JP4839789B2 - Organic inorganic composite material for 3D display - Google Patents

Description

  The present invention relates to an organic-inorganic composite material for a three-dimensional display device suitable for a display unit of a three-dimensional display device used in the medical field, architectural field, air traffic control system, molecular structure display, and the like.

  It is indispensable to handle three-dimensional information in many fields such as CT diagnosis and surgical simulation in the medical field, CAD in the building field, aircraft position display in air traffic control systems, and molecular structure display in science and technology calculations. Currently, CRT (CRT) displays, liquid crystal displays, electroluminescence displays, etc. are known as display devices capable of three-dimensional display, but since these displays can only display two-dimensional images, perspective methods are used. 3D display is made possible by the pseudo 3D display method. However, it is difficult for the pseudo three-dimensional display method to sufficiently display the three-dimensional information as described above. Therefore, there is a demand for a three-dimensional display device that displays a large amount of three-dimensional information at a high speed and can be observed freely from front and rear, left and right, and top and bottom.

In general, the physiological factors that cause a human to stereoscopically view an object are called (1) binocular parallax, (2) binocular congestion angle, (3) focus adjustment (crystal adjustment), and (4) monocular motion parallax. .
Conventionally, most of the methods used for three-dimensional display realize (1) binocular parallax, and must be accompanied by unnaturalness and extreme fatigue. It is also thought to be a cause of physiological diseases such as anomalies in stereoscopic perception. Recently, attempts have been made to superimpose a plurality of flat screens to satisfy (2) the binocular congestion angle, and (3) focus adjustment (adjustment of the lens), but this is not sufficient. Also, (4) monocular motion parallax has not yet been realized.

  A display device using holography is well known as a display device that displays a stereoscopic image more faithfully. Holography can satisfy the above three points: (1) binocular parallax, (2) binocular congestion angle, and (3) focus adjustment (crystal lens adjustment), but (4) monocular motion parallax. Realization is difficult. In addition, a display device using holography needs to perform optical writing and reproduction, and when displaying an electronic fictitious object, it is necessary to perform calculation of a huge amount of interference fringes. It is very difficult to display.

  Moreover, a volume scanning method (depth sampling method) is mentioned as a method which satisfies said (1)-(4). The volume scanning method is a method for displaying a complete three-dimensional image in a true sense, that is, it can be observed freely from front to back, left and right, and top and bottom. As for the volume scanning method, (a) varifocal mirror method, (b) moving display method, (c) moving screen method, and (d) up-conversion fluorescence method are known.

  The (a) varifocal mirror method is a method in which an image of a cathode ray tube or the like is reflected in synchronization with the movement of a mirror that vibrates back and forth. However, an oscillating mirror changes the magnification of the image and requires correction. In addition, there is a limit to the size that can be expressed and the range in which the image can be seen.

  The (b) moving display system displays a stereoscopic image by moving and rotating a light emitting diode display or the like displaying a cross-sectional view of a stereoscopic image at high speed. Further, the above (c) moving screen method is to make a moving image appear three-dimensionally by drawing a cross-sectional view of a three-dimensional image with a laser beam on a moving screen. However, these methods have a problem that the range in which a stereoscopic image can be seen is limited depending on the direction of movement, and the resolution is different. In addition, the structural member of the three-dimensional display device must be included in the display unit, and the image tends to become unclear basically.

The above (d) up-conversion fluorescence method uses the up-conversion phenomenon of the phosphor, and particularly uses the up-conversion phenomenon due to two-stage absorption to cause the phosphor to emit light along the actual light emitting surface, thereby producing a three-dimensional image. Is displayed.
Recently, a fluorescent glass deposited on a fluoride glass is used as a display unit, and laser beams of two different wavelengths are incident on the display unit from different directions to intersect at one point, and only that one point is emitted. A method has been proposed (see, for example, Non-Patent Document 1). In this method, a three-dimensional image can be displayed because the light emission point moves by scanning in the horizontal and vertical directions while synchronizing the respective laser beams.
However, the display unit is formed by depositing a phosphor on fluoride glass, and it is difficult to manufacture a large display unit. Moreover, there is a possibility that the emission color may be affected by the composition of the fluoride glass, and the target emission color may not be obtained. Furthermore, in order to display a stereoscopic image with a plurality of emission colors, that is, to display a stereoscopic image in color, a phosphor that emits only three primary colors of monochromatic light is selected, and a fluoride glass on which each phosphor is deposited is selected. It is necessary to manufacture and laminate these to form a display portion, and the manufacturing process is complicated. For this reason, it has not reached practical use.

Therefore, in order to solve the above problems, the present inventor has developed a three-dimensional display device in which phosphor fine particles that are excited by two or more types of light having different wavelengths to emit up-conversion light are dispersed in a transparent liquid or a transparent resin. A phosphor fine particle dispersion was proposed. When this phosphor fine particle dispersion for a three-dimensional display device is used in a display device, a stereoscopic image can be displayed by utilizing an up-conversion phenomenon due to two-stage absorption. In addition, the transparent liquid and the transparent resin can be arbitrarily selected, and the influence of the medium on the emission color can be avoided. Furthermore, compared with the thing of said nonpatent literature 1, it can manufacture easily and the enlargement is also attained.
However, when producing a display part by this method, first, phosphor fine particles are synthesized, classified to obtain phosphor fine particles having a uniform particle diameter, and the obtained phosphor fine particles are kneaded into a transparent resin. Thus, the manufacturing process becomes complicated, and the manufacturing process is simple compared with the display unit described in Non-Patent Document 1 described above, but problems still remain.

  Patent Document 1 discloses an organic inorganic material containing an organic resin, an aluminum compound, and a rare earth element in order to solve the problem that rare earth elements easily aggregate when an organic resin and a rare earth compound are mixed. Composite materials have been proposed. This organic-inorganic composite material is excellent in dispersibility of rare earth elements. However, Patent Document 1 relates to an organic-inorganic composite material applied to an optical material such as a lens, and does not describe any three-dimensional display device.

JP 2005-76002 A "A Three-Color, Solid-State, Three-Dimensional Display" Elizabeth Downing, Lambertus Hesselink, John Ralston, Roger Macfarlane, p.1185-1188, SCIENCE, Vol. 273, 30 August 1996

  The present invention has been made in view of the above problems, and is capable of upconversion light emission, can be increased in size, and can be easily manufactured. Organic-inorganic composite material for 3D display device and 3D display device The main purpose is to provide

  To achieve the above object, the present invention includes an organic resin, an aluminum compound, and a rare earth element, and is characterized in that it emits up-conversion light when excited by two or more different wavelengths of light. An organic-inorganic composite material for a display device is provided.

  When the organic-inorganic composite material for a three-dimensional display device of the present invention is used for a display device, a stereoscopic image can be displayed by utilizing an up-conversion phenomenon due to two-stage absorption. Such an organic-inorganic composite material for a three-dimensional display device can be manufactured, for example, by mixing an organic resin, a raw material of an aluminum compound, and a rare earth compound. Is possible. Further, the organic resin used in the present invention can be arbitrarily selected, and it is possible to avoid the influence of the light emission color due to the composition of the material, and it is possible to obtain the target light emission color.

  In the above invention, the rare earth element is erbium (Er), holmium (Ho), praseodymium (Pr), thulium (Tm), neodymium (Nd), gadolinium (Gd), europium (Eu), samarium (Sm), It is preferably at least one selected from the group consisting of terbium (Tb), dysprosium (Dy) and cerium (Ce). This is because these are preferable as rare earth elements capable of up-conversion emission.

  The organic-inorganic composite material for a three-dimensional display device of the present invention may further contain ytterbium (Yb). This is because ytterbium (Yb) has good sensitivity to light and can be used as a sensitizer.

  Moreover, the organic-inorganic composite material for a three-dimensional display device of the present invention may exhibit a plurality of emission colors. In a 3D display device using such an organic-inorganic composite material for a 3D display device, color display is possible.

  Furthermore, the present invention provides a display unit having the above-described organic-inorganic composite material for a three-dimensional display device, two or more infrared light sources arranged around the display unit, and light emitted from the infrared light source. There is provided a three-dimensional display device comprising control means for controlling a direction.

  According to the present invention, since the organic-inorganic composite material for a three-dimensional display device described above is used for the display unit, the display unit can be enlarged. In addition, since the organic resin can be arbitrarily selected in the organic-inorganic composite material for a three-dimensional display device as described above, it is possible to prevent the emission color from being affected by the composition of the material.

  The organic-inorganic composite material for a three-dimensional display device of the present invention can be increased in size and can be easily manufactured by a simple process. Further, the organic resin can be arbitrarily selected, and it is possible to avoid the influence of the emission color of the up-conversion emission depending on the composition of the material, so that the desired emission color can be obtained.

  Hereinafter, the organic-inorganic composite material for a three-dimensional display device and the three-dimensional display device of the present invention will be described in detail.

A. Organic-inorganic composite material for three-dimensional display device The organic-inorganic composite material for three-dimensional display device of the present invention (hereinafter sometimes referred to as organic-inorganic composite material) contains an organic resin, an aluminum compound, and a rare earth element. In addition, it is characterized in that it emits up-conversion light when excited by light of two or more different wavelengths.

General up-conversion light emission will be described with reference to the drawings. FIG. 1 shows an example in which erbium (Er) is used as a rare earth element and infrared light of 1500 nm and 850 nm is irradiated as excitation light. First, as shown in FIG. 1A, erbium is excited by the excitation light of 1500 nm and _moves from ¹ I _15/2 to ¹ I _13/2 having a higher energy level. As shown in FIG. 1B, erbium is excited by 850 nm excitation light, and the energy level of erbium is further _increased from ¹ I _13/2 to ⁴ S _3/2 . Then, as shown in FIG. 1C, when the excited erbium returns to the ground state, light of 545 nm is emitted.

  Thus, upconversion light emission refers to a case where light excited at 1500 nm and 850 nm emits light having a higher energy of 545 nm, that is, light emitted at a higher energy than the excitation light.

  Since the organic-inorganic composite material of the present invention contains, for example, a rare earth element that generates such up-conversion light emission, it is not necessary to excite with high energy light such as ultraviolet light. In addition, since the organic-inorganic composite material is used in a three-dimensional display device, it is usually preferable that light emission is visible light. Therefore, in the case of up-conversion emission, light having a wavelength longer than that of visible light is used as excitation light. For this reason, the excitation light wavelength and the emission wavelength hardly overlap each other, and a good image display can be obtained.

The organic-inorganic composite material of the present invention emits up-conversion light when excited by two or more different wavelengths of light. That is, the organic-inorganic composite material is excited by two excitation light of the infrared light 2 of the infrared light 1 and the wavelength lambda ₂ wavelength lambda ₁ as illustrated in FIG. 2, emits light of wavelength lambda ₃ be able to.
As described above, the case where the light is excited through the energy level by two or more types of excitation light having different wavelengths and emits up-conversion light is referred to as up-conversion light emission by two-stage absorption in the present invention.

A three-dimensional display device using the organic-inorganic composite material exhibiting up-conversion light emission illustrated in FIG. 2 is shown in FIG. As illustrated in FIG. 3, the infrared light 15a having the wavelength λ ₁ (infrared light 1 in FIG. 2) is irradiated from one direction of the display unit 11 made of the organic-inorganic composite material of the present invention, and the wavelength from another direction. The infrared light 15b of λ ₂ (infrared light 2 in FIG. 2) is irradiated and crossed at one point. Then, the point 13 where the infrared light 15a (infrared light 1 in FIG. 2) and the infrared light 15b (infrared light 2 in FIG. 2) intersect emits light. This is because up-conversion emission exemplified in FIG. 2 occurs at this time. When the infrared light 15a and the infrared light 15b are scanned in the horizontal and vertical directions while synchronizing the infrared light 15a and the infrared light 15b, the light emission point 13 moves three-dimensionally, so that a three-dimensional image can be displayed.

  Conventionally, when an organic resin and a rare earth compound are mixed, there has been a problem that rare earth elements are difficult to uniformly disperse and aggregate, but in the present invention, an aluminum compound is added to the rare earth compound mixed with the organic resin. The rare earth compound can be uniformly dispersed, and a transparent organic-inorganic composite material can be obtained. The reason for this is not clear, but due to the presence of the aluminum compound, the rare earth compound or a part of the rare earth compound is substituted with an organic group such as a vinyl group. Is presumed to be uniformly mixed.

  The organic-inorganic composite material of the present invention can be produced, for example, by mixing an organic resin, an aluminum compound raw material, and a rare earth compound. Therefore, it can be easily manufactured by a simple process and can be enlarged. Furthermore, the organic resin to be used can be arbitrarily selected, and the influence of the light emission color by the composition of the material, such as the phosphor deposited on the fluoride glass described in the background art column, should be avoided. Can do. Therefore, it is possible to obtain a target emission color.

Further, when the organic-inorganic composite material of the present invention is applied to a three-dimensional display device capable of color display, for example, the organic-inorganic composite material containing each rare earth element exhibiting upconversion emission at wavelengths corresponding to the three primary colors And it is sufficient. Therefore, it is possible to easily obtain an organic-inorganic composite material that can be used for a three-dimensional display device for color display.
Hereinafter, each component of the organic-inorganic composite material of the present invention will be described.

1. Rare earth element The organic-inorganic composite material of the present invention contains a rare earth element. This is because many rare earth elements have a plurality of energy levels in an excited state and are suitable as those that are excited by two or more types of light having different wavelengths and emit up-conversion light.

  The rare earth element used in the present invention is not particularly limited as long as it is excited by light of two or more different wavelengths and emits up-conversion light. In general, rare earth elements that are trivalent ions can be mentioned, among which erbium (Er), holmium (Ho), praseodymium (Pr), thulium (Tm), neodymium (Nd), gadolinium (Gd), europium. (Eu), samarium (Sm), terbium (Tb), dysprosium (Dy) and cerium (Ce) are preferably used. These rare earth elements may be used alone or in combination of two or more.

As examples of the up-conversion emission of the rare earth element, FIGS. 4A to 4C show up-conversion emission of praseodymium (Pr), erbium (Er), and thulium (Tm), respectively. Although not shown, for example, when erbium (Er) is irradiated with light of 970 nm or 1500 nm as excitation light, it undergoes an up-conversion process, and at the energy level of Er ³⁺ ions, 410 nm ( ² H _9/2 − _{^{4 I 15/2), 545nm (4}} S 3/2 - 4 I 15/2), 660nm (4 F 9/2 - shows visible light emission, such as _{4 I 15/2).}

  The content of the rare earth element in the organic-inorganic composite material varies greatly depending on the type of the rare earth element and the required degree of light emission, and is appropriately adjusted according to the application of the present invention.

In order to introduce a rare earth element into the organic-inorganic composite material of the present invention, for example, a water-soluble rare earth compound such as an inorganic acid salt such as a rare earth chloride or nitrate, or an organic acid salt such as an acetate can be used. By using a water-soluble rare earth compound, an arbitrary amount of rare earth elements can be introduced.
When a metal salt is used to introduce a rare earth element, alcohol, glycol, acetic acid, acetylacetonate, etc. are added to the metal salt solution in order to disperse the metal salt in the organic resin without agglomerating the metal salt. May be. Among these, acetic acid, acetylacetonate, and the like form a complex with a metal salt, and thus are effective when a rare earth element is contained at a high concentration.

2. Aluminum compound As a raw material of the aluminum compound used in the present invention, for example, an alkoxide represented by Al (OR ¹ ) ₃ (R ¹ represents an alkyl group), (R ² O) _3-n AlL _n (R ² Represents an alkyl group, n = 1 to 2, L represents a ligand, and is an alkoxide derivative represented by acetylacetona group, ethoxyacetylacetona group, etc.), Al (NO ₃ ) and metal salts such as ₃ · 9H ₂ O and the like.

  Further, boehmite sol can be used as a raw material for the aluminum compound. Here, the boehmite sol is a sol containing a substance (particle) represented by the molecular formula of AlO (OH), and amorphous aluminum obtained by hydrolyzing the above alkoxide, alkoxide derivative, or metal salt. It includes particles that can be easily peptized and obtained by a method such as heating immediately after hydrolysis of monohydroxide. Since boehmite sol has aluminum or a hydroxyl group, it easily forms a covalent bond or a hydrogen bond with an organic resin component at room temperature, and has good dispersibility. In addition, when an alkoxide such as aluminum isopropoxide or a derivative thereof is used when preparing boehmite sol, the alkoxide or the derivative thereof has an Al—O bond as a molecular structure from the beginning, so that it is easily crosslinked and dispersed. The property can be further improved.

The boehmite sol can be prepared by hydrolyzing the alkoxide, alkoxide derivative, or metal salt. Specifically, an aqueous solution mainly containing relatively high temperature water of 10 ° C. or more and less than 100 ° C., preferably 50 ° C. to 90 ° C. is added to the above alkoxide, alkoxide derivative, or metal salt, Stirring is performed for 1 hour or more, preferably 10 hours to 100 hours in an oil bath of 200 ° C. or less, preferably 50 to 100 ° C. At this time, reflux heating may be performed. As the amount of water to be used, it is preferable to use a relatively large amount of water in a molar ratio of 20 to 500 with respect to the above alkoxide, alkoxide derivative, or metal salt.
In addition, boehmite sol can be prepared by hydrolyzing the alkoxide, alkoxide derivative, or metal salt, and adding an acid to peptize.
By the above-described operation, the aluminum hydroxide is peptized to be converted into uniform fine particles, and a sol containing boehmite with low viscosity can be obtained. The concentration of boehmite contained in the sol is preferably 1 × 10 ⁻⁶ mol / l or more, more preferably 1 × 10 ⁻⁴ mol / l or more.

  Further, when producing boehmite, a boehmite sol containing a rare earth element at a high concentration can be obtained by using an aqueous solution in which a rare earth compound is previously dissolved in relatively high temperature water.

  In the case of using boehmite sol, since water is present in excess, compatibility with the organic resin may be deteriorated. In this case, it is preferable to replace the aqueous solvent in the boehmite sol with an organic solvent after preparing the boehmite sol. For example, boehmite that can be easily mixed with organic resin components by continuously substituting with an alcohol such as methanol or n-propanol at about 20 ° C. under reduced pressure using an evaporator and removing water in the boehmite sol. Fine particles can be obtained.

Furthermore, in the present invention, rare earth-containing alkoxides or derivatives thereof can be used as raw materials for aluminum compounds and rare earth elements. The rare earth-containing alkoxide and derivatives thereof have the rare earth-aluminum double alkoxide structure illustrated in FIG. 5 and have the advantage that they can be added directly to the organic resin. In FIG. 5, RE represents a rare earth element, Al represents aluminum, O represents oxygen, and R ³ represents an organic group. The organic group R ³ is preferably a functional group compatible with an organic resin, or a functional group capable of polymerizing with a monomer that is a raw material of the organic resin. Specifically, a vinyl group, an epoxy group, or an alkylsilyl is terminated at the terminal. And a functional group having a group or the like. Specific examples of the organic group R ³ are shown below.

3. Organic resin The organic resin used in the present invention is preferably one that does not affect up-conversion light emission, specifically, one that does not significantly reduce the light emission intensity. Specific examples include acrylate resins, polyolefins, polystyrenes, polycarbonates, ABS resins, polyesters, epoxies, unsaturated esters, acrylates, urethanes and ethers. Especially, what can be added in a monomer state as an organic resin raw material is used preferably.

  Examples of the monomer used as the raw material for the organic resin include vinyl monomers. Examples of vinyl monomers include methacrylic acid esters such as methyl methacrylate, acrylic acid esters, aromatic vinyl monomers such as methacrylic acid and styrene, vinyl cyanide monomers such as acrylonitrile, acrylic acid, and maleic acid. , Maleic acid esters, itaconic acid, itaconic acid esters, N-alkylmaleimides, N-phenylmaleimide (PMI) s and the like.

  Preferred monomers include methyl methacrylate, ethyl methacrylate, propylene methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, phenyl methacrylate and other methacrylic acid alkyl esters; methyl acrylate, ethyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, Acrylic acid alkyl esters such as 2-ethylhexyl acrylate, cyclohexyl acrylate, dodecyl acrylate, phenyl acrylate, and benzyl acrylate; side chain alkyl-substituted styrene such as styrene and α-methylstyrene, nuclear alkyl-substituted styrene such as vinyltoluene, bromostyrene, Halogenated styrene such as chlorostyrene, vinyl naphthalene, etc. Group vinyl monomer; acrylonitrile, methacrylonitrile, fumaronitrile, maleonitrile, such as vinyl cyanide monomers such as α- chloro acrylonitrile. Furthermore, maleic acid, maleic acid esters, itaconic acid and itaconic acid esters, N-alkylmaleimides, N-phenylmaleimides (PMI) s and the like are also preferable.

4). Other components The organic-inorganic composite material of the present invention may contain ytterbium (Yb). This is because ytterbium (Yb) has a good sensitivity to light and functions as a sensitizer.
Here, a system using the above-described rare earth element that is excited by light of two or more different wavelengths and emits up-conversion light and ytterbium (Yb) will be described. When ytterbium is excited, energy is generated, and the energy generated by the excitation of ytterbium may be able to push up the energy level of the rare earth element in some cases. This is because energy transfer can occur when the energy level of ytterbium is close to the energy level of the rare earth element. Therefore, for example, when two types of excitation light having different wavelengths are used, one excitation light can be ytterbium excitation wavelength light, and the other excitation light can be excitation light of a rare earth element. In this case, since ytterbium has good sensitivity to light, it is possible to efficiently perform up-conversion light emission.

  In the present invention, the organic-inorganic composite material may contain silica, titania, zirconia and the like for the purpose of improving water absorption and hardness. As these raw materials, alkoxides and derivatives thereof can be used. For example, when silica is contained, tetraethoxysilane, methyltriethoxysilane, 2-hydroxyethyl methacrylate (HEMA), those having a vinyl group, or those having an ethylene oxide group may be used as a raw material for silica. it can. Since 2-hydroxyethyl methacrylate has a hydrophilic group and forms hydrogen bonds and the like with boehmite sol, the affinity with boehmite sol is good.

  Furthermore, when producing an organic-inorganic composite material, a polymerization initiator such as a polymerization initiator, a molecular weight regulator, a dispersant, and other solvents are added to polymerize monomers that are raw materials for organic resins. Can do. As a polymerization initiation method, any of a heating method and a method of adding a polymerization initiator can be employed.

Examples of the polymerization initiator include organic peroxides and azo compounds, and these polymerization initiators can be used together with an emulsifier and a surfactant.
Specific examples of the azo compound include 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2′-methylbutyronitrile), and 1,1′azobis (cyclohexane-1-carbohydrate). Nitriles) and the like. Examples of the organic peroxide include peroxyesters such as t-hexylperoxyisopropyl monocarbonate and t-hexylperoxy-2-ethylhexanoate; diacyl peroxides such as lauroyl peroxide; Peroxyketals such as 1-bis (t-hexylperoxy) 3,3,5-trimethylcyclohexane; and the like.

  The molecular weight modifier is used for controlling the fluidity of the organic resin in the polymerization. Specifically, mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan; monoterpenoids such as 1-methyl-4-isopropylidenecyclohexene; 2,4-diphenyl-4-methyl-1 'Styrene dimers such as pentene;

  Moreover, you may add antioxidant, a ultraviolet absorber, a coloring inhibitor, an antistatic agent, a fluorescent paint, a mold release agent, another stabilizer, etc.

5). Organic-inorganic composite material The organic-inorganic composite material of the present invention can be excited by light of two or more different wavelengths to emit up-conversion light, and is excited by light of a wavelength within a predetermined range. There is no particular limitation as long as it is present. In a three-dimensional display device using such an organic-inorganic composite material, a three-dimensional image can be displayed by utilizing an up-conversion phenomenon due to two-stage absorption of the organic-inorganic composite material.

  In addition, when the organic-inorganic composite material of the present invention is applied to a three-dimensional display device capable of color display, the organic-inorganic composite material preferably exhibits a plurality of emission colors. In this case, it is particularly preferable to exhibit the three primary colors of red, green, and blue. For example, a plurality of emission colors can be obtained by using an organic-inorganic composite material containing a plurality of rare earth elements.

At this time, it is preferable that the plurality of rare earth elements contained in the organic-inorganic composite material are excited by light of different wavelengths and emit up-conversion light. In the three-dimensional display device using the organic-inorganic composite material of the present invention, the light emission point is moved three-dimensionally, for example, by scanning two infrared lights, so that it is excited by light of substantially the same wavelength and emits up-conversion light. This is because when a plurality of rare earth elements are used, it is difficult to move the light emission points of the respective colors separately.
In order to excite one kind of rare earth element for upconversion emission, as described above, two or more kinds of infrared light having different wavelengths are irradiated, so that the excitation light used for upconversion emission of each rare earth element. It is preferable that the wavelengths are different from each other. Specifically, the difference is preferably ± 5 nm or more, more preferably ± 10 nm or more.
As described above, when the organic-inorganic composite material of the present invention is applied to a three-dimensional display device capable of color display, the type of the rare earth element is appropriately selected in consideration of the wavelength of the excitation light that causes the rare earth element to up-convert light emission. Is done.

  The range of the wavelength of the excitation light that causes the rare-earth element to up-convert light emission is preferably in the infrared region, and is at least a wavelength in the range of 700 nm to 2000 nm, and more preferably in the range of 700 nm to 1800 nm, particularly 800 nm to 1600 nm. A wavelength within the range is preferred.

The organic-inorganic composite material of the present invention is preferably transparent. This is because if the organic-inorganic composite material is opaque, the display quality may deteriorate when used in a three-dimensional display device. Specifically, the average transmittance in the visible region of the organic-inorganic composite material is preferably 50% or more, more preferably 60% or more, and most preferably 70% or more.
The average transmittance is a value measured by using a UV-3100 manufactured by Shimadzu Corporation in the range of a wavelength of 380 nm to 800 nm by producing a molded product having a thickness of 1 mm using an organic-inorganic composite material. Average value.

Furthermore, the organic-inorganic composite material preferably has a haze (cloudiness) of 50% or less, more preferably 40% or less, and most preferably 30% or less.
In addition, the said haze is the value which produced the 1 mm-thick molded article using the organic inorganic composite material, and measured based on JISK7105.

  In the organic-inorganic composite material of the present invention, an aluminum compound or a rare earth element introduced as a rare earth compound forms a coordinate bond or a hydrogen bond with an oxygen atom or the like in an organic resin, thereby removing excess water and solvent. After that, it remains in the organic resin.

B. 3D Display Device Next, the 3D display device of the present invention will be described. A three-dimensional display device according to the present invention includes a display unit having the above-described organic-inorganic composite material, two or more infrared light sources arranged around the display unit, and a direction of light emitted from the infrared light source. And control means for controlling.

  FIG. 3 shows an example of the three-dimensional display device of the present invention. As shown in FIG. 3, the three-dimensional display device 10 of the present invention includes a display unit 11 made of an organic-inorganic composite material, and two infrared light sources 12 a and 12 b arranged around the display unit 11. ing. The infrared light sources 12a and 12b emit infrared light 15a and 15b having different wavelengths. Furthermore, the infrared light sources 12a and 12b are movable, and the direction of the infrared light 15a and 15b can be arbitrarily changed. In the three-dimensional display device 10, the means for moving the infrared light sources 12a and 12b is a control means for controlling the directions of the infrared lights 15a and 15b.

  When the infrared light 15a and 15b are irradiated to the display unit 11 from different directions by the infrared light sources 12a and 12b and the infrared light 15a and the infrared light 15b are crossed, the crossed point 13 emits light. This is because the rare earth elements contained in the organic-inorganic composite material are excited by infrared light 15a and 15b having different wavelengths, that is, excited by two-stage absorption, for example, as shown in FIG. Since the infrared light sources 12a and 12b are movable, the infrared light sources 12a and 12b are moved, and scanning in the horizontal and vertical directions while synchronizing the infrared light 15a and 15b is performed in the display unit 11. The light emitting point 13 can be moved back and forth, left and right, and up and down. Thereby, in the present invention, a stereoscopic image can be displayed.

  In the present invention, since the organic-inorganic composite material described above is used for the display unit, the display unit can be easily enlarged. Moreover, in this organic-inorganic composite material, since an organic resin can be arbitrarily selected, it is possible to avoid an influence on the emission color by the composition of the material.

Furthermore, in the case of a three-dimensional display device capable of color display, it is necessary to prepare a material so that a plurality of emission colors can be obtained, but in the present invention, a plurality of rare earth elements are contained, An organic-inorganic composite material exhibiting a luminescent color is used, or a plurality of organic-inorganic composite materials containing a single rare earth element and exhibiting a single luminescent color may be used. The display portion can be easily obtained by a simple process.
Hereinafter, each configuration of the three-dimensional display device of the present invention will be described.

1. Display unit The display unit used in the present invention has an organic-inorganic composite material.
Since the organic-inorganic composite material itself is in a solid state, the display unit is usually made of an organic-inorganic composite material. For example, a display portion made of an organic-inorganic composite material can be produced by a molding method such as photocuring, press molding, or injection molding.
The size of the display unit is not particularly limited, and is appropriately selected depending on the application.

  In the present invention, when a three-dimensional display device capable of color display is used, an organic-inorganic composite material containing a plurality of rare earth elements and exhibiting a plurality of emission colors is used, or one kind of rare earth element is contained. It is preferable to use a plurality of organic-inorganic composite materials that exhibit a single emission color.

In the case where a plurality of organic-inorganic composite materials containing one kind of rare earth element and exhibiting a single emission color are used, each organic-inorganic composite material preferably exhibits three primary colors of red, green, and blue emission colors. In this case, the rare earth element contained in each organic-inorganic composite material is preferably one that is excited by light of different wavelengths and emits up-conversion light. In the three-dimensional display device of the present invention, for example, since the light emitting point is moved three-dimensionally by scanning two infrared lights, when using a plurality of rare earth elements that are excited by light of substantially the same wavelength and emit up-conversion light, This is because it is difficult to move the light emission points of the respective colors separately.
In order to excite one kind of rare earth element for upconversion emission, as described above, two or more kinds of infrared light having different wavelengths are irradiated, so that the excitation light used for upconversion emission of each rare earth element. It is preferable that the wavelengths are different from each other. Specifically, the difference is preferably ± 5 nm or more, more preferably ± 10 nm or more.

The organic-inorganic composite material containing a plurality of rare earth elements and exhibiting a plurality of emission colors has been described in the above section “A. Organic-inorganic composite material”, and thus description thereof is omitted here.
The organic-inorganic composite material is the same as that described in the above section “A. Organic-inorganic composite material”, and the description thereof is omitted here.

2. Infrared light source At least two infrared light sources are required for the present invention, and are arranged around the display unit to emit infrared light.

  The number of infrared light sources is not particularly limited as long as it is two or more, but is usually an even number. In the present invention, since the phenomenon of up-conversion light emission due to excitation by two-stage absorption is often used, for example, two infrared light sources are required to obtain light emission of one color, and light emission of three colors is obtained. For this purpose, six infrared light sources are required. This infrared light source emits only infrared light having one wavelength.

  Further, the light source is not particularly limited as long as it emits infrared light, and for example, a semiconductor laser or the like can be used. For example, as shown in FIG. 6, the infrared light sources 12a and 12b may be a laser array in which a plurality of semiconductor lasers are arranged in an array.

  Moreover, since the three-dimensional display device of the present invention emits the intersection 13 of each infrared light 15a, 15b emitted from two infrared light sources 12a, 12b, for example, as shown in FIG. It is preferable to arrange the infrared light sources 12a and 12b so that the directions of the infrared lights 15a and 15b are not linear. This is because when the directions of the infrared light 15a and 15b are in a straight line, the portion where the infrared light 15a and 15b intersect emits light, and thus light emission is observed in a linear shape. Therefore, when scanning in the horizontal and vertical directions while synchronizing the infrared lights 15a and 15b, it is preferable to scan so that the directions of the infrared lights 15a and 15b are not in a straight line.

3. Control Unit The control unit in the present invention is not particularly limited as long as it controls the direction of light emitted from the infrared light source. The control means may control the directions of the infrared light 15a and 15b by moving the infrared light sources 12a and 12b as shown in FIG. 3, for example, and for example, as shown in FIG. The mirrors 16a and 16b may be disposed in the vicinity of the light sources 12a and 12b, and the directions of the infrared lights 15a and 15b may be controlled by changing the angles and positions of the mirrors 16a and 16b.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

Hereinafter, the present invention will be specifically described with reference to examples.
[Example 1]
An organic-inorganic composite material was produced at a blending ratio of 10 mol% Er ₂ O ₃ , 10 mol% Al ₂ O ₃ , and 80 mol% methyl methacrylate.
Aluminum isopropoxide: 1 mol part, erbium acetate 1.5 hydrate: 1 mol part dissolved in 400 mol part of water was added to 80 ° C warm water for hydrolysis, then 1N nitric acid was added. Further, the mixture was stirred at 80 ° C. for 76 hours to peptize to prepare a boehmite sol containing erbium.

Next, the boehmite sol was refluxed at 55 ° C. for 24 hours with a vacuum evaporator to remove water. Methyl methacrylate (MMA) and an ultraviolet curing agent (Irgacure 500 manufactured by Ciba Specialty Chemicals) were added and mixed with the resulting boehmite sol at a molar ratio of erbium of 1: 8.
The obtained liquid mixture was transferred to an ultraviolet light transmissive mold, purged with nitrogen to remove oxygen, irradiated with an ultraviolet lamp having an irradiation intensity of 0.6 W / cm ² for 24 hours, and then 2 ° C. to 140 ° C. An organic-inorganic composite material was obtained by maintaining the temperature for 2 hours after raising the temperature at / min.

[Example 2]
An organic-inorganic composite material was prepared at a blending ratio of 1 mol% Er ₂ O ₃ , 1 mol% Al ₂ O ₃ , and 98 mol% methyl methacrylate.
A boehmite sol containing erbium was produced in the same manner as in Example 1.
Next, the boehmite sol was refluxed at 55 ° C. for 24 hours with a vacuum evaporator to remove water. Methyl methacrylate (MMA) and an ultraviolet curing agent (Irgacure 500 manufactured by Ciba Specialty Chemicals) were added and mixed with the obtained boehmite sol at a molar ratio of erbium of 1:98.
And it carried out similarly to Example 1, and obtained the organic inorganic composite material.

[Example 3]
An organic-inorganic composite material was prepared at a blending ratio of 0.1 mol% Er ₂ O ₃ , 0.1 mol% Al ₂ O ₃ , and 99.8 mol% methyl methacrylate.
A boehmite sol containing erbium was produced in the same manner as in Example 1.
Next, the boehmite sol was refluxed at 55 ° C. for 24 hours with a vacuum evaporator to remove water. Methyl methacrylate (MMA) and an ultraviolet curing agent (Irgacure 500 manufactured by Ciba Specialty Chemicals) were added and mixed with the resulting boehmite sol at a molar ratio of erbium of 0.1: 99.8. did.
And it carried out similarly to Example 1, and obtained the organic inorganic composite material.

[Evaluation]
The organic-inorganic composite materials obtained in Examples 1 to 3 were irradiated so that two kinds of infrared lasers intersected. A semiconductor laser having a wavelength of about 860 nm was used as one infrared light laser, and a semiconductor laser having a wavelength of about 1550 nm was used as the other infrared laser. As a result, Er ³⁺ green emission near 550 nm was observed at the intersection of the two infrared lasers.

It is explanatory drawing for demonstrating upconversion light emission. It is explanatory drawing for demonstrating upconversion light emission. It is a perspective view which shows an example of the three-dimensional display apparatus of this invention. It is explanatory drawing for demonstrating upconversion light emission. It is a schematic diagram which shows the structure of rare earth containing alkoxide. It is a perspective view which shows the other example of the three-dimensional display apparatus of this invention. It is a perspective view which shows the other example of the three-dimensional display apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Three-dimensional display apparatus 11 ... Display part 12a, 12b ... Infrared light source 15a, 15b ... Infrared light

Claims (5)

  An organic-inorganic composite material for a three-dimensional display device, which contains an organic resin, an aluminum compound, and a rare earth element, and is excited by light of two or more different wavelengths to emit up-conversion light.   The rare earth elements are erbium (Er), holmium (Ho), praseodymium (Pr), thulium (Tm), neodymium (Nd), gadolinium (Gd), europium (Eu), samarium (Sm), terbium (Tb), The organic-inorganic composite material for a three-dimensional display device according to claim 1, wherein the organic-inorganic composite material for a three-dimensional display device is at least one selected from the group consisting of dysprosium (Dy) and cerium (Ce).   The organic-inorganic composite material for a three-dimensional display device according to claim 2, further comprising ytterbium (Yb).   The organic-inorganic composite material for a three-dimensional display device according to any one of claims 1 to 3, wherein the organic-inorganic composite material has a plurality of emission colors. A display unit comprising the organic-inorganic composite material for a three-dimensional display device according to any one of claims 1 to 4, and two or more infrared light sources arranged around the display unit, And a control means for controlling the direction of light emitted from the infrared light source.

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