JP2011095444A - Hologram sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new hologram sheet which performs the reproduction of hologram having a wavelength different from that of illumination light, unlike the hologram reproducing a hologram reproduction image having the same wavelength as that of the illumination light in order to improve the authenticity, in the hologram sheet using hologram. <P>SOLUTION: A novel discrimination method is provided by disposing a fluorescent layer on a hologram formation layer, illuminating a fluorescent body with exciting light and making a hologram reproduction image formed by virtue of fluorescence emission in the visual light region discriminable by visual observation. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a novel hologram sheet, and more particularly to a fluorescent light emitting hologram sheet in which a fluorescent light emitter is disposed at a relief position of a relief hologram that exhibits a phase hologram.
In the present specification, “part” indicating the formulation is based on mass. The “hologram” includes a hologram and a hologram having a light diffractive function such as a diffraction grating.

(Main applications)
The main use of the hologram sheet of the present invention is in the art / craft field and commercial field using the hologram itself for decoration, but is not limited to this, and is a hologram sheet used in the counterfeit prevention field. In particular, credit cards and other counterfeited products that can damage cardholders and card companies, driver's licenses, employee ID cards, ID cards such as membership cards, and entrance examinations For tickets, passports, banknotes, gift certificates, point cards, stock certificates, securities, lottery tickets, horse tickets, bank passbooks, boarding tickets, toll tickets, air tickets, tickets for various events, play tickets, transportation and public telephones There are prepaid cards.
Each of these is an information recording body that holds information having economic or social value, and it is desirable to have a function that can identify the authenticity of the recording body for the purpose of preventing damage caused by forgery. .

In addition to these information recording media, expensive products such as luxury watches, luxury leather products, precious metal products, jewelry, etc., often referred to as luxury brand products, or storage of such expensive products. Boxes and cases can also be forged. In addition, mass-produced products of famous brands, such as audio products, electrical appliances, etc., or tags that are hung on them are also subject to forgery.
Furthermore, a storage body in which music software, video software, computer software, game software, or the like, which is a copyrighted work, or cases thereof can also be forged. In addition, it is desirable that products such as printer toner, paper, and the like in which supplies to be replaced are limited to genuine materials have a function of identifying their authenticity for the purpose of preventing damage caused by forgery.

(Background technology)
Conventionally, for the purpose of preventing counterfeiting of information recording bodies and various articles described above (collectively referred to as authenticity identification objects), it is said that they have manufacturing difficulties due to the precision of their structures. In many cases, holograms are applied as authenticity distinguishable. However, since the hologram manufacturing method itself is known and can be precisely processed by that method, when the hologram is merely for visual judgment, there is no difference between a genuine hologram and a forged hologram. It is difficult to distinguish.
These authentic identification objects, in particular, articles that have been subjected to hologram images in a label form or transfer form, are not only used for authentic identification of visual confirmation of hologram images, but also by using a new authenticity identification method. There is a need to identify the authenticity of.

(Prior art)
In order to meet these requirements, there has been proposed a hologram sheet having a light selective reflection layer that is laminated on a hologram and reflects only one of the left-handed polarized light and the right-handed polarized light among the incident light. (For example, refer to Patent Document 1.)
As this light selective reflection layer, cholesteric liquid crystal is used, and the anti-counterfeiting property is enhanced by a method of confirming using a polarizing plate or the like.
However, as described in Patent Document 1, since the reflectance of the reflective thin film layer on the hologram forming layer is high, the light that is transmitted without being reflected by the cholesteric liquid crystal layer (complementary light of selective reflected light) Reflecting on the reflective thin film layer and returning to the cholesteric liquid crystal layer again (hereinafter referred to as return light), this return light becomes a noise component when observing the cholesteric liquid crystal and is added to and mixed with the selectively reflected light. However, the color tone was not the original color of the liquid crystal, and it was even difficult to see and identify.

In addition, the cholesteric liquid crystal material itself is expensive, and in order to bring out the liquid crystal performance, it is indispensable to form an alignment film in contact with the liquid crystal layer. Furthermore, due to the light scattering property of the cholesteric liquid crystal, the hologram There have been problems such as blurring and distortion of the image when light for reproducing the image passes through the liquid crystal layer.
For this reason, it has been devised to suppress the light scattering property of the cholesteric liquid crystal layer or to make the cholesteric liquid crystal layer itself thin. However, in order to suppress the light scattering property of the cholesteric liquid crystal layer, the refractive index difference is reduced, When the liquid crystal layer is made thin, the function as the light selective reflection layer described above is deteriorated, and it has a drawback that it is difficult to obtain optimum conditions for ensuring the clarity and anti-counterfeit performance of the hologram image. .

JP 2007-90538 A

  Accordingly, the present invention has been made to solve such problems. The purpose is to provide a hologram forming layer of a phase hologram, that is, a fluorescent layer so as to be in contact with the hologram relief, or a fluorescent layer is partially formed in synchronization with the hologram relief to illuminate a light source having a predetermined wavelength. It is an object of the present invention to provide a novel hologram sheet in which a hologram can be visually recognized only under such a condition, and the illumination light source and the reproduced hologram have different color tones. Furthermore, since such a hologram sheet has not existed so far, it is to provide a novel decorative property and an anti-counterfeit property to which this is applied.

To solve the above problem,
The first aspect of the hologram sheet of the present invention is:
A transparent resin layer having a hologram relief including a diffraction grating group corresponding to a hologram image is provided on one surface of the transparent substrate, and a fluorescent layer is provided in contact with the hologram relief, and further on the transparent resin A transparent resin layer having a refractive index difference with the layer of 0.3 or less is provided.
According to the hologram sheet of the first aspect,
A transparent resin layer having a hologram relief including a diffraction grating group corresponding to a hologram image is provided on one surface of the transparent substrate, and a fluorescent layer is provided in contact with the hologram relief, and further on the transparent resin It is possible to provide a hologram sheet provided with a transparent resin layer having a refractive index difference with the layer of 0.3 or less.
The second aspect of the hologram sheet of the present invention is:
The fluorescent layer is formed with a uniform thickness following the unevenness forming the hologram relief, and a transparent resin layer having a refractive index difference with the transparent resin layer within 0.3 is provided thereon. It is characterized by being.
According to the hologram sheet of the second aspect,
The fluorescent layer is formed with a uniform thickness following the unevenness forming the hologram relief, and a transparent resin layer having a refractive index difference with the transparent resin layer within 0.3 is provided thereon. A hologram sheet can be provided.
A diffraction grating group for reproducing a hologram image is formed as a hologram relief on the surface of the transparent resin layer as a substantially flat surface, and a fluorescent layer is provided on the relief or with a uniform thickness following the relief. Furthermore, a transparent resin layer having a difference in refractive index from the transparent resin layer within 0.3 is provided thereon.
That is, the hologram relief shows the phase difference as a phase hologram in a relief shape, but the fluorescence emitted from the fluorescence layer is generated by providing a fluorescent layer following (along) the relief shape having this phase difference. The light is emitted with (including) the above phase difference.
Further, on the fluorescent layer, a second transparent resin layer (with a refractive index difference of 0.3 or less with respect to the refractive index of the transparent resin layer having a hologram relief (hereinafter also referred to as a first transparent resin layer)). (Hereinafter also referred to as a second transparent resin layer)), the effect that light incident on the first transparent resin layer is emitted at substantially the same angle from the second transparent resin layer is produced, and the hologram sheet is transparent. (The effect that incident light is emitted almost as it is).
Furthermore, if the refractive index of the fluorescent layer has a similar value, reflection and refraction at the interface of each layer inside the hologram sheet can be suppressed, and the transparency of the hologram sheet is further improved.

In the case of the hologram sheet of the present invention, the Huygens secondary wave generated when reproducing the relief hologram is equivalent to this secondary wave, which is a phosphor (or fluorescent substance) disposed on the hologram relief surface. This light emission plays a role, and the emitted light is observed including the phase difference of the hologram relief including the diffraction grating group corresponding to the hologram image. It is emitted to the person side.
This emitted light causes an interference phenomenon in the space on the hologram relief surface, and as a result, a predetermined hologram reproduction image appears in a predetermined direction.
A phosphor is a substance that absorbs energy such as ultraviolet rays, electron beams, and X-rays and emits it as visible light. For example, a material obtained by adding a trace amount of metal ions responsible for light emission such as Eu and Ce to a base ceramic crystal. Etc. In this case, metal ions that contribute to light emission are excited by absorbing energy applied from the outside (energy such as ultraviolet rays, electron beams, X-rays, of course, visible rays, infrared rays, etc.), and then the ground state. Lights when returning to. The lattice of the host crystal functions to chemically stabilize the ions by surrounding the metal ions, and to control the emission color and intensity by adjusting the crystal field and coordination environment.
The present invention uses a phosphor material that emits light in the visible light region by Stokes shift among these fluorescent emissions. Of course, a material that emits light in the visible light region due to infrared excitation can also be used.

The present invention reproduces a hologram at a wavelength different from the wavelength of the illumination light source of the hologram, for example, it can be illuminated with ultraviolet light and a green hologram can be visually recognized. In the absence of the normally used green illumination light source, only the hologram shines, appears to float in the air, and is excellent in design.
Furthermore, the phenomenon that a large amount of ultraviolet light is reflected on the surface of the fluorescent layer, that is, the interface between the fluorescent layer and the air layer, which occurs in the absence of the second transparent resin layer, causes the phenomenon that ultraviolet rays are radiated to the viewer side. By providing a transparent resin layer, it can be significantly suppressed. This is because the refractive index of the first transparent resin layer, for example, n = 1.5, and the refractive index of air is 1.0, so a large reflection occurs due to the difference in refractive index. In other words, by providing a second transparent resin layer having a refractive index difference within 0.3, this unnecessary reflection can be suppressed. It is also preferable to mix the second transparent resin layer with an ultraviolet absorber so as to directly absorb ultraviolet rays because the effect is increased.
The hologram sheet of the present invention is capable of reproducing a hologram only for those who know the specific wavelength range because the wavelength range of a light source capable of reproducing the hologram is very narrow. It will be useful. Also, only those who can know the value of the Stokes shift described above can predict the color tone of the hologram reproduction image, and only the hologram that can pass through the bandpass filter by looking through the bandpass filter adjusted to the reproduction wavelength is authentic. It can also be determined.
Further, the angle (diffraction angle) passing through the bandpass filter also depends on the amount of Stokes shift, and only those who can know the value can make the determination at the predetermined angle.
Furthermore, by including a plurality of phosphors, this reproduced image appears in different colors at a plurality of angles, which is superior both in terms of design and authenticity.
As shown in the Jablonsky diagram shown in FIG. 1, the principle of fluorescence emission is first determined by light absorption from the ground state (S0: singlet state) of the phosphor (including fluorescent dye, fluorescent pigment, fluorescent dye, etc.). The luminescent material excited in any one of the vibration states (S1), second (S2), third excited state (S3),... Or a triplet state (T1, T2) by intersystem crossing. The phosphor in the lowest vibration state of S1 returns to the ground state due to a non-radiation process or emits fluorescence. The molecule in the triplet state returns to the ground state by a non-radiative process or phosphorescence.

Since the transition between singlets occurs instantaneously, the half-life of fluorescence is as short as 10 ⁻⁴ sec or less. The time required for the transition is said to be excited at 10 ⁻¹⁵ sec and then to emit fluorescence at 10 ⁻⁹ to 10 ⁻⁷ sec.
On the other hand, the transition from triplet to singlet is forbidden due to the prohibition of spin change, and spontaneous emission is difficult to occur.
Whether or not light is emitted when returning to the ground state, whether the intensity of light is strong or weak, and whether the fluorescence lifetime is long or short largely depends on the molecular structure of the phosphor material and the environment in which the molecule is placed.
The wavelength distribution of the emitted light of the phosphor material is called a fluorescence spectrum, and the fluorescence spectrum is created by plotting the fluorescence intensity relative to the fluorescence wavelength. (In actual fluorescence spectrum measurement, excitation light with a constant wavelength and intensity is used as the light source, and when dealing with phosphors, the emission spectrum is called the fluorescence spectrum.) The wavelength (energy) shown in the fluorescence spectrum ) Is equal to the energy difference from the lowest vibration energy level in the primary excited state to the preferential vibration energy level in the ground state.
If the amplitude of the fluorescence is similar to the amplitude structure of the excited state and the ground state, the wavelength of the light energy absorbed by the fluorescent dye and the wavelength emitted as fluorescence are theoretically related to the amplitude of the excitation on the longest wavelength side. Will be the same. However, in practice, the fluorescence spectrum of most fluorescent dyes shifts to the longer wavelength (low energy) side. The difference between the peak wavelengths of the excitation spectrum and the fluorescence spectrum is called the Stokes shift, and this wavelength difference is caused by the energy released in the excited state before the emission of fluorescence being converted into thermal energy.

The Stokes shift is very important in the sensitivity of fluorescence, and when detecting fluorescence, the background can be lowered because it is not affected by excitation light.
When the wavelength and intensity of incident light are constant (for example, when controlled laser light is used as a light source), the emitted fluorescence is directly proportional to the amount of fluorescent material. Therefore, in order to make the fluorescence intensity constant, it is necessary to make the amount of the phosphor in the fluorescent layer formed on the hologram relief surface constant. Of course, when the concentration of the phosphor is high, saturation occurs and the linearity is lost, resulting in a constant intensity, or the distance between the phosphors is very close, and only the vicinity of the surface is excited and the emitted fluorescence is absorbed. Therefore, in order to sufficiently obtain the coherence of fluorescent light, which is the object of the present invention, it exists uniformly only in the vicinity of the hologram relief surface, rather than a large amount of phosphors dispersed in the thickness direction of the fluorescent layer. In order to produce a higher interference phenomenon, it is desirable that the particle size is 1 to 10 times, more preferably 1 to 3 times the particle size of the phosphor. When the phosphor is a dye and is dissolved in the resin forming the fluorescent layer, it is necessary to keep the resin layer thin. When dyeing with a fluorescent dye, the above-mentioned object can be achieved by dyeing only the relief surface of the transparent resin layer itself forming the hologram relief.

Also, depending on the phosphor, the emitted fluorescence intensity (brightness) varies, and the fluorescence intensity directly affects the sensitivity, so the fluorescence intensity of the phosphor is a very important factor. The fluorescence intensity depends on the following two characteristics of the phosphor:
・ Light absorption efficiency (absorption coefficient)
-Conversion efficiency between excitation light and fluorescence (quantum yield)
Since the fluorescence intensity is proportional to the extinction coefficient (ε) and quantum yield (φ) of the phosphor, it is expressed by the following equation.
・ Fluorescence intensity (luminance) 吸 光 Absorption coefficient (ε) × quantum yield (φ)
Here, the extinction coefficient of the phosphor means the amount of light of a specific wavelength absorbed by the phosphor, and the molar extinction coefficient is defined as the optical density of a 1M (1 mol) fluorescent dye solution per 1 cm of the optical path. Useful phosphors have a molar extinction coefficient of 10,000 or more. The conversion efficiency (quantum yield) between excitation light and fluorescence can be obtained from the following equation.
Φ = number of emitted photons / number of absorbed photons Here, the quantum yield (φ) ranges from “0” (non-fluorescent substance) to “1” (efficiency 100%). Examples showing the quantum yield of the phosphor include fluorescein (φ = 0.9) and Cy5 (φ = 0.3). The peak wavelength of the absorption spectrum is used for the usual quantum yield (φ) measurement.

Fluorescein (ε = 70,000, φ = 0.9) and Cy5 (ε = 200,000, φ = 0.3) have extremely high luminance, and these phosphors have quantum yields and extinction coefficients. Although very different, the fluorescence intensity is equivalent.
Therefore, when evaluating a phosphor, it is necessary to consider both the extinction coefficient and the quantum yield. Fluorescence intensity is also affected by the intensity of incident light. Theoretically, when the amount of incident light is increased, the number of excited phosphors increases, and the amount of emitted light (the number of photons or the ground state falls to the ground state) Number) increases and is observed as an increase in fluorescence intensity. However, in reality, if the incident light intensity is increased too much, all the phosphors are always excited, causing fluorescence destruction, resulting in attenuation or disappearance of the fluorescence intensity and loss of correlation with the fluorescence intensity. Therefore, it is necessary to appropriately determine the amount of incident light.
In addition, the quantum yield, excitation spectrum, and fluorescence spectrum of the phosphor are determined based on environmental conditions, that is, environmental temperature, ion concentration, pH, excitation light intensity, covalent bond with resin, non-covalent interaction (intercalation The optical filter (low-pass filter, high-pass filter, band-pass filter, etc.) that makes it easy to recognize the excitation light wavelength and fluorescent light in consideration of these environmental conditions. May need to be set as needed.

Another environmental effect is photobleaching with light. Since the phosphor in the excited state is chemically activated as compared with the ground state, it is more likely to be destroyed and, for example, the “excited fluorescent dye molecule” proceeds with a chemical reaction, but is less frequent. May have a low fluorescence structure. The progress of this chemical reaction depends on the sensitivity of individual phosphors to photobleaching and the chemical environment, the intensity of excitation light, the irradiation time of excitation light, the number of repetitions of optical scans for observation and authentication, etc. Settings according to the purpose are required.
When the wavelength and intensity of incident light are made constant, such as when a controllable laser beam is used as the light source, the emitted fluorescence (number of photons) is directly proportional to the amount of phosphor. If the phosphor is at a very high concentration, the signal response is non-linear.
The number of photons emitted from a certain amount of phosphor can be amplified by repeating the excitation / emission cycle. When the excitation light intensity and the phosphor concentration are constant, the total amount of emitted light is proportional to the irradiation time (period in which excitation light is irradiated to a fluorescent dye or the like). If the irradiation time is longer than the time of the excitation / emission cycle, the phosphor repeats the excitation / emission cycle many times. The fluorescence intensity (number of emitted photons) can be measured by any light receiving element.
When measuring low-intensity light, a photomultiplier tube (PMT) having an amplification mechanism is effective. When light having sufficient energy enters the PMT, electrons are emitted from the cathode, and the electrons are amplified as a current. The currents of these light receiving elements are proportional to the intensity of incident light, and the fluorescence intensity is usually displayed in arbitrary units (eg, rfu: relative-fluorescence units).

The phosphor is generally manufactured by a solid phase reaction method in which a phosphor material is fired. In this solid phase reaction method, since the raw material mixture is fired at a high temperature, the obtained fired cake is often a product in which phosphor particles are hard and aggregated. Therefore, normally, when manufacturing the phosphor, for example, a pulverization process using a ball mill, a mortar, etc., is performed. Substantially monodispersed phosphor-precursor particles are suspended in a flowing gas and baked to produce substantially monodispersed fluorescent particles that are not aggregated. According to this method, fluorescent particles having a size of less than 1 μm can be produced.
In addition, for example, when manufacturing a ZnGa2O4: Mn phosphor, the phosphor raw material before firing is prepared by a wet precipitation method, which enables firing at a low temperature and suppresses aggregation of the phosphor particles. it can.
Further, for example, regarding a method for producing a phosphor having an alkaline earth aluminate-based or alkaline earth silicate-based host crystal, strontium nitrate is used as a phosphor raw material containing Sr, and a raw material mixture or suspension There is a method of forming droplets so as to have a desired particle diameter and firing the droplets. Thereby, a phosphor having extremely brittle properties can be obtained, and can be easily pulverized to a minute size.

As the phosphor material, a compound containing an element constituting the phosphor to be manufactured (hereinafter also referred to as “phosphor constituent element”) can be used. Examples thereof include oxides, hydroxides, carbonates, nitrates, sulfates, oxalates, carboxylates, halides, nitrides and the like containing phosphor constituent elements. When selecting the phosphor raw material, it is preferable to select in consideration of the reactivity to the obtained phosphor. Furthermore, corresponding to each phosphor constituting element constituting the phosphor, one kind of phosphor raw material may be used, or two or more kinds may be used in combination in any combination and ratio.
Further, the impurities contained in each phosphor raw material of the phosphor are not particularly limited as long as the phosphor characteristics are not adversely affected.
The weight median diameter of each phosphor material is usually 0.01 μm or more and 0.5 μm or less. For this reason, depending on the type of the phosphor material, pulverization may be performed in advance by a dry pulverizer such as a jet mill. As a result, each phosphor raw material can be uniformly dispersed in the raw material mixture, and the solid phase reactivity of the raw material mixture can be increased by increasing the surface area of the phosphor raw material, thereby suppressing the generation of impurity phases. It becomes.

For example, specific examples of phosphor raw materials containing Ba include BaO, Ba (OH) 2 .8H 2 O, BaCO 3, Ba (NO 3) 2, BaSO 4, Ba (C 2 O 4) · 2H 2 O, Ba (OCOCH 3) 2 and BaCl 2. Can be mentioned.
Specific examples of phosphor materials containing Ca include CaO, Ca (OH) 2, CaCO3, Ca (NO3) 2 · 4H2O, CaSO4 · 2H2O, Ca (C2O4) · H2O, Ca (OCOCH3) 2 · H2O, anhydrous And CaCl2 (however, it may be a hydrate).
Specific examples of the phosphor raw material containing Sr include SrO, Sr (OH) 2 · 8H2O, SrCO3, Sr (NO3) 2, SrSO4, Sr (C2O4) · H2O, Sr (OCOCH3) 2 · 0.5H2O, SrCl2 Etc.
Specific examples of the phosphor material containing Zn include ZnO, Zn (C2O4) .2H2O, ZnSO4.7H2O, and the like.
Specific examples of the phosphor raw material containing Mg include MgCO3, MgO, MgSO4, Mg (C2O4) .2H2O, and the like.
Specific examples of the phosphor material containing Si include SiO2, H4SiO4, Si (OCOCH3) 4, and the like.
Specific examples of the phosphor material containing Eu include Eu2O3, Eu2 (SO4) 3, Eu2 (C2O4) 3, EuCl2, EuCl3, Eu (NO3) 3 · 6H2O.
Specific examples of each phosphor raw material containing Sm, Tm, and Yb include compounds in which Eu is replaced with Sm, Tm, and Yb, respectively, in the compounds listed as specific examples of the Eu source.

Specific examples of the phosphor raw material containing Mn include MnO, MnO2, Mn2O3, MnF2, MnCl2, MnBr2, Mn (NO3) 2 · 6H2O, MnCO3, MnCr2O4 and the like.
Specific examples of the phosphor material containing Cr include Cr2O3, CrF3 (may be a hydrate), CrCl3, CrBr3 · 6H2O, Cr (NO3) 2 · 9H2O, (NH4) 2CrO4, and the like.
Specific examples of phosphor materials containing Tb include Tb4O7, TbCl3 (including hydrates), TbF3, Tb (NO3) 3 · nH2O, Tb2 (SiO4) 3, Tb2 (C2O4) 3 · 10H2O, and the like. It is done. Further, other phosphor materials (for example, Eu source) and Tb source may be co-precipitated before use.
Specific examples of the phosphor material containing Pr include Pr2O3, PrCl3, PrF3, Pr (NO3) 3 · 6H2O, Pr2 (SiO4) 3, Pr2 (C2O4) 3 · 10H2O, and the like.
Specific examples of the phosphor raw material containing Ce include CeO2, CeCl3, Ce2 (CO3) 3 · 5H2O, CeF3, Ce (NO3) 3 · 6H2O, and the like.
Specific examples of the phosphor material containing Lu include Lu2O3, LuCl3, LuF3 (may be a hydrate), Lu (NO3) 3 (may be a hydrate), and the like.
Specific examples of the phosphor material containing La include La2O3, LaCl3 · 7H2O, La2 (CO3) 3 · H2O, LaF3, La (NO3) 3 · 6H2O, La2 (SO4) 3, and the like.
Specific examples of the phosphor material containing Gd include Gd2O3, GdCl3 · 6H2O, Gd (NO3) 3 · 5H2O, Gd2 (SO4) 3 · 8H2O, GdF3 and the like.

Specific examples of the phosphor material containing Ge include GeO2, Ge (OH) 4, Ge (OCOCH3) 4, and GeCl4.
Specific examples of the phosphor material containing Ga include Ga2O3, Ga (OH) 3, Ga (NO3) 3.nH2O, Ga2 (SO4) 3, and GaCl3.
Specific examples of the phosphor material containing Al include Al2O3 such as α-Al2O3 and γ-Al2O3, Al (OH) 3, AlOOH, Al (NO3) 3 · 9H2O, Al2 (SO4) 3, and AlCl3.
Specific examples of the phosphor raw material containing P include P2O5, Ba3 (PO4) 2, Sr3 (PO4) 2, (NH4) 3PO4 and the like.
Specific examples of the phosphor material containing B include B2O3 and H3BO3.
In addition, you may use the raw material illustrated above, after coprecipitating as needed.
Further, phosphor raw materials corresponding to N element, O element, halogen element, etc. are usually manufactured as phosphors as anion components of the phosphor raw materials of the respective phosphor constituting elements or as components contained in the firing atmosphere. Sometimes supplied.

After preparing a raw material mixture by mixing phosphor raw materials, the raw material mixture is fired at a predetermined temperature and atmosphere. At this time, it is preferable to perform the mixing sufficiently.
Although it does not specifically limit as said mixing method, Specifically, the method quoted as the following (A) and (B) can be used. As for these various conditions, for example, it is possible to select conditions such as mixing and using two kinds of balls having different particle diameters in a ball mill.
(A) Dry pulverizer such as hammer mill, roll mill, ball mill, jet mill, etc., or pulverization using mortar and pestle, and mixer such as ribbon blender, V-type blender, Henschel mixer, or mortar and pestle And a dry mixing method in which the above phosphor raw materials are pulverized and mixed.
(B) Add a solvent or dispersion medium such as an alcohol solvent such as methanol or ethanol or water to the phosphor raw material, and mix using, for example, a pulverizer, a mortar and pestle, or an evaporating dish and a stirring bar, A wet mixing method in which a solution or slurry is made and then dried by spray drying, heat drying, or natural drying.
The mixing of the phosphor raw material can be either wet or dry depending on the physical properties of the phosphor raw material.
In addition, when using a material that easily oxidizes and absorbs moisture, such as halide and nitride, for example, an inert gas such as argon gas or nitrogen gas is filled and mixed in a glove box in which moisture is controlled.

In addition, the phosphor material may be sieved for the purpose of, for example, uniforming the particle size during mixing and pulverization. In this case, various types of commercially available sieves can be used, but it is preferable to use a resin mesh such as a nylon mesh rather than a metal mesh in terms of preventing impurities from being mixed.
In the firing step, a fired product is obtained by firing the obtained raw material mixture. The obtained fired product usually has the composition of the intended phosphor, but the particles are sintered into a fired cake.
Furthermore, when the number of heat-resistant containers in the baking furnace is large in baking, for example, the rate of heat transfer to each heat-resistant container can be made uniform, for example, by slowing the temperature increase rate. It is preferable for firing without any problems.
The firing conditions such as the firing temperature, pressure, and atmosphere in the firing step are preferably set appropriately for each phosphor to be manufactured.
Furthermore, in order to further improve the weather resistance such as moisture resistance or to improve the dispersibility of the phosphor in the phosphor-containing part of the light emitting device, the surface of the phosphor is coated with a different substance as necessary. You may perform surface treatments, such as.

Examples of substances that can be present on the surface of the phosphor (hereinafter also referred to as “surface treatment substances”) include organic compounds, inorganic compounds, glass materials, and the like. Examples of the organic compound include acrylic resins, heat-meltable polymers such as polycarbonate, polyamide, and polyethylene, latex, polyorganosiloxane, and the like.
Examples of inorganic compounds include magnesium oxide, aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, tin oxide, germanium oxide, tantalum oxide, niobium oxide, vanadium oxide, boron oxide, antimony oxide, zinc oxide, yttrium oxide, oxide Examples thereof include metal oxides such as lanthanum and bismuth oxide, metal nitrides such as silicon nitride and aluminum nitride, orthophosphates such as calcium phosphate, barium phosphate, and strontium phosphate, and polyphosphates. And at least one selected from the group consisting of lithium phosphate, sodium phosphate, and potassium phosphate, and at least one selected from the group consisting of barium nitrate, calcium nitrate, strontium nitrate, barium hydrochloride, calcium hydrochloride, and strontium hydrochloride. Can also be used in combination. Among them, it is preferable to use a combination of sodium phosphate and calcium nitrate. Further, when barium, calcium, or strontium is present on the phosphor surface, the surface treatment can be performed using only a phosphate such as sodium phosphate.

Examples of the glass material include borosilicate, phosphosilicate, and alkali silicate. Any one of these surface treatment substances may be used alone, or two or more thereof may be used in any combination and ratio.
The phosphor subjected to the surface treatment has these surface treatment substances. Examples of the presence of the surface treatment substance include the following.
(I) A mode in which the surface treatment substance constitutes a continuous film and covers the surface of the phosphor.
(Ii) An embodiment in which the surface of the phosphor is coated by the surface treatment substance becoming a large number of fine particles and adhering to the surface of the phosphor.
The adhesion amount or the coating amount of the surface treatment substance on the surface of the phosphor is 0.1% by weight or more, 30% by weight or less, preferably 15% by weight or less based on the weight of the phosphor. desirable. If the amount of the surface treatment substance relative to the phosphor is too large, the light emission characteristics of the phosphor may be impaired. If the amount is too small, the surface coating will be incomplete, and the moisture resistance and dispersibility will not be improved. There is.
The surface treatment method is not particularly limited. For example, a metal oxide (described below)
And a coating treatment method using silicon oxide).

The phosphor is mixed in an alcohol such as ethanol and stirred, and further an alkaline aqueous solution such as ammonia water is mixed and stirred. Next, a hydrolyzable alkyl silicate such as tetraethylorthosilicate is mixed and stirred. After the resulting solution is allowed to stand for 30 minutes, the supernatant containing silicon oxide particles that have not adhered to the phosphor surface is removed. Next, alcohol mixing, stirring, standing, and removal of the supernatant are repeated several times, and then a vacuum treatment is performed at 150 ° C. for 2 hours to obtain a surface-treated phosphor.
In addition to the surface treatment method of the phosphor, for example, a method of attaching spherical silicon oxide fine powder to the phosphor, a method of attaching a silicon compound film to the phosphor, and coating the surface of the phosphor fine particles with polymer fine particles Methods, a method of coating the phosphor with an organic material, an inorganic material, a glass material, etc., a method of coating the surface of the phosphor by a chemical vapor reaction method, a method of attaching metal compound particles, and the like can be used.

  Examples of the crystal structure of the phosphor include an orthosilicate crystal structure such as (Ba, Sr, Ca, Mg) 2SiO4: Eu, and a garnet crystal structure such as Ca3 (Sc, Mg, Na, Li) 2Si3O12: Ce. , (Sr, Ca, Ba, Mg) 10 (PO 4) 6 Cl 2: Eu and other apatite crystal structures, M 3 Si 6 O 12 N 2: Eu (where M represents an alkaline earth metal element), etc. Can be mentioned. Among these, an orthosilicate crystal structure or a garnet crystal structure is preferable.

(Green phosphor)
The emission peak wavelength of the green phosphor is usually 500 nm or more, preferably 510 nm or more, more preferably 515 nm or more, and usually 550 nm or less, especially 542 nm or less, and more preferably 535 nm or less. If this emission peak wavelength λp is too short, it tends to be bluish, while if it is too long, it tends to be yellowish, and there is a possibility that the characteristics as green light will deteriorate.
In addition, the half-value width of the emission peak of the green phosphor is usually 10 nm or more and usually 130 nm or less, and is preferably adjusted as appropriate according to the application. If the full width at half maximum FWHM is too narrow, the emission intensity may decrease, and if it is too wide, the color purity may decrease.
The green phosphor has an external quantum efficiency of usually 60% or more, preferably 70% or more, and a median diameter D50 is usually about 1 μm.
As a specific example of the green phosphor, a europium-activated alkaline earth silicon oxynite represented by (Mg, Ca, Sr, Ba) Si2O2N2: Eu which is composed of fractured particles having a fracture surface and emits light in the green region. Ride type phosphors and the like can be mentioned.

  Other green phosphors include Eu-activated aluminate phosphors such as Sr4Al14O25: Eu, (Ba, Sr, Ca) Al2O4: Eu, (Sr, Ba) Al2Si2O8: Eu, (Ba, Mg) 2SiO4 : Eu, (Ba, Sr, Ca, Mg) 2SiO4: Eu, (Ba, Sr, Ca) 2 (Mg, Zn) Si2O7: Eu, (Ba, Ca, Sr, Mg) 9 (Sc, Y, Lu, Gd) 2 (Si, Ge) 6O24: Eu activated silicate phosphor such as Eu, Y2SiO5: Ce, Tb activated silicate phosphor such as Ce, Tb, Eu activated phosphoric acid borate such as Sr2P2O7-Sr2B2O5: Eu Salt phosphors, Eu-activated halosilicate phosphors such as Sr2Si3O8-2SrCl2: Eu, Mn-activated silicate phosphors such as Zn2SiO4: Mn, Tb-activated aluminate fluorescence such as CeMgAl11O19: Tb, Y3Al5O12: Tb body Tb activated silicate phosphor such as Ca2Y8 (SiO4) 6O2: Tb, La3Ga5SiO14: Tb, (Sr, Ba, Ca) Ga2S4: Eu, Tb, Sm activated thiogallate phosphor such as Eu, Tb, Sm, Y3 ( Al, Ga) 5O12: Ce, (Y, Ga, Tb, La, Sm, Pr, Lu) 3 (Al, Ga) 5O12: Ce activated aluminate phosphors such as Ce, Ca3Sc2Si3O12: Ce, Ca3 (Sc , Mg, Na, Li) 2Si3O12: Ce activated silicate phosphor such as Ce, Ce activated oxide phosphor such as CaSc2O4: Ce, Eu activated oxynitride phosphor such as Eu activated β sialon, BaMgAl10O17 : Eu, Mn activated aluminate phosphors such as Eu and Mn, SrAl2O4: Eu activated aluminate phosphors such as Eu, and (La, Gd, Y) 2O2S: Tb activated oxysulfide fluorescence such as Tb Body, LaPO4: Ce, Tb-activated phosphate phosphors such as Ce and Tb, sulfide phosphors such as ZnS: Cu, Al, ZnS: Cu, Au, Al, (Y, Ga, Lu, Sc, La) BO3: Ce , Tb, Na 2 Gd 2 B 2 O 7: Ce, Tb, (Ba, Sr) 2 (Ca, Mg, Zn) B 2 O 6: Ce, Tb activated borate phosphors such as K, Ce, Tb, Ca 8 Mg (SiO 4) 4 Cl 2: Eu, Mn Eu, Mn activated halosilicate phosphors such as (Sr, Ca, Ba) (Al, Ga, In) 2S4: Eu activated thioaluminate phosphors and thiogallate phosphors such as Eu, (Ca, Sr) 8 (Mg, Zn) (SiO4) 4Cl2: Eu, Mn activated halosilicate phosphor such as Eu, Mn, M3Si6O9N4: Eu, M3Si6O12N2: Eu (where M represents an alkaline earth metal element). It is also possible to use Eu-activated oxynitride phosphors such as

In addition, as the green phosphor, it is also possible to use a pyridine-phthalimide condensed derivative, a benzoxazinone-based, a quinazolinone-based, a coumarin-based, a quinophthalone-based, a naltalimide-based fluorescent pigment, or an organic phosphor such as a terbium complex. is there.
Any one of the green phosphors exemplified above may be used, or two or more may be used in any combination and ratio.
(Orange to red phosphor)
The emission peak wavelength of the orange to red phosphor is usually in the wavelength range of 570 nm or more, preferably 580 nm or more, more preferably 585 nm or more, and usually 780 nm or less, preferably 700 nm or less, more preferably 680 nm or less. Is preferred.
Examples of such orange or red phosphors are europium activated alkaline earths composed of broken particles having a red fracture surface and represented by (Mg, Ca, Sr, Ba) 2Si5N8: Eu that emits light in the red region. Europium activated rare earth oxy represented by (Y, La, Gd, Lu) 2O2S: Eu, which is composed of silicon nitride phosphors and grown particles having a substantially spherical shape as a regular crystal growth shape, and emits light in the red region. Examples include chalcogenide phosphors.
In addition, the half-value width of the emission peak of the red phosphor is usually in the range of 1 nm to 50 nm.
The red phosphor has an external quantum efficiency of usually 60% or more, preferably 70% or more, and a median diameter D50 is usually about 1 μm.

And a phosphor containing oxynitride and / or oxysulfide containing at least one element selected from the group consisting of Ti, Zr, Hf, Nb, Ta, W and Mo, A phosphor containing an oxynitride having an alpha sialon structure in which some or all of the elements are substituted with Ga elements can also be used. These are phosphors containing oxynitride and / or oxysulfide.
Other red phosphors include Eu-activated oxysulfide phosphors such as (La, Y) 2O2S: Eu, Eu-activated oxide fluorescence such as Y (V, P) O4: Eu, Y2O3: Eu. (Ba, Mg) 2SiO4: Eu, Mn, (Ba, Sr, Ca, Mg) 2SiO4: Eu, Mn activated silicate phosphors such as Eu, Mn, LiW2O8: Eu, LiW2O8: Eu, Sm, Eu2W2O9 Eu activated tungsten phosphors such as (Ca, Sr) S: Eu, Eu activated aluminate phosphors such as YAlO3: Eu, Eu2W2O9: Nb, Eu2W2O9: Sm Eu-activated silicate phosphors such as, Ca2Y8 (SiO4) 6O2: Eu, LiY9 (SiO4) 6O2: Eu, (Sr, Ba, Ca) 3SiO5: Eu, Sr2BaSiO5: Eu, (Y, Gd) 3Al5O12: Ce, (Tb, Gd) 3Al5 12: Ce-activated aluminate phosphor such as Ce, (Mg, Ca, Sr, Ba) 2 Si 5 (N, O) 8: Eu, (Mg, Ca, Sr, Ba) Si (N, O) 2: Eu, (Mg, Ca, Sr, Ba) AlSi (N, O) 3: Eu-activated oxide such as Eu, nitride or oxynitride phosphor, (Sr, Ca, Ba, Mg) 10 (PO4) Eu, Mn activated halophosphate phosphor such as 6Cl2: Eu, Mn, Ba3MgSi2O8: Eu, Mn, (Ba, Sr, Ca, Mg) 3 (Zn, Mg) Si2O8: Eu, Mn attached Activated silicate phosphor, 3.5MgO · 0.5MgF 2 · GeO 2: Mn activated germanate phosphor such as Mn, Eu activated oxynitride phosphor such as Eu activated α sialon, (Gd, Y, Lu La) 2O3: Eu, Bi-activated oxide phosphors such as Eu and Bi, (Gd, Y, Lu, La) 2 2S: Eu, Bi-activated oxysulfide phosphor such as Eu, Bi, (Gd, Y, Lu, La) VO4: Eu, Bi-activated vanadate phosphor such as Eu, Bi, SrY2S4: Eu, Ce Eu, Ce activated sulfide phosphor such as CaLa2S4: Ce activated sulfide phosphor such as (Ba, Sr, Ca) MgP2O7: Eu, Mn, (Sr, Ca, Ba, Mg, Zn) 2P2O7 Eu, Mn activated phosphor phosphor such as Eu, Mn, (Y, Lu) 2 WO6: Eu, Mo activated tungstate phosphor such as Eu, Mo, (Ba, Sr, Ca) xSiyNz: Eu , Ce (where x, y, z represent an integer of 1 or more), etc., Eu, Ce-activated nitride phosphor, (Ca, Sr, Ba, Mg) 10 (PO4) 6 (F, Cl , Br, OH): Eu, Mn activated halophosphate phosphors such as Eu, Mn, ((Y, Lu, It is also possible to use Ce-activated silicate phosphors such as Gd, Tb) 1-x-yScxCey) 2 (Ca, Mg) 1-r (Mg, Zn) 2 + rSiz-qGeqO12 + δ.

Examples of red phosphors include β-diketonates, β-diketones, aromatic carboxylic acids, red organic phosphors composed of rare earth element ion complexes having an anion such as Bronsted acid as a ligand, and perylene pigments (for example, Dibenzo {[f, f ′]-4,4 ′, 7,7′-tetraphenyl} diindeno [1,2,3-cd: 1 ′, 2 ′, 3′-lm] perylene), anthraquinone pigment, Lake pigments, azo pigments, quinacridone pigments, anthracene pigments, isoindoline pigments, isoindolinone pigments, phthalocyanine pigments, triphenylmethane basic dyes, indanthrone pigments, indophenol pigments, It is also possible to use a cyanine pigment or a dioxazine pigment.
Among these, red phosphors include (Ca, Sr, Ba) 2 Si5 (N, O) 8: Eu, (Ca, Sr, Ba) Si (N, O) 2: Eu, (Ca, Sr, Ba). AlSi (N, O) 3: Eu, (Ca, Sr, Ba) AlSi (N, O) 3: Ce, (Sr, Ba) 3SiO5: Eu, (Ca, Sr) S: Eu, (La, Y) ) 2O2S: Eu or Eu complex, more preferably (Ca, Sr, Ba) 2Si5 (N, O) 8: Eu, (Ca, Sr, Ba) Si (N, O) 2: Eu, (Ca, Sr, Ba) AlSi (N, O) 3: Eu, (Ca, Sr, Ba) AlSi (N, O) 3: Ce, (Sr, Ba) 3SiO5: Eu, (Ca, Sr) S: Eu or (La, Y) 2 O2S: Eu or Eu (dibenzoylmethane) 3,1,10-phenanthroline complex Β-diketone Eu complex or carboxylic acid Eu complex of (Ca, Sr, Ba) 2 Si 5 (N, O) 8: Eu, (Sr, Ca) AlSi (N, O): Eu or (La, Y) 2O2S: Eu is particularly preferred.
Of the above examples, (Sr, Ba) 3SiO5: Eu is preferable as the orange phosphor.
In addition, orange or red fluorescent substance may use only 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

(Blue phosphor)
The emission peak wavelength of the blue phosphor is usually 420 nm or more, preferably 430 nm or more, more preferably 440 nm or more, and usually 490 nm or less, preferably 480 nm or less, more preferably 470 nm or less, more preferably 460 nm or less. Preferably it is.
In addition, the half-value width of the emission peak of the blue phosphor is usually in the range of 20 nm to 80 nm.
The blue phosphor has an external quantum efficiency of usually 60% or more, preferably 70% or more, and a median diameter D50 is usually about 1 μm.
As such a blue phosphor, europium-activated barium magnesium represented by (Ba, Sr, Ca) MgAl10O17: Eu, which is composed of growing particles having a substantially hexagonal shape as a regular crystal growth shape and emits light in a blue region. An aluminate phosphor, which is composed of growing particles having a substantially spherical shape as a regular crystal growth shape, emits light in a blue region (Mg, Ca, Sr, Ba) 5 (PO 4) 3 (Cl, F): Europium-activated calcium halophosphate phosphor represented by Eu, composed of growing particles having a substantially cubic shape as a regular crystal growth shape, and emitting light in the blue region (Ca, Sr, Ba) 2B5O9Cl: Europium represented by Eu Activated alkaline earth chloroborate phosphor, composed of fractured particles with fractured surface And (Sr, Ca, Ba) Al2O4: Eu or (Sr, Ca, Ba) 4Al14O25: Eu.

  In addition, as the blue phosphor, Sn-activated phosphate phosphors such as Sr2P2O7: Sn, (Sr, Ca, Ba) Al2O4: Eu or (Sr, Ca, Ba) 4Al14O25: Eu, BaMgAl10O17: Eu, (Ba, Sr, Ca) MgAl10O17: Eu, BaMgAl10O17: Eu, Tb, Sm, Eu activated aluminate phosphors such as BaAl8O13: Eu, Ce activated thiogallate phosphors such as SrGa2S4: Ce, CaGa2S4: Ce, Ba, Sr, Ca) MgAl10O17: Eu, Mn activated aluminate phosphor such as Eu, Mn, (Sr, Ca, Ba, Mg) 10 (PO4) 6Cl2: Eu, (Ba, Sr, Ca) 5 ( PO4) 3 (Cl, F, Br, OH): Eu-activated halophosphate phosphor such as Eu, Mn, Sb, BaAl2Si2O8: Eu, (Sr, Ba) 3MgSi2O8: E Eu-activated silicate phosphor such as Sr2P2O7: Eu, etc. Eu-activated phosphate phosphor, sulfide phosphor such as ZnS: Ag, ZnS: Ag, Al, and Ce-activated silicate such as Y2SiO5: Ce Phosphor, tungstate phosphor such as CaWO4, (Ba, Sr, Ca) BPO5: Eu, Mn, (Sr, Ca) 10 (PO4) 6, nB2 O3: Eu, 2SrO, 0.84 P2 O5, 0.16 B2 O3: Eu, Mn activated boric acid phosphor such as Eu, Sr2Si3O8 · 2SrCl2: Eu activated halosilicate phosphor such as Eu, SrSi9Al19ON31: Eu activated oxynitride phosphor such as Eu, EuSi9Al19ON31, La1-xCexAl (Si6-zAlz) (N10-zOz) (where x and y are numbers satisfying 0≤x≤1 and 0≤z≤6), La1-x-yCexCayAl (Si6-zAlz) (N10-zOz) Here, x, y, and z are numbers satisfying 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, and 0 ≦ z ≦ 6, respectively. It is also possible.

In addition, as the blue phosphor, for example, naphthalic acid imide-based, benzoxazole-based, styryl-based, coumarin-based, pyrarizone-based, triazole-based compound fluorescent dyes, organic phosphors such as thulium complexes, and the like can be used. .
Among the above examples, as the blue phosphor, (Ca, Sr, Ba) MgAl10O17: Eu, (Sr, Ca, Ba, Mg) 10 (PO4) 6 (Cl, F) 2: Eu or (Ba, Ca) , Mg, Sr) 2SiO \ f14: Eu, (Ca, Sr, Ba) MgAl10O17: Eu, (Sr, Ca, Ba, Mg) 10 (PO4) 6 (Cl, F) 2: Eu or More preferably, (Ba, Ca, Sr) 3MgSi2O8: Eu is included, and BaMgAl10O17: Eu, Sr10 (PO4) 6 (Cl, F) 2: Eu or Ba3MgSi2O8: Eu is more preferable. Of these, (Sr, Ca, Ba, Mg) 10 (PO4) 6Cl2: Eu or (Ca, Sr, Ba) MgAl10O17: Eu is particularly preferred for illumination and display applications.
In addition, only 1 type may be used for blue fluorescent substance and it may use 2 or more types together by arbitrary combinations and a ratio.

(Yellow phosphor)
The emission peak wavelength of the yellow phosphor is usually in the wavelength range of 530 nm or more, preferably 540 nm or more, more preferably 550 nm or more, and usually 620 nm or less, preferably 600 nm or less, more preferably 580 nm or less. .
Further, the half-value width of the emission peak of the yellow phosphor is usually in the range of 60 nm to 200 nm.
The yellow phosphor has an external quantum efficiency of usually 60% or more, preferably 70% or more, and a median diameter D50 is usually about 1 μm.
Examples of such yellow phosphors include various oxide-based, nitride-based, oxynitride-based, sulfide-based, and oxysulfide-based phosphors.
In particular, RE3M5O12: Ce (where RE represents at least one element selected from the group consisting of Y, Tb, Gd, Lu, and Sm, and M is selected from the group consisting of Al, Ga, and Sc) Or a garnet represented by Ma3Mb2Mc3O12: Ce (where Ma is a divalent metal element, Mb is a trivalent metal element, and Mc is a tetravalent metal element). Garnet-based phosphor having a structure, AE2MdO4: Eu (where AE represents at least one element selected from the group consisting of Ba, Sr, Ca, Mg, and Zn, and Md represents Si and / or Orthosilicate phosphors represented by Ge), etc., oxynitride phosphors obtained by substituting part of oxygen of the constituent elements of these phosphors with nitrogen, AEAlSi (N, O) 3: C (Here, AE represents at least one element selected from the group consisting of Ba, Sr, Ca, Mg and Zn.) Fluorescence activated with Ce such as a nitride-based phosphor having a CaAlSiN3 structure such as The body is mentioned.

Other yellow phosphors include sulfide phosphors such as CaGa2S4: Eu, (Ca, Sr) Ga2S4: Eu, (Ca, Sr) (Ga, Al) 2S4: Eu, and Cax (Si, Al). 12 (O, N) 16: a phosphor activated by Eu such as an oxynitride phosphor having a sialon structure such as Eu, (M1-a-bEuaMnb) 2 (BO3) 1-p (PO4) pX ( M represents one or more elements selected from the group consisting of Ca, Sr, and Ba, and X represents one or more elements selected from the group consisting of F, Cl, and Br. b and p represent numbers satisfying 0.001 ≦ a ≦ 0.3, 0 ≦ b ≦ 0.3, and 0 ≦ p ≦ 0.2, respectively). It is also possible to use an activated halogenated borate phosphor.
Examples of yellow phosphors include brilliant sulfoflavine FF (Color Index Number 56205), basic yellow HG (Color Index Number 46040), eosine (Color Index Number 45G80), 45G Etc. can also be used.

Furthermore, a bis (triazinylamino) stilbene disulfonic acid derivative, a bisstyryl biphenyl derivative (ultraviolet excitation 400 to 450 nm fluorescence), or the like can also be used.
In particular, nanophosphor: Si nanophosphor, ZnS nanophosphor, YAG: Ce nanophosphor, LaPO4: Ln nanophosphor, dye-doped silica nanophosphor, semiconductor nanoparticle, CdSe-ZnS quantum dot, etc. Since the diameter is much smaller than the relief period of the hologram relief, it can be formed uniformly on the relief surface, and the formation thickness is easy to control. When the semiconductor thin film is formed by ultra-fine processing, the semiconductor thin film can be formed with high precision and an ultra-thin film, and the coherence can be improved by controlling the waveform and intensity of the emitted light.
In the fluorescent semiconductor quantum dot, the central core (core) is made of, for example, cadmium selenide (CdSe), and the outer side thereof is covered with a zinc sulfide (ZnS) coating layer (shell). Yes. By changing the diameter of the metal compound, the emitted fluorescence wavelength changes. Since the biopolymer arranged around the quantum dot has a reactive group peculiar to the biopolymer, the phosphor can be specifically arranged using the reactive group.

As the ultraviolet light-emitting phosphor, the peak of the fluorescence spectrum that is emitted when excited by ultraviolet light and returns to a lower energy level is in a wavelength region such as blue, green, and red. Such ultraviolet light emitting phosphors include, for example, Ca2 B5 O9 Cl: Eu2 +, CaWO4, ZnO: Zn, Zn2 SiO4: Mn, Y2 O2 S: Eu, ZnS: Ag, YVO4: Eu, Y2 O3: Eu, There are Gd2 O2 S: Tb, La2 O2 S: Tb, Y3 Al5 O12: Ce, etc., and these are used as a single substance, or several of them are mixed and used in an appropriate ratio.
These have peaks in the fluorescence spectrum outside the blue, red, and green wavelength regions. Further, the weight ratio of the ultraviolet fluorescent substance in the ink is not limited as long as the fluorescence can be detected by the light receiving element of the reading head.
On the other hand, some infrared light emitting phosphors have the property of receiving visible light having a wavelength λ2 upon receiving excitation light having a wavelength λ1, and having the properties of λ1 = λ2 and λ1> λ2. Examples of such infrared light emitting phosphors include YF3: Yb, Er, ZnS: CuCO, and the like.

Specific examples include Lumogen FV Violet 570 (Naphthalimide: 374 nm → 413 nm), Lumogen F Yellow 083 (perylene: excitation wavelength 476 nm → emission wavelength 490 nm: the same applies hereinafter), Lumogen F orange (perylene: 525 nm → 539 nm). ), Lumogen F Red 305 (perylene: 578 nm → 613 nm), etc.
Fluorescent pigments manufactured by Deigro: Gropril T / GT series, ACT series, Z / ZQ series, GPL series, LHY series, Fluorescent dyes: DIVELIGHT D-818 Roanoke yellow, D-784 ALPARTA yellow, D-208 APACHI yellow D-288 Cherokee Red, D-688 Colorado Red, D-298 Columbia Blue, etc.
Fluorescent pigments manufactured by Sinloi: Sinroicolor FZ-2000 series (FZ-2001RED, etc.), FZ-2800 series (FZ-2808 Blue, etc.), SX-100 series (SX-104 Orange, etc.), SX-1000 series (SX-1004 Orange) SX-1005 Lemon Yellow, SX-1007 Pink, SX-1037 Magenta: average particle size 1.0 μm or less, SW-10 series (SW-11 Red Orange, SW-12NG Green, SW-13 Red Orange, SW-14 NO Orange, SW-15N Lemon Yellow , SW-16N Orange Yellow, SW-07Cerise, SW-17Pink, SW-27Rose, SW-37Rubine, SW-47Viole , SW-28Blue: average particle size 1.0 μm or less), SP series, SF-3000 series (ultrafine particle type), SF-5000 series (ultrafine particle type), SF-8000 series (ultrafine particle type), Lumilite Nano RY202 ( Particle size 30 nm, 365-370 nm → 619 nm), etc.

Manufactured by Moritechx Co., Ltd .: fluorescent particles (green: 468 nm → 508 nm) G25 (particle size 0.03 μm), G40 (particle size 0.04 μm), G50 (particle size 0.05 μm), G75 (particle size 0.07 μm), G85 (particle size 0.09 μm), G100 (particle size 0.10 μm), G140 (particle size 0.14 μm), G200 (particle size 0.20 μm), G250 (particle size 0.25 μm), G300 (particle size 0) .30 μm), G400 (particle size 0.40 μm), G450 (particle size 0.45 μm), G500 (particle size 0.50 μm),
Fluorescent particles (green: 360 nm → 530 nm) 34-1 (average particle size 3.0 μm),
Fluorescent particles (blue: 365 nm → 447 nm) B50 (particle size 0.05 μm), B100 (particle size 0.10 μm), B150 (particle size 0.14 μm), B200 (particle size 0.20 μm), B300 (particle size 0) .30 μm), B400 (particle size 0.40 μm), B500 (particle size 0.50 μm),
Fluorescent particles (red: 542 nm → 612 nm) B50 (particle size 0.05 μm), B60 (particle size 0.05 μm), B100 (particle size 0.10 μm), B160 (particle size 0.16 μm), B200 (particle size 0) .20 μm), B300 (particle size 0.30 μm), B400 (particle size 0.40 μm), B500 (particle size 0.50 μm), etc.

UV excitation fluorescent pigments UVP-1 (emission wavelength 421 nm), UVB-1 (emission wavelength 453 nm), UVG-2 (emission wavelength 517 nm), UVR-2 (emission wavelength 626 nm), visible light excitation fluorescent pigment LMS-570 (450-520 nm → 570 nm), LMS-560 (450-467 nm → 560 nm), LMS-550 (450-465 nm → 550 nm), LMS-540 (450-465 nm → 540 nm), etc.
Qdot525 nanocrystal (350-488 nm → 525 nm), Qdot565 nanocrystal (350-488 nm → 565 nm), Qdot585 nanocrystal (350-488 nm → 585 nm), Qdot605 nanocrystal (350-488 nm → 605 nm), Qdot625 nano Crystal (350-488 nm → 625 nm), Qdot655 nanocrystal (350-488 nm → 655 nm), Qdot705 nanocrystal (350-488 nm → 705 nm), Qdot800 nanocrystal (350-488 nm → 800 nm), etc.
Evidot manufactured by Evident Technologies, Inc .: CdSe / ZnS core shell Evidot (average particle size 7.2 to 9.6 nm, emission wavelength 490 nm to 620 nm), etc.
Quantum dots manufactured by Nippon Quantum Design Co., Ltd .: carboxyl group type, amino group type: diameters of 3.0 nm to 8.3 nm and emission wavelengths of 530 nm to 620 nm can be suitably used.

Next, the principle of holography will be described.
If an object is illuminated with coherent light and light diffracted from the object illuminates a recording medium (photoresist, etc.), the object wave is diffracted from the object and reaches the recording surface.
F (x, y) = A (x, y) EXP [φ (x, y)]
It is expressed. here,
A (x, y) is the amplitude distribution of the object wave,
φ (x, y) is a phase distribution.
At this time, the intensity distribution of the light wave reaching the recording medium is recorded on the recording medium. Its intensity distribution is
I (x, y) = | F (x, y) | ² = A ² (x, y) (1)
Thus, the phase distribution is not recorded.
Here, when an object wave and a coherent light wave (referred to as a reference wave) are superimposed, the intensity distribution of the recorded light wave is
I (x, y) = | F (x, y) + R (x, y) | ²
= | F (x, y) | ² + | R (x, y) | ²
+ F (x, y) R ^* (x, y) + F ^* (x, y) R (x, y) (2)
It becomes. (* Represents a complex conjugate term.)

However, if the reference light is a plane wave incident on the recording surface at an angle θ,
R (x, y) = r (x, y) EXP (2πiαx) (3)
Write,
α = SIN (θ) / λ (4)
It is. In the first and second terms of (2), the phase information is missing for both the intensity of the object wave and the intensity of the reference wave. The third term and the fourth term are interference terms. F (x, y) R * (x, y) =
A (x, y) r (x, y) EXP [i [φ (x, y) -2παx]] (5)
F * (x, y) R (x, y) =
A (x, y) r (x, y) EXP [-i [[phi] (x, y) -2 [pi] [alpha] x]] (6)
The phase term φ (x, y) of the object remains. (5) and (6) are complex conjugates of each other, and the third term in (4.2) includes the complex amplitude distribution of the object. Substituting (5) and (6) into (2),
I (x, y) = | F (x, y) | ² + | R (x, y) | ²
+ 2A (x, y) r (x, y) COS [2παx−φ (x, y)] (7)
It becomes. It can be seen that the object wave and the reference wave interfere to form an interference fringe.

In this way, holography is a method in which a reference wave is superimposed on an object wave and interference recording is performed, and the phase information of the object is recorded without being lost. A recording of (7) is called a “hologram”. The intensity transmission or amplitude reflectance of the hologram is the recorded intensity distribution I (x, y)
Proportional,
T (x, y) = τI (x, y) (8)
Let's call it. When the reference wave used when recording on this hologram is at a predetermined angle, the wavefront transmitted or reflected by the hologram is
T (x, y) R (x, y) = τ (| F (x, y) | ² + | R (x, y) | ² )
+ ΤF (x, y) | R (x, y) | ²
+ ΤF ^* (x, y) R ² (x, y) (9)
Can be expressed. This second term is τF (x, y) | R (x, y) | ² =
τA (x, y) r ² (x, y) EXP [iφ (x, y)]] (10)
The third term is
τF * (x, y) R ² (x, y) =
τA (x, y) r ² (x, y) EXP [−iφ (x, y) + 2πiα] (11)
Call it.

Therefore, the first term of (9) is a light beam penetrating the hologram in the same direction as the illumination light or a specularly reflected light beam, and the second term is a light wave having an amplitude proportional to the object light from (10). From (11), it can be seen that the third term is a light wave having a phase distribution conjugate with the object wave and propagating in the direction of 2θ.
In this way, the complex amplitude distribution can be recorded and reproduced using the holographic technique.
In the case of the present invention, the amplitude transmittance or reflectance of the hologram is proportional to the recorded intensity distribution and is expressed by the equation (8), but the reference wave used when recording on this hologram. Is not a predetermined angle, but a light-emitting wave having a spatial distribution similar to the amplitude transmittance or amplitude reflectance of (8) is emitted from this hologram.
Therefore, the emission wave is emitted while maintaining the phase term already recorded in the hologram, regardless of the conventional principle of hologram reproduction in which the phase term recorded in the hologram is given to the reference light. Therefore, theoretically, it has a three-dimensional continuous curved light emitting surface having a spatial function including the phase difference of an object, and light is emitted from the one curved surface.

To simplify the conventional hologram reproduction principle for the transmission type, when parallel light as reference light is applied to the hologram, the parallel light is shielded in the shielding part, and the parallel light is transmitted only from the transmission part. Diffraction occurs at the boundary between the transmission part and the shielding part, receives the phase term of the object, and the entire component transmitted through the hologram is superimposed, which becomes the hologram reproduction light and reaches the observer's eyes.
In the case of the present invention, there is no parallel light as the reference light described above, and the emitted light retains the phase term of the object when emitting light on the light emitting surface provided in contact with the hologram relief. Hologram reproduction is performed by an interference phenomenon between radiated lights.
The interference effect between synchrotron radiation that does not have temporal and spatial coherence does not cause sufficient interference like laser light, but hologram reproduction is performed at the same level as when a hologram is illuminated with low coherent light. . Since the reproduction is based on the principle as described above, the reference light at the time of hologram photographing is preferably parallel light (because complicated reference light cannot be reproduced), or “hologram represented by a diffraction grating” (diffraction The grating is preferably both object light and reference light.) The diffraction grating formed by electron beam drawing, such as a computer generated hologram, is precise and suitable.

Further, for the above reason, in order to make the hologram reproduction image clearer, it is necessary to give the radiation light a characteristic similar to temporal or spatial coherence, for example, the light emitting surface of the light emitter. It is desirable to reduce the thickness of the light emission and to narrow the emission wavelength width. Further, the excitation light source is also preferably a small shape, and a spot shape or the like is particularly suitable.
In addition, it is desirable that the wavelength difference between the excitation light for exciting the illuminant and the emission wavelength is large, and it is also effective to amplify only the emission light by filtering the excitation light during observation.
As an excitation light source, energy such as ultraviolet rays, visible rays, electron beams, X-rays and the like, and depending on the case, a light source capable of emitting infrared energy can be used to emit fluorescence, etc. In order to use it for hologram authentication, it is necessary to use a light source corresponding to the phosphor, and an ultraviolet light source, a visible light source having a predetermined intensity, wavelength, and size of an illumination spot, an infrared light source is used in some cases. .
From the fluorescent layer provided so as to be in contact with the hologram relief surface by illumination by these light sources, and more specifically, from the phosphor contained in the fluorescent layer, fluorescence of a wavelength different from the wavelength of the illumination light source, etc. To express. Since the fluorescence emission and the like have the same spatial phase as the hologram relief and have a wavelength (fluorescence wavelength) different from that of the illumination light source, the direction of specularly reflected light (0th order diffracted light) by the hologram relief, illumination The hologram image is reproduced in a direction different from the diffraction direction by the light wavelength (excitation light wavelength), that is, in the diffraction direction by the fluorescence wavelength.

However, when the thickness of the fluorescent layer is distributed on the hologram surface irrespective of the hologram relief, the fluorescence emission intensity distribution resulting from the thickness distribution may be reproduced in some cases. Unnecessary interference with light can occur, which can be a cause of blurring of the hologram reproduction image.
In order to eliminate this factor, the fluorescent layer is formed with a uniform thickness following the irregularities forming the hologram relief so that light emission of the same intensity can be generated from any position on the hologram relief surface. The reproduced image can be sharpened.
When ultraviolet light or infrared light other than visible light is used as the illumination light (excitation light) of the hologram sheet of the present invention, the light is not visible to the observer, and the hologram reproduction image is seen from the place where there is no illumination light. However, even if the illumination light is temporally and spatially coherent, as a result, this hologram reconstructed image emits light through a process of excitation and fluorescence. Therefore, the temporal and spatial coherence between the emitted lights is small, although the phase of the spatial hologram at the time of emission is included, the hologram reproduction image is a normal laser reproduction relief hologram. It is weaker than the reproduced image and is unclear.
Of course, if only observing the beam-shaped diffracted light, it is easy to check its color tone and diffraction direction, and it can be used as it is to judge the authenticity. In order to allow the observer to recognize the image and accurately determine its presence, the luminous performance of the phosphor is improved, and the diffraction angle is increased to increase the wavelength-diffraction angle dependency. It is necessary to increase the difference in the fluorescent light diffraction angle and further reduce the thickness of the fluorescent layer to suppress variation in the thickness direction of the fluorescent layer and make it uniform. (Since the light emitting surface contains phase information, its spatial shape is accurately reproduced.)

Furthermore, in order to express temporal coherence, excitation is performed with a pulse laser of 10 ⁻¹⁵ sec or less as a light source, and illumination is performed with a time interval between pulses of 10 ⁻⁷ sec or more that is a fluorescence emission time. It is also suitable. Thus, one fluorescent light emitting surface generated by one excitation pulse does not cause a disturbance phenomenon with the fluorescent light emitting surface generated by the next excitation pulse, and one fluorescent light emitting surface expressed by one pulse. Due to the holographic interference phenomenon caused by the above, a clear hologram reproduction image can be observed. Of course, even if a strobe light source that is simply turned on and off in seconds is used, the viewer seems to emit light continuously. When confirming with the above, the above-described effects can be sufficiently obtained.
The phosphor layer is made of phosphor ink mixed with resin or dispersed in a solvent (or water) on the hologram relief by gravure method, offset method, silk screen method, nozzle coating method or ink jet method. Can be formed.
At this time, by adjusting the content ratio of the phosphor in the fluorescent ink, the formed fluorescent layer can be formed with a uniform thickness following the unevenness forming the hologram relief.
The unevenness of the hologram relief is, for example, a gentle curve having an unevenness of a depth of 0.01 μm with a period of 1 μm level and can be regarded as a substantially flat surface. 1 to 10 pascals / second), exhibiting the leveling effect due to the weight of the ink itself, and by setting the solid content in the ink to 20% or less, further 10% or less, for example, for a thickness of 1 μm The variation can be suppressed to 1/10 or less, and further to 1/20 or less.
Here, although the fluorescent layer is on the order of 1 μm, in order to improve the clarity of the hologram reproduction image, it is preferable to make the fluorescent layer thin. For this purpose, the size of the phosphor is about 1.0 μm or less. Hereinafter, for example, 0.1 μm to 0.5 μm, more preferably 0.5 μm to 0.1 μm, more preferably 3 to 10 nm, and the dots are uniformly scattered in the hologram relief surface, and the thickness direction of the fluorescent layer In this case, it is preferable that the phosphor is arranged in the order of 1 to 10 particles or 1 to 3 particles as a unit.
In particular, the nozzle coating method and the ink jet method can be formed only with a solvent and a phosphor without using a resin, and can be formed very thin as a phosphor layer (for one to three phosphors, etc.). Therefore, it is preferable. A resin may be formed thereon to fix the phosphors.
As described above, when the phosphor particles are directly formed on the first transparent resin layer, when the second transparent resin layer is formed thereon, the first transparent resin layer and the second transparent resin layer are in direct contact with each other, and Since the interface becomes the hologram relief surface, the reflected light at this interface reproduces the hologram image and overlaps with the hologram reproduction image that should be reproduced originally (the reproduction is performed with the illumination light source wavelength, and the diffraction angle is slightly shifted and reproduced). ), Deteriorating its clarity. Of course, when there is no 2nd transparent resin layer, it becomes an interface with air and a deterioration degree becomes strong.
For this reason, the difference in refractive index is preferably within 0.3, more preferably within 0.05. If possible, the same resin as the first transparent resin (refractive index difference “0”) is used to make the second difference. By forming the transparent resin layer, the hologram reproduction image of the present invention can be made clear.
Furthermore, for example, when a hologram sheet in which the first transparent resin layer and the second transparent resin layer are formed of the same resin is observed under normal illumination, a very thin film-like surface of the phosphor is present in one sheet. It looks like it is floating, and when a predetermined illumination light is applied to this sheet, it brings about the unexpectedness that a three-dimensional hologram appears.
This effect is that when the phosphor is an ultrafine particle, that is, when the particle diameter is 0.1 μm or less, and further 0.01 μm or less, the fluorescent layer becomes transparent, and the above-described very thin film-like surface is eliminated and completely transparent. A hologram sheet excellent in design and authenticity, in which a hologram suddenly appears from a simple sheet, can be provided.

The third aspect of the hologram sheet of the present invention is:
The fluorescent layer is formed only in the concave and convex recesses forming the hologram relief, and further, a transparent resin layer having a refractive index difference with the transparent resin layer within 0.3 is provided thereon. It is a feature.
According to the hologram sheet of the third aspect,
The said fluorescent layer is formed only in the uneven | corrugated recessed part which forms the said hologram relief, Furthermore, the transparent resin layer whose refractive index difference with the said transparent resin layer is less than 0.3 is provided on it. 1 is provided.
The hologram relief has an irregular shape with a period of about 1 μm, a depth of 0.01 μm, and a maximum of 0.5 μm. By providing a fluorescent layer only in this recess, the hologram relief is synchronized with the period of the hologram relief. The presence or absence of a fluorescent layer, that is, the presence or absence of fluorescent emission can be provided.
The concave portion of the hologram relief is a concave portion when the fluorescent layer is formed on the hologram relief, and becomes the convex portion side when observed from the normal observation method, that is, from the hologram forming layer side. In order to form the light emission intensity distribution using the presence or absence of the fluorescent layer, it may be formed partially on either the concave or convex portion, and the entire concave portion may be filled with the fluorescent layer or the lowest portion of the concave portion. You may form in only a part of. However, since it is necessary to synchronize the phase distribution and the distribution to be formed, when forming a part thereof, it is necessary to always form the same phosphor at the same position.
As a method for selectively forming the fluorescent layer in the concave portion, a phosphor having a very small particle size (particle size is 10 nm, etc., not including a resin) dispersed in a solvent or the like is used. Alternatively, the fluorescent ink layer may be formed and the phosphor particles may move from the convex portion to the concave portion under its own weight while the solvent is volatilized.

Also, a regular diffraction grating is provided, and the phosphor layer uniformly provided thereon is tuned to the regular diffraction grating using photolithography, and is exposed, developed, and etched, so that the unevenness and the phosphor layer are synchronized. It can also be provided. According to this method, it is possible to control the thickness and size of the fluorescent layers scattered in the respective recesses, so that it can be formed “uniformly” on the entire relief surface.
What is formed by the above method includes the phase information of the hologram relief described in the hologram principle described above, and further includes amplitude information synchronized with the phase information. Is.
Therefore, the hologram light information of both the phase hologram and the amplitude hologram can be included in the emitted light, and a clearer hologram can be obtained.
Thereby, the designability and authenticity determination property can be improved.
Also in the case of this embodiment, as described in the first and second embodiments, the first transparent resin layer and the second transparent resin layer are in direct contact with each other at the interface where the fluorescent layer is not formed, and the interface between them. Since this becomes a hologram relief surface, the same effects as those of the first and second embodiments can be obtained by providing the second transparent resin layer of the present invention.
The fourth aspect of the hologram sheet of the present invention is
The fluorescent layer has a thickness of 0.01 μm or more and 0.5 μm or less.
According to the hologram sheet of the fourth aspect,
The hologram sheet according to claim 2 or 3, wherein the fluorescent layer has a thickness of 0.01 µm to 0.5 µm.
From the above-mentioned principle of hologram, in order to increase the linear brightness of the hologram reproduction image, it is desirable that the fluorescent layer is thin. However, the thinner the thickness, the weaker the fluorescence emission intensity during hologram reproduction. The layer thickness must be 0.003 μm or more and 1.0 μm or less, and more preferably 0.01 μm or more and 0.5 μm or less.
If it is less than 0.003 μm (one phosphor of the smallest particle size), the fluorescence emission intensity is too weak, and even if amplified using a photomultiplier tube, it is difficult to distinguish it from noise such as stray light. The emission intensity is sufficient for the purpose of the present invention, but the position of the curved surface carrying the phase information of the hologram relief is caused by the emission of a plurality of phosphors in the thickness direction. A plurality of holograms are present in the thickness direction, and as a result, the hologram reproduction image becomes unclear.
On the other hand, the fluorescence emission intensity is ensured as 0.01 μm or more (for three phosphors having the smallest particle diameter), and the position of the curved surface carrying the phase information is clarified as 0.5 μm or less, so that a hologram reproduction image can be obtained. It shall be clear.
In the case of this aspect, as described in the first and second aspects, the first transparent resin layer and the second transparent resin layer are in direct contact with each other, and the interface is a hologram relief surface. By providing the second transparent resin layer, an effect larger than that of the first and second embodiments can be obtained.

According to the hologram sheet of the present invention,
A hologram sheet, wherein a transparent resin layer having a hologram relief including a diffraction grating group corresponding to a hologram image is provided on one surface of a transparent substrate, and a fluorescent layer is provided so as to be in contact with the hologram relief Design and authenticity that has a hologram reconstructed image with a wavelength different from the wavelength of illumination light, suppresses unnecessary reflected light, etc., and also brings about the unexpectedness that a hologram appears from a transparent sheet A hologram sheet excellent in determinability is provided.

Is a Jablonsky diagram. These are sectional drawings of hologram sheet A showing one example of the present invention. (This is an example in which the fluorescent layer is “formed with a uniform thickness following the concavities and convexities forming the hologram relief”, and the illustration in the case where the fluorescent layer is provided so as to be in contact with the fluorescent layer is omitted.) These are sectional drawings of hologram sheet A 'showing other 1 examples of the present invention. (Example in which the fluorescent layer is “formed only on the concave and convex portions forming the hologram relief”) Is the process of determining one embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Transparent substrate) The transparent substrate 1 used in the present invention can be reduced in thickness, and can withstand mechanical strength and solvent resistance and heat resistance that can withstand processing when manufacturing the hologram sheet A. Those having the following are preferred. Since it depends on the purpose of use, it is not limited, but a film-like or sheet-like plastic is preferable.
For example, various plastic films such as polyethylene terephthalate (PET), polycarbonate, polyvinyl alcohol, polysulfone, polyethylene, polypropylene, polystyrene, polyarylate, triacetyl cellulose (TAC), diacetyl cellulose, and polyethylene / vinyl alcohol can be exemplified. .
Among them, those having resistance to excitation light such as ultraviolet rays, for example, those containing ultraviolet absorbers may be used. Those containing an ultraviolet absorber also have the effect of preventing unscheduled hologram reproduction, although faint due to ultraviolet rays contained in natural light or the like.
The thickness of the transparent substrate 1 is usually 5 to 100 μm, but in view of the visibility of the hologram reproduction image, it is preferably 5 to 50 μm, particularly 5 to 25 μm.

(Transparent resin layer having hologram relief: also referred to as first transparent resin layer: hologram forming layer)
As the transparent resin material for constituting the hologram forming layer 2 of the present invention, various thermoplastic resins, thermosetting resins, or ionizing radiation curable resins can be used. Thermoplastic resins include acrylic ester resins, acrylamide resins, nitrocellulose resins, or polystyrene resins. Thermosetting resins include unsaturated polyester resins, acrylic urethane resins, epoxy-modified acrylic resins, and epoxy-modified unsaturated resins. A polyester resin, an alkyd resin, a phenol resin, etc. are mentioned.
These thermoplastic resins and thermosetting resins can be used alone or in combination of two or more. One or more of these resins may be cross-linked using various isocyanate resins, or various curing catalysts, for example, metal soap such as cobalt naphthenate or zinc naphthenate may be blended. Or peroxide such as benzoyl peroxide and methyl ethyl ketone peroxide for initiating polymerization with heat or ultraviolet light, benzophenone, acetophenone, anthraquinone, naphthoquinone, azobisisobutyronitrile, or diphenyl sulfide good.

Examples of the ionizing radiation curable resin include epoxy acrylate, urethane acrylate, acrylic-modified polyester, etc., for the purpose of introducing a crosslinked structure into such an ionizing radiation curable resin or adjusting the viscosity, A monofunctional monomer, a polyfunctional monomer, or an oligomer may be blended and used.
In order to form the hologram forming layer 2 using the above resin material, it can be directly formed by developing the photosensitive resin material by performing interference exposure of the hologram. It is preferable to perform molding by using a replica or a plating mold thereof as a replica mold and pressing the mold surface against the layer of the resin material.

When thermosetting resin or ionizing radiation curable resin is used, curing is performed by heating or ionizing radiation irradiation while keeping the uncured resin in close contact with the mold surface, and then cured by peeling after curing. The fine irregularities of the relief hologram can be formed on one side of the layer made of a transparent resin material. A diffraction grating forming layer having a diffraction grating formed in a pattern by a similar method can also be used as the optical diffraction structure.
A hologram is a recording of interference fringes due to interference of light between object light and reference light in an uneven relief shape. For example, a laser reproduction hologram such as a Fresnel hologram, a white light reproduction hologram such as a rainbow hologram, There are color holograms utilizing the above principle, computer generated holograms (CGH), holographic diffraction gratings and the like. Further, like a machine readable hologram, the reproduction light may be converted into data by a light receiving unit and transmitted as predetermined information, or authenticity determination may be performed.

In order to precisely create fine irregularities, not only optical methods, but also electron beam lithography equipment can be used to create precisely designed relief structures that produce more precise and complex reproduction light. Good. The relief shape is designed to have a pitch, depth, or specific periodic shape of the unevenness according to the wavelength (range) of the light or light source for reproducing or reproducing the hologram, the direction and the intensity of reproduction or reproduction.
In addition, a color hologram image is formed by a diffraction grating pixel consisting of diffraction grating lines (a minimum unit of a single diffraction grating area consisting of the same diffraction grating line. A set of light emitted from these pixels as diffracted light is one color hologram image. It is also possible to form the image by using an image processing method in which element decomposition is performed and a predetermined pixel size, grid line pitch, and grid line angle are assigned to each element and reproduced.
The pitch (period) of the unevenness depends on the reproduction or reproduction angle, but is usually 0.1 μm to several μm, and the depth of the unevenness is a factor that greatly affects the reproduction or reproduction intensity, but is usually 0.01 μm. ˜0.5 μm.
As in the case of a single diffraction grating, when the unevenness of exactly the same shape is repeated, as the adjacent unevenness is the same shape, the degree of interference of reflected light increases and the intensity increases, and the maximum value is reached. Converge. Diffraction in the diffraction direction is also minimized. When a single point of an image converges to a focal point, such as a stereoscopic image, the convergence accuracy to the focal point is improved, and a reproduced or reproduced image becomes clear.

The method of shaping (also called duplicating) the hologram relief shape is as follows. A master plate on which diffraction gratings and interference fringes are recorded in a concavo-convex shape is used as a press die (referred to as a stamper), and the master plate is placed on the transparent substrate 1. The concavo-convex pattern of the original plate can be duplicated by stacking and pressing them together by an appropriate means such as a heating roll. The hologram pattern to be formed may be single or plural.
In order to accurately reproduce the above-mentioned extremely fine shape and to minimize distortion and deformation such as heat shrinkage after replication, the original plate is made of metal and replicated at low temperature and high pressure.
For the original plate, a metal having high hardness such as Ni is used. After a Cr or Ni thin film layer is formed on the surface of a glass master or the like formed by optical imaging or electron beam drawing or the like by vacuum deposition or sputtering, Ni or the like is electrodeposited (electroplating, electroless plating) Further, it can be made by peeling the metal after forming 50 to 1000 μm by composite plating or the like.
The duplication method uses a flat plate type or a rotary type, the linear pressure is 0.1 ton / m to 10 ton / m, and the duplication temperature is usually 60 ° C. to 200 ° C.

(Fluorescent layer)
In the present invention, the fluorescent layer 3 is formed on the hologram relief surface of the hologram forming layer 2.
This fluorescent layer is produced by using a resin dispersion type fluorescent ink in which the phosphor is uniformly dispersed in a transparent resin or a solvent dispersion type fluorescent ink in which the phosphor is dispersed in water or a solvent, and using them, a printing method Further, by using various forming methods such as a coating method and an ink jet method, the hologram forming layer 2 is formed so as to be in contact with the hologram relief and to follow the hologram relief or partially in the recess. Can do.
In addition, after forming a fluorescent layer on the hologram forming layer 2, the photoresist pattern is recessed by exposing, developing, and removing unnecessary portions by aligning with the diffraction grating pattern by photolithography using a photoresist. The fluorescent layer can be removed by etching, leaving the fluorescent layer only in the recess.
On the contrary, a photoresist layer is formed on the hologram forming layer 2, aligned with the diffraction grating pattern, exposed to light, developed, and removed unnecessary portions to leave the photoresist on the convex portions and expose the concave portions. After forming the fluorescent layer, the photoresist on the convex portion is removed, and at the same time, the fluorescent layer directly above it is partially removed, so that the fluorescent layer can be left only in the concave portion.

The resin-dispersed fluorescent ink includes the above-described phosphor, a transparent resin, for example, an acrylic ester resin, an acrylamide resin, a nitrocellulose resin, or a polystyrene resin as a thermoplastic resin, and a thermosetting resin. Ball mills and kneaders using glass beads or steel beads to reduce secondary aggregation in unsaturated polyester resins, acrylic urethane resins, epoxy-modified acrylic resins, epoxy-modified unsaturated polyester resins, alkyd resins, or phenol resins Thoroughly kneading with a roll mill, etc., adjusting the viscosity with a solvent, etc., and using a gravure method, offset method, silk screen method, curtain coating method, nozzle coating method, and even an ink jet method as appropriate, a uniform thickness Can be formed.
In order to make the thickness of the fluorescent layer 0.003 μm or more and 1.0 μm or less, and further 0.01 μm or more and 0.5 μm or less, the solid content of the resin-dispersed ink is set to 1 to 10%, solvent or water For example, when the coating film in which the solvent is used is 10 μm, the thickness after evaporation of the solvent (the thickness of the fluorescent layer) is set to 1/10 to 1/100, and 1 μm to 0.1 μm.

Since the solvent-dispersed fluorescent ink does not include a resin component and includes only a phosphor and a solvent, the thickness of the fluorescent layer can be made thinner than that of the resin-dispersed type.
As a solvent, water, an alcohol solvent, a cellsolve solvent, or a paraffin solvent is used to disperse and hold a small particle phosphor and provided on the hologram forming layer 2 by curtain coating, nozzle coating or the like while stirring. be able to.
In this case, by adjusting the evaporation rate of the solvent, the phosphor can be moved to the recess by its own weight while the solvent is volatilized.
Furthermore, several μm of a slow volatile solvent having solubility is applied to the resin forming the hologram relief surface (a ketone solvent such as cyclohexanone for acrylic, vinyl chloride, vinyl acetate resin, polyester resin, etc.). It is also possible to dilute this solvent with a non-soluble solvent and use it to make the remaining components 0.1 μm or less.) Dissolve only the outermost surface of the hologram relief surface, Also suitable is a method of forming a fluorescent layer that imparts tackiness to the surface and sprays the phosphor as it is on the surface so that only phosphor particles in contact with the sticky surface remain on the hologram relief surface. is there.
According to this method, the fluorescent layer becomes almost one particle film, is formed uniformly on the hologram relief surface, and the fluorescence emission surface when the excitation light is applied from the hologram forming layer side is the same as the hologram relief surface.
In any case, the unevenness of the hologram relief is very small, so that the phosphor layer has a uniform thickness and the phosphor within it has a uniform density, or even on the hologram relief surface (partial formation) In this case, in order to form a uniform portion), it is preferable that the phosphor has a smaller particle size, and a nanophosphor is particularly suitable.

(Second transparent resin layer)
As a transparent resin material for constituting the second transparent resin layer 4 of the present invention, various thermoplastic resins, thermosetting resins, or ionizing radiation curable resins can be used. Thermoplastic resins include acrylic ester resins, acrylamide resins, nitrocellulose resins, or polystyrene resins. Thermosetting resins include unsaturated polyester resins, acrylic urethane resins, epoxy-modified acrylic resins, and epoxy-modified unsaturated resins. A polyester resin, an alkyd resin, a phenol resin, etc. are mentioned.
These thermoplastic resins and thermosetting resins can be used alone or in combination of two or more. One or more of these resins may be cross-linked using various isocyanate resins, or various curing catalysts, for example, metal soap such as cobalt naphthenate or zinc naphthenate may be blended. Or peroxide such as benzoyl peroxide and methyl ethyl ketone peroxide for initiating polymerization with heat or ultraviolet light, benzophenone, acetophenone, anthraquinone, naphthoquinone, azobisisobutyronitrile, or diphenyl sulfide good.
Examples of the ionizing radiation curable resin include epoxy acrylate, urethane acrylate, acrylic-modified polyester, etc., for the purpose of introducing a crosslinked structure into such an ionizing radiation curable resin or adjusting the viscosity, A monofunctional monomer, a polyfunctional monomer, or an oligomer may be blended and used.
However, in order not to generate interface reflection with the hologram forming layer 2, the same resin is used for the resin layer constituting the hologram forming layer 2, or even the same resin or other resin is refracted. Use those with the same rate or a difference within 0.3. Of course, the difference is more preferably within 0.05.
That is, polymethyl methacrylate (refractive index n = 1.49), polymethyl acrylate (n = 1.47), polybenzyl methacrylate (n = 1.57), polybutyl acrylate (n = 1.44), polyisobutyl Acrylate (n = 1.48), cellulose nitrate (n = 1.54), methylcellulose (n = 1.50), cellulose acetate propionate (n = 1.47), polystyrene (n = 1.60) , Polyethylene terephthalate (n = 1.64), polyvinyl acetate (n = 1.47), polyvinyl chloride / vinyl acetate (n = 1.54), melamine resin (n = 1.56), epoxy resin (n = 1.61), phenol resin (n = 1.60), etc., or a mixture thereof can be used as appropriate.
Although the formation method of a 1st transparent resin layer can be employ | adopted for the formation method of a 2nd transparent resin layer, In this case, it is necessary to use resin and a formation method which do not damage a fluorescent layer.
For example, use of a resin or solvent that is insoluble in the fluorescent layer or the phosphor, and in addition, unnecessary pressure in the horizontal direction may prevent the fluorescent particles fixed on the first transparent resin layer from causing unnecessary movement. It is preferable to use a formation method that does not apply (silk screen method, resin transfer method, etc., because only vertical pressure is applied).
Of course, it is most desirable to eliminate the interface itself between the two layers by forming the transparent resin used for forming the first transparent resin layer, and further forming the second transparent resin layer by the same ink and the same forming method.

Example 1
As the transparent substrate 1, a melamine resin composition (refractive index 1.56: first transparent resin layer) is applied to the surface of a 12 μm PET film, and a relief hologram (“fluorescence”) with a hologram image position detection pattern is applied. A relief hologram was formed by heat-curing the mold surface of the replication mold of the character image (see FIG. 4) while in contact with it to obtain a hologram forming layer 2 having a thickness of 3 μm.
On this hologram forming layer 2, a resin dispersed fluorescent ink having the following composition was coated by a gravure coating method and dried to form a fluorescent layer 3 having a thickness of 5 μm so as to be in contact with the hologram relief.
・ <Fluorescent ink composition>
UV excitation fluorescent pigment UVR-2 manufactured by Tale Navi Co., Ltd. 5 parts by weight Acrylic resin 10 parts by weight Methyl ethyl ketone 40 parts by weight Ethyl acetate 45 parts by weight Furthermore, as a second transparent resin layer, a polyvinyl chloride / vinyl acetate resin composition (n = 1.54.) Was applied to produce a hologram sheet (not shown) of the present invention.
When this hologram sheet was illuminated with a 365 nm wavelength light source (UV-LED module LC-L2 manufactured by Hamamatsu Photonics), as shown in FIG. It was confirmed that only the red reproduced image appeared to float in the space, and the design was excellent. At this time, unnecessary ultraviolet reflection could be suppressed.
When this hologram sheet is cut into a 3 cm square and pasted on a passport and illuminated with a black light fluorescent tube 40W (a cover with a 3 mmφ hole is used to reduce the illumination shape), a red hologram reproduction image can be recognized. did it.

(Example 2)
On the hologram forming layer 2 formed in the same manner as in Example 1, resin-dispersed fluorescent ink having the following composition was coated by a gravure coating method and dried to form a fluorescent layer 3 having a thickness of 0.1 μm.
・ <Fluorescent ink composition>
Lumilite nano RY202 (particle size 30 nm) 5 parts by weight Polyvinyl alcohol resin 10 parts by weight Isopropyl alcohol 40 parts by weight Water 45 parts by weight Furthermore, as a second transparent resin layer, a polyvinyl chloride / vinyl acetate resin composition (n = 1) .54.) Was applied to produce hologram sheet A of the present invention.
When this hologram sheet A was observed in the same manner as in Example 1, it was possible to more clearly confirm the red hologram reproduction image “fluorescence”, and only the red reproduction image appeared to float in the space. It was excellent. At this time, unnecessary ultraviolet reflection could be suppressed.
When this hologram sheet is cut into a 3 cm square and pasted on a passport and illuminated with a black light fluorescent tube 40W (a cover with a 3 mmφ hole is used to reduce the illumination shape), a red hologram reproduction image can be recognized. did it.

(Example 3)
The fluorescent ink is a solvent dispersion type having the following composition, the curtain coating method is used, the drying speed is slowed (the drying energy amount is 1/5), and the first transparent resin layer is added to the second transparent resin layer. Except for using the same melamine resin composition as in Example 1,
・ <Fluorescent ink composition>
Lumilite nano RY202 (particle size 30 nm) 5 parts by mass Isopropyl alcohol 50 parts by mass Water 45 parts by mass A hologram sheet A ′ of the present invention was produced.
The phosphors were formed in the concave portion with a bias from the convex portion of the hologram relief.
When observed in the same manner as in Example 1, a clearer hologram reproduction image than that in Example 2 could be confirmed. Furthermore, the hologram sheet A ′ is quite highly transparent, and has the unexpectedness that a hologram appears from the hologram sheet A ′.
Example 4
After forming the hologram forming layer 2, a 3 μm coating film (before drying) is formed by a gravure coating method with a solvent having the following composition, and only the quick-drying component is volatilized.
・ <Solvent composition>
Cyclohexanone 1 part by weight Methyl ethyl ketone 40 parts by weight Cyclohexane 59 parts by weight The phosphor is sprinkled as it is in powder form (the hologram forming surface 2 is faced down and sprayed since the powder is formed) to form a fluorescent layer 3, Except for drying, volatilizing the remaining solvent, and applying a polyvinyl chloride / vinyl acetate resin composition (n = 1.54) as a second transparent resin layer thereon. In the same manner as in Example 2, the hologram sheet A of the present invention was produced.
When observed in the same manner as in Example 2, the same effect as in Example 2 was obtained, but the transparency of the hologram sheet was higher than that in Example 2, and the hologram sheet was observed as a substantially transparent sheet. It was rich in the unexpected that a hologram image floats from the inside, and the hologram reproduction image could be confirmed as a hologram reproduction image with clearer and strong fluorescence intensity.

Comparative example

A hologram sheet was formed without forming a fluorescent layer, and was used as a comparative example.
When observed in the same manner as in Example 1, it was not possible to confirm a hologram reproduction image that can be visually recognized.
From this, it was possible to determine that the hologram sheet was not genuine and the passport was fake.

A, A ′ Hologram sheet 1 Transparent substrate 2 Transparent resin layer having hologram relief (first transparent resin layer: hologram forming layer)
3 Fluorescent layer (continuous or partial formation)
4 Second transparent resin layer 5 Example of observation state: Visible light (illumination light)
6 Same as above: No reproduced image 7 Same as above: Ultraviolet light (illumination light)
8 Same as above: Green reproduction image

Claims (4)

A transparent resin layer having a hologram relief including a diffraction grating group corresponding to a hologram image is provided on one surface of the transparent substrate, and a fluorescent layer is provided in contact with the hologram relief, and further on the transparent resin A hologram sheet, wherein a transparent resin layer having a difference in refractive index from the layer is within 0.3 is provided.
The fluorescent layer is formed with a uniform thickness following the unevenness forming the hologram relief, and a transparent resin layer having a refractive index difference with the transparent resin layer within 0.3 is provided thereon. The hologram sheet according to claim 1, wherein the hologram sheet is formed.

The fluorescent layer is formed only in the concave and convex recesses forming the hologram relief, and further, a transparent resin layer having a refractive index difference with the transparent resin layer within 0.3 is provided thereon. The hologram sheet according to claim 1, characterized in that:
The hologram sheet according to claim 2 or 3, wherein the fluorescent layer has a thickness of 0.01 µm or more and 0.3 µm or less.

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