JP2010280536A - Method for producing glass member for wavelength conversion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a glass member for wavelength conversion by which the glass member for wavelength conversion excellent in durability can be produced by a simple method while suppressing the deterioration of a phosphor. <P>SOLUTION: The method for producing the glass member for wavelength conversion having the phosphor for converting at least a part of wavelengths of light rays from a light source comprises: a step where a phosphor is fed at least to either forming face of a lower die and an upper die; and a step where a glass material is press-formed by the lower die and the upper die, and the glass material and the phosphor are integrated. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a wavelength conversion glass member, and more particularly to a method for manufacturing a wavelength conversion glass member having a phosphor for converting the wavelength of at least part of light from a light source.

  A white light-emitting diode (hereinafter also referred to as a white LED), which is a type of white light-emitting element, has excellent features such as low power consumption, small size and light weight, little heat generation, mercury-free, and easy adjustment of light quantity. Therefore, it is expected as a next-generation energy-saving illumination light source that can replace incandescent bulbs, fluorescent lamps, and high-pressure discharge lamps.

  As a method of emitting white light using an LED, (1) a method of obtaining white light by combining three or more color LED chips (for example, see Patent Document 1), or (2) a blue LED chip or a near ultraviolet LED chip. And a method of obtaining white light by combining a phosphor (see, for example, Patent Documents 2 and 3). Among these, the method (1) is difficult to balance the emission intensity of each color LED chip, and therefore, a method of obtaining white light by combining the LED chip and the phosphor as shown in (2) is attracting attention. ing.

  Patent Documents 2 and 3 describe a configuration in which a phosphor for converting the wavelength of light from an LED chip is dispersed and fixed in a resin material such as an epoxy resin or a silicone resin. However, such a resin material is prone to deterioration due to light from the LED chip, heat generation of the LED chip and the phosphor, and there is a problem that durability enough to withstand long-term use cannot be obtained. . In particular, when the brightness per unit area is required, such as an LED for a headlight of a car, the deterioration of the resin material in which the phosphor is dispersed is significant and has become a problem.

  Therefore, it is desired to develop a method for fixing a phosphor using glass having higher durability instead of a resin material. However, in the method of kneading the phosphor in the molten glass, the phosphor is left in the high temperature molten glass for a long time, so that the decomposition by the high temperature and the reaction with the components of the molten glass proceed. Will deteriorate significantly. In order to suppress the deterioration of the phosphor for such a problem, a method of dispersing the phosphor in the glass by mixing and sintering a predetermined component of the glass powder and the phosphor powder has been proposed. (See Patent Document 4).

JP 2003-45206 A Japanese Patent Laid-Open No. 10-242513 JP 2002-314142 A JP 2003-258308 A

  However, the method described in Patent Document 4 has a problem that the types of glass that can be used are limited and the process becomes very complicated. In addition, there has been a problem that the phosphor is deteriorated to some extent during sintering.

  The present invention has been made in view of the above technical problems, and an object of the present invention is to produce a wavelength conversion glass member excellent in durability by a simple method while suppressing deterioration of a phosphor. It is providing the manufacturing method of the glass member for wavelength conversion which can do.

  In order to solve the above problems, the present invention has the following features.

1. A method for producing a wavelength-converting glass member having a phosphor for converting the wavelength of at least part of light from a light source,
Supplying a phosphor to at least one molding surface of the lower mold and the upper mold;
A method for producing a glass member for wavelength conversion, comprising: pressing a glass material with the lower mold and the upper mold, and integrating the glass material and the phosphor.

  2. 2. The method for producing a wavelength conversion glass member as described in 1 above, wherein the glass material is a molten glass droplet dropped on the lower mold.

  3. 3. The method for producing a wavelength-converting glass member according to 1 or 2, wherein a phosphor is supplied to the molding surfaces of both the lower mold and the upper mold.

  4). 4. The method for producing a glass member for wavelength conversion according to 3 above, wherein the phosphor comprises a plurality of types of phosphors having different wavelengths of light to be emitted.

  5. A first phosphor that emits light of a first wavelength is supplied to the molding surface of the lower mold, and a second phosphor that emits light of a second wavelength is supplied to the molding surface of the upper mold. 5. The method for producing a wavelength converting glass member as described in 4 above.

  According to the method of the present invention, after supplying the phosphor to at least one of the molding surfaces of the lower mold and the upper mold, the glass material and the phosphor are integrated by pressing the glass material with the lower mold and the upper mold. Therefore, the time during which the phosphor is in contact with the high-temperature glass is short, and deterioration of the phosphor can be sufficiently suppressed. Furthermore, since the area | region where both were mixed is formed in the boundary part of glass and fluorescent substance by press molding, fluorescent substance can be fixed firmly. Therefore, it is possible to produce a wavelength conversion glass member having excellent durability while suppressing deterioration of the phosphor by a simple method.

It is sectional drawing which shows typically white LED provided with the glass member for wavelength conversion. It is a flowchart which shows the manufacturing method of the glass member for wavelength conversion. It is a figure (first half) which shows each process of this embodiment typically. It is a figure (second half) showing typically each process of this embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 4, but the present invention is not limited to the embodiments.

  FIG. 1 is a cross-sectional view schematically showing the white LED 10. The white LED 10 includes an LED chip 12 disposed on a substrate 14 and a wavelength conversion glass member 13 manufactured by the method of this embodiment.

  The LED chip 12 may be a blue LED chip or an ultraviolet or near ultraviolet LED chip. The wavelength converting glass member 13 is disposed so as to surround the LED chip 12, and includes a glass layer 131 and a phosphor layer 132 formed on the surface thereof. Here, the case where the wavelength conversion glass member 13 has a hemispherical shape is illustrated as an example, but is not limited thereto. For example, both sides may have a flat plate shape or a so-called shell shape. The surface of the wavelength converting glass member 13 may be a convex surface, a concave surface or a flat surface. In the case of a convex surface or a concave surface, it may be a spherical surface or a shape having an aspherical component. Since the wavelength conversion glass member 13 is manufactured by pressure-molding a glass material, it can be easily formed into various shapes.

  Since the wavelength converting glass member 13 is manufactured by press molding a glass material with a molding die having a molding surface supplied with a phosphor as will be described later, the boundary between the glass layer 131 and the phosphor layer 132 is produced. There is an area where both are mixed. Therefore, the phosphor layer 132 is firmly fixed to the glass layer 131 and has excellent durability. The phosphor layer 132 may be provided on both surfaces of the glass layer 131, or may be provided on only one of the surfaces. In the case where the phosphor layer 132 is provided on both surfaces of the glass layer 131, the phosphor is supplied to the molding surfaces of both the lower mold and the upper mold to perform pressure molding. Further, when the phosphor layer 132 is provided only on one surface of the glass layer 131, the phosphor is supplied to only one of the molding surfaces of the lower mold and the upper mold and is pressure-molded.

  Next, the manufacturing method of the wavelength conversion glass member 13 will be described with reference to FIGS. FIG. 2 is a flowchart showing an example of a method of manufacturing the wavelength conversion glass member 13, and FIGS. 3 and 4 are diagrams schematically showing each step of the present embodiment.

  In addition, although the case where a molten glass droplet is used as an example is described here as an example, the glass material for pressure molding is not limited to a molten glass droplet, a molten glass having a predetermined volume is used. A solidified product can also be used. Moreover, it is also preferable to use what solidified glass processed into desired shapes, such as a bulb | ball and a flat plate. When solidified glass is used as the glass material, it may be used by heating it to a temperature at which pressure molding is possible together with the lower mold 21 and the upper mold 22. On the other hand, when a molten glass droplet is used as the glass material, a glass molded body is obtained by receiving the molten glass droplet with the lower mold 21 at a relatively low temperature, and cooling and solidifying it while pressing with the upper mold 22 as it is. There is an advantage that it can be manufactured efficiently in a very short time.

  Hereinafter, as an example of the manufacturing method of the glass member for wavelength conversion of this embodiment, the case where a molten glass droplet is used as a glass material is mentioned as an example, and it demonstrates later for each process according to the flowchart shown in FIG.

  First, each of the lower mold 21 and the upper mold 22 is heated to a predetermined temperature (step S110) (see FIG. 3A). The lower mold 21 and the upper mold 22 are configured to be heated to a predetermined temperature by a heating unit (not shown). As the heating means, known heating means can be appropriately selected and used. For example, a cartridge heater that is used by being embedded inside the member to be heated, a sheet heater that is used while being in contact with the outside of the member to be heated, an infrared heating device, a high-frequency induction heating device, or the like can be used.

  The predetermined temperature may be appropriately selected according to the type of glass or phosphor. In general, if the temperature of the lower mold 21 or the upper mold 22 is too low, the adhesion between the glass layer 131 and the phosphor layer 132 tends to be reduced, and it becomes difficult to obtain high shape accuracy. On the other hand, if the temperature is set higher than necessary, the phosphor is likely to deteriorate, and the lifetimes of the lower mold 21 and the upper mold 22 are likely to be shortened. From these viewpoints, it is usually preferable to set the temperature to about Tg-100 ° C. to Tg + 100 ° C., where Tg is the glass transition temperature of the glass used. The heating temperatures of the lower mold 21 and the upper mold 22 may be the same or different.

  The heating temperature of the lower mold 21 and the upper mold 22 may be changed for each process, but the control temperature should be kept constant until the glass molded body (wavelength conversion glass member) is recovered in the process S170. Thus, high production efficiency can be ensured. In addition, a plurality of glass molded bodies can be repeatedly produced while keeping the control temperature of the lower mold 21 and the upper mold 22 constant. Therefore, it is not necessary to repeat the heating and cooling of the lower mold 21 and the upper mold 22 every time one glass molded body is manufactured, and an optical element can be manufactured efficiently in an extremely short time. Here, keeping the control temperature of the lower die 21 and the upper die 22 constant means that the target set temperature in the temperature control for heating the lower die 21 and the upper die 22 is kept constant. This does not mean that temperature fluctuation due to contact with the molten glass droplet 31 or the like must be prevented during implementation.

  The molding surface 211 of the lower mold 21 and the molding surface 221 of the upper mold 22 are precisely machined into a predetermined shape corresponding to the shape of the wavelength conversion glass member manufactured in advance. Thereby, the glass member for wavelength conversion which has high shape accuracy can be manufactured easily. Moreover, since the surface of the wavelength conversion glass member is formed by the molten glass droplet 31 coming into contact with the molding surfaces 211 and 221 and rapidly cooled, a surface smoother than the molding surfaces 211 and 221 can be obtained. . From the viewpoint of obtaining a sufficiently smooth surface, the arithmetic mean roughness Ra of the molding surfaces 211 and 221 is preferably 0.2 μm or less. The arithmetic average roughness Ra is a roughness parameter defined in JIS B 0601: 2001.

  The materials of the lower mold 21 and the upper mold 22 are heat-resistant alloys (stainless steel, etc.), super hard materials mainly composed of tungsten carbide, various ceramics (silicon carbide, silicon nitride, aluminum nitride, etc.), composite materials containing carbon, etc. It can be suitably selected from known materials as a mold for producing a glass molded body. The lower mold 21 and the upper mold 22 may be made of the same material or different materials.

  It is also preferable to provide a coating layer on the surfaces of the lower mold 21 and the upper mold 22 in order to improve the releasability from the phosphor. For example, various metals (chromium, aluminum, titanium, platinum, etc.), nitrides (chromium nitride, aluminum nitride, titanium nitride, boron nitride, etc.), oxides (chromium oxide, aluminum oxide, titanium oxide, etc.), etc. are used. Can do. There is no limitation on the method for forming the coating layer, and it may be appropriately selected from known film forming methods. For example, vacuum deposition, sputtering, CVD, etc. are mentioned.

  Next, the lower mold | type 21 is moved to a dripping position (process S120), and fluorescent substance is supplied to the molding surfaces 211 and 221 (process S130) (refer FIG.3 (b)).

  The lower mold 21 has a position (dropping position) for receiving the molten glass droplet 31 below the dropping nozzle 23 by a driving means (not shown), and a position for pressure-molding the molten glass droplet 31 facing the upper mold 22. It is configured to be movable between (pressing position). The movement to the dropping position may be before or after heating the lower mold 21 and the upper mold 22 as long as the molten glass droplet 31 is not dropped in the next step S140.

  The phosphor may be appropriately selected and used according to the use and type of the white LED. When a blue LED chip is used as the LED chip 12, for example, a blue LED + yellow phosphor is configured using a phosphor that converts the wavelength of blue light into yellow light (excited with blue light and emits yellow light). Thus, white light can be obtained. By using two or more kinds of phosphors, for example, a configuration of blue LED + yellow phosphor + red phosphor or a configuration of blue LED + green phosphor + red phosphor can be used. Further, when an ultraviolet or near-ultraviolet LED chip is used as the LED chip 12, white light is obtained by adopting a configuration of blue phosphor + yellow phosphor or a configuration of blue phosphor + green phosphor + red phosphor. Can do.

  Suitable phosphors include YAG phosphors, silicate phosphors, nitride phosphors, oxynitride phosphors, sulfide phosphors, thiogallate phosphors, aluminate phosphors, and the like.

  There is no particular limitation on the method of supplying the phosphor. The phosphor may be supplied in a powder state. However, from the viewpoint of preventing scattering and stabilizing the supply amount, it is preferable to supply the phosphor in a state of being dispersed in a liquid or gel binder. At this time, when the boiling point of the binder used is lower than the temperature of the molding surfaces 211 and 221 for supplying the phosphor, there is an advantage that the phosphor can be supplied without leaving an unnecessary binder on the molding surfaces 211 and 221. For example, organic solvents such as ethanol and acetone are suitable.

  When the phosphor layer 132 is provided on only one surface of the glass layer 131, the phosphor is supplied only to one of the molding surfaces 211 and 221 of the lower mold 21 and the upper mold 22. When the phosphor layer 132 is provided on both surfaces of the glass layer 131, the phosphor is supplied to the molding surfaces 211 and 221 of both the lower mold 21 and the upper mold 22.

  When only one type of phosphor is supplied, the phosphor may be supplied to only one of the molding surfaces 211 and 221, but the same phosphor is supplied to both molding surfaces 211 and 221 to obtain a phosphor layer By providing 132 on both surfaces of the glass layer 131, the thickness of each phosphor layer 132 can be reduced, so that there is an advantage that the phosphor can be fixed more firmly and durability is improved. When a plurality of phosphors are used, a plurality of phosphors may be distributed and supplied to the binder, or after the binder in which the first phosphor is dispersed is supplied, the second phosphor is further provided thereon. A binder in which a phosphor is dispersed may be supplied.

  In addition, it is also preferable that the phosphors supplied to the molding surface 211 of the lower mold 21 and the phosphors supplied to the molding surface 221 of the upper mold 22 are different types and the wavelengths of emitted light are different. In general, when a plurality of types of phosphors are used at the same time, loss due to so-called multistage excitation, in which light emitted from the first phosphor excites another second phosphor, tends to be a problem. However, a first phosphor that emits light of the first wavelength is supplied to the molding surface of the lower mold, and a second phosphor that emits light of the second wavelength is supplied to the molding surface of the upper mold. And the loss by such multistage excitation can be reduced by setting it as the structure which provides each fluorescent substance layer 132 on both surfaces of the glass layer 131, respectively. From the viewpoint of more effectively reducing the loss due to multi-stage excitation, the phosphor layer having the longer emission wavelength on the surface where the light from the LED chip serving as the light source reaches first (the surface on which light enters) 132 is formed, and a phosphor is formed on each of the molding surfaces 211 and 221 so that a phosphor layer 132 having a shorter emission wavelength is formed on the surface that reaches later (the surface that emits light). It is more preferable to supply.

  Next, the molten glass droplet 31 is dropped on the lower mold 21 (step S140) (see FIGS. 3C and 4A). The dripping of the molten glass droplet 31 is performed by heating a pipe-shaped dripping nozzle 23 connected to a melting tank (not shown) containing molten glass to a predetermined temperature. When the dripping nozzle 23 is heated to a predetermined temperature by the heater 24, the molten glass is supplied to the tip of the dripping nozzle 23 by its own weight, and accumulates in droplets by the surface tension. When the molten glass collected at the tip of the dropping nozzle 23 reaches a certain mass, it is naturally separated from the dropping nozzle 23 by gravity and falls downward as a molten glass droplet 31.

  The mass of the molten glass droplet 31 dropped from the dropping nozzle 23 can be adjusted by the outer diameter of the tip of the dropping nozzle 23 and the like, and depending on the type of glass, the molten glass droplet 31 of about 0.1 g to 2 g is dropped. Can be made. In addition to the method of separating from the dropping nozzle 23 by gravity, a method of pressing and extruding molten glass or a method of separating by applying an external force such as airflow or vibration may be used. Further, the molten glass droplet 31 dropped from the dropping nozzle 23 is once made to collide with a member provided with through-holes, and a part of the collided molten glass droplet 31 is passed through the through-holes to be miniaturized. The molten glass droplets may be dropped on the lower mold 21. By using such a method, it is possible to obtain a minute molten glass droplet of, for example, 0.01 g, so that a smaller amount of glass is obtained than when the molten glass droplet 31 dropped from the dropping nozzle 23 is directly received by the lower mold 21. The molded body can be manufactured.

  There is no restriction | limiting in particular in the kind of glass which can be used, A well-known glass can be selected and used according to a use. Examples thereof include optical glasses such as borosilicate glass, silicate glass, phosphate glass, and lanthanum glass.

  Next, the lower mold 21 is moved to the pressure position (step S150), and the upper mold 22 is moved downward to form the molten glass droplet 31 by pressure (step S160) (see FIG. 4B). The molten glass droplet 31 received by the lower mold 21 is rapidly cooled by coming into contact with the lower mold 21 and the upper mold 22 and solidified to become a glass molded body 32. At this time, the phosphor supplied to the molding surfaces 211 and 221 is fixed to the surface of the glass molding 32. The time from the start of pressurization to the solidification of the glass depends on the type and size of the glass, but is usually in the range of several seconds to several tens of seconds. As described above, according to the method of the present embodiment, the time during which the phosphor is in contact with the high-temperature molten glass can be extremely shortened, so that deterioration of the phosphor can be sufficiently suppressed. Moreover, since the area | region where both were mixed is formed in the boundary part of glass and fluorescent substance by pressure molding, fluorescent substance can be fixed firmly.

  The load applied to press the molten glass droplet 31 may be constant or may be changed with time. What is necessary is just to set the magnitude | size of a load suitably according to the size etc. of the glass forming body 32 to manufacture. Usually, it may be set in the range of several hundred to several thousand N. The driving means for moving the upper mold 22 up and down is not particularly limited, and known driving means such as an air cylinder, a hydraulic cylinder, and a servo motor can be appropriately selected and used.

  In FIG. 4B, only the upper mold 22 is moved in the pressurizing direction to perform the pressure molding of the molten glass droplet 31. However, the upper mold 22 is not limited to such a configuration. May be fixed, and only the lower mold 21 may be moved in the pressing direction to perform pressure molding, or both the lower mold 21 and the upper mold 22 may be moved to perform pressure molding.

  Next, the upper mold 22 is moved upward to release the pressure, and the solidified glass molded body 32 is recovered (step S170) (see FIG. 4C). The glass molded body 32 may be collected using, for example, a mold release device 25 using vacuum suction. After recovering the glass molded body 32, when the glass molded body 32 is subsequently manufactured, the lower mold 21 is moved again to the dropping position (step S120), and the subsequent steps may be repeated.

  In addition, the manufacturing method of the glass member for wavelength conversion of this embodiment may include another process other than having demonstrated here. For example, it is also preferable to provide a step of inspecting the shape of the glass molded body 32 before collecting the glass molded body 32 and a step of cleaning the lower mold 21 and the upper mold 22 after collecting the glass molded body 32.

  The glass molded body 32 manufactured by the manufacturing method of this embodiment can be used as it is as a glass member for wavelength conversion for white LEDs. Further, the glass molded body 32 can be used as a glass member for wavelength conversion after being subjected to post-treatment such as outer diameter processing and annealing treatment.

10 White LED
12 LED chip 13 Glass member for wavelength conversion 131 Glass layer 132 Phosphor layer 14 Substrate 21 Lower mold 211 Molding surface 22 Upper mold 221 Molding surface 23 Dripping nozzle 31 Molten glass droplet

Claims (5)

A method for producing a wavelength-converting glass member having a phosphor for converting the wavelength of at least part of light from a light source,
Supplying a phosphor to at least one molding surface of the lower mold and the upper mold;
A method for producing a glass member for wavelength conversion, comprising: pressing a glass material with the lower mold and the upper mold, and integrating the glass material and the phosphor.   The said glass raw material is the molten glass droplet dripped at the said lower mold | type, The manufacturing method of the glass member for wavelength conversion of Claim 1 characterized by the above-mentioned.   3. The method for producing a wavelength conversion glass member according to claim 1, wherein the phosphor is supplied to molding surfaces of both the lower mold and the upper mold. 4.   The said fluorescent substance consists of multiple types of fluorescent substance from which the wavelength of the light to light-emit differs, The manufacturing method of the glass member for wavelength conversion of Claim 3 characterized by the above-mentioned.   A first phosphor that emits light of a first wavelength is supplied to the molding surface of the lower mold, and a second phosphor that emits light of a second wavelength is supplied to the molding surface of the upper mold. The manufacturing method of the glass member for wavelength conversion of Claim 4 characterized by the above-mentioned.

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