Method of manufacturing optical member, and light-emitting device

Abstract

To provide a method of manufacturing an optical member that offers superior adhesion to a cover member.SOLUTION: A method disclosed herein for manufacturing an optical member comprises preparing polycrystalline wavelength conversion member having a first surface and a second surface located opposite the first surface and containing phosphor particles, collecting laser light into the wavelength conversion member to form a modified portion inside the wavelength conversion member, and pressing the wavelength conversion member form the first surface side to cut the wavelength conversion member into pieces starting at the modified portion.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing an optical member and a light emitting device. [Background technology]

[0002] A light emitting device is known in which a plate-shaped optical member such as a wavelength conversion member is provided on a light emitting element, and the side surfaces of the light emitting element and the optical member are covered with a reflecting member. As an example, a method of forming a division groove on a first main surface of a base material and fracturing the base material along the division groove to obtain a wavelength conversion member, and a light emitting device in which the side surfaces of the wavelength conversion member are covered with a reflecting member such as a resin have been disclosed (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-97060 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure has an object to provide a method for producing an optical member that has excellent adhesion to a coating member. [Means for solving the problem]

[0005] A method for manufacturing an optical member according to one embodiment of the present disclosure includes the steps of: preparing a polycrystalline wavelength conversion member having a first surface and a second surface opposite to the first surface and containing phosphor particles; focusing laser light inside the wavelength conversion member to form a modified portion inside the wavelength conversion member; and pressing the wavelength conversion member from the first surface side to break the wavelength conversion member starting from the modified portion. Effect of the Invention

[0006] According to an embodiment of the present disclosure, a method for manufacturing an optical member having excellent adhesion to a coating member can be provided. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view illustrating an optical member according to a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] 1A to 1C are schematic diagrams illustrating a manufacturing process of the optical member according to the first embodiment (part 1). [Figure 4] 5A to 5C are schematic diagrams (part 2) illustrating the manufacturing process of the optical member according to the first embodiment. [Diagram 5] 5A to 5C are schematic diagrams (part 3) illustrating the manufacturing process of the optical member according to the first embodiment. [Figure 6] 5A to 5C are schematic diagrams illustrating a manufacturing process of an optical member according to a modified example of the first embodiment. [Figure 7] FIG. 11 is a perspective view illustrating a light emitting device according to a second embodiment. [Figure 8] 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7. [Figure 9] 1 is a laser microscope photograph of a side surface of a wavelength conversion member. [Figure 10] 13 shows the measurement results of Sa and Ra of the side surface of the wavelength conversion member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, a manufacturing method according to an embodiment of the present invention and an optical member obtained by the manufacturing method (hereinafter, sometimes referred to as "optical member according to an embodiment") will be described with reference to the drawings. In the following description, terms indicating specific directions or positions (for example, "upper", "lower", and other terms including these terms) will be used as necessary. However, the use of these terms is for the purpose of facilitating understanding of the invention with reference to the drawings, and the technical scope of the present invention is not limited by the meaning of these terms. Furthermore, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or members.

[0009] In addition, the embodiments shown below are examples of a manufacturing method for an optical member for embodying the technical idea of ​​the present invention, and do not limit the present invention to the following. In addition, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended to be illustrative, and are not intended to limit the scope of the present invention, unless otherwise specified. In addition, the contents described in one embodiment can be applied to other embodiments and modified examples. In addition, the size and positional relationship of the members shown in the drawings may be exaggerated to clarify the explanation. In addition, in order to avoid the drawings becoming overly complicated, a schematic diagram in which some elements are omitted, or an end view showing only a cut surface may be used as a cross-sectional view.

[0010] <Optical member 50 according to the first embodiment> Fig. 1 is a perspective view showing a schematic diagram of an optical member according to a first embodiment. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. In Fig. 1 and Fig. 2, an X direction and a Y direction perpendicular to each other are defined, and a direction perpendicular to the X direction and the Y direction is defined as a Z direction. In other figures, the X direction, the Y direction, and the Z direction may be similarly shown.

[0011] 1 and 2, the optical member 50 is plate-shaped. The optical member 50 has a first surface 50a, a second surface 50b opposite to the first surface 50a, and a side surface 50c continuing to the first surface 50a and the second surface 50b. The side surface 50c connects the outer edge of the first surface 50a to the outer edge of the second surface 50b. In the optical member 50, the first surface 50a and the second surface 50b are flat surfaces.

[0012] The optical member 50 is, for example, a rectangular parallelepiped. In this case, the first surface 50a and the second surface 50b of the optical member 50 are both rectangular, and the optical member 50 has four rectangular side surfaces 50c. The rectangle here means a rectangle or a square. In the example of FIG. 1 and FIG. 2, the first surface 50a and the second surface 50b are parallel to the XY plane. The side surfaces 50c are parallel to the XZ plane or the YZ plane. The Z direction is the height direction (thickness direction) of the optical member 50.

[0013] The optical member 50 is a polycrystalline wavelength conversion member containing phosphor particles. The optical member 50 can convert incident light into light of a different wavelength and emit the converted light. The optical member 50 may emit a part of the incident light. The optical member 50 may convert all of the incident light into light of a different wavelength. In this case, the light incident on the optical member 50 is not emitted from the optical member 50.

[0014] The optical member 50 is a member having translucency. The optical member 50 can be used as a member constituting a light emitting surface of a light emitting device equipped with a light emitting element. The optical member 50 converts light emitted from the light emitting element into light of a different wavelength by making it incident on the second surface 50b, and emits the converted light from the first surface 50a, thereby adjusting the luminous chromaticity of the light emitting device.

[0015] The optical member 50 includes a first region 51 where the particle surface of the phosphor particle is exposed, and a second region 52 where the particle cross section of the phosphor particle is exposed, at different positions in the height direction (Z direction) of the side surface 50c. The particle cross section of the phosphor particle is a cut surface where the phosphor particle is broken. The optical member 50 may include a plurality of first regions 51 spaced apart from each other at different positions in the height direction (Z direction) of the side surface 50c.

[0016] The optical member 50 includes a first region 51 that is disposed continuously over all the side surfaces 50c of the optical member 50 along the outer edge of the first surface 50a of the optical member 50. The optical member 50 may also include a first region 51 that is disposed continuously over all the side surfaces 50c of the optical member 50 along the outer edge of the second surface 50b of the optical member 50. The first region 51 may be disposed discontinuously over all the side surfaces 50c of the optical member 50.

[0017] In the optical member 50, the second region 52 may be disposed continuously over all the side surfaces 50c of the optical member 50, or may be disposed intermittently. The second region 52 may be disposed at different positions in the height direction of the side surface 50c, separated from each other. In this case, the first region is disposed between the second regions. The second region 52 is a surface where the modified portion 50d in the polycrystalline body is exposed on the side surface 50c of the optical member 50. The modified portion 50d can be formed by irradiation with laser light in the manufacturing process of the optical member 50, as described later. The modified portion 50d is a portion where the individual materials constituting the polycrystalline optical member 50 containing phosphor particles are locally melted by the thermal energy of the laser light, and the individual crystal grains are melted and the grain boundaries are partially mixed. The modified portion 50d is formed over the inner region of the second region 52.

[0018] On the side surface of the optical member 50, the first region 51 has a larger surface roughness than the second region 52. The surface roughness of the first region 51 depends on the particle size of the phosphor particles constituting the polycrystalline body, but is, for example, greater than 1.0 μm in arithmetic mean roughness Ra, and is, for example, 2.0 μm or more and 3.0 μm or less. In contrast, the surface roughness of the second region 52 is, for example, 0.5 μm or more and 1.0 μm or less in arithmetic mean roughness Ra.

[0019] Thus, the optical member 50 includes a first region 51 where the particle surface of the phosphor particle is exposed and a second region where the particle cross section of the phosphor particle is exposed, at different positions in the height direction of the side surface 50c. The first region 51 has a larger surface roughness than the second region 52. Therefore, when the optical member 50 is used in a light emitting device or the like and is covered with a covering member 60 such as a resin, the covering member comes into contact with the first region 51 of the optical member 50, thereby improving the adhesion between the covering member 60 and the optical member 50.

[0020] From the viewpoint of adhesion between the optical member 50 and the covering member 60, it is preferable that the side surface 50c of the optical member 50 has a larger area constituted by the first region 51 than the second region 52. In the light-emitting device 1 including the optical member 50 and the covering member 60, by providing the side surface 50c of the optical member 50 with the first region 51 having a larger area, adhesion with the covering member 60 is improved due to the anchor effect of the uneven surface shape in the first region 51.

[0021] Furthermore, the optical member 50 preferably has a second region 52 disposed over all of the side surfaces 50c at a position parallel to the upper end of the side surface 50c. This makes it possible to control the speed at which the uncured resin forming the covering member 60 creeps up the side surface 50c and the variation in height of the covering position that depends on the creeping speed in the manufacturing method of the light-emitting device 1. In other words, by having the second region 52 on the side surface 50c of the optical member 50 at a position parallel to the upper end of the side surface 50c, it is possible to reduce local excessive creeping up of the uncured resin. This makes it possible to reduce the creeping up of the resin to the upper surface of the optical member 50 that constitutes the light-emitting surface of the light-emitting device 1.

[0022] The optical member 50 is a polycrystalline wavelength conversion member containing phosphor particles. Examples of the optical member 50 include a sintered body of a phosphor, a sintered body containing a phosphor and another inorganic material, and the like.

[0023] The phosphor contained in the optical member 50 is an yttrium-aluminum-garnet phosphor (e.g., (Y,Gd)3(Al,Ga)5O 12 :Ce), lutetium aluminum garnet phosphors (e.g., Lu3(Al,Ga)5O 12 :Ce), terbium aluminum garnet phosphors (e.g., Tb3(Al,Ga)5O 12 :Ce), CCA phosphors (e.g., Ca 10 (PO4)6Cl2:Eu), SAE phosphors (e.g., Sr4Al 14 O 25 :Eu), chlorosilicate phosphors (e.g., Ca8MgSi4O 16(Cl2:Eu), silicate phosphors (e.g., (Ba,Sr,Ca,Mg)2SiO4:Eu), β-sialon phosphors (e.g., (Si,Al)3(O,N)4:Eu) or α-sialon phosphors (e.g., Ca(Si,Al) 12 (O,N) 16 :Eu), etc. oxynitride phosphors, LSN phosphors (e.g., (La,Y)3Si6N 11 :Ce), BSESN phosphors (e.g., (Ba,Sr)2Si5N8:Eu), SLA phosphors (e.g., SrLiAl3N4:Eu), CASN phosphors (e.g., CaAlSiN3:Eu) or SCASN phosphors (e.g., (Sr,Ca)AlSiN3:Eu), etc. nitride phosphors, KSF phosphors (e.g., K2SiF6:Mn), KSAF phosphors (e.g., K2(Si 1-x Al x )F 6-x :Mn where x satisfies 0 < x < 1.), or fluoride phosphors such as MGF phosphors (e.g., 3.5MgO·0.5MgF2·GeO2:Mn), quantum dots having a perovskite structure (e.g., (Cs,FA,MA)(Pb,Sn)(F,Cl,Br,I)3 where FA and MA represent formamidinium and methylammonium, respectively), II-VI group quantum dots (e.g., CdSe), III-V group quantum dots (e.g., InP), or quantum dots having a chalcopyrite structure (e.g., (Ag,Cu)(In,Ga)(S,Se)2), etc. can be used.

[0024] The inorganic material contained in the optical member 50 can be aluminum oxide, aluminum nitride, silicon oxide, yttrium oxide, zirconium oxide, magnesium oxide, gadolinium oxide, or yttrium aluminum perovskite (YAP), etc.

[0025] The average particle size of the phosphor particles contained in the optical member 50 can be, for example, 1 μm or more and 30 μm or less. The average particle size of the inorganic material contained in the optical member 50 can be, for example, 1 μm or more and 20 μm or less. The average particle size of each material in the optical member 50 can be calculated from an SEM image taken using a scanning microscope. For example, in an SEM image of a cross section of the optical member 50, the maximum width in the cross section of the crystal phase separated by grain boundaries and the minimum width passing through the center point of the maximum width are measured, the average of the maximum width and the minimum width is defined as the particle size, and the arithmetic average value of the particle size in a specific range in the SEM image at the same magnification is defined as the average particle size.

[0026] <Method for manufacturing optical member according to the first embodiment> A method for manufacturing an optical member according to a first embodiment includes the steps of: preparing a polycrystalline wavelength conversion member having a first surface and a second surface opposite the first surface and containing phosphor particles; focusing laser light inside the wavelength conversion member to form a modified portion inside the wavelength conversion member; and pressing the wavelength conversion member from the first surface side to break the wavelength conversion member starting from the modified portion.

[0027] Hereinafter, each manufacturing step of the method for manufacturing an optical member according to the first embodiment will be described with reference to the drawings.

[0028] Fig. 3 to Fig. 5 are schematic diagrams illustrating the manufacturing process of the optical member according to the first embodiment. Specifically, Fig. 3 and Fig. 4 are perspective views illustrating the manufacturing process of the optical member. Fig. 5 is a cross-sectional view illustrating the manufacturing process of the optical member.

[0029] (Step of preparing wavelength conversion member) First, as shown in Fig. 3, a polycrystalline wavelength conversion member 50S containing phosphor particles is prepared, the polycrystalline wavelength conversion member 50S having a first surface 50a, a second surface 50b opposite to the first surface 50a, and a side surface 50c connected to the first surface 50a and the second surface 50b. In the example of Fig. 3, the first surface 50a and the second surface 50b are parallel to the XY plane. The side surface 50c is parallel to the XZ plane or the YZ plane. The Z direction is the height direction (thickness direction) of the wavelength conversion member 50S. The thickness of the wavelength conversion member to be prepared is, for example, 50 µm or more and 200 µm or less.

[0030] The wavelength conversion member 50S includes a plurality of regions 50R that become the optical members 50 after singulation. In the example of Fig. 3, the regions 50R are arranged two-dimensionally in a matrix shape in a top view of the wavelength conversion member 50S, with boundaries defined by a linear two-dot chain line extending in the X direction and a linear two-dot chain line extending in the Y direction. In the example of Fig. 3, the regions 50R are square in a top view of the wavelength conversion member 50S. Note that the two-dot chain lines are virtual lines indicating boundaries and cannot actually be seen.

[0031] (Process for forming modified portion) Next, as shown in FIG. 4, laser light La is focused inside wavelength conversion member 50S to form modified portion 50d inside wavelength conversion member 50S.

[0032] The laser light La can be emitted from, for example, a picosecond laser device or a femtosecond laser device. The laser light La has, for example, an oscillation wavelength of 700 nm or more and 1500 nm or less. The wavelength conversion member 50S preferably has a light transmittance for the laser light La of 60% or more.

[0033] Specifically, first, as shown by the arrow above in Fig. 4, laser light La is irradiated from a direction substantially perpendicular to the second surface 50b of the wavelength conversion member 50S. The position where the laser light La is irradiated is on the two-dot chain line showing the boundary of the region 50R on the second surface 50b, and the position where the laser light La is focused is a position inside the wavelength conversion member 50S closer to the second surface 50b than the center in the thickness direction (Z direction).

[0034] The laser beam La is irradiated, for example, on a two-dot chain line indicating the boundary of region 50R extending in the Y direction as shown in Fig. 4. As a result, modified portion 50d is formed inside wavelength conversion member 50S along the Y direction in top view as shown below the arrow in Fig. 4. In a step of fracturing the wavelength conversion member described later, the location where modified portion 50d is not formed will crack along the grain boundary starting from modified portion 50d, so modified portion 50d is preferably formed linearly in top view.

[0035] In addition, when there are multiple (here, five) dotted lines indicating the boundaries of region 50R along the Y direction as shown in Figure 3, laser light La is irradiated sequentially along those lines to form modified regions 50d inside each irradiated position.

[0036] Next, the laser light La is irradiated along the two-dot chain lines that indicate the boundaries of the region 50R extending in the X direction. As a result, the modified regions 50d are formed linearly along the X direction in top view inside the wavelength conversion member 50S. When there are multiple (three in this case) two-dot chain lines that indicate the boundaries of the region 50R along the X direction as shown in FIG. 3, the laser light La is irradiated along those lines to form the modified regions 50d inside the respective irradiated positions.

[0037] As a result, the modified portions 50d are formed in a lattice pattern inside the wavelength conversion member 50S at positions that overlap the boundary lines of the regions 50R in a top view of the wavelength conversion member 50S. The modified portions 50d may be formed in the wavelength conversion member 50S at positions spaced apart from the first surface 50a and the second surface 50b, or may be formed in continuity with the first surface 50a and the second surface 50b. In particular, the modified portions 50d are preferably formed at positions spaced apart from the first surface 50a and the second surface 50b. By concentrating and irradiating the laser light La inside the wavelength conversion member 50S, the modified portions 50d can be arranged spaced apart from the surfaces of the wavelength conversion member 50S on the first surface 50a and the second surface 50b side. Such an arrangement of the modified portions 50d can reduce contamination due to adhesion of dust such as fumes and burnout on the surfaces of the first surface 50a and the second surface 50b caused by irradiation of the laser light La when forming the modified portions 50d.

[0038] In the step of forming the modified portion, the modified portion 50d is preferably formed in a region where the depth D from the second surface 50b of the wavelength conversion member 50S is greater than 0 and equal to or less than 10 μm, as shown in Fig. 4. Note that the depth D is the distance in the Z direction from the second surface 50b to the position of the modified portion 50d that is closest to the second surface 50b.

[0039] Considering the ease of breaking wavelength conversion member 50S and the adhesion to covering member 60 in light emitting device 1, modified portion 50d preferably has length L in the depth direction (Z direction) of wavelength conversion member 50S of 2% to 30% of thickness T of wavelength conversion member 50S. Furthermore, modified portion 50d preferably has width W in a direction parallel to second surface 50b of wavelength conversion member 50S of 1 μm to 10 μm.

[0040] By setting the length L of the modified portion 50d to 2% or more of the thickness T of the wavelength conversion member 50S and the width W of the modified portion 50d to 1 μm or more, the wavelength conversion member 50S is easily broken along the modified portion 50d. On the other hand, by setting the length L of the modified portion 50d to 30% or less of the thickness T of the wavelength conversion member 50S and the width W of the modified portion 50d to 10 μm or less, the proportion of the area of ​​the first region on the side surface 50c of the formed optical member 50 can be increased, and the adhesion between the optical member 50 and the covering member 60 can be improved.

[0041] From the viewpoint of ease of breaking wavelength conversion member 50S, length L of modified portion 50d in the depth direction (Z direction) of wavelength conversion member 50S may be 30% or more of thickness T of wavelength conversion member 50S. However, since modified portion 50d is considered to be a region where the wavelength conversion efficiency decreases due to irradiation with laser light, also from the viewpoint of improving the light extraction efficiency of light emitting device 1, it is preferable that length L of modified portion 50d and thickness T of wavelength conversion member 50S be in the above range.

[0042] The modified portion 50d is formed when the energy of the laser beam La at the focusing position exceeds the processing threshold of the material constituting the wavelength conversion member 50S. The greater the energy of the laser beam La at the focusing position, the longer the length L of the modified portion 50d. The width W of the modified portion 50d is smaller than the spot diameter of the laser beam La at the focusing position.

[0043] (Step of breaking the wavelength conversion member) Next, the wavelength conversion member 50S is pressed from the first surface 50a side, and the wavelength conversion member 50S is broken starting from the modified portion 50d. In this step, for example, the wavelength conversion member 50S can be broken by pressing along the straight line of the linear modified portion 50d.

[0044] Specifically, a crack is generated in modified region 50d formed by irradiation with laser beam La, and wavelength conversion member 50S is broken from the crack that propagates from modified region 50d by pressure. In areas where modified region 50d is not formed, the crack propagates between grain boundaries of polycrystalline wavelength conversion member 50S along the pressing direction.

[0045] Here, as an example, a cutting method using a supporting member 310 and a pressing member 320 is shown. First, as shown above the arrow in Fig. 5, supporting member 310 is placed on the second surface 50b side of wavelength conversion member 50S, and wavelength conversion member 50S is pressed from the first surface 50a side by pressing member 320.

[0046] It is preferable that supporting member 310 is elastically deformable by the pressure of pressing member 320. Supporting member 310 can be made of, for example, rubber, resin, metal, etc. When supporting member 310 is elastically deformed by the pressure of pressing member 320, wavelength conversion member 50S is locally pressed, and therefore wavelength conversion member 50S is easily broken along modified portion 50d.

[0047] The pressing member 320 may be one that presses the entire first surface 50a at once, or one that presses the first surface 50a partially. In particular, the pressing member 320 is preferably one that can move on the first surface 50a while pressing partially on the first surface 50a. An example of the pressing member 320 is a member that can move on the first surface 50a while rotating like a roller. The pressing member 320 may be a non-rotating member as long as it can move smoothly on the first surface 50a. In the example of FIG. 5, the pressing member 320 is an elongated cylindrical member, and is arranged with its longitudinal direction facing the Y direction.

[0048] For example, the wavelength conversion member 50S is pressed on the first surface 50a while moving the pressing member 320 in a direction (X direction in the example of FIG. 5) perpendicular to the direction in which the modified portion 50d was formed (Y direction in the example of FIG. 5). As a result, the wavelength conversion member 50S is pressed along the straight line of the modified portion 50d formed in a straight line in a plan view, and as shown below the arrow in FIG. 5, the wavelength conversion member 50S is broken starting from the modified portion 50d. Next, the pressing member 320 is rotated 90 degrees in the XY plane, and the longitudinal direction of the pressing member 320 is oriented in the X direction. Then, the wavelength conversion member 50S is pressed on the first surface 50a while moving the pressing member 320 in the Y direction in FIG. 5. As a result, all the modified portions 50d arranged in a lattice pattern are broken, and a plurality of individualized optical members 50 can be obtained.

[0049] The modified portion 50d formed inside the wavelength conversion member 50S is difficult to observe from the first surface 50a side, and it is difficult to align the pressing position of the pressing member 320 with the position of the modified portion 50d. However, by pressing in one direction while moving the pressing member 320 on the first surface 50a, the modified portion 50d can be easily broken even if the position of the modified portion 50d is not precisely known. Furthermore, by providing the wavelength conversion member 50S with a mark indicating the direction in which the modified portion 50d was formed, the direction in which the modified portion 50d was formed and the direction in which the pressing position of the pressing member 320 moves can be easily aligned.

[0050] Each of the optical members 50 obtained by the cutting includes a first region 51 where the particle surface of the phosphor particle is exposed and a second region 52 where the particle cross section of the phosphor particle is exposed, at different positions in the height direction of the side surface 50c as shown in Figures 1 and 2. The second region 52 is a cut surface of the modified portion 50d.

[0051] In this way, by forming the modified portion 50d inside the wavelength conversion member 50S, even if the length L and width W of the modified portion 50d are small, the wavelength conversion member 50S can be easily fractured along the modified portion 50d, with the modified portion 50d serving as the base point for the crack.

[0052] Furthermore, for example, when the wavelength conversion member 50S is cut by dicing using a blade, a cutting allowance is generated according to the width of the blade. However, in the manufacturing method according to the present embodiment, in which the wavelength conversion member 50S is fractured along the modified portion 50d, a cutting allowance is not substantially generated, and therefore it is possible to increase the number of optical members 50 obtained from the wavelength conversion member 50S.

[0053] <Modification> 6A to 6C are schematic views illustrating the manufacturing process of an optical member according to a modified example of the first embodiment, specifically, perspective views illustrating the manufacturing process of the optical member.

[0054] In the first embodiment, an example was shown in which the laser light La was irradiated from the second surface 50b side, which is the opposite side to the side pressed during cutting (the first surface 50a side). In a modification of the first embodiment, as shown in FIG. 6, the laser light La is irradiated from the side pressed during cutting (the first surface 50a side).

[0055] Specifically, as shown in the upper arrow of Fig. 6, the laser light La is irradiated from a direction substantially perpendicular to the first surface 50a of the wavelength conversion member 50S. The position at which the laser light La is focused is deeper than in the first embodiment. That is, the position at which the laser light La is focused is closer to the second surface 50b than the center in the height direction (Z direction) inside the wavelength conversion member 50S.

[0056] By irradiating laser light La along the dotted line indicating the boundary of region 50R extending in the Y direction, the modified region 50d is formed continuously in a linear shape along the Y direction in top view inside the wavelength conversion member 50S, as shown below the arrow in Figure 6.

[0057] Next, the laser light La is irradiated along an imaginary line that indicates a boundary of the region 50R extending in the X direction. As a result, the modified region 50d is formed continuously and linearly along the X direction in top view inside the wavelength conversion member 50S.

[0058] In this way, even if the laser light La is irradiated from the first surface 50a side, by deepening the focusing position, the modified portion 50d can be formed on the side closer to the second surface 50b as in the first embodiment. Then, as described in the first embodiment with reference to FIG. 5, the wavelength conversion member 50S is pressed from the first surface 50a side to fracture the wavelength conversion member 50S, thereby obtaining a plurality of individualized optical members 50.

[0059] Second Embodiment In the second embodiment, an example of a light emitting device having the optical member according to the first embodiment will be described.

[0060] Fig. 7 is a perspective view showing a schematic diagram of a light emitting device according to a second embodiment. Fig. 8 is a cross-sectional view taken along line VIII-VIII in Fig. 7. Fig. 8 shows a cross section of the light emitting device 1 cut along a plane perpendicular to the upper surface of the light emitting element 20.

[0061] 7 and 8, the light emitting device 1 includes a wiring board 10, a light emitting element 20, a protective element 30, a light guiding member 40, an optical member 50, and a covering member 60. The light emitting device 1 may not include the wiring board 10, the protective element 30, the light guiding member 40, and the covering member 60.

[0062] In the light emitting device 1, the light emitting element 20 is disposed on the wiring board 10. The light emitting element 20 has an upper surface 20a, a plurality of side surfaces 20c continuous with the upper surface 20a, and a lower surface 20b opposite to the upper surface 20a. The plurality of side surfaces 20c are continuous with the upper surface 20a and the lower surface 20b. In other words, the plurality of side surfaces 20c each have an outer edge continuous with the outer edge of the upper surface 20a and the outer edge of the lower surface 20b. In the light emitting element 20, light is emitted from the upper surface 20a, the lower surface 20b, and the side surfaces 20c. Furthermore, in the light emitting device 1, a protective element 30 may be disposed on the wiring board 10.

[0063] The light emitting element 20 has a substantially rectangular upper surface 20a. For example, the light emitting element 20 has an external shape of a substantially rectangular parallelepiped or a substantially quadrangular pyramid. In this case, the upper surface 20a and the lower surface 20b of the light emitting element 20 are substantially rectangular, and the light emitting element 20 has four substantially rectangular or substantially trapezoidal side surfaces 20c. The shape of the upper surface 20a of the light emitting element 20 may be a polygon such as a triangle or a hexagon. The light emitting element 20 may also have an external shape of a columnar body or a pyramid body with a polygonal upper surface.

[0064] The light guide member 40 continuously covers the upper surface 20a of the light emitting element 20 and a plurality of side surfaces 20c connected to the upper surface 20a. Specifically, the light guide member 40 covers the entire upper surface 20a of the light emitting element 20 and at least a part of the upper end side of each side surface 20c (i.e., the outer edge side connected to the upper surface 20a). The light guide member 40 has a side surface 40c that contacts the side surface 20c of the light emitting element 20 and the lower surface of the optical member 50. It is preferable that the light guide member 40 covers a larger area of ​​each side surface 20c of the light emitting element 20, and it is more preferable that the light guide member 40 covers substantially all of each side surface 20c. That is, it is preferable that the side surface 40c of the light guide member 40 contacts the side surface 20c at a position close to the lower end side of each side surface 20c of the light emitting element 20 (i.e., the side connected to the lower surface 20b), and it is more preferable that the side surface 40c contacts the lower end of each side surface 20c. Specifically, on each side 20c of the light-emitting element 20, it is preferable that 75% or more and 100% or less of the area in the height direction from the upper end side is covered by the light-guiding member 40, and it is more preferable that 90% or more and 100% or less of the area is covered by the light-guiding member 40.

[0065] The optical member 50 is disposed on the light emitting element 20 via the light guide member 40. As described in the first embodiment, the optical member 50 is a polycrystalline wavelength conversion member containing phosphor particles, and includes, at different positions in the height direction of the side surface 50c, a first region 51 where the particle surfaces of the phosphor particles are exposed, and a second region 52 where the particle cross sections of the phosphor particles are exposed. Details of the first region 51 and the second region 52 are as described in the first embodiment.

[0066] The first surface 50a of the optical member 50 constitutes a part of the upper surface of the light emitting device 1 as a light extraction surface of the light emitting device 1. The optical member 50 is disposed on the light emitting element 20 such that the second surface 50b of the optical member 50 faces the upper surface 20a of the light emitting element 20 via the light guiding member 40 disposed on the upper surface 20a of the light emitting element 20. The optical member 50 is disposed such that the second surface 50b of the optical member 50 is substantially parallel to the upper surface 20a of the light emitting element 20. It is preferable that the shape of the second surface 50b of the optical member 50 is similar to the shape of the upper surface 20a of the light emitting element. For example, when the upper surface 20a of the light emitting element is rectangular, it is preferable that the second surface 50b of the optical member 50 is also rectangular.

[0067] The second surface 50b of the optical member 50 is preferably larger in area than the upper surface 20a of the light-emitting element 20. In addition, the optical member 50 is preferably arranged so that the second surface 50b of the optical member 50 encloses the light-emitting element 20 in a top view. In addition, in the light-emitting device 1, the light-guiding member 40 interposed between the second surface 50b of the optical member 50 and the upper surface 20a of the light-emitting element 20 preferably covers the second surface 50b of the optical member 50 that does not overlap with the upper surface 20a of the light-emitting element 20 in a top view. Furthermore, in the light-emitting device 1, the light-guiding member 40 is preferably arranged so as to reach the outer edge of the second surface 50b of the optical member 50, and it is more preferable that the entire second surface 50b is covered with the light-guiding member 40. This allows more of the light emitted from the light-emitting element 20 to be incident from the second surface 50b of the optical member 50 via the light-guiding member 40.

[0068] The covering member 60 is provided on the wiring board 10, exposes the first surface 50a which is the upper surface of the optical member 50, and covers the side surface 50c of the optical member 50 and the side surface 20c of the light emitting element 20. The covering member 60 may directly cover the side surface 20c of the light emitting element 20, or may cover it via another member such as the light guiding member 40. Furthermore, when the light emitting device 1 has a protective element 30, the covering member 60 preferably covers the upper surface, lower surface, and side surface of the protective element 30. Furthermore, the covering member 60 may cover the side surface 20c of the light emitting element 20 exposed from the light guiding member 40 and the lower surface 20b of the light emitting element 20.

[0069] By covering the side surface 40c of the light-guiding member 40 with the covering member 60, the light emitted from the side surface 20c of the light-emitting element 20 and transmitted through the light-guiding member 40 is reflected by the covering member 60. Furthermore, by covering the lower surface 20b of the light-emitting element 20 with the covering member 60, the light traveling downward from the light-emitting element 20 is reflected by the covering member 60. As a result, the light extraction efficiency of the light-emitting device 1 can be improved.

[0070] The covering member 60 may be composed of a single member or may be composed of a plurality of members. In the example shown in Fig. 7 and Fig. 8, the covering member 60 is composed of a first covering member 61 and a second covering member 62. The first covering member 61 is provided, for example, on the wiring board 10, and covers the lower surface 20b of the light emitting element 20 and at least a part of the side surface 40c of the light guide member 40. In addition, when the light emitting device 1 has a protective element 30, the first covering member 61 covers, for example, the lower surface and at least a part of the side surface of the protective element 30.

[0071] The second covering member 62 is provided, for example, on the first covering member 61 and covers the side surface of the optical member 50. Furthermore, in the case where the light emitting device 1 has a protective element 30, the second covering member 62 covers, for example, an upper surface of the protective element 30. The second covering member 62 may cover a part of the side surface of the optical member 50 and a part of the side surface of the protective element 30.

[0072] The side surface of the second covering member 62, together with the side surface of the base material 11 of the wiring board 10, constitutes the side surface of the light emitting device 1. The side surface of the second covering member 62 and the side surface of the base material 11 may be, for example, flush with each other. Furthermore, the upper surface of the second covering member 62 and the first surface 50a of the optical member 50 may be, for example, flush with each other.

[0073] Thus, in the light emitting device 1, the optical member 50 includes a first region 51 where the particle surface of the phosphor particle is exposed and a second region where the particle cross section of the phosphor particle is exposed, at different positions in the height direction of the side surface 50c. The first region 51 has a larger surface roughness than the second region 52. Therefore, by contacting the covering member 60 with the first region 51 of the optical member 50, it is possible to improve the adhesion between the covering member 60 and the optical member 50.

[0074] Each element constituting the light emitting device 1 according to the embodiment will be described in detail below.

[0075] [Wiring board 10] The wiring board 10 is a member on which the light emitting element 20 is disposed. The wiring board 10 includes wiring for supplying power to the light emitting element from the outside and a base material 11 that supports the wiring. As an example, the wiring board 10 has an upper surface wiring 12 disposed on the upper surface on which the light emitting element 20 is disposed, and a lower surface wiring 13 disposed on the lower surface opposite to the upper surface. The base material 11 is, for example, substantially rectangular parallelepiped in shape. For the base material 11, it is preferable to use a material that is an insulating material and is difficult to transmit light emitted from the light emitting element 20 and external light. Examples of materials for the base material 11 include ceramics such as aluminum oxide, aluminum nitride, silicon nitride, and mullite, resins such as epoxy resin, silicone resin, modified epoxy resin, urethane resin, phenolic resin, polyimide resin, BT resin, and polyphthalamide, semiconductors such as silicon, and metals such as copper and aluminum, and composite materials thereof. Among these, ceramics having excellent heat dissipation properties can be suitably used as the material for the base material 11.

[0076] The upper wiring 12 includes wiring electrically connected to the light emitting element 20 and wiring electrically connected to the protective element 30. The lower wiring 13 includes an external connection terminal electrically connected to an external power source. For the upper wiring 12 and the lower wiring 13, for example, metals such as iron, copper, nickel, aluminum, gold, silver, platinum, titanium, tungsten, and palladium, or alloys containing at least one of these metals, can be used. Furthermore, the wiring board 10 may include relay wiring inside and / or on the side of the base material 11 for connecting the upper wiring 12 and the lower wiring 13.

[0077] The wiring board 10 does not necessarily have to have the bottom wiring 13. In this case, an external connection terminal that is electrically connected to an external power source may be disposed on the top or side surface.

[0078] The wiring board 10 may have a recess on its upper surface, and the light emitting device 1 may have a structure in which the light emitting element 20 is disposed at the bottom of the recess of the wiring board 10. The light emitting device 1 may also have a structure without the wiring board 10. For example, the light emitting device may have a structure in which a metal member exposed from a covering member 60 covering the lower surface 20b of the light emitting element 20 is provided as an electrode of the light emitting device 1.

[0079] (Light emitting element 20) The light emitting element 20 can be suitably a semiconductor light emitting element such as a light emitting diode (LED) chip or a semiconductor laser (LD) chip. The shape, size, etc. of the light emitting element 20 can be selected arbitrarily. The light emitting element 20 has, for example, a plurality of electrodes 25 on the lower surface 20b. The light emitting element 20 is disposed on the wiring board 10. The light emitting element 20 is flip-chip mounted on the wiring board 10, for example, with the lower surface 20b having the electrodes 25 facing the wiring board 10. The plurality of electrodes 25 of the light emitting element 20 are electrically connected to the upper surface wiring 12. The plurality of electrodes 25 of the light emitting element 20 and the upper surface wiring 12 can be connected using a known member such as eutectic solder, conductive paste, or bump.

[0080] The light emitting element 20 includes, for example, a semiconductor structure and a support substrate that supports the semiconductor structure. The semiconductor structure includes an n-side semiconductor layer, a p-side semiconductor layer, and an active layer sandwiched between the n-side semiconductor layer and the p-side semiconductor layer. The active layer may have a single quantum well (SQW) structure or a multiple quantum well (MQW) structure including multiple well layers. The semiconductor structure includes multiple semiconductor layers made of nitride semiconductors. The nitride semiconductors include In x Al y Ga 1-x-y The term "active layer" includes semiconductors of all compositions in which the composition ratios x and y are changed within the respective ranges in the chemical formula N (0≦x, 0≦y, x+y≦1). The emission peak wavelength of the active layer can be appropriately selected depending on the purpose. The active layer is configured to be capable of emitting, for example, visible light or ultraviolet light.

[0081] The light emitting element 20 may have one semiconductor structure on one support substrate, or may have multiple semiconductor laminates on one support substrate. Furthermore, one semiconductor structure may have only one light emitting layer, or may have multiple light emitting layers. The structure of the semiconductor structure having multiple light emitting layers may be a structure including multiple active layers between one n-side semiconductor layer and one p-side semiconductor layer, or a structure including an n-side semiconductor layer, an active layer, and a p-side semiconductor layer in that order may be repeated multiple times.

[0082] In the light emitting element 20, a plurality of electrodes 25 are disposed on the semiconductor structure. The electrodes 25 include an n-electrode connected to the n-side semiconductor layer and a p-electrode connected to the p-side semiconductor layer. The p-electrode and the n-electrode may be disposed on different surfaces of the semiconductor laminate, or may be disposed on the same surface. Here, the plurality of electrodes 25 including the p-electrode and the n-electrode are disposed on the same surface of the semiconductor structure, and the side on which the plurality of electrodes 25 are disposed constitutes the lower surface 20b of the light emitting element 20, and the surface of the support substrate opposite to the surface on which the semiconductor structure is disposed constitutes the upper surface 20a of the light emitting element 20. Examples of the support substrate include insulating substrates such as sapphire and spinel (MgAl2O4), and nitride-based semiconductor substrates such as gallium nitride. Note that in order to extract the light emitted from the active layer through the support substrate, it is preferable to use a material having translucency for the support substrate. Note that the light emitting element 20 may be configured without a support substrate. In this case, the surface of the semiconductor structure opposite to the surface on which the electrodes are disposed constitutes the upper surface 20a of the light emitting element 20.

[0083] (Protection element 30) The light emitting device 1 may include a protective element 30. The protective element 30 is a member for improving electrostatic breakdown voltage. The protective element 30 is, for example, a Zener diode. The protective element 30 is disposed on the wiring board 10.

[0084] (Light guiding member 40) The light guide member 40 is a member that guides the light emitted from the light emitting element 20 to the optical member 50. By covering the side surface of the light emitting element 20 with the light guide member 40, the light emitted from the side surface of the light emitting element 20 can be easily guided to the optical member 50, and the light extraction efficiency of the light emitting device 1 can be improved. In addition, the light guide member 40 can be used as an adhesive member that bonds the light emitting element 20 and the optical member 50 together.

[0085] The light guide member 40 is disposed so as to cover the upper surface 20a and each side surface 20c of the light emitting element 20. The light guide member 40 covering the side surface 20c of the light emitting element 20 can be formed by spreading the uncured adhesive resin that bonds the optical member 50 and the light emitting element 20 on the side surface 20c of the light emitting element 20 and then curing it. For example, a light-transmitting resin can be used as the adhesive resin that becomes the light guide member 40 after curing. For example, the light-transmitting resin can be a thermosetting resin such as an epoxy resin, a modified epoxy resin, a silicone resin, or a modified silicone resin. Among them, a silicone resin having high heat resistance is preferably used. The light guide member 40 may contain a light diffusing member or a phosphor, which will be described later. The light emitting element 20 and the optical member 50 may be directly bonded to each other without an adhesive resin such as the light guide member 40. In this case, the light emitting device 1 may be configured without the light guide member 40.

[0086] (Covering member 60) The covering member 60 preferably has a light blocking property, specifically, preferably has a light reflecting property and / or a light absorbing property. In particular, it preferably contains a material that can suitably reflect the light emitted from the light emitting element 20. For example, it preferably has a reflectance of 60% or more with respect to the light emitted from the light emitting element 20, and more preferably has a reflectance of 70% or more, 80% or more, or 90% or more.

[0087] The covering member 60 is preferably made of an insulating material. The covering member 60 is, for example, a member in which particles of a light-reflecting substance are contained in a light-transmitting resin. Examples of the resin used for the covering member 60 include resins or hybrid resins containing one or more of silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, urea resin, acrylic resin, phenol resin, bismaleimide triazine resin, and polyphthalamide resin. Among these, it is preferable to use a silicone resin that is particularly excellent in light resistance, heat resistance, and electrical insulation and has flexibility. Examples of light-reflecting substances include titanium oxide, silicon oxide, aluminum oxide, zirconium oxide, magnesium oxide, potassium titanate, barium titanate, zinc oxide, silicon nitride, aluminum nitride, boron nitride, calcium carbonate, calcium hydroxide, calcium silicate, and combinations thereof. Among these, it is preferable to use titanium oxide, which has a relatively high refractive index, from the viewpoint of light reflection.

[0088] As described above, the covering member 60 may be composed of the first covering member 61 and the second covering member 62. In this case, each of the first covering member 61 and the second covering member 62 can be formed using a material selected from the above-mentioned materials exemplified as the material of the covering member 60. By forming the covering member 60 from the first covering member 61 and the second covering member 62, it becomes possible to use a material with high mechanical strength for the second covering member 62 constituting the outer surface of the light emitting device 1, or to use a material with low elasticity and low linear expansion for the first covering member 61 covering the lower surface 20b of the light emitting element 20, thereby alleviating the stress of resin expansion.

[0089] (Operation of light emitting device 1) In the light emitting device 1, when a current is supplied from an external power source to the light emitting element 20, the light emitting element 20 emits light. Of the light emitted by the light emitting element 20, the light traveling upward (i.e., toward the lower surface of the optical member) is extracted to the outside of the light emitting device 1 via the light guiding member 40 and the optical member 50. Of the light emitted by the light emitting element 20, the light traveling downward is reflected by the covering member 60 and the wiring board 10, and is extracted to the outside of the light emitting device 1 via the light guiding member 40 and the optical member 50. Of the light emitted by the light emitting element 20, the light traveling in the lateral direction is reflected at the interface between the side surface 20c of the light guiding member 40 and the covering member 60, and is extracted to the outside of the light emitting device 1 via the light guiding member 40 and the optical member 50.

[0090] As described above, in the light emitting device 1, the optical member 50 includes a first region 51 where the particle surface of the phosphor particle is exposed and a second region where the particle cross section of the phosphor particle is exposed, at different positions in the height direction of the side surface 50c. The first region 51 has a larger surface roughness than the second region 52. Therefore, the covering member 60 contacts the first region 51 of the optical member 50, thereby improving the adhesion between the covering member 60 and the optical member 50. In particular, the first region 51 is disposed adjacent to the upper surface of the optical member 50, which is the light emitting surface of the light emitting device 1, thereby reducing interfacial peeling between the optical member 50 and the covering member 60 on the light emitting surface of the light emitting device 1, and improving the reliability of the light emitting device 1.

[0091] [Example] Examples will be specifically described below, but the present invention is not limited to these examples.

[0092] In Example 1, a polycrystalline wavelength conversion member A containing phosphor particles was prepared. The wavelength conversion member A was a sintered body containing YAG (yttrium aluminum garnet) with a particle size of 2 μm to 4 μm as a phosphor and YAP (yttrium aluminum perovskite) with a particle size of 1.5 μm to 2.5 μm as an inorganic diffusing material, processed into a wafer shape with a thickness of about 180 μm. Next, laser light was focused inside the wavelength conversion member A to form a modified part inside, and then pressure was applied to break the modified part as a starting point.

[0093] In Example 2, a polycrystalline wavelength conversion member B containing phosphor particles was prepared. The wavelength conversion member B was a sintered body containing YAG with a particle size of 8 μm to 15 μm as a phosphor and aluminum oxide with a particle size of 5 μm to 10 μm as an inorganic diffusing material, processed into a wafer shape with a thickness of about 160 μm. Next, a laser beam was focused inside the wavelength conversion member B to form a modified portion therein, and then the modified portion was pressed to break the material starting from the modified portion.

[0094] Next, the side surfaces of five samples each of the cleaved wavelength conversion members A and B were observed under a microscope, and the arithmetic mean height Sa and arithmetic mean roughness Ra of the side surface of each sample were measured. A shape analysis laser microscope, model: VK-X200 (manufactured by Keyence Corporation), was used for observing the side surfaces and measuring Sa and Ra.

[0095] Observation of the side surfaces with a laser microscope confirmed that for both samples of wavelength conversion materials A and B, a first region where the particle surface of the phosphor particle is exposed and a second region where the cross section of the phosphor particle is exposed were found at different positions in the height direction of the side surface. An example of the observation results is shown in Figure 9. Figure 9 is a laser microscope photograph of a part of the side surface of one sample of wavelength conversion material A and a part of the side surface of one sample of wavelength conversion material B. From Figure 9, it can be seen that for both photographs of wavelength conversion materials A and B, a first region with large surface roughness is found on the lower side and a second region with small surface roughness is found on the upper side.

[0096] 10 shows the measurement results of Sa and Ra of the side surface of the wavelength conversion member. For wavelength conversion member A, the average values ​​of five samples were 2.41 μm for Sa in the first region, 0.73 μm for Sa in the second region, 2.42 μm for Ra in the first region, and 0.75 μm for Ra in the second region. For wavelength conversion member B, the average values ​​of five samples were 1.85 μm for Sa in the first region, 0.82 μm for Sa in the second region, 1.34 μm for Ra in the first region, and 0.82 μm for Ra in the second region.

[0097] It was confirmed from Examples 1 and 2 that the surface roughness of the first region and the second region differs depending on the type of phosphor and diffusing material contained in the wavelength conversion member, but in all cases the first region has a larger surface roughness than the second region. Therefore, when the wavelength conversion member is used in a light emitting device or the like and is covered with a covering member such as a resin, it is considered that the contact of the covering member with the first region of the wavelength conversion member improves the adhesion between the covering member and the wavelength conversion member.

[0098] Although preferred embodiments have been described above in detail, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0099] In addition to the above-described embodiment, the following supplementary notes are further disclosed. (Appendix 1) preparing a polycrystalline wavelength conversion member having a first surface and a second surface opposite to the first surface and including phosphor particles; a step of focusing laser light inside the wavelength conversion member to form a modified portion inside the wavelength conversion member; pressing the wavelength conversion member from the first surface side to break the wavelength conversion member starting from the modified portion. (Appendix 2) In the step of breaking, 2. The method for manufacturing an optical member according to claim 1, further comprising: arranging a support member on the second surface side of the wavelength conversion member; and pressing the wavelength conversion member from the first surface side with a pressing member. (Appendix 3) 3. The method for producing an optical member according to claim 2, wherein in the breaking step, the support member is elastically deformable by the pressing force. (Appendix 4) In the step of forming the modified portion, The method for producing an optical member according to any one of claims 1 to 3, wherein the modified portion is formed at a position spaced apart from the first surface and the second surface. (Appendix 5) In the step of forming the modified portion, The method for producing an optical member according to any one of claims 1 to 4, wherein the modified portion is formed in a region of the wavelength conversion member whose depth from the second surface is greater than 0 and is not greater than 10 μm. (Appendix 6) The method for producing an optical member according to any one of claims 1 to 5, wherein the modified portion has a length in a depth direction of the wavelength conversion member that is 2% to 30% of a thickness of the wavelength conversion member. (Appendix 7) The method for producing an optical member according to any one of claims 1 to 6, wherein the modified portion has a width of 1 μm or more and 10 μm or less in a direction parallel to the second surface of the wavelength conversion member. (Appendix 8) In the step of forming the modified portion, the modified portion is formed linearly in a top view, The method for producing an optical member according to any one of claims 1 to 7, wherein in the cleaving, the wavelength conversion member is pressed along the straight line. (Appendix 9) A light-emitting element; a plate-shaped optical member disposed on the light-emitting element; a covering member exposing an upper surface of the optical member and covering a side surface of the optical member and a side surface of the light emitting element, The light emitting device includes a polycrystalline wavelength conversion member containing phosphor particles, and the optical member includes a first region in which the particle surfaces of the phosphor particles are exposed and a second region in which the particle cross sections of the phosphor particles are exposed, at different height positions on a side of the wavelength conversion member. (Appendix 10) 10. The light emitting device of claim 9, wherein the first region has a surface roughness greater than that of the second region. (Appendix 11) The surface roughness of the first region is 2.0 μm or more and 3.0 μm or less in terms of arithmetic mean roughness Ra, 11. The light emitting device according to claim 10, wherein the second region has a surface roughness of 0.5 μm or more and 1.0 μm or less in terms of arithmetic mean roughness Ra. (Appendix 12) 12. The light emitting device according to claim 9, wherein the first region is disposed along an outer edge of a lower surface of the optical member and over all side surfaces of the optical member. [Explanation of symbols]

[0100] 1 Light emitting device 10 Wiring board 11 Base material 12 Top wiring 13 Bottom wiring 20 Light emitting element 20a top surface 20b Bottom side 20c side 25 electrodes 30 Protection elements 40 Light guide member 40c side 50 Optical Components 50d Modification section 50R area 50S Wavelength conversion material 50a Page 1 50b 2nd side 50c side 51 First area 52 Second area 60 Covering material 61 First covering member 62 Second covering member 310 Support member 320 Pressing member

Claims

1. preparing a polycrystalline wavelength conversion member having a first surface and a second surface opposite to the first surface and including phosphor particles; a step of focusing laser light inside the wavelength conversion member to form a modified portion inside the wavelength conversion member; pressing the wavelength conversion member from the first surface side to break the wavelength conversion member starting from the modified portion.

2. In the step of breaking, The method for manufacturing an optical member according to claim 1 , further comprising the steps of: disposing a support member on the second surface side of the wavelength conversion member; and pressing the wavelength conversion member from the first surface side with a pressing member.

3. The method for producing an optical member according to claim 2 , wherein in the step of breaking the support member, the support member is elastically deformable by the pressure.

4. In the step of forming the modified portion, The method for manufacturing an optical member according to claim 1 , wherein the modified portion is formed at a position separated from the first surface and the second surface.

5. In the step of forming the modified portion, The method for manufacturing an optical member according to claim 1 , wherein the modified portion is formed in a region of the wavelength conversion member whose depth from the second surface is greater than 0 and is not greater than 10 μm.

6. The method for producing an optical member according to claim 1 , wherein the length of the modified portion in the depth direction of the wavelength conversion member is 2% to 30% of the thickness of the wavelength conversion member.

7. The method for manufacturing an optical member according to claim 1 , wherein the modified portion has a width of 1 μm or more and 10 μm or less in a direction parallel to the second surface of the wavelength conversion member.

8. In the step of forming the modified portion, the modified portion is formed linearly in a top view, The method for producing an optical member according to claim 1 , wherein in the cleaving step, the wavelength conversion member is pressed along the straight line.

9. A light-emitting element; a plate-shaped optical member disposed on the light-emitting element; a covering member exposing an upper surface of the optical member and covering a side surface of the optical member and a side surface of the light emitting element, The optical element is a polycrystalline wavelength conversion element containing phosphor particles, and the light emitting device includes, at different height positions on a side of the wavelength conversion element, a first region in which the particle surfaces of the phosphor particles are exposed and a second region in which the particle cross sections of the phosphor particles are exposed.

10. The light emitting device according to claim 9 , wherein the first region has a surface roughness greater than that of the second region.

11. The surface roughness of the first region is 2.0 μm or more and 3.0 μm or less in terms of arithmetic mean roughness Ra, The light emitting device according to claim 10 , wherein the second region has a surface roughness of 0.5 μm or more and 1.0 μm or less in terms of arithmetic mean roughness Ra.

12. The light emitting device according to claim 9 , wherein the first region is disposed along an outer edge of a lower surface of the optical member, over all side surfaces of the optical member.

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