Light emitting device and diffusing member used therein

Abstract

To provide a light-emitting device in which an illumination unevenness is reduced.SOLUTION: A light-emitting device contains a light emitting element having a substrate, a wiring formed on the substrate, and an electrode and a diffusion member arranged on a light emission surface side of the light emitting element. In each of a first measurement surface vertical to a light emission surface of a diffusion member in parallel to a first direction while passing through an outer form center of the diffusion member when a main wavelength of the light emitting element is within a range of 500 to 560nm, and the diffusion member is set to a first direction in parallel to one side in a plan view and a second direction orthogonal to the direction, and a second measurement surface vertical to the light emission surface of the diffusion member in parallel to the second direction while passing through the outer form center, as using a reference of a vertical line orthogonal to the light emission surface while passing through the outer form center and extended to a light emission observation direction, when color degrees x and y of a light emission color of the light-emitting device are measured within a range of an angle at the outer form center of -60° or more and 60° or less, a mean value α of a difference of the maximum value and the minimum value of a color difference Δx of the color degree x in the first measurement surface and a difference between the maximum value and the minimum value of a color difference Δx of the color degree x in the second measurement surface is less than 0.0024.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a light emitting device and a diffusing member used therein. [Background technology]

[0002] 2. Description of the Related Art In recent years, development of packages having almost the same size as light-emitting elements, so-called CSPs (Chip Scale Packages), has been progressing as compact light-emitting devices using light-emitting diodes (LEDs).

[0003] As an example of such a light-emitting device, a white light-emitting device equipped with a wavelength conversion member has been proposed, in which a plate-shaped wavelength conversion member containing a phosphor is disposed on a light-emitting element provided on a substrate (for example, Patent Document 1). As another example of a light emitting device having a similar structure, a light emitting device including a light transmissive member is known (for example, Patent Document 2). Patent Document 2 describes the use of a light transmissive member having a diffusion effect, for example, a diffusion member to which a diffusing material is added.

[0004] As light-emitting devices other than white light-emitting devices, for example, blue light-emitting devices and green light-emitting devices use blue light-emitting elements or green light-emitting elements. In recent years, the demand for color LEDs such as blue light-emitting devices and green light-emitting devices is expected to increase in the use of automobile exterior decoration called Car Body Lighting and communication lamps for transmitting information to the outside of the vehicle during automated driving. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-117912 A [Patent Document 2] Patent Publication No. 2021-108358 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in green and blue light emitting CSPs, illumination unevenness may occur due to the structure within the light emitting device.

[0007] Therefore, an object of one embodiment of the present invention is to provide a light emitting device in which illumination unevenness is reduced. Another embodiment of the present invention has an object to provide a diffusing member suitable for reducing illumination unevenness in a light emitting device. [Means for solving the problem]

[0008] The light emitting device according to the first aspect of the present disclosure comprises: A substrate; Wiring formed on the substrate; a light-emitting element having an electrode electrically connected to the wiring; a diffusion member disposed on a light emitting surface side of the light emitting element opposite to a surface on which the electrode is formed, The dominant wavelength of the light-emitting element is within the range of 500 nm to 560 nm, a first direction is parallel to one side of the diffusion member when the diffusion member is viewed in a plan view, and a second direction is perpendicular to the first direction; When the chromaticity x and chromaticity y of the emitted color of the light emitting device are measured on each of a first measurement surface that passes through the center of the outline when the diffusing member is viewed in a plane, is parallel to the first direction, and is perpendicular to the light exit surface of the diffusing member, and a second measurement surface that passes through the center of the outline, is parallel to the second direction, and is perpendicular to the light exit surface of the diffusing member, and when the chromaticity x and chromaticity y of the emitted color of the light emitting device are measured on each of a first measurement surface that passes through the center of the outline when the diffusing member is viewed in a plane, is parallel to the first direction, and is perpendicular to the light exit surface of the diffusing member, the average value α of the difference between the maximum and minimum values ​​of the chromaticity difference Δx of the chromaticity x measured on the first measurement surface and the difference between the maximum and minimum values ​​of the chromaticity difference Δx of the chromaticity x measured on the second measurement surface is less than 0.0024.

[0009] A light emitting device according to a second aspect of the present disclosure, A substrate; Wiring formed on the substrate; a light-emitting element having an electrode electrically connected to the wiring; a diffusion member disposed on a light emitting surface side of the light emitting element opposite to a surface on which the electrode is formed, The dominant wavelength of the light-emitting element is within the range of 420 nm to 560 nm, a first direction is parallel to one side of the diffusion member when the diffusion member is viewed in a plan view, and a second direction is perpendicular to the first direction; When the chromaticity x and chromaticity y of the emitted color of the light emitting device are measured on each of a first measurement surface that passes through the center of the outer shape when the diffusing member is viewed in a plane, is parallel to the first direction, and is perpendicular to the light exit surface of the diffusing member, and a second measurement surface that passes through the center of the outer shape, is parallel to the second direction, and is perpendicular to the light exit surface of the diffusing member, and is based on a perpendicular line that passes through the center of the outer shape and extends in the light emission observation direction perpendicular to the light exit surface, and the angle at the center of the outer shape is in the range of -60° to 60°, the average value β of the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the first measurement surface and the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the second measurement surface is less than 30% of the average value β' obtained by measuring the emitted color of a light emitting device that has a transparent member instead of the diffusing member.

[0010] A light emitting device according to a third aspect of the present disclosure, A substrate; Wiring formed on the substrate; a light-emitting element having an electrode electrically connected to the wiring; a diffusion member disposed on a light emitting surface side of the light emitting element opposite to a surface on which the electrode is formed, The dominant wavelength of the light-emitting element is within the range of 420 nm to 560 nm, a first direction is parallel to one side of the diffusion member when the diffusion member is viewed in a plan view, and a second direction is perpendicular to the first direction; When the chromaticity x and chromaticity y of the emitted color of the light emitting device are measured on each of a first measurement surface that passes through the center of the outline when the diffusing member is viewed in a plane, is parallel to the first direction, and is perpendicular to the light exit surface of the diffusing member, and a second measurement surface that passes through the center of the outline, is parallel to the second direction, and is perpendicular to the light exit surface of the diffusing member, and when the chromaticity x and chromaticity y of the emitted color of the light emitting device are measured on each of a first measurement surface that passes through the center of the outline when the diffusing member is viewed in a plane, is parallel to the first direction, and is perpendicular to the light exit surface of the diffusing member, the average value β of the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the first measurement surface and the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the second measurement surface satisfies the following formula (1). β<0.0006y0+0.0006 (1) Here, y0 is the chromaticity y of the emitted color of the light emitting device measured on the perpendicular line that passes through the center of the outer shape, is perpendicular to the light emitting surface, and extends in the light emission observation direction.

[0011] A light emitting device according to a fourth aspect of the present disclosure, A substrate; Wiring formed on the substrate; a light-emitting element having an electrode electrically connected to the wiring; a diffusion member disposed on a light emitting surface side of the light emitting element opposite to a surface on which the electrode is formed, The dominant wavelength of the light-emitting element is in the range of 420 nm to 480 nm, a first direction is parallel to one side of the diffusion member when the diffusion member is viewed in a plan view, and a second direction is perpendicular to the first direction; When the chromaticity x and chromaticity y of the emitted color of the light emitting device are measured on each of a first measurement surface that passes through the center of the outline when the diffusing member is viewed in a plane, is parallel to the first direction, and is perpendicular to the light exit surface of the diffusing member, and a second measurement surface that passes through the center of the outline, is parallel to the second direction, and is perpendicular to the light exit surface of the diffusing member, and when the chromaticity x and chromaticity y of the emitted color of the light emitting device are measured on each of a first measurement surface that passes through the center of the outline when the diffusing member is viewed in a plane, is parallel to the first direction, and is perpendicular to the light exit surface of the diffusing member, the average value β of the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the first measurement surface and the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the second measurement surface is less than 0.0006.

[0012] The diffusion member according to the present disclosure comprises: A diffusion member arranged on a light emitting surface side of a light emitting element to diffuse light from the light emitting element, a first direction is parallel to one side of the diffusion member when the diffusion member is viewed in a plan view, and a second direction is perpendicular to the first direction; The diffusing member is disposed on a light emitting surface of a light emitting element having a dominant wavelength of 523 nm, and light from the light emitting element is passed through the diffusing member. In each of a first measurement surface that passes through the center of the outline of the diffusing member when viewed in a plane, is parallel to the first direction, and is perpendicular to the light exit surface of the diffusing member, and a second measurement surface that passes through the center of the outline, is parallel to the second direction, and is perpendicular to the light exit surface of the diffusing member, a perpendicular line that passes through the center of the outline and extends in a light emission observation direction perpendicular to the light exit surface is used as a reference, and a measurement value at the center of the outline is obtained. When the chromaticity x and chromaticity y of the emitted color of the light that has passed through the diffusing member are measured within a range of an angle between -60° and 60°, the average value β of the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the first measurement surface and the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the second measurement surface is less than 30% of the average value β' obtained by placing a transparent member instead of the diffusing member on the light-emitting surface of the light-emitting element and measuring the emitted color of the light from the light-emitting element that has passed through the transparent member. Effect of the Invention

[0013] A light emitting device according to one embodiment of the present invention can reduce uneven illumination. A diffusion member according to another embodiment of the present invention is suitable for reducing illumination unevenness in a light emitting device. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic cross-sectional view of a light emitting device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic top view of the light emitting device according to the first embodiment of the present invention. [Diagram 3] FIG. 3 is a schematic perspective view showing the measurement direction of directional chromaticity. [Figure 4] FIG. 4 is a schematic cross-sectional view showing a method for manufacturing the diffusing member. [Diagram 5] 5(a) to 5(c) are schematic cross-sectional views showing a method for manufacturing the diffusing member. [Figure 6] FIG. 6 is a schematic plan view showing a modified example of the method for manufacturing the diffusing member. [Figure 7] 1 is a graph showing the directional chromaticity (Δx) of measurement samples according to Examples 1 to 8. [Figure 8] 1 is a graph showing the directional chromaticity (Δy) of measurement samples according to Examples 1 to 8. [Figure 9] 3 is a photograph of a plane irradiated with light emitted from a measurement sample according to Examples 1 to 8. [Figure 10] 1 is a graph showing the directional chromaticity (Δy) of measurement samples according to Examples 9 to 15. [Figure 11] 1 is a photograph of a plane irradiated with light emitted from a measurement sample according to Examples 9 to 15. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] In the light-emitting device of the present disclosure, the color of the light emitted by the light-emitting device is the same as the color of the light emitted by the light-emitting element, and the directional chromaticity is considered to be constant regardless of the measurement angle. However, when the inventors examined the directional characteristics of the light-emitting device from various viewpoints in order to eliminate the uneven illumination, they discovered that the chromaticity (chromaticity x, y) shifts depending on the measurement angle. Then, when the inventors investigated the relationship between the uneven illumination and the shift in chromaticity x, y (chromaticity difference Δx, Δy), they found that there is a correlation between the difference between the maximum and minimum values ​​of the chromaticity difference Δx, Δy in the range of the measurement angle θ of -60° to 60° and the uneven illumination, and that by suppressing the difference between the maximum and minimum values ​​of the chromaticity difference Δx, Δy in this angle range to less than a predetermined value, a light-emitting device with small uneven illumination can be obtained, and the invention according to the present disclosure was completed.

[0016] The chromaticity differences Δx and Δy can be evaluated more easily than luminance unevenness, and are therefore advantageous as indicators for evaluating and controlling illumination unevenness. Therefore, in an embodiment of the present invention, the difference between the maximum and minimum values ​​of the chromaticity differences Δx and Δy is used as an index for appropriately evaluating illumination unevenness, and a light emitting device with reduced illumination unevenness is provided based on this index.

[0017] The chromaticity difference Δx is mainly suitable as an index for a light emitting device using a light emitting element having a dominant wavelength of 500 nm or more and 560 nm or less (green). The chromaticity difference Δy is suitable as an index for a light emitting device that mainly uses a light emitting element having a dominant wavelength of 420 nm or more and 560 nm or less (blue to green), particularly a light emitting element having a dominant wavelength of 420 nm or more and 480 nm or less (blue). Hereinafter, light emitting devices according to embodiments will be described with reference to the drawings.

[0018] [Embodiment 1: Light-emitting device] In the first embodiment, the chromaticity difference Δx is used to define a light emitting device using a light emitting element with a dominant wavelength of 500 nm or more and 560 nm or less (green).

[0019] The light emitting device 100 shown in FIGS. 1 and 2 has a substrate 1, a light emitting element 2 mounted on the substrate 1, and a diffusing member 30 (including a diffusing layer 3 and a light-transmitting body 4) disposed on the light emitting element 2. Wiring 11 is formed on the substrate 1. An electrode 21 is formed on the lower surface of the light emitting element 2. The light emitting element 2 may be flip-chip mounted on the substrate 1 via a conductive member 7. As a result, the electrode 21 of the light emitting element 2 is electrically connected to the wiring 11 of the substrate 1 via the conductive member 7. The light emitting element 2 has a dominant wavelength in the range of 500 nm to 560 nm.

[0020] The upper surface of the light-emitting element 2 (i.e., the surface opposite to the surface on which the electrode 21 is formed) is the light-emitting surface 23. The diffusing member 30 is disposed on the light-emitting surface 23 side of the light-emitting element 2. The diffusing member 30 may be bonded to the light-emitting element 2 via an adhesive layer 5. The diffusing member 30 may have a covering member 6 disposed along the side surfaces of the light-emitting element 2, the diffusing layer 3, and the translucent body 4.

[0021] The upper surface of the diffusing member 30 (the surface opposite to the surface facing the light-emitting element 2) is a light emitting surface 33. The light emitted from the light-emitting surface 23 of the light-emitting element 2 passes through the diffusing member 30 and is extracted to the outside from the light emitting surface 33.

[0022] Furthermore, the substrate 1 may have a semiconductor element 8 flip-chip mounted via a conductive member 7. The semiconductor element 8 may be omitted as necessary.

[0023] The light emitting device 100 is characterized by a very uniform directional chromaticity in a particular measurement plane. The method for measuring directional chromaticity will now be described in detail.

[0024] The directional chromaticity is measured on each of two measurement planes (first measurement plane Axz and second measurement plane Ayz). First, in a plan view of the diffusing member 30, a first direction x parallel to one side (first side 30a) of the diffusing member 30 and a second direction y perpendicular to the first direction x are defined. The first measurement plane Axz is a measurement plane parallel to the xz plane, (i) passing through the center of the outer shape of the diffusing member 30 when viewed in a plane, (ii) parallel to the first direction x parallel to the first side 30a of the diffusing member 30, and (iii) perpendicular to the light exit surface 33 of the diffusing member 30. The second measurement plane Ayz is a measurement plane parallel to the yz plane, (i) passing through the center of the outer shape of the diffusing member 30 when viewed in a plane, (ii) parallel to the second direction y, and (iii) perpendicular to the light exit surface 33 of the diffusing member 30.

[0025] The "center of the outer shape of the diffusing member 30 when viewed in a plane" refers to, for example, as shown in Fig. 2, when the diffusing member 30 is rectangular when viewed in a plane, the intersection O of the diagonals is the outer shape center of the diffusing member 30. When the diffusing member 30 is another polygon, when all the diagonals intersect at a single point, the intersection of the diagonals is the outer shape center. When all the diagonals do not intersect at a single point, the outer shape center is the center of the circumscribing circle of that outer shape.

[0026] "One side (first side 30a) of the diffusion member 30" refers to any one of the sides when the diffusion member 30 is viewed in a plan view. In the case of a rectangular diffusion member 30 as shown in FIG. 2, the first side 30a refers to any one of the four sides of the diffusion member 30. In the light emitting device 100 in FIG. 2, the first side 30a is a side extending in the x direction, but is not limited to this. When the outer shape of the diffusion member 30 is rectangular, it may be either a long side or a short side. When the outer shape is polygonal, it may be any side that forms the polygon.

[0027] The first direction x is a direction parallel to the first side 30a. The second direction is a direction perpendicular to the first direction x, i.e., the y direction, when the diffusing member 30 is viewed in a plan view. Here, since the diffusing member 30 shown in FIG. 2 is rectangular in a plan view, the second side 30b perpendicular to the first side 30a of the diffusing member 30 is parallel to the second direction y. It should be noted that the second direction y does not need to be parallel to any side of the diffusing member 30. When the diffusing member 30 has a polygonal shape other than a rectangle (e.g., a hexagon), the diffusing member 30 may not have a side perpendicular to one arbitrarily selected side (the first side). In that case, none of the sides of the diffusing member 30 are parallel to the second direction y.

[0028] "A surface perpendicular to light exit surface 33 of diffusing member 30" refers to a surface perpendicular to light exit surface 33 (a surface parallel to the xy plane in FIGS. 1 to 3), such as the xz plane or yz plane.

[0029] Based on these definitions, in the light emitting device 100 shown in Figures 1 to 3, the two measurement planes (first measurement plane and second measurement plane) pass through the intersection point O and are planes parallel to the xz plane and the yz plane, i.e., the Axz plane and the Ayz plane. In this specification, the first measurement surface is the Axz surface and the second measurement surface is the Ayz surface, but they may be interchanged.

[0030] The directional chromaticity is measured with respect to a perpendicular line L (Figures 1 and 3) extending from the center of the outline (intersection O) in the light emission observation direction (z direction) and perpendicular to the light exit surface 33 of the diffusion member 30, with the angle θ at the center of the outline (intersection O) being in the range of -60° or more and 60° or less. In detail, in the measurement on the first measurement plane Axz, the angle θ at the center of the outline (intersection point O) is calculated based on the perpendicular line L. x The measurement is performed in the range of -60° to 60°, that is, in a sector-shaped range of 120° centered on the intersection point O. Similarly, in the measurement on the second measurement plane Ayz, the angle θ at the center of the outline (intersection point O) is calculated based on the perpendicular line L. y The measurement is performed in the range of -60° to 60°, that is, in a sector-shaped range of 120° centered on the intersection point O. The perpendicular line L is parallel to the optical axis of the light emitting device 100 .

[0031] On each of the first measurement surface Axz and the second measurement surface Ayz, the chromaticity x and chromaticity y of the emitted color of the light emitting device 100 are measured within the measurement range. When measuring directional chromaticity (light distribution chromaticity), a current of 1000mA is passed through the light-emitting device to emit light, and the measurement direction is changed by rotating the LED using a goniometer, while measuring the emitted color using a spectral distribution measurement device under Condition B, which is the "average LED luminosity" measurement recommended by the CIE (International Commission on Illumination). The x and y values ​​based on the CIE color system are used to evaluate the emitted color. For the x value, the chromaticity of the emitted color at θ=0° is set as the reference value x0, and the directional chromaticity of the light-emitting device is evaluated by calculating the difference between the maximum and minimum deviations from the reference value x0 (chromaticity difference Δx) for each measurement.

[0032] In the light emitting device 100 according to the first embodiment, the difference between the maximum and minimum values ​​of the chromaticity difference Δx on the first measurement surface Axz (this is Δx1) and the difference between the maximum and minimum values ​​of the chromaticity difference Δx on the second measurement surface Ayz (this is Δx2) are calculated, and the average value α of Δx1 and Δx2, that is, (Δx1+Δx2) / 2, is controlled to be less than 0.0024. By keeping the average value α of Δx1 and Δx2 low, a light emitting device 100 with less illumination unevenness can be obtained.

[0033] In a light-emitting device that does not use a wavelength conversion member, the chromaticity difference Δx does not substantially occur, and therefore it was thought that there would be no difference Δx1 or Δx2 between the maximum and minimum values ​​of the chromaticity difference Δx. Nevertheless, in reality, in a light-emitting device that causes uneven illumination, the chromaticity difference Δx occurs, and the reason why at least one of Δx1 and Δx2 is 0.0024 or more is not clear, but it is speculated as follows. Since a larger current flows near the electrode 21 of the light-emitting element 2, light with a short wavelength is emitted, but as the light moves away from the electrode 21 of the light-emitting element 2, the current decreases slightly and light with a long wavelength is emitted. Therefore, chromaticity unevenness occurs in accordance with the pattern of the electrode 21 of the light-emitting element 2. The illumination pattern of the light emitting device 100 is influenced by the electrode pattern of the light emitting element 2, and therefore it is presumed that this shows a strong correlation with the chromaticity unevenness which is similarly influenced by the electrode pattern of the light emitting element 2.

[0034] An example of the emission color of the light emitting device 100 is a color having a chromaticity x range of 0.04 to 0.25 and a chromaticity y range of 0.45 to 0.77. The emission color in this chromaticity range corresponds to green.

[0035] [Embodiment 2: Light-emitting device] The light emitting device 100 according to the second embodiment is the same as the light emitting device of the first embodiment, except for the type of light emitting element used in the light emitting device 100 and the index used to measure the directional chromaticity. The second embodiment will be described focusing on the differences from the first embodiment.

[0036] In embodiment 2, a light emitting device using a light emitting element with an emission peak wavelength of 420 nm or more and 560 nm or less (blue to green) and a light emitting device using a light emitting element with an emission peak wavelength of 420 nm or more and 480 nm or less (blue) are specified by the chromaticity difference Δy. As described later, the chromaticity difference Δy is particularly preferable as an index for a light emitting device using a light emitting element having an emission peak in the wavelength range of 420 nm or more and 480 nm or less.

[0037] The second embodiment can include three configurations (first to third configurations). Each configuration has a different method for determining the reference value of the index for reducing illumination unevenness of the light emitting device.

[0038] (1) First Form The light emitting device 100 according to the first aspect of the second embodiment, like the first embodiment, has a substrate 1, a light emitting element 2 mounted on the substrate 1, and a diffusing member 30 (including a diffusing layer 3 and a translucent body 4) arranged on the light emitting element 2 (see FIG. 1). The dominant wavelength of the light emitting element 2 is within the range of 420 nm to 560 nm.

[0039] According to the method for measuring directional chromaticity described in detail in the first embodiment, the directional chromaticity is measured on each of the two measurement planes (first measurement plane Axz and second measurement plane Ayz). The directional chromaticity is measured with respect to a perpendicular line L (Figures 1 and 3) extending from the center of the outline (intersection O) in the light emission observation direction (z direction) and perpendicular to the light exit surface 33 of the diffusion member 30, with the angle θ at the center of the outline (intersection O) being in the range of -60° or more and 60° or less.

[0040] On each of the first measurement surface Axz and the second measurement surface Ayz, the chromaticity x and chromaticity y of the emitted color of the light emitting device 100 are measured within the measurement range. For the y value, the chromaticity of the emitted color at θ=0° is set as the reference value y0, and the directional chromaticity of the light-emitting device is evaluated by calculating the difference between the maximum and minimum deviations from the reference value y0 (chromaticity difference Δy) for each measurement.

[0041] In the light emitting device 100 according to the first form of embodiment 2, the difference between the maximum and minimum values ​​of the chromaticity difference Δy on the first measurement surface Axz (defined as Δy1) and the difference between the maximum and minimum values ​​of the chromaticity difference Δy on the second measurement surface Ayz (defined as Δy2) are calculated, and the average value β of Δy1 and Δy2 is calculated.

[0042] In addition, a light emitting device (a comparative light emitting device) having a transparent member instead of the diffusion member 30 is prepared, and the directional chromaticity is measured at each of the two measurement surfaces (first measurement surface Axz, second measurement surface Ayz) in accordance with the directional chromaticity measurement method described in detail in embodiment 1. For the y value of the comparative light-emitting device, the chromaticity of the emitted color at θ=0° is set as the reference value y'0, and the directional chromaticity of the comparative light-emitting device is evaluated by calculating the difference between the maximum and minimum deviations from the reference value y'0 (chromaticity difference Δy') for each measurement. The difference between the maximum and minimum values ​​of the chromaticity difference Δy' on the first measurement surface Axz (this is called Δy'1) and the difference between the maximum and minimum values ​​of the chromaticity difference Δy on the second measurement surface Ayz (this is called Δy'2) are each calculated, and the average value β' of Δy'1 and Δy'2 is then calculated.

[0043] In a first form of the second embodiment, the average value β of the light emitting device 100 is controlled to be less than 30% of the average value β' of the comparative light emitting device, thereby making it possible to obtain a light emitting device 100 with less illumination unevenness.

[0044] A comparative light emitting device including a transparent member may be manufactured, for example, by removing the diffusing member 30 from the light emitting device 100 including the diffusing member 30 and fixing a transparent member in place of the diffusing member 30.

[0045] The first form of embodiment 2 is superior in that it can evaluate a light emitting device 100 having a light emitting element 2 with a dominant wavelength in the range of 420 nm or more and 560 nm or less by using the average value β calculated from Δy as an index, and can evaluate a light emitting device 100 having a light emitting element 2 with a dominant wavelength in the range of 420 nm or more and 480 nm or less in particular.

[0046] When the average value α calculated from Δx is used as an index of illumination unevenness (see embodiment 1), in a light emitting device 100 equipped with light emitting elements 2 having a wavelength range of 420 nm to 480 nm, the difference in the average value α is small between a light emitting device that generates illumination unevenness and a light emitting device that does not generate illumination unevenness. Therefore, in that wavelength range, the average value α is not suitable as an index.

[0047] In contrast, when the average value β calculated from the chromaticity difference Δy is used, the difference in the average value β is large between a light-emitting device that causes illumination unevenness and a light-emitting device that does not cause illumination unevenness over the entire wavelength range of the light-emitting element 2 from 420 nm to 560 nm. Therefore, in the light-emitting device 100 equipped with the light-emitting element 2 having a wavelength range of 420 nm to 480 nm, it is preferable to use the average value β calculated from Δy as an index.

[0048] (2) Second Form The light emitting device 100 according to the second embodiment of the present invention differs from the light emitting device 100 according to the first embodiment in the definition of the average value β of Δy1 and Δy2. Since the rest of the light emitting device 100 according to the second embodiment is the same as the first embodiment, details are omitted.

[0049] In the light emitting device 100 according to the second embodiment, the average value β of the difference Δy1 between the maximum and minimum values ​​of the chromaticity difference Δy on the first measurement surface Axz and the difference Δy2 between the maximum and minimum values ​​of the chromaticity difference Δy on the second measurement surface Ayz is controlled to satisfy the following formula (1). This makes it possible to obtain a light emitting device 100 with less illumination unevenness. β<0.0006y0+0.0006 (1) Here, y0 is the reference value of the chromaticity y of the emitted color at θ=0°. More specifically, y0 is the chromaticity y of the emitted color of the light emitting device 100 measured on a perpendicular line L that passes through the center of the outline of the diffusing member 30 of the light emitting device 100 when viewed in plan, and extends in the light emission observation direction perpendicular to the light exit surface of the diffusing member.

[0050] The second form of the second embodiment uses the average value β calculated from Δy as an index, and is therefore particularly suitable when the dominant wavelength of the light-emitting element 2 is in the range of 420 nm or more and 480 nm or less, similar to the first form.

[0051] (3) The third form The light emitting device 100 according to the third embodiment of the second embodiment differs from the light emitting devices 100 according to the first and second embodiments in the definition of the average value β of Δy1 and Δy2. In addition, the third embodiment is limited to a light emitting device 100 including a light emitting element 2 having a dominant wavelength in the range of 420 nm to 480 nm. Other than that, it is the same as the first and second embodiments, so details are omitted.

[0052] In the light emitting device 100 according to the third embodiment of the second embodiment, the average value β of the difference Δy1 between the maximum and minimum values ​​of the chromaticity difference Δy on the first measurement surface Axz and the difference Δy2 between the maximum and minimum values ​​of the chromaticity difference Δy on the second measurement surface Ayz is controlled to be less than 0.0006. This makes it possible to obtain a light emitting device 100 with less uneven illumination.

[0053] An example of the emission color of the light emitting devices 100 according to the first to third forms of embodiment 2 is a range of chromaticity x from 0.04 to 0.25 and a range of chromaticity y from 0.01 to 0.77. The emission color in this chromaticity range corresponds to blue to green.

[0054] [Embodiment 3: Diffusion member] In the third embodiment, a diffusing member 30 suitable for the light emitting device 100 according to the first and second embodiments will be described. 1, the diffusing member 30 is disposed on the light emitting surface side of the light emitting element 2 to diffuse light from the light emitting element 2. The diffusing member 30 is defined by a chromaticity difference Δy obtained from the measurement results of the characteristics using the light emitting element 2 of a specific wavelength (523 nm).

[0055] In the measurement, a diffusing member 30 is placed on the light emitting surface of a light emitting element 2 having a dominant wavelength of 523 nm, and light from the light emitting element 2 is passed through the diffusing member 30. The directional chromaticity of the light that has passed through the diffusing member 30 is measured at each of two measurement surfaces (first measurement surface Axz and second measurement surface Ayz) according to the method for measuring directional chromaticity described in detail in the first embodiment. The directional chromaticity is measured with respect to a perpendicular line L (Figures 1 and 3) extending from the center of the outline (intersection O) in the light emission observation direction (z direction) and perpendicular to the light exit surface 33 of the diffusion member 30, with the angle θ at the center of the outline (intersection O) being in the range of -60° or more and 60° or less.

[0056] On each of the first measurement surface Axz and the second measurement surface Ayz, the chromaticity x and chromaticity y of the emitted color of the light that has passed through the diffusing member 30 within the above measurement range are measured. For the y value, the chromaticity of the emitted color at θ=0° is set as the reference value y0, and the directional chromaticity characteristics of the diffusion member 30 are evaluated by calculating the difference between the maximum and minimum deviations from the reference value y0 (chromaticity difference Δy) for each measurement.

[0057] For light that has passed through the diffusing member 30, the difference between the maximum and minimum values ​​of the chromaticity difference Δy on the first measurement surface Axz (this is referred to as Δy1) and the difference between the maximum and minimum values ​​of the chromaticity difference Δy on the second measurement surface Ayz (this is referred to as Δy2) are each calculated, and the average value β of Δy1 and Δy2 is further calculated.

[0058] In addition, for light that passes through a transparent member instead of the diffusing member 30, the directional chromaticity is measured at each of two measurement surfaces (first measurement surface Axz, second measurement surface Ayz) in accordance with the directional chromaticity measurement method described in detail in embodiment 1. For the y value, the chromaticity of the emitted color at θ=0° is set as the reference value y'0, and the directional chromaticity of the light passing through the transparent material is evaluated by calculating the difference between the maximum and minimum deviations from the reference value y'0 (chromaticity difference Δy') for each measurement. The difference between the maximum and minimum values ​​of the chromaticity difference Δy' on the first measurement surface Axz (this is called Δy'1) and the difference between the maximum and minimum values ​​of the chromaticity difference Δy on the second measurement surface Ayz (this is called Δy'2) are each calculated, and the average value β' of Δy'1 and Δy'2 is then calculated.

[0059] In the third embodiment, the average value β of the light passing through the diffusion member 30 is controlled to be less than 30% of the average value β' of the light passing through the transparent member. This makes it possible to obtain a light emitting device 100 with less illumination unevenness when applied to the light emitting device 100.

[0060] [Common to embodiments 1 to 3] The components of the light emitting device 100 capable of realizing the directional chromaticity characteristics of the first and second embodiments, and the diffusing member of the third embodiment will be described in detail below.

[0061] (substrate) The substrate 1 is a member for arranging the light emitting element, and has wiring for electrically connecting the electrode of the light emitting element 2 and the external electrode. The main material of the substrate 1 is preferably an insulating material that is difficult for light from the light emitting element and external light to transmit. For example, ceramics such as alumina and aluminum nitride, resins such as phenol resin, epoxy resin, polyimide resin, BT resin, and polyphthalamide can be mentioned. When using a resin, inorganic fillers such as glass fiber, silicon oxide, titanium oxide, and alumina can be mixed into the resin as necessary. This can improve the mechanical strength, reduce the thermal expansion coefficient, and improve the light reflectance. The wiring is formed in a predetermined pattern on the insulating material, and the wiring material can be at least one selected from gold, silver, copper, and aluminum. The wiring can be formed by appropriately selecting a method of metal plating or a method of arranging a metal foil.

[0062] (Light emitting element) A light-emitting diode is preferable as the light-emitting element 2. The light-emitting element 2 suitable for measuring the characteristics of the light-emitting devices according to the first and second embodiments, and the diffusing member according to the third embodiment will be described in detail below.

[0063] (i) Embodiment 1 In the first embodiment, the light emitting element 2 preferably has a dominant wavelength in the range of 500 nm to 560 nm (green emission). By using the light emitting element 2 having this emission wavelength, a light emitting device that emits green light can be obtained.

[0064] When the sensitivity of the human eye to light (visibility) is high, the brightness is perceived as high, so when evaluating and controlling lighting unevenness based on the brightness unevenness, accurate brightness measurement may be difficult with light emission in a wavelength range with high visibility. On the other hand, the measurement sensitivity of chromaticity x is not wavelength dependent (chromaticity dependent), so accurate chromaticity measurement can be performed even for light emission with high visibility. Since green light emission having a dominant wavelength in the range of 500 nm to 560 nm has high luminosity, a green light emitting device is particularly suitable as a target for evaluating and controlling illumination unevenness using the chromaticity difference Δx as an index.

[0065] A specific example of the light-emitting element 2 is a green light-emitting element using a nitride semiconductor. The light-emitting wavelength can be selected from a variety of wavelengths depending on the material of the semiconductor layer and its mixed crystal degree. As described above, the light-emitting element 2 having a dominant wavelength in the range of 500 nm to 560 nm is particularly suitable.

[0066] (ii) Embodiment 2 In the second embodiment, the light emitting element 2 preferably has a dominant wavelength in the range of 420 nm to 560 nm (blue to green emission). By using the light emitting element 2 having this emission wavelength, a light emitting device that emits blue to green light can be obtained.

[0067] As in the first embodiment, the measurement sensitivity of the chromaticity y has no wavelength dependency (chromaticity dependency), so accurate chromaticity measurement can be performed regardless of the visual sensitivity. Blue to green light emitting devices are suitable as targets for evaluating and controlling illumination unevenness using the chromaticity difference Δy as an index. In particular, it is more preferable to evaluate the light emitting element 2 having a dominant wavelength in the range of 420 nm to 480 nm (blue light emission) using Δy. Therefore, the light emitting element 2 emitting blue light is suitable for the second embodiment, which is evaluated using the chromaticity difference Δy.

[0068] A specific example of the light-emitting element 2 is a blue to green light-emitting element using a nitride semiconductor. The light-emitting wavelength can be selected from a variety of wavelengths depending on the material of the semiconductor layer and its mixed crystal degree. As described above, the light-emitting element 2 having a dominant wavelength in the range of 420 nm to 560 nm (particularly, 420 nm to 480 nm) is particularly suitable.

[0069] (iii) Embodiment 3 In the third embodiment, a light-emitting element 2 with a specific wavelength (dominant wavelength of 523 nm (green light emission)) is used to measure the characteristics of the diffusion member 30. By using the light-emitting element 2 with a dominant wavelength of 523 nm (green light emission), it is possible to provide a diffusion member 30 suitable for both the light-emitting device 100 specified using the chromaticity difference Δx as in the first embodiment and the light-emitting device 100 specified using the chromaticity difference Δy as in the second embodiment.

[0070] (Diffusion material) The diffusion member 30 is a member that scatters light from the light-emitting element 2. An example of the diffusion member 30 is one in which a diffusion layer is provided on the surface of a light-transmitting body. Note that, since members such as those in which the surface of a light-transmitting body is provided with unevenness, and those in which a light-diffusing film is attached to the surface of a light-transmitting body also exhibit the same function as the diffusion member, they are also included in the diffusion member in this specification. These diffusion members 30 are adjusted so as to impart the desired optical characteristics (directional chromaticity) as described above to the light-emitting device 100. For example, the amount of diffusion material added to the diffusion layer, the degree of unevenness on the surface of the light-transmitting body, and the selection of the light-diffusing film are appropriately controlled.

[0071] The diffusing member 30 preferably includes a light-transmitting body 4 and a diffusing layer 3 disposed between the light-transmitting body 4 and the light-emitting surface 23 of the light-emitting element 2. Preferred embodiments of the diffusing layer 3 and the light-transmitting body 4 will be described in detail below.

[0072] (Diffusion layer) The diffusion layer 3 includes, for example, a resin 31 and a particulate diffusion material 9 disposed in the resin 31. The resin 31 functions as a binder for the diffusion material 9. By appropriately controlling the concentration and particle size of the diffusing material 9 added to the diffusing member 30, the optical characteristics (directional chromaticity) of the light emitting device 100 using the diffusing member 30 can be controlled within a desired range.

[0073] The concentration of the diffusing material 9 in the diffusing layer 3 is preferably in the range of 0.1% by mass to 20% by mass, when the resin 31 is taken as 100% by mass, and can suppress a decrease in luminous flux while exerting a desired light diffusion effect. The concentration of the diffusing material 9 is more preferably in the range of 3.0% by mass to 15.0% by mass, and most preferably in the range of 5.0% by mass to 10.0% by mass, when the resin 31 is taken as 100% by mass.

[0074] In the first embodiment, when the diffusing member contains the diffusing material 9, the particle size of the diffusing material 9 is set to be 0.1 μm or more and 2.0 μm or less.

[0075] The "concentration of the diffusing material" and the "particle size of the diffusing material" are determined by the following method. The concentration and particle size of the diffusing material 9 contained in the diffusing member 30 are obtained using an SEM-EDX image of a cross section of the diffusing member 30. In the SEM-EDX measurement, a 10 μm×10 μm range (observation range) is observed at a position approximately half the thickness of the diffusing member 30 from the side facing the light emitting element in a cross section cut in the thickness direction of the diffusing member 30. Then, within the observation range, the diffusing material 9 contained in the diffusing member 30 is identified. With the dimensions of this observation range, several tens to a hundred diffusing materials can be measured, and can be obtained in one measurement.

[0076] The particle size of the diffusing material is obtained from the SEM-EDX image by the following procedure. The concentration of the diffusing material is then calculated (estimated) from the particle size of the diffusing material. Note that although the concentration of the diffusing material can be easily determined during manufacturing, it is difficult to measure it accurately in the state of the light emitting device, so the value roughly calculated using the method described below is treated as the "concentration of the diffusing material."

[0077] (Particle size of diffusion material) The maximum diameter (maximum dimension) of each particle of the diffusion material 9 included within the observation range of the SEM-EDX image (excluding particles on the border of the observation range) is measured. The central value (median value) is calculated from the frequency distribution (volume basis) of the maximum diameters, and this is regarded as the particle size of the diffusion material 9.

[0078] (concentration of diffusion material) For the diffusing material being considered when calculating the concentration of the diffusing material, it is assumed that the thickness in the depth direction of the observation area is very thin, that there is no overlap of particles in the depth direction of the observation area, and that this does not have a significant impact on the approximate calculation of the concentration of the diffusing material. Based on this premise, it is assumed that in the observation area, (total area of ​​the diffusing material) ≒ (total volume of the diffusing material) and (cross-sectional area of ​​the diffusing material) ≒ (volume of the diffusing material).

[0079] The total area of ​​the diffusion material in the observation area (10 μm × 10 μm = 100 μm 2 ) is the total volume V1 of the diffusing member. Next, from the "maximum diameter of the diffusion material" obtained by the above method, the cross-sectional area of ​​each diffusion material particle (π × (maximum diameter (μm) / 2) 2 ) is calculated. The total cross-sectional area of ​​the diffusing material contained within the observation area is calculated by multiplying the number of diffusing material particles counted when calculating the particle size by the calculated "cross-sectional area of ​​each diffusing material particle." The calculated total cross-sectional area of ​​the diffusing material is taken as the total volume V2 of the diffusing material. Then, the total volume V2 of the diffusing material is subtracted from the total volume V1 of the diffusing member to obtain the volume V3 of the resin (V3=V1-V2).

[0080] The mass of the diffusing material contained within the observation area is roughly calculated by multiplying the total volume V2 of the diffusing material by the specific gravity of the diffusing material. Also, the mass of the resin contained within the observation area is roughly calculated by multiplying the volume V3 of the resin by the specific gravity of the resin. Using these calculation (approximate) results, the concentration (mass %) of the diffusing material relative to 100 mass % of the resin is calculated.

[0081] The diffusion material 9 has a large refractive index difference with the resin 31, and light is reflected at the interface between the diffusion material 9 and the resin 31. The diffusion material 9 used in the first embodiment is made of a material having a refractive index difference with the resin of 0.2 or more. This allows the diffusion material to exhibit light diffusion performance. When a light-transmitting resin (e.g., silicone resin or epoxy resin) that is normally used in this technical field is used as the resin 31, the diffusion material 9 can be made of aluminum oxide, titanium oxide, yttrium phosphate, calcium carbonate, barium sulfate, silicone fine particles, acrylic fine particles, boron nitride, aluminum nitride, calcium phosphate, etc., either alone or in combination of two or more. In particular, it is preferable that the diffusion material be one or more selected from the group consisting of aluminum oxide, titanium oxide, and yttrium phosphate. Basically, the diffusion layer 3 does not contain a phosphor, but may contain a small amount of phosphor as long as the desired optical characteristics of the light emitting device 100 are not impaired.

[0082] The thickness of the diffusion layer 3 is preferably 20 to 100 μm, and more preferably 20 to 50 μm.

[0083] A filler may be contained in the diffusion layer 3. The filler used in the embodiment 1 preferably has a particle size of 0.5 μm or more and 40 μm or less. The particle size of the filler is measured in the same manner as the particle size of the diffusion material. Adding a filler to the diffusion layer 3 can reduce aggregation of the diffusion material 9 in the diffusion layer 3. Furthermore, by highly filling the resin 31 with fillers having large particle sizes, expansion and contraction of the diffusion layer 3 due to temperature changes can be suppressed, which contributes to improving the reliability of the light emitting device 100. Furthermore, by using a filler with a higher thermal conductivity than the resin 31 and arranging it on the light emitting element side, the heat trapped in the resin 31 can be transferred to the light emitting element 2 side, improving the heat dissipation of the diffusion layer 3, which can contribute to improving the reliability of the light emitting device 100.

[0084] The filler is preferably silicon oxide particles. In particular, when the particles are spherical, the effect of adding the filler is significant because the particles can be densely packed in the diffusion layer 3. As the silicon oxide particles, KYKLOS MSR-11 (spherical silica manufactured by Tatsumori Co., Ltd.) is preferable.

[0085] (Transparent material) A transparent member is used in place of the diffusing member 30 in embodiments 2 and 3 to obtain comparative data. The transparent member is a member that does not substantially contain the diffusing material 9 (a member in which the concentration of the diffusing material is substantially 0% by mass). The transparent member can be made of a transparent material such as resin or glass. The transparent member may contain a filler, similar to the diffusing member 30 .

[0086] The transparent member made of resin can be manufactured from a resin paste that does not contain a diffusing material. For example, similar to the manufacturing method of the diffusing member 30 described later, the transparent member may be manufactured by disposing a resin paste that does not contain a diffusing material 9 on one main surface of the light-transmitting body 4 and curing the resin paste (see Fig. 4 and Fig. 5(a)). Since the resin paste does not contain the diffusing material 9, the light-transmitting body 4 may or may not be inverted so that the two main surfaces of the light-transmitting body 4 are upside down.

[0087] The transparent member made of glass can be manufactured from, for example, a transparent plate glass. The transparent member made of a transparent glass plate is bonded to one main surface of the light-transmitting body 4 using a transparent adhesive. The adhesive may be the same as that used for the adhesive layer 5.

[0088] As described above, a separate transparent member may be formed on the light-transmitting body 4, but the light-transmitting body 4 and the transparent member may be formed as one member. Specifically, when the light-transmitting body 4 and the transparent member are formed from the same material (for example, the same resin material or the same glass material), one transparent resin plate or one transparent glass plate may be processed to desired dimensions and used as a member that serves as both the light-transmitting body 4 and the transparent member.

[0089] (Translucent body) The light-transmitting body 4 is a member that supports the diffusion layer 3 formed on its surface. The light-transmitting body 4 can be a plate-shaped body made of a light-transmitting material such as glass or resin. The glass can be selected from, for example, borosilicate glass, quartz glass, low-alkali glass, and aluminosilicate glass. The resin can be selected from, for example, silicone resin, epoxy resin, acrylic resin, and polyimide resin. The thickness of the light-transmitting body 4 may be any thickness that does not reduce the mechanical strength during the manufacturing process and has sufficient mechanical strength to support the diffusion layer 3. If the thickness of the light-transmitting body 4 is too thick, it will hinder the miniaturization of the light-emitting device, so it is preferable to set the thickness to an appropriate thickness. The main surface of the light-transmitting body 4 (the main surface on which the diffusion layer 3 is formed) is preferably larger than the upper surface (light-emitting surface 23) of the light-emitting element 2. By arranging the diffusion layer 3 over the entire main surface of the translucent body 4, when the translucent body 4 with the diffusion layer 3 arranged thereon is arranged on the upper surface (light-emitting surface 23) of the light-emitting element 2, even if some deviation in mounting accuracy occurs, the diffusion layer 3 can be reliably arranged over the entire upper surface (light-emitting surface 23) of the light-emitting element 2.

[0090] (Adhesive layer) The diffusion member 30 is preferably bonded to the light emitting element 2 via an adhesive layer 5 between the light emitting element 2 and the diffusion layer 3. When the adhesive layer 5 is used, the adhesive constituting the adhesive layer 5 is preferably a material capable of guiding the light emitted from the light emitting element 2 to the diffusion layer 3 and optically connecting the light emitting element 2 and the diffusion layer 3. Specific examples include organic resins such as silicone resin, epoxy resin, phenol resin, and polyimide resin, with silicone resin being preferred. The thinner the adhesive layer 5, the more preferable it is. This is because the thinner the adhesive layer 5, the better the heat dissipation and the less loss of light passing through the adhesive layer 5, thereby improving the light output from the light emitting device.

[0091] The adhesive layer 5 is preferably disposed not only between the light emitting element 2 and the diffusion layer 3 but also on the side of the light emitting element 2. This is because the outer surface of the adhesive layer 5 disposed on the side of the light emitting element 2 can reflect the light emitted from the side of the light emitting element 2 and make it enter the diffusion layer 3, thereby improving the light extraction efficiency of the light emitting device 100. In particular, as shown in FIG. 1, in the side of the light emitting element 2, in a vertical cross-sectional view, the adhesive extends to the corner formed from the side of the light emitting element 2 and the diffusion layer 3 protruding from the upper surface of the light emitting element, and the thickness of the extended adhesive layer 5 is preferably triangular in cross section, decreasing toward the lower portion of the light emitting element 2. Furthermore, it is preferable that a part of the covering member 6 is disposed so as to contact the adhesive layer 5 with a triangular cross section, and that a part of the covering member 6 is tapered. As a result, the light emitted from the side of the light emitting element 2 is reflected at the interface between the adhesive layer with a triangular cross section and the tapered covering member 6. Furthermore, since the area of ​​the diffusion layer 3 is larger than the top surface of the light emitting element 2, the light can easily enter the outer periphery of the diffusion layer 3 that protrudes outward from the top surface of the light emitting element 2, further improving the luminance of the light emitting device 100. Such protrusion of the adhesive layer 5 can also be formed by adjusting the amount of adhesive used to adhere the diffusion member 30 to the top surface of the light emitting element 2, and allowing the excess adhesive other than the amount necessary for adhesion to the top surface of the light emitting element 2 to protrude onto the side surface of the light emitting element 2.

[0092] It is also preferable that the main material of the resin 31 of the diffusion layer 3 and the adhesive of the adhesive layer 5 are the same type (preferably the same material). For example, when a silicone resin is used for the resin 31 of the diffusion layer 3, it is preferable that a silicone resin is also used for the adhesive of the adhesive layer 5. Since the refractive index difference between the diffusion layer 3 and the adhesive layer 5 can be reduced, it is possible to increase the amount of light incident from the adhesive layer 5 to the diffusion layer 3.

[0093] (Semiconductor element) The semiconductor element 8 may be disposed on the substrate 1 adjacent to the light emitting element 2, separately from the light emitting element 2. Examples of such a semiconductor element 8 include a transistor for controlling the light emitting element and a protective element described below, in addition to another light emitting element that is not intended to emit light from the light emitting device 100. The protective element is an element for protecting the light emitting element 2 from element destruction or performance deterioration due to application of an excessive voltage. Specifically, the protective element is composed of a Zener diode that becomes conductive when a voltage equal to or higher than a specified voltage is applied. The protective element is a semiconductor element 8 having a p-electrode and an n-electrode similar to the light emitting element 2, and is inversely parallel to the p-electrode and n-electrode of the light emitting element 2, that is, the n-electrode and the p-electrode of the light emitting element 2 are electrically connected to the p-electrode and the n-electrode of the protective element by the conductive member 7, respectively. In the case of the protective element, similar to the case of the light emitting element 2, the electrodes of the protective element can be bonded to the wiring of the substrate 1 via the conductive member 7 by placing the electrodes of the protective element on the conductive members 7 and applying heat, ultrasonic waves, and a load.

[0094] It is preferable that the height of the semiconductor element 8 when placed on the substrate 1 is lower than the combined height of the light-emitting element 2, the diffusion layer 3, and the light-transmitting body 4. This is because it makes it easier to cover the semiconductor element 8 with the covering member 6.

[0095] (Covering material) The covering member 6 is arranged as necessary to cover at least a part of the side surface of the light emitting element 2 and at least a part of the side surface of the diffusion member 30 in order to increase the front luminance of the light emitting device 100. When the covering member 6 is used, it is preferable to use an insulating material as the material. In addition, in order to secure a certain degree of strength, for example, a thermosetting resin, a thermoplastic resin, etc. can be used. More specifically, silicone resin, epoxy resin, BT resin, PPA, or phenol resin can be mentioned. In addition, by dispersing powder of a material (for example, the same material as the diffusion material added to the diffusion layer 3 as described above) that does not easily absorb light from the light emitting element 2 and has a large refractive index difference with respect to the base resin in these base resins, it is possible to efficiently reflect light.

[0096] The filling of the material for forming the covering member 6 can be carried out, for example, by using a resin discharger that can be moved (moved) as desired relative to the substrate 1 above the fixed substrate 1. That is, for example, the resin discharger filled with resin is moved while discharging liquid resin from a nozzle at the tip, thereby injecting the material for the covering member 6 near the light emitting element 2 and the semiconductor element 8. The moving speed of the resin discharger can be appropriately adjusted according to the viscosity and temperature of the resin used. The discharge amount can be adjusted by keeping the pressure applied during discharge constant. The viscosity of the material for the covering member 6 is 0.35 to 13.0 Pa·s, preferably 3.0 to 5.5 Pa·s at room temperature (20±5°C).

[0097] (Conductive material) When the conductive member 7 is used, a bump can be used as the conductive member 7, and the material of the bump can be Au or an alloy thereof, and eutectic solder (Au-Sn), Pb-Sn, lead-free solder, etc. can be used as the other conductive member 7. Note that, although Fig. 2 shows an example in which a bump is used as the conductive member 7, the conductive member 7 is not limited to a bump and may be, for example, a conductive paste.

[0098] (Underfill) The underfill is a member for protecting the light emitting element 2, the semiconductor element 8 separate from the light emitting element 2, the conductive member 7, etc., arranged on the substrate 1, from dust, moisture, external impact, etc. The underfill can be placed in the gaps between the substrate 1 and the light emitting element 2 or the semiconductor element 8, or in the gaps between the conductive member 7 and another conductive member 7.

[0099] Examples of materials for the underfill include silicone resin, epoxy resin, urea resin, etc. In addition to these materials, colorants, diffusing materials, fillers, phosphors, etc. can also be included as necessary.

[0100] [Embodiment 4: Method for producing light-emitting device and diffusing member] An example of a method for manufacturing the light emitting device 100 according to the first and second embodiments and the diffusing member according to the third embodiment will be described.

[0101] (Method of manufacturing the diffusion member 30) 4 and 5(a) to 5(c) are schematic cross-sectional views showing a method for manufacturing the diffusing member 30. As shown in FIG. Resin paste 3A containing diffusing material 9 and a resin material is placed on one main surface of light-transmitting body 4.

[0102] The diffusion layer 3 is formed by, for example, a printing method on the surface of the light-transmitting body 4. Although the method for forming the diffusion layer 3 is not limited to the printing method, an example of a printing method will be described below. A resin paste 3A containing a diffusing material 9, a resin material, and a solvent is prepared, and the resin paste 3A is applied to the surface (principal surface) of the light-transmitting body 4. As the resin material, an organic resin such as a silicone resin, an epoxy resin, a phenol resin, or a polyimide resin can be used. The resin paste 3A may also contain a filler as necessary. The application of the resin paste 3A may be performed, for example, by supplying the resin paste 3A onto a screen plate placed on the light-transmitting body 4, and then moving a squeegee so that the resin paste 3A passes through the screen plate, and applying the resin paste 3A to a predetermined thickness onto the light-transmitting body 4. This allows the resin paste 3A to be applied to a uniform thickness. Thereafter, the resin material of the resin paste 3A is cured to obtain the diffusion layer 3. The resin material is cured by an appropriate method such as drying, heating, or ultraviolet irradiation depending on the type of the resin material.

[0103] In addition, before the resin paste 3A is cured, as shown in FIG. 4, the resin paste 3A may be applied to one main surface of the light-transmitting body 4, and then the main surface of the light-transmitting body 4 on which the resin paste 3A is applied may be turned downward as shown in FIG. 5(a). That is, the light-transmitting body 4 may be inverted so that the two main surfaces of the light-transmitting body 4 are switched upside down. Then, as shown in FIG. 5(b), the diffusion material 9 is allowed to settle in the resin paste 3A on the side opposite to the surface in contact with the light-transmitting body 4. As a method of settling, a natural settling method using gravity acting on the diffusion material 9 may be mentioned. This allows the concentration of the diffusion material 9 in the diffusion layer 3 formed on the main surface of the light-transmitting body 4 facing the light-emitting element 2 to be higher on the side closer to the light-emitting element 2 than on the side closer to the light-transmitting body in the direction perpendicular to the main surface. Then, in a state where a desired distribution of the diffusion material 9 is obtained in the resin paste 3A (preferably, in a state where the diffusion material 9 has completely settled), the resin material of the resin paste 3A is cured to obtain the diffusion layer 3. This makes it possible to make the light transmittance approximately the same (approximately uniform) in a direction parallel to the main surface of the light transmitting body.

[0104] The diffusion member 30 of this embodiment can be obtained by the above-mentioned method. However, the diffusion layer 3 formed on the light-transmitting body 4 by such a method may not have a desired concentration distribution of the diffusion material 9 near the periphery of the diffusion layer 3 (hereinafter referred to as the "periphery") when viewed in a plan view from a direction perpendicular to the main surface of the light-transmitting body 4 on which the diffusion layer 3 is formed. In particular, when a printing method is used to form the diffusion layer 3, the diffusion layer 3 may become thinner as it approaches the periphery as shown in FIG. 4, and the distribution state of the diffusion material 9 may differ between the portion away from the periphery and the periphery, and the particles of the diffusion material may be disposed at a position other than the desired position. In order to solve such a problem, it is preferable to further include a step of selecting an area with approximately the same distribution of the diffusion material 9 from the inner area excluding the periphery of the diffusion layer 3 (the inner area excluding the periphery of the diffusion layer 3 and the periphery of the light-transmitting body 4) along the cutting line 12 in FIG. 5(c) and cutting out the diffusion layer 3 and the light-transmitting body 4 into a predetermined shape. This cutting process makes it possible to obtain a diffusing member in which the concentration of the diffusing material 9 in the diffusion layer 3 is distributed in a direction parallel to the main surface of the light-transmitting body in a substantially uniform manner. More preferably, by adjusting the amount of the diffusing material 9 and the above-mentioned settling time, and further by selecting a portion to be cut out as the diffusing member, it is possible to make it possible to ensure that the particles of the diffusing material 9 are lined up all over the space from the side of the diffusion layer exposed by the cutting process to the side opposite that side, as shown in Fig. 1.

[0105] (Modification of the manufacturing method of the diffusion member 30) Fig. 6 is a schematic plan view showing a modified example of the method for manufacturing the diffusing member 30. The method shown in Fig. 6 makes it possible to more efficiently manufacture many diffusing members 30. Note that the manufacturing conditions described above may be used unless otherwise specified. Resin paste 3A is applied to one main surface of the light-transmitting body 4. Next, the main surface of the light-transmitting body 4 on which the resin paste 3A is applied may be turned downward, and the diffusing material 9 may be deposited in the resin paste 3A on the side opposite to the surface in contact with the light-transmitting body 4. Next, the resin material of the resin paste 3A is cured to obtain the diffusing layer 3. Thereafter, a singulation step is performed in which cutting is performed along cutting lines 12 shown in FIG. 6, thereby making it possible to obtain a plurality of diffusion members 30 having a predetermined shape.

[0106] In the singulation process, it is preferable to cut out each diffusion member 30 (diffusion layer 3 and light-transmitting body 4) from an inner region excluding peripheral portion 13 of diffusion layer 3 so that peripheral portion 13 of diffusion layer 3 is not included in the diffusion member 30 after singulation, and singulate the diffusion member 30 into a predetermined shape. Moreover, by selecting diffusion members 30 having substantially the same distribution of diffusion material in the diffusion layer from among the plurality of cut diffusion members 30 and manufacturing a plurality of light-emitting devices 100 using the selected diffusion members 30, it is also possible to uniform the optical characteristics of each of these light-emitting devices 100.

[0107] (Method of manufacturing the light emitting device 100) A method for manufacturing the light emitting device 100 using the diffusion member 30 thus obtained will be described below. The method for manufacturing the light emitting device 100 includes the steps of preparing the light emitting element 2 and arranging the diffusing member 30 on the light emitting element 2.

[0108] The step of preparing the light emitting element 2 is performed, for example, by flip-chip mounting the light emitting element 2 and, if necessary, the semiconductor element 8 on a substrate 1 on which wiring 11 is formed, the wiring 11 being insulated and separated into a positive electrode and a negative electrode.

[0109] In the step of disposing the diffusion member 30 on the light emitting element 2, for example, the diffusion member 30 is bonded to the upper surface (light emitting surface 23) of the light emitting element 2 via an adhesive layer 5. The adhesive layer 5 bonds the diffusion layer 3 to the light emitting element 2. Furthermore, the diffusion layer 3 may be formed to be larger than the area of ​​the upper surface (light emitting surface 23) of the light emitting element 2. In this case, the diffusion layer 3 is bonded to the light emitting element 2 with an exposed portion that is not covered by the upper surface of the light emitting element. Therefore, when disposing the diffusion layer 3 on the upper surface of the light emitting element 2, the adhesive that protrudes from the upper surface of the light emitting element 2 adheres to the side surface of the light emitting element 2 and the exposed portion of the diffusion layer, forming a protruding portion of the adhesive layer 5 on the side surface of the light emitting element 2. The adhesive layer 5 on the side surface of the light emitting element 2 may have a triangular cross section in which the thickness of the layer decreases in the direction opposite to the diffusion layer 3 of the light emitting element 2 in a vertical cross section. As a result, the light emitted from the side surface of the light emitting element 2 is reflected at a wide range of angles by the adhesive layer 5 on the side surface, making it easier to enter the outer periphery of the diffusion layer 3, and the brightness of the light emitting device 100 can be further improved. In the manufacturing process, the adhesive before bonding can be applied to the diffusion layer 3 or can be applied to the upper surface of the light emitting element 2. In this case, it is preferable to extend a part of the adhesive to a corner formed by the side surface of the light emitting element 2 and the surface of the diffusion layer 3 facing the light emitting element 2. This is to make the part of the adhesive layer 5 protruding onto the side surface of the light emitting element 2 have a triangular cross section.

[0110] If necessary, a covering member 6 may be disposed. The covering member 6 is disposed along the side surface of the light-emitting element 2 and the side surface of the diffusion member 30. The covering member 6 is for reflecting light emitted from the light-emitting element 2. The covering member 6 may cover the entire semiconductor element 8. The gaps between the substrate 1 and the light emitting element 2 and between the semiconductor element 8 and the gaps between the conductive member 7 and another conductive member 7 may be filled with an underfill. EXAMPLES

[0111] (1) Examples 1 to 8: Green Light-Emitting Device As Examples 1 to 8, measurement samples of the light emitting device 100 shown in FIGS. 1 and 2 were prepared as follows. The light emitting element 2 and the semiconductor element 8 were placed on the substrate 1. Specifically, the light emitting element 2, which was formed by stacking a semiconductor layer on a sapphire substrate using a conductive member 7 made of Au, had a thickness of about 0.15 mm, a planar shape of a substantially square of about 1.0 mm square, and a dominant wavelength of 523 nm, and was flip-chip mounted by arranging the light emitting element 2 and the semiconductor element 8 in a line so that the sapphire substrate side was the light emitting surface. The semiconductor element 8, which had previously been provided with bumps made of Au, was flip-chip mounted on the wiring 11 of the substrate 1.

[0112] Next, the diffusion layer 3 was applied by printing to the surface of the light-transmitting body 4, i.e., the entire one of the main surfaces. The material of the light-transmitting body 4 was borosilicate glass molded into a plate shape. The planar shape of the light-transmitting body 4 was a substantially square of about 1.15 mm square, which was about 0.15 mm larger in length and width than the planar shape of the light-emitting element 2, and had a thickness of about 0.145 mm. In the light-transmitting body on which the diffusion layer 3 was formed, alumina oxide with a central particle size of 0.4 μm was used as the diffusion material, and silicone resin was used as the resin 31, which was printed on one of the main surfaces of the plate-shaped light-transmitting body 4 and cut to an appropriate size.

[0113] The concentration of the diffusing material in this diffusion layer 3 is shown in Table 1. The planar shape of the diffusion layer facing the light-emitting surface 23 of the light-emitting element 2 was a substantial square of about 1.15 mm square, the same as the planar shape of the light-transmitting body 4, and had a thickness of about 35 μm. The thickness of the light-transmitting body 4 was about 145 μm, and the total thickness of the light-transmitting body 4 and the diffusion layer 3 was about 180 μm.

[0114] Next, silicone resin was placed as an adhesive on the light-emitting surface 23 of the light-emitting element 2 to bond the diffusion layer 3 formed on the light-transmitting body 4 to the sapphire substrate of the light-emitting element 2. The area of ​​the diffusion layer 3 on the light-emitting element side was formed to be larger than the area of ​​the upper surface of the light-emitting element 2, and the diffusion layer 3 was bonded so as to have an exposed surface exposed from the bonding surface.

[0115] Next, the covering member 6 was filled around the light emitting element 2, the diffusion layer 3, the light transmitting body 4, and the semiconductor element 8. The covering member 6 was arranged along the side surfaces of the light emitting element 2, the diffusion layer 3, and the light transmitting body 4, and the semiconductor element 8 was completely buried in the covering member 6. Dimethyl silicone resin was used as the resin of the covering member 6, and titanium oxide particles with an average particle size of 0.28 μm were used as the light reflective material. The titanium oxide particles were contained in 60 mass % of the resin. The thickness of the covering member 6 was the thickness in the vertical direction from the side surface of the light emitting element 2 to the outside of the light emitting device 100, and the thickness was the same except for the thickness in the direction in which the semiconductor element 8 exists, and the thinnest part was 225 μm. By such a process, the light emitting device 100 shown in FIGS. 1 and 2 was produced.

[0116] [Chromaticity and dominant wavelength] The chromaticity and dominant wavelength of the measurement sample for the light-emitting device were measured using a light measurement system that combines a multichannel spectrometer and an integrating sphere. The evaluation results are shown in Table 1.

[0117] [Directional chromaticity] The relationship (angle dependency) between the emission color of each measurement sample and the measurement direction was also examined. In measuring the directional chromaticity (light distribution chromaticity), a current of 1000 mA was applied to the light emitting devices of each comparative example and example to emit light, and the measurement direction was changed by rotating the LED using a goniometer, and the emission color was measured using a spectral distribution measurement device under the condition of Condition B, which is the "average LED luminous intensity" measurement recommended by the CIE (International Commission on Illumination). Measurements were performed on both the Axz and Ayz measurement planes. The x and y values ​​based on the CIE color system were used to evaluate the emission color. The chromaticity x and y of the emission color at θ=0° (perpendicular line) were set to the reference values ​​x0 and y0, respectively, and chromaticity measurements were performed in the range of θ=-60° to 60° on each measurement plane.

[0118] For chromaticity x, the differences Δx1 and Δx2 between the maximum and minimum deviations (chromaticity difference Δx) from the reference value x0 were calculated, and the directional chromaticity of the light-emitting device was evaluated from their average value α. The evaluation results are shown in Table 1. As an example of the chromaticity measurement results, a graph of the directional chromaticity on the Axz plane is shown in Figure 7. For chromaticity y, the differences Δy1 and Δy2 between the maximum and minimum deviations (chromaticity difference Δy) from the reference value y0 were calculated, and the directional chromaticity of the light-emitting device was evaluated from their average value β. The evaluation results are shown in Table 2. As an example of the chromaticity measurement results, a graph of the directional chromaticity on the Axz plane is shown in Figure 8.

[0119] [Uneven lighting] Regarding uneven lighting, whether or not the shape of the electrodes of the light-emitting element was projected onto the plane illuminated with the light emitted from the measurement sample was visually confirmed. A photograph of the plane illuminated with the light emitted from the measurement sample is shown in Figure 9. Cases where uneven lighting due to the projection of the shape of the electrodes of the light-emitting element was discernible were marked with an "X", and cases where it was not discernible (there was no uneven lighting), were marked with an "O". These are shown in Tables 1 and 2.

[0120] [Table 1]

[0121] [Table 2]

[0122] (i) Samples No. 1 to 8 are evaluated based on chromaticity x. For the measurement samples No. 1 to 3, the diffusion components did not contain diffusion material (i.e., they were transparent components) or the amount of diffusion material was not appropriate, so the average value α of the differences Δx1 and Δx2 between the maximum and minimum values ​​of Δx was 0.0024 or more, resulting in uneven illumination. In the measurement samples of samples No. 4 to 8, the amount of diffusing material was appropriate, so the average value of the differences Δx1 and Δx2 between the maximum and minimum values ​​of Δx was less than 0.0024, and no illumination unevenness was confirmed.

[0123] (ii) Samples No. 1 to 8 are evaluated based on the chromaticity y. In the measurement samples No. 2 to 3, the average value β of the differences Δy1, Δy2 between the maximum and minimum values ​​of Δy was more than 30% of the average value β (=average value β') of the differences Δy1, Δy2 between the maximum and minimum values ​​of Δy in the measurement sample No. 1 (a measurement sample having a transparent member instead of a diffusing member). The measurement samples Nos. 1 to 3 had an average value β of 0.0010 or more. Moreover, the average value β of the measurement samples Nos. 1 to 3 did not satisfy the formula (1). That is, the average value β was equal to or greater than (0.0006y0+0.0006). β<0.0006y0+0.0006 (1) Furthermore, in the measurement samples Nos. 1 to 3, illumination unevenness occurred.

[0124] The average value β of the measurement specimens Nos. 4 to 8 was less than 30% of the average value β (=average value β') of the measurement specimen No. 1. The measurement samples Nos. 4 to 8 had an average value β of less than 0.0010. Moreover, the average value β of the measurement samples Nos. 4 to 8 satisfied the above formula (1). In addition, in the measurement samples of Samples No. 4 to 8, no illumination unevenness was observed.

[0125] (2) Examples 9 to 13: Blue light-emitting device A light emitting device was produced under the same conditions as Samples Nos. 1 to 7, except that Light Emitting Element 2 having a dominant wavelength of 470 nm was used, and these were used as measurement samples for Samples Nos. 9 to 15. As with Samples No. 1 to 7, the chromaticity, dominant wavelength, directional chromaticity, and illumination unevenness of the measurement samples of Samples No. 9 to 15 were measured. The measurement results of the measurement samples Nos. 9 to 15 are shown in Table 3 and FIGS.

[0126] [Table 3]

[0127] (i) Samples No. 9 to 15 are evaluated based on the chromaticity y. In the measurement samples Nos. 9 to 11, the diffusing member did not contain a diffusing material (that is, it was a transparent member) or the amount of diffusing material was not appropriate, so that uneven illumination occurred. For the measurement specimens No. 9 to 11, the average value β of the differences Δy1, Δy2 between the maximum and minimum values ​​of Δy was more than 30% of the average value β (=average value β') of the differences Δy1, Δy2 between the maximum and minimum values ​​of Δy for the measurement specimen No. 9 (a measurement specimen having a transparent member instead of a diffusing member). The measurement samples Nos. 9 to 11 had an average value β of 0.0006 or more. Moreover, the average value β of the measurement samples Nos. 9 to 11 did not satisfy the formula (1). That is, the average values ​​β' and β were equal to or greater than (0.0006y0+0.0006). β<0.0006y0+0.0006 (1)

[0128] The measurement samples Nos. 12 to 15 had an appropriate amount of diffusing material, so no uneven illumination was observed. The average value β of the measurement specimens Nos. 12 to 15 was less than 30% of the average value β (=average value β') of the measurement specimen No. 9. The measurement samples Nos. 12 to 15 had an average value β of less than 0.0006. Moreover, the average value β of the measurement samples Nos. 12 to 15 satisfied the above formula (1).

[0129] The disclosure of this specification includes the following embodiments. [Section 1] A substrate; Wiring formed on the substrate; a light-emitting element having an electrode electrically connected to the wiring; a diffusion member disposed on a light emitting surface side of the light emitting element opposite to a surface on which the electrode is formed, The dominant wavelength of the light-emitting element is within the range of 500 nm to 560 nm, a first direction is parallel to one side of the diffusion member when the diffusion member is viewed in a plan view, and a second direction is perpendicular to the first direction; a first measurement surface that passes through the center of the outline when the diffusing member is viewed in a plane, parallel to the first direction, and perpendicular to the light exit surface of the diffusing member, and a second measurement surface that passes through the center of the outline, parallel to the second direction, and perpendicular to the light exit surface of the diffusing member, the chromaticity x and chromaticity y of the emitted color of the light emitting device are measured within an angle range of -60° to 60° with respect to a perpendicular line that passes through the center of the outline and is perpendicular to the light exit surface and extends in a light emission observation direction, the average value α of the difference between the maximum and minimum values ​​of the chromaticity difference Δx of the chromaticity x measured on the first measurement surface and the difference between the maximum and minimum values ​​of the chromaticity difference Δx of the chromaticity x measured on the second measurement surface is less than 0.0024. [Section 2] A substrate; Wiring formed on the substrate; a light-emitting element having an electrode electrically connected to the wiring; a diffusion member disposed on a light emitting surface side of the light emitting element opposite to a surface on which the electrode is formed, The dominant wavelength of the light-emitting element is within the range of 420 nm to 560 nm, a first direction is parallel to one side of the diffusion member when the diffusion member is viewed in a plan view, and a second direction is perpendicular to the first direction; a first measurement surface that passes through the center of the outline when the diffusing member is viewed in a plane, parallel to the first direction, and perpendicular to the light exit surface of the diffusing member, and a second measurement surface that passes through the center of the outline, parallel to the second direction, and perpendicular to the light exit surface of the diffusing member, the chromaticity x and chromaticity y of the emitted color of the light emitting device are measured within an angle range of -60° to 60° at the center of the outline, based on a perpendicular line that passes through the center of the outline and is perpendicular to the light exit surface and extends in a light emission observation direction, the average value β of the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the first measurement surface and the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the second measurement surface is less than 30% of the average value β' obtained by measuring the emitted color of a light emitting device that has a transparent member instead of the diffusing member. [Section 3] A substrate; Wiring formed on the substrate; a light-emitting element having an electrode electrically connected to the wiring; a diffusion member disposed on a light emitting surface side of the light emitting element opposite to a surface on which the electrode is formed, The dominant wavelength of the light-emitting element is within the range of 420 nm to 560 nm, a first direction is parallel to one side of the diffusion member when the diffusion member is viewed in a plan view, and a second direction is perpendicular to the first direction; a first measurement surface that passes through the center of the outer shape when the diffusing member is viewed in a plane, is parallel to the first direction, and is perpendicular to the light exit surface of the diffusing member, and a second measurement surface that passes through the center of the outer shape, is parallel to the second direction, and is perpendicular to the light exit surface of the diffusing member, the chromaticity x and chromaticity y of the emitted color of the light emitting device are measured within an angle range of -60° to 60° at the center of the outer shape, based on a perpendicular line that passes through the center of the outer shape and is perpendicular to the light exit surface and extends in a light emission observation direction, the average value β of the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the first measurement surface and the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the second measurement surface satisfies the following formula (1): β<0.0006y0+0.0006 (1) Here, y0 is the chromaticity y of the emitted color of the light emitting device measured on the perpendicular line that passes through the center of the outer shape, is perpendicular to the light emitting surface, and extends in the light emission observation direction. [Section 4] A substrate; Wiring formed on the substrate; a light-emitting element having an electrode electrically connected to the wiring; a diffusion member disposed on a light emitting surface side of the light emitting element opposite to a surface on which the electrode is formed, The dominant wavelength of the light-emitting element is in the range of 420 nm to 480 nm, a first direction is parallel to one side of the diffusion member when the diffusion member is viewed in a plan view, and a second direction is perpendicular to the first direction; a first measurement surface that passes through the center of the outline when the diffusing member is viewed in a plane, parallel to the first direction, and perpendicular to the light exit surface of the diffusing member, and a second measurement surface that passes through the center of the outline, parallel to the second direction, and perpendicular to the light exit surface of the diffusing member, the chromaticity x and chromaticity y of the emitted color of the light emitting device are measured within an angle range of -60° to 60° at the center of the outline, based on a perpendicular line that passes through the center of the outline and is perpendicular to the light exit surface and extends in a light emission observation direction, the average value β of the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the first measurement surface and the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the second measurement surface is less than 0.0006. [Section 5] Item 2. The light emitting device according to item 1, wherein, in measurements on each of the first measurement surface and the second measurement surface, the chromaticity x ranges from 0.04 to 0.25, and the chromaticity y ranges from 0.45 to 0.77. [Section 6] Item 4. The light emitting device according to item 2 or 3, wherein the dominant wavelength of the light emitting element is within the range of 420 nm or more and 480 nm or less. [Section 7] 7. The light emitting device according to any one of items 2 to 4 and 6, wherein, in measurements on each of the first measurement surface and the second measurement surface, the chromaticity x ranges from 0.04 to 0.25, and the chromaticity y ranges from 0.01 to 0.77. [Section 8] the diffusion member includes a light-transmitting body and a diffusion layer disposed between the light-transmitting body and a light-emitting surface of the light-emitting element, The diffusion layer includes a resin and a particulate diffusion material disposed in the resin. Item 8. The light emitting device according to any one of items 1 to 7. [Section 9] a concentration of the diffusion material in the diffusion layer is within a range of 0.1% by mass to 20% by mass, with the resin being 100% by mass; 9. The light emitting device according to claim 8, wherein the particle diameter of the diffusing material is within the range of 0.1 μm to 2.0 μm. [Section 10] Item 10. The light emitting device according to item 8 or 9, wherein the diffusion material is at least one selected from the group consisting of aluminum oxide, titanium oxide, and yttrium phosphate. [Section 11] Item 11. The light emitting device according to any one of items 8 to 10, wherein the diffusion layer further contains a filler. [Section 12] Item 12. The light-emitting device according to item 11, wherein the filler is silicon oxide particles. [Section 13] A diffusion member arranged on a light emitting surface side of a light emitting element to diffuse light from the light emitting element, a first direction is parallel to one side of the diffusion member when the diffusion member is viewed in a plan view, and a second direction is perpendicular to the first direction; The diffusing member is disposed on the light emitting surface of a light emitting element having a dominant wavelength of 523 nm, and light from the light emitting element is passed through the diffusing member. In each of a first measurement surface that passes through the center of the outline of the diffusing member when viewed in a plane, is parallel to the first direction, and is perpendicular to the light exit surface of the diffusing member, and a second measurement surface that passes through the center of the outline, is parallel to the second direction, and is perpendicular to the light exit surface of the diffusing member, the angle at the center of the outline is determined based on a perpendicular line that passes through the center of the outline and extends in a light emission observation direction perpendicular to the light exit surface. a diffusing member, wherein, when the chromaticity x and chromaticity y of the emitted color of the light that has passed through the diffusing member are measured in a range of -60° or more and 60° or less, an average value β of the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the first measurement surface and the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the second measurement surface is less than 30% of the average value β' obtained by placing a transparent member instead of the diffusing member on the light-emitting surface of the light-emitting element and measuring the emitted color of the light from the light-emitting element that has passed through the transparent member. [Section 14] the diffusion member includes a light-transmitting body and a diffusion layer disposed between the light-transmitting body and a light-emitting surface of the light-emitting element, The diffusion layer includes a resin and a particulate diffusion material disposed in the resin. Item 14. The diffusion member according to item 13. [Section 15] a concentration of the diffusion material in the diffusion layer is within a range of 0.1% by mass to 20% by mass, with the resin being 100% by mass; Item 15. The diffusion member according to item 14, wherein the particle diameter of the diffusion material is in the range of 0.1 μm to 2.0 μm. [Section 16] Item 16. The diffusing member according to item 14 or 15, wherein the diffusing material is at least one selected from the group consisting of aluminum oxide, titanium oxide, and yttrium phosphate. [Section 17] Item 17. The diffusing member according to any one of items 14 to 16, wherein the diffusion layer further contains a filler. [Section 18] Item 18. The diffusion member according to item 17, wherein the filler is a particle of silicon oxide. [Explanation of symbols]

[0130] 1 Board 2 Light emitting element 21 Light-emitting element electrode 23 Light-emitting surface of light-emitting element 30 Diffusion material 30a First Side 30b Second Side 3. Diffusion Layer 31 Diffusion layer resin 33 Light exit surface of diffusion member 3A Resin Paste 4 Translucent body 5 Adhesive layer 6 Covering materials 7 Conductive materials 8. Semiconductor elements 9 Diffusion material 11 Wiring 12 Cutting line 13 Periphery of diffusion layer 100 Light emitting device

Claims

1. A substrate; Wiring formed on the substrate; a light-emitting element having an electrode electrically connected to the wiring; a diffusion member disposed on a light emitting surface side of the light emitting element opposite to a surface on which the electrode is formed, A light emitting device that does not include a wavelength conversion member, The dominant wavelength of the light-emitting element is in the range of 500 nm to 560 nm, a first direction is parallel to one side of the diffusion member when the diffusion member is viewed in a plan view, and a second direction is perpendicular to the first direction; a first measurement surface that passes through the center of the outer shape when the diffusing member is viewed in a plane, is parallel to the first direction, and is perpendicular to the light exit surface of the diffusing member, and a second measurement surface that passes through the center of the outer shape, is parallel to the second direction, and is perpendicular to the light exit surface of the diffusing member, the chromaticity x and chromaticity y of the emitted color of the light emitting device are measured within an angle range of -60° to 60° at the center of the outer shape, based on a perpendicular line that passes through the center of the outer shape and is perpendicular to the light exit surface and extends in a light emission observation direction, the average value α of the difference between the maximum and minimum values ​​of the chromaticity difference Δx of the chromaticity x measured on the first measurement surface and the difference between the maximum and minimum values ​​of the chromaticity difference Δx of the chromaticity x measured on the second measurement surface is less than 0.0024.

2. A substrate; Wiring formed on the substrate; a light-emitting element having an electrode electrically connected to the wiring; a diffusion member disposed on a light emitting surface side of the light emitting element opposite to a surface on which the electrode is formed, A light emitting device that does not include a wavelength conversion member, The dominant wavelength of the light-emitting element is in the range of 420 nm to 560 nm, a first direction is parallel to one side of the diffusion member when the diffusion member is viewed in a plan view, and a second direction is perpendicular to the first direction; a first measurement surface that passes through the center of the outer shape when the diffusing member is viewed in a plane, is parallel to the first direction, and is perpendicular to the light exit surface of the diffusing member, and a second measurement surface that passes through the center of the outer shape, is parallel to the second direction, and is perpendicular to the light exit surface of the diffusing member, the chromaticity x and chromaticity y of the emitted color of the light emitting device are measured within an angle range of -60° to 60° at the center of the outer shape, based on a perpendicular line that passes through the center of the outer shape and is perpendicular to the light exit surface and extends in a light emission observation direction, the average value β of the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the first measurement surface and the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the second measurement surface satisfies the following formula (1): β<0.0006y ０ +0.0006 (1) Here, y ０ is the chromaticity y of the emitted color of the light emitting device measured on the perpendicular line that passes through the center of the outline, is perpendicular to the light emitting surface, and extends in the light emission observation direction.

3. A substrate; Wiring formed on the substrate; a light-emitting element having an electrode electrically connected to the wiring; a diffusion member disposed on a light emitting surface side of the light emitting element opposite to a surface on which the electrode is formed, A light emitting device that does not include a wavelength conversion member, The dominant wavelength of the light-emitting element is in the range of 420 nm to 480 nm, a first direction is parallel to one side of the diffusion member when the diffusion member is viewed in a plan view, and a second direction is perpendicular to the first direction; a first measurement surface that passes through the center of the outer shape when the diffusing member is viewed in a plane, is parallel to the first direction, and is perpendicular to the light exit surface of the diffusing member, and a second measurement surface that passes through the center of the outer shape, is parallel to the second direction, and is perpendicular to the light exit surface of the diffusing member, the chromaticity x and chromaticity y of the emitted color of the light emitting device are measured within an angle range of -60° to 60° at the center of the outer shape, based on a perpendicular line that passes through the center of the outer shape and is perpendicular to the light exit surface and extends in a light emission observation direction, the average value β of the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the first measurement surface and the difference between the maximum and minimum values ​​of the chromaticity difference Δy of the chromaticity y measured on the second measurement surface is less than 0.0006.

4. 2 . The light emitting device according to claim 1 , wherein the chromaticity x ranges from 0.04 to 0.25 and the chromaticity y ranges from 0.45 to 0.77 in measurements on each of the first measurement surface and the second measurement surface.

5. The light emitting device according to claim 2 , wherein the dominant wavelength of the light emitting element is within a range of 420 nm to 480 nm.

6. 4. The light emitting device according to claim 2, wherein the chromaticity x ranges from 0.04 to 0.25, and the chromaticity y ranges from 0.01 to 0.77, in measurements on each of the first measurement surface and the second measurement surface.

7. the diffusion member includes a light-transmitting body and a diffusion layer disposed between the light-transmitting body and a light-emitting surface of the light-emitting element, The diffusion layer includes a resin and a particulate diffusion material disposed in the resin. The light emitting device according to any one of claims 1 to 3.

8. a concentration of the diffusion material in the diffusion layer is in the range of 0.1% by mass to 20% by mass, with the resin being 100% by mass; The light emitting device according to claim 7 , wherein the particle diameter of the diffusing material is within a range of 0.1 μm to 2.0 μm.

9. 8. The light emitting device according to claim 7, wherein the diffusing material is at least one selected from the group consisting of aluminum oxide, titanium oxide, and yttrium phosphate.

10. The light emitting device of claim 7 , wherein the diffusing layer further comprises a filler.

11. The light emitting device of claim 10, wherein the filler is particles of silicon oxide.

Images