JP2010245576A - Light emitting device and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device in which the color tone unevenness of light to emit is decreased without using a light diffusion material entirely, thereby an emission efficiency is markedly improved than that of a conventional one, and a facility space and a facility cost are alleviated, and also to provide a method of manufacturing the same. <P>SOLUTION: The light emitting device comprises laminating one or more phosphor layers 10 (11, 12) which include phosphors 20 (25, 27) which absorb light from a light emitting element 5, convert a wavelength, and emit light on a light emission surface of the light emitting element 5 to cover the light emission surface of the light emitting element 5 the main emission wavelength of which is 410 nm or less. The phosphor layers 10 (11, 12) are also made to have the difference of the maximum thickness and the minimum thickness which is less than an average particle diameter of the phosphor 20 (25, 27), and the occupancy rate of the phosphors 20 (25, 27) in the phosphor layers 10 (11, 12) is made 50% or more. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light-emitting device that emits white light used for, for example, an illumination light source, a liquid crystal backlight light source, and the like, and a manufacturing method thereof.

  In recent years, by combining a light-emitting element that emits ultraviolet light or blue light and a phosphor that absorbs light from the light-emitting element and converts the wavelength to emit long-wavelength light, a white light having a wide emission wavelength range. Light emitting devices that emit light have been developed. Such a light-emitting device is used for applications such as an illumination light source and a liquid crystal backlight light source. As this illumination light source and liquid crystal backlight light source, white light having low chromaticity unevenness and high color rendering properties is required.

  In Patent Document 1, two or more types of phosphors that perform different wavelength conversion are arranged on a light emitting element that emits blue light, and color rendering properties are achieved by mixing the light from the light emitting element and the light that has undergone wavelength conversion by each phosphor. There is disclosed a light emitting device that improves the above.

  FIG. 14 is a diagram showing a configuration of a map lamp 101 in an automobile using the light emitting device 100 described in Patent Document 1. In general, in the map lamp 101 used in an automobile, the brightness within a circle of light having a diameter of 30 to 40 cm formed on a paper surface such as a map as an irradiated object located at a position away from the light emitting device 100 by, for example, about 60 cm. The illuminance is required to be 30 lux or more. As described above, when the light emitting device 100 is used for the map lamp 101 or the like, the light from the light emitting device 100 is condensed by the optical lens 102 to make the predetermined range particularly bright.

JP 2001-127346 A

  However, when the light-emitting device 100 described in Patent Document 1 is used, the phosphor is mixed with a transparent resin to cover the light-emitting element. Therefore, the fluorescent light is thinly and uniformly around the light-emitting element due to the surface tension of the liquid mixture. The color tone unevenness has not been sufficiently solved due to the effect of the inability to arrange the body and the precipitation of the phosphor in the liquid mixture that occurs while the resin is cured, so the color tone unevenness of the light collected by the optical lens 102 is not solved. Will be increased. Furthermore, since the blue light emitted from the light emitting element has directivity, when the optical element such as a lens collects or scatters the light, the color tone unevenness of the light through the optical element becomes large. Therefore, as shown in FIG. 14, it is necessary to provide a light diffusing material 103 between the optical lens 102 and the irradiation object 105 to diffuse the collected light to reduce color unevenness and directivity. As described above, when the light diffusing material 103 is used, the light is attenuated when passing through the light diffusing material 103, so that the light emission efficiency of the light emitting device 100 is greatly reduced (about 1/3). Therefore, for example, when used for various purposes such as the map lamp 101, it is necessary to improve the luminance by using a plurality of light emitting devices 100 as shown in FIG. In addition, the color unevenness of the condensed light is caused by the uneven distribution of the light diffusing material, and it is difficult to produce a light emitting element having a uniform color temperature.

  The present invention has been made in view of the above problems, and can improve the light emission efficiency by reducing unevenness in the color tone of light emitted without using a light diffusing material, thereby reducing the facility space and the facility cost. It is an object of the present invention to provide an apparatus and a manufacturing method thereof.

  In the above light-emitting device, the phosphor layer may have a thickness not more than 5 times the average particle diameter of the phosphor.

  In the light emitting device, when forming the phosphor layer, after applying an adhesive thinner than the average particle diameter of the phosphor on the light emitting element, the phosphor is fixed to the applied adhesive. Then, a forming step of forming a phosphor constituting layer may be performed, and the phosphor constituting layer may be laminated until a desired color temperature is obtained for the phosphor layer.

  In the light emitting device, when the adhesive is applied, the surface of the application may be heated with a heater.

  In the light emitting device, two or more layers of the phosphor layer are laminated on the light emitting surface of the light emitting element, and the main emission wavelength of the phosphor contained in the phosphor layer on the side close to the light emitting element; The main absorption wavelength of the phosphor contained in the phosphor layer far from the light emitting element may be different.

  Further, according to the present invention, the light emitting device having a main emission wavelength of 410 nm or less, and a phosphor layer containing a phosphor that absorbs light from the light emitting device and converts the wavelength to emit light, the maximum The phosphor layer having a difference between the thickness and the minimum thickness being not more than twice the average particle size of the phosphor is directly formed on the light emitting surface of the light emitting element so as to cover the light emitting surface of the light emitting element. The phosphor layer is composed of a plurality of phosphor constituent layers, and the phosphor occupying ratio in the phosphor constituent layer farthest from the light emitting element is 50% or less. There is provided a method for manufacturing a light emitting device, characterized in that the phosphor constituting layer is formed so that an occupation ratio of the phosphor in other phosphor constituting layers is 60% or more.

  In the method for manufacturing a light emitting device, the thickness of the phosphor layer may be less than or equal to five times the average particle diameter of the phosphor.

  In the method for manufacturing a light emitting device, when the phosphor layer is formed, an adhesive is applied thinner than the average particle diameter of the phosphor on the light emitting element, and then the fluorescent material is applied to the applied adhesive. You may make it form the said fluorescent substance layer by performing the formation process which arrange | positions a body and forms a fluorescent substance structure layer once or repeatedly several times.

  In the method for manufacturing a light emitting device, the adhesive may be applied in a state where the viscosity of the adhesive is lowered.

  In the method for manufacturing a light emitting device, when laminating the one or more phosphor layers, the main emission wavelength of the phosphor contained in the phosphor layer near the light emitting element is far from the light emitting element. You may make it laminate | stack so that it may differ from the main absorption wavelength of the fluorescent substance contained in the fluorescent substance layer of the side.

  In the method for manufacturing a light emitting device, in the case of laminating the plurality of phosphor constituent layers, the application of the adhesive, the fixation of the phosphor, the temporary curing of the adhesive, the measurement of the color temperature, and the measurement A desired color temperature may be obtained by repeating the verification of the result.

  According to the present invention, by using a light emitting element whose main emission wavelength is 410 nm or less outside the visible light region, the directivity of visible light emitted from the light emitting device is reduced, and the phosphor layer has a thickness of phosphor. By adhering to an adhesive having an average particle size of or less, the phosphor can be uniformly distributed in the phosphor layer, and color tone unevenness can be further reduced.

1 is an overall configuration diagram of a light emitting device 1 according to a first embodiment of the present invention. It is the enlarged view which expanded and showed the light emitting element 5 which the light-emitting device 1 shown in FIG. 1 has. It is the enlarged view which expanded and showed the fluorescent substance layers 10-12 formed on the light emitting element 5 shown in FIG. It is a whole flowchart which shows the procedure of the manufacturing method which concerns on embodiment of this invention. It is a flowchart explaining the procedure of step 3 of FIG. FIG. 6 is an explanatory diagram showing a procedure when applying an adhesive 21 onto the light emitting element 5 in Step 11 of FIG. 5. FIG. 6 is an explanatory diagram showing a procedure showing a state after applying an adhesive 21 on the light emitting element 5 in Step 11 of FIG. 5. It is explanatory drawing which shows the procedure at the time of using compressed gas as an example at the time of spraying the fluorescent substance 20 on the apply | coated adhesive agent 21. FIG. It is a block diagram of the color tone nonuniformity measuring apparatus 70 which measures the color tone nonuniformity of a light-emitting device. It is explanatory drawing which shows the procedure which laminates | stacks the fluorescent substance structure layer 10b on the fluorescent substance structure layer 10a. It is explanatory drawing which shows the procedure which laminates | stacks the fluorescent substance structure layer 10b on the fluorescent substance structure layer 10a. It is explanatory drawing which shows the procedure which laminates | stacks the fluorescent substance structure layer 10b on the fluorescent substance structure layer 10a. It is explanatory drawing which shows the procedure at the time of using an electrostatic adsorption as an example at the time of arrange | positioning the fluorescent substance 20 to the apply | coated adhesive agent 21. FIG. It is a block diagram of the map lamp 101 using the conventionally well-known light-emitting device 100. FIG. The measurement result (without lens) of the luminance ratio and correlated color temperature of the light emitting device 1 shown in FIG. 2 is expressed in coordinates where the horizontal axis is the angle (°) of the light emitting device 1 and the vertical axis is the correlated color temperature (K). It is the figure shown by plotting. The measurement result of the luminance ratio and correlated color temperature (with a lens) of the light emitting device 1 shown in FIG. 2 is expressed in coordinates where the horizontal axis is the angle (°) of the light emitting device 1 and the vertical axis is the correlated color temperature (K). It is the figure shown by plotting. Each measurement result (without a lens) of FIG. 15 is shown. Each measurement result (with a lens) of FIG. 16 is shown. It is a block diagram of the light-emitting device 200 which is the comparative example 1. FIG. The measurement result (without lens) of the luminance ratio and correlated color temperature of the light emitting device 200 which is Comparative Example 1 shown in FIG. 19, the horizontal axis is the angle (°) of the light emitting device 1, and the vertical axis is the correlated color temperature (K). It is the figure plotted by the coordinate which is). The measurement result (with lens) of the luminance ratio and correlated color temperature of the light emitting device 200 which is Comparative Example 1 shown in FIG. 19 is the angle (°) of the light emitting device 1 on the horizontal axis and the correlated color temperature (K) on the vertical axis. It is the figure plotted by the coordinate which is). Each measurement result (without a lens) of FIG. 20 is shown. Each measurement result (with a lens) of FIG. 21 is shown. FIG. 10 is a configuration diagram of a light emitting device 201 that is Comparative Example 2. FIG. 24 shows a measurement result (without a lens) of the luminance ratio and correlated color temperature of the light emitting device 201 which is Comparative Example 2, the horizontal axis is the angle (°) of the light emitting device 1, and the vertical axis is the correlated color temperature (K). It is the figure plotted by the coordinate which is). FIG. 24 shows a measurement result (with a lens) of the luminance ratio and correlated color temperature of the light emitting device 201 which is Comparative Example 2 shown in FIG. It is the figure plotted by the coordinate which is). Each measurement result (without a lens) of FIG. 25 is shown. Each measurement result (with a lens) of FIG. 26 is shown. It is a block diagram of the light-emitting device 202 which is the comparative example 3. The measurement result (without lens) of the luminance ratio and correlated color temperature of the light emitting device 202, which is Comparative Example 3 shown in FIG. 29, the horizontal axis is the angle (°) of the light emitting device 1, and the vertical axis is the correlated color temperature (K). It is the figure plotted by the coordinate which is). 29 shows the measurement result (with a lens) of the luminance ratio and correlated color temperature of the light emitting device 202 as Comparative Example 3 shown in FIG. 29, the horizontal axis is the angle (°) of the light emitting device 1, and the vertical axis is the correlated color temperature (K). It is the figure plotted by the coordinate which is). Each measurement result (without a lens) of FIG. 30 is shown. Each measurement result (with a lens) of FIG. 31 is shown.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is an overall configuration diagram of a light emitting device 1 according to a first embodiment of the present invention. FIG. 2 is an enlarged view showing the light emitting element 5 included in the light emitting device 1 shown in FIG. FIG. 3 is an enlarged view showing the phosphor layer 10, the phosphor layer 11, and the phosphor layer 12 formed on the light emitting element 5 shown in FIG. 2 in an enlarged manner.

  As shown in FIG. 1, a light emitting device 1 according to an embodiment of the present invention has a configuration in which, for example, an LED that emits ultraviolet light having a main emission wavelength of 410 nm or less is mounted as a light emitting element 5 on a flat substrate 2. Have The light-emitting element 5 is formed in a 1-mm square and 150-μm-high die shape. On the substrate 2, a side wall 3 that is annularly disposed so as to surround the periphery of the light emitting element 5 is provided. The substrate 2 is provided with an external electrode 6 to which electric power is supplied from an external power source (not shown). The external electrode 6 is connected to the light emitting element 5 by a conductive wire 7. In the present embodiment, the light emitting element 5 is configured to emit light having a main light emission wavelength of 400 to 405 nm and an optical output of 300 to 350 mW when electric power of 350 mA DC is supplied from the external electrode 6. ing.

  As shown in FIGS. 1 and 2, on the light emitting element 5, three types of phosphor layers 10, 11, and 12 have a thickness of, for example, 20 μm or more and 50 μm or less so as to cover the upper surface and the side surface that are the light emitting surfaces. It is provided in order by thickness. The term “light emitting surface” means a light emitting surface of the light emitting element 5 that serves as a light source that emits light around the light emitting device 1. In the case of the light emitting element 5 shown in FIG. Since it is arrange | positioned on the upper surface, the upper surface and side surface except a bottom face become a light emission surface. Further, the expression “covering the light emitting surface” of the light emitting element 5 using the fluorescent layer 10 or the like is used to mean that the light path of the light emitted from the light emitting element 5 is blocked. Since it is provided on the substrate 2, the upper surface and the side surface except the bottom surface of the light emitting element 5 are light emitting surfaces. In the present embodiment, the light emitting surface of the light emitting element 5 is covered by laminating one or more phosphor layers 10, 11, 12 directly on the light emitting surface of the light emitting element 5.

  In a recess formed by the annularly arranged side wall 3 and the substrate 2, for example, a sealing member 15 such as a transparent resin is filled from above the phosphor layers 10, 11, 12 to seal the light emitting element 5. ing. As shown in FIG. 3, the phosphor layer 10 has a configuration in which three phosphor constituting layers 10 a to 10 c are laminated on the light emitting element 5 in order from the bottom. The phosphor layer 11 has a configuration in which three phosphor constituting layers 11a to 11c are sequentially laminated from the bottom on the phosphor layer 10 (that is, the phosphor constituting layer 10c). Further, the phosphor layer 12 has a configuration in which three phosphor constituting layers 12a to 12c are laminated in order from the bottom on the phosphor layer 11 (that is, the phosphor constituting layer 11c).

  At this time, the difference between the maximum thickness and the minimum thickness of the phosphor layer 10 is set to be not more than twice the average particle diameter of the phosphor 20 contained in the phosphor layer 10. Similarly, the difference between the maximum thickness and the minimum thickness of the phosphor 11 is set to be not more than twice the average particle diameter of the phosphor 25 contained in the phosphor 11. The difference between the maximum thickness and the minimum thickness is set to be not more than twice the average particle diameter of the phosphor 27 contained in the phosphor 12. In the present specification, when measuring the average particle diameter of the phosphors 20, 25, 27, the phosphor layer of the light emitting device 1 is cut, and the cut surface is photographed with a scanning electron microscope (SEM). Calculated from the SEM photograph obtained by measuring the longest value of the diameters of one of the phosphors 20, 25, and 27, and calculating the average value of the particles having the longest particle diameter of 1 μm or more. Yes.

  The phosphor constituting layer 10 a is formed by fixing a phosphor 20 having an average particle diameter of, for example, 7 μm with an adhesive 21 applied to a thickness of, for example, 5 μm, which is thinner than the average particle diameter of the phosphor 20. The occupation ratio of the phosphor 20 in the phosphor constituting layer 10a is set to be 60% or more. Here, the term “occupancy” will be described. The term “occupancy ratio” used in this specification refers to the phosphor included in the cut surface with respect to the entire area of the cut surface obtained by cutting the phosphor layer or the phosphor constituting layer of the light emitting device 1. Means the proportion of the area occupied by. Note that the measurement of the phosphor occupancy in the phosphor layer or the phosphor constituent layer is also based on a photograph of the light emitting device 1 cut as in the case of measuring the average particle diameter of the phosphor as described above. Is calculated. The occupancy ratio of the phosphor layer calculated in this way is improved as the ratio of the phosphor volume in the entire volume of the phosphor layer (that is, the filling ratio) increases.

  The phosphor constituting layers 10b and 10c are configured in the same manner as the phosphor constituting layer 10a. The filling rate of the phosphor 20 contained in each phosphor constituting layer 10a to 10c is high, that is, the occupation ratio occupied by the phosphor in each phosphor constituting layer cross section is set to 60% or more. Therefore, the occupation ratio of the phosphor 20 in the phosphor layer 10 is 60% or more. Similarly to the phosphor constituting layer 10a, the phosphor constituting layer 11a is different from the phosphor 20 in that the phosphor 25 having an average particle diameter of, for example, 10 μm is larger than the average particle diameter of the phosphor 25. It is formed by being fixed by a thin adhesive 26 applied to a thickness of, for example, 5 μm. The phosphor constituting layers 11b and 11c are configured in the same manner as the phosphor constituting layer 11a. Since the occupancy ratio of the phosphor 25 contained in each of the phosphor constituent layers 11a to 11c is set to 60% or more, the occupancy ratio of the phosphor 25 in the phosphor 11 is 60% or more. ing. Further, in the same manner as the phosphor constituting layers 10a and 11a, the phosphor constituting layer 12a is different from the phosphors 20 and 25, and the phosphor 27 having an average particle diameter of 18 μm, for example, is an average of the phosphor 27. It is formed by being fixed by an adhesive 28 applied to a thickness of, for example, 5 μm, which is smaller than the particle size. The phosphor constituting layers 12b and 12c are configured in the same manner as the phosphor constituting layer 12a. Since the occupancy ratio of the phosphor 27 contained in each of the phosphor constituent layers 12a to 12c is set to 60% or more, the occupancy ratio of the phosphor 27 in the phosphor 12 is 60% or more. ing.

In the present embodiment, the phosphor 20 is represented by CaAlSiN ₃ : Eu having an average particle diameter of 7 μm, which absorbs ultraviolet light emitted from the light-emitting element 5 and emits red light having a wavelength of main emission of 659 nm by wavelength conversion. A phosphor is used. The phosphor 25 absorbs ultraviolet light emitted from the light-emitting element 5 and emits green light having a main emission wavelength of 557 nm by wavelength conversion. SrAl _{1 + x} Si _4-x O _x N ₇ having an average particle diameter of 10 μm. _-X : A phosphor represented by Ce is used. Further, as the phosphor 27, SrAl _x Si _6-x O _{1 + x} N ₈ having an average particle diameter of 18 μm that absorbs ultraviolet light emitted from the light emitting element 5 and emits blue light having a main emission wavelength of 451 nm by wavelength conversion. _-X : A phosphor represented by Eu is used.

  In this embodiment, when two or more kinds of phosphors (three kinds of phosphors 20, 25, and 27 in this embodiment) are arranged as described above, the side closer to the light emitting element 5 (that is, the inner side) is arranged. The main emission wavelength of the phosphor contained in the phosphor layer is set to be longer than the main absorption wavelength of the phosphor contained in the phosphor layer on the side far from the light emitting element 5 (that is, outside). is doing. In this specification, the main wavelength of the light that is absorbed when the phosphor performs wavelength conversion is referred to as “main absorption wavelength”, and the main wavelength of the light emitted by converting the wavelength of the light absorbed by the phosphor is referred to as “main absorption wavelength”. This is called “main emission wavelength”.

  More specifically, with respect to the phosphor layer 10 disposed closer to the light emitting element 5 than the phosphor layers 11 and 12, the main emission wavelength of the phosphor 20 contained in the phosphor layer 10 is fluorescent. This is different from the main absorption wavelengths of the phosphors 25 and 27 contained in the phosphor layers 11 and 12 disposed on the side farther from the light emitting element 5 than the body layer 10. Further, regarding the relationship between the phosphor layer 11 and the phosphor layer 12, the main emission wavelength of the phosphor 25 contained in the phosphor layer 11 disposed closer to the light emitting element 5 than the phosphor layer 12 is This is different from the main absorption wavelength of the phosphor 27 contained in the phosphor layer 12 disposed on the side farther from the light emitting element 5 than the phosphor layer 11.

  In the arrangement configuration of the phosphor layers 10 to 12 as described above, red light emitted from the phosphor 20 of the phosphor layer 10 that is relatively close to the light emitting element 5 is emitted from the phosphor layer 11 that is relatively far from the light emitting element 5. Since each of the 12 phosphors 25 and 27 is different from the main wavelength region (energy region) that absorbs to emit green and blue light, red light from the phosphor 20 in the lower layer is converted into the phosphor 25 in the upper layer, There is no fear of being wavelength-converted by being absorbed by 27. Similarly, the green light emitted from the phosphor 25 arranged in the phosphor layer 11 closer to the light emitting element 5 is emitted from the fluorescent light arranged in the phosphor layer 12 farther from the light emitting element 5. Since the body 27 is different from the main wavelength region (energy region) that absorbs to emit blue light, the green light from the phosphor 25 in the lower layer may be absorbed by the phosphor 27 in the upper layer and wavelength-converted. Absent. In this way, a phosphor that emits light having a longer wavelength is disposed on the side closer to the light emitting element 5 (ie, the inner side), and a phosphor that absorbs light having a shorter wavelength on the side farther from the light emitting element 5 (ie, the outer side). By disposing the light emitting device, it is possible to prevent a decrease in light emission output caused by multiple wavelength conversions by two or more kinds of phosphors 20, 25, and 27, and to emit a light emitting device when creating a plurality of phosphor layers. The color temperature of light can be easily adjusted.

  Next, the manufacturing method which concerns on embodiment of this invention which manufactures the light-emitting device 1 comprised as mentioned above is demonstrated using FIGS. 1-3. FIG. 4 is an overall flowchart showing the procedure of the manufacturing method according to the embodiment of the present invention.

  As shown in FIG. 4, when the manufacture of the light emitting device 1 is started (step 0), first, the light emitting element 5 is placed on the substrate 2 using, for example, solder or conductive paste (step 1). Next, the conductive wire 7 is connected to the light emitting element 5 and the external electrode 6 by using a method such as ultrasonic bonding and pressure bonding (step 2). Thereafter, the layers including the phosphor layers 10, 11, and 12 are formed on the light emitting element 5 in a predetermined order so as to cover the light emitting surface on the light emitting element 5 (step 3). In the present embodiment, as shown in FIG. 1, three different phosphor layers 10, 11, and 12 are sequentially stacked on the light emitting element 5. After the formation of the phosphor layers 10, 11, 12 is finished, a sealing member 15 such as a transparent resin is placed on the phosphor layer 12 in the recess formed by the annularly arranged side wall 3 and the substrate 2. The light emitting element 5 is sealed together with the phosphor layers 10, 11, and 12 (step 4). The manufacturing of the light emitting device 1 is completed by the above steps 0 to 4 (step 5).

  Next, the procedure for forming the phosphor layers 10, 11, and 12 when forming each layer in Step 3 will be described in detail. In the present embodiment, three phosphor layers 10, 11, and 12 are sequentially formed on the light emitting surface of the light emitting element 5. FIG. 5 is a flowchart for explaining the procedure for forming the phosphor layers 10, 11, 12 in Step 3. Hereinafter, the phosphor layer 10 formed directly on the light emitting element 5 will be described as an example.

  When the formation of the phosphor layer 10 is started (step 10), an adhesive 21 such as silicon or epoxy is applied on the light emitting element 5 which is the surface to be laminated by a method such as dispensing or spraying (for example). Step 11). FIGS. 6 and 7 are explanatory views showing a procedure when the adhesive 21 is applied onto the light emitting element 5 by the dispensing method in the above step 10.

  When applying the adhesive 21, as shown in FIG. 6, an upper surface which is a light emitting surface of the light emitting element 5 to which the adhesive 21 is applied by the heater 30 disposed below the light emitting element 5 and the substrate 2. And the sides are heated. The adhesive 21 discharged from the needle-shaped discharge port 31 is heated on the light emitting surface heated in this way, and the viscosity thereof is lowered. As shown in FIG. It is reduced and distributed with a uniform thickness on the light emitting surface of the light emitting element 5. Thereby, it can prevent that the adhesive agent 21 rises by the surface tension on the light emission surface of the light emitting element 5, and becomes non-uniform | heterogenous thickness. By doing so, the thickness of the adhesive 21 applied on the surface to be laminated becomes equal to or less than the average particle diameter of the phosphor 20 sprayed on the adhesive 21 in step 12 described later.

  In step 11 described above, in a state where the adhesive 21 applied on the light emitting surface of the light emitting element 5 is sticky, the phosphor 20 is sprayed on the applied adhesive 21 (step 12), and the light emitting element 5 emits light. The phosphor 20 is disposed on the entire surface. FIG. 8 is an explanatory diagram showing a procedure when compressed gas is used as an example of spraying the phosphor 20 onto the applied adhesive 21.

  As shown in FIG. 8, a nozzle 35 that blows the phosphor 20 is disposed at an upper position facing the light emitting surface of the light emitting element 5. A cartridge 36 for supplying the phosphor 20 to be sprayed is connected to the nozzle 35 via a pipe 37. Further, the nozzle 35 is connected via a pipe 41 to a reservoir 40 in which, for example, air, nitrogen or argon is stored as a compressed gas. The piping 41 is provided with a pressure adjusting device 42 and an on-off valve 43 that adjust the flow rate of the compressed gas from the storage unit 40. As a result, the phosphor 20 supplied from the cartridge 36 is ejected from the nozzle 35 by the compressed gas whose injection amount is adjusted by the pressure adjusting device 42 and the on-off valve 43, and is applied onto the light emitting surface of the light emitting element 5. It can be sprayed onto the agent 21.

  In the present embodiment, the nozzle 35 is provided with a sieve (not shown), and only the phosphor 20 having a particle size of a predetermined value or less can be ejected from the nozzle 35. Thereby, the particle size of the phosphor 20 sprayed on the adhesive 21 applied from the nozzle 35 is adjusted.

  The adhesive 21 in which the phosphor 20 is disposed is heated at, for example, 200 ° C. for 1 minute to be temporarily cured (step 13). The phosphor constituting layer 10 a is formed on the light emitting surface of the light emitting element 5 by the procedure of Steps 11 to 13.

  In order to determine whether or not desired light emission is obtained by the phosphor constituting layer 10a formed on the light emitting surface of the light emitting element 5, the color temperature of the light emitting device 1 is measured (step 14). FIG. 9 is an explanatory diagram of the color tone unevenness measuring apparatus 70 showing an example of a method for measuring the color temperature of the light emitting device 1. As shown in FIG. 9, a detector 46 that detects light is disposed at a position facing the light emitting device 1. In the present embodiment, the distance between the light emitting device 1 and the detector 46 is set to 1.5 m. The detector 46 is connected to the spectroscope 48 by an optical fiber 47. The external electrodes 6 of the light emitting device 1 to be measured are connected to the wirings 49 from the positive and negative electrodes of the power supply 50 and supplied with electric power, and the measurement is performed with the light emitting device 1 emitting light.

  The measurement of the color temperature is performed while rotating the light emitting device 1 as the measurement object from the position shown in FIG. 9 to the left and right within the same vertical plane (the paper surface of FIG. 9). As shown in FIG. 9, when the position of the light emitting device 1 that can measure the light irradiated in the direction perpendicular to the upper surface of the substrate 2 is an angle of 90 °, the light emitting device 1 is rotated 90 degrees to the right. The position is 0 °, and the position when rotated 90 degrees to the left is 180 °. In general, the luminance of the light emitting device is small at a position of 0 °, increases as it approaches 0 ° to 90 °, and decreases as it approaches 90 ° to 180 °.

  The light detected by the detector 46 is sent from the optical fiber 47 to the spectroscope 48. In the spectroscope 48, the spectrum of the light detected by the detector 46 is analyzed, and the luminance and correlated color temperature of the light emitting device 1 are measured based on the analysis result.

  When the desired light emission is obtained for the light emitting device 1 on which the phosphor layer 10 is formed based on the measurement result of Step 14 (Yes in Step 15), the formation of the phosphor layer 10 is completed (Step 16). . On the other hand, when desired light emission cannot be obtained (No in Step 15), the process returns to Step 11 and Steps 11 to 13 are repeated to stack a new phosphor constituting layer 10b. FIGS. 10-12 is explanatory drawing which shows the procedure which laminates | stacks the new fluorescent substance structure layer 10b. More specifically, the phosphor constituting layer 10a shown in FIG. 10 formed on the light emitting surface of the light emitting element 5 is used as a laminated surface, and as shown in FIG. 11, an adhesive 21 is formed on the phosphor constituting layer 10a. Apply. Then, as shown in FIG. 12, the phosphor 20 is sprayed and disposed on the adhesive 21 applied onto the phosphor constituting layer 10a, and then the adhesive 21 is temporarily cured, thereby forming a new phosphor structure. Layer 10b is formed.

  The color temperature of the light emitting device 1 is measured in order to determine whether or not desired light emission is obtained for the light emitting device 1 by the phosphor constituent layers 10a and 10b laminated by repeating the above steps 11 to 13 (step 14). ) When desired light emission is obtained from the measurement result (Yes in Step 15), the formation of the phosphor layer 10 is completed (Step 16). On the other hand, when desired light emission is not obtained (No of step 15), it returns to the said step 11 and repeats the said steps 11-13. As described above, the steps 11 to 15 as the formation process for forming the phosphor constituting layer are repeated until the desired light emission is obtained with respect to the light emitting device 1, and the phosphor constituting layers 10a, 10b,. To complete the formation of the phosphor layer 10 (step 16). In the present embodiment, as shown in FIG. 3, desired light emission is obtained for the phosphor layer 10 by forming the phosphor layer 10 in which the three phosphor constituent layers 10 a to 10 c are stacked. Thus, by laminating | stacking fluorescent substance structure layer 10a-10c, the fluorescent substance layer 10 can be formed very thinly, and the difference of the maximum thickness of fluorescent substance layer 10 and minimum thickness is the average of fluorescent substance 20. It becomes possible to make it 2 times or less of the particle diameter. At this time, it is preferable that the average thickness of the phosphor layer 10 is not more than 5 times the average particle diameter of the phosphor 20 contained.

  In the present embodiment, by setting all the occupancy ratios of the phosphors 20 in the phosphor constituent layers (10a, 10b,...) To 60% or more, the phosphor constituent layers (10a, 10b,. The occupancy rate of the phosphor 20 in the phosphor layer 10 constituted by (.) Is set to 60% or more. In addition, when adjusting the color temperature of the light emitting device 1, by adjusting the occupancy of the phosphor 20 in the phosphor constituent layer that is farthest from the light emitting element 5 and is finally formed to 50% or less, Fine adjustment of the color temperature is possible. For example, the case of the phosphor layer 10 formed of four phosphor constituent layers 10 a to 10 d (10 d is not shown) will be described. Three phosphor constituent layers stacked closer to the light emitting element 5. The occupation ratio of the phosphor 20 in 10a to 10c is set to 60% or more, and the occupation ratio of the phosphor 20 in the phosphor constituting layer 10d finally formed on these three layers (10a to 10c) is 5 By setting to%, the color temperature can be changed in units of 100K. At this time, the occupation ratio of the phosphor 20 in the phosphor layer 10 is about 50%.

  As described above, a phosphor layer with a high phosphor filling ratio and an occupation ratio of 50% or more can be created, and the phosphor layer can be formed very thin. Specifically, the target color temperature can be set even if the thickness of the phosphor layer is 5 times or less of the average particle diameter. Thereby, the difference (thickness unevenness) between the maximum thickness and the minimum thickness of the phosphor layer can be kept small. Furthermore, the distribution of the phosphor 20 in the phosphor layer 10 can be made more uniform. In particular, it is more effective to suppress the difference between the maximum thickness and the minimum thickness in the phosphor layer 10 to twice or less the average particle diameter of the phosphor 20. By suppressing unevenness in the thickness of the phosphor layer and making the phosphor distribution uniform, the light from the light emitting element 5 irradiated to the phosphor layer 10 from the light emitting element 5 is wavelength-converted uniformly in each light emitting direction. Therefore, it is possible to provide a light emitting device 1 that emits light with reduced color tone unevenness and improved color rendering, and a method for manufacturing the same.

  In the above description, the case of the phosphor layer 10 formed by being directly laminated on the light emitting surface of the light emitting element 5 has been described. However, after the phosphor layer 10 is formed, the phosphor layer 10 is The same procedure is used when the phosphor layers 11 and 12 are sequentially laminated on the phosphor layer 10 as the surface to be laminated. In the present embodiment, the adhesive 26 used when forming the phosphor layer 11 and the adhesive 28 used when forming the phosphor layer 12 are the adhesive used when forming the phosphor layer 10. Although the same adhesive as 21 is used, a different adhesive may be used.

  According to the above embodiment, by using the light emitting element 5 whose main emission wavelength is 410 nm or less outside the visible light region, color tone unevenness is determined by the human naked eye out of the light emitted from the light emitting device 1. As for visible light, the phosphor in the phosphor layers 10, 11, and 12 is composed of only low-directed light emission that has been subjected to wavelength conversion by absorbing light from the light-emitting element 5, and thus is emitted from the light-emitting device. The directivity of visible light can be reduced. Due to the above advantages, it is not necessary to adjust light color unevenness and directivity using a light diffusing material as in a conventionally known light emitting device, and light attenuation due to the light diffusing material does not occur. In particular, it is not necessary to use a light diffusing material even when uneven color tone becomes noticeable by condensing light from the light emitting device 1 with a lens. Thereby, the luminous efficiency of the light-emitting device can be remarkably improved as compared with the prior art, and the desired illuminance can be achieved with a smaller number of light-emitting devices 1 than in the past, and the equipment space and equipment costs can be reduced. .

  Further, the phosphor layer 10 (same for the phosphor layers 11, 12, etc.) laminated on the light emitting surface of the light emitting element 5 is disposed on the adhesive 21 having an average particle size of the phosphor 20 or less. By adopting a configuration in which one or more phosphor constituent layers 10a, 10b, and 10c are laminated, the phosphor 20 is uniformly distributed in the phosphor layer 10 and the phosphor 20 in the phosphor layer 10 is made high. The density can be filled, and the color tone unevenness can be effectively reduced.

  Furthermore, the present inventors laminated one or more phosphor layers 10, 11, 12 directly on the light emitting surface of the light emitting element 5, thereby reducing the distance that ultraviolet light from the light emitting element 5 passes through the resin. It has been found that light absorption by the resin can be reduced by reducing the size, and light emission intensity can be increased by suppressing light attenuation. In particular, by adopting a structure in which the resin layer does not exist thickly between the light emitting element and the phosphor, it is possible to prevent color tone unevenness caused by the difference in attenuation in the light emission direction of ultraviolet light due to the resin thickness unevenness. .

  For example, it is possible to prevent uneven color tone due to a difference in attenuation in the emission direction of ultraviolet light caused by uneven thickness of the resin that occurs when phosphors are mixed and dispersed in a resin or the like as in the prior art. In other words, by shortening the distance that ultraviolet rays pass through the resin, quickly converting to visible light with low light absorption by the resin and allowing it to pass through the resin, the color tone unevenness of the light emitted from the light emitting device is reduced, and the light emission output Can also be improved. For this reason, when condensing light using an optical element, it is not necessary to adjust light color unevenness and directivity using a light diffusing material as in a conventionally known light emitting device, and light attenuation by the light diffusing material. It is not necessary to generate. Specifically, when the half-value angle is 40 °, the color tone unevenness expressed by chromaticity is changed from the conventional 800K to about 100K, and when the half-value angle is 30 °, the color tone unevenness is changed from the conventional 1000K to about 150K. Furthermore, when the half-value angle is 20 °, the color tone unevenness can be reduced from the conventional 1500K to about 200K.

  Further, in the arrangement configuration of the phosphor layers 10, 11, 12 laminated on the light emitting surface of the light emitting element 5, the phosphor contained in the phosphor layer on the side close to the light emitting element 5 (that is, the inner side). The main emission wavelength of the phosphor layer is different from the main absorption wavelength of the phosphor contained in the phosphor layer on the side far from the light emitting element 5 (that is, the outer side). Since the light of the layers is not absorbed and only the light emitted from the light emitting element 5 is absorbed to emit light, the color temperature of each phosphor layer can be adjusted very easily.

  Furthermore, when the phosphor layer 10 is formed, the color temperature of the light emitting device 1 is measured every time the phosphor constituting layers 10a to 10c constituting the phosphor layer 10 are formed, and desired light emission is obtained. By confirming whether it is, the color temperature of the light emitting device 1 by the phosphor layer 10 can be finely adjusted in units of 100K. Thereby, it becomes possible to manufacture the light emitting device 1 including the phosphor layer 10 that emits light closer to the desired light emission than before.

  Furthermore, by adjusting the particle diameter of the phosphor 20 contained in the phosphor constituting layer 10 so as to be, for example, a predetermined particle diameter or less, each phosphor constituting layer 10a to 10c constituting the phosphor layer 20 is formed. The thickness unevenness of the phosphor layer in which the phosphor constituent layers are laminated can be reduced to 2 times or less of the average particle size of the phosphor contained, Color tone unevenness can be further reduced and color rendering can be improved.

  As a first other embodiment of the present invention, when the phosphor 20 is disposed on the light emitting surface of the light emitting element 5 coated with the adhesive 21, as shown in FIG. You may make it do. In FIG. 13, both electrodes of a power supply 55 to which a high voltage can be applied are connected to the substrate 2 and the cartridge 36 that supplies the phosphor 20 to the nozzle 35. The voltage pattern applied to the substrate 2 and the cartridge 36 by the power supply 55 is controlled by a voltage control device 56 connected to the power supply 55. With such a configuration, the phosphor 20 in the cartridge 36 can be negatively charged and electrostatically adsorbed via the nozzle 35 to the positively charged adhesive 21 on the substrate 2 side.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, this invention is not limited to the example which concerns. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims, and of course, the technical scope of the present invention is also possible. It is understood that it belongs to.

  In the embodiment described above, the case where an LED that emits ultraviolet light is used as the light-emitting element 5 has been described. However, as the light-emitting element 5, an LED other than an LED that emits light having a main emission wavelength of 410 nm or less may be used.

  In the above-described embodiment, the case where the number of the phosphor constituting layers constituting the phosphor layer 10 is three has been described, but the number of the phosphor constituting layers constituting the phosphor layer 10 may be arbitrary. Good.

  In the embodiment described above, the case where one type of phosphor 20 is contained in the phosphor layer 10 has been described. However, two or more types of phosphors may be contained in the phosphor layer 10.

  In the above-described embodiment, the case where the number of the phosphor layers 10, 11, 12 stacked on the light emitting surface of the light emitting element 5 is three has been described, but the number of the phosphor layers may be arbitrary. . Further, the case where the light emitting element 5 is sealed by filling the sealing member 15 from above the phosphor layers 10, 11, 12 has been described, but a conventionally known phosphor layer is disposed on the phosphor layer. May be. At this time, by making the phosphor contained in the conventionally known phosphor layer into fine particles having a particle size of 10 μm or less, the influence due to the sedimentation of the phosphor becomes extremely small, and the same effect as the present invention is obtained. Alternatively, the same effect can be obtained by making the amount of the phosphor contained in the conventionally known phosphor layer extremely small.

  In the above-described embodiment, the case where the adhesive 21 to be applied is heated using the heater 30 to reduce the viscosity has been described. However, the viscosity is increased by heating the adhesive 21 using a heating device other than the heater 30. You may make it reduce. Moreover, you may reduce a viscosity by diluting the adhesive agent 21 with a solvent. Further, the adhesive 21 may be diluted with a solvent and heated at the same time.

  In the above-described embodiment, the case where the particle diameter of the phosphor 20 arranged in the applied adhesive 21 is adjusted using a sieve (not shown) provided in the nozzle 35 has been described. May be used. For example, the phosphor 20 is pulverized, washed, separated, and dried by a ball mill, and then put into a shuttle. By adjusting the inner diameter of a nozzle attached to the tip of the shuttle, particles of the phosphor 20 to be sprayed by means other than a sieve are used. The diameter may be adjusted.

  The present invention will be described using examples and comparative examples.

  Example 1 shown below is a result of measuring the color tone unevenness of the light emitting device 1 according to the embodiment of the present invention, and Comparative Examples 1 to 3 measure the color tone unevenness of the light emitting devices 200, 201, and 202, respectively. It is the result. In addition, the measurement of the color tone unevenness is performed by detecting light emission from the light emitting device to be measured with a detector using the color tone unevenness measuring device 70 shown in FIG. 9 and performing spectrum analysis, as shown in FIG. Both the measurement when the optical lens 51 is not provided between the light emitting device 1 and the detector 46 and the measurement when the light is condensed via the optical lens 51 were performed.

The “half-value angle (2θ (1/2))” indicating the directivity of light emitted from the light emitting device as the measurement target was calculated from the luminance analysis result obtained by the spectroscope 48 as follows.
2θ (1/2) = | θ ₁ −θ ₂ |
Here, θ ₁ and θ ₂ are angles at which the maximum luminance value is 100% and the angle at that time is the reference angle, and the luminance is 50% when rotated from the reference angle to the position of 0 °. was a theta _1, brightness is rotated from the reference angle position side of 180 ° to _two angles to be 50% theta.

  The “color temperature difference (ΔCCT)” indicating the degree of color tone unevenness of the light emitting device as the measurement target is measured within the half-value angle (2θ (1/2)) from the spectrum analysis result obtained by the spectroscope 48. The difference between the maximum value and the minimum value of the color temperature CCT (Correlated Color Temperature). The unit is K (Kelvin).

  With respect to the color rendering properties of light emitted from the light emitting device that is the measurement target, the spectroscope 48 obtains an “average color rendering index (Ra)” indicating the degree of faithful reproduction of the reference light defined by JIS. It was calculated from the obtained spectrum analysis result.

<Example 1>
A light emitting device 1 shown in FIG. 2 was produced in which three different phosphor layers 10, 11, and 12 were directly laminated on a light emitting element 5 that emits ultraviolet light having a main emission wavelength of 405 nm. In Example 1, the phosphor 20 contained in the phosphor layer 10 is CaAlSiN ₃ : Eu, the phosphor 25 contained in the phosphor layer 11 is SrAl _{1 + x} Si _4−x O _x N _7−x : Ce, fluorescence SrAl as the phosphor 27 contained in the body layer _{12 x Si 6-x O 1} + x N 8-x: with Eu. The particle diameter of the phosphor 20 is adjusted to 10 μm or less, the particle diameter of the phosphor 25 is adjusted to 13 μm or less, and the particle diameter of the phosphor 27 is adjusted to 20 μm or less.

  When the cross section of the sample was observed, the occupancy ratios of the phosphor 20, the phosphor 25, and the phosphor 27 in the phosphor layer 10, the phosphor layer 11, and the phosphor layer 12 were both 60% and 50% or more. . The thickness unevenness (difference between the maximum thickness and the minimum thickness) of each of the phosphor layer 10, the phosphor layer 11, and the phosphor layer 17 is the phosphor 20, the phosphor 25, and the phosphor contained in each layer. The average particle size was 27 times or less. The average particle sizes of the phosphors 20, 25, and 27 contained in the phosphor layers 10, 11, and 12 were 7 μm, 10 μm, and 18 μm, respectively.

  The brightness ratio and correlated color temperature values of the light emitting device 1 were measured at a position of the light emitting device 1 of 0 to 180 ° using the color tone unevenness measuring device 70 shown in FIG. FIG. 15 shows a measurement result measured without using the optical lens 51, and FIG. 16 shows a measurement result measured by collecting light through the optical lens 51. 15 and 16, the measurement results are plotted in the coordinates where the horizontal axis is the angle (°) of the light emitting device 1 and the vertical axis is the correlated color temperature (K). FIG. 17 shows the measurement results in FIG. 15, and FIG. 18 shows the measurement results in FIG.

  15 and 17, the half-value angle (2θ (1/2)) is 115 °, the color temperature difference is ΔCCT = 33K, and the average is obtained at the reference angle (90 °) at which the luminance is maximum. The color rendering index (Ra) was 94, and the average color rendering index (Ra) was 90 or more in the half-value angle region. As shown in FIGS. 16 and 18, when the light is collected through the lens, the half-value angle (2θ (1/2)) is 19 °, the color temperature difference is ΔCCT = 219K, and the luminance is maximized. The average color rendering index (Ra) at the reference angle (90 °) was 93, and the average color rendering index (Ra) was 90 or more in the half-value angle region. From the above results, according to the light emitting device 1 of the present invention, even when the light is collected using an optical element, the color temperature difference is small and the average color rendering index (Ra) is 90 or more. White light was obtained.

<Comparative Example 1>
As Comparative Example 1, a light emitting device 200 shown in FIG. The light emitting device 200 includes a phosphor layer 210 containing a phosphor 20 that emits red light and a phosphor 25 that emits green light on the light emitting surface of the light emitting element 5 that emits blue light disposed on the substrate 2. The phosphor layer 211 is laminated in order, and the resin 15 is thickly disposed around the phosphor layer 211.

  When the cross section of the sample was observed, the occupation ratios of the phosphor 20 and the phosphor 25 in the phosphor layer 210 and the phosphor layer 211 were both 60% and 50% or more. The thickness unevenness (difference between the maximum thickness and the minimum thickness) of each of the phosphor layer 210 and the phosphor layer 211 is not more than twice the average particle diameter of the phosphor 20 and the phosphor 25 contained in each layer. Met. The average particle sizes of the phosphors 20 and 25 contained in the phosphor layers 210 and 211 were 7 μm and 10 μm, respectively.

  The brightness ratio and correlated color temperature values of the light emitting device 200 were measured at a position of the light emitting device 200 of 0 to 180 ° using the color tone unevenness measuring device 70 shown in FIG. FIG. 20 shows a measurement result measured without using the optical lens 51, and FIG. 21 shows a measurement result measured by condensing light through the optical lens 51. 20 and 21, the measurement results are plotted on the coordinates where the horizontal axis is the angle (°) of the light emitting device 200 and the vertical axis is the correlated color temperature (K). FIG. 22 shows the measurement results in FIG. 20, and FIG. 23 shows the measurement results in FIG.

  20 and 22, when the lens is not used, the half-value angle (2θ (1/2)) is 126 °, the color temperature difference is ΔCCT = 155K, and the average at the reference angle (90 °) at which the luminance is maximum. The color rendering index (Ra) was 92, and the average color rendering index (Ra) was 90 or more in the half-value angle region. However, as shown in FIGS. 21 and 23, when the light is collected through the lens, the half-value angle (2θ (1/2)) is 14 ° and the color temperature difference is ΔCCT = 1036K. The value was significantly larger. From this, it has been found that when a lens is used for light emission from the light emitting device 200, the color tone unevenness is amplified.

<Comparative example 2>
As Comparative Example 2, a light emitting device 201 shown in FIG. In the light emitting device 201, a resin is disposed as the intermediate layer 12 on the light emitting surface of the light emitting element 5 that emits ultraviolet light disposed on the substrate 2, and the red light is disposed at a position spaced apart from the light emitting element 5 through the intermediate layer 12. The phosphor layer 210 containing the phosphor 20 emitting light, the phosphor layer 211 containing the phosphor 25 emitting green light, and the phosphor layer 212 containing the phosphor 27 emitting blue light are mixed to form a thin layer. It has a configuration arranged.

  When the cross section of the sample was observed, the occupancy ratios of the phosphor 20, 210, and 27 in the phosphor layer 210, the phosphor layer 211, and the phosphor layer 212 were all 60%, which was 50% or more. It was. The thickness unevenness (difference between the maximum thickness and the minimum thickness) of each of the phosphor layer 210, the phosphor layer 211, and the phosphor 212 is the phosphor 20, the phosphor 25, and the phosphor 27 contained in each layer. The average particle size was 2 times or less. The average particle diameters of the phosphors 20, 25, and 27 contained in the phosphor layers 210, 211, and 212 were 7 μm, 10 μm, and 18 μm, respectively.

  The brightness ratio and correlated color temperature values of the light emitting device 201 were measured using the color tone unevenness measuring device 70 shown in FIG. 9 at a position of the light emitting device 201 of 0 to 180 °. FIG. 25 shows a measurement result measured without using the optical lens 51, and FIG. 26 shows a measurement result measured by condensing light through the optical lens 51. In FIGS. 25 and 26, the measurement results are plotted in coordinates where the horizontal axis is the angle (°) of the light emitting device 200 and the vertical axis is the correlated color temperature (K). FIG. 27 shows the measurement results in FIG. 25, and FIG. 28 shows the measurement results in FIG.

  25 and 27, when no lens is used, the half-value angle (2θ (1/2)) is 115 °, the color temperature difference is ΔCCT = 86K, and the average at the reference angle (90 °) at which the luminance is maximum. The color rendering index (Ra) was 92, and the average color rendering index (Ra) was 90 or more in the half-value angle region. However, as shown in FIGS. 26 and 28, when the light is condensed through the lens, the half-value angle (2θ (1/2)) is 16 °, the color temperature difference is ΔCCT = 381K, and the color temperature difference is The value was getting bigger. From this, it has been found that when the lens is used for light emission from the light emitting device 201, the color tone unevenness is amplified.

<Comparative Example 3>
As Comparative Example 3, a light emitting device 202 shown in FIG. In the light emitting device 202, a phosphor 20 that emits red light, a phosphor 25 that emits green light, and a phosphor 27 that emits blue light are mixed around the light emitting element 5 that emits ultraviolet light disposed on the substrate 2. The resin is arranged thick. The particle diameters of the phosphors 20, 25, and 27 are not adjusted.

  When the cross section of the sample was observed, the occupancy ratio of the phosphors 20, 25, and 27 in the resin 15 was 5% in total, which was 50% or less. Moreover, the thickness unevenness (difference between the maximum thickness and the minimum thickness) of the layer of the resin 15 exceeded twice the average particle diameter of the phosphors 20, 25 and 27 contained therein. The average particle diameters of the phosphors 20, 25, and 27 were 7 μm, 10 μm, and 18 μm, respectively.

  The brightness ratio and correlated color temperature values of the light emitting device 202 were measured using the color unevenness measuring device 70 shown in FIG. 9 at a position of the light emitting device 202 of 0 to 180 °. FIG. 30 shows a measurement result measured without using the optical lens 51, and FIG. 31 shows a measurement result measured by condensing light through the optical lens 51. 30 and 31, the measurement results are plotted on the coordinates where the horizontal axis is the angle (°) of the light emitting device 200 and the vertical axis is the correlated color temperature (K). 32 shows each measurement result in FIG. 30, and FIG. 33 shows each measurement result in FIG.

  30 and 32, when no lens is used, the half-value angle (2θ (1/2)) is 133 °, the color temperature difference is ΔCCT = 494K, and the average at the reference angle (90 °) at which the luminance is maximum. The color rendering index (Ra) was 91, and the average color rendering index (Ra) was 90 or more in the half-value angle region. In addition, as shown in FIGS. 31 and 33, when the light was collected through the lens, the half-value angle (2θ (1/2)) was 28 ° and the color temperature difference was ΔCCT = 829K. From this, it has been found that the light emission of the light emitting device 202 has a significant color tone difference due to a large color temperature difference regardless of the presence or absence of a lens.

  From the above Example 1 and Comparative Examples 1 to 3, in the light emitting device 1 (Example 1) of the present invention, the value of the color temperature difference ΔCCT indicating the degree of color unevenness with respect to the half-value angle of 19 ° is 219K. Compared with the values 381 to 1036K of the color temperature difference ΔCCT with respect to the half-value angle of 14 to 28 ° in the case of the light emitting devices 200 to 202 (Comparative Examples 1 to 3), the color tone unevenness of the light emitted by the light emitting device is extremely high. It can be seen that it has been reduced. In addition, the average color rendering index Ra of Example 1 for the light emitting device 1 of the present invention is 93. This means that the white light emitted from the light emitting device 1 of the present invention can reproduce light closer to the reference light. Since this phosphor layer 10, 11, 12 contains non-directional phosphors 20, 25, 27, the white light has a reduced directivity in the synthesized light. I understand.

  The present invention is particularly useful for a light-emitting device that emits white light, for example, used for an illumination light source, a liquid crystal backlight light source, and the like and requires low color tone unevenness and high color rendering.

DESCRIPTION OF SYMBOLS 1 Light-emitting device 2 Board | substrate 3 Side wall 5 Light emitting element 6 External electrode 7 Conductive wire 10, 11, 12 Phosphor layer 10a-10c, 11a-11c, 12a-12c Phosphor constituent layer 15 Sealing member 20, 25, 27 Fluorescence Body 21, 26, 28 Adhesive 30 Heater 31 Discharge port 35 Nozzle 36 Cartridge 37 Piping 40 Storage part 41 Piping 42 Pressure adjusting device 43 On-off valve 46 Detector 47 Optical fiber 48 Spectrometer 49 Wiring 50 Power supply 51 Optical lens 55 High voltage power supply 56 Voltage control device 100, 200 to 202 Light emitting device as a comparative example 101 Map light 102 Optical lens 103 Light diffusing material 210 to 212 Phosphor layer as a comparative example

Claims (11)

The light emitting surface of the light emitting element having a main emission wavelength of 410 nm or less has a configuration in which one or more phosphor layers containing a phosphor that absorbs light from the light emitting element and converts the wavelength to emit light are stacked.
The phosphor layer has a configuration in which a plurality of phosphor constituent layers are laminated,
The phosphor layer has a difference between the maximum thickness and the minimum thickness not more than twice the average particle diameter of the phosphor,
The phosphor occupancy ratio in the phosphor constituent layer farthest from the light emitting element is 50% or less, and the phosphor occupancy ratio in other phosphor constituent layers is 60% or more. A light emitting device. The light emitting device according to claim 1, wherein the thickness of the phosphor layer is 5 times or less of an average particle diameter of the phosphor. The phosphor constituting layer is formed by applying an adhesive on the light emitting surface of the light emitting element, and fixing the phosphor to the applied adhesive, and the adhesive has an average particle diameter of the phosphor. The light emitting device according to claim 1, wherein the light emitting device is applied to the following thickness. The light emitting device according to any one of claims 1 to 3, comprising a plurality of phosphor layers having different phosphors. Two or more phosphor layers are laminated on the light emitting surface of the light emitting element,
The main emission wavelength of the phosphor contained in the phosphor layer near the light emitting element is different from the main absorption wavelength of the phosphor contained in the phosphor layer far from the light emitting element. The light-emitting device according to claim 1. A light emitting element having a main emission wavelength of 410 nm or less; and a phosphor layer containing a phosphor that absorbs light from the light emitting element and emits light after wavelength conversion, and a difference between the maximum thickness and the minimum thickness Is a method for manufacturing a light emitting device, wherein the phosphor layer having an average particle size of not more than twice the average particle diameter of the phosphor is directly formed on the light emitting surface of the light emitting element so as to cover the light emitting surface of the light emitting element. And
The phosphor layer is composed of a plurality of phosphor constituent layers,
The phosphor occupancy in the phosphor constituent layer farthest from the light emitting element is 50% or less, and the phosphor occupancy in other phosphor constituent layers is 60% or more. A method of manufacturing a light emitting device, wherein the body constituting layer is formed. The method of manufacturing a light emitting device according to claim 6, wherein a thickness of the phosphor layer is formed to be 5 times or less of an average particle diameter of the phosphor. When forming the phosphor layer, after applying an adhesive thinner than the average particle diameter of the phosphor on the light emitting element, the phosphor is fixed to the applied adhesive to form a phosphor structure. The method of manufacturing a light emitting device according to claim 6 or 7, wherein a forming step of forming a layer is performed, and the phosphor constituting layer is laminated until a desired color temperature is obtained for the phosphor layer. The method for manufacturing a light-emitting device according to claim 10, wherein the adhesive is applied in a state where the surface of the application is heated by a heater. When laminating the one or more phosphor layers, the main emission wavelength of the phosphor contained in the phosphor layer closer to the light emitting element is contained in the phosphor layer far from the light emitting element. The method for manufacturing a light emitting device according to claim 6, wherein the layers are laminated so as to be different from a main absorption wavelength of the phosphor. When laminating the plurality of phosphor constituent layers, repeating the application of the adhesive, the fixing of the phosphor, the temporary curing of the adhesive, the measurement of the color temperature, and the verification of the measurement result The method for manufacturing a light-emitting device according to claim 6, wherein a desired color temperature is obtained by:

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