Method for manufacturing phosphor substrate and method for manufacturing light-emitting substrate

Abstract

This method for manufacturing a phosphor substrate (30) on which at least one light emitting element (20) is mounted comprises: a circuit pattern layer forming step for forming, on one surface of an insulating layer (31), a circuit pattern layer (34) joined to the at least one light emitting element (20); a phosphor layer forming step for forming, on one surface side of the insulating layer (31), a phosphor layer (36) containing a phosphor the emission peak wavelength of which is in the visible light region when using the light emitted by the at least one light emitting element (20) as the excitation light; and a support layer forming step for forming, between the insulating layer (31) and the phosphor layer (36), a support layer (35) that does not contain a phosphor and that supports the phosphor layer (36), wherein, in the support layer forming step, the support layer (35) is laminated on the circuit pattern layer (34) in a region provided with the circuit pattern layer (34).

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a phosphor substrate and a method for manufacturing a light-emitting substrate. [Background technology]

[0002] Patent Document 1 discloses an LED lighting device that includes a substrate on which a light-emitting element (LED element) is mounted. This LED lighting device has a reflective material on the surface of the substrate to improve light-emitting efficiency. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Chinese Patent Publication No. 106163113 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration disclosed in Patent Document 1, it is not possible to use a reflector to adjust the light emitted by the LED lighting fixture to light of a different color from the light emitted by the light emitting element.

[0005] The present invention aims to provide a technology for a phosphor substrate that can reduce the glare of light emitted by a light-emitting element when the light-emitting element is mounted thereon, and can efficiently achieve the function of adjusting the light emitted by the light-emitting element to a different color. [Means for solving the problem]

[0006] The present invention provides the following techniques. [1] A method for manufacturing a phosphor substrate on which at least one light-emitting element is mounted, comprising: a circuit pattern layer forming step of forming a circuit pattern layer bonded to the at least one light emitting element on one surface of an insulating substrate; a phosphor layer forming step of forming a phosphor layer on one surface of the insulating substrate, the phosphor layer including a phosphor having an emission peak wavelength in a visible light region when the emission of the at least one light-emitting element is used as excitation light; a support layer forming step of forming a support layer between the insulating substrate and the phosphor layer, the support layer not containing the phosphor and supporting the phosphor layer; Including, In the support layer forming step, the support layer is laminated on the circuit pattern layer in the region where the circuit pattern layer is provided. [2] The method for manufacturing a phosphor substrate according to [1], wherein, when the light-emitting element is an LED, the phosphor layer forming step forms the phosphor layer so that the position of the PN junction region of the LED closest to the insulating substrate is within the range of the phosphor layer in the thickness direction. [3] The method for producing a phosphor substrate according to [1] or [2], wherein the support layer forming step forms a layer having a single layer structure containing a white pigment as the support layer. [4] The method for producing a phosphor substrate according to any one of [1] to [3], wherein the phosphor layer forming step does not form the phosphor layer in an area where the light emitting element is to be mounted. [5] The method for manufacturing a phosphor substrate according to [4], wherein the phosphor layer forming step does not form the phosphor layer around the area where the light-emitting element is mounted, and instead forms a support layer exposed portion where the support layer is exposed. [6] The method for producing a phosphor substrate according to [5], wherein the distance from the phosphor layer to the light emitting element in the exposed support layer portion is 50 μm to 200 μm. [7] The method for producing a phosphor substrate according to [5] or [6], further comprising a support layer recess forming step of forming a support layer recess having a concave shape in the thickness direction in the exposed portion of the support layer. [8] The phosphor is composed of a plurality of phosphor particles, the white pigment contained in the support layer is composed of a plurality of white particles, The volume-based median diameter (D 50 )D1 50 and a volume-based median diameter (D 50 )D2 50 The method for producing a phosphor substrate according to any one of [1] to [7], which satisfies the relationship of the following formula 2: (Formula 2)0.8≦D2 50 / D1 50 ≦1.2 [9] In the support layer forming step, the support layer is formed on one surface of the insulating substrate while a discharge unit that discharges the liquid that does not contain the phosphor is moved relative to the insulating substrate; The method for manufacturing a phosphor substrate according to any one of [1] to [8], wherein in the phosphor layer forming step, the phosphor layer is laminated on the support layer while moving an ejection unit that ejects a liquid containing the phosphor relative to the support layer.

[10] In the support layer forming step, the support layer is formed on one surface of the insulating substrate by printing; The method for producing a phosphor substrate according to any one of [1] to [8], wherein in the phosphor layer forming step, the phosphor layer is laminated by printing on the circuit pattern layer.

[11] A method for producing a phosphor substrate according to any one of [1] to

[10] ; a bonding step of bonding the at least one light emitting element to the circuit pattern layer; A method for manufacturing a light-emitting substrate, comprising:

[12] The method for manufacturing a light-emitting substrate according to

[11] , wherein the bonding step is performed after the phosphor layer forming step. [Effects of the Invention]

[0007] According to the present invention, a technology for a phosphor substrate can be provided that can reduce the glare of light emitted by a light-emitting element when the light-emitting element is mounted, and can efficiently achieve the function of adjusting the light emitted by the light-emitting element to a different color. [Brief explanation of the drawings]

[0008] [Figure 1A] FIG. 2 is a plan view of the light emitting substrate of the first embodiment. [Figure 1B] FIG. 2 is a bottom view of the light emitting substrate of the first embodiment. [Figure 1C] 1C is a partial cross-sectional view of the light-emitting substrate taken along the line 1C-1C in FIG. 1A. [Figure 1D] 1B is an enlarged plan view of region A1 in FIG. 1A showing the vicinity of a region where one light emitting element is mounted. [Figure 2A] 1 is a plan view of a phosphor substrate (phosphor layer and support layer are omitted) of a first embodiment. [Figure 2B] FIG. 2 is a plan view of the phosphor substrate of the first embodiment. [Figure 3A] 3A to 3C are explanatory views of a first step in the method for manufacturing the light emitting substrate of the first embodiment. [Figure 3B] 5A to 5C are explanatory views of a second step in the method for manufacturing the light emitting substrate of the first embodiment. [Figure 3C] 5A to 5C are explanatory views of a third step in the method for manufacturing the light emitting substrate of the first embodiment. [Figure 3D] 5A to 5C are explanatory views of a fourth step in the method for manufacturing the light emitting substrate of the first embodiment. [Figure 3E] 5A to 5C are explanatory views of a fifth step in the method for manufacturing the light emitting substrate of the first embodiment. [Figure 4] 5A to 5C are diagrams for explaining the light emitting operation of the light emitting substrate of the first embodiment. [Figure 5] 10A and 10B are diagrams for explaining the light emitting operation of a light emitting substrate of a comparative example. [Figure 6] FIG. 10 is a partial cross-sectional view of a light emitting substrate according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Overview First to fifth embodiments of the present invention will be described in this order. Next, modified examples of these embodiments will be described. In all drawings referred to in the following description, like components will be designated by like reference numerals, and their description will be omitted where appropriate.

[0010] First Embodiment The first embodiment will be described below with reference to Figures 1A to 5. First, the configuration and function of the light emitting substrate 10 of this embodiment will be described with reference to Figures 1A to 1D. Next, a method for manufacturing the light emitting substrate 10 of this embodiment will be described with reference to Figures 3A to 3E. Next, the light emitting operation of the light emitting substrate 10 of this embodiment will be described with reference to Figure 4. Next, the effects of this embodiment will be described with reference to Figures 4, 5, etc.

[0011] <Configuration and Function of Light-Emitting Substrate of First Embodiment> FIG. 1A is a plan view of the light emitting substrate 10, and FIG. 1B is a bottom view of the light emitting substrate 10. FIG. 1C is a partial cross-sectional view of the light emitting substrate 10 taken along the 1C-1C cutting line in FIG. 1A. FIG. 1D is an enlarged view of region C2 in FIG. 1A, focusing on one light emitting element 20. Note that the plan view is a view seen from, for example, the front surface 32 side of the insulating layer 31 described below, and the bottom view is a view seen from the back surface 33 side of the insulating layer 31. In the following embodiments, the "front surface 32 side" will be described as the "+Z direction side," and the "back surface 33 side" will be described as the "-Z direction side."

[0012] As shown in the plan view and bottom view, the light emitting substrate 10 is, for example, rectangular when viewed from the "+Z direction side" and the "-Z direction side." The light emitting substrate 10 of this embodiment includes a plurality of light emitting elements 20, a phosphor substrate 30, and electronic components (not shown) such as a connector and a driver IC. The light emitting substrate 10 has the function of emitting light when power is supplied from an external power source (not shown) via the connector. Therefore, the light emitting substrate 10 is used as a main optical component in, for example, a lighting device (not shown).

[0013] Although detailed in the following description, the basic configurations of the phosphor substrate 30 and the light emitting substrate 10 of this embodiment are as follows.

[0014] <Basic structure of phosphor substrate> The phosphor substrate 30 is mounted with at least one light emitting element 20. Specifically, the phosphor substrate 30 includes an insulating layer 31 (an example of an insulating substrate), a circuit pattern layer 34, a support layer 35, and a phosphor layer 36.

[0015] The circuit pattern layer 34 is disposed on the surface 32 (an example of one surface) of the insulating layer 31, and is bonded to at least one light-emitting element 20. The phosphor layer 36 is disposed on the surface 32 side of the insulating layer 31, and contains a phosphor whose emission peak wavelength is in the visible light region when the emission of at least one light-emitting element 20 is used as excitation light. The support layer 35 is disposed on the surface 32 of the insulating layer 31, and in the region where the circuit pattern layer 34 is provided on the insulating layer 31, the support layer 35 is disposed on the surface of the circuit pattern layer 34 to support the phosphor layer 36. The support layer 35 is provided as a layer that does not contain a phosphor.

[0016] <Basic structure of the light-emitting substrate> The light emitting substrate 10 includes a phosphor substrate 30 having the basic configuration described above and at least one light emitting element 20.

[0017] [Multiple Light-Emitting Elements] Each of the light-emitting elements 20 is, for example, a CSP (Chip Scale Package) incorporating a flip-chip LED 22 (hereinafter referred to as "LED 22") (see FIGS. 1C and 1D). The LED 22 is square in top view (i.e., when viewed from the +Z direction), and the length L1 of one side is, for example, 1200 μm or 1700 μm.

[0018] 1A, the plurality of light-emitting elements 20 are mounted in a regular arrangement over the entire surface side of the phosphor substrate 30. The correlated color temperature of the light emitted by each light-emitting element 20 is, for example, 3,018 K. Note that by using a heat sink (not shown) and a cooling fan (not shown), the phosphor substrate 30 is configured to dissipate heat (cool) so that, when the plurality of light-emitting elements 20 are operating to emit light, the temperature is kept within, for example, a room temperature of 50°C to 100°C.

[0019] Here, to clarify the meaning of "to" used in numerical ranges in this specification, for example, "50°C to 100°C" means "50°C or higher and 100°C or lower." In other words, when "to" is used in a numerical range in this specification, it means "not lower than the value before "to" and not higher than the value after "to."

[0020] [Phosphor substrate] FIG. 2A is a plan view of the phosphor substrate 30, omitting the support layer 35 and the phosphor layer 36. FIG. 2B is a plan view of the phosphor substrate 30. Note that the bottom view of the phosphor substrate 30 of this embodiment is the same as the view of the light-emitting substrate 10 seen from the back surface side (-Z direction side). Also, the partial cross-sectional view of the phosphor substrate 30 is the same as the view of the partial cross-sectional view of FIG. 1C with the light-emitting element 20 removed. That is, the phosphor substrate 30 is, for example, rectangular when viewed from the +Z direction side and the -Z direction side.

[0021] 2A illustrates the range of the plurality of electrode pairs 34A, which will be described later, and the wiring portion 34B, which is the portion other than the plurality of electrode pairs 34A, but in reality, since both are formed on the same plane (outer surface), there is no boundary between them in a view excluding the support layer 35 and the phosphor layer 36, as in Fig. 2A. However, for the sake of convenience, Fig. 2A includes the reference numerals for the plurality of electrode pairs 34A and the wiring portion 34B in order to clarify the positional relationship between them.

[0022] The phosphor substrate 30 includes an insulating layer 31, a circuit pattern layer 34, a support layer 35, a phosphor layer 36, and a back surface pattern layer 38 (see FIGS. 1B to 1D, 2A, and 2B). The support layer 35 and the phosphor layer 36 are omitted in FIG. 2A.

[0023] 1C, for example, the phosphor layer 36 is disposed on the surface of the support layer 35 on the +Z direction side (i.e., the outer surface 35x). However, the phosphor layer 36 is not provided in the region where the light emitting element 20 is provided. Furthermore, the phosphor layer 36 is not provided in a region of a certain width (predetermined distance L2) from the region where the light emitting element 20 is provided, and a support layer exposed portion 70 where the support layer 35 is exposed is formed.

[0024] The width of the exposed support layer portion 70, i.e., the predetermined distance L2, is preferably set to, for example, 50 μm to 200 μm. If the predetermined distance L2 is less than 50 μm, manufacturing errors or the viscosity of the phosphor paint may cause the phosphor layer 36 to flow toward the light emitting element 20 when it is formed, resulting in adhesion to the optical element mounting area 75 (see FIGS. 3C and 3D), which is the mounting surface of the light emitting element 20, preventing proper mounting. If the predetermined distance L2 is 200 μm or more, the light output from the light emitting element 20 may not sufficiently reach the phosphor layer 36, which may reduce the efficiency of the phosphor substrate 30's function (i.e., its color temperature shifting function).

[0025] 1B and 2A, the phosphor substrate 30 has through holes 39 formed in six locations: four near the four corners and two near the center. The six through holes 39 are used as positioning holes during the manufacture of the phosphor substrate 30 and the light-emitting substrate 10. The six through holes 39 are also used as screw holes for mounting to ensure heat dissipation to the (light-emitting) lamp housing (preventing warping and lifting of the substrate). As will be described later, the phosphor substrate 30 of this embodiment is manufactured by etching or other processing a double-sided board (hereinafter referred to as a motherboard MB; see FIG. 3A) in which copper foil layers are provided on both sides of an insulating plate. An example of the motherboard MB used is the CS-3305A manufactured by Risho Kogyo Co., Ltd.

[0026] <Insulating layer> The main features of the insulating layer 31 of this embodiment will be described below. As described above, the shape is, for example, rectangular when viewed from the front surface 32 side (+Z direction side) and the back surface 33 side (-Z direction side). The material is, for example, an insulating material containing bismaleimide resin and glass cloth. The thickness T1 is, for example, 100 μm. The coefficients of thermal expansion (CTE) in the vertical and horizontal directions are, for example, 10 ppm / °C or less in the temperature range of 50°C to 100°C. From another perspective, the coefficients of thermal expansion (CTE) in the vertical and horizontal directions are, for example, 6 ppm / K. This value is almost the same as that of the light emitting device 20 of this embodiment (90% to 110%, i.e., within ±10%). The glass transition temperature is, for example, greater than 300°C. For example, the storage modulus is 1.0 × 10 in the range of 100 °C to 300 °C. 10 Pa greater than 1.0 × 10 11 Smaller than Pa. The bending moduli in the machine direction and the cross direction are, for example, 35 GPa and 34 GPa, respectively, in the normal state. The hot bending modulus in the longitudinal and transverse directions is, for example, 19 GPa at 250°C. The water absorption is, for example, 0.13% when left in a 23°C temperature environment for 24 hours. The relative permittivity is, for example, 4.6 at 1 MHz normal state. The dielectric loss tangent is, for example, 0.010 at 1 MHz normal state.

[0027] <Circuit pattern layer> The circuit pattern layer 34 is a metal layer provided on the surface 32 side (+Z direction side) of the insulating layer 31, and is, for example, a copper foil layer (a layer made of Cu), and is electrically connected to a terminal 37 joined to a connector (not shown). The circuit pattern layer 34 supplies power supplied from an external power source (not shown) via the connector to the plurality of light-emitting elements 20 in a state where it constitutes the light-emitting substrate 10. Therefore, a portion of the circuit pattern layer 34 serves as a plurality of electrode pairs 34A to which the plurality of light-emitting elements 20 are respectively joined. That is, the circuit pattern layer 34 is disposed on the surface 32 of the insulating layer 31, and is connected to each light-emitting element 20 at a joining surface 34A1, which is the outer surface of each electrode pair 34A.

[0028] As described above, the plurality of light-emitting elements 20 are regularly arranged over the entire surface 32 of the insulating layer 31 (see FIG. 1A), and therefore the plurality of electrode pairs 34A are also regularly arranged over the entire surface 32 (see FIG. 2A). Here, the portion of the circuit pattern layer 34 other than the plurality of electrode pairs 34A is referred to as a wiring portion 34B. The outer surface of the wiring portion 34B (i.e., the portion of the outer surface of the circuit pattern layer 34 other than the bonding surface 34A1) is referred to as a non-bonding surface 34B1. The non-bonding surface 34B1 is the portion of the circuit pattern layer 34 other than the portion bonded to all of the light-emitting elements 20.

[0029] The area on the surface 32 of the insulating layer 31 where the circuit pattern layer 34 is disposed (the area occupied by the circuit pattern layer 34) is, for example, 60% or more of the area of ​​the surface 32 of the insulating layer 31 (see FIG. 2A). The thickness T3 of the circuit pattern layer 34 is, for example, 175 μm. However, in each figure, the relationship between the thickness T3 of the circuit pattern layer 34, the thickness T1 of the insulating layer 31, the thickness T5 of the phosphor layer 36, etc. is not dimensionally represented.

[0030] <Support layer> The support layer 35 is provided on the surface 32 of the insulating layer 31, or on the circuit pattern layer 34 in the region where the circuit pattern layer 34 is provided, and supports the phosphor layer 36. However, the phosphor layer 36 is not provided in the region where the solder paste SP is provided. Furthermore, in the region of the circuit pattern layer 34 between the pair of electrodes 34A where the circuit pattern layer 34 has been removed to form the recess 34x, a recess support layer 35b is provided to fill the recess 34x.

[0031] 1C, 3E, and the like, the thickness T4 of the support layer 35 in the region provided on the circuit pattern layer 34 is set to be thinner than the thickness T3 of the circuit pattern layer 34, more specifically, 20 μm, for example. The support layer 35 in the region where the circuit pattern layer 34 is not provided is set to have the same thickness (i.e., thickness T3+T4) as the outermost surface of the support layer 35 in the region provided on the circuit pattern layer 34, at the outermost surface position where the support layer 35 is provided. In other words, the support layer 35 is provided so as to be roughly flush with the entire phosphor substrate 30. The thickness T3 of the support layer 35 may be thinner, thicker, or the same as the thickness T3 of the circuit pattern layer 34 as described above, and can be set appropriately according to the required specifications.

[0032] Unlike the phosphor layer 36 described later, the support layer 35 does not contain phosphor (an aggregate of multiple phosphor particles), but contains a white pigment (an aggregate of multiple white particles) and a binder, and is an insulating layer in which multiple white particles are dispersed in the binder.

[0033] The support layer 35 has a single layer structure, for example. Here, the plurality of white particles are, for example, titanium oxide, but may be calcium oxide or other white particles. The binder may be, for example, an epoxy-based, acrylate-based, or silicone-based binder, as long as it has insulating properties equivalent to those of the binder contained in the solder resist.

[0034] The technical significance of the support layer 35 containing a white pigment will be explained later in the description of the effects of the first embodiment.

[0035] <Phosphor layer> 1C, 2B, and 3E, the phosphor layer 36 is provided, for example, on the surface (outer surface 35x) of the support layer 35 opposite to the surface in contact with the insulating layer 31. The area on the surface 32 of the insulating layer 31 where the phosphor layer 36 is arranged is, for example, 80% or more of the area of ​​the surface 32 of the insulating layer 31.

[0036] The surface of the phosphor layer 36 on the lower side in the thickness direction (-Z direction side), i.e., the boundary with the outer surface 35x of the support layer 35, is set lower than the position of the junction 25 of the LED 22 (see FIGS. 1C and 3E). In other words, the mounting level of the light emitting element 20, which is a CSP, is the same as the lower surface level of the phosphor layer 36. Here, the junction 25 of the LED 22 refers to the PN junction region of the LED 22, and light is emitted at this junction 25.

[0037] The phosphor layer 36 is, for example, an insulating layer containing a phosphor (an aggregate of a plurality of phosphor particles) and a binder, which will be described later, with the plurality of phosphor particles dispersed in the binder. The phosphor contained in the phosphor layer 36 has the property of being excited by the light emitted from each light-emitting element 20. Specifically, the phosphor of this embodiment has the property of having an emission peak wavelength in the visible light region when the light emitted from the light-emitting element 20 is used as excitation light. The binder may be, for example, an epoxy-based, acrylate-based, or silicone-based binder, as long as it has insulating properties equivalent to those of the binder contained in the solder resist.

[0038] Here, in this specification, the volume-based median diameter (D 50 ) to D1 50 In addition, the volume-based median diameter (D 50 ) to D2 50 In this case, in the phosphor substrate 30 of this embodiment, D150 and D2 50 and have the following relationship (Equation 1). (Formula 1)0.8≦D2 50 / D1 50 ≦1.2 That is, in this embodiment, the median diameter (D 50 ) is the median diameter (D 50 ) is set to be in the range of 80% to 120%.

[0039] (Specific examples of phosphors) Here, the phosphor contained in the phosphor layer 36 of this embodiment is, for example, at least one phosphor selected from the group consisting of an α-sialon phosphor containing Eu, a β-sialon phosphor containing Eu, a CASN phosphor containing Eu, and a SCASN phosphor containing Eu. Note that the above-mentioned phosphor is an example in this embodiment, and a phosphor other than the above-mentioned phosphors may also be used, such as YAG, LuAG, BOS, or other visible light-excited phosphors.

[0040] The α-type SiAlON phosphor containing Eu has the general formula: M x EU y Si 12-(m+n) Al (m+n) O n N 16-n In the above general formula, M is one or more elements selected from the group consisting of Li, Mg, Ca, Y, and lanthanide elements (excluding La and Ce), including at least Ca, and when the valence of M is a, ax+2y=m, and x is 0. <x≦1.5であり、0.3≦m<4.5、0<n<2.25である。

[0041] The β-type sialon phosphor containing Eu has the general formula: Si 6-z Al z O z N 8-z The β-SiAlON (z=0.005-1) is treated with divalent europium (Eu 2+ ) is a solid solution phosphor.

[0042] Furthermore, examples of nitride phosphors include CASN phosphors containing Eu and SCASN phosphors containing Eu.

[0043] CASN phosphors containing Eu can be, for example, of the formula CaAlSiN3:Eu 2+ It is expressed as Eu 2+ This refers to a red phosphor that uses as an activator an alkaline earth silicon nitride crystal as a matrix. Note that the definition of Eu-containing CASN phosphor in this specification excludes Eu-containing SCASN phosphor.

[0044] The Eu-containing SCASN phosphor is, for example, of the formula (Sr,Ca)AlSiN3:Eu 2+ It is expressed as Eu 2+ This refers to a red phosphor that uses as an activator an alkaline earth silicon nitride crystal as a matrix.

[0045] <Back pattern layer> The rear pattern layer 38 is a metal layer provided on the rear surface 33 side of the insulating layer 31, and is, for example, a copper foil layer (a layer made of Cu). The thickness T2 of the rear pattern layer 38 is, for example, 175 μm. 1B, the rear surface pattern layer 38 is a layer in which a plurality of rectangular blocks are arranged linearly along the longitudinal direction of the insulating layer 31 and are arranged adjacent to each other so as to be out of phase with each other in the short direction. In addition, the rear surface pattern layer 38 is, for example, an independent floating layer. The rear surface pattern layer 38 overlaps with 80% or more of the area of ​​the circuit pattern layer 34 disposed on the front surface 32 of the insulating layer 31 in the thickness direction, for example.

[0046] The above is a description of the configurations of the light emitting substrate 10 and the phosphor substrate 30 of this embodiment.

[0047] <Method for manufacturing the light emitting substrate of the first embodiment> Next, a method for manufacturing the light emitting substrate 10 of this embodiment will be described with reference to Figures 3A to 3E. The method for manufacturing the light emitting substrate 10 of this embodiment includes a first step, a second step, a third step, a fourth step, and a fifth step, and each step is performed in the order described.

[0048] Although detailed below, the basic configurations of the method for manufacturing the phosphor substrate 30 and the method for manufacturing the light emitting substrate 10 of this embodiment are as follows.

[0049] Basic structure of phosphor substrate manufacturing method The manufacturing method of the phosphor substrate 30 of this embodiment includes a first step (circuit pattern layer formation step) of forming a circuit pattern layer 34 to be bonded to at least one light-emitting element 20 on the surface 32 (an example of one surface) of an insulating layer 31 (an example of an insulating substrate); a third step (phosphor layer formation step) of forming a phosphor layer 36 on the surface 32 side of the insulating layer 31, the phosphor layer 36 containing a phosphor whose emission peak wavelength when the emission of at least one light-emitting element 20 is used as excitation light, is in the visible light region; and a second step (support layer formation step) of forming a support layer 35 between the insulating layer 31 and the phosphor layer 36, the support layer 35 being a layer that does not contain the phosphor and supports the phosphor layer 36. In the phosphor layer formation step, the phosphor layer 36 is stacked on the support layer 35 by a screen printing technique, excluding the area where the light-emitting element 20 is mounted from the stacking area.

[0050] Basic structure of the manufacturing method for light-emitting substrates The method for manufacturing the light emitting substrate 10 of this embodiment includes the method for manufacturing the phosphor substrate 30 of this embodiment described above, and a fifth step (bonding step) of bonding at least one light emitting element 20 to the circuit pattern layer 34.

[0051] [1st process] 3A is a diagram showing the start and end of the first step. The first step (an example of a circuit pattern layer forming step) is a step of forming a circuit pattern layer 34 on the front surface 32 of the insulating layer 31 of the motherboard MB and a back surface pattern layer 38 on the back surface 33. This step is performed by etching using, for example, a mask pattern (not shown).

[0052] [Second process] 3B is a diagram showing the start and end of step 2. Step 2 (an example of a support layer forming step) is a step of forming support layer 35, which is a layer that does not contain phosphor and supports phosphor layer 36 formed in step 3, between insulating layer 31 and phosphor layer 36 formed in step 3.

[0053] In this process, a white paint (not shown) is applied to the surface of the circuit pattern layer 34 in the area on the surface 32 of the insulating layer 31 where the circuit pattern layer 34 is arranged, and to the surface of the insulating layer 31 in the area where the circuit pattern layer 34 is not arranged, to form a support layer 35.

[0054] The white paint is a paint made by adding a solvent to the white pigment (an aggregate of multiple white particles) and binder that make up the support layer 35, and the applied layer of white paint becomes the support layer 35 after hardening. As a result, when this process is completed, a layer with a single layer structure containing the white pigment is formed as the support layer 35.

[0055] The support layer 35 formed in this step may be formed by applying the white paint in the thickness direction of the insulating layer 31 in one application or multiple applications.

[0056] [3rd step] 3C is a diagram showing the start and end of the third step. The third step (an example of a phosphor layer forming step) is a step of applying a phosphor paint (not shown) to the outer surface 35x of the support layer 35 to form the phosphor layer 36. Specifically, in this step, the phosphor paint is applied by screen printing to the outer surface 35x of the support layer 35 formed in the second step, excluding the optical element mounting region 75 (i.e., the CSP mounting region) where the light emitting element 20 is mounted and the support layer exposed portion 70 provided therearound. In this step, the phosphor layer 36 is formed on the outer surface 35x of the support layer 35, and is formed so that the outer surface 36x of the phosphor layer 36 is flat.

[0057] [4th step] 3D shows the start and end of the fourth step. The fourth step is a step of removing a portion of the support layer 35 to expose all of the bonding surfaces 34A1 of the circuit pattern layer 34. After the support layer 35 is hardened by heating, a two-dimensional laser processing device (not shown) is used to selectively irradiate the support layer 35 with laser light onto the portions of the support layer 35 on the bonding surfaces 34A1. As a result, the portions of the support layer 35 on the bonding surfaces 34A1 are ablated, exposing the bonding surfaces 34A1. In addition to the removal method using laser light irradiation, the bonding surfaces 34A1 may be exposed in advance in the second step (support layer formation step) using a technique such as photoprinting or screen printing. When this step is completed, the phosphor substrate 30 is manufactured.

[0058] [5th ​​process] FIG. 3E is a diagram showing the start and end of the fifth step. The fifth step (an example of a bonding step) is a step of mounting a plurality of light-emitting elements 20 on the phosphor substrate 30. In this step, solder paste SP is printed on each bonding surface 34A1 exposed by removing a recess in the support layer 35 of the phosphor substrate 30, and the solder paste is melted while the electrodes of the plurality of light-emitting elements 20 are aligned with each bonding surface 34A1. Thereafter, when the solder paste SP cools and solidifies, each light-emitting element 20 is bonded to each electrode pair 34A (each bonding surface 34A1). Note that this step is performed by a reflow process, for example. When this step is completed, the light emitting substrate 10 is manufactured.

[0059] <Light Emitting Operation of the Light Emitting Substrate of the First Embodiment> Next, the light-emitting operation of the light-emitting substrate 10 of this embodiment will be described with reference to Fig. 4. Fig. 4 is a diagram for explaining the light-emitting operation of the light-emitting substrate 10 of this embodiment, focusing on the phosphor layer 36 and omitting the support layer 35. The same is true for Fig. 5, which shows a light-emitting substrate 10a of a comparative embodiment, which will be described later.

[0060] First, when an activation switch (not shown) that activates the plurality of light-emitting elements 20 is turned on, power supply from an external power source (not shown) to the circuit pattern layer 34 begins via a connector (not shown), and the plurality of light-emitting elements 20 emit radially divergent light L, and part of the light L reaches the surface of the phosphor substrate 30 (i.e., the outer surface 36x of the phosphor layer 36). Below, the behavior of the emitted light L will be explained according to the traveling direction of the light L.

[0061] A portion of the light L emitted from each light-emitting element 20 is reflected by the outer surface 36x and emitted to the outside without entering the phosphor layer 36. In this case, the wavelength of the light L remains the same as the wavelength of the light L when it was emitted from each light-emitting element 20.

[0062] Furthermore, the light of the LED 22 itself among the portion of the light L emitted from each light-emitting element 20 is incident on the phosphor layer 36. Here, the aforementioned "light of the LED 22 itself among the portion of the light L" means the light of the emitted light L that has not been color-converted by the phosphor of each light-emitting element 20 (CSP itself), i.e., the light of the LED 22 itself (for example, blue light (with a wavelength of around 470 nm)).

[0063] When the light L from the LED 22 itself collides with the phosphors dispersed in the phosphor layer 36, the phosphors are excited and emit excited light. The phosphors are excited because the phosphors dispersed in the phosphor layer 36 are phosphors (visible light excited phosphors) that have an excitation peak in blue light. As a result, part of the energy of the light L is used to excite the phosphors, and the light L loses part of its energy. As a result, the wavelength of the light L is converted (wavelength conversion is performed). For example, depending on the type of phosphor in the phosphor layer 36 (for example, when a red CASN is used as the phosphor), the wavelength of the light L becomes longer (for example, 650 nm).

[0064] Furthermore, some of the excitation light in the phosphor layer 36 is emitted directly from the phosphor layer 36, but a portion of the excitation light travels toward the underlying support layer 35. The excitation light that travels toward the support layer 35 is reflected by the support layer 35 and emitted to the outside. When the support layer 35 is made of a white pigment as described above, the reflection effect can be improved over the entire wavelength range of visible light.

[0065] As described above, the light L emitted from each light-emitting element 20 (the light L radially emitted from each light-emitting element 20) travels through the multiple optical paths described above and is irradiated to the outside together with the excitation light. Therefore, when the emission wavelength of the phosphor contained in the phosphor layer 36 differs from the emission wavelength of the phosphor that encapsulates (or covers) the LED 22 in the light-emitting element 20 (CSP), the light-emitting substrate 10 of this embodiment irradiates a flux of light L emitted from each light-emitting element 20 together with the excitation light as a flux of light L containing light L of a wavelength different from the wavelength of the light L emitted from each light-emitting element 20. For example, the light-emitting substrate 10 of this embodiment irradiates a composite light of the light (wavelength) emitted from the light-emitting element 20 and the light (wavelength) emitted from the phosphor layer 36.

[0066] In contrast, when the emission wavelength of the phosphor contained in the phosphor layer 36 is the same as the emission wavelength of the phosphor that encapsulates (or covers) the LED 22 in the light-emitting element 20 (CSP) (when the correlated color temperature is the same), the light-emitting substrate 10 of this embodiment irradiates the flux of light L emitted by each light-emitting element 20 as a flux of light L containing light L of the same wavelength as the wavelength of the light L emitted by each light-emitting element 20 together with the above-mentioned excitation light.

[0067] If the junction 25 constituting the CSP light-emitting element 20 is located below (on the -Z direction side of) the phosphor layer 36, the light-emitting efficiency of the phosphor substrate 30 will decrease. That is, the light emitted by the LED 22 itself will not reach the phosphor layer 36, and the color temperature shift of the phosphor substrate 30 will be smaller than that of the CSP. Considering the above function, the relationship between the junction 25 and the phosphor layer 36 is particularly important in the area near the light-emitting element 20. In other words, it is not necessary to satisfy this relationship in areas where the light from the light-emitting element 20 does not reach, such as the peripheral portion of the light-emitting substrate 10. The above is a description of the light emitting operation of the light emitting substrate 10 of this embodiment.

[0068] <Effects of the first embodiment> Next, the effects of this embodiment will be summarized with reference to the drawings.

[0069] [First effect] The first effect will be explained by comparing this embodiment with a comparative embodiment (see FIG. 5) described below. Here, in explaining the comparative embodiment, when the same components as those of this embodiment are used, the same names, symbols, etc. as those of this embodiment will be used for those components. FIG. 5 is a diagram for explaining the light-emitting operation of the light-emitting substrate 10a of the comparative embodiment. The light-emitting substrate 10a of the comparative embodiment (substrate 30a on which a plurality of light-emitting elements 20 are mounted) has the same configuration as the light-emitting substrate 10 (phosphor substrate 30) of this embodiment, except that it does not have the phosphor layer 36.

[0070] In the case of the light emitting substrate 10a of the comparative embodiment, the light L emitted from each light emitting element 20 and incident on the surface 32 of the substrate 30a is reflected or scattered without being converted in wavelength. Therefore, in the case of the substrate 30a of the comparative embodiment, when the light emitting elements 20 are mounted, it is not possible to adjust the emitted light color to a different color from the light emitted by the light emitting elements 20. In other words, in the case of the light emitting substrate 10a of the comparative embodiment, it is not possible to adjust the emitted light color to a different color from the light emitted by the light emitting elements 20.

[0071] In contrast, in the present embodiment, a phosphor layer 36 is disposed on the surface of the light emitting substrate 10 (support layer surface 35X of the support layer 35 in FIG. 1C ) around each light emitting element 20 when viewed from the thickness direction of the insulating layer 31. Therefore, part of the light L radially emitted from each light emitting element 20 enters the phosphor layer 36, undergoes wavelength conversion by the phosphor layer 36, and is irradiated to the outside. In this case, part of the light L radially emitted from each light emitting element 20 enters the phosphor layer 36, excites the phosphor contained in the phosphor layer 36, and generates excitation light.

[0072] Therefore, according to the phosphor substrate 30 of the present embodiment, when the light emitting element 20 is mounted, it is possible to adjust the light L emitted from the phosphor substrate 30 to light of an emission color different from that of the light L emitted by the light emitting element 20. Accordingly, according to the light emitting substrate 10 of the present embodiment, it is possible to adjust the light L emitted from the phosphor substrate 30 to light L of an emission color different from that of the light L emitted by the light emitting element 20. From another perspective, according to the light emitting substrate 10 of the present embodiment, it is possible to irradiate light L of an emission color different from that of the light L emitted by the light emitting element 20 to the outside.

[0073] [Second effect] The second effect will be described by comparing this embodiment with a comparative example (see FIG. 5). In the comparative example, as shown in FIG. 5, mottling occurs in the light L irradiated to the outside due to the arrangement intervals of the light emitting elements 20. Here, it is said that the larger the mottling of the light L, the greater the glare. In contrast, as shown in Figures 1C, 1D, and 2BC, the surface of the phosphor substrate 30 of this embodiment is entirely covered with a phosphor layer 36, except for the optical element mounting region 75 and the support layer exposed portion 70 in the vicinity thereof. Therefore, in the light-emitting substrate 10 of this embodiment, excitation light is also emitted from the periphery of each light-emitting element 20. Therefore, according to this embodiment, glare can be reduced compared to the comparative embodiment. This effect is more pronounced when the phosphor layer 36 is provided over the entire surface of the light-emitting substrate 10, specifically, when the area in which the phosphor layer 36 is disposed occupies 80% or more of the surface 32 of the insulating layer 31.

[0074] [Third effect] In this embodiment, the light-emitting element 20 is a CSP, and the position of the PN junction region (i.e., junction 25) of the LED 22 constituting the CSP closest to the insulating layer 31 (the -Z direction side) is within the thickness direction of the phosphor layer 36. In other words, the mounting level of the CSP (LED 22) is the lower position in the stacking order of the phosphor layer 36 (the boundary level between the phosphor layer 36 and the support layer 35). Therefore, the light of the LED 22 output from the junction 25 reliably reaches the phosphor layer 36, and the function of the phosphor layer 36 can be efficiently realized.

[0075] [Fourth Effect] In this embodiment, the phosphor layer 36 is supported by the support layer 35 (see FIGS. 1C and 3E). More specifically, the entire region of the phosphor layer 36 is supported by the support layer 35, which has a single-layer structure containing a white pigment. Therefore, the reflection effect of the entire wavelength region of the excitation light, which is considered to be visible light, can be improved over the entire region of the phosphor layer 36.

[0076] Here, the white pigment constituting the support layer 35 is cheaper than the phosphor constituting the phosphor layer 36, and therefore the white paint for forming the support layer 35 is cheaper than the phosphor paint. Therefore, the phosphor substrate 30 of this embodiment is cheaper than when the support layer 35 is formed of the phosphor layer 36. Accordingly, the manufacturing method of the phosphor substrate 30 of this embodiment has lower manufacturing costs for the phosphor substrate 30 than when the support layer 35 is formed of the phosphor layer 36.

[0077] In the case of the light-emitting substrate 10 of this embodiment, the influence of heat generated when the multiple LEDs 22 emit light and heat generated by the excited phosphor layer 36 is taken into consideration, and for example, the thickness of the circuit pattern layer 34 is set to be thicker than that of a normal circuit board (175 μm, for example). In addition, a support layer 35 is interposed between the circuit pattern layer 34 and the phosphor layer 36. Therefore, in the region where the circuit pattern layer 34 is not provided, the volume of the phosphor layer 36 would be large if the support layer 35 were not provided, but in this embodiment, the presence of the support layer 35 allows for sufficient suppression of manufacturing costs.

[0078] [Fifth Effect] In this embodiment, the phosphor layer 36 is not provided and the support layer exposed portion 70 where the support layer 35 is exposed is provided around the optical element mounting region 75 where the light emitting element 20 is mounted. This prevents the phosphor layer from adhering to the optical element mounting region 75 (particularly where the solder paste SP is provided) when the phosphor layer is laminated on the support layer 35, thereby preventing adverse effects on the mounting of the light emitting element 20. Furthermore, the distance from the phosphor layer 36 to the light emitting element 20 in the exposed support layer portion 70 (i.e., the predetermined distance L2 in FIGS. 1C and 1D) is 50 μm to 200 μm. Since the predetermined distance L2 is 50 μm or more, it is possible to effectively prevent the phosphor paint from adhering to the optical element mounting region 75 when laminating the phosphor layer 36. Furthermore, since the predetermined distance L2 is 200 μm or less, it is possible to avoid a situation in which the light output from the light emitting element 20 does not sufficiently reach the phosphor layer 36, thereby preventing a decrease in the color temperature shift function.

[0079] [Sixth Effect] In this embodiment, D1 50 and D2 50 and have the following relationship (Equation 1). (Formula 1)0.8≦D2 50 / D1 50 ≦1.2 With the above configuration, the difference in median diameter between the particles (plurality of phosphor particles and plurality of white particles) in each layer is set to be relatively small. Therefore, in the phosphor substrate 30 of this embodiment, stress occurring at the interface between the support layer 35 and the phosphor layer 36 is reduced.

[0080] Second Embodiment Next, a second embodiment will be described with reference to Fig. 6. Only the parts of this embodiment that are different from the first embodiment (see Fig. 1C, Fig. 3A to Fig. 3E, etc.) will be described below.

[0081] <Configuration of the second embodiment> The light emitting substrate 110 of this embodiment differs from the light emitting substrate 10 of the first embodiment (see FIG. 1C) in that a groove-shaped support layer recess 77 is provided in the support layer exposed portion 70 of the support layer 35.

[0082] <Method for manufacturing phosphor substrate according to second embodiment> The manufacturing method of the light emitting substrate 110 of this embodiment includes the step of forming groove-shaped support layer recesses 77 in addition to the manufacturing method of the first embodiment. As in the case of forming the bonding surface 34A1, the groove-shaped support layer recesses 77 may be formed by removing a part of the support layer 35 by irradiating with laser light, or the support layer 35 may be formed when a photo printing method or a screen printing method is used in the second step (support layer forming step).

[0083] <Effects of the second embodiment> In this embodiment, in addition to the effects of the first embodiment, the support layer recess 77 effectively prevents the phosphor paint from flowing into the optical element mounting area 75 when the phosphor paint is applied during manufacturing.

[0084] As described above, the present invention has been described using the above-mentioned embodiments as examples, but the present invention is not limited to the above-mentioned embodiments. The technical scope of the present invention also includes, for example, the following forms (modifications).

[0085] For example, in the above embodiment, the light-emitting element 20 is an example of a CSP. However, the light-emitting element 20 may be an example other than a CSP. For example, it may simply be a flip-chip mounted element. It may also be applied to the substrate itself of a COB device. In either case, it is sufficient that the area from which light is actually output is above the boundary area between the phosphor layer 36 and the support layer 35 in the thickness direction (+Z direction side).

[0086] In the above embodiment, the phosphor substrate 30 is mounted with a plurality of light-emitting elements 20, and the light-emitting substrate 10 is provided with a plurality of light-emitting elements 20. However, considering the mechanism of the first effect described above, it is clear that the first effect can be achieved even with a single light-emitting element 20. Therefore, the number of light-emitting elements 20 mounted on the phosphor substrate 30 needs to be at least one.

[0087] In the above embodiment, the rear surface pattern layer 38 is provided on the rear surface 33 of the phosphor substrate 30 (see FIG. 1B), but the rear surface pattern layer 38 does not necessarily have to be provided.

[0088] In the description of this embodiment, the phosphor layer 36 is arranged on the insulating layer 31 and the surface 32 of the circuit pattern layer 34 on which the light-emitting element 20 is mounted, except for the plurality of electrode pairs 34A (see FIG. 2B). However, the phosphor layer 36 does not have to be arranged over the entire area of ​​the surface 32 of the phosphor substrate 30, except for the plurality of electrode pairs 34A.

[0089] In addition, in the description of each embodiment, the CS-3305A manufactured by Risho Kogyo Co., Ltd. is used as the motherboard MB when manufacturing the phosphor substrate 30 and the light-emitting substrate 10. However, this is just one example, and a different motherboard MB may be used. For example, the standard specifications of the insulating layer thickness, copper foil thickness, etc. of the CS-3305A manufactured by Risho Kogyo Co., Ltd. are not limited to these, and a thicker copper foil may be used.

[0090] The light emitting substrates 10 and 110 of the embodiments (including their modified examples) can be combined with other components to be applied to a lighting device. In this case, the other components include a power source that supplies power to cause the light emitting elements 20 of the light emitting substrate 10 to emit light.

[0091] This application claims priority based on Japanese Patent Application No. 2022-150193, filed on September 21, 2022, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0092] 10, 110 Light-emitting substrate 20 Light-emitting element 22 LED 24A electrode pair 25 Junction 30, 30A phosphor substrate 31 Insulating layer (an example of an insulating substrate) 34 Circuit Pattern Layer 34x recess 34 34A electrode pair 34A1 Joint surface 34A2 Non-bonded surface 34B Wiring part 34B1 Non-bonded surface 35 Support layer 35b Recessed support layer 35x outer surface 36 Phosphor layer 36x outer surface 37 terminals 38 Backside pattern layer 39 Through holes 70 Exposed support layer 75 Optical element mounting area 77 Support layer recess L light MB Motherboard SP solder paste

Claims

1. A method for manufacturing a phosphor substrate on which at least one light-emitting element is mounted, comprising: a circuit pattern layer forming step of forming a circuit pattern layer on one surface of an insulating substrate to be bonded to the at least one light emitting element; a phosphor layer forming step of forming a phosphor layer on one surface side of the insulating substrate, the phosphor layer including a phosphor having an emission peak wavelength in a visible light region when the emission of the at least one light-emitting element is used as excitation light; a support layer forming step of forming a support layer between the insulating substrate and the phosphor layer, the support layer not containing the phosphor and supporting the phosphor layer; Including, The support layer forming step includes laminating the support layer on the circuit pattern layer in the region where the circuit pattern layer is provided, The phosphor layer forming step is a method for manufacturing a phosphor substrate, in which the light-emitting element is an LED, and the phosphor layer is formed so that the position of the PN junction region, which is the light-emitting region, closest to the insulating substrate is within the thickness direction of the phosphor layer, and so that a portion of the end face of the phosphor layer overlaps with the PN junction region in the thickness direction.

2. The method for manufacturing a phosphor substrate according to claim 1 , wherein the support layer forming step forms a layer having a single layer structure containing a white pigment as the support layer.

3. In the phosphor layer forming step, the phosphor layer is not formed in an area where the light emitting element is to be mounted. The method for producing the phosphor substrate according to claim 1 or 2.

4. The method for manufacturing a phosphor substrate according to claim 3 , wherein the phosphor layer forming step does not form the phosphor layer around an area where the light emitting element is mounted, and forms a support layer exposed portion where the support layer is exposed.

5. 5. The method for manufacturing a phosphor substrate according to claim 4, wherein the distance from the phosphor layer to the light emitting element in the exposed support layer portion is 50 μm to 200 μm.

6. a support layer recess forming step of forming a support layer recess having a recessed shape in the thickness direction in the exposed portion of the support layer, The method for producing the phosphor substrate according to claim 4 .

7. The phosphor is composed of a plurality of phosphor particles, the white pigment contained in the support layer is composed of a plurality of white particles, The volume-based median diameter (D ５０ ) D1 ５０ and a volume-based median diameter (D) of the plurality of white particles measured by a laser diffraction scattering method. ５０ ) D2 ５０ and have the following relationship (Equation 2): The method for producing the phosphor substrate according to claim 1 or 2. (Equation 2) 0.8≦D2 ５０ / D1 ５０ ≤1.2

8. In the support layer forming step, the support layer is formed on one surface of the insulating substrate while a discharge unit that discharges the liquid that does not contain the phosphor is moved relative to the insulating substrate; In the phosphor layer forming step, the phosphor layer is laminated on the support layer while a discharge unit that discharges the liquid containing the phosphor is moved relative to the support layer. The method for producing the phosphor substrate according to claim 1 or 2.

9. In the support layer forming step, the support layer is formed on one surface of the insulating substrate by printing; In the phosphor layer forming step, the phosphor layer is printed and laminated on the support layer. The method for producing the phosphor substrate according to claim 1 or 2.

10. A method for producing a phosphor substrate according to claim 1 or 2; a bonding step of bonding the at least one light emitting element to the circuit pattern layer; Including, A method for manufacturing a light-emitting substrate.

11. The bonding step is performed after the phosphor layer forming step. The method for manufacturing the light emitting substrate according to claim 10 .

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