KR102577702B1 - Retro-reflective sheet with wireless recognition and preparation method thereof - Google Patents

Abstract

The present invention relates to a retroreflective sheet capable of wireless recognition and an in-mold injection molded product for manufacturing the same. In particular, it has excellent visibility through the retroreflection function, and at the same time, it is difficult to film due to too bright light from parking lot cameras or speed cameras. By inserting RFID into retroreflective vehicle license plates, vehicle information can be accurately confirmed even in situations where camera photography is difficult. This is about a retroreflective vehicle license plate that enables excellent wireless recognition for both visual and electronic identification.

Description

Retro-reflective sheet capable of wireless recognition and method of manufacturing the same {RETRO-REFLECTIVE SHEET WITH WIRELESS RECOGNITION AND PREPARATION METHOD THEREOF}

The present invention relates to a retroreflective sheet capable of wireless recognition. In particular, it has excellent visibility through the retroreflection function, and at the same time, RFID can be applied to retroreflective vehicle license plates that were difficult to photograph due to too bright light in parking lot cameras or speed cameras. It is about a retro-reflective sheet that enables excellent wireless recognition for both visual and electronic identification by enabling accurate confirmation of vehicle information even in situations where insertion and camera photography are difficult. Additionally, the examples below relate to technology for manufacturing a retroreflective sheet capable of wireless recognition using in-mold injection.

The RETRO-REFLECTION function has the characteristic of allowing light coming from outside to return in the direction it came from. Retroreflectors are usually formed in the form of a sheet, processed into a desired shape or pattern on the surface of the body of the adherend, and attached to selected parts of uniforms such as road signs or firefighters by heat pressing or sewing to improve visibility (visibility). Visibility has been improved so that the surrounding environment can be easily identified even in dark places. Therefore, when a retroreflective sheet is attached to the clothing worn by people working on roads or in dangerous places, such as environmental sanitation workers, firefighters, police officers, factory workers, construction site workers, and safety personnel in various areas, the wearer's location can be revealed to people around them. can be reliably confirmed, which has a great effect on the protection and safety of the wearer.

Additionally, retroreflective sheets can be applied to car license plates. It is difficult for other vehicles or pedestrians driving nearby to easily identify a car's license plate because the surrounding area is dark at night. Therefore, technology is being developed to improve visibility at night by applying retroreflective sheets to car license plates.

However, in the case of license plate photographing devices such as parking lot cameras or speed cameras, when infrared light is irradiated to a vehicle license plate with a retroreflective sheet attached for photography, the light retroreflected from the vehicle license plate is so intense that the captured picture becomes too bright. As it was filmed, there was a problem in identifying the license plate.

Meanwhile, RFID (Radio Frequency IDentification) is a system that uses radio waves from tags attached to objects to recognize the object's identification and surrounding environment information and provides various services such as remote processing, management, and information exchange between objects. . This RFID system is largely composed of chips, tags, readers, middleware, and application service platforms, and operates at various frequencies such as low frequency (125kHz, 135kHz), high frequency (13.56MHz), microwave (433MHz, 860~960MHz), and microwave (2.45GHz). Bands are used, and each method and scope of use is different. Among these, the UHF (ULTRA HIGH FREQUENCY) band, which is an ultra-high frequency band, is capable of medium-to-long-distance signal transmission and relatively high-speed transmission, so it is expanding into all areas of life, including distribution and logistics.

In addition, in the process of manufacturing retroreflective sheets, when they are made into sheets and used by heat compression or sewing, there is a problem that the sheets are easily opened or torn due to low durability, so there is a need to develop technology to overcome these problems. This is being demanded

Accordingly, in order to maintain the advantages of retro-reflective vehicle license plates and at the same time overcome the disadvantages of license plate photography, the present inventor developed a method of transmitting vehicle information electronically through RFID insertion of vehicle license plates, thereby enabling RFID imaging even at high brightness where cameras cannot capture images. The present invention was completed by confirming that it was possible to obtain vehicle information through . Furthermore, a manufacturing method for retroreflective in-mold injection molding that can be manufactured in any shape was completed.

Republic of Korea Patent Publication No. 10-1849889 Republic of Korea Patent Publication No. 10-2021-0086572

The problem of the embodiments is to provide a retroreflective sheet capable of wireless recognition. In particular, it has excellent visibility through the retroreflective function, and at the same time, it is difficult to photograph a retroreflective vehicle due to too bright light from a parking lot camera or a speed camera. By inserting RFID into the license plate, vehicle information can be accurately confirmed even in situations where camera photography is difficult. We provide a retroreflective sheet that enables excellent wireless recognition for both visual and electronic identification and a vehicle license plate using the same.

In addition, in the method of manufacturing the retroreflective sheet capable of wireless recognition, a retroreflective in-mold injection product is provided, and in particular, it has excellent visibility through the retroreflection function, and at the same time, the in-mold injection method allows for certain conditions depending on the mold. The goal is to provide retroreflective in-mold injection molding products that can be easily manufactured in any shape.

As an aspect for solving the above problem, the present invention

adhesive (710);

a reflective layer 650 formed on top of the adhesive and reflecting incident light in the visible light range;

a focusing resin layer 640 formed on the top of the reflective layer to focus incident light at the interface with the reflective layer;

A refractive lens layer 630 that is attached and formed on the focusing resin layer to retroreflect light in the visible region;

A refractive lens adhesive layer 620 that allows the surface film layer to be adhered to the refractive lens layer;

an infrared reflection layer 660 formed on top of the refractive lens adhesive layer;

An adhesive layer 610 formed on the top of the refractive lens adhesive layer to prevent the refractive lens layer from being damaged;

A resin film 431 formed on the top of the adhesive layer, an antenna 432 on which a circuit is formed and printed on the resin film 431 through conductive ink, high-temperature deposition, or metal foil etching, and an RFID chip connected to the antenna. (433), a wireless recognition resin film layer (430) made of a protective resin film (434) that protects the antenna and the RFID chip;

It includes; a printing layer 500 laminated on the wireless recognition resin film layer 430,

The printed layer includes a first area vertically corresponding to the area where the antenna 432 is located within the wireless recognition resin film layer, and a second area excluding the first area,

The first region and the second region of the printed layer have different reflected visible light wavelengths, providing a retroreflective sheet capable of wireless recognition.

According to one embodiment,

a resin film adhesive layer 440 that enables the wireless recognition resin film layer 430 and the printing layer 500 to be bonded; A hard coating 420 formed on the top of the metal thin film layer; And it may include a base film layer 410 formed on top of the hard coating 420.

According to one embodiment, the printing layer includes a metal thin film layer 520 formed on top of the resin film adhesive layer; A UV pattern printing layer 510 formed on top of the metal thin film layer; And it may further include a screen color printing layer 530.

According to one embodiment, the refractive lens layer 630 includes a plurality of glass beads or microprisms, and one or more infrared blocking thin films 631 are placed on the top or bottom of the surface of the plurality of bead-shaped lenses or prism-shaped lenses. ) is formed, and the infrared blocking thin film is SiO ₂ , MB ₂ O ₅ , TiO ₂ , ZnS, ZnO, Al ₂ O ₃ , ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , CaF ₂ and Na ₃ AlF ₆ It may be deposited with one or more materials selected from among.

According to one embodiment, the metal thin film layer 520 is printed with a coating solution containing metal oxide particles, and the metal oxide particles are SiO ₂ , TiO ₂ , ZnS, ZnO, Al ₂ O ₃ , ZrO ₂ , and Ta ₂ It may be deposited with any one material selected from O ₅ , Nb ₂ O ₅ , CaF ₂ and Na ₃ AlF ₆ .

According to one embodiment, it may additionally include an electromagnetic wave shielding layer formed at the bottom of the external adhesive layer to prevent RFID chip errors caused by electromagnetic waves emitted from the vehicle.

According to one embodiment, the resin film adhesive layer is 60 to 80㎛, the resin film is 0.2 to 0.3mm, the protective resin film is 0.1 to 1mm, the base film adhesive layer is 80 to 100㎛, and the base film layer is 40㎛. It has a thickness of 120 μm to 120 μm, and the conductive ink of the antenna may be any one conductive ink selected from silver paste, carbon paste, silver-coated copper paste, copper paste, nickel paste, and ceramic paste, and the metal foil of the metal foil etching is It may be copper foil or aluminum foil, and the RFID chip and antenna may be placed on the top or left side of the license plate.

According to one embodiment, the RFID chip uses the UHF (Ultra High Frequency) band, which is an ultra-high frequency band, and may specifically use the band of 908.5 to 914 MHz.

As another aspect to solve the above problem,

An in-mold film preparation step of preparing an in-mold film including a hard coating layer 1, a printing layer, and an adhesive layer;

Hard coating layer 2, preparing a retroreflective sheet capable of wireless recognition according to claim 1 formed on top of the hard coating layer 2;

A mixed sheet manufacturing step of manufacturing a mixed sheet by bonding the adhesive layer of the in-mold film and the surface film layer of the retroreflective sheet;

A mixed sheet mounting step of mounting the mixed sheet on an injection mold;

A mixing sheet deformation step of bending the mixing sheet to contact the inner surface of the mold;

An injection material injection step of injecting molten injection material into the cavity of the mold;

an injection material curing step of curing the molten injection material to form an injection molded product in which the mixed sheet and the cured injection material are bonded;

A curing step of curing the hard coating layer 1 of the mixed sheet adhered to the injection molded product; and

A product extraction step of separating the cured injection molded product from the mold; It provides a method of manufacturing a retroreflective in-mold injection product comprising a.

Specifically, the in-mold film is an IMD film (in mold decoration) including a base release film, a hard coating layer 1 laminated on the base release film, a printing layer laminated on the hard coating layer 1, and an adhesive layer laminated on the printing layer. film) or an IML film (in It may be a mold label film).

Specifically, the mixing sheet manufacturing step further includes the step of surface treatment with a primer, corona, or plasma to improve adhesion between the hard coating layer 2 and the injection material, and the retroreflective sheet is made of glass beads or micro It may be formed including a prism.

Specifically, the base release film is 30 to 50㎛, the hard coating layer 1 is 30 to 60㎛, the printing layer is 40 to 60㎛, the adhesive layer is 40 to 60㎛, and the hard coating layer 2 is 30 to 60㎛, The reflection layer has a thickness of 10 to 60 μm, the focusing resin layer has a thickness of 80 to 120 μm, the refractive lens layer has a thickness of 50 to 100 μm, the refractive lens adhesive layer has a thickness of 70 to 90 μm, and the surface film layer has a thickness of 40 to 60 μm. It may be.

The device according to one embodiment may be combined with hardware and controlled by a computer program stored in a medium to execute any one of the above-described methods.

The retroreflective sheet capable of wireless recognition according to the present invention has excellent visibility at night through the retroreflection function, and allows vehicle information to be accurately confirmed through RFID even in situations where camera shooting is difficult, enabling visual and electronic identification. All are excellent. In particular, the RFID chip and antenna are stably fixed within the license plate, and wireless signals using electromagnetic waves can be clearly transmitted to the terminal. RFID communication can be supported at different frequencies depending on the arrangement of the antenna, and the antenna can be deployed widely to be compatible with various RFID standards, which is useful for improving compatibility and recognition rate.

In addition, the retroreflective in-mold injection product for manufacturing the retroreflective sheet capable of wireless recognition has superior durability than the retroreflective sheet attached by conventional heat compression and can be manufactured in various shapes depending on the mold, so it can be manufactured in various shapes that require retroreflection. Can be used in places.

Figure 1 is a diagram for explaining a retroreflective sheet capable of wireless recognition according to an embodiment.
Figure 2 is a diagram showing a retroreflective sheet according to one embodiment.

Hereinafter, embodiments will be described in detail with reference to the attached drawings. However, various changes can be made to the embodiments, so the scope of the patent application is not limited or limited by these embodiments. It should be understood that all changes, equivalents, or substitutes for the embodiments are included in the scope of rights.

Specific structural or functional descriptions of the embodiments are disclosed for illustrative purposes only and may be modified and implemented in various forms. Accordingly, the embodiments are not limited to the specific disclosed form, and the scope of the present specification includes changes, equivalents, or substitutes included in the technical spirit.

Terms such as first or second may be used to describe various components, but these terms should be interpreted only for the purpose of distinguishing one component from another component. For example, a first component may be named a second component, and similarly, the second component may also be named a first component.

When a component is referred to as being “connected” to another component, it should be understood that it may be directly connected or connected to the other component, but that other components may exist in between.

The terms used in the examples are for descriptive purposes only and should not be construed as limiting. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by a person of ordinary skill in the technical field to which the embodiments belong. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless explicitly defined in the present application, should not be interpreted in an ideal or excessively formal sense. No.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. The present embodiments only serve to ensure that the disclosure of the present invention is complete and that common knowledge in the technical field to which the present invention pertains is not limited. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims.

In the embodiments of the present invention, unless otherwise defined, all terms used herein, including technical or scientific terms, are the same as those commonly understood by a person of ordinary skill in the technical field to which the present invention pertains. It has meaning. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless clearly defined in the embodiments of the present invention, have an ideal or excessively formal meaning. It is not interpreted as

The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings for explaining embodiments of the present invention are illustrative, and the present invention is not limited to the matters shown. Additionally, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. When 'includes', 'has', 'consists of', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, the plural is included unless specifically stated otherwise.

When interpreting a component, it is interpreted to include the margin of error even if there is no separate explicit description.

The size and thickness of each component shown in the drawings are shown for convenience of explanation, and the present invention is not necessarily limited to the size and thickness of the components shown.

Each feature of the various embodiments of the present invention can be partially or fully combined or combined with each other, and as can be fully understood by those skilled in the art, various technical interconnections and operations are possible, and each embodiment may be implemented independently of each other. It may be possible to conduct them together due to a related relationship.

As one embodiment, the retroreflective sheet capable of wireless recognition of the present invention includes a retroreflective layer 600 and a wireless recognition resin film layer 430. The retroreflective sheet of the present invention is preferably used for automobile license plates.

The retroreflective layer 600 includes an external adhesive layer 660, a reflective layer 650, a focusing resin layer 640, a refractive lens layer 630, a refractive lens adhesive layer 620, and a point and adhesive layer 610.

The retroreflective layer refers to a layer with a reflection phenomenon in which a radiation source reflects in the incident direction and returns over a wide range of incident directions, and is formed by including glass beads or microprisms (especially including in the refractive lens layer). You can.

The retroreflective sheet of the present invention can be attached to an automobile substrate through an adhesive 710. The adhesive is also called a mold layer. The adhesive is resin, and adhesives of various materials can be used. In some embodiments, adhesive 710 may include an aluminum sheet.

An electromagnetic wave shielding layer can be formed at the bottom of the adhesive to prevent RFID chip errors caused by electromagnetic waves emitted from vehicles. The material of the electromagnetic wave shielding layer can be used without limitation as long as it is a typical electromagnetic wave shielding paint.

Reflective layer 650 may be formed using, for example, metal deposition. Aluminum, silver, etc. can be used as the metal. Alternatively, the reflective layer may comprise a multilayer reflective coating disposed on the microspheres, such as described in U.S. Pat. No. 6,243,201 to Fleming, for example. The thickness of the reflective layer may be about 10 to about 60 μm. When visible light enters the retroreflector from the normal direction, the visible light passes through the refractive lens, is reflected by the reflective layer, and is redirected toward the light emitting source. When infrared light is incident on a retroreflector from a large angle of incidence (e.g., an angle of incidence displaced from near the normal), the infrared light passes through the refractive lens, and at least a portion of the infrared light is absorbed and/or scattered by the infrared blocking layer. do. In this way, the retroreflection of infrared light can be reduced or suppressed, which can have the effect of further improving the visibility of visible light.

The focusing resin layer 640 is a layer partially containing the refractive lens layer 630, and the refractive lens plays a role in displaying the function of retroreflection. The focus resin layer may contain any transparent resin with sufficient moldability. Exemplary materials used in the focusing resin layer include, for example, resins, alkyd resins, polyester resins, melamine resins, mixtures thereof, etc. The focusing resin layer preferably has a thickness of about 5% to about 95% of the size of the refractive lens, more preferably about 20% to about 70% of the size of the refractive lens. Dyes or pigments may be added to the focal resin layer. Specifically, as a pigment, titanium dioxide powder, silicon dioxide powder, or all of these powders may be added to the focusing resin layer.

The refractive lens layer includes a plurality of glass beads or microprisms, and one or more infrared blocking thin films 631 are formed on the top or bottom of the surface of the plurality of bead-shaped lenses or prism-shaped lenses. is deposited with one or more materials selected from SiO ₂ , MB ₂ O ₅ , TiO ₂ , ZnS, ZnO, Al ₂ O ₃ , ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , CaF ₂ and Na ₃ AlF ₆ It may be.

The refractive lens layer 630 may also be made of other optically transparent materials, such as resin materials. Although the drawings show a completely uniform arrangement of refractive lenses with identical dimensions within a single layer, the sizes of the refractive lenses may be varied, and the gap between adjacent refractive lenses may be varied, as long as the effect of the present invention is not lost. It can be. The average particle size of a refractive lens can be determined using a particle size measurement device that uses laser diffraction scattering methods.

The refractive lens adhesive layer 620 serves to bond the refractive lens layer 630 and the point and adhesive layer 610. The adhesive layer may be formed from a transparent adhesive composition containing a urethane or urethane-acrylic adhesive resin and an isocyanate-based curing agent.

The infrared reflecting layer 660 is any one selected from SiO ₂ , MB ₂ O ₅ , TiO ₂ , ZnS, ZnO, Al ₂ O ₃ , ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , CaF ₂ and Na ₃ AlF ₆ It may be formed by deposition or coating with the above materials. Specifically, the metal oxide thin film is silicon dioxide (SiO ₂ ) It may be formed by repeatedly depositing a thin film and a niobium oxide (Nb ₂ O ₅ ) thin film in pairs. The infrared reflective layer may exhibit a synergistic effect with the infrared blocking thin film 631. The infrared reflecting layer may or may not have the same components as the infrared blocking thin film described above. The infrared blocking layer may have a thickness of 100 to 100,000 Å. The infrared reflecting layer may be formed as an additional layer.

The point adhesive layer 610 serves to protect the refractive lens layer 630, and like the external adhesive layer 660, it is made of silsesquioxane, acrylate, methacrylate, epoxy, urethane, silicone, and melamine resin. It may include one or more of the group, but materials with high light transmittance (90% or more) that are not inhibited by retroreflection may be used. The adhesive layer may have a thickness of 1 to 100 ㎛, preferably 10 to 30 ㎛.

A printing layer 500 laminated on the singi wireless recognition resin film layer 430 is included. The printed layer may include a first area vertically corresponding to the area where the antenna 432 is located within the wireless recognition resin film layer, and a second area excluding the first area.

Based on FIG. 2, antennas 432 expressed in different colors may mean antennas composed of different patterns (e.g., number of turns) to support RFID communication of different frequencies (or standards). Additionally, the antenna 432 may be understood as an RFID pattern.

The first and second regions of the printed layer may have different reflected visible light wavelengths. The color of the printed layer can be distinguished in area 1 and area 2.

Through this, the part where the RFID pattern is formed can be confirmed even through the printed layer.

As a component of the printing layer, a metal thin film layer 520 formed on the point and adhesive layer and deposited for infrared or color expression may be included. The metal thin film layer is deposited to block infrared rays or express color. The metal thin film layer is formed by depositing any one material selected from SiO ₂ , TiO ₂ , ZnS, ZnO, Al ₂ O ₃ , ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , CaF ₂ and Na ₃ AlF ₆ You can. The deposition may be performed by sputtering or a method commonly used in the art. The infrared blocking layer may be made of an infrared non-transparent material. Exemplary infrared opaque materials include near-infrared radiation absorbers that absorb or scatter near-infrared radiation (e.g., wavelengths from about 760 nm to about 1500 nm). Transmission of infrared radiation can be measured using a spectrophotometer. Exemplary organic infrared opaque materials include, for example, carbon black, polymethine type compounds, pyrylium type compounds, thiopyrylium type compounds, squalium type compounds, croconium type compounds, azulenium type compounds. Compounds, phthalocyanine type compounds, tetrahydrocholine type compounds, dithiol metal complex salt type compounds, naphthoquinone type compounds, antimonate type compounds, anthraquinone type compounds, triphenylmethane type compounds, amine type compounds, dimonium type compounds, etc. Exemplary inorganic infrared opaque materials include, for example, antimony tin oxide (ATO), indium tin oxide (ITO), LaB ₆ , tin oxide, antimony tin oxide, titanium dioxide, iron oxide, aluminum, tin-lead alloy, gold, Compounds such as silver and the like are included. Specifically, the infrared blocking layer is printed with a coating solution containing metal oxide particles, and the metal oxide particles are antimony tin oxide (ATO). It may be nanoparticles or indium tin oxide (ITO) nanoparticles.

As one component of the printing layer, a UV pattern printing layer 510 and a screen color printing layer 530 may be additionally included on top of the metal thin film layer 520. The UV pattern printing layer 510 is used to create a three-dimensional effect by forming a pattern in the UV curing liquid. Patterns can be formed in UV curing liquid by UV molding or heat curing coating. It can be formed through equipment such as microgravure, gravure, flexo, and silk printing. The screen color printing layer 530 is a screen color printed layer using a method commonly used in the art, and can be formed using a method commonly used in the art using equipment such as micro gravure, gravure, flexo, and silk printing. The UV pattern printing layer and the screen color printing layer may have a thickness of 1 to 60 ㎛, preferably 10 to 20 ㎛.

The resin film adhesive layer 440 serves to bond the retroreflective portion 600 and the wireless recognition resin film layer 430. The adhesive layer may be formed from a transparent adhesive composition containing a urethane or urethane-acrylic adhesive resin and an isocyanate-based curing agent, and may have a thickness of 60 to 80 μm.

The wireless recognition resin film layer 430 includes a resin film 431, an antenna 432, an RFID chip 433, and a protective resin film 434.

The resin film 431 may serve as a substrate capable of wireless communication by printing the antenna 432 and placing the RFID chip 433. The resin film may have a thickness of 0.2 to 0.3 mm.

The antenna 432 may be formed and printed as a circuit on the resin film 431 using conductive ink, high-temperature deposition, or metal foil etching. The conductive ink may be silver paste, carbon paste, silver-coated copper paste, copper paste, or nickel. It may be any one conductive ink selected from paste and ceramic paste, and the metal foil for etching the metal foil may be copper foil or aluminum foil.

The RFID chip 433 refers to a chip that receives a signal transmitted from an RFID reader through wireless communication, receives power, and then transmits its own chip-specific information stored in advance to the reader. RFID technology consists of tags, antennas, and readers. The tags and antennas transmit information wirelessly from several to tens of meters, and the reader receives this signal, decodes the product information, and sends it to the computer. The sent data is processed by sending the recognized data to a computer system. Therefore, all tagged products can be automatically checked or tracked anytime, anywhere, and the tag has a built-in memory so information can be updated and modified. RFID tags can be divided into active types that require power depending on the presence or absence of power supply, and passive types that are operated by the electromagnetic field of the reader without direct power supply from the inside or outside. The active type has the advantage of reducing the power required for the reader and increasing the recognition distance from the reader. However, because it requires a power supply, its operating time is limited and it is more expensive than the passive type. On the other hand, the passive type is much lighter and cheaper than the active type, and can be used semi-permanently, but has the disadvantage of having a short recognition distance and consuming much more power in the reader. RFID technology uses several wavebands, including low frequency (125 kHz, 135 kHz), high frequency (13.56 MHz), microwave (433 MHz, 860~960 MHz), and microwave (2.45 GHz), and each has a different usage method and application range. Among these, the UHF (ULTRA HIGH FREQUENCY) band, which is an ultra-high frequency band, is capable of mid- to long-distance signal transmission and relatively high-speed transmission, and can also be used in passive RFID tags up to 2 to 3 meters, providing a sufficient distance between the car license plate and the RFID reader. It is possible to recognize license plates of vehicles on the road. The RFID chip may be installed on the resin film at a location where it can be connected to the antenna. The RFID chip uses the UHF (Ultra High Frequency) band, which is an ultra-high frequency band, and may specifically use the band of 908.5 to 914 MHz.

It is preferable that the RFID chip and antenna are placed at the top of the retroreflective portion above and below the retroreflective sheet. This is because it is desirable for the RFID chip and antenna to be located on the outside of the license plate in terms of recognition rate.

In the cross-section of the retroreflective sheet, the RFID chip can be placed anywhere, preferably in the middle. The antenna can be placed and formed without limitation as long as it is in a shape that can generate an electromagnetic field in the vehicle license plate when approaching the terminal. Preferably a loop antenna may be used. It is advantageous to place it close to the entire area of the vehicle license plate.

The protective resin film 434 serves to protect the antenna and RFID chip from damage. Additionally, since the thickness of the RFID chip is 0.08 to 1 mm, the protective resin film may have a thickness of 0.1 to 1 mm. The material of the resin film 431 and the protective resin film 434 may be any one selected from PVC, PET, epoxy, and urethane, which are commonly used in credit cards, transportation cards, and wireless communication devices.

The hard coating 420 is formed at the bottom of the base film layer 410. The hard coating can be formed by UV or heat curing coating and can be formed through equipment such as comma coating, slot die, micro gravure, or gravure. It may be formed from a transparent adhesive composition containing a urethane or urethane-acrylic adhesive resin and an isocyanate-based curing agent, and may have a thickness of 1 to 60 ㎛, preferably 10 to 20 ㎛.

The base film layer 410 serves to protect the wireless recognition resin film layer from damage. The base film layer is preferably made of thermosetting or thermoplastic materials. The thermosetting or thermoplastic materials include polycarbonate, polyethylene naphthalate, polyethylene terephthalate, polyester, polyamide, polystyrene, and polymethyl methacrylate. (polymethyl methacrylate, polyurethane, polyvinyl chloride (PVC), polyethylene, polypropylene, and polyfluorovinylidene, polyfluorovinyl) It includes one or more selected substances, preferably polyethylene terephthalate, polyvinyl chloride, etc. The base film layer may have a thickness of 10 to 150 μm, preferably 40 to 120 μm.

The retroreflective sheet capable of wireless recognition according to an embodiment of the present invention has both a retroreflective function and an RFID wireless communication function, so that RFID wireless communication can compensate for the disadvantage of difficult camera shooting when the retroreflective sheet is in high brightness conditions. In the case of medium/low brightness conditions, visible light is retroreflected through the infrared blocking layer and infrared rays are reduced or suppressed to improve the visibility of the vehicle license plate, so the retroreflective vehicle license plate can be applied regardless of brightness. do.

When the retroreflective sheet capable of wireless recognition is used within a range that can be recognized by a camera, it can cross-check the camera's vehicle information and vehicle information through RFID, thereby reducing recognition errors in vehicle information and preventing forgery and alteration of license plates. You can have it.

Meanwhile, a method of manufacturing a retroreflective in-mold injection product will be described. First, prepare the in-mold film and the aforementioned reflective sheet. The in-mold film may be an in mold decoration (IMD) film or an in mold label film (IML film). The IMD (in mold decoration) is a technology that inserts a film with a printed pattern laminated into the mold when injection molding a plastic product, etc., and transfers the printed pattern to the surface of the plastic product, etc. within the mold at the same time as injection molding. means, and the IMD film refers to a film used in IMD. The IMD film may be composed of a base release film, hard coating layer 1 laminated on the base release film, a printing layer laminated on the hard coating layer 1, and an adhesive layer laminated on the printing layer. The IMD can be used interchangeably with IMT (In Mold Transcription).

In some embodiments, the degree of protrusion of the in-mold injection product may vary depending on the region. For example, the degree of protrusion of the portion corresponding to the first region of the printed layer and the portion corresponding to the second region of the printed layer may be different. Through this, it is possible to check the part where the RFID pattern is formed to the degree of protrusion.

The IML (in mold label) refers to a technology of molding a plastic film using a vacuum forming or press process, removing unnecessary parts, inserting it into an injection mold, and then injecting the finished product. The IML film is used for IML. It means a film that becomes The IML film may be composed of a protective film, a hard coating layer 1 laminated on the protective film, a base film laminated on the hard coating layer 1, a printed layer laminated on the base film, and an adhesive layer laminated on the printed layer.

The in-mold film is prepared as an IMD film or an IML film depending on the processing method, and the retroreflective sheet is prepared by laminating a reflective layer, a focusing resin layer, a refractive lens layer, a refractive lens adhesive layer, and a surface film layer on the hard coating layer 2.

The retroreflective sheet refers to a sheet with a reflection phenomenon in which a radiation source reflects in the incident direction and returns over a wide range of incident directions, and may be formed by including glass beads or microprisms.

The base release film serves to protect the hard coating layer 1 before hardening during the IMD injection and molding process. The base release film is a group consisting of polyester, polyamide, polystyrene, polymethyl methacrylate, polyurethane, and polyvinyl chloride (PVC). It may be formed from a material selected from . The base release film may have a thickness of 30 to 50 μm.

The protective film serves to protect the hard coating layer 1 during the IML injection and molding process. The protective film may be made of a material selected from the group consisting of polyester, polyurethane, and polyvinyl chloride (PVC).

Hard coating layer 1 and hard coating layer 2 serve to prevent damage to the printing layer and reflective layer, respectively, and are made of at least one from the group consisting of silsesquioxane, acrylate, methacrylate, epoxy, urethane, silicone, and melamine resin. It may include The hard coating layer may have a thickness of 30 to 60㎛.

The base film prevents damage to the printed layer and allows various texture expressions by adding patterns.

The printed layer is a layer in which the pattern that appears on the surface of the injection molded product is formed by printing, and is made of a material selected from the group consisting of polyethylene terephthalate, polycarbonate, and polyvinyl chloride (PVC). It may be possible. The printed layer may have a thickness of 40 to 60 μm. The printing layer may further include one or more layers selected from a UV pattern layer, a multi-deposition layer, and a screen color printing layer.

The adhesive layer serves to bond the printing layer and the surface film layer, and may include urethane or urethane-acrylic adhesive resin as a material. The adhesive layer may have a thickness of 40 to 60 μm.

The reflective layer may be formed using metal deposition, for example. Aluminum, silver, etc. can be used as the metal. Alternatively, the reflective layer may comprise a multilayer reflective coating disposed on the microspheres, such as described in U.S. Pat. No. 6,243,201 to Fleming, for example. The thickness of the reflective layer may be about 10 to about 60 μm. When visible light enters the retroreflector from the normal direction, the visible light passes through the refractive lens, is reflected by the reflective layer, and is redirected toward the light emitting source. When infrared light is incident on a retroreflector from a large angle of incidence (e.g., an angle of incidence displaced from near the normal), the infrared light passes through the refractive lens, and at least a portion of the infrared light is absorbed and/or scattered by the infrared blocking layer. do. In this way, retroreflection of infrared light is reduced or suppressed.

Next, a mixed sheet is produced by bonding the adhesive layer of the in-mold film and the surface film layer of the above-described reflective sheet.

The method of bonding the in-mold film and the retroreflective sheet may use a roll to roll method, but is not limited thereto.

The mixed sheet manufacturing step may further include the step of surface treatment with a primer, corona, or plasma to improve adhesion between the hard coating layer 2 and the injection material.

Next, the mixed sheet is mounted in an injection mold and deformed to fit the inner surface of the mold.

The mixing sheet is arranged according to the shape of the mold, and the hard coating layer of the mixing sheet is cured by irradiating UV to prevent deformation of the mixing sheet when injection material is injected.

Next, the molten injection material is injection-injected into the cavity of the mold.

Injection injection means forming a cavity by closing the mold, and injecting the molten injection material into the cavity so that the molten injection material is directly discharged at the injection point.

The injection material may be resin or ceramic.

Next, the molten injection material is cured to form an injection molded product in which the mixed sheet and the cured injection material are bonded.

Hardening of the molten injection material may be performed by cooling the injection mold in the closed state.

Next, the hard coating layer 1 of the mixed sheet adhered to the injection molded product is cured.

After taking out the cured product from the injection mold, UV is irradiated to the entire hard coating layer 1 of the mixed sheet using a large ultraviolet lamp to cure the entire area.

Finally, the cured injection molded product is separated from the mold to obtain a retroreflective in-mold injection product.

When the in-mold injection product is a product obtained using an IMD film, a step of separating the base release film from the hard coating layer 1 may be additionally included.

Hereinafter, the configuration of the present invention and its effects will be described in more detail through specific examples and comparative examples. However, these examples are for illustrating the present invention in more detail, and the scope of the present invention is not limited to these examples.

410: Base film layer
420: Hard coating
500: Printing layer
510: UV pattern printing layer
520: Metal thin film layer
530: Screen color printing layer
430: Wireless recognition resin film layer
431: Resin film
432: Antenna
433: RFID chip
434: Protective resin film
440: Resin film adhesive layer
600: Recursive reflection unit
610: Point, adhesive layer
620: Refractive lens adhesive layer
630: Refractive lens layer
631: Infrared blocking thin film
640: focal resin layer
650: reflective layer
660: Infrared reflective layer
710: Adhesive

Claims (6)

adhesive (710);
A reflective layer 650 formed on top of the adhesive and reflecting incident light in the visible light range;
a focusing resin layer 640 formed on the top of the reflective layer to focus incident light at the interface with the reflective layer;
A refractive lens layer 630 that is attached and formed on the focusing resin layer to retroreflect light in the visible region, wherein the refractive lens layer includes a plurality of glass beads or microprisms, and the plurality of bead-shaped lenses Alternatively, one or more infrared blocking thin films 631 are formed on the upper surface of the prism-shaped lens, and the infrared blocking thin films are SiO ₂ , MB ₂ O ₅ , TiO ₂ , ZnS, ZnO, Al ₂ O ₃ , ZrO ₂ , Ta A refractive lens layer deposited with one or more materials selected from ₂ O ₅ , Nb ₂ O ₅ , CaF ₂ and Na ₃ AlF ₆ ;
a refractive lens adhesive layer 620 that enables the surface film layer to be adhered to the refractive lens layer;
It is formed on top of the refractive lens adhesive layer, and is selected from SiO ₂ , MB ₂ O ₅ , TiO ₂ , ZnS, ZnO, Al ₂ O ₃ , ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , CaF ₂ and Na ₃ AlF ₆ an infrared reflecting layer 660 formed by depositing or coating with one or more selected materials;
An adhesive layer 610 formed on the top of the refractive lens adhesive layer to prevent the refractive lens layer from being damaged;
A resin film 431 formed on the top of the adhesive layer, an antenna 432 on which a circuit is formed and printed on the resin film 431 through conductive ink, high-temperature deposition, or metal foil etching, and an RFID chip connected to the antenna. (433), a wireless recognition resin film layer (430) made of a protective resin film (434) that protects the antenna and the RFID chip;
A printing layer 500 laminated on the wireless recognition resin film layer 430, and a resin film adhesive layer 440 that enables the wireless recognition resin film layer 430 and the printing layer 500 to be bonded. And, the print layer includes a metal thin film layer 520 formed on the top of the resin film adhesive layer, a UV pattern print layer 510 formed on the top of the metal thin film layer, and a screen color print layer 530;
It includes a hard coating 420 formed on top of the metal thin film layer, and a base film layer 410 formed on top of the hard coating 420,
The metal thin film layer 520 is printed with a coating solution containing metal oxide particles, and the metal oxide particles are SiO ₂ , TiO ₂ , ZnS, ZnO, Al ₂ O ₃ , ZrO ₂ , Ta ₂ O ₅ , and Nb ₂ O ₅ , deposited with any one material selected from CaF ₂ and Na ₃ AlF ₆ ,
The printed layer includes a first area vertically corresponding to the area where the antenna 432 is located within the wireless recognition resin film layer, and a second area excluding the first area,
A retroreflective sheet capable of wireless recognition in which the first and second regions of the printed layer have different reflected visible light wavelengths. According to paragraph 1,
A retroreflective sheet capable of wireless recognition, which additionally includes an electromagnetic wave shielding layer formed at the bottom of the external adhesive layer to prevent RFID chip errors caused by electromagnetic waves emitted from the vehicle. An in-mold film preparation step of preparing an in-mold film including a hard coating layer 1, a printing layer, and an adhesive layer;
Hard coating layer 2, preparing a retroreflective sheet capable of wireless recognition according to claim 1 formed on top of the hard coating layer 2;
A mixed sheet manufacturing step of manufacturing a mixed sheet by bonding the adhesive layer of the in-mold film and the surface film layer of the retroreflective sheet;
A mixed sheet mounting step of mounting the mixed sheet on an injection mold;
A mixing sheet deformation step of bending the mixing sheet to contact the inner surface of the mold;
An injection material injection step of injecting molten injection material into the cavity of the mold;
an injection material curing step of curing the molten injection material to form an injection molded product in which the mixed sheet and the cured injection material are bonded;
A curing step of curing the hard coating layer 1 of the mixed sheet adhered to the injection molded product; and
A product extraction step of separating the cured injection molded product from the mold; A method of manufacturing a retroreflective in-mold injection molded product comprising a.
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