JP2019015848A - Wavelength conversion member and method for manufacturing the same - Google Patents

Abstract

To provide a wavelength conversion member including a wavelength conversion layer where a phosphor is sealed to glass and having excellent optical characteristics and light extraction efficiency without depending on phosphor concentrations in the wavelength conversion layer, and a method for manufacturing the same.SOLUTION: A wavelength conversion member 1 is provided that includes: a first wavelength conversion layer 10 having a tabular glass 10a and a phosphor 10b contained in the glass 10a; a glass layer 11 formed on one surface of the first wavelength conversion layer 10; and a reflective layer 12 formed on a surface opposite to the first wavelength conversion layer 10 of the glass layer 11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wavelength conversion member and a manufacturing method thereof.

  Conventionally, it is a phosphor composite member in which an inorganic powder sintered body layer containing glass powder and inorganic phosphor powder is formed on the surface of a ceramic substrate, and when the excitation light is irradiated, the ceramic substrate and A phosphor composite member in which an inorganic powder sintered body layer emits fluorescence having different wavelengths is known (see, for example, Patent Document 1).

  The phosphor composite member described in Patent Document 1 is a transmission-type wavelength conversion member, and yellow fluorescence emitted from a ceramic substrate and red and / or green fluorescence emitted from an inorganic powder sintered body layer, White light is obtained by synthesizing with blue excitation light transmitted through the phosphor composite member.

JP 2012-52061 A

  The phosphor composite member described in Patent Document 1 is a transmission-type wavelength conversion member. However, a reflection-type wavelength conversion member usually includes a reflection layer for reflecting light, and the phosphor is contained in glass. In order to efficiently scatter light by the wavelength conversion layer in which is sealed, it is required to increase the concentration of the phosphor in the wavelength conversion layer.

  However, the present inventors have found that voids are generated in the wavelength conversion layer when the concentration of the red phosphor in the wavelength conversion layer in which the phosphor is sealed in glass is increased. In addition, before the reflective layer is formed, it is necessary to polish the surface of the underlying layer to be mirror-finished, but when trying to directly form the reflective layer on the wavelength conversion layer in which the void is generated, An abrasive enters the gap in the wavelength conversion layer and adversely affects the optical properties of the wavelength conversion layer. If there are too many gaps, it cannot be mirror-finished even when polished, forming a high-quality reflective layer. I found it impossible.

  An object of the present invention is to provide a wavelength conversion member having a wavelength conversion layer in which a phosphor is sealed in glass, and having excellent optical characteristics and light extraction efficiency, regardless of the concentration of the phosphor in the wavelength conversion layer, and its It is to provide a manufacturing method.

  In order to achieve the above object, an aspect of the present invention provides the following wavelength conversion members [1] to [7] and methods for producing the wavelength conversion members [8] and [9].

[1] A first wavelength conversion layer having a flat glass and a phosphor contained in the glass, a glass layer formed on one surface of the first wavelength conversion layer, and the glass layer A wavelength conversion member comprising: a reflection layer formed on a surface opposite to the first wavelength conversion layer.

[2] The wavelength conversion member according to [1], wherein the phosphor is a red phosphor.

[3] The wavelength conversion member according to [1] or [2], in which a cross-sectional area ratio of the red phosphor in an arbitrary cross section of the first wavelength conversion layer is 54% or more.

[4] The wavelength conversion member according to any one of [1] to [3], wherein the glass layer has a thickness of 5 μm or more.

[5] Any of [1] to [4] above, comprising a second wavelength conversion layer containing a yellow phosphor formed on the surface of the first wavelength conversion layer opposite to the glass layer. The wavelength conversion member of Claim 1.

[6] In the above [5], the second wavelength conversion layer is made of a single crystal of a YAG phosphor, and the total thickness of the first wavelength conversion layer and the thickness of the glass layer is 300 μm or less. The wavelength conversion member as described.

[7] The wavelength conversion member according to [5] or [6] above, wherein an interface between the second wavelength conversion layer and the first wavelength conversion layer has an uneven shape.

[8] A step of forming a first wavelength conversion layer made of glass containing a red phosphor, a step of forming a glass layer on one surface of the first wavelength conversion layer, and a surface of the glass layer The manufacturing method of the wavelength conversion member including the process of performing a grinding | polishing process, and the process of forming a reflection layer on the surface of the said glass layer in which the said grinding | polishing process was performed.

[9] The method for manufacturing a wavelength conversion member according to [8], wherein a cross-sectional area ratio of the red phosphor in an arbitrary cross section of the first wavelength conversion layer is 54% or more.

  According to the present invention, a wavelength conversion layer having a wavelength conversion layer in which a phosphor is sealed in glass, having excellent optical characteristics and light extraction efficiency regardless of the concentration of the phosphor in the wavelength conversion layer, and the A manufacturing method can be provided.

FIG. 1 is a vertical sectional view of a wavelength conversion member according to an embodiment. 2A to 2D are vertical cross-sectional views illustrating the manufacturing steps of the wavelength conversion member according to the embodiment. FIG. 3A is an SEM (Scanning Electron Microscope) observation image of the cross section of the first wavelength conversion layer when the cross-sectional area ratio of the red phosphor in the first wavelength conversion layer is 46%. (B) is a SEM observation image of the cross section of the first wavelength conversion layer when the cross-sectional area ratio of the red phosphor in the first wavelength conversion layer is 54%. FIG. 4 is an image observed by an optical microscope of the surface of the first wavelength conversion layer including the polished void. FIG. 5 is an SEM observation image of a cross section in the thickness direction of the laminated first wavelength conversion layer, glass layer, and second wavelength conversion layer.

(Configuration of wavelength conversion member)
FIG. 1 is a vertical sectional view of a wavelength conversion member 1 according to an embodiment. The wavelength conversion member 1 includes a flat glass 10a and a first wavelength conversion layer 10 having a red phosphor 10b included in the glass 10a, and a glass layer formed on one surface of the first wavelength conversion layer 10. 11, the reflection layer 12 formed on the surface of the glass layer 11 opposite to the first wavelength conversion layer 10, and the surface of the first wavelength conversion layer 10 opposite to the glass layer 11. And a second wavelength conversion layer 13 containing a yellow phosphor, and a heat dissipation member 14 bonded by a bonding layer 15 on the surface of the reflective layer 12 opposite to the glass layer 11.

  The wavelength conversion member 1 is a reflective wavelength conversion member that allows excitation light to enter from the second wavelength conversion layer 13 side and extracts mixed light of excitation light and fluorescence from the incident side of the excitation light. The reason why the second wavelength conversion layer 13 is on the light extraction side among the first wavelength conversion layer 10 and the second wavelength conversion layer 13 is to improve heat dissipation. The heat emitted from the phosphor is mainly dissipated from the surface opposite to the light extraction surface (reflective film surface), so the red phosphor that generates heat more easily than the yellow phosphor is on the heat dissipating side (reflective film side). By providing, it becomes easy to radiate the heat | fever which generate | occur | produced with red fluorescent substance, and the emitted-heat amount in the whole fluorescent substance is suppressed.

  In the reflective wavelength conversion member 1, it is required to increase the concentration of the red phosphor 10 b in the first wavelength conversion layer 10 in order to efficiently scatter light in the first wavelength conversion layer 10. However, when the concentration of the red phosphor 10b in the first wavelength conversion layer 10 is increased, voids are generated in the first wavelength conversion layer 10.

  On the other hand, before the reflective layer 12 is formed, the surface of the underlying layer needs to be polished to be mirror-finished. However, the reflective layer 12 is formed on the first wavelength conversion layer 10 in which the gap is generated. If it is directly formed, the abrasive enters the voids of the first wavelength conversion layer 10 and adversely affects the optical characteristics of the first wavelength conversion layer 10. In addition, when there are many voids, even if polishing is performed, the mirror surface cannot be mirrored, and a problem that the high-quality reflective layer 12 cannot be formed may occur.

  Therefore, in the manufacture of the wavelength conversion member 1 according to the embodiment, a glass layer 11 that does not contain a phosphor is formed on the first wavelength conversion layer 10, and the glass layer 11 is polished to be mirror-finished. A reflective layer 12 is formed thereon.

  For this reason, even if the first wavelength conversion layer 10 includes a gap, the first wavelength conversion does not interfere with the entry of the abrasive into the gap or the mirroring of the base of the reflective layer 12. The layer 10 can prevent the deterioration of the optical characteristics of the first wavelength conversion layer 10 and the deterioration of the quality of the reflection layer 12 due to the gap.

  Therefore, when the density | concentration of the red fluorescent substance 10b in the 1st wavelength conversion layer 10 is so high that a space | gap is generated, it can be said that the structure of the wavelength conversion member 1 is especially effective.

  For example, the first wavelength conversion layer 10 includes the red phosphor 10b in the glass 10a, and the cross-sectional area ratio of the red phosphor 10b in an arbitrary cross section of the first wavelength conversion layer 10 (the first wavelength conversion in a certain cross section). When the ratio of the area of the red phosphor 10b to the entire area of the layer 10) is 54% or more, voids are likely to occur.

  Here, when the concentration of the red phosphor 10b in the first wavelength conversion layer 10 is approximately 50% by mass or more, the cross-sectional area ratio of the red phosphor 10b in an arbitrary cross section of the first wavelength conversion layer 10 is 54. % Or more.

  Further, when the first wavelength conversion layer 10 contains an inorganic material other than the red phosphor 10b, for example, another phosphor or a scattering material, in the glass 10a, the red color in an arbitrary cross section of the first wavelength conversion layer 10 Even if the cross-sectional area ratio of the phosphor 10b is less than 54% (the concentration of the red phosphor 10b in the first wavelength conversion layer 10 is less than 50% by mass), voids may occur.

The glass 10a of the first wavelength conversion layer 10 is made of low-melting glass, and in particular, it is preferably made of low-melting glass having a melting point of 500 ° C. or lower such as Bi ₂ O ₃ —ZnO—B ₂ O ₃ . By using the low melting point glass as the material of the glass 10a, it is possible to suppress deterioration of the red phosphor 10b due to heat for melting the glass 10a when the first wavelength conversion layer 10 is formed.

The red phosphor 10b of the first wavelength conversion layer 10 is a phosphor that emits fluorescence having a central wavelength at a wavelength of 590 to 780 nm. For example, (Sr, Ca) AlSi (N, O) ₃ : Eu is red fluorescent. It can be used as the body 10b.

  Similarly to the glass 10a of the first wavelength conversion layer 10, the glass layer 11 is made of low-melting glass in order to suppress deterioration due to heat of the red phosphor 10b of the first wavelength conversion layer 10. Further, as the low melting point glass constituting the glass layer 11, the same glass as the low melting point glass constituting the glass 10a of the first wavelength conversion layer 10 may be used.

  Considering that the first wavelength conversion layer 10 under the glass layer 11 is exposed and adversely affects the optical characteristics of the wavelength conversion member 1, the design value is such that the thickness after polishing is 5 μm or more. It is preferable to form the glass layer 11. That is, it is preferable that the thickness of the glass layer 11 in the completed wavelength conversion member 1 is 5 μm or more.

  Although the glass layer 11 is formed by screen printing or the like, there is often a thickness variation of about 10 μm after the formation. For this reason, it is preferable that the thickness of the glass layer 11 before polishing is 15 μm or more in order to polish with a polishing thickness sufficient for mirror finishing and to make the thickness after polishing 5 μm or more. In addition, since the polishing thickness of the polishing process by CMP (Chemical Mechanical Polishing) after the formation of the glass layer 11 may vary by about 10 μm at maximum, the first wavelength conversion layer 10 under the glass layer 11 is exposed. In order to prevent this more reliably, the thickness of the glass layer 11 before polishing is more preferably 25 μm or more, and further preferably 30 μm or more.

  The reflection layer 12 is made of, for example, a metal such as Al, Ag, or an Ag alloy, or a multilayer dielectric made of silicon dioxide and titanium oxide.

  The second wavelength conversion layer 13 is a phosphor that emits fluorescence having a center wavelength different from that of the red phosphor 10b of the first wavelength conversion layer 10, for example, a yellow phosphor that emits fluorescence having a center wavelength at a wavelength of 535 to 590 nm. Is a flat phosphor-containing member. Further, the second wavelength conversion layer 13 includes, for example, a single crystal of a phosphor that emits fluorescence having a central wavelength different from that of the red phosphor 10b, or a phosphor that emits fluorescence having a central wavelength different from that of the red phosphor 10b. Made of ceramics.

As the yellow phosphor contained in the second wavelength conversion layer 13, (Lu, Gd, Y) ₃ Al ₅ O ₁₂ : Ce (YAG phosphor) can be used.

  When the second wavelength conversion layer 13 includes a yellow phosphor, for example, by irradiating the wavelength conversion member 1 with blue light having a center wavelength at a wavelength of 430 to 470 nm as excitation light, the first wavelength conversion layer 10 and White light can be extracted as a mixed light of the fluorescence emitted from the second wavelength conversion layer 13 and the excitation light reflected without being absorbed by the wavelength conversion member 1.

  In the wavelength conversion member 1, the concentration of the red phosphor 10 b of the first wavelength conversion layer 10 can be increased, and the second wavelength conversion layer 13 can be formed from a single crystal or ceramics. Therefore, the wavelength conversion member 1 has excellent heat dissipation characteristics. For this reason, a light output light source such as a laser light source can be used as a light source for irradiating the wavelength conversion member 1 with excitation light.

  When the first wavelength conversion layer 10 and the second wavelength conversion layer 13 are thick, peeling between the first wavelength conversion layer 10 and the second wavelength conversion layer 13 is likely to occur due to a difference in thermal expansion coefficient. For this reason, for example, when the second wavelength conversion layer 13 is made of a single crystal of a YAG phosphor, the total thickness of the first wavelength conversion layer and the glass layer is preferably 100 μm or less. In addition, when the surface of the second wavelength conversion layer 13 and the first wavelength conversion layer 10 is subjected to a roughening treatment to improve adhesion, the total thickness of the first wavelength conversion layer and the glass layer is increased. May be 300 μm or less.

  In order to improve the adhesion between the second wavelength conversion layer 13 and the first wavelength conversion layer 10 to prevent peeling, the interface between the second wavelength conversion layer 13 and the first wavelength conversion layer 10 has an uneven shape. Preferably there is.

  Further, in order to make it difficult for the second wavelength conversion layer 13 and the first wavelength conversion layer 10 to peel off, the difference in linear expansion coefficient between the glass 10a of the first wavelength conversion layer 10 and the second wavelength conversion layer 13 is first. It is preferable that it is 1 ppm or less on the basis of the wavelength conversion layer 10 of this.

  The refractive index difference between the glass 10a of the first wavelength conversion layer 10 and the second wavelength conversion layer 13 is preferably ± 0.2 or less. When the excitation light is laser light and the second wavelength conversion layer 13 is made of a highly transparent material such as a single crystal, the refractive index difference between the first wavelength conversion layer 10 and the second wavelength conversion layer 13 is large. This is because the laser light may be regularly reflected at the interface between the first wavelength conversion layer 10 and the second wavelength conversion layer 13 and the laser light may not be scattered.

The heat radiating member 14 is made of, for example, a metal such as Cu, CuW, or Al, or a ceramic such as AlN, SiC, or Al ₂ O ₃ . The bonding layer 15 is made of AuSn solder, SuAgCu solder, silver paste, or the like.

(Manufacturing method of wavelength conversion member)
Below, an example of the manufacturing process of the wavelength conversion member 1 which concerns on embodiment is demonstrated.

  2A to 2D are vertical cross-sectional views illustrating manufacturing steps of the wavelength conversion member 1 according to the embodiment.

  First, as shown in FIG. 2A, the first wavelength conversion layer 10 is formed on the second wavelength conversion layer 13.

  First, a red phosphor 10b that is a raw material of the first wavelength conversion layer 10, a mixed solution containing glass 10a, and a second wavelength conversion layer 13 are prepared.

  The mixed liquid that is a raw material of the first wavelength conversion layer 10 is obtained by mixing a low melting point frit glass as the glass 10a, a red phosphor 10b, and a diluent vehicle on a glass container, and then under a pressure of 0.1 kPa. For 2 minutes by vacuum degassing.

  The second wavelength conversion layer 13 is obtained by subjecting the surface of a flat plate-like YAG-based single crystal as a flat plate-like phosphor-containing member to organic cleaning, and further performing a heat treatment at 1000 ° C. to burn off the dirt on the surface. can get.

  And the liquid mixture which is the raw material of the 1st wavelength conversion layer 10 is apply | coated on the 2nd wavelength conversion layer 13 by screen printing. Thereafter, the applied mixed solution is subjected to vacuum deaeration for 2 minutes under a pressure of 0.1 kPa. Finally, baking is performed for 20 minutes at a temperature of 480 ° C. in an air atmosphere to obtain the first wavelength conversion layer 10.

  In the case where the interface between the second wavelength conversion layer 13 and the first wavelength conversion layer 10 has an uneven shape, the first wavelength conversion layer 10 is provided on the surface of the second wavelength conversion layer 13 subjected to the uneven processing. What is necessary is just to form.

  Next, as shown in FIG. 2B, the glass layer 11 is formed on the surface of the first wavelength conversion layer 10 opposite to the second wavelength conversion layer 13.

  First, a mixed liquid that is a raw material of the glass layer 11 is prepared. This mixed solution can be obtained by mixing a low melting point frit glass and a diluent vehicle in a glass container, followed by vacuum degassing for 2 minutes under a pressure of 0.1 kPa.

  And the liquid mixture which is the raw material of the glass layer 11 is apply | coated on the 1st wavelength conversion layer 10 by screen printing. Thereafter, the applied mixed solution is subjected to vacuum deaeration for 2 minutes under a pressure of 0.1 kPa. Finally, baking is performed in an air atmosphere at a temperature of 480 ° C. for 20 minutes to obtain the glass layer 11.

  Here, as described above, the glass layer 11 is preferably formed to a thickness of 15 μm or more, more preferably a thickness of 25 μm or more, and a thickness of 30 μm or more. Is more preferable.

  Next, as shown in FIG. 2C, the surface of the glass layer 11 opposite to the first wavelength conversion layer 10 is subjected to a polishing process by CMP to be mirror-finished. At this time, the polishing thickness is set to be less than the thickness of the glass layer 11 so that the first wavelength conversion layer 10 is not exposed.

  Further, as described above, since the glass layer 11 often has a thickness variation of about 10 μm, it is preferable to perform polishing with a polishing thickness of 10 μm or more in order to more surely make a mirror surface.

  Next, as shown in FIG. 2D, the reflective layer 12 is formed on the surface of the mirror-finished glass layer 11 opposite to the first wavelength conversion layer 10 by vapor deposition or sputtering.

  Then, the heat radiating member 14 is joined using the joining layer 15 on the surface on the opposite side to the glass layer 11 of the reflection layer 12, and the wavelength conversion member 1 is obtained.

(Effect of embodiment)
According to the embodiment, the wavelength conversion member having a wavelength conversion layer in which a phosphor is sealed in glass and having excellent optical characteristics and light extraction efficiency regardless of the concentration of the phosphor in the wavelength conversion layer, And a manufacturing method thereof.

  FIG. 3A is an SEM (Scanning Electron Microscope) observation image of the cross section of the first wavelength conversion layer 10 in which the cross-sectional area ratio of the red phosphor 10b is 46%, and FIG. It is a SEM observation image of the cross section of the 1st wavelength conversion layer 10 whose cross-sectional area ratio of the body 10b is 54%.

In the first wavelength conversion layer 10 shown in FIGS. 3A and 3B, only the red phosphor 10b is included in the glass 10a, and other inorganic materials are not included. Further, Bi ₂ O ₃ —ZnO—B ₂ O ₃ and (Sr, Ca) AlSi (N, O) ₃ : Eu are used as the glass 10a and the red phosphor 10b, respectively.

  According to FIGS. 3A and 3B, the cross section of the first wavelength conversion layer 10 in which the cross-sectional area ratio of the red phosphor 10b is 46% hardly includes voids, and the cross-sectional area of the red phosphor 10b. A lot of voids 20 are included in the cross section of the first wavelength conversion layer 10 whose ratio is 54%.

  In addition, the density | concentration of the red fluorescent substance 10b in the 1st wavelength conversion layer 10 shown by Fig.3 (a) is about 25 mass%, and the red fluorescence in the 1st wavelength conversion layer 10 shown by FIG.3 (b). The concentration of the body 10b is approximately 50% by mass.

  FIG. 4 is an image observed by an optical microscope of the surface of the first wavelength conversion layer 10 including the polished voids. A set of black dots observed in the observation image of FIG. 4 is an abrasive that has entered the voids of the first wavelength conversion layer 10.

  FIG. 4 shows that when the first wavelength conversion layer 10 including the gap is polished, the abrasive enters the gap. The abrasive that has entered the first wavelength conversion layer 10 degrades the optical characteristics of the first wavelength conversion layer 10.

  FIG. 5 is an SEM observation image of a cross section in the thickness direction of the laminated first wavelength conversion layer 10, the glass layer 11 before polishing, and the second wavelength conversion layer 13.

In the first wavelength conversion layer 10 shown in FIG. 5, only the red phosphor 10b is included in the glass 10a, and other inorganic materials are not included. Further, Bi ₂ O ₃ —ZnO—B ₂ O ₃ and (Sr, Ca) AlSi (N, O) ₃ : Eu are used as the glass 10a and the red phosphor 10b, respectively. Further, Bi ₂ O ₃ —ZnO—B ₂ O ₃ is used as the glass layer 11, and a YAG-based phosphor is used as the second wavelength conversion layer 13.

  The first wavelength conversion layer 10, the glass layer 11, and the second wavelength conversion layer 13 shown in FIG. 5 are formed by the method shown in the above embodiment.

  Although the embodiments and examples of the present invention have been described above, the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the spirit of the invention.

  The embodiments and examples described above do not limit the invention according to the claims. It should be noted that not all combinations of features described in the embodiments and examples are necessarily essential to the means for solving the problems of the invention.

DESCRIPTION OF SYMBOLS 1 ... Wavelength conversion member, 10 ... 1st wavelength conversion layer, 10a ... Glass, 10b ... Red fluorescent substance 10b, 11 ... Glass layer, 12 ... Reflection layer, 13 ... 2nd wavelength conversion layer, 14 ... Heat dissipation member, 20 ... void

Claims (9)

A first wavelength conversion layer having a flat glass and a phosphor contained in the glass;
A glass layer formed on one surface of the first wavelength conversion layer;
A reflective layer formed on a surface of the glass layer opposite to the first wavelength conversion layer;
A wavelength conversion member comprising: The phosphor is a red phosphor,
The wavelength conversion member according to claim 1. The cross-sectional area ratio of the red phosphor in an arbitrary cross section of the first wavelength conversion layer is 54% or more;
The wavelength conversion member according to claim 1 or 2. The glass layer has a thickness of 5 μm or more.
The wavelength conversion member of any one of Claims 1-3. A second wavelength conversion layer including a yellow phosphor formed on a surface of the first wavelength conversion layer opposite to the glass layer;
The wavelength conversion member of any one of Claims 1-4. The second wavelength conversion layer is made of a single crystal of a YAG phosphor,
The sum of the thickness of the first wavelength conversion layer and the thickness of the glass layer is 300 μm or less,
The wavelength conversion member according to claim 5. The interface between the second wavelength conversion layer and the first wavelength conversion layer is uneven.
The wavelength conversion member according to claim 5 or 6. Forming a first wavelength conversion layer made of glass containing a red phosphor;
Forming a glass layer on one surface of the first wavelength conversion layer;
A step of polishing the surface of the glass layer;
Forming a reflective layer on the surface of the glass layer subjected to the polishing treatment;
The manufacturing method of the wavelength conversion member containing this. The cross-sectional area ratio of the red phosphor in an arbitrary cross section of the first wavelength conversion layer is 54% or more;
The manufacturing method of the wavelength conversion member of Claim 8.