrease in the optical performance of the optical glass member by applying an acid on the formed marking. Is possible.

  In the case of forming a marking that can be easily recognized with the naked eye in visible light by a specific means, it is preferable to use a material made of an amorphous material containing silicon as the light-transmitting fine particles. Such translucent fine particles usually have a refractive index difference of 0.1 or less with respect to the optical glass member. Therefore, it is difficult to recognize the marking formed using such translucent fine particles even if the marking is seen in the optical axis direction of the optical glass member, but it is recognized if observed from a direction at a predetermined angle from the optical axis. Is possible. In addition, the light can be recognized by irradiating light from a condenser lamp from a direction that makes a predetermined angle from the optical axis and observing from the direction of the optical axis.

  Examples of the amorphous substance containing silicon include borosilicate glass, lanthanum borate glass, and fluoride phosphate glass. From the viewpoint of suppressing surface scattering due to the formed marking and making the marking inconspicuous, it is preferable to use an optical glass with few optical defects such as bubbles and striae as an amorphous material containing silicon. Note that the amorphous body containing silicon preferably has a melting point of 1000 ° C. or lower.

  When the absorption of the amorphous material containing silicon with respect to the wavelength at which the internal transmittance of the optical glass member is 99.9% / cm or more is less than 0.1% / cm, the absorption is 0.1% / You may add a coloring agent so that it may become cm or more. Examples of the colorant include iron, cobalt, nickel, chromium, manganese, vanadium, selenium, copper, gold, silver, sulfur, titanium, and neodymium.

  In addition, it is preferable that the amorphous body containing silicon and the optical glass member 1 have close compositions and glass transition temperatures. Materials whose composition and glass transition temperature are close to each other are likely to stick to each other.

  As the medium for dispersing the translucent fine particles, a medium that can be washed away by washing is preferable. Any cleaning method may be selected as long as the translucent fine particles and the optical glass member are not deteriorated. For example, the cleaning method may be appropriately selected depending on the mechanical strength of the optical member. Examples of the cleaning method include ultrasonic cleaning, immersion cleaning, and jet cleaning.

  Examples of the medium include water; alcohols such as methanol and ethanol. From the viewpoint of moldability such as control of the coating thickness of the coating layer, the medium preferably contains a binder polymer and a solvent capable of dissolving, swelling or dispersing the binder polymer. Examples of the binder polymer include polyvinyl alcohol (PVA) and polyvinylidene fluoride (PVDF), and examples of the solvent include water; alcohols such as methanol and ethanol.

  From the viewpoint of simplifying the process, it is preferable that the medium can be washed with water. From such a viewpoint, it is preferable that the binder polymer is a water-soluble polymer and the solvent is water. Examples of the water-soluble polymer include starch, gelatin, cellulose derivatives (carboxymethyl cellulose, methyl cellulose, etc.), polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyethylene oxide, and the like. Since a thing is obtained, polyvinyl alcohol (PVA) is preferable. In addition, since PVA is normally decomposed | disassembled and volatilized at 700 degreeC or more, it does not remain as a residue after laser scanning. This is also suitable for use as a binder polymer.

  The content of the binder polymer is preferably 1 to 10% by weight, more preferably 1 to 5% by weight, based on the total weight of the dispersion in which the translucent fine particles are dispersed in the medium.

  Although there is no restriction | limiting in particular in the application | coating on the optical glass member 1 of a dispersion, For example, spraying with an airbrush, application | coating using a brush, a stamp, etc., dip coating, spin coating are mentioned. Moreover, it is preferable to apply | coat so that the thickness after drying, ie, the thickness of the membrane | film | coat 15, may be 5-50 micrometers. The thickness of the film 15 is particularly preferably 5 to 20 μm. If the thickness of the film 15 is larger than 50 μm, it tends to be difficult to print with a laser, and if it is smaller than 5 μm, the marking tends to be difficult to read.

  According to the marking forming method as described above, the marking 10 having a small influence on the optical performance of the optical glass member can be formed on the optical glass member 1. The optical glass member with marking formed in this way has few cracks, deformation of the shape of the optically effective portion, and the like, and the deterioration of the optical performance is sufficiently suppressed.

In addition, when marking by direct marking, the following problems have occurred. Since the optical glass member is usually a brittle material, there is a problem that if the absorption at the wavelength of the laser is increased, cracks are generated and the optical performance of the optical glass member is lowered. On the other hand, if the absorption at the wavelength of the laser is reduced in order to suppress the generation of cracks, ablation itself has become difficult. Specifically, when direct marking is applied to an optical glass member using the fundamental wavelength (1060 nm) and second harmonic (530 nm) of a YAG laser or YVO ₄ laser, ablation of the optical glass member itself is difficult. . At the third harmonic (353 nm), ablation is possible, but cracks are inevitable. If an infrared carbon dioxide laser that is the absorption wavelength range of glass is used, ablation is possible, but since the wavelength is as long as about 10.6 μm, it is difficult to make a fine marking of mm size or less.

  Further, as a marking forming method other than the above-described method, for example, a method of drawing a laser beam by condensing a laser beam inside the transparent member is known. When marking is given to a member, distortion will generate | occur | produce inside an optical glass member, and optical performance will fall.

  Further, in the conventional method in which laser scanning is performed, sufficient adhesion cannot be obtained only by curing by laser scanning, and after pattern formation by laser scanning, it is necessary to heat and bake at a high temperature of 750 ° C. in an electric furnace or the like. However, such a high firing temperature causes the precise shape of the optically effective portion of the optical glass member to be deformed and causes the optical performance of the optical glass member to deteriorate.

  However, according to the marking forming method of the present invention, such a problem can be avoided.

  In this embodiment, the example using the lens-shaped member (optical lens) was shown as the optical glass member 1, However, As long as the effect of this embodiment is exhibited, any optical glass member can be used. Examples of such optical glass members include prisms, mirrors, optical filters, beam splitters, and polarizing elements.

  Next, a method for reading the marking formed in the present embodiment will be described.

  FIG. 3 is a diagram for explaining a preferred example of the marking reading method. The optical member 100 used in the marking reading method includes an optical glass member 1 and a marking 10 formed on the optical glass member 1. Here, the surface on which the marking 10 is formed in the optical member 100 is referred to as an upper surface, and the direction facing the upper surface is referred to as a lower surface.

  When reading the marking, for example, the visible light 5 is irradiated obliquely from the upper surface side of the optical member 100 toward the marking 10, and the marking 10 is viewed from the side irradiated with the visible light 5 (upper surface side of the optical member 100). Thus, the marking can be read out. For irradiation with the visible light 5, for example, a condenser lamp can be used.

  As described above, the preferable example of the marking forming method and the reading method of the marking according to the present embodiment has been described. However, the present invention is not limited to this.

Example 1
(Production of coating material)
As translucent fine particles, bismuth oxide powder having an average particle size of about 1 μm was prepared. The melting point of bismuth oxide is about 800 ° C. Then, 5 g of pure water and 10 g of a polyvinyl alcohol 10 wt% aqueous solution (manufactured by Wako Pure Chemical Industries) were mixed with 1 g of the prepared bismuth oxide powder to prepare a coating material (glass paste).

(Formation of markings on optical glass members)
As an optical glass member, an optical lens formed from BK7 manufactured by Schott Corp., which is borosilicate glass, was prepared. And the coating material produced as mentioned above was sprayed on the optical lens using the airbrush, and the coating material layer about 10 micrometers thick was formed.

Thereafter, the coating material layer was dried to form the coating layer, and then the glass was melted and fixed on the surface of the optical member using a scanning laser as shown in FIG. The laser used was a laser marker using a second harmonic of YVO ₄ laser (Miyachi Technos, ML-9001A, wavelength 532 nm) as a light source. Such a laser can print small characters and barcodes of 1 mm or less. The laser irradiation conditions were a current of 23 A, a frequency of 20 kHz, and a scanning speed of 100 mm / s. At this wavelength, the internal transmittance of the optical glass member (optical lens) was 99.9% / cm or more, and the absorption of the bismuth oxide powder was 10% / cm or more.

  The coating layer containing bismuth oxide was melted by being heated to about 800 ° C., which is the melting point of bismuth oxide, by laser irradiation, and baked onto the surface of the optical glass. In addition, since polyvinyl alcohol (PVA) decomposes | dissolves and volatilizes at 700 degreeC or more, it seems that it does not exist after laser scanning.

  Then, in order to form a pattern, ultrasonic cleaning was performed with pure water in order to clean and remove the excess coating layer that was not baked. After washing, the optical member was dried. As described above, the marking was formed on the laser scanning portion on the optical lens. Moreover, there was almost no deterioration in the optical performance of the optical glass member due to the formation of the marking.

(Reading of marking)
Using a condenser lamp, 10000 lumen white light was irradiated from the upper surface side of the produced optical member, and the marking was observed by the method shown in FIG. As a result, the characters were clearly visible.

(Removal of marking)
When hydrochloric acid having a concentration of 10 wt% was applied onto the marking, all the bismuth oxide baked after 2 minutes had dissolved. Since BK7 manufactured by Schott was insoluble in hydrochloric acid, the optical performance of the optical glass member was not deteriorated due to the removal of the marking.

(Example 2)
A marking was formed by the same method as in Example 1 except that zinc oxide powder was used as the light-transmitting fine particles. The melting point of zinc oxide is about 1980 ° C. Moreover, the absorption of the zinc oxide powder was 10% / cm or more at the irradiated laser wavelength.

  Also in this example, there was almost no deterioration in the optical performance of the optical glass member due to the formation of the marking. However, compared with Example 1, the image sticking state was poor, for example, the adhesion strength of the marking to the optical glass member was insufficient.

(Example 3)
A marking was formed by the same method as in Example 1 except that molybdenum oxide powder was used as the light-transmitting fine particles. The melting point of molybdenum oxide is about 800 ° C. In addition, at the irradiated laser wavelength, the absorption of the molybdenum oxide powder was 10% / cm or more.

  Also in this example, there was almost no deterioration in the optical performance of the optical glass member due to the formation of the marking. Further, the burn-in state of the marking on the optical glass member was almost the same as that in Example 1.

Example 4
Example 1 except that tellurite glass containing 10 mol% or more of TeO ₂ was used as the light-transmitting fine particles, and that the laser wavelength was the fundamental wave of YVO ₄ laser (manufactured by Miyachi Technos, wavelength 1064 nm) A marking was formed by the same method. The absorption of the tellurite glass at the irradiated laser wavelength was 0.2% / cm.

  Also in this example, there was almost no deterioration in the optical performance of the optical glass member due to the formation of the marking. Further, the burn-in state of the marking on the optical glass member was almost the same as that in Example 1.

(Reading of marking)
Using a condenser lamp, 10000 lumen white light was irradiated from the upper surface side of the produced optical member, and the marking was observed by the method shown in FIG. As a result, the characters were clearly visible.

(Example 5)
The pulverized HOYA LAF2 glass was mixed with neodymium oxide. The addition amount of neodymium oxide was 0.5 mol% with respect to the total amount of LAF2 glass and neodymium oxide. The obtained mixture was melted to produce glass, and the produced glass was further pulverized to form translucent fine particles.

  A marking was formed by the same method as in Example 1 except that such glass was used as the light-transmitting fine particles. Further, the absorption of the light-transmitting fine particles was 0.5% / cm at the irradiated laser wavelength.

  Under such conditions, the light-transmitting fine particles have sufficiently absorbed the laser wavelength, and the temperature rose to the melting point or more by laser irradiation. Thereby, the coating layer was melted and fixed satisfactorily.

  Also in this example, there was almost no deterioration in the optical performance of the optical glass member due to the formation of the marking.

(Reading of marking)
Using a condenser lamp, 10000 lumen white light was irradiated from the upper surface side of the produced optical member, and the marking was observed by the method shown in FIG. As a result, the characters were clearly visible.

(Comparative Example 1)
To the ground HOYA Co. LAF2 glass was translucent fine particles, the laser wavelength, YVO ₄ laser fundamental wave (Miyachi Technos Co., ML-7111A, wavelength 1064 nm) except that the A, as in Example 1 The marking was formed by the method described above. Here, at the irradiated laser wavelength, the absorption of the translucent fine particles was less than 0.1% / cm.

  Under such conditions, the coating layer could not be melted and fixed, and the marking itself could not be formed. This is probably because the light-transmitting fine particles did not absorb the laser wavelength sufficiently, and the temperature did not rise above the melting point even by laser irradiation.

It is sectional drawing explaining the suitable marking formation method in this embodiment. It is sectional drawing of the optical glass member with a marking. It is a figure for demonstrating a suitable example of the marking reading method.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Optical glass member, 8 ... Laser apparatus, 9 ... Laser beam, 10 ... Marking, 15 ... Film | membrane, 100 ... Optical glass member with marking

Claims (4)

On the optical glass member,
Forming a film of a dispersion in which translucent fine particles having absorption of 0.1% / cm or more at a wavelength at which the internal transmittance of the optical glass member is 99.9% / cm or more are dispersed in a medium;
It is a marking forming method for an optical glass member, wherein the marking forming region of the surface on which the film is formed is irradiated with laser light of the wavelength to fuse the translucent fine particles to the optical glass member ,
The translucent fine particles have a melting point of 2000 ° C. or less and are made of crystals containing a metal oxide,
A marking forming method, wherein the crystal contains bismuth oxide or molybdenum oxide . The marking forming method according to claim 1, wherein the medium contains a water-soluble polymer and water. The wavelength is, the fundamental wavelength of the YAG laser or a YVO ₄ laser, a wavelength twice or 3 times the wavelength, the marking formation process according to claim 1 or 2. The optical glass member with a marking in which the marking was formed by the marking formation method as described in any one of Claims 1-3 .