Wavelength conversion member, method for manufacturing same, and light-emitting device
The method of forming a wavelength conversion member with a glass matrix and selective polishing of glass layers addresses the high cost and productivity issues of existing methods, achieving cost-effective and efficient production of wavelength conversion members.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- NIPPON ELECTRIC GLASS CO LTD
- Filing Date
- 2025-12-23
- Publication Date
- 2026-07-02
AI Technical Summary
Existing methods for manufacturing wavelength conversion members using inorganic phosphor particles in glass matrices are costly due to polishing losses and require time-consuming adjustments to achieve desired chromaticity, limiting productivity.
A manufacturing method involving the formation of a phosphor layer with a glass matrix and glass layers on both sides, followed by firing and selective polishing of the glass layers to achieve the desired thickness without polishing the phosphor layer, thereby reducing material loss and simplifying chromaticity adjustments.
This method reduces manufacturing costs and enhances productivity by minimizing polishing of expensive inorganic phosphors and eliminating the need for chromaticity adjustments, while maintaining the ability to produce wavelength conversion members with consistent performance.
Smart Images
Figure JP2025044962_02072026_PF_FP_ABST
Abstract
Description
Wavelength Conversion Member, Method for Manufacturing the Same, and Light-Emitting Device
[0001] The present invention relates to a wavelength conversion member, a method for manufacturing the wavelength conversion member, and a light-emitting device using the wavelength conversion member.
[0002] Conventionally, light-emitting devices using light-emitting elements such as light-emitting diodes (LEDs: Light Emitting Diodes) and laser diodes (LDs: Laser Diodes) have been widely known. As a light-emitting device, for example, a device that uses combined light of excitation light emitted from a light source and passed through a wavelength conversion member and fluorescence emitted from a phosphor contained in the wavelength conversion member is known. A wavelength conversion member constituting such a light-emitting device is produced, for example, by polishing a glass base material in which an inorganic phosphor is dispersed in a glass matrix and adjusting the thickness and smoothness.
[0003] In Patent Document 1 below, based on the correlation between the chromaticity and the thickness of a plate-like base material containing inorganic phosphor particles, a target thickness corresponding to the target chromaticity of the obtained wavelength conversion member is determined, and the plate-like base material is polished to the target thickness, thereby A method for manufacturing a wavelength conversion member is disclosed.
[0004] Japanese Patent Application Laid-Open No. 2018-10188
[0005] In the method of polishing a plate-like base material containing inorganic phosphor particles as in Patent Document 1, since the inorganic phosphor particles themselves are also scraped off, especially when using expensive inorganic phosphor particles, the manufacturing cost increases due to polishing loss. There is a problem. Further, in the method of polishing a plate-like base material containing inorganic phosphor particles, the chromaticity may change significantly unintentionally just by scraping a little of the plate-like base material, and it may take time to adjust the chromaticity. Therefore, there are cases where the productivity of the wavelength conversion member cannot be sufficiently improved even by this method.
[0006] An object of the present invention is to provide a wavelength conversion member, a method for manufacturing the wavelength conversion member, and a light-emitting device using the wavelength conversion member that enable reduction of manufacturing cost and improvement of productivity.
[0007] The following describes a wavelength conversion member that solves the above problems, a method for manufacturing the wavelength conversion member, and various embodiments of a light-emitting device using the wavelength conversion member.
[0008] A method for manufacturing a wavelength conversion member according to Embodiment 1 of the present invention comprises a phosphor layer having a glass matrix and an inorganic phosphor dispersed in the glass matrix, a first glass layer provided on one main surface of the phosphor layer, and a second glass layer provided on the other main surface of the phosphor layer, and is characterized by comprising: a green sheet manufacturing step of producing a green sheet for forming a phosphor layer containing glass powder and inorganic phosphor particles, a first green sheet for forming a glass layer and a second green sheet for forming a glass layer containing glass powder; a firing step of producing a green sheet laminate by laminating the first green sheet for forming a glass layer on one main surface of the phosphor layer green sheet and laminating the second green sheet for forming a glass layer on the other main surface of the phosphor layer green sheet, firing the green sheet laminate to form a fired green sheet body; and a polishing step of polishing the main surfaces on both sides of the fired green sheet body to form a wavelength conversion member.
[0009] A method for manufacturing a wavelength conversion member according to aspect 2 of the present invention comprises a phosphor layer having a glass matrix and an inorganic phosphor dispersed in the glass matrix, a first glass layer provided on one main surface of the phosphor layer, and a second glass layer provided on the other main surface of the phosphor layer, and is characterized by comprising: a green sheet manufacturing step of producing a first glass layer forming green sheet and a second glass layer forming green sheet containing glass powder; a firing step of producing a phosphor layer precursor containing glass powder and inorganic phosphor particles on one main surface of the first glass layer forming green sheet, and laminating the second glass layer forming green sheet on the main surface of the phosphor layer precursor opposite to the first glass layer forming green sheet to produce a green sheet laminate, firing the green sheet laminate to form a fired green sheet body; and a polishing step of polishing the main surfaces on both sides of the fired green sheet body to form a wavelength conversion member.
[0010] In the method for manufacturing a wavelength conversion member according to Embodiment 3, in Embodiment 2, it is preferable to produce the phosphor layer precursor by applying a phosphor layer forming paste containing the glass powder and the inorganic phosphor particles onto one main surface of the first glass layer forming green sheet when producing the phosphor layer precursor.
[0011] In the method for manufacturing a wavelength conversion member according to Embodiment 4, in any one embodiment from Embodiments 1 to 3, when forming the green sheet fired body, it is preferable to form the green sheet fired body such that its thickness is greater than the target thickness of the wavelength conversion member, and in the polishing step, polish the main surfaces on both sides of the green sheet fired body to the target thickness to obtain the wavelength conversion member.
[0012] In the manufacturing method of the wavelength conversion member according to Embodiment 5, it is preferable that in the polishing step of any one Embodiment from Embodiment 1 to Embodiment 4, the main surfaces on both sides of the green sheet fired body are polished such that the thickness ratio of the thickness of the first glass layer constituting the wavelength conversion member to the thickness of the second glass layer (first glass layer / second glass layer) is 0.9 or more and 1.1 or less.
[0013] In the method for manufacturing the wavelength conversion member according to Embodiment 6, it is preferable that in the polishing step of any one Embodiment from Embodiment 1 to Embodiment 5, the main surfaces on both sides of the green sheet fired body are polished such that the thickness ratio (glass layer / phosphor layer) of the thickness of the first glass layer and the second glass layer constituting the wavelength conversion member to the thickness of the phosphor layer is 0.3 or more and 5 or less.
[0014] In the method for manufacturing the wavelength conversion member according to Embodiment 7, it is preferable to polish the main surfaces on both sides of the green sheet fired body in the polishing step of any one of Embodiments 1 to 6 such that the phosphor layer constituting the wavelength conversion member is not polished.
[0015] In the method for manufacturing a wavelength conversion member according to Embodiment 8, in any one embodiment from Embodiments 1 to 7, it is preferable that the glass powder contained in the phosphor layer forming green sheet and the glass powder contained in the first glass layer forming green sheet and the second glass layer forming green sheet have the same glass composition.
[0016] In the method for manufacturing a wavelength conversion member according to Embodiment 9, it is preferable that, in any one embodiment from Embodiments 1 to 8, the inorganic phosphor particles contained in the green sheet for forming the phosphor layer are composed of nitride phosphors or oxynitride phosphors.
[0017] A wavelength conversion member according to embodiment 10 of the present invention comprises a phosphor layer having a glass matrix and an inorganic phosphor dispersed in the glass matrix, a first glass layer provided on one main surface of the phosphor layer, and a second glass layer provided on the other main surface of the phosphor layer, characterized in that polishing marks are present on the surfaces of the first glass layer and the second glass layer.
[0018] In the wavelength conversion member according to embodiment 11, it is preferable that the inorganic phosphor contained in the phosphor layer is a nitride phosphor or an oxynitride phosphor in embodiment 10.
[0019] In the wavelength conversion member according to embodiment 12, it is preferable that the content of the inorganic phosphor in the phosphor layer is 5% by volume or more and 74% by volume or less in embodiment 10 or embodiment 11.
[0020] A light-emitting device according to embodiment 13 of the present invention is characterized by comprising a wavelength conversion member according to any one embodiment from embodiment 10 to embodiment 12, and a light source that emits excitation light to the wavelength conversion member.
[0021] According to the present invention, it is possible to provide a wavelength conversion member, a method for manufacturing the wavelength conversion member, and a light-emitting device using the wavelength conversion member, which enable a reduction in manufacturing costs and an improvement in productivity.
[0022] Figures 1(a) to 1(c) are schematic cross-sectional views illustrating a method for manufacturing a wavelength conversion member according to a first embodiment of the present invention. Figure 2 is a schematic cross-sectional view showing a wavelength conversion member according to one embodiment of the present invention. Figure 3 is a photograph showing an example of polishing marks provided on the surfaces of the first glass layer and the second glass layer in a wavelength conversion member according to one embodiment of the present invention. Figure 4 is a schematic cross-sectional view showing a light-emitting device according to one embodiment of the present invention. Figure 5 is a schematic cross-sectional view showing a modified example of the light-emitting device according to one embodiment of the present invention. Figures 6(a) to 1(c) are schematic cross-sectional views illustrating a method for manufacturing a wavelength conversion member according to a second embodiment of the present invention. Figure 7 is a schematic cross-sectional view illustrating a modified example of the method for manufacturing a wavelength conversion member according to a second embodiment of the present invention.
[0023] Preferred embodiments are described below. However, the following embodiments are merely illustrative, and the present invention is not limited to these embodiments. In addition, in each drawing, components having substantially the same function may be referred to by the same reference numerals.
[0024] [Method for Manufacturing a Wavelength Conversion Member] (First Embodiment) Figures 1(a) to 1(c) are schematic cross-sectional views illustrating the method for manufacturing a wavelength conversion member according to the first embodiment of the present invention.
[0025] In the first embodiment of the method for manufacturing the wavelength conversion member, first, a green sheet 2A for forming a phosphor layer, a green sheet 10A for forming a first glass layer, and a green sheet 20A for forming a second glass layer are prepared. The green sheet 2A for forming a phosphor layer is a green sheet containing glass powder and inorganic phosphor particles. The green sheets 10A and 20A for forming a first glass layer are green sheets containing glass powder, respectively.
[0026] In this embodiment, the glass powder contained in the phosphor layer-forming green sheet 2A and the glass powder contained in the first glass layer-forming green sheet 10A and the second glass layer-forming green sheet 20A have the same glass composition. Thus, it is desirable that the glass powder contained in the phosphor layer-forming green sheet 2A and the glass powder contained in the first glass layer-forming green sheet 10A and the second glass layer-forming green sheet 20A have the same glass composition, but they may have different glass compositions.
[0027] To prepare the green sheet 2A for phosphor layer formation, first, a first slurry containing glass powder and inorganic phosphor particles is prepared. The first slurry may also contain organic components such as binders and solvents.
[0028] Next, the prepared first slurry is applied to the support substrate to produce the phosphor layer green sheet 2A. The phosphor layer green sheet 2A can be produced, for example, by applying the prepared first slurry onto the support substrate and moving a doctor blade, which is placed at a predetermined distance from the support substrate, relative to the slurry. As the support substrate, for example, a resin film such as polyethylene terephthalate can be used.
[0029] When preparing the first glass layer forming green sheet 10A and the second glass layer forming green sheet 20A, a second slurry containing glass powder is prepared. The second slurry may also contain organic components such as binders and solvents. When preparing the first glass layer forming green sheet 10A and the second glass layer forming green sheet 20A, it is desirable to prepare a second slurry having the same composition. However, when preparing the first glass layer forming green sheet 10A and the second glass layer forming green sheet 20A, second slurries having different compositions may be prepared for each.
[0030] Next, the first glass layer forming green sheet 10A is produced by applying the prepared second slurry to the support substrate. Similarly, the second glass layer forming green sheet 20A is produced by applying the prepared second slurry to the support substrate. The first glass layer forming green sheet 10A and the second glass layer forming green sheet 20A can be produced, for example, by applying the prepared second slurry onto the support substrate and moving a doctor blade, which is installed at a predetermined distance from the support substrate, relative to the slurry. As the support substrate, for example, a resin film such as polyethylene terephthalate can be used.
[0031] The phosphor layer-forming green sheet 2A, the first glass layer-forming green sheet 10A, and the second glass layer-forming green sheet 20A may be used after heat drying. In this case, the drying temperature can be, for example, 50°C or higher and 150°C or lower. The drying time can be, for example, 5 minutes or higher and 20 minutes or lower. The phosphor layer-forming green sheet 2A, the first glass layer-forming green sheet 10A, and the second glass layer-forming green sheet 20A may also be cut into predetermined shapes as needed. In this embodiment, the phosphor layer-forming green sheet 2A, the first glass layer-forming green sheet 10A, and the second glass layer-forming green sheet 20A are cut into rectangular shapes of the same size. Of course, the phosphor layer-forming green sheet 2A, the first glass layer-forming green sheet 10A, and the second glass layer-forming green sheet 20A may also be cut into shapes other than rectangles.
[0032] Next, as shown in Figure 1(a), a first glass layer forming green sheet 10A is laminated onto one main surface 2Aa of the phosphor layer forming green sheet 2A. A second glass layer forming green sheet 20A is then laminated onto the other main surface 2Ab of the phosphor layer forming green sheet 2A. This completes the production of a green sheet laminate 1A.
[0033] In this case, it is preferable to produce the green sheet laminate 1A by heat-pressing the first glass layer forming green sheet 10A and the second glass layer forming green sheet 20A on the main surfaces 2Aa and 2Ab on both sides of the phosphor layer forming green sheet 2A, respectively. The heat-pressing temperature can be, for example, 30°C or higher and 100°C or lower. The heat-pressing time can be, for example, 1 minute or higher and 20 minutes or lower. The heat-pressing pressure can be, for example, 5 MPa or higher and 30 MPa or lower.
[0034] Next, the green sheet laminate 1A is fired to form the green sheet fired body 1B shown in Figure 1(b). As shown in Figure 1(b), in the green sheet fired body 1B, a first glass layer 10B and a second glass layer 20B are formed on the main surfaces 2a and 2b on both sides of the phosphor layer 2, respectively.
[0035] The lower limit of the firing temperature of the green sheet laminate 1A is not particularly limited, but for example, it is above the softening point of the glass powder, preferably higher than the softening point of the glass powder, and more preferably above the softening point of the glass powder + 30°C. The upper limit of the firing temperature of the green sheet laminate 1A is not particularly limited, but for example, it is preferably below the softening point of the glass powder + 150°C, more preferably below the softening point of the glass powder + 100°C, even more preferably below the softening point of the glass powder + 90°C, even more preferably below the softening point of the glass powder + 80°C, even more preferably below the softening point of the glass powder + 70°C, even more preferably below the softening point of the glass powder + 60°C, even more preferably below the softening point of the glass powder + 50°C, even more preferably below the softening point of the glass powder + 40°C, even more preferably below the softening point of the glass powder + 30°C, particularly preferably below the softening point of the glass powder + 20°C, and most preferably below the softening point of the glass powder + 10°C.
[0036] If the firing temperature of the green sheet laminate 1A is too low, the glass powder will not flow sufficiently, making it difficult to obtain a dense sintered body. On the other hand, if the firing temperature of the green sheet laminate 1A is too high, the inorganic phosphor particles may degrade due to heat, or foaming may occur due to the reaction between the inorganic phosphor particles and the glass powder, potentially reducing the luminescence intensity and mechanical strength of the resulting wavelength conversion member. Furthermore, if the firing temperature of the green sheet laminate 1A is too high, the inorganic phosphor particles may dissolve into the glass matrix, reducing the luminescence intensity of the wavelength conversion member, or the inorganic phosphor particles may diffuse into the glass matrix, causing the glass matrix to become discolored and further reducing the luminescence intensity of the wavelength conversion member.
[0037] The firing atmosphere for the green sheet laminate 1A is preferably a reduced pressure atmosphere, and more preferably a vacuum atmosphere. However, the firing atmosphere for the green sheet laminate 1A may also be under atmospheric pressure or a nitrogen atmosphere. The firing time for the green sheet laminate 1A can be, for example, 10 minutes or more and 60 minutes or less. The firing time referred to here is the time during which the green sheet laminate 1A remains in a temperature range above the softening point of the glass powder.
[0038] Next, the main surfaces 1Ba and 1Bb on both sides of the green sheet fired body 1B shown in Figure 1(b) are polished to form the wavelength conversion member 1 shown in Figure 1(c) (hereinafter, this process may be referred to as the polishing process). Specifically, the main surface 10Ba side of the first glass layer 10B shown in Figure 1(b) that is opposite to the phosphor layer 2 side, and the main surface 20Ba side of the second glass layer 20B that is opposite to the phosphor layer 2 side are polished. By doing so, the thickness of the first glass layer 10B and the second glass layer 20B is reduced, and the wavelength conversion member 1 shown in Figure 1(c) is formed by creating the first glass layer 10 and the second glass layer 20.
[0039] Examples of polishing methods for the green sheet fired body 1B include lapping and mirror polishing. Lapping has the advantage of being faster than mirror polishing. On the other hand, mirror polishing has the advantage of being able to produce a better surface finish than lapping. The polishing method for the green sheet fired body 1B should be appropriately determined according to the application in which the resulting wavelength conversion member 1 will be used.
[0040] In the manufacturing method of the wavelength conversion member 1 of this embodiment, the wavelength conversion member 1 is formed by polishing the main surfaces 1Ba and 1Bb on both sides of the green sheet firing body 1B, that is, the first glass layer 10B and the second glass layer 20B that constitute the green sheet firing body 1B. Therefore, the surface properties and thickness of the obtained wavelength conversion member 1 can be adjusted without polishing the phosphor layer 2. Thus, in the manufacturing method of the wavelength conversion member 1 of this embodiment, since the wavelength conversion member 1 can be manufactured without polishing the phosphor layer 2, polishing loss of the inorganic phosphor 4 contained in the phosphor layer 2 is less likely to occur, and manufacturing costs can be reduced. Furthermore, in the manufacturing method of the wavelength conversion member 1 of this embodiment, since the wavelength conversion member 1 can be manufactured without polishing the phosphor layer 2, it is not necessary to consider the effect on the chromaticity of the obtained wavelength conversion member 1, as in the case where the phosphor layer 2 is polished, and thus the productivity of the wavelength conversion member 1 can be increased. Therefore, in the manufacturing method of the wavelength conversion member 1 of this embodiment, it is desirable to polish the main surfaces 1Ba and 1Bb on both sides of the green sheet fired body 1B so as not to polish the phosphor layer 2 that constitutes the wavelength conversion member 1.
[0041] In this embodiment, when forming the green sheet fired body 1B, it is preferable to form the green sheet fired body 1B to a thickness greater than the target thickness T of the wavelength conversion member 1, and then in the polishing process, polish the main surfaces 1Ba and 1Bb on both sides of the green sheet fired body 1B to the target thickness T to obtain the wavelength conversion member 1. In this case, the wavelength conversion member 1 with the target thickness T can be easily formed, and the productivity of the obtained wavelength conversion member 1 can be further increased. In this embodiment, the thickness T4 of the green sheet fired body 1B is increased by increasing the thickness T5 of the first glass layer 10B and the thickness T6 of the second glass layer 20B.
[0042] In this embodiment, in the polishing process, it is preferable to polish the main surfaces 1Ba and 1Bb on both sides of the green sheet fired body 1B so that the thickness ratio (T2 / T3) of the thickness T2 of the first glass layer 10 constituting the obtained wavelength conversion member 1 to the thickness T3 of the second glass layer 20 is 0.9 or more and 1.1 or less. In this case, warping of the obtained wavelength conversion member 1 can be further suppressed. In particular, when a nitride phosphor or oxynitride phosphor having a rod shape such as α-sialon is used as the inorganic phosphor 4, warping is likely to occur in the wavelength conversion member 1 after firing. Therefore, when a nitride phosphor or oxynitride phosphor having a rod shape such as α-sialon is used as the inorganic phosphor 4, it is particularly preferable to polish the main surfaces 1Ba and 1Bb on both sides of the green sheet fired body 1B so that the thickness ratio (T2 / T3) is within the above range. Furthermore, it is more preferable to polish the main surfaces 1Ba and 1Bb on both sides of the green sheet fired body 1B so that the thickness T2 of the first glass layer 10 and the thickness T3 of the second glass layer 20 constituting the resulting wavelength conversion member 1 are the same.
[0043] In this embodiment, it is preferable to polish the main surfaces 1Ba and 1Bb on both sides of the green sheet fired body 1B such that the thickness ratio (T2 or T3 / T1) of the thickness (T1) of the first glass layer 10 and the second glass layer 20 constituting the wavelength conversion member 1 to the thickness (T1) of the phosphor layer 2 is 0.3 or more and 5 or less. Furthermore, it is desirable to polish the main surfaces 1Ba and 1Bb on both sides of the green sheet fired body 1B such that the thickness ratio (T2 or T3 / T1) is more preferably 0.4 or more, even more preferably 0.5 or more, particularly preferably 0.6 or more, more preferably 4 or less, even more preferably 3 or less, and particularly preferably 2 or less. If the thickness ratio (T2 or T3 / T1) is smaller than the above lower limit, the thickness of the first glass layer 10 and the second glass layer 20 will be thinner, which may reduce their strength. Furthermore, if the thickness ratio (T2 or T3 / T1) is greater than the above upper limit, the thickness of the phosphor layer 2 becomes thin, making it difficult to adequately convert excitation light A into fluorescence B, and thus making it difficult to adjust the emitted light to the target chromaticity.
[0044] The wavelength conversion member 1 obtained by the manufacturing method of the wavelength conversion member 1 of this embodiment may be used to extract composite light of excitation light and fluorescence having the emission peak wavelength of the inorganic phosphor 4, or it may be used to extract only fluorescence having the emission peak wavelength of the inorganic phosphor 4. When the wavelength conversion member 1 is used to extract only fluorescence having the emission peak wavelength of the inorganic phosphor 4, the chromaticity of the wavelength conversion member 1 will not change significantly even if the thickness of the phosphor layer 2 changes somewhat, as long as the concentration of the inorganic phosphor 4 is increased to a certain extent. Therefore, since there is no need to adjust the chromaticity by polishing the phosphor layer 2 during the manufacturing of the wavelength conversion member 1, the manufacturing method of the wavelength conversion member 1 of this embodiment, which polishes the first glass layer 10B and the second glass layer 20B, can be suitably used when the wavelength conversion member 1 extracts only fluorescence having the emission peak wavelength of the inorganic phosphor 4. Examples of inorganic phosphor 4 used when the wavelength conversion member 1 extracts only fluorescence having the emission peak wavelength of the inorganic phosphor 4 include nitride phosphors such as α-sialon or oxynitride phosphors. Therefore, nitride phosphors such as α-sialon can be suitably used in the method for manufacturing the wavelength conversion member 1 of this embodiment.
[0045] (Second Embodiment) Figures 6(a) to 6(c) are schematic cross-sectional views illustrating a method for manufacturing a wavelength conversion member according to a second embodiment of the present invention.
[0046] In the second embodiment of the method for manufacturing the wavelength conversion member, first, a first glass layer forming green sheet 10A and a second glass layer forming green sheet 20A are prepared. The first glass layer forming green sheet 10A and the second glass layer forming green sheet 20A can be the same as those used in the first embodiment of the method for manufacturing the wavelength conversion member. The second embodiment of the method for manufacturing the wavelength conversion member differs from the first embodiment in that a phosphor layer forming green sheet 2A is not prepared in advance.
[0047] In the second embodiment of the method for manufacturing the wavelength conversion member, as shown in Figure 6(a), a phosphor layer precursor 2B containing glass powder and inorganic phosphor particles is prepared on one main surface of the first glass layer forming green sheet 10A. When preparing the phosphor layer precursor 2B, it is preferable to prepare the phosphor layer precursor 2B by applying a phosphor layer forming paste containing glass powder and inorganic phosphor particles to one main surface of the first glass layer forming green sheet 10A. When the phosphor layer precursor 2B is prepared using a phosphor layer forming paste, it is possible to easily adjust the thickness of the final phosphor layer 2. Note that the phosphor layer precursor 2B is a layer for forming the phosphor layer 2, and refers to a layer as a preliminary step before firing of the phosphor layer 2.
[0048] In this embodiment, the glass powder contained in the phosphor layer precursor 2B and the paste for forming the phosphor layer has the same glass composition as the glass powder contained in the first glass layer forming green sheet 10A and the second glass layer forming green sheet 20A. Thus, it is desirable that the glass powder contained in the phosphor layer precursor 2B and the paste for forming the phosphor layer has the same glass composition as the glass powder contained in the first glass layer forming green sheet 10A and the second glass layer forming green sheet 20A, but they may have different glass compositions.
[0049] When preparing a paste for forming a phosphor layer, it is sufficient to prepare a paste by mixing glass powder and inorganic phosphor particles. However, if it is desirable to suppress excessive impact on the inorganic phosphor particles, it is preferable to prepare a paste of glass powder and a paste of inorganic phosphor particles separately, and then mix them to prepare the paste for forming the phosphor layer. In this case, the mixing method can be applied to pastes of inorganic phosphor particles that are easily crushed, such as those having a rod-like shape, while minimizing impact. This suppresses the crushing of the inorganic phosphor particles, and further increases the emission intensity of light emitted from the resulting wavelength conversion member 1.
[0050] When preparing a glass powder paste, for example, the glass powder and the vehicle can be mixed and then uniformly kneaded to obtain the glass powder paste. The kneading method is not particularly limited, and for example, it can be kneaded in a three-roll mill. The vehicle is not particularly limited, and for example, ethyl cellulose dissolved in α-terpineol can be used. Furthermore, it is preferable to adjust the mixing ratio of glass powder to vehicle by mass to 2 to 3.
[0051] In preparing the inorganic phosphor particle paste, the inorganic phosphor particles and the vehicle are mixed and then uniformly kneaded to obtain the inorganic phosphor particle paste. The vehicle is not particularly limited, and for example, ethyl cellulose dissolved in α-terpineol can be used. The mixing ratio of inorganic phosphor particles to vehicle is preferably adjusted to a mass ratio of 2 to 3 for inorganic phosphor particles / vehicle. The kneading method is not particularly limited, but it is preferable to use a rotation-orbit type mixer. In this case, the impact during kneading can be suppressed, so the crushing of inorganic phosphor particles that are easily crushed, such as those having a rod shape, can be suppressed, and the emission intensity of light emitted from the resulting wavelength conversion member 1 can be further increased.
[0052] Next, the obtained glass powder paste and the inorganic phosphor particle paste are kneaded together. This yields a paste for forming the phosphor layer. The mixing ratio of the glass powder paste and the inorganic phosphor particle paste can be appropriately set according to the composition of the resulting phosphor layer 2. For example, the mixing ratio of the glass powder paste and the inorganic phosphor particle paste can be 4:6 by volume. The method of kneading the glass powder paste and the inorganic phosphor particle paste is not particularly limited, but for example, a rotary-orbit mixer can be used. The mixing ratio of the composite powder of glass powder and inorganic phosphor particles to the vehicle is preferably adjusted to a mass ratio of composite powder / vehicle of 2 to 3.
[0053] The method for applying the paste for forming the phosphor layer is not particularly limited, and can be applied using, for example, an applicator, a doctor blade, or a screen printing method.
[0054] The phosphor layer precursor 2B may be used after heat drying. In this case, the drying temperature can be, for example, 100°C or higher and 300°C or lower. The drying time can be, for example, 10 minutes or higher and 60 minutes or lower.
[0055] Next, as shown in Figure 6(b), with the first glass layer forming green sheet 10A placed on one main surface 2Baa of the phosphor layer precursor 2B, the second glass layer forming green sheet 20A is laminated on the other main surface 2Bb of the phosphor layer precursor 2B. This creates a green sheet laminate 1C.
[0056] In this case, it is preferable to produce the green sheet laminate 1C by heat-pressing the first glass layer forming green sheet 10A and the second glass layer forming green sheet 20A on the main surfaces 2Ba and 2Bb on both sides of the phosphor layer precursor 2B, respectively. The heat-pressing temperature can be, for example, 30°C or higher and 100°C or lower. The heat-pressing time can be, for example, 1 minute or higher and 20 minutes or lower. The heat-pressing pressure can be, for example, 5 MPa or higher and 30 MPa or lower.
[0057] Furthermore, before laminating the second glass layer-forming green sheet 20A, any portions of the phosphor layer precursor 2B with uneven thickness may be pre-cut. Doing so makes it easier to apply a uniform load during thermocompression bonding, further reducing the likelihood of delamination and allowing for the production of a high-quality wavelength conversion member 1.
[0058] In the second embodiment of the method for manufacturing the wavelength conversion member, the wavelength conversion member 1 shown in Figure 6(c) can be obtained in the same manner as the method for manufacturing the wavelength conversion member in the first embodiment (through firing and polishing processes in the same manner as in the first embodiment), except that the green sheet laminate 1C manufactured in this manner is used in place of the green sheet laminate 1A in the first embodiment.
[0059] As shown in the modified example in Figure 7, the green sheet laminate 1C may be fired with both sides sandwiched between restraining green sheets 11 and 21. For example, the restraining green sheets 11 and 21 can be made of alumina or the like. After firing, the resulting restraining layer can be removed by, for example, ultrasonic cleaning. When using restraining green sheets 11 and 21, a wavelength conversion member 1 with even less warping can be obtained.
[0060] The wavelength conversion member 1 obtained by the manufacturing method of the second embodiment may be used to extract composite light of excitation light and fluorescence having the emission peak wavelength of the inorganic phosphor 4, or it may be used to extract only fluorescence having the emission peak wavelength of the inorganic phosphor 4. When the wavelength conversion member 1 is used to extract only fluorescence having the emission peak wavelength of the inorganic phosphor 4, the chromaticity of the wavelength conversion member 1 will not change significantly even if the thickness of the phosphor layer 2 changes somewhat, as long as the concentration of the inorganic phosphor 4 is increased to a certain extent. Therefore, since there is no need to adjust the chromaticity by polishing the phosphor layer 2 during the manufacturing of the wavelength conversion member 1, the manufacturing method of the wavelength conversion member 1 of the second embodiment, in which the first glass layer 10B and the second glass layer 20B are polished, can be suitably used when the wavelength conversion member 1 extracts only fluorescence having the emission peak wavelength of the inorganic phosphor 4. Examples of inorganic phosphor 4 used when the wavelength conversion member 1 extracts only fluorescence having the emission peak wavelength of the inorganic phosphor 4 include nitride phosphors such as α-sialon or oxynitride phosphors. Therefore, nitride phosphors such as α-sialon can also be suitably used in the manufacturing method of the wavelength conversion member 1 of the second embodiment.
[0061] [Wavelength Conversion Member] Figure 2 is a schematic cross-sectional view showing a wavelength conversion member according to one embodiment of the present invention.
[0062] As shown in Figure 2, the wavelength conversion member 1 has a first main surface 1a and a second main surface 1b facing each other. In this embodiment, the first main surface 1a of the wavelength conversion member 1 is the light incident surface on which the excitation light A emitted from the light source 30 enters the wavelength conversion member 1. The second main surface 1b of the wavelength conversion member 1 is the light emission surface on which the fluorescence B is emitted from the wavelength conversion member 1.
[0063] In this embodiment, the wavelength conversion member 1 has a rectangular plate shape. However, the shape of the wavelength conversion member 1 is not particularly limited, and for example, it may have a disc shape. The first main surface 1a of the wavelength conversion member 1 may be the light incident surface and does not necessarily have to be planar. The second main surface 1b of the wavelength conversion member 1 may be the light emission surface and does not necessarily have to be planar.
[0064] The wavelength conversion member 1 comprises a phosphor layer 2, a first glass layer 10, and a second glass layer 20. The phosphor layer 2 has opposing first main surfaces 2a and second main surfaces 2b. The first glass layer 10 is provided on the first main surface 2a of the phosphor layer 2. The first glass layer 10 is provided on the side of the first main surface 1a, which is the light incident surface of the wavelength conversion member 1. The second glass layer 20 is provided on the second main surface 2b of the phosphor layer 2. The second glass layer 20 is provided on the side of the second main surface 1b, which is the light emission surface of the wavelength conversion member 1.
[0065] The phosphor layer 2 comprises a glass matrix 3 and an inorganic phosphor 4. In the phosphor layer 2, the inorganic phosphor 4 is dispersed in the glass matrix 3.
[0066] As shown in Figure 2, in the wavelength conversion member 1, excitation light A emitted from the light source 30 enters the wavelength conversion member 1 from the first main surface 1a side. The excitation light A that enters the wavelength conversion member 1 is irradiated onto the inorganic phosphor 4 contained within the wavelength conversion member 1. The excitation light A irradiated onto the inorganic phosphor 4 is converted to another wavelength by the inorganic phosphor 4 and emitted from the second main surface 1b side of the wavelength conversion member 1 as fluorescence B having the emission peak wavelength of the inorganic phosphor 4. The light emitted from the second main surface 1b side of the wavelength conversion member 1 may be a composite light of excitation light A and fluorescence B, or fluorescence B itself, but as described above, it is preferable that it be fluorescence B itself.
[0067] Since the wavelength conversion member 1 of this embodiment is manufactured by the method for manufacturing the wavelength conversion member 1 described above, the surface of the first glass layer 10 (first main surface 1a) and the surface of the second glass layer 20 (second main surface 1b) have polishing marks. As shown in Figure 3 as an example, the polishing marks provided on the surfaces of the first glass layer 10 and the second glass layer 20 have a streaky shape. The polishing marks provided on the surfaces of the first glass layer 10 and the second glass layer 20 may have a fine uneven shape.
[0068] Since the wavelength conversion member 1 of this embodiment is manufactured by the method for manufacturing the wavelength conversion member 1 described above, manufacturing costs can be reduced and productivity can be increased. The wavelength conversion member 1 may be manufactured using either the manufacturing method of the first embodiment or the manufacturing method of the second embodiment described above.
[0069] The following provides a more detailed explanation of each component that makes up the wavelength conversion member 1.
[0070] (First glass layer and second glass layer) The first glass layer 10 and the second glass layer 20 each have a rectangular plate shape. However, the shapes of the first glass layer 10 and the second glass layer 20 are not particularly limited, and an appropriate shape can be selected according to the shape of the wavelength conversion member 1.
[0071] The thickness ratio (T2 / T3) of the thickness T2 of the first glass layer 10 to the thickness T3 of the second glass layer 20 is preferably 0.9 or more and 1.1 or less, and more preferably the thickness T2 of the first glass layer 10 and the thickness T3 of the second glass layer 20 are the same. In this case, the warping of the wavelength conversion member 1 can be further suppressed. In particular, when a nitride phosphor or oxynitride phosphor having a rod shape such as α-sialon is used as the inorganic phosphor 4, warping is likely to occur in the wavelength conversion member 1, so when a nitride phosphor having a rod shape such as α-sialon is used as the inorganic phosphor 4, it is especially preferable that the thickness ratio (T2 / T3) is within the above range.
[0072] The thickness T2 of the first glass layer 10 is preferably 0.01 mm or more, more preferably 0.02 mm or more, preferably 0.2 mm or less, and more preferably 0.1 mm or less. The thickness T3 of the second glass layer 20 is preferably 0.01 mm or more, more preferably 0.02 mm or more, preferably 0.2 mm or less, and more preferably 0.1 mm or less.
[0073] The first glass layer 10 and the second glass layer 20 are preferably transparent. The total light transmittance of the first glass layer 10 and the second glass layer 20 at wavelengths of 380 nm to 780 nm and a thickness of 0.2 mm is preferably 50% or more, more preferably 75% or more. The upper limit of the total light transmittance is not particularly limited, but in reality it is 100% or less.
[0074] It is desirable that the first glass layer 10 and the second glass layer 20 have the same glass composition. However, the first glass layer 10 and the second glass layer 20 may have different glass compositions, and are not particularly limited. The glass constituting the first glass layer 10 and the second glass layer 20 will be described in more detail below.
[0075] Examples of glass include borosilicate glass, phosphate glass, tin phosphate glass, bismuthate glass, or tellurite glass.
[0076] Preferably, the glass has a low content of alkali metal components. Specifically, Li in the glass ２ O + Na ２ O+K ２ The O content is preferably 0% to 10% in mole percent, more preferably 0% to 5%, and even more preferably 0% to 3%. In this case, the formation of colored centers that serve as absorption sources for excitation light A and fluorescence B in the glass can be suppressed, and the decrease in the emission intensity of light emitted from the wavelength conversion member 1 can be suppressed. In addition, in this case, the deterioration of the glass over time under high temperature and high humidity conditions can also be suppressed.
[0077] The softening point of the glass is preferably 250°C to 1000°C, more preferably 300°C to 950°C, and even more preferably 500°C to 900°C.
[0078] The softening point of the glass is preferably 500°C or higher, more preferably 550°C or higher, even more preferably 600°C or higher, even more preferably 650°C or higher, even more preferably 700°C or higher, even more preferably 750°C or higher, particularly preferably 800°C or higher, and most preferably 820°C or higher. Examples of such glass include borosilicate glass. When the softening point of the glass is above the lower limit of the above value, the mechanical strength and chemical durability of the wavelength conversion member 1 can be further improved. In this case, the heat resistance of the glass itself can be further improved, and the softening deformation of the glass due to the heat generated from the inorganic phosphor 4 can be further suppressed.
[0079] Furthermore, the softening point of the glass is preferably 900°C or lower, more preferably 850°C or lower, even more preferably 840°C or lower, even more preferably 830°C or lower, even more preferably 820°C or lower, even more preferably 810°C or lower, even more preferably 800°C or lower, even more preferably 790°C or lower, even more preferably 780°C or lower, even more preferably 760°C or lower, even more preferably 750°C or lower, even more preferably 700°C or lower, even more preferably 650°C or lower, even more preferably 600°C or lower, even more preferably 550°C or lower, even more preferably 530°C or lower, even more preferably 500°C or lower, particularly preferably 480°C or lower, and most preferably 460°C or lower. Examples of such glass include borosilicate glass, tin phosphate glass, bismuthate glass, or tellurite glass. When the softening point of the glass is below the above upper limit, the firing temperature during the manufacture of the wavelength conversion member 1 can be further reduced, thereby suppressing the manufacturing cost of the wavelength conversion member 1. Furthermore, in this case, the degradation of the inorganic phosphor 4 due to the firing process during the manufacturing of the wavelength conversion member 1 is suppressed, which further suppresses the decrease in the emission intensity of light emitted from the wavelength conversion member 1.
[0080] The first glass layer 10 and the second glass layer 20 may each contain other additives. Examples of other additives include light-diffusing materials such as alumina, silica, titania, or magnesia. The content of each of the other additives in the first glass layer 10 and the second glass layer 20 is not particularly limited as long as it does not hinder the effects of the present invention, but can be, for example, 3% by volume or less. It is preferable that the first glass layer 10 and the second glass layer 20 are substantially free of inorganic phosphors. Substantially free of inorganic phosphors means that the content of inorganic phosphors in the first glass layer 10 and the second glass layer 20 is, for example, 0.1% by volume or less, and they may contain no inorganic phosphors at all.
[0081] (Phosphor Layer) The phosphor layer 2 has a rectangular plate shape. However, the shape of the phosphor layer 2 is not particularly limited, and an appropriate shape can be selected according to the shape of the wavelength conversion member 1.
[0082] The thickness ratio (T2 or T3 / T1) of the respective thicknesses (T2 or T3) of the first glass layer 10 and the second glass layer 20 to the thickness (T1) of the phosphor layer 2 is preferably 0.3 or more, more preferably 0.4 or more, even more preferably 0.5 or more, particularly preferably 0.6 or more, preferably 5 or less, more preferably 4 or less, even more preferably 3 or less, and particularly preferably 2 or less. If the thickness ratio (T2 or T3 / T1) is smaller than the lower limit, the respective thicknesses of the first glass layer 10 and the second glass layer 20 become too thin, which may reduce their strength. Also, if the thickness ratio (T2 or T3 / T1) is greater than the upper limit, the thickness of the phosphor layer 2 becomes too thin, which may prevent sufficient conversion of excitation light A into fluorescence B, making it difficult to adjust the emitted light to the target chromaticity.
[0083] The thickness T1 of the phosphor layer 2 is preferably 0.03 mm or more, more preferably 0.05 mm or more, preferably 0.2 mm or less, more preferably 0.15 mm or less, and may be 0.10 mm or less, 0.05 mm or less, or 0.03 mm or less as needed.
[0084] The phosphor layer 2 comprises a glass matrix 3 and an inorganic phosphor 4. The glass matrix 3 is preferably transparent. The light transmittance of the glass matrix 3 at wavelengths of 380 nm to 780 nm and a thickness of 0.2 mm is preferably 50% or more, more preferably 75% or more. The upper limit of the above light transmittance is not particularly limited, but in reality it is 100% or less.
[0085] It is desirable that the glass matrix 3 has the same glass composition as the first glass layer 10 and the second glass layer 20. However, the glass matrix 3 may have a different glass composition from the first glass layer 10 and the second glass layer 20, and is not particularly limited. The glass used to constitute the glass matrix 3 can be the same type of glass as that described in the sections on the first glass layer 10 and the second glass layer 20.
[0086] The inorganic phosphor 4 is not particularly limited as long as it emits fluorescence B upon incidence of excitation light A. Examples of inorganic phosphors 4 include oxide phosphors, nitride phosphors, oxynitride phosphors, chloride phosphors, acid chloride phosphors, sulfide phosphors, oxysulfide phosphors, halide phosphors, chalcogenide phosphors, aluminate phosphors, halophosphate chloride phosphors, or garnet compound phosphors. These inorganic phosphors may be used individually or in combination. In particular, as described above, it is preferable to use nitride phosphors or oxynitride phosphors such as α-sialon.
[0087] As the inorganic phosphor 4, phosphor particles coated with an oxide or the like may be used. In this case, the activation of electron, hole, or alkali ion movement in the glass matrix 3 can be suppressed, and as a result, the formation of colored centers can be suppressed. In addition, in this case, the conduction of heat generated from the inorganic phosphor 4 to the glass matrix 3 can be suppressed.
[0088] As the inorganic phosphor 4, a phosphor having an excitation band between 300 nm and 500 nm and an emission peak between 500 nm and 780 nm is preferably used, and in particular, phosphors that emit green (wavelength 500 nm to 540 nm), yellow (wavelength 540 nm to 595 nm), and red (wavelength 600 nm to 700 nm) light can be used.
[0089] As an inorganic phosphor having an excitation band in the ultraviolet to near-ultraviolet wavelength range of 300 nm to 440 nm and a green emission peak, SrAl ２ O ４ :Eu ２＋ , SrBaSiO ４ :Eu ２＋, Y ３ (Al, Gd) ５ O １２ : Ce ３＋ , SrSiO N:Eu ２＋ , BaMgAl １０ O １７ : Eu ２＋ , Mn ２＋ , Ba ２ MgSi ２ O ７ : Eu ２＋ , Ba ２ SiO ４ : Eu ２＋ , Ba ２ Li ２ Si ２ O ７ : Eu ２＋ , BaAl ２ O ４ : Eu ２＋ etc. can be mentioned.
[0090] As an inorganic phosphor having an excitation band between wavelengths of 440 nm and 480 nm, which is the blue wavelength region, and having a green emission peak, SrAl ２ O ４ : Eu ２＋ , Lu ３ Al ５ O １２ : Ce, SrBaSiO ４ : Eu ２＋ , Y ３ (Al, Gd) ５ O １２ : Ce ３＋ , SrSiO N:Eu ２＋ , β-SiAlON:Eu ２＋ etc. can be mentioned.
[0091] As an inorganic phosphor having an excitation band between wavelengths of 300 nm and 440 nm, which is the ultraviolet to near-ultraviolet wavelength region, and having a yellow emission peak, La ３ Si ６ N １１ : Ce ３＋ etc. can be mentioned.
[0092] As an inorganic phosphor having an excitation band between wavelengths of 440 nm and 480 nm, which is the blue wavelength region, and having a yellow emission peak, Y ３ (Al, Gd) ５O １２ : Ce ３＋ Lu ３ Al ５ O １２ : Ce, Sr ２ SiO ４ :Eu ２＋ These are some examples.
[0093] As an inorganic phosphor having an excitation band in the ultraviolet to near-ultraviolet wavelength range of 300 nm to 440 nm and a red emission peak, MgSr ３ Si ２ O ８ :Eu ２＋ , Mn ２＋ Ca ２ MgSi ２ O ７ :Eu ２＋ , Mn ２＋ These are some examples.
[0094] As an inorganic phosphor having an excitation band in the blue wavelength range of 440 nm to 480 nm and a yellow to red, so-called amber emission peak, CaAlSiN is an example. ３ :Eu ２＋ (CASN), (Ca,Sr)AlSiN ３ :Eu ２＋ (SCASN), CaSiN ３ :Eu ２＋ (Ca, Sr) ２ Si ５ N ８ :Eu ２＋ , α-SiAlON:Eu ２＋ Ba ２ Si ５ N ８ :Eu ２＋ Examples include Ce-activated CALSON phosphors.
[0095] The refractive index of the inorganic phosphor 4 is often higher than that of the glass matrix 3. In the wavelength conversion member 1, if the refractive index difference between the inorganic phosphor 4 and the glass matrix 3 is large, the excitation light A is more likely to scatter at the interface between the inorganic phosphor 4 and the glass matrix 3. As a result, the irradiation efficiency of the excitation light A to the inorganic phosphor 4 increases, and the luminescence efficiency of the inorganic phosphor 4 tends to improve. However, if the refractive index difference between the inorganic phosphor 4 and the glass matrix 3 is too large, the scattering of the excitation light A becomes excessive, resulting in scattering loss and conversely, the luminescence efficiency of the inorganic phosphor 4 tends to decrease.
[0096] Considering these factors, the refractive index difference between the inorganic phosphor 4 and the glass matrix 3 is preferably 0.001 to 0.6. Furthermore, the refractive index (nd) of the glass matrix 3 is preferably 1.45 to 1.8, more preferably 1.47 to 1.75, and even more preferably 1.48 to 1.7.
[0097] The average particle diameter of the inorganic phosphor 4 is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, preferably 30 μm or less, more preferably 25 μm or less, and even more preferably 20 μm or less. When the average particle diameter of the inorganic phosphor 4 is greater than or equal to the lower limit, the emission intensity of the light emitted from the wavelength conversion member 1 can be further increased. Also, when the average particle diameter of the inorganic phosphor 4 is less than or equal to the upper limit, the dispersibility of the inorganic phosphor 4 in the glass matrix 3 can be further increased, and the emission color of the light emitted from the wavelength conversion member 1 can be made even more uniform. In this specification, the average particle diameter is the particle diameter D at which the cumulative frequency is 50 volume% in the volume-based particle size distribution measured by a laser diffraction particle size distribution analyzer. ５０ This refers to the following.
[0098] The content of inorganic phosphor 4 in the phosphor layer 2 is preferably 5% by volume or more, more preferably 10% by volume or more, even more preferably 20% by volume or more, preferably 74% by volume or less, more preferably 60% by volume or less, and even more preferably 50% by volume or less. As described above, when the wavelength conversion member 1 is used to extract only the fluorescence having the emission peak wavelength of the inorganic phosphor 4, if the concentration (content) of inorganic phosphor 4 is made somewhat large, the chromaticity will not change significantly even if the thickness of the phosphor layer 2 changes somewhat. Therefore, when the content of inorganic phosphor 4 is within the above range, it can be suitably used in the manufacturing method of the wavelength conversion member 1 described above.
[0099] The phosphor layer 2 may contain other additives in addition to the inorganic phosphor 4. Examples of other additives include light-diffusing materials such as alumina, silica, or magnesia. The content of each of the other additives in the phosphor layer 2 is not particularly limited as long as it does not hinder the effects of the present invention, but can be, for example, 3% by volume or less.
[0100] (Wavelength Conversion Member) The thickness T of the wavelength conversion member 1 is preferably 0.05 mm or more, more preferably 0.1 mm or more, preferably 0.5 mm or less, and more preferably 0.2 mm or less. When the thickness T of the wavelength conversion member 1 is greater than or equal to the lower limit, the emission intensity of the light emitted from the wavelength conversion member 1 can be further increased. Also, when the thickness T of the wavelength conversion member 1 is less than or equal to the upper limit, the wavelength conversion member 1 can be miniaturized.
[0101] The surface roughness Ra of the first main surface 1a and the second main surface 1b of the wavelength conversion member 1 is preferably 5 nm or more, more preferably 10 nm or more, preferably 500 nm or less, and more preferably 100 nm or less, respectively. Surface roughness Ra refers to the arithmetic mean roughness Ra as defined in JIS B0601-2001.
[0102] The first main surface 1a and the second main surface 1b of the wavelength conversion member 1 may be provided with a functional film such as a reflective film, an anti-reflective film, or a filter film. For example, conventionally known dielectric multilayer films can be used as these functional films.
[0103] The wavelength conversion member 1 can be suitably used as a component of general lighting such as white LEDs, or special lighting (for example, projector light sources, automotive headlights, turn signals, and other automotive lighting).
[0104] [Light-emitting device] Figure 4 is a schematic cross-sectional view showing a light-emitting device according to one embodiment of the present invention. As shown in Figure 4, the light-emitting device 31 comprises a wavelength conversion member 1 according to the first embodiment described above, and a light source 30 that emits excitation light A to the wavelength conversion member 1. In the light-emitting device 31, the light source 30 is arranged so that the excitation light A is directly incident on the wavelength conversion member 1.
[0105] Figure 5 is a schematic cross-sectional view showing a modified example of a light-emitting device according to one embodiment of the present invention. As shown in Figure 5, in the light-emitting device 41, a light guide plate 42 is arranged between the light source 30 and the wavelength conversion member 1. The light source 30 is arranged so that the excitation light A is directly incident on the light guide plate 42. The excitation light A emitted from the light source 30 passes through the light guide plate 42 and is incident on the wavelength conversion member 1. Specifically, the excitation light A is incident from the end face of the light guide plate 42, exits from the main surface of the light guide plate 42, and is incident on the wavelength conversion member 1. A material with low absorption of excitation light A can be used as the light guide plate 42. In addition, the light guide plate 42 and the wavelength conversion member 1 may be joined together.
[0106] Since the light-emitting devices 31 and 41 are equipped with the wavelength conversion member 1 described above, manufacturing costs can be reduced and productivity can be increased.
[0107] 1...Wavelength conversion member 1a, 2a...First main surface (main surface) 1b, 2b...Second main surface (main surface) 1A, 1C...Green sheet laminate 1B...Green sheet fired body 1Ba, 1Bb, 2Aa, 2Ab, 2Ba, 2Bb, 10Ba, 20Ba...Main surface 2...Phosphor layer 2A...Green sheet for phosphor layer formation 2B...Phosphor layer precursor 3...Glass matrix 4...Inorganic phosphor 10, 10B...First glass layer 10A...Green sheet for first glass layer formation 11, 21...Constraining green sheet 20, 20B...Second glass layer 20A...Green sheet for second glass layer formation 30...Light source 31, 41...Light-emitting device 42...Light guide plate A...Excitation light B...Fluorescence
Claims
1. A method for manufacturing a wavelength conversion member, comprising: a phosphor layer having a glass matrix and an inorganic phosphor dispersed in the glass matrix; a first glass layer provided on one main surface of the phosphor layer; and a second glass layer provided on the other main surface of the phosphor layer, the method comprising: a green sheet manufacturing step of producing a green sheet for forming a phosphor layer containing glass powder and inorganic phosphor particles, and a first green sheet for forming a glass layer and a second green sheet for forming a glass layer containing glass powder; a firing step of producing a green sheet laminate by laminating the first green sheet for forming a glass layer on one main surface of the phosphor layer green sheet and laminating the second green sheet for forming a glass layer on the other main surface of the phosphor layer green sheet, and firing the green sheet laminate to form a fired green sheet body; and a polishing step of polishing the main surfaces on both sides of the fired green sheet body to form a wavelength conversion member.
2. A method for manufacturing a wavelength conversion member, comprising: a phosphor layer having a glass matrix and an inorganic phosphor dispersed in the glass matrix; a first glass layer provided on one main surface of the phosphor layer; and a second glass layer provided on the other main surface of the phosphor layer, the method comprising: a green sheet manufacturing step of producing a first glass layer forming green sheet and a second glass layer forming green sheet containing glass powder; a firing step of producing a phosphor layer precursor containing glass powder and inorganic phosphor particles on one main surface of the first glass layer forming green sheet, and laminating the second glass layer forming green sheet on the main surface of the phosphor layer precursor opposite to the first glass layer forming green sheet to produce a green sheet laminate, and firing the green sheet laminate to form a fired green sheet body; and a polishing step of polishing the main surfaces on both sides of the fired green sheet body to form a wavelength conversion member.
3. The method for manufacturing a wavelength conversion member according to claim 2, wherein, in preparing the phosphor layer precursor, a phosphor layer precursor is prepared by applying a phosphor layer forming paste containing the glass powder and the inorganic phosphor particles onto one main surface of the first glass layer forming green sheet.
4. The method for manufacturing a wavelength conversion member according to any one of claims 1 to 3, wherein when forming the green sheet fired body, the green sheet fired body is formed to have a thickness greater than the target thickness of the wavelength conversion member, and in the polishing step, the main surfaces on both sides of the green sheet fired body are polished to the target thickness to obtain the wavelength conversion member.
5. The method for manufacturing a wavelength conversion member according to any one of claims 1 to 3, wherein in the polishing step, the main surfaces on both sides of the green sheet fired body are polished so that the thickness ratio (first glass layer / second glass layer) of the thickness of the first glass layer constituting the wavelength conversion member to the thickness of the second glass layer is 0.9 or more and 1.1 or less.
6. The method for manufacturing a wavelength conversion member according to any one of claims 1 to 3, wherein in the polishing step, the main surfaces on both sides of the green sheet fired body are polished so that the thickness ratio (glass layer / phosphor layer) of the thickness of the first glass layer and the second glass layer constituting the wavelength conversion member to the thickness of the phosphor layer is 0.3 or more and 5 or less.
7. The method for manufacturing a wavelength conversion member according to any one of claims 1 to 3, wherein in the polishing step, the main surfaces on both sides of the green sheet fired body are polished so as not to polish the phosphor layer constituting the wavelength conversion member.
8. A method for manufacturing a wavelength conversion member according to any one of claims 1 to 3, wherein the glass powder contained in the phosphor layer forming green sheet and the glass powder contained in the first glass layer forming green sheet and the second glass layer forming green sheet have the same glass composition.
9. A method for manufacturing a wavelength conversion member according to any one of claims 1 to 3, wherein the inorganic phosphor particles contained in the green sheet for forming the phosphor layer are composed of nitride phosphors or oxynitride phosphors.
10. A wavelength conversion member comprising: a phosphor layer having a glass matrix and an inorganic phosphor dispersed in the glass matrix; a first glass layer provided on one main surface of the phosphor layer; and a second glass layer provided on the other main surface of the phosphor layer, wherein the first glass layer and the second glass layer have polishing marks on their surfaces.
11. The wavelength conversion member according to claim 10, wherein the inorganic phosphor contained in the phosphor layer is a nitride phosphor or an oxynitride phosphor.
12. The wavelength conversion member according to claim 10 or 11, wherein the content of the inorganic phosphor in the phosphor layer is 5% by volume or more and 74% by volume or less.
13. A light-emitting device comprising: a wavelength conversion member according to claim 10 or 11; and a light source that emits excitation light to the wavelength conversion member.