JP6076804B2 - Method for producing phosphor-containing sheet - Google Patents

Description

  The present invention relates to a method for manufacturing a phosphor-containing sheet for converting the wavelength of light emitted from a light source such as an LED element, and a phosphor-containing sheet obtained by the manufacturing method.

  In recent years, LED lighting devices using light emitting diodes (LEDs) as light sources have been widespread as lighting devices instead of light sources such as incandescent bulbs and fluorescent lamps. As an LED lighting device, for example, it is suitable for illumination by mixing light of different colors such as blue light emitted from a blue LED element, red light emitted from a red LED element, and green light emitted from a green LED element. Lighting devices that emit white light such as daylight color, daylight white, white, warm white, or light bulb color are known.

  In order to obtain such white light at a low cost, the yellow phosphor is excited by the emission of one blue LED element to emit yellow light, and the blue light of the blue LED element and the yellow light of the yellow phosphor are emitted. White LED lighting devices that emit pseudo white light by mixing colors are also widely used. As yellow phosphors, YAG (yttrium, aluminum, garnet) phosphors are widely used. In addition, as a white LED illumination device using a blue LED element with improved color rendering properties and a YAG phosphor, a white LED illumination device to which a red phosphor or a green phosphor is further added is also known.

  As a method of color-converting the light emitted from the LED element with the phosphor, a method of dispersing the phosphor in a sealing body that seals the LED element of the LED lighting device is widely used. Specifically, for example, as in the LED lighting device 100 of FIG. 5, the light emitter housing member 5 and the LED element having a recess with an open top surface where a pair of leads 5 a and 5 b extending to the outside are arranged. 1, one electrode of the LED element 1 is connected to the lead 5 a, and the other electrode of the LED element 1 is wire-bonded by the gold wire 6 and connected to the lead 5 b, and is a recess that accommodates the LED element 1 In addition, an LED illuminating device having a configuration in which the LED element 1 is sealed by filling the resin sealing body 4 in which the phosphor 2a is dispersed in the transparent resin 2b can be given.

  In such an LED lighting device 100, the LED element 1 is sealed by potting and applying a liquid resin composition in which the phosphor 2a is dispersed in the transparent resin 2b to the concave portions little by little using a dispenser. In the manufacture of such an LED lighting device 100, the phosphor uniformly dispersed in the liquid resin composition has a difference in sedimentation with time according to the difference in mobility based on the difference in specific gravity and size. Therefore, there is a problem that dispersion of phosphors tends to vary in the sealing body due to non-uniform dispersibility. As a result, there has been a problem that uneven color of the luminescent color tends to occur in the luminescent region. Further, in industrial production, there is a problem in that the variation in emission color among individual LED lighting devices tends to increase, resulting in a decrease in yield.

  As a technique for solving such a problem, a phosphor-containing sheet molded in advance is used as a surface of an LED element, the inside or surface of a resin sealing body that seals the LED element, or a sealing body of an LED lighting device. There has also been known a method of disposing them at separate positions. FIG. 6 is a schematic cross-sectional view of an LED lighting device 110 in which a phosphor-containing sheet 12 in which a phosphor 2a is dispersed in a transparent resin 2b and formed into a sheet is disposed in a resin encapsulant 3 that encapsulates an LED element 1. FIG. In the LED lighting device 110, the phosphor 2 a in the phosphor-containing sheet 12 is excited by the light emission of the LED element 1 to emit fluorescence to perform color conversion.

  The phosphor-containing sheet is usually produced by preparing one phosphor-containing sheet in which phosphors are dispersed and cutting the phosphor-containing sheet into a size suitable for mounting on an LED lighting device. . When a phosphor-containing sheet is produced by such a method, the phosphor is changed over time in a coating solution prepared for application in order to produce by cutting a large phosphor-containing sheet produced in advance. It is possible to prevent the dispersibility from changing due to sedimentation. Such phosphor-containing sheets are conventionally produced by a casting method, a roll coating method, an extrusion laminating method, press molding, a spin coating method, or the like. In addition, Patent Document 1 below describes the phosphor dispersion stability by preparing a phosphor-containing sheet using a phosphor-containing resin composition having a viscosity of 500 Pa · sec or more at room temperature or a solid or semi-solid at room temperature. A technique for further improving the performance is disclosed.

JP2011-138985A

  When manufacturing a phosphor-containing sheet using means such as a casting method, roll coating method, press molding, extrusion laminating method, etc., control a sheet having a thin film thickness of, for example, 100 μm or less with high thickness accuracy. It was difficult. Further, even when a thin sheet having a thickness of 100 μm or less is manufactured by using the spin coating method, it is difficult to stably mass-produce a phosphor-containing sheet having an optically constant quality.

  As a result of investigations by various coating methods, the present inventors have found that an ink comprising a phosphor-containing resin composition using a so-called screen printing method in order to produce a thin phosphor-containing sheet controlled with high thickness accuracy. Was applied onto a support substrate, and a method of forming a coating film by leveling the applied ink was employed, and a phosphor-containing sheet was prepared by curing such a coating film.

  Each process of the manufacturing method of the fluorescent substance containing sheet using the screen printing method is demonstrated with reference to FIG. Fig.7 (a)-FIG.7 (e) are typical sectional drawings which show each process of a manufacturing method. In FIG. 7, 10 is a screen mesh having a mesh portion 10a, an opening 10b and a frame 10c, 11 is a supporting base material, 13a is a scraper, 13b is a squeegee, 24 is a liquid transparent resin in which phosphor particles are dispersed. The prepared ink 25 is a coating film formed by leveling the ink 24.

  In this manufacturing method, first, as shown in FIG. 7A, the screen mesh 10 is disposed above the support base material 11, and the ink 24 is placed on the screen mesh 10. Then, as shown in FIG. 7B, the ink 24 is filled in the opening 10b by spreading the ink 24 in the direction of the arrow with the scraper 13a. Then, after filling all the openings 10b with the ink 24, as shown in FIG. 7C, the squeegee 13b is moved in the direction of the arrow while being strongly pressed against the screen mesh 10 and the support base material 11, thereby FIG. The ink 24 is transferred to the support base 11 and printed as shown in FIG. Then, the ink is leveled so as to fill the gap between the inks by being left for a predetermined time. In this way, a coating film 25 of the ink 24 is formed on the support base 11 as shown in FIG. And the fluorescent substance containing sheet | seat is formed by hardening the coating film 25. FIG.

  And the fluorescent substance containing sheet | seat obtained by such a manufacturing method is cut | disconnected to the magnitude | size with which an LED illuminating device is mounted | worn, and LED as shown in FIG. 6 using the fluorescent substance containing sheet piece obtained in this way A lighting device can be manufactured.

  However, the LED lighting device obtained in this way also has a problem that it is easy to cause uneven color of the light emission color in the light emitting region. Moreover, in industrial production, the dispersion | variation in the luminescent color between the individual | organization | solid of several LED lighting apparatus cannot fully be reduced, and there existed a tendency for a yield not to improve. INDUSTRIAL APPLICABILITY According to the present invention, a phosphor-containing sheet is manufactured through a screen printing method, and the problem of causing uneven color of the emitted color can be suppressed when an LED lighting device is manufactured using such a phosphor-containing sheet. It aims at providing the manufacturing method of a fluorescent substance containing sheet, the fluorescent substance containing sheet obtained by the manufacturing method, and the fluorescent substance containing ink for screen printing used for the manufacture.

  As a result of detailed analysis of the phosphor-containing sheet obtained through the screen printing method in order to solve the above-described problems, the present inventors have obtained the following knowledge.

  FIG. 8A is a schematic view of the phosphor-containing sheet 12 of about 3 × 3 mm cut out from the thin phosphor-containing sheet obtained through the screen printing method, and the two portions thereof are enlarged and observed. The figure is shown. The phosphor-containing sheet 12 is formed by dispersing the phosphor 2a in the transparent resin 2b. As shown in FIG. 8 (a), the inventors of the present invention have a transparent region where the phosphor 2a is low in the region L indicated by the dotted line when the phosphor-containing sheet 12 is enlarged and observed. I noticed. And it was thought that the area | region where the existence ratio of such fluorescent substance 2a was low became the cause which produces the color nonuniformity of luminescent color in the light emission area | region of one LED lighting apparatus with the following mechanisms.

  FIG. 8B schematically shows the optical path when the phosphor-containing sheet 12 is attached to the LED illumination device. As shown in FIG. 8B, in such an LED lighting device, in the region L where the phosphor 2a is small, the wavelength conversion efficiency is low because the phosphor particles 2a are small, and the emission color of the LED element remains as it is. Make it easier to emit. Further, the light passing through this region is difficult to diffuse because it does not collide with the phosphor. As a result, uneven color tends to occur in the emission color obtained in one LED lighting device.

  The inventors of the present invention have studied the cause of the occurrence of such a region having a low ratio of phosphor particles, and have found that this region is formed along the mesh portion of the screen mesh. That is, when creating a thin sheet, phosphor particles having a large particle size and high specific gravity are difficult to move in the region where the screen mesh was present, and only the resin component that is easy to move flows. As a result, it was found that a region having a low phosphor content was easily formed. And as shown to Fig.8 (a), since the position of the area | region L has few fluorescent substance particles, color conversion efficiency and a diffusivity become lower than the surrounding area | region, and it has produced the color nonuniformity. Noticed. In particular, as the phosphor-containing sheet gets closer to the LED element, the color unevenness becomes more prominent, and in the case of an LED lighting device on which a convex lens is mounted, the color unevenness is enlarged by the lens and tends to appear prominently on the irradiated surface. there were.

  Moreover, since the position and area of the area | region L differ between the several LED illuminating device individual | organism | solids, it discovered that the dispersion | distribution of the luminescent color was produced between the individual | single_pieces of several LED lighting device. The present inventors diligently studied based on such knowledge and came to the present invention.

  That is, the production method of the present invention is a method for producing a phosphor-containing sheet by a screen printing method, and comprises 5 to 90% by mass of phosphor particles having an average particle diameter of 5 to 60 μm, and fine particles other than the phosphor particles. A phosphor-containing ink containing a liquid resin component; and applying the phosphor-containing ink on a support substrate through a screen mesh and leveling the applied phosphor-containing ink. A step of forming a film and a step of curing a coating film to form a cured film, wherein the fine particles are inorganic particles having an average particle size of 0.005 to 2 μm and resin particles having an average particle size of 0.5 to 20 μm It is a manufacturing method of the fluorescent substance containing sheet | seat containing at least one of these.

  FIG. 1 shows a schematic diagram when the phosphor-containing sheet 2 obtained by the production method according to the present invention is enlarged and observed. As shown in FIG. 1A, according to the manufacturing method of the present invention, inorganic particles having an average particle diameter of 0.005 to 2 μm are formed in a region L formed like a mesh mark of a screen mesh during leveling. In addition, fine particles containing at least one of resin particles having an average particle diameter of 0.5 to 20 μm can be present. The phosphor particles 2a having a large particle size such as an average particle size of 5 to 60 μm are difficult to flow in the area where the screen mesh was present during leveling, but the fine particles 2c as described above are transparent resin 2b. It can move following the flow.

  That is, as shown in FIG. 1C, for example, the liquid resin component includes 2a (Y) having a relatively large particle size as phosphor particles, 2a (R) having a relatively small particle size as phosphor particles, and In the case of using ink containing fine particles 2c that are easy to flow, such as resin particles having a specific gravity smaller than phosphor particles or inorganic particles having a small particle diameter, the fine particles 2c are the most liquid resin during leveling. The phosphor particles 2a (R) having a relatively small particle size can easily follow the liquid resin. Therefore, it is considered that many fine particles 2c that are most likely to flow in the region L can exist.

  In such a case, as shown in FIG. 1B, the light incident on the region L is reflected and diffused by the fine particles 2c. As a result, the light incident on the region L is diffused over a wide range in the phosphor-containing sheet 2, and the color is uniformly mixed. That is, when the fine particles are blended, the region L, which has a low phosphor content and is transparent, becomes an opaque or translucent region having diffusibility. As a result, the color unevenness of the light emitting region is suppressed regardless of the position and area ratio of the region L.

  As such fine particles, it is preferable that inorganic particles having an average particle diameter of 0.005 to 2 μm are contained from the viewpoint that the light transmittance of the phosphor-containing sheet is hardly lowered.

  In addition, the content ratio of fine particles in the phosphor-containing ink is 0.5 to 50% by mass, which suppresses the occurrence of color unevenness by imparting light diffusivity without significantly reducing the light transmittance. It is preferable because it can be performed.

  Moreover, it is preferable that the thickness of a coating film is 1-5 times the average particle diameter of fluorescent substance particle, and it is preferable that it is 10-100 micrometers. According to the present invention, even when a phosphor-containing sheet having a thin thickness close to the particle diameter of such phosphor particles is manufactured, an LED illumination device with little emission color unevenness can be obtained.

  Moreover, the process which further cut | disconnects a cured film to the dimension accommodated in a LED lighting apparatus, specifically, 10 * 10 mm or less, and also a dimension like 0.3 * 0.3 mm is further included. By using the phosphor-containing sheet that has been cut into small pieces in this way, it is possible to obtain an LED lighting device with little variation in emission color among individual LED lighting devices.

  As the liquid resin component, for example, a curable liquid silicone rubber or a curable liquid silicone resin is preferably included from the viewpoint of excellent heat resistance, light resistance, and light transmittance.

  The phosphor-containing sheet of the present invention comprises phosphor particles having an average particle size of 5 to 60 μm, 5 to 90% by mass, inorganic particles having an average particle size of 0.005 to 2 μm, and resin particles having an average particle size of 0.5 to 20 μm. It is a fluorescent substance containing sheet | seat containing 0.5-50 mass% of fine particles other than the fluorescent substance particle containing at least one, and silicone rubber or silicone resin, and thickness is 10-100 micrometers.

  Further, the thickness of the phosphor-containing sheet is preferably 1 to 5 times the average particle diameter of the phosphor particles. According to the present invention, even when a phosphor-containing sheet having a thin thickness close to the particle diameter of such phosphor particles is manufactured, an LED illumination device with little emission color unevenness can be obtained.

  In addition, the phosphor-containing ink for screen printing of the present invention contains 5 to 90% by mass of phosphor particles having an average particle diameter of 5 to 60 μm, fine particles other than the phosphor particles, and a liquid resin component. Is a phosphor-containing ink for screen printing containing at least one of inorganic particles having an average particle size of 0.005 to 2 μm and resin particles having an average particle size of 0.5 to 20 μm. As the liquid resin component, a curable liquid silicone rubber or a curable liquid silicone resin is preferably used.

  According to the present invention, when a phosphor-containing sheet having a thin film thickness is manufactured using a phosphor-containing ink containing phosphor particles and a liquid resin component through a screen printing process, the obtained phosphor-containing sheet is obtained. When an LED device is manufactured using a sheet, it is possible to obtain an LED lighting device with little color unevenness of light emission in one LED lighting device and little color variation among a plurality of LED lighting devices.

FIG. 1A is a schematic diagram when the phosphor-containing sheet 2 obtained by the manufacturing method according to the present invention is enlarged and observed, and FIG. 1B is a diagram in which the phosphor-containing sheet 2 is attached to the LED lighting device. FIG. 1C is an explanatory diagram for explaining the mobility of the ink forming component at the time of leveling. FIG. 2 is a schematic cross-sectional view of each step for explaining the method for producing a phosphor-containing sheet according to the present invention. FIG. 3 is a schematic cross-sectional view of the LED device 10 obtained using the phosphor-containing sheet of the present embodiment. FIG. 4 is a schematic cross-sectional view of the LED device 20 obtained using the phosphor-containing sheet of the present embodiment. FIG. 5 is a schematic cross-sectional view of a conventional LED lighting device 100. FIG. 6 is a schematic cross-sectional view of a conventional LED lighting device 110. FIG. 7 is a schematic cross-sectional view of each step for explaining a method for producing a phosphor-containing sheet that undergoes a screen printing step. FIG. 8A is a schematic view when the phosphor-containing sheet 12 obtained by the manufacturing method through the screen printing process is magnified and observed with a microscope, and FIG. 8B is a phosphor-containing sheet in the LED illumination device. An explanatory view schematically illustrating an optical path when 12 is mounted is shown.

  A method for producing the phosphor-containing sheet of the present embodiment will be described with reference to FIG. Fig.2 (a)-FIG.2 (e) are schematic cross sections which show each process of the manufacturing method of a fluorescent substance containing sheet. In FIG. 2, 10 is a screen mesh used in screen printing having a mesh portion 10a, an opening 10b and a frame 10c, 11 is a supporting substrate, 13a is a scraper, 13b is a squeegee, and 14 is a phosphor-containing ink. (Ink) and 15 are coating films formed by leveling the ink 14.

  In this production method, first, an ink for screen printing containing a phosphor used for coating film formation and fine particles other than the phosphor particles is prepared.

  As the liquid resin component, a curable liquid resin component that forms a transparent cured film by curing by heating, light irradiation, or the like or at room temperature is used. Specific examples thereof include silicone resins such as silicone rubber and silicone resin, fluorine resins, epoxy resins, acrylic resins, polyolefin resins, polyester resins, and polyurethane elastomers. Among these, since the silicone resin is excellent in heat resistance, light resistance, and light transmission, there is little deterioration such as discoloration due to long-term use, and it is easy to disperse the phosphor uniformly. preferable.

  The viscosity of the liquid resin component is not particularly limited, but is preferably 10 to 800 Pa · sec, more preferably 20 to 600 Pa · sec, and still more preferably 100 to 300 Pa · sec at normal temperature. The viscosity is a value measured by a “method using a single cylindrical rotational viscometer” in accordance with JIS K7117 at room temperature (25 ° C.).

Moreover, the kind and composition of the phosphor particles are not particularly limited, and are appropriately adjusted according to the target emission color. Specific examples of the types of phosphor particles, for _{example, Y 3-x Gd x Al} 5 O 12: Ce (0 ≦ x ≦ 3) in yttrium aluminate based fluorescent material represented (YAG), Ca-α- SiAlON: yellow phosphor such as _{Eu; CaS: Eu, CaAlSiN 3} : red phosphor such as Eu; formula _{AEu (1-x) Ln x} B 2 O 8 (a is Li, K, Na, and Ag A red phosphor represented by the general formula a (Sr), Ln is one selected from the group consisting of Y, La, and Gd, and B is W or Mo. _1-x Eu _{x (1-y)} Yb _xy ) O.SiO ₂ (where 2.9 ≦ a ≦ 3.1, 0.005 ≦ x ≦ 0.10, 0.001 ≦ y ≦ 0.1) Orange phosphors such as alkaline earth metal silicate phosphors represented by the formula, green phosphors represented by β-SiAlON: Eu, etc. And the like. These may be used alone or in combination of two or more.

The average particle diameter of the phosphor particles is 5 to 60 μm, preferably 10 to 40 μm. The phosphor particles having an average particle diameter of 5 to 60 μm may include particles having a particle diameter of 100 μm or more as secondary particles or single particles. Such large particles are caught on the screen mesh and screened. Since it tends to remain in the squeezed residual liquid that hardly passes through the mesh, it tends to be difficult to remain in the coating film. Therefore, when the coating film is formed by means of screen printing, there is also an advantage that coarse phosphor particles hardly remain on the coating film as compared with other coating methods. The average particle size is measured median value using a laser diffraction particle size distribution measuring apparatus (D _50).

  The content ratio of the phosphor particles in the ink is 5 to 90% by mass, preferably 30 to 70% by mass. When the content ratio of the phosphor particles is less than 5% by mass, color matching with the phosphor-containing sheet becomes difficult, and when the content ratio of the phosphor particles exceeds 90% by mass, the workability of screen printing decreases. Film formation becomes difficult.

  Fine particles other than phosphor particles are blended in the ink. The fine particles include at least one selected from inorganic particles having an average particle size of 0.005 to 2 μm and resin particles having an average particle size of 0.5 to 20 μm. In addition, since the inorganic particles are particles having a particle size smaller than that of the phosphor particles, they easily move following the liquid resin component during leveling. On the other hand, since resin particles have a small specific gravity, moderately large particles tend to move following the liquid resin component during leveling. Inorganic particles and resin particles may be used alone or in combination with inorganic particles and resin particles.

  The average particle diameter of the inorganic particles is preferably 0.005 to 2 μm, more preferably 0.01 to 1 μm. The kind of inorganic particles is not particularly limited, and specific examples thereof include silica, titanium oxide, calcium carbonate, aluminum oxide, talc, glass powder, and the like. Among these, fine particle silica, which is also referred to as nano silica, is particularly preferable. Further, the form of the inorganic particles is not particularly limited, but spherical particles are particularly preferable because they can easily follow the flow of the liquid resin component during leveling. These may be used alone or in combination of two or more.

  Moreover, it is preferable that the average particle diameter of a resin particle is 0.5-20 micrometers. The kind of the resin particles is not particularly limited, and specific examples thereof include, for example, silicone resin powder (average particle diameter of 0.5 to 10 μm), silicone rubber powder (average particle diameter of 1 to 20 μm), or composite powder thereof (average) Examples thereof include silicone resin particles such as a particle diameter of 0.5 to 20 μm and fluororesin powder (average particle diameter of 4 to 8 μm). In addition, since the resin particles usually have a small specific gravity and a shape close to a sphere, even if the average particle diameter is larger than that of the inorganic particles, the resin particles can easily follow the flow of the liquid resin component during leveling.

  The content ratio of fine particles in the ink is preferably 0.5 to 50% by mass, more preferably 1 to 10% by mass. When the content ratio of the fine particles in the ink is too high, the light transmittance tends to decrease, and when the content ratio of the fine particles is too low, the effect of diffusing light tends not to be sufficiently exhibited.

  The method for preparing the ink is not particularly limited. Specifically, for example, a method of sufficiently dispersing phosphor particles, fine particles, and liquid resin component blended so as to have a predetermined blend ratio using a known ink dispersion means such as a roll mill. Etc. Moreover, you may mix | blend the organic solvent as a diluent as needed in order to adjust the viscosity of an ink. Specific examples of the organic solvent include toluene, xylene, acetone, methyl ethyl ketone, hexane, and the like.

  The viscosity of the ink thus prepared is not particularly limited, but is preferably 200 to 1000 Pa · sec, more preferably 300 to 700 Pa · sec, and particularly preferably 400 to 700 Pa · sec at normal temperature. If the viscosity of the ink is too high, the coatability tends to decrease and leveling tends to take time. If the viscosity of the ink is too low, dripping becomes severe and it is difficult to form a coating film. Tend to be.

  In this manufacturing method, a coating film is formed by using a screen printing technique using the ink as described above. Specifically, first, as shown in FIG. 2A, an appropriate amount of ink 14 prepared in advance is placed on the screen mesh 10.

  The form of the screen mesh is not particularly limited as long as a coating film having a desired thickness can be formed. Specific examples thereof include, for example, a wire diameter of 20 to 70 μm, further about 25 to 60 μm, an opening of 30 to 250 μm, and further about 60 to 180 μm, and a screen thickness of 30 to 200 μm, A screen mesh having a mesh such as 40 to 100 μm is preferable.

  Then, as shown in FIG. 2B, the ink 14 is spread in the direction of the arrow by the scraper 13a to fill the opening 10b with the ink 14. Then, after all the openings 10b are filled with the ink 14, as shown in FIG. 2 (c), the squeegee 13b is moved in the direction of the arrow while being strongly pressed against the screen mesh 10 and the supporting base material 11, thereby FIG. The ink 14 is transferred to the support base 11 and printed as shown in FIG.

  The kind of support base material is not specifically limited. Specific examples thereof include, for example, a resin sheet mainly composed of a fluorine resin having a thickness of about 10 to 3000 μm, a polyester resin such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), and a polyolefin resin such as polyethylene and polypropylene. A glass plate, a metal plate, etc. are mentioned. The support substrate is particularly preferably a releasable resin sheet that has been subjected to a treatment for imparting releasability to the coating surface. Moreover, when thermosetting a coating film, the base material which has 100 degreeC or more heat resistance is preferable.

  Then, as shown in FIG. 2 (e), the applied ink 14 is allowed to stand for a predetermined time, so that the ink 14 is spread and leveled. In this way, the coating film 15 made of the ink 14 is formed on the support substrate 11.

  The thickness of the coating film formed by leveling is preferably 10 to 100 μm, more preferably 20 to 80 μm, and particularly preferably 30 to 60 μm. By forming a coating film having such a thin film thickness, a phosphor-containing sheet that can be accommodated in a small package LED lighting device can be obtained.

  Then, the phosphor-containing sheet is formed on the support substrate 11 by curing such a coating film 15. As the curing conditions, a heat curing process by heating, a light curing process by light irradiation, a room temperature curing process, or the like is appropriately selected according to the type of resin. The thickness of the phosphor-containing sheet is preferably 10 to 100 μm, more preferably 20 to 80 μm, and particularly preferably 30 to 60 μm.

  The phosphor-containing sheet thus obtained has a form obtained by, for example, placing and sealing the phosphor-containing sheet 2 as shown in FIG. 3 so as to cover the light emitting surface of the LED element 1. It is used for manufacturing the LED lighting device 10. FIG. 3 is a schematic cross-sectional view of an LED illumination device 10 in which a phosphor-containing sheet 2 in which a phosphor 2a and an inorganic filler 2c are dispersed in a transparent resin 2b is arranged in a resin encapsulant 3 that encapsulates an LED element 1. is there. In the LED lighting device 10, the wavelength of the light emitted from the LED element 1 is converted by exciting the phosphor 2 a in the phosphor-containing sheet 2 to emit fluorescence. In addition, when the phosphor-containing sheet 2 is arranged so as to be close to the LED element 1, color unevenness is easily enlarged, and thus the phosphor-containing sheet 2 is particularly arranged so as to be close to the LED element 1. In this case, the high effect of the present invention is achieved. Furthermore, in the case of an LED illumination device on which a convex lens is mounted, even if light from a light source is enlarged and irradiated, color unevenness does not occur on the irradiated surface, and the effect of the present invention is remarkably exhibited.

  In addition, the phosphor-containing sheet 2 obtained in this way as another form has, for example, the light emitting surface of the resin encapsulant 3 that seals the LED element 1 with the phosphor-containing sheet 2 as shown in FIG. You may use for manufacture of the LED lighting apparatus 20 of the form obtained by arrange | positioning so that it may cover. FIG. 4 is a schematic cross-sectional view of the LED lighting device 20 in which the phosphor-containing sheet 2 is disposed so as to cover the resin sealing body 3 that seals the LED element 1. In the LED lighting device 20, the light emission of the LED element 1 is wavelength-converted by exciting the phosphor 2a in the phosphor-containing sheet 2 to emit fluorescence.

  In addition, the obtained fluorescent substance containing sheet is cut | disconnected by the shape according to a use using a laser cutter, a cutting machine, a dicing saw etc., for example. Specifically, for example, when used for the LED illumination device 10 as shown in FIG. 3 or the LED illumination device 20 as shown in FIG. 4, 0.3 × 0.3 mm to 1.2 × 1. It is preferable to be cut to a dimension such as 2 mm. In addition, when used for a so-called chip-on-board (COB) LED lighting device in which one LED element is mounted on a substrate, it is preferable to cut the substrate to a size of about 0.3 × 0.3 mm. Even in the case of a COB LED lighting device, when a single sheet is placed on a plurality of LED elements, it is preferable to cut to a size of 10 × 10 mm. Moreover, when using for a power LED illuminating device, the dimension of 1 * 1-3 * 3mm may be sufficient as the length of one side.

  As LED elements, conventionally known LED devices that emit light in a wavelength region such as ultraviolet light, near ultraviolet light, visible light indicating wavelengths in the blue to red region, near infrared light, and infrared light are particularly limited. Used without. For example, blue LEDs include GaN-based, SiC-based; ZnS-based, ZnSe-based, and the like. Moreover, as green LED, GaP type; N type; GaP type etc. are mentioned. These may be used alone or in combination of two or more.

[Example 1]
130 parts by weight of yellow phosphor (YAG) having an average particle diameter of 30 μm, 5 parts by weight of silica having an average particle diameter of 0.01 μm, and 100 parts by weight of thermosetting liquid silicone rubber are mixed and kneaded after passing three times through an ink roll. As a result, an ink was obtained.

  Then, using the obtained ink, a coating film was formed on a release sheet made of fluororesin using a stainless screen mesh having a screen thickness of 90 μm so that the thickness after leveling was 50 μm. And after leveling the coating film on a release sheet, it heat-cured by heat-processing at 100 degreeC, and obtained the fluorescent substance containing sheet | seat of thickness 50micrometer and 100x100mm.

  The obtained phosphor-containing sheet was cut into a size of 1.2 × 1.2 mm to obtain 10 cut pieces. When the obtained cut piece was observed with a microscope, a highly transparent region was not observed. And in manufacture of the LED illuminating device of a form as shown in FIG. 4, ten pieces of LED illuminating devices which emit the white light were mounted by mounting the cut piece of the obtained phosphor-containing sheet on a blue LED element. As the blue LED element, an InGaN-based blue LED element having an emission peak wavelength (λp) of 470 nm was used. Then, 10 LED lighting devices were caused to emit light, and the emitted light was emitted toward the white plate to observe the uneven color of the irradiated surface. As a result, no color unevenness occurred on the irradiated surface. Also, the variation in emission color was small between phosphor-containing sheets obtained in different lots. The results are shown in Table 1.

[Example 2]
An ink was prepared in the same manner as in Example 1 except that the silica having an average particle size of 0.01 μm was replaced with a fluororesin having an average particle size of 0.8 μm, and a phosphor-containing sheet was prepared and evaluated. As a result, when the obtained cut piece was observed with a microscope, a highly transparent region was not observed. In addition, color unevenness did not occur on the irradiated surface. Also, the variation in emission color was small between phosphor-containing sheets obtained in different lots. The results are shown in Table 1.

[Example 3]
120 parts by mass of yellow phosphor (YAG) with an average particle size of 30 μm, 10 parts by mass of red phosphor with an average particle size of 10 μm, 5 parts by mass of silica with an average particle size of 0.01 μm, and 100 parts by mass of thermosetting liquid silicone rubber Then, the ink was obtained by kneading the ink roll three times. In Example 1, a phosphor-containing sheet was prepared and evaluated in the same manner as in Example 1 except that the ink prepared as described above was used instead of the ink of Example 1. As a result, when the obtained cut piece was observed with a microscope, a highly transparent region was not observed. In addition, color unevenness did not occur on the irradiated surface. Also, the variation in emission color was small between phosphor-containing sheets obtained in different lots. The results are shown in Table 1.

[Comparative Example 1]
An ink was prepared in the same manner as in Example 1 except that 105 parts by mass of silicone rubber was added without adding silica, and a phosphor-containing sheet was prepared and evaluated. As a result, when the obtained cut piece was observed with a microscope, many highly transparent regions were observed. In addition, among the 10 LED lighting devices, blue spot color unevenness occurred on the irradiated surface at different positions on the irradiated surface. The results are shown in Table 1.

[Comparative Example 2]
Ink was prepared in the same manner as in Example 1 except that glass beads having an average particle diameter of 30 μm were blended instead of silica, and a phosphor-containing sheet was prepared and evaluated. As a result, when the obtained cut piece was observed with a microscope, many highly transparent regions were observed. Further, on the irradiated surface, blue spot color unevenness occurred at different positions on the irradiated surface. The results are shown in Table 1.

[Comparative Example 3]
A phosphor-containing sheet was produced by spin coating using the ink obtained in Example 3. Specifically, an appropriate amount of the ink prepared in Example 3 was placed in the center of a flat disk having a diameter of 150 mm, and 1000 r. p. m. The coating film was formed by applying centrifugal force to the ink by rotating at a speed of 2 to 3 minutes. At this time, the YAG phosphor and the red phosphor were separated into a ring shape by centrifugal force when the coating film was formed. The coating film thus obtained was cured to prepare a phosphor-containing sheet. When this phosphor-containing sheet was used after being chopped, there was a large variation in emission color among LED lighting devices. In addition, there was a large variation in emission color among phosphor-containing sheets obtained by different spin coatings. The results are shown in Table 1.

[Comparative Example 4]
Using a uniaxial extrusion coater having a slit die having a die width of 200 mm, a die land of 5 mm, and a clearance of 50 μm, the ink having the composition of Example 1 was coated on a fluororesin-treated PET film to a thickness of 50 μm. However, coarse particles of the phosphor were caught on the die land, streaks were formed in the coating film, and the thickness in the flow direction became non-uniform. According to the extrusion coating method, it is difficult to produce a thin phosphor-containing sheet having a high accuracy of 100 μm or less.

[Comparative Example 5]
A phosphor-containing sheet was produced by press molding using the ink prepared in Example 1. Specifically, the ink obtained in Example 1 was press-molded to a thickness of 50 μm using a 200 × 200 mm mold. However, a phosphor-containing sheet having a uniform thickness and high accuracy could not be obtained because the coarse particles of the phosphor acted as a support column. In addition, there was a large variation in emission color among phosphor-containing sheets obtained in different lots.

  As in the above results, in the LED lighting devices using the phosphor-containing sheets obtained in Examples 1 to 3 according to the present invention, no transparent region is observed, and there is a variation in the emission color of the LED lighting devices. There were few.

  By using the phosphor-containing sheet obtained by the production method of the present invention, it is possible to suppress the color variation of light emission of the LED lighting device.

DESCRIPTION OF SYMBOLS 1 LED element 2,12 Phosphor containing sheet | seat 2a, 2a (R), 2a (Y) Phosphor 2b Transparent resin 2c Inorganic filler 3, 4 Resin sealing body 5 Light-emitting body accommodating member 5a, 5b Lead 10 Screen mesh 10a Mesh Part 10b Opening 10c Frame 11 Supporting base material 13a Scraper 13b Squeegee 14, 24 Ink 15, 25 Coating film 10, 20, 100, 110 LED lighting device

Claims (7)

A method for producing a phosphor-containing sheet by a screen printing method,
A step of preparing a phosphor-containing ink containing 5 to 90% by mass of phosphor particles having an average particle diameter of 5 to 60 μm, fine particles other than the phosphor particles, and a liquid resin component;
Placing a suitable amount of the phosphor-containing ink on the screen mesh Interview, ink filling to the opening of the screen mesh by spread with a scraper, and printing the transferred while pressing the squeegee to the screen mesh and the supporting substrate be A step of applying the phosphor-containing ink on a support substrate by:
Forming a coating film by leveling the phosphor-containing ink which is coated cloth,
A step of curing the coating film to form a cured film,
The fine particles contain at least one of inorganic particles having an average particle size of 0.005 to 2 μm and resin particles having an average particle size of 0.5 to 20 μm,
The phosphor-containing ink has a viscosity of 200 to 1000 Pa · sec,
It said screen mesh, wire diameter 20 to 70 m, mesh 30～250Myuemu, phosphor-containing sheet manufacturing method characterized by have a mesh and a thickness of 30 to 200 [mu] m. The method for producing a phosphor-containing sheet according to claim 1, wherein a content ratio of the fine particles in the phosphor-containing ink is 0.5 to 50 mass%. The method for producing a phosphor-containing sheet according to claim 1 or 2, wherein the thickness of the coating film is 1 to 5 times the average particle diameter of the phosphor particles. The method for producing a phosphor-containing sheet according to any one of claims 1 to 3, wherein the cured film has a thickness of 10 to 100 µm. The manufacturing method of the fluorescent substance containing sheet of any one of Claims 1-4 which further includes the process of cut | disconnecting the said cured film to the dimension accommodated in a LED lighting apparatus.   The method for producing a phosphor-containing sheet according to claim 5, wherein the dimension is 10 × 10 mm or less.   The method for producing a phosphor-containing sheet according to any one of claims 1 to 6, wherein the liquid resin component is a curable liquid silicone rubber or a silicone resin.

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