Method for producing marked product

Abstract

To provide a method for producing a marked product, which is increased in machining speed.SOLUTION: This method for producing the marked product comprises: conveying an object on a conveyance path; disposing a beam forming mechanism for forming a regular intensity distribution of laser beams by splitting the laser beams generated from a laser oscillator in accordance with a prescribed pattern or blocking some of the laser beams in accordance with a prescribed pattern between the laser oscillator and the conveyance path; disposing a mask member in which a transmission pattern corresponding to a design of a mark added to the object is formed between the laser oscillator and the conveyance path; generating laser beams from the laser oscillator; and irradiating the currently conveyed object with the laser beams passed through the beam forming mechanism and the mask member. The advancing directions of the laser beams emitted from the beam forming mechanism is one direction which is similar to the advancing direction entering the beam forming mechanism.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing marked products. [Background technology]

[0002] Patent Document 1 discloses a laser marking device. The laser marking device in Patent Document 1 uses the same scanning means and lens to scan and process the surface of an object with multiple lasers. The scanning means has a first scanning means that scans in a first direction and a second scanning means that scans in a direction approximately perpendicular to the first direction, and the first scanning means is located in the optical path where the optical paths of the multiple lasers converge. The object is controlled to move in the same direction as one of the scanning means. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-025326 Summary of the Invention [Problem to be solved by the invention]

[0004] In the laser marking device of Patent Document 1, an object whose movement is controlled in one direction is divided into multiple regions for marking, and multiple laser light sources are assigned to these regions. According to Patent Document 1, productivity is improved by reducing the marking area per beam in this way. However, in a method of forming dots on an object surface while scanning the laser light, it is necessary to reduce the object's movement speed in accordance with the dot marking speed. For this reason, further improvement in the processing speed of laser marking is desired.

[0005] The present disclosure aims to provide a method for producing marked products with improved processing speed. [Means for solving the problem]

[0006] A method for producing a marked product according to a first aspect of the present disclosure includes transporting an object along a transport path, disposing a beam shaping mechanism between a laser oscillator and the transport path that branches laser light generated from the laser oscillator according to a predetermined pattern or blocks part of the laser light according to a predetermined pattern, thereby forming a regular intensity distribution of the laser light, disposing a mask member between the laser oscillator and the transport path on which a design pattern that transmits or blocks the laser light is formed corresponding to the design of the marking to be made on the object, and generating laser light from the laser oscillator and irradiating the object being transported with the laser light that has passed through the beam shaping mechanism and the mask member. The traveling direction of the laser light emitted from the beam shaping mechanism is unidirectional, which is the same as the traveling direction of the laser light incident on the beam shaping mechanism.

[0007] A method for producing a marked product according to a second aspect of the present disclosure is a method for producing a marked product according to the first aspect, in which the laser oscillator is an excimer laser oscillator, a UV laser oscillator, a CO2 laser oscillator, or a YAG laser oscillator.

[0008] A method for producing a marked product according to a third aspect of the present disclosure is a method for producing a marked product according to the first or second aspect, wherein the beam shaping mechanism is an optical element made of a material that transmits laser light and has a regular pattern consisting of flat portions that transmit laser light and curved portions adjacent to the flat portions that branch the laser light to the adjacent flat portions.

[0009] A method for producing a marked product according to a fourth aspect of the present disclosure is a method for producing a marked product according to any one of the first to third aspects, wherein the beam shaping mechanism is a photomask having a regular pattern consisting of blocking areas that block laser light and transparent areas that transmit laser light.

[0010] A method for producing a marked product according to a fifth aspect of the present disclosure is a method for producing a marked product according to any one of the first to fourth aspects, wherein the beam shaping mechanism is a member having a regular pattern formed thereon, the pattern consisting of a shielding area that blocks the laser light and a transparent area that transmits the laser light, and the shielding area is formed by a highly reflective mirror.

[0011] A method for producing a marked product according to a sixth aspect of the present disclosure is a method for producing a marked product according to any one of the first to fifth aspects, wherein the mask member is a photomask on which the design pattern is formed, the photomask comprising a shielding area that blocks the laser light and a transparent area that transmits the laser light.

[0012] A method for producing a marked product according to a seventh aspect of the present disclosure is a method for producing a marked product according to any one of the first to sixth aspects, wherein the mask member is a member on which the design pattern is formed, the mask member consisting of a shielding area that blocks the laser light and a transparent area that transmits the laser light, and the shielding area is formed by a highly reflective mirror.

[0013] A method for producing a marked product according to an eighth aspect of the present disclosure is a method for producing a marked product according to any one of the first to seventh aspects, in which the beam shaping mechanism and the mask member are integrally configured.

[0014] A method for producing a marked product according to a ninth aspect of the present disclosure is a method for producing a marked product according to any one of the first to eighth aspects, wherein the object comprises a resin container body including a bottom portion, a side portion extending upward from the outer peripheral edge of the bottom portion, a mouth portion defining an upper opening, and a shoulder portion continuous with the side portion and the mouth portion, and a recessed portion is formed in at least one of the bottom portion, side portion, and shoulder portion, and irradiating the object being transported with laser light that has passed through the beam shaping mechanism and the mask member includes irradiating the laser light onto the inner surface of the recessed portion.

[0015] A method for producing a marked product according to a tenth aspect of the present disclosure is the method for producing a marked product according to any one of the first to ninth aspects, wherein the recessed portion is formed in the side surface portion.

[0016] A method for producing a marked product according to an eleventh aspect of the present disclosure is a method for producing a marked product according to any one of the first to tenth aspects, wherein the recessed portion extends around the entire periphery of the side portion.

[0017] A method for producing a marked product according to a twelfth aspect of the present disclosure is a method for producing a marked product according to any one of the first to eleventh aspects, wherein the recessed portion extends from the outer peripheral edge of the bottom portion to the upper end of the side portion.

[0018] A method for producing a marked product according to a thirteenth aspect of the present disclosure is a method for producing a marked product according to any one of the first to twelfth aspects, wherein the inner surface of the recessed portion forms a flat surface facing the external space of the container body at the innermost position, and irradiating the laser light onto the inner surface of the recessed portion includes irradiating the laser light onto the flat surface.

[0019] A method for producing a marked product according to a fourteenth aspect of the present disclosure is a method for producing a marked product according to any one of the first to thirteenth aspects, wherein the object comprises a resin container body including a bottom portion, a side portion extending upward from the outer peripheral edge of the bottom portion, a mouth portion defining an upper opening, and a shoulder portion continuous with the side portion and the mouth portion, and at least one of the bottom portion, side portion, and shoulder portion has a protrusion formed thereon that protrudes from the outer surface, and irradiating the object being transported with laser light that has passed through the beam shaping mechanism and the mask member includes irradiating the laser light near the protrusion.

[0020] A marked product according to a fifteenth aspect of the present disclosure comprises a resin container body including a bottom portion, a side portion extending upward from the outer peripheral edge of the bottom portion, a mouth portion defining an upper opening, and a shoulder portion continuous with the side portion and the mouth portion, and at least one of the bottom portion, side portion, and shoulder portion is formed with a marking area including a collection of multiple recesses or a collection of multiple protrusions formed on the outer surface, the marking area displaying a predetermined design, and a recessed portion, and the marking area is formed on the inner surface of the recessed portion.

[0021] A marked product according to a sixteenth aspect of the present disclosure is the marked product according to the fifteenth aspect, wherein the marking area and the recessed portion are formed on the side surface.

[0022] A marked product according to a seventeenth aspect of the present disclosure is the marked product according to the fifteenth or sixteenth aspect, wherein the recessed portion extends around the entire periphery of the side surface portion.

[0023] A marked product according to an eighteenth aspect of the present disclosure is a marked product according to any one of the fifteenth to seventeenth aspects, wherein the recessed portion extends from the outer peripheral edge of the bottom portion to the upper end of the side portion.

[0024] A marked product according to a 19th aspect of the present disclosure comprises a resin container body including a bottom portion, a side portion extending upward from the outer peripheral edge of the bottom portion, a mouth portion defining an upper opening, and a shoulder portion continuous with the side portion and the mouth portion, and at least one of the bottom portion, side portion, and shoulder portion is provided with a marking area including a collection of multiple recesses or multiple protrusions formed on the outer surface, the marking area displaying a predetermined design, and a protrusion protruding outward from the marking area near the marking area. [Effects of the Invention]

[0025] The present disclosure provides a method for producing marked products with increased processing speed. [Brief explanation of the drawings]

[0026] [Figure 1] 1A to 1C are diagrams illustrating a method for producing marked products according to an embodiment. [Figure 2A] FIG. 2 is a diagram showing an example of the configuration of a beam shaping mechanism. [Figure 2B] FIG. 10 is a diagram showing another example of the configuration of the beam shaping mechanism. [Figure 2C] FIG. 10 is a plan view showing yet another configuration example of the beam shaping mechanism. [Figure 3] FIG. 3 is a plan view showing an example of the configuration of a mask member. [Figure 4] 10 is a flowchart showing an example of the flow of a method for producing marked products. [Figure 5] FIG. 1 shows a first example configuration of an object and a marked product. [Figure 6] FIG. 10 shows a second example configuration of an object and a marked product. [Figure 7] FIG. 10 shows a third example configuration of an object and a marked product. [Figure 8] FIG. 10 is a diagram showing a fourth example configuration of an object and a marked product. [Figure 9] FIG. 10 shows a fifth example configuration of an object and a marked product. [Figure 10A] 5A and 5B are diagrams illustrating the behavior of incident laser light in a beam shaping mechanism. [Figure 10B] 10A and 10B are diagrams illustrating the behavior of incident laser light in another beam shaping mechanism. [Figure 10C] 10A and 10B are diagrams illustrating the behavior of incident laser light in yet another beam shaping mechanism. [Figure 11A] FIG. 10 is a diagram showing a photomask pattern according to a modified example. [Figure 11B] FIG. 10 is a diagram showing a photomask pattern according to another modified example. [Figure 11C] FIG. 10 is a diagram showing a photomask pattern according to yet another modified example. [Figure 11D] FIG. 10 is a diagram showing a photomask pattern according to yet another modified example. [Figure 12] FIG. 1 is a diagram showing the configuration of a marking device for carrying out a production method according to an embodiment. [Figure 13] FIG. 10 is a diagram showing the configuration of a marking device for executing a production method according to a comparative example. [Figure 14] Images of the mask material used in the experiment. [Figure 15] Microscope image of the markings created in the experiment. [Figure 16A] 10 is a microscope image of a marking created using a beam shaping mechanism according to an embodiment. [Figure 16B] 10 is a microscope image of a marking created using a beam shaping mechanism according to an embodiment. [Figure 16C] 10 is a microscope image of a marking created using a beam shaping mechanism according to an embodiment. [Figure 16D] 10 is a microscope image of a marking created using a beam shaping mechanism according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, a method for producing a marked product according to an embodiment of the present disclosure will be described with reference to the drawings.

[0028] <1. Overall structure> 1 is a diagram illustrating a method for producing marked products, including a laser marking method (hereinafter also simply referred to as the "marking method") according to one embodiment of the present disclosure. The marking method according to this embodiment reduces the processing time required for each marking, compared to conventional marking methods. Therefore, it can be particularly preferably applied to a conveyance line where multiple objects are continuously conveyed, enabling the efficient production of marked products.

[0029] The object to be marked is not particularly limited, and examples thereof include resin products, metal products, electronic components (e.g., circuit elements sealed with resin), edible products, glass products, ceramic products, wood products, leather products, paper products, textile products, rubber products, and packaging materials (e.g., plastic films). The surface of the object may be made of any material, but preferably has a property that changes color and gloss upon irradiation with laser light to the extent that the marked design becomes visible. However, the object may be pre-colored in the marking area to be marked, and processed so that the visibility of the marked design is enhanced by removing the color, or the area may be colored after marking. Furthermore, the object may be made of a material containing a component that changes color upon irradiation with laser light. A typical example of a resin product is a PET bottle. Typical examples of edible products include tablets (sugar-coated tablets, plain tablets, coated tablets, etc.) and capsules.

[0030] The marking design to be applied to an object is not particularly limited, and may include, for example, letters, designs, one-dimensional information codes such as barcodes, or two-dimensional information codes such as QR Code (registered trademark).

[0031] The following describes an example of a method for marking a design, including a barcode, on the side of the container body of a PET bottle 1. The PET bottle 1 includes, but is not limited to, a transparent container body made of polyethylene terephthalate and a thermoplastic resin cap attached to the top opening of the container body. The PET bottles 1 are loaded in a line on a conveyor line (conveyor path) 10, such as a belt conveyor, and move continuously in a predetermined direction along the conveyor line 10. The conveyor line 10 is configured to convey, for example, approximately 600 to 1,000 PET bottles 1 per minute.

[0032] A marking device 2 for carrying out the method for producing marked products according to this embodiment is installed to the side of the conveyor line 10. The marking device 2 is a device that uses laser light to mark a predetermined design on the side of a PET bottle 1 that passes through a predetermined position, and is equipped with a laser oscillator 20, a field lens 21, a beam shaping mechanism 22, a mask member 23, and a projection lens 24. The conveyor line 10 and marking device 2 constitute a production system for producing marked products.

[0033] The laser oscillator 20 is a device that generates laser light. Generally, laser light is highly directional, and it can be said that the laser light generated from the laser oscillator 20 travels in a uniform direction. The laser oscillator 20 is not particularly limited, and any of an excimer laser oscillator, a UV laser oscillator, a CO2 laser oscillator, and a YAG laser oscillator can be used. When the object is a PET bottle 1, an excimer laser oscillator is preferable as the laser oscillator 20. According to the inventors' studies, when the wavelength of the laser light is approximately 193 nm to 315 nm, the transmittance through a transparent polyethylene terephthalate plate with a thickness of approximately 0.2 mm is approximately 0%T to 0.07%T, which indicates high absorbency for polyethylene terephthalate. In contrast, when the wavelength of the laser light is 355.5 nm, the transmittance through the same polyethylene terephthalate plate is approximately 75%T, which indicates relatively low absorbency for polyethylene terephthalate. The polyethylene terephthalate plate is a sample cut out from an existing PET bottle, but the transmittance of the laser light is not thought to depend on the thickness of the sample. An excimer laser is a laser that uses a mixed gas of rare gases, halogens, etc., and has typical wavelengths of 193 nm, 248 nm, 308 nm, and 351 nm, making it suitable for marking PET bottles 1. The wavelength of the laser pulse from the laser oscillator 20 (excimer laser oscillator) according to this embodiment is 308 nm.

[0034] In this way, the laser oscillator 20 can be selected to generate laser light of an appropriate wavelength depending on the object to be marked.

[0035] The irradiation time per shot for various laser oscillators is, for example, approximately 27 nanoseconds for an excimer laser oscillator, approximately 100 nanoseconds for a TEA-CO2 laser oscillator, and approximately 50 nanoseconds for a nanosecond solid-state UV laser oscillator. Thus, excimer laser oscillators are preferred due to their short irradiation time per shot. The repetition frequency of the laser oscillator 20 can be adjusted appropriately depending on the conveyance speed of the object to be marked. For example, marking 1,000 PET bottles 1 per minute requires 17 shots per second. In this case, setting the frequency of the laser oscillator 20, which has a higher repetition frequency, to 17 Hz allows for continuous marking of objects moving on the conveyance line 10. The speed of the conveyed object, not limited to PET bottles 1, can be, for example, 1 m / s to 2 m / s.

[0036] Field lens 21 is an optical component disposed between laser oscillator 20 and beam shaping mechanism 22. Field lens 21 further aligns the direction of travel of the laser light generated by laser oscillator 20 and adjusts the size of the laser beam emitted from field lens 21. In the example of FIG. 1, the laser light is aligned so that it is parallel to the optical axis of projection lens 24 (described below), and the laser beam formed by the aligned laser light is adjusted to a size of 60 mm x 20 mm. For example, when the magnification of projection lens 24 is 2x, the size of the marking formed on the side of PET bottle 1 will be 30 mm x 10 mm.

[0037] The beam shaping mechanism 22 forms a regular path through which the laser light generated by the laser oscillator 20 (including the laser beam emitted from the field lens 21) passes. Specifically, the beam shaping mechanism 22 branches the laser light according to a predetermined pattern or blocks a portion of the laser light according to a predetermined pattern, thereby forming a regular intensity distribution of the laser light. As a result, the laser beam passing through the beam shaping mechanism 22 forms a plurality of laser beams that are parallel to the optical axis of the projection lens 24 (described later) and arranged two-dimensionally on a plane perpendicular to the traveling direction of the laser light. Examples of the beam shaping mechanism 22 that branches the laser light according to a predetermined pattern include optical members 22A and 22B shown in FIGS. 2A and 2B. Examples of the beam shaping mechanism 22 that blocks a portion of the laser light according to a predetermined pattern include a photomask 22C shown in FIG. 2C. The direction of travel of the laser light (multiple laser beams) emitted from the beam shaping mechanism 22 is the same as the direction of travel of the laser light incident on the beam shaping mechanism 22, and can be said to be unidirectional, just like the direction of travel of the laser light incident on the beam shaping mechanism 22.

[0038] The optical members 22A and 22B are each rectangular flat plates in plan view and are made of a transparent inorganic material that transmits laser light. Examples of such inorganic materials include silicon dioxide (quartz, glass) and inorganic glass other than silicon dioxide. The optical members 22A and 22B each include pattern regions 220A and 220B, in which a predetermined regular pattern is formed. Note that the surfaces of the optical members 22A and 22B on which the pattern regions 220A and 220B are formed serve as the laser light incident surfaces, and the flat surfaces on which the pattern regions 220A and 220B are not formed serve as the laser light exit surfaces.

[0039] The pattern region 220A has a regular pattern consisting of multiple flat portions 2200A and multiple curved portions 2201A adjacent to each flat portion 2200A (note that only representative portions are labeled with reference numerals). The flat portion 2200A forms a flat surface that is square in plan view, and its periphery is continuous with the curved portion 2201A. The curved portion 2201A is a curved portion that is continuous with the periphery of the two flat portions 2200A and has a semicircular shape in side view. The curved portion 2201A is recessed relative to the flat portion 2200A, and the thickness of the optical element 22A is greatest at the flat portion 2200A and smallest midway between the two adjacent flat portions 2200A (at the vertices of the semicircles formed by the curved portions 2201A). Each flat portion 2200A transmits the laser light incident on the optical element 22A as is. On the other hand, each curved surface portion 2201A refracts the laser light incident on the optical member 22A to form regularly arranged regions through which the laser light does not pass (see FIG. 10A). That is, each curved surface portion 2201A branches the laser light incident on the optical member 22A to the adjacent flat portion 2200A. As a result, the laser light incident on the optical member 22A is shaped into multiple laser beams corresponding to the flat portions 2200A.

[0040] The pattern region 220B has a regular pattern consisting of a plurality of flat portions 2200B and 2201B and a plurality of curved portions 2202B adjacent to the flat portions 2200B and 2201B, respectively (note that only representative portions are labeled with reference numerals). The flat portion 2200B has a square shape in a plan view, and its periphery is continuous with the curved portion 2202B. The flat portion 2201B also has a square shape in a plan view, and its periphery is continuous with the curved portion 2202B. However, the flat portion 2201B is recessed relative to the flat portion 2200B, and the thickness of the optical element 22B is greatest at the flat portion 2200B and smallest at the flat portion 2201B. The curved portion 2202B is a curved portion that is continuous with the periphery of the flat portion 2200B and the periphery of the flat portion 2201B, and has a quadrant shape in a cross section. Each of the flat portions 2200B and 2201B transmits the laser light incident on the optical element 22B as is. On the other hand, each of the curved portions 2202B refracts the laser light incident on the optical element 22B to form regularly arranged regions through which the laser light does not pass (see FIG. 10B). In other words, each of the curved portions 2202B branches the laser light incident on the optical element 22B to the adjacent flat portion 2201B. As a result, the laser light incident on the optical element 22B is shaped into multiple laser beams corresponding to the flat portions 2200B and 2201B.

[0041] The thickness of the optical members 22A and 22B can be, for example, 1.5 mm. The lengths of one side of the flat portion 2200A of the optical member 22A, the flat portion 2200B of the optical member 22B, and the flat portion 2201B can be designed appropriately depending on the magnification of the projection lens 24 (described later), and can be, for example, 10 μm to 300 μm. Similarly, the radii of the arcs described by the curved surface portions 2201A of the optical member 22A and the curved surface portions 2202B of the optical member 22B can be designed appropriately, and can be, for example, 1 μm to 100 μm. The radius of the arcs described by the curved surface portions 2202B is equal to the difference in elevation between the flat portions 2200B and 2201B. In addition, in optical member 22A, the distance between the centers of adjacent flat portions 2200A can be, for example, 10 μm to 100 μm, and in optical member 22ZB, the distance between the centers of adjacent flat portions 2200B and 2201B can be, for example, 15 μm to 150 μm. The number of laser beams formed by optical members 22A and 22B is not particularly limited, but can be 10,000 to 15,000, for example, when laser marks are formed at 30 μm intervals in an area of ​​30 mm × 13 mm on the surface of PET bottle 1.

[0042] The photomask 22C is a rectangular plate-like member in a planar view and has a surface 220C, which is the laser light incident surface. The photomask 22C is positioned so that the surface 220 shown in FIG. 2C is perpendicular to the laser light propagation direction. A plurality of regularly arranged square-shaped transmission regions 221 and shielding regions 222 are formed on the surface 220C. The transmission regions 221 each transmit the laser light. The shielding regions 222 shield the laser light, allowing little or no transmission. As a result, the photomask 22C as a whole forms a regular path for the laser light. In other words, the intensity distribution of the laser light on a surface perpendicular to the laser light propagation direction forms a regular pattern. Such a photomask 22C can be formed, for example, by depositing a chromium film in a predetermined pattern on one side of a synthetic quartz substrate. In other words, the transmission regions 221 can be formed in a portion of the substrate where no chromium film is deposited, and the shielding regions 222 can each be formed with a chromium film.

[0043] The size of each transmission region 221C is formed so that the size of the laser light passing through it is sufficiently small relative to the minimum size of the slits 231 in the mask member 23, which will be described later. For example, the mask member 23, which will be described later, has multiple slits 231 formed therein. In this embodiment, the narrowest slit among these slits has a width of 0.25 mm. The number of laser beams passing through these slits is preferably 10 or more rows in the width direction of the slits, more preferably 20 or more rows, and even more preferably 30 or more rows. Although this depends on the magnification of the projection lens 24, forming the laser light paths at the above-described density relative to the size of the slits 231 improves the optical readability of the barcode formed on the PET bottle 1. Note that the minimum width of the slits 231 and the preferred range of the number of rows (density) of the laser beams relative to the size of the slits 231 are merely examples in the above embodiment and may vary depending on the marking design and the object to be marked.

[0044] The photomask 22C is not limited to the above example, and the transmitting region 221 and the blocking region 222 can be formed using other materials and in other patterns. Furthermore, the photomask 22C is an example of a beam shaping mechanism 22 that blocks part of the incident laser light and forms a regular path for the laser light as a whole, and therefore such a beam shaping mechanism 22 is not limited to a photomask. Here, "blocking part of the laser light" includes absorbing part of the laser light and reflecting part of the laser light to prevent it from passing through to the conveying line 10.

[0045] Another example of the beam shaping mechanism 22 is a component in which the shielding region 222 in the photomask 22C is formed of a high-reflection mirror. Examples of high-reflection mirrors include a dielectric multilayer mirror and a metal mirror. A dielectric multilayer mirror is a reflective component that exhibits high reflectivity at a predetermined wavelength, and is configured by alternately stacking high-refractive-index dielectric films and low-refractive-index dielectric films. A metal mirror is a reflective component that reflects light by a metal coating on its surface, and examples include an aluminum mirror, a silver mirror, and a gold mirror. Among these, an aluminum mirror is preferred. For example, the beam shaping mechanism 22 may be a component obtained by forming a plurality of through-holes (as the plurality of transmission regions 221) or a plurality of transmission holes made of a material that transmits laser light in a regular pattern in the high-reflection mirror. Alternatively, the beam shaping mechanism 22 may be a component obtained by stacking the high-reflection mirror as the shielding region 222 on one side of a substrate that transmits laser light.

[0046] The mask member 23 according to this embodiment is disposed between the beam shaping mechanism 22 and the projection lens 24 or the object. FIG. 3 illustrates an example of the mask member 23. The mask member 23 in FIG. 3 is a plate-like member having a rectangular shape in a plan view and a design pattern 230 corresponding to the marking design. The mask member 23 is formed of, for example, metal and has a thickness that prevents laser light from passing through. In the example shown in FIG. 3, the design pattern 230 corresponding to the barcode is formed by multiple transparent regions indicated in black. Each of these transparent regions is formed by a rectangular or linear slit 231 penetrating the mask member 23, allowing incident laser light to pass through. As described above, the minimum size of the slit 231 is sufficiently larger than the cross-sectional area of ​​each incident laser beam, and the multiple laser beams emitted from the beam shaping mechanism 22 pass through the slit 231 as multiple laser beams. The mask member 23 according to this embodiment is disposed so that the surface shown in FIG. 3 faces the exit surface of the beam shaping mechanism 22. The mask member 23 may be arranged so as to be in contact with the beam shaping mechanism 22 or may be arranged at a distance from the beam shaping mechanism 22 .

[0047] The projection lens 24 is an optical system element placed between the mask member 23 and the object. The projection lens 24 converges the multiple laser beams emitted from the mask member 23 onto a predetermined area on the side of the PET bottle 1. In the example of FIG. 1, the projection lens 24 converges the multiple laser beams onto an area measuring 30 mm in length and 10 mm in width on the side of the PET bottle 1. The energy density of the multiple laser beams that reach the side of the PET bottle 1 is 200 mJ / cm. 2 It is preferable that the dose is 400 mJ / cm or more. 2 More preferably, it is 500 mJ / cm or more. 2 More preferably, it is 600 mJ / cm or more. 2It is particularly preferable that the above range is satisfied. However, this range is an example of marking a barcode on a PET bottle 1 using an excimer laser oscillator, and may vary depending on the type of laser, the marking design, and the object being marked. Each laser beam that reaches the side of the PET bottle 1 removes the polyethylene terephthalate on the side of the PET bottle 1, creating fine irregularities on the surface. The areas where the irregularities are formed lose their transparency due to the diffusion of visible light and turn white. This forms a marking area M on the side of the PET bottle 1, displaying the marking design according to the reduced design pattern 230.

[0048] The minute irregularities are formed from a plurality of recesses formed corresponding to flat portion 2200A, flat portions 2200B, and 2201B of beam shaping mechanism 22 or transmissive region 221, and protrusions surrounding each recess, forming a regular pattern. These irregularities have a micron-level size and height difference. From the viewpoint of improving the visibility of the marking design, it is preferable to form as many recesses per unit area as possible.

[0049] <2. Flow of production method for marked products> 4 is a flowchart showing an example of the flow of each step when carrying out the above-described method for producing marked products.

[0050] First, a mask member 23 is prepared on which a design pattern 230 corresponding to the desired marking design is formed (step S1). The size of the design pattern 230 does not need to match the actual size of the marking to be formed on the object, and can be set to a size that takes into account reduction by the projection lens 24.

[0051] Next, the beam shaping mechanism 22 and the mask member 23 are arranged in this order between the laser oscillator 20 and the conveying line 10, more specifically, between the field lens 21 and the projection lens 24 (step S2). Note that the laser oscillator 20, field lens 21, beam shaping mechanism 22, mask member 23, and projection lens 24 do not necessarily need to be arranged in a straight line, and the order in which these components are arranged refers to the order in which the laser light generated by the laser oscillator 20 passes through them. The conveying line 10 is preferably arranged so that the traveling direction of the laser light generated by the laser oscillator 20 and passed through the beam shaping mechanism 22 and mask member 23 is perpendicular to the area that will become the marking area M of the PET bottle 1 on the conveying line 10.

[0052] Next, the conveyance line 10 starts conveying the plurality of PET bottles 1 (step S3). The conveyance speed may be constant. The frequency of the laser oscillator 20 can be set appropriately in accordance with the conveyance speed.

[0053] Next, marking by the marking device 2 is started (step S4). That is, the laser oscillator 20 starts irradiating the PET bottles 1 being conveyed with laser light. Marking starts, for example, when the PET bottle 1 first passes in front of the projection lens 24. The production system according to this embodiment is equipped with an object detection sensor (not shown). The object detection sensor is configured to output a detection signal to a controller (not shown) that controls the operation of the marking device 2 when it detects that each PET bottle 1 has approached the projection lens 24. Based on the detection signal, the controller controls the timing at which the laser oscillator 20 irradiates each PET bottle 1 with laser light. The object detection sensor is not particularly limited, and any type can be used, such as a photoelectric sensor, laser sensor, ultrasonic sensor, or image sensor. Furthermore, the location at which the object detection sensor is installed is also not particularly limited.

[0054] Thereafter, one shot of laser light is repeatedly applied in the same manner to each of the PET bottles 1 that successively pass in front of the projection lens 24. This repetitive marking process stops if a certain period of time continues during which no new PET bottles 1 are detected by the object detection sensor, for example, because the conveying line 10 has stopped or there are no more PET bottles 1 passing in front of the projection lens 24 on the conveying line 10.

[0055] <3. Example of the configuration of an object and a marked product> 5 to 9 respectively show examples of objects to be laser-marked and marked products produced by applying laser marking to the objects. The objects are PET bottles 11A to 11E each having a transparent resin container body 114A to 114E. The container bodies 114A to 114E include bottoms 110A to 110E, side portions 111A to 111E extending upward from the outer peripheries of the bottoms 110A to 110E, shoulder portions 112A to 112E, and mouth portions 113A to 113E. The mouth portions 113A to 113E define upper openings. The shoulder portions 112A to 112E are continuous with the upper ends of the side portions 111A to 111E and the lower ends of the mouth portions 113A to 113E, and form inclined or curved surfaces that are inclined relative to the vertical direction.

[0056] As shown in FIG. 5, a recessed portion 115A extending along the entire periphery is formed in the side surface 111A of the PET bottle 11A. The recessed portion 115A is a portion of the side surface 111A that is recessed further inward into the container body 114A than the remaining portions of the side surface 111A. In other words, the side surface 111A defines the peripheral edges 1151A and 1152A of the recessed portion 115A and the bottom surface 1150A. The bottom surface 1150A is located at the innermost position of the inner surface of the recessed portion 115A and faces the exterior space of the container body 114A. For example, by applying laser marking to the bottom surface 1150A of the recessed portion 115A of the PET bottle 11A using the above-described method for producing a marked product, a marked PET bottle 1A is obtained, with a marking area M formed on the bottom surface 1150A. In this case, in the above-described method for producing a marked product, irradiating the PET bottle 11A with laser light during transportation includes irradiating the bottom surface 1150A with laser light. The marking area M includes a collection of multiple recesses or multiple protrusions formed by laser marks, and displays a predetermined design. The minimum depth of the recesses 115A (the distance from the periphery 1151A or periphery 1152A to the bottom surface 1150A) is not particularly limited, and may be any depth such that the protrusions of the marking area M do not reach the periphery 1151A or periphery 1152A.

[0057] As shown in FIG. 6, a recess 115B is formed in the side surface 111B of the PET bottle 11B, extending from the outer peripheral edge of the bottom surface 110B to the upper end of the side surface 111B (the boundary with the shoulder 112B). The recess 115B is a portion of the side surface 111B that is recessed more inwardly into the container body 114B than the other portions. In other words, the side surface 111B defines the peripheral edges 1151B, 1152B of the recess 115B and the bottom surface 1150B. The bottom surface 1150B faces the exterior space of the container body 114B and is the innermost surface of the recess 115B, and is preferably flat. For example, by laser marking the bottom surface 1150B of the PET bottle 11B using the above-described method for producing a marked product, a marked PET bottle 1B is obtained, with a marking area M formed on the bottom surface 1150B. In this case, in the above-described method for producing a marked product, irradiating the PET bottle 11B with laser light during transportation includes irradiating the bottom surface 1150B with laser light. The marking area M includes a collection of multiple recesses or multiple protrusions formed by laser marks, and displays a predetermined design. The minimum depth of the recesses 115B (the distance from the periphery 1151B or periphery 1152B to the bottom surface 1150B) is not particularly limited, and may be any depth such that the protrusions of the marking area M do not reach the periphery 1151B or periphery 1152B.

[0058] As shown in FIG. 7, a recessed portion 115C is formed in the side surface 111C of the PET bottle 11C. The recessed portion 115C is a portion of the side surface 111C that is recessed more inwardly into the container body 114C than the remaining portions of the side surface 111C. In other words, the side surface 111C defines the periphery 1151C of the recessed portion 115C and the bottom surface 1150C. The bottom surface 1150C faces the external space of the container body 114C and is the innermost surface of the recessed portion 115C, and is preferably flat. For example, by laser marking the bottom surface 1150C of the PET bottle 11C using the above-described method for producing a marked product, a marked PET bottle 1C is obtained with a marking area M formed on the bottom surface 1150C. In this case, in the above-described method for producing a marked product, irradiating the PET bottle 11C with laser light during transportation includes irradiating the bottom surface 1150C with laser light. 7, PET bottle 11C is shown as viewed from the side of recessed portion 115C, and PET bottle 1C is shown as viewed from the front of recessed portion 115C. Recessed portion 115C is rectangular when viewed from the front. Marking area M includes a collection of multiple recesses or multiple protrusions formed by laser marks and displays a predetermined design. The minimum depth of recessed portion 115C (the distance from periphery 1151C to bottom surface 1150C) is not particularly limited, as long as the protrusions of marking area M do not reach periphery 1151C.

[0059] As shown in FIG. 8, the side surface 111D of the PET bottle 11D has a protrusion 115D that protrudes from its outer surface. The shape of the protrusion 115D is not particularly limited, as long as it protrudes from the rest of the surrounding area to the outside of the container body 114D. For example, by performing laser marking near the protrusion 115D of the PET bottle 11D using the above-described method for producing a marked product, a marked PET bottle 1D is obtained with a marking area M formed near the protrusion 115D. In this case, in the above-described method for producing a marked product, irradiating the PET bottle 11D with a laser beam during transport includes irradiating the PET bottle 11D with a laser beam near the protrusion 115D. Note that FIG. 8 shows the PET bottle 11D viewed from the side of the protrusion 115D and the PET bottle 1D viewed from the front of the protrusion 115D. The marking area M is formed, for example, below the protrusion 115D. The maximum height of protrusion 115D relative to the outer surface of side surface portion 111D is not particularly limited as long as it protrudes outward beyond the convex portion of marking area M. It is preferable that marking area M be formed as close to the periphery of protrusion 115D as possible.

[0060] As shown in FIG. 9, the side surface 111E of the PET bottle 11E has multiple protrusions 115E protruding from its outer surface. The shape of each protrusion 115E is not particularly limited, as long as it protrudes from the surrounding area outside the container body 114D. While FIG. 9 shows six protrusions 115E arranged in a generally rectangular shape, the number and arrangement of the protrusions 115E are not particularly limited, as long as there are two or more protrusions 115E spaced apart at regular intervals. For example, by laser marking the area surrounded by the multiple protrusions 115E on the PET bottle 11E using the above-described method for producing a marked product, a marked PET bottle 1E is obtained, in which a marking area M is formed in the area surrounded by the multiple protrusions 115E. In this case, in the above-described method for producing a marked product, irradiating the PET bottle 11E with laser light during transport includes irradiating the area surrounded by the multiple protrusions 115E or the area between two protrusions 115E on the PET bottle 11E with laser light. The maximum height of each protrusion 115E from the outer surface of the side surface portion 111E is not particularly limited, and may be any height that protrudes outward beyond the convex portion of the marking region M.

[0061] <4. Features> (1) According to the method for producing marked products of the above embodiment, the beam shaping mechanism 22 can form multiple laser beams corresponding to the dot pattern formed when laser light is repeatedly irradiated along a predetermined scanning line. In other words, a desired marking can be applied to a single object with a single shot of laser light, making it easy to mark objects moving at high speed without slowing them down. Other methods for improving the speed of laser marking include installing multiple laser oscillators or splitting the laser beam onto multiple objects to simultaneously mark multiple objects. However, these methods have drawbacks, such as the increased size and cost of the equipment. They also have limitations in achieving a marking speed commensurate with the transport speed of objects on a typical transport line. In contrast, the method for producing marked products according to the present embodiment has an irradiation time of approximately 10 to 30 nanoseconds per shot, making it easy to handle even high-speed object transport speeds. Furthermore, when the irradiation time for one shot is within the above range, the distance the object moves during irradiation with laser light can be made sufficiently small compared to the dimensions of the regular uneven shape representing the marking design, thereby avoiding a situation in which the regular uneven shape is not properly formed on the object due to the influence of the conveying speed.

[0062] (2) According to the method for producing a marked product according to the above embodiment, the multiple laser beams that have passed through the beam shaping mechanism 22 are shaped into a desired design by the mask member 23. Therefore, by preparing a mask member 23 on which a design pattern corresponding to the desired design is formed, the marking design can be easily changed.

[0063] (3) According to the method for producing a marked product of the above embodiment, multiple laser beams are converged by the projection lens 24, so that marking can be performed according to the size of the object to be marked.

[0064] (4) Figures 10A to 10C are diagrams illustrating the differences in the behavior of incident laser light, using the optical element 22A, the optical element 22B, and the photomask 22C according to the above-described embodiment as examples. As can be seen from Figures 10A and 10C, unlike the beam shaping mechanism 22, which has a shielding region made of a laser light-reflecting material, such as the photomask 22C, the optical element 22A shapes the intensity distribution of the incident laser light according to a predetermined pattern to form a laser beam corresponding to a dot pattern. Therefore, compared to the photomask 22C, the incident laser light can be more effectively used for marking. Furthermore, while the material forming the shielding region of the photomask 22C may be deteriorated due to the reflection of the laser light, the flat portion 2200A and the curved portion 2201A of the optical element 22A are both made of a material that transmits the laser light, so there is no risk of deterioration. The advantages of the optical element 22A described above also apply to the optical element 22B.

[0065] (5) As described above, the marking area M formed by irradiation with laser light has a fine uneven pattern including a collection of multiple minute recesses or a collection of multiple minute protrusions formed by removing material from the surface of the object. The fine uneven pattern is easily destroyed by contact with other objects. In particular, if the marked product is a PET bottle 1, the uneven pattern may be destroyed by contact with other objects during distribution, resulting in problems such as the barcode in the marking area M not being correctly read by a barcode reader. However, in the above-mentioned PET bottles 1A-1C, since the marking area M is formed on the inner surface of the recessed portions 115A-115C, it is less likely to come into contact with other objects, and the uneven pattern in the marking area M is less likely to be destroyed. Furthermore, in the above-mentioned PET bottle 1D, since the marking area M is formed near the protrusion 115D, the protrusion 115D prevents the marking area M from coming into contact with other objects, and the uneven pattern in the marking area M is less likely to be destroyed. In the PET bottle 1E, the marking area M is formed in an area surrounded by multiple protrusions 115E, which prevents the marking area M from coming into contact with other objects, preventing the uneven pattern of the marking area M from being distorted. Therefore, the PET bottles 1A to 1E have the effect of maintaining the visibility of the design displayed in the marking area M and the readability of the information code using a code reader or the like.

[0066] (6) In PET bottle 11A, recess 115A extends along the entire circumference. This allows laser light to be applied to bottom surface 1150A of recess 115A regardless of the rotational position of PET bottle 11A relative to laser oscillator 20 during transport on conveyor line 10. Furthermore, bottom surfaces 1150B and 1150C of PET bottles 11B and 11C can be formed as flat surfaces. This eliminates the difference in focal length depending on the position at which the laser light is applied, regardless of the shape of side surfaces 111B and 111C, allowing for more accurate display of the design in marking area M. In PET bottles 11D and 11E, conveyor line 10 is configured to contact protrusions 115D and 115E at a predetermined position, allowing it to be used as a mechanism for automatically adjusting the rotational position of PET bottles 11D and 11E before passing through laser oscillator 20.

[0067] <5. Variations> Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, the following modifications are possible. Furthermore, the gist of the following modifications can be combined as appropriate.

[0068] (1) The field lens 21 and the projection lens 24 may each be made up of a single lens, or may include multiple lenses.

[0069] (2) Photomask 22C is not limited to the one having square-shaped transparent regions 221 formed therein, as in the above embodiment. Examples of other patterns of photomask 22C formed with transparent and shielding regions include the patterns shown in FIGS. 11A to 11D. FIG. 11A shows an example of a pattern in which larger square-shaped transparent regions 221a and smaller square-shaped transparent regions 221b are combined. FIG. 11B shows an example of a pattern in which regular hexagonal transparent regions 221c are regularly arranged. FIG. 11C shows an example of a pattern in which smaller square-shaped transparent regions 221d are further arranged between two adjacent transparent regions 221a in the example of FIG. 11A, forming a continuous larger transparent region and a continuous smaller transparent region 221b. FIG. 11D shows an example of a pattern in which square-shaped shielding regions 222a and 222b are formed inside and outside square-shaped transparent region 221e, respectively. It should be noted that the above-described examples of the configuration of the pattern formed by the transmitting region and the blocking region can be applied not only to the photomask 22C but also to a member in which the blocking region is formed by a high-reflection mirror.

[0070] (3) The mask member 23 is not limited to the one having the slits 231 formed therein, as in the above embodiment. For example, similar to the photomask 22C, a chromium film may be laminated in a predetermined pattern on one side of a synthetic quartz substrate to form a shielding region that blocks laser light and a transparent region that transmits laser light. Alternatively, as described in the configuration example of the beam shaping mechanism 22, the mask member 23 may be formed of a member in which through-holes corresponding to the design pattern 230 are formed in a high-reflection mirror, or a transparent hole formed of a material that transmits laser light. Alternatively, the mask member 23 may be formed of a member in which a high-reflection mirror is laminated on one side of a laser-transmitting substrate. In this case, the portion of the substrate on which the high-reflection mirror is not laminated corresponds to the design pattern 230. However, the design pattern 230 corresponding to the marking design may be formed of the entire transparent region (or the entire slit) that transmits laser light, or the entire shielding region (or the portion without the slit) that blocks laser light. When the design pattern 230 is formed over the entire shielding area or in the area where no slits are formed, the unprocessed area on the object surface surrounded by the area where fine irregularities are formed becomes the marking design. From the viewpoint of durability and the ability to form the design pattern 230 with a higher degree of freedom, the mask member 23 is preferably one in which a chrome film is laminated on a base material, a high-reflection mirror with through holes formed therein, or a high-reflection mirror is laminated on a base material.

[0071] (4) The above-described exemplary configurations of the beam shaping mechanism 22 (optical element 22A, optical element 22B, photomask 22C, a high-reflection mirror with through-holes or transmission holes formed therein, and a high-reflection mirror laminated on a substrate) and the mask element 23 (one with slit 231, one with a chromium film laminated on a substrate, a high-reflection mirror with through-holes or transmission holes formed therein, and a high-reflection mirror laminated on a substrate) can be freely combined. The beam shaping mechanism 22 and the mask element 23 may be integrally formed as a single element. More specifically, a regular pattern of a chromium film laminated on one side of a synthetic quartz substrate may serve both as a pattern for regularly dividing the laser light and as a design pattern. In another example, a regular pattern formed by a high-reflection mirror and through-holes or transmission holes, or a high-reflection mirror and a substrate, may serve both as a pattern for regularly dividing the laser light and as a design pattern. In other words, dividing the laser light by regular paths and transmitting the laser light in accordance with the design pattern 230 may be performed on the same layer. When the beam shaping mechanism 22 and the mask member 23 are configured as a single member, in the above-described method for producing a marked product, "arranging a beam shaping mechanism that forms a regular intensity distribution of the laser light" and "arranging a mask member on which a design pattern is formed" are performed simultaneously.

[0072] (5) The positional relationship between the beam shaping mechanism 22 and the mask member 23 is not limited to that described above. For example, the mask member 23 can be disposed between the projection lens 24 and the conveying line 10 (object). Furthermore, the mask member 23 can be disposed between the laser oscillator 20 and the beam shaping mechanism 22. However, from the viewpoint of forming the marking design on the object more clearly, it is preferable that the beam shaping mechanism 22 and the mask member 23 be disposed with as little space between them as possible or that they be configured as an integrated unit.

[0073] (6) The shapes of the PET bottle 1, PET bottles 11A-11E, and PET bottles 1A-1E may be modified as needed. For example, side surfaces 111A-111E may be rectangular, and shoulder surfaces 112A-112E may be horizontal. Furthermore, these may be primarily made of a thermoplastic resin other than polyethylene terephthalate, and may be opaque or translucent, or may be colored. The recessed portion 115A may be formed in the shoulder surface 112A rather than the side surface 111A. In other words, in the PET bottle 1A, the marking area M may be formed in the shoulder surface 112A. The bottom surface 1150A of the recessed portion 115A may be formed as a flat surface. The recessed portion 115B does not have to extend to the top of the side surface 111B, and may extend to the shoulder surface 112B. The recessed portion 115B may be formed in the shoulder surface 112A. That is, in PET bottle 1B, marking area M may be formed on shoulder 112B. Bottom surface 1150B of recess 115B may be formed as a curved surface. Recess 115C may be formed on shoulder 112C or bottom surface 110C. That is, in PET bottle 1C, marking area M may be formed on shoulder 112C or bottom surface 110C. Bottom surface 1150C of recess 115C may be formed as a curved surface. The shape of recess 115C in a front view may also be modified as appropriate. Note that in recesses 115A-111C, marking area M may be formed on the inner surface, and does not necessarily have to be formed on bottom surfaces 1150A-1150C. Protrusion 115D may be, for example, an endless ring, and marking area M may be formed within the area surrounded by protrusion 115D. Protrusion 115D may be formed on shoulder 112D or bottom 110D. That is, in PET bottle 1D, marking area M may be formed on shoulder 112D or bottom 110D. Protrusion 115E may be formed on shoulder 112E or bottom 110E. That is, in PET bottle 1E, marking area M may be formed on shoulder 112E or bottom 110E. At least two of the recesses 115A-111C, protrusion 115D, and protrusion 115E may be formed on the same resin container.

[0074] (7) The order of steps S1 to S4 in the above flowchart can be changed as appropriate.

[0075] (8) The positional relationship between the conveying line 10 and the marking device 2 can be changed as appropriate. That is, the configuration of the production system is not limited to that of the above embodiment and can be changed as appropriate. For example, the marking device 2 may be configured to irradiate the object with laser light from above or below the conveying line 10. The orientation of the object when conveyed by the conveying line 10 is not particularly limited. For example, in the case of PET bottles 1, the orientation can be changed as appropriate, such as conveying the object with the side of the container body facing upward. The conveying line 10 is not limited to conveying objects using a belt conveyor, but may also convey objects using buckets or boards (flights), or by using a suspender. Furthermore, the object detection sensor described in the above embodiment may be omitted, and the timing of laser light irradiation and its stop may be controlled by other means. [Example]

[0076] Examples of the present disclosure will be described below, but the present disclosure is not limited to the following examples.

[0077] <Experiment 1> A marking device 3 as shown in Fig. 12 was prepared, and a barcode marking measuring 13 mm in length and 30 mm in width was formed on the surface of a sample 4 using each of the beam shaping mechanisms 35 according to Examples 1 to 4. In addition to the beam shaping mechanism 35, the marking device 3 was equipped with an excimer laser oscillator 30, a beam shaper 31, a beam homogenizer 32, a collimator lens 33, a field lens 34, a mask member 36, a projection lens 37, and a sample stage 38. The excimer laser oscillator 30 irradiated laser light with a wavelength of 308 nm for approximately 27 nanoseconds per shot, and the energy density of the laser beam that reached the surface of the sample 4 was 500 mJ / cm per shot. 2The beam shaper 31 and beam homogenizer 32 were constructed using known beam shapers and beam homogenizers, respectively, and were configured to flatten the laser beam generated by the excimer laser oscillator 30 and to homogenize the temporal change in the intensity distribution of the beam. As shown in Figure 13, the mask member 36 was a metal plate with slits formed therein corresponding to the quiet zones and spaces of the barcode. The marking device 3 was configured to be able to form a marking of the above size with one shot on the surface of the sample 4 placed on the sample stage 38. The sample 4 was a transparent polyethylene terephthalate plate measuring 100 mm long, 80 mm wide, and 1 mm thick.

[0078] The beam shaping mechanisms 35 according to Examples 1 and 2 were glass plates on which a pattern region 220A similar to the optical element 22A of the above embodiment was formed, but the lengths of one side of the flat portions 2200A were different from each other. The beam shaping mechanisms 35 according to Examples 3 and 4 were glass plates on which a pattern region 220B similar to the optical element 22B of the above embodiment was formed, but the lengths of one side of the flat portions 2200B and 2201B were different from each other. The following Table 1 shows the dimensions of each part of the pattern region according to Examples 1 to 4. The dimensional tolerance was set to ±0.15 μm. [Table 1]

[0079] A marking device 5 as shown in Fig. 13 was also prepared, and a barcode marking measuring 13 mm in length and 30 mm in width was formed on the surface of another sample 4 (Comparative Example) using the marking device 5. The marking device 5 was equipped with a UV laser oscillator 50, an X-axis galvanometer scanner 51, a Y-axis galvanometer scanner 52, an Fθ lens 53, and a sample stage 54. The UV laser oscillator 50 emitted laser light with a wavelength of 355 nm under conditions of an output of 3 W and a frequency of 100 kHz, so that the irradiation diameter per shot on the surface of the sample 4 was 30 µm. The energy density of the laser beam that reached the surface of the sample 4 was 5.7 J / cm per shot. 2 On the surface of the sample 4, markings were formed in the portions corresponding to the slits in the mask member 36 while controlling the X-axis galvano scanner 51 and the Y-axis galvano scanner 52 so that the laser marks formed by the irradiation of each shot would not overlap each other and would be formed at maximum density.

[0080] <Result 1> The entire markings formed using the marking device 3 and the entire markings formed using the marking device 5 were observed with the naked eye, and it was confirmed that the intended barcode design was formed using opaque white areas and transparent areas in both markings. Next, the time required to form a marking on the sample 4 using the marking device 3 and the marking device 5 was compared. When the marking device 3 was used, a marking could be formed with one shot of laser irradiation (approximately 27 nanoseconds) regardless of which of the beam shaping mechanisms 35 according to Examples 1 to 4 was used. In contrast, when the marking device 5 was used, it took approximately 5.5 seconds to form a marking of the same size and design. This confirmed that the marking device 3 equipped with the beam shaping mechanism 35 according to Examples 1 to 4 can form a marking of a predetermined design sufficiently quickly on an object being transported at a constant speed.

[0081] Furthermore, for the markings formed using the beam shaping mechanisms 35 of Examples 1 to 4, the processing depth (μm) was measured using a 3D measuring laser microscope (OLS, manufactured by Olympus Corporation), and the reflection value (%) of the marked barcode was measured using a barcode verifier (STRATIX Laser Xminer). The results are shown in Table 2 below. The reflection value (%) indicates how much incident infrared light is reflected in each quiet zone and each space of the barcode, and if the minimum value is 80% or more, it can be said that there is no problem with reading by a barcode reader. The values ​​in Table 2 are the average values ​​for each quiet zone and each space. From Table 2, it was confirmed that although there were differences in processing depth between Examples 1 to 4, markings could be formed to a degree that did not interfere with reading as a barcode. [Table 2]

[0082] For reference, Fig. 15 shows an image captured by an electron microscope of a portion of a marking (a portion corresponding to a quiet zone of a barcode) formed using the marking device 3 equipped with the beam shaping mechanism 35 according to Example 1. As shown in Fig. 15, on the surface of the sample 4, portions that turn white due to the laser light reaching thereto and portions that remain transparent due to the laser light not reaching thereto form a regular pattern. This confirms that the beam shaping mechanism 35 has formed a regular intensity distribution of the laser light corresponding to the pattern formed by the flat and curved portions.

[0083] <Experiment 2> Markings were formed on the surface of Sample 4 under the same conditions as in Experiment 1, except that the energy density of the laser light was changed (Examples 5 to 8). The energy density was set to the following conditions 1 to 4. Condition 1: 200mJ / cm 2 Condition 2: 400mJ / cm 2 Condition 3: 600mJ / cm 2 Condition 4: 800mJ / cm2 For each of the energy densities under conditions 1 to 4, the processing depth (μm) of the formed marking and the reflection value (%) of the marked barcode were measured in the same manner as in Experiment 1.

[0084] <Result 2> The results are shown in the following Table 3. For reference, images of markings formed at each energy density taken with an electron microscope are shown in FIGS. 16A to 16D. [Table 3]

[0085] From the results in Table 3, it was found that the higher the energy density, the deeper the processing depth. It was also found that the deeper the processing depth, the more likely protrusions were to be formed on the surface of Sample 4, as shown in Figures 16A to 16D. When more or larger protrusions were formed, the contrast between the white and transparent parts on the surface of Sample 4 tended to become stronger. In addition, the reflectance value was 0.01 at an energy density of 200 mJ / cm 2 However, it can be said that it is quite high, 400mJ / cm 2 It was confirmed that the value becomes higher when the value is above this level. [Explanation of symbols]

[0086] 1, 1A-1E, 11A-11E PET bottles 2. Marking device 10 Conveyor line 20 Laser oscillator 21 Field Lens 22 Beam shaping mechanism 22A Optical Components 22B Optical Components 22C Photomask 23 Mask material 24 projection lenses 220 pages 220A, 220B pattern area 221, 221a~e transmission area 222, 222a, 222b shielding area 230 Design Patterns 231 Slit 2200A flat part 2201A Curved section 2200B, 2201B flat part 2202B Curved section

Claims

1. conveying an object along a conveying path; a beam shaping mechanism is disposed between a laser oscillator and the transport path, the beam shaping mechanism branching the laser beam generated from the laser oscillator according to a predetermined pattern or blocking a part of the laser beam according to a predetermined pattern, thereby forming a regular intensity distribution of the laser beam; placing a mask member between the laser oscillator and the transport path, the mask member having a design pattern formed thereon that transmits or blocks the laser light in accordance with a design of the marking to be performed on the object; generating the laser light from the laser oscillator, and irradiating the laser light that has passed through the beam shaping mechanism and the mask member onto the object being transported; Equipped with The traveling direction of the laser light emitted from the beam shaping mechanism is unidirectional and is the same as the traveling direction of the laser light incident on the beam shaping mechanism. How to produce marked products.

2. The laser oscillator may be an excimer laser oscillator, a UV laser oscillator, a CO 2 a laser oscillator or a YAG laser oscillator; 10. A method for producing a marked product according to claim 1.

3. the beam shaping mechanism is an optical member made of a material that transmits the laser light, and having a regular pattern consisting of a flat portion that transmits the laser light and a curved surface portion that is adjacent to the flat portion and that branches the laser light to the adjacent flat portion; 3. A method for producing a marked product according to claim 1 or 2.

4. the beam shaping mechanism is a photomask having a regular pattern consisting of a blocking region that blocks the laser light and a transmitting region that transmits the laser light; 3. A method for producing a marked product according to claim 1 or 2.

5. the beam shaping mechanism is a member on which a regular pattern is formed, the regular pattern being made up of a blocking region that blocks the laser light and a transmitting region that transmits the laser light; The shielding area is formed of a highly reflective mirror.

3. A method for producing a marked product according to claim 1 or 2.

6. the mask member is a photomask on which the design pattern is formed, the design pattern including a blocking region that blocks the laser light and a transmitting region that transmits the laser light; 3. A method for producing a marked product according to claim 1 or 2.

7. the mask member is a member on which the design pattern is formed, the design pattern being composed of a blocking region that blocks the laser light and a transmitting region that transmits the laser light; The shielding area is formed of a highly reflective mirror.

3. A method for producing a marked product according to claim 1 or 2.

8. The beam shaping mechanism and the mask member are integrally configured.

3. A method for producing a marked product according to claim 1 or 2.

9. The object comprises a resin container body including a bottom surface, a side surface extending upward from an outer peripheral edge of the bottom surface, a mouth portion defining an upper opening, and a shoulder portion continuing from the side surface and the mouth portion; a recess is formed in at least one of the bottom surface portion, the side surface portion, and the shoulder portion; irradiating the object being transported with the laser light that has passed through the beam shaping mechanism and the mask member includes irradiating the laser light onto an inner surface of the recessed portion.

3. A method for producing a marked product according to claim 1 or 2.

10. The recessed portion is formed in the side surface portion.

10. The method for producing a marked product according to claim 9.

11. The recessed portion extends around the entire periphery of the side surface.

10. The method for producing a marked product according to claim 9.

12. The recessed portion extends from the outer peripheral edge of the bottom surface portion to the upper end of the side surface portion. The method for producing a marked product according to claim 10.

13. an inner surface of the recessed portion forms a flat surface facing an external space of the container body at an innermost position, and irradiating the inner surface of the recessed portion with the laser light includes irradiating the flat surface with the laser light.

10. The method for producing a marked product according to claim 9.

14. The object comprises a resin container body including a bottom surface, a side surface extending upward from an outer peripheral edge of the bottom surface, a mouth portion defining an upper opening, and a shoulder portion continuing from the side surface and the mouth portion; a protrusion protruding from an outer surface is formed on at least one of the bottom surface, the side surface, and the shoulder portion; irradiating the object being transported with the laser light that has passed through the beam shaping mechanism and the mask member includes irradiating the laser light near the protrusion.

3. A method for producing a marked product according to claim 1 or 2.

Images