TWI732821B - Light emitting device and backlight including the light emitting device - Google Patents

Abstract

A light emitting device includes at least three light emitting elements arranged side by side, and one or more light transmissive members each containing a phosphor and covering the light emitting elements. The at least three light emitting elements include two outer light emitting elements arranged on outer sides, and an inner light emitting element arranged between the two outer light emitting elements and having a different peak emission wavelength than a peak emission wavelength of the two outer light emitting elements. The phosphor has a longer peak emission wavelength than the peak emission wavelengths of the outer light emitting elements and the peak emission wavelength of the inner light emitting element. The two outer light emitting elements and the inner light emitting element are connected in series.

Description

Light-emitting device and backlight with light-emitting device

The present invention relates to a light-emitting device and a backlight provided with the light-emitting device.

Generally speaking, light-emitting devices using light-emitting elements such as light-emitting diodes are widely used as various light sources such as backlights of liquid crystal displays, LED bulbs, LED fluorescent lamps, and ceiling lamps. For example, the light-emitting device disclosed in Patent Document 1 includes a red phosphor, a light-emitting element that emits blue light, and a light-emitting element that emits green light. As a result, a light-emitting device used as a backlight of a liquid crystal display can obtain high color reproducibility. [Prior Art Document] [Patent Document] [Patent Document 1] Japanese Patent Laid-Open No. 2007-158296

[Problem to be Solved by the Invention] However, in the light-emitting device disclosed in Patent Document 1, compared with a light-emitting device with a green phosphor, the light emitted from the light-emitting element is more straightforward. As a light-emitting device, there is a risk of uneven color. Therefore, the object of the present invention is to provide a light-emitting device that suppresses color unevenness. [Technical Means for Solving the Problem] The light-emitting device of the present invention has at least three light-emitting elements arranged side by side and a light-transmitting member including phosphors, and at least three light-emitting elements have: 2 outer light-emitting elements, which Etc. are arranged on the outside; and the inner light-emitting element, which is arranged inside the two outer light-emitting elements and has an emission peak wavelength different from the emission peak wavelength of the two outer light-emitting elements; and the phosphor has more outer light-emitting elements and inner light-emitting The emission peak wavelength of the element is a long emission peak wavelength, and the two outer light-emitting elements and the inner light-emitting element are connected in series. [Effects of the Invention] According to the present invention, it is possible to provide a light-emitting device with suppressed color unevenness.

Hereinafter, the embodiments of the present invention will be described in detail based on the drawings. Furthermore, in the following description, terms that indicate a specific direction or position (for example, "up", "down", and other terms including these terms) are used as necessary, but these terms are used to make It is easier to understand the invention with reference to the drawings, and the technical scope of the invention is not limited by the meaning of these terms. In addition, the parts with the same symbols shown in the plural drawings indicate the same or equivalent parts or components. Furthermore, the embodiment shown below is an example of a light-emitting device for embodying the technical idea of the present invention, and does not limit the present invention to the following. In addition, the dimensions, materials, shapes, and relative arrangements of the components described in the embodiments are not intended to limit the scope of the present invention to the purpose of these, but are intended to be illustrative, as long as there is no specific description. The size or positional relationship of the components shown in the drawings are sometimes exaggerated in order to make it easier to understand. Furthermore, the relationship between color names and chromaticity coordinates, the relationship between the wavelength range of light and the color names of monochromatic light, etc. are based on JIS Z8110. The light-emitting device of the present invention has at least three light-emitting elements arranged side by side, and a translucent member including a phosphor. At least three light-emitting elements include two outer light-emitting elements arranged on the outside and an inner light-emitting element arranged on the inner side of the two outer light-emitting elements. Furthermore, the two outer light-emitting elements and the inner light-emitting element are connected in series. The light-emitting device of the present invention having such a configuration can achieve excellent color mixing between the emitted light of each light-emitting element and the emitted light of the phosphor excited by the emitted light of the light-emitting element, and can suppress the color unevenness of the light-emitting device. Hereinafter, the details of the light-emitting device according to the embodiment of the present invention will be described. 1. Embodiment 1 FIG. 1A is a schematic plan view of the light-emitting device 100, and FIG. 1B is a schematic cross-sectional view taken along the line Ib-Ib of FIG. 1A. In FIG. 1A, the description of the phosphor 4 is omitted so that the outer light emitting element P and the inner light emitting element Q arranged in the translucent member 3 can be easily recognized. In the light-emitting device 100, two outer light-emitting elements P and one inner light-emitting element Q are arranged side by side on the upper surface of the first spring 36a arranged on the bottom surface of the recess of the resin package 2. In addition, the inner light-emitting element Q is arranged inside the two outer light-emitting elements P. The interval between the light-emitting elements is preferably the same, but may be different. In this specification, the term “side-by-side arrangement” means that at least three light-emitting elements are arranged in a line shape. In other words, it means that at least a part of the side surfaces of adjacent light-emitting elements are arranged opposite to each other. In addition, the term "outside light-emitting element" refers to a light-emitting element arranged on the end side among a plurality of light-emitting elements arranged side by side. The outer light-emitting element P may have one on one end side, or may have two or more. When there are two or more outer light-emitting elements P on one end side, the two or more outer light-emitting elements P emit light of the same color, more specifically, when the outer light-emitting element P is a blue light-emitting element , Use light-emitting elements whose peak wavelength is above 430 nm and less than 490 nm. When two or more outer light-emitting elements P are arranged on one end side, for example, the two or more outer light-emitting elements P may be arranged along the arrangement direction L of a plurality of light-emitting elements arranged side by side, or may be opposite to the arrangement direction L is arranged vertically. In addition, the "inner light-emitting element" refers to a light-emitting element that is sandwiched by the outer light-emitting element P and arranged. The inner light-emitting element Q only needs to be sandwiched by at least two outer light-emitting elements P, and it does not need to be the center of a plurality of light-emitting elements or be arranged in the center of the bottom surface of the recess. There may be one inner light-emitting element Q, or two or more. When there are two or more inner light-emitting elements Q, the two or more inner light-emitting elements Q emit light of the same color. More specifically, when the inner light-emitting element Q is a green light-emitting element, the respective emission peaks are used A light-emitting element with a wavelength in the range of 490 nm or more and 570 nm or less. When there are two or more inner light-emitting elements Q, the inner light-emitting element Q may be arranged along the arrangement direction L of a plurality of light-emitting elements arranged side by side, or may be arranged perpendicular to the arrangement direction L, for example. In the light-emitting device 100 shown in FIGS. 1A and 1B, a blue light-emitting element (first light-emitting element 10b) is used as the outer light-emitting element P, and a green light-emitting element (second light-emitting element 20g) is used as the inner light-emitting element Q. The light-emitting device 100 may have three or more outer light-emitting elements P (first light-emitting element 10b) according to the amount of light to be obtained, and may have two or more inner light-emitting elements Q (second light-emitting element 20g). In the embodiment shown in FIG. 1A, the first light-emitting element 10b, the second light-emitting element 20g, and the first light-emitting element 10b are arranged side by side in this order from the left. Furthermore, in the embodiment shown in FIG. 1A, a blue light-emitting element is used as the outer light-emitting element P, and a green light-emitting element is used as the inner light-emitting element Q. However, it is not limited to this, and a green light-emitting element may be used as the outer light-emitting element. P, a blue light-emitting element is used as the inner light-emitting element Q. Also, according to the desired light-emitting characteristics, the number of first light-emitting elements 10b may be greater than the number of second light-emitting elements 20g, and the number of second light-emitting elements 20g may be greater than the number of first light-emitting elements 10b. There are many, and the number of the first light-emitting elements 10b and the second light-emitting elements 20g may be the same. In the light-emitting device 100A of FIG. 2, two first light-emitting elements 10b and two second light-emitting elements 20g are provided, and two second light-emitting elements 20g are arranged inside the two first light-emitting elements 10b. By adjusting the number of light-emitting elements in this way, a light-emitting device with any color tone or light quantity can be set. The peak wavelength of light emitted by the first light-emitting element 10b is in the range of 430 nm or more and less than 490 nm (the wavelength range of the blue region), and among them, it is preferably in the range of 440 nm or more and 470 nm or less. In addition, the peak wavelength of the light emitted by the second light-emitting element 20g is in the range of 490 nm or more and 570 nm or less (wavelength range of the green region), and it is preferably in the range of 520 nm or more and 550 nm or less. In particular, the second light-emitting element 20g is preferably a light-emitting element having a half-value width of 40 nm or less, and more preferably a light-emitting element having a half-value width of 30 nm or less. Thereby, compared with the case where green light is obtained by using a green phosphor, the green light can easily have a sharp peak. As a result, the liquid crystal display device provided with the light-emitting device 100 can achieve high color reproducibility. The first light-emitting element 10b and the second light-emitting element 20g are respectively electrically connected to an external circuit such as a wiring layer of the mounting substrate, and emit light by power supplied through the external circuit. In the light-emitting device 100 shown in FIG. 1A, one of the positive electrode and the negative electrode of the first light-emitting element 10b arranged on one end side is connected to the first spring 36a via a wire 6, and is arranged on the other end side One of the positive electrode and the negative electrode of the first light-emitting element 10b is connected to the second spring 36b via the wire 6. Furthermore, the second light-emitting element 20g arranged on the inner side is electrically connected to the first light-emitting element 10b arranged adjacently via the wire 6. In the light-emitting device 100 shown in FIG. 1A, the first light-emitting element 10b arranged on one end side, the second light-emitting element 20g arranged on the inner side, and the first light-emitting element 10b arranged on the other end side are sequentially connected in series. . Furthermore, in the light-emitting device 100, the resin package 2 is used as the support body 7. In this specification, the so-called support system refers to a member for arranging the first light-emitting element 10b and the second light-emitting element 20g, for example, a resin package or ceramic substrate including a conductive member for supplying power to the light-emitting element. The conductive member is arranged on the surface of the support body 7, and for example, a reed or a wiring layer is used. In the light-emitting device 100 shown in FIGS. 1A and 1B, a translucent member 3 is arranged in the recess of the resin package 2. The translucent member 3 may be resin, glass, or the like, for example. The light-transmitting member 3 includes a phosphor 4 having an emission peak wavelength longer than the emission peak wavelength of the outer light-emitting element and the inner light-emitting element. In the light-emitting device 100 shown in FIG. 1B, as the phosphor 4, a phosphor 4 having an emission peak wavelength in the range of 580 nm or more and 680 nm or less is used. The phosphor 4 absorbs a part of the blue light emitted by the first light-emitting element 10b and emits red light. That is, the phosphor 4 converts the wavelength of blue light into red light having a different wavelength. It is preferable that the phosphor 4 absorbs the green light of the second light-emitting element 20g and emits red light. That is, it is preferable that the phosphor 4 does not substantially convert green light into red light. Moreover, it is preferable that the reflectance of the phosphor 4 with respect to the green light is 70% or more on average in the range of the wavelength of the green light. By setting the phosphor 4 to have a higher reflectivity to green light, that is, a phosphor that absorbs less green light, that is, a phosphor that performs less wavelength conversion on green light, so that the design of the light-emitting device can be achieved. Easier. If a red phosphor with a large absorption of green light is used, not only the first light-emitting element 10b, but also the second light-emitting element 20g must consider the wavelength conversion of the phosphor 4 to study the output balance of the light-emitting device. On the other hand, if the phosphor 4 that hardly converts the wavelength of green light is used, the output balance of the light-emitting device can be designed by considering only the wavelength conversion of the blue light emitted by the first light-emitting element 10b. As such a preferable phosphor 4, the following red phosphors can be cited. The phosphor 4 is at least one of these. The first type is a red phosphor whose composition is represented by the following general formula (I). A ₂ MF ₆ : Mn ⁴⁺ (I) where, in the above general formula (I), A is selected from at least one element selected from the group consisting of ^{K, Li, Na, Rb, Cs and NH 4+, M} At least one element selected from the group consisting of group 4 elements and group 14 elements. Group 4 elements are titanium (Ti), zirconium (Zr) and hafnium (Hf). Group 14 elements are silicon (Si), germanium (Ge), tin (Sn) and lead (Pb). Specific examples of the first type of red phosphor include K ₂ SiF ₆ : Mn ⁴⁺ , K ₂ (Si,Ge)F ₆ : Mn ⁴⁺ , and K ₂ TiF ₆ : Mn ⁴⁺ . The second type is a red phosphor whose composition is represented by 3.5MgO·0.5MgF ₂ ·GeO ₂ : Mn ⁴⁺ or a red phosphor whose composition is represented by the following general formula (II). (x－a)MgO・a(Ma)O・b/2(Mb) ₂ O ₃・yMgF ₂・c(Mc)X ₂・(1-d－e)GeO ₂・d(Md)O ₂・e(Me) ₂ O ₃ : Mn ⁴⁺ (II) where, in the above general formula (II), Ma is at least one selected from Ca, Sr, Ba, and Zn, and Mb is selected from Sc, La, Lu At least one, Mc is at least one selected from Ca, Sr, Ba, Zn, X is at least one selected from F, Cl, Md is at least one selected from Ti, Sn, Zr, Me is selected from B, At least one of Al, Ga, and In. Also, for x, y, a, b, c, d, e, 2≦x≦4, 0<y≦2, 0≦a≦1.5, 0≦b<1, 0≦c≦2, 0≦ d≦0.5, 0≦e<1. Such a light-transmitting member 3 covers at least a part of the first light-emitting element 10b and at least a part of the second light-emitting element 20g. In addition, the light-transmitting member 3 is arranged such that at least a part thereof is located between the first light-emitting element 10b and the second light-emitting element 20g. It is preferable that the light-transmitting member 3 straddles the first light-emitting element 10b, the second light-emitting element 20g and is arranged in contact with the first light-emitting element 10b and the second light-emitting element 20g. 1A and 1B, the first light emitting element 10b is mounted on the surface other than the bottom surface of the first reed 36a or the second reed 36b (that is, the upper surface and the side surface) as a whole can be substantially formed by the light-transmitting member 3. cover. Similarly, the entire surface of the second light emitting element 20g other than the bottom surface (that is, the upper surface and the side surface) contacting the first reed 36a or the second reed 36b can be substantially covered by the light-transmitting member 3. By covering the first light-emitting element 10b with the light-transmitting member 3, a part of the blue light emitted from the first light-emitting element 10b is absorbed by the phosphor 4 in the light-transmitting member 3, and the phosphor 4 emits red light. Furthermore, the blue light that has not been wavelength-converted by the phosphor 4 and the red light emitted by the phosphor 4 pass through the translucent member 3 and exit from the upper surface of the translucent member 3 (the light extraction surface of the light-emitting device 100) to the outside. . On the other hand, a part of the green light emitted from the second light-emitting element 20g is wavelength-converted by the phosphor 4 into red light, (preferably, it is not converted into red light (or hardly converted) by the phosphor 4) and passes through The light-transmitting member 3 emits outward from the upper surface of the light-transmitting member 3. In addition, blue light, red light, and green light are mixed on the outer side of the translucent member 3, for example, light of a desired color such as white light can be obtained. Furthermore, a part of the green light emitted from the second light-emitting element 20g is preferably scattered by the phosphor 4 without changing the wavelength. In this case, the intensity distribution of the green light emitted from the light-emitting device 100 becomes uniform, so that the occurrence of color unevenness can be suppressed. Furthermore, for example, the translucent member 3 is made of a sealing resin, and the resin covering the first light-emitting element 10b and the resin covering the second light-emitting element 20g are the same translucent member 3 from the viewpoint of productivity. More appropriate. Hereinafter, the details of the elements constituting the light-emitting device 100 will be described.・Light-emitting element Hereinafter, a preferable arrangement of the first light-emitting element 10b and the second light-emitting element 20g is illustrated. As shown in FIG. 1A, the arrangement direction L of the two first light-emitting elements 10b and second light-emitting elements 20g arranged side by side can be parallel to the longitudinal direction of the support 7 (the left-right direction in FIGS. 1A and 1B). In addition, the arrangement direction L of the two first light-emitting elements 10b and the second light-emitting element 20g can be made parallel to the longitudinal direction of the light-emitting element placement surface of the support 7. Here, the so-called light-emitting element mounting surface of the support 7 is the surface on which the light-emitting element is mounted in the support 7. In FIGS. 1A and 1B, the light-emitting element mounting surface refers to the entire surface of the first spring 36a exposed on the bottom surface of the recess. By providing these configurations, the light emitted from the light-emitting element can be more uniformly dispersed throughout the entire light-emitting device 100. In the light-emitting device 100, the second light-emitting element 20g is sandwiched between the two first light-emitting elements 10b and arranged. With this arrangement, the light emitted from the second light-emitting element 20g can be easily mixed with the light emitted from the two first light-emitting elements 10b arranged outside the second light-emitting element 20g. Therefore, as a result, the color can be easily mixed. Further suppress the occurrence of uneven color. The distance between the opposing side surfaces of the first light-emitting element 10b and the second light-emitting element 20g is preferably 10 μm to 300 μm, and more preferably 50 μm to 150 μm. Thereby, the first light-emitting element 10b and the second light-emitting element 20g can be arranged close to each other, and therefore, the color mixing property of the light-emitting device can be further improved. In the light-emitting device 100, the distance between the light-emitting elements of the first light-emitting element 10b and the second light-emitting element 20g arranged on the left and the distance between the light-emitting elements of the first light-emitting element 10b and the second light-emitting element 20g arranged on the right are set Are roughly equal. When a plurality of each of the first light-emitting element 10b and the second light-emitting element 20g is provided, it is preferable that the light-emitting elements are arranged at equal intervals. Furthermore, it is preferable that the plurality of light-emitting elements are arranged symmetrically with respect to the center line C perpendicular to the arrangement direction L. In the light-emitting device 100 shown in FIG. 1A, the two first light-emitting elements 10b and the second light-emitting elements 20g are arranged symmetrically with respect to the center line C. By arranging a plurality of light-emitting elements including the first light-emitting element 10b and the second light-emitting element 20g symmetrically with respect to the center line C, the distance between the light-emitting elements becomes equal, and the number of light-emitting elements The area of the light-emitting surface in the top view is equal to the left and right. With these configurations, the color unevenness of the light-emitting device can be suppressed. Furthermore, when the light-emitting device has an ideal light distribution according to the application, the distance between the light-emitting elements can also be different. In addition, at least three light-emitting elements including two first light-emitting elements 10b and second light-emitting elements 20g are arranged side by side in one row, and such rows can be arranged in plural rows. That is, at least three light-emitting elements including two first light-emitting elements 10b and second light-emitting elements 20g may be neatly arranged on a straight line, and at least three light-emitting elements including two first light-emitting elements 10b and second light-emitting elements 20g The three light-emitting elements are neatly arranged on another straight line. The above-mentioned preferred configurations can be combined with each other. The first light-emitting element 10b and the second light-emitting element 20g may be semiconductor elements such as light-emitting diodes (LEDs) that emit light by applying a voltage. As the semiconductor used in each light-emitting element, a nitride-based semiconductor (In _X Al _Y Ga _1-XY N, 0≦X, 0≦Y, X+Y≦1) or the like can be used. That is, the first light-emitting element 10b and the second light-emitting element 20g may be nitride semiconductor elements. The planar shape of the first light-emitting element 10b and the second light-emitting element 20g may be a square or a rectangle, or they may be combined to arrange a plurality of them. The number or shape of the light-emitting elements can be appropriately selected according to the shape or size of the support 7. As an example of the shape of the light-emitting element, as shown in FIGS. 3A and 3B, the planar shape of the first light-emitting element 10b and the second light-emitting element 20g may be a triangle or a hexagon. In the light-emitting device 100B shown in FIG. 3A, the side surface of the first light-emitting element 10b opposite to the second light-emitting element 20g and the side surface of the second light-emitting element 20g opposite to the first light-emitting element 10b are arranged in parallel. . In other words, the first light-emitting element 10b and the second light-emitting element 20g are arranged such that the area between the first light-emitting element 10b and the second light-emitting element 20g formed by b1, b2, g1, and g2 becomes a substantially parallelogram. In addition, in the light-emitting device 100C shown in FIG. 3B, the side surface of the first light-emitting element 10b opposite to the second light-emitting element 20g and the side surface of the second light-emitting element 20g opposite to the first light-emitting element 10b become Parallel configuration. By using such a light-emitting element, the ratio of the light-emitting element to the light-emitting element mounting surface of the support 7 can be increased, and therefore, a light-emitting device with good light extraction can be set. The light output of the first light-emitting element 10b and the light output of the second light-emitting element 20g may be the same. In addition, the light output of the first light-emitting element 10b may be different from the light output of the second light-emitting element 20g according to desired characteristics such as color reproducibility. As one embodiment for obtaining excellent color reproducibility, the ratio of the light output of the second light-emitting element 20g to the light output of the first light-emitting element 10b can be set to 0.3 or more and 0.7 or less. In addition, the ratio of the total light output of all the second light-emitting elements 20g to the total light output of all the first light-emitting elements 10b used can be set to 0.2 or more and 0.6 or less. The so-called "light output" in this manual refers to the radiation beam of JIS Z 8113. In addition, the ratio of the light output of the light-emitting element can be calculated from the ratio of the integrated value of the light-emitting spectra of the blue light-emitting element and the green light-emitting element by measuring the emission spectrum with a spectrophotometer. The light output of the light-emitting element is determined according to the peak wavelength of the light-emitting element, the planar area of the light-emitting element, or the type of semiconductor laminate that the light-emitting element has. In addition, in the light-emitting device 100 shown in FIG. 1B, the upper surface of the second light-emitting element 20g is arranged so as to be higher than the upper surface of the first light-emitting element 10b. That is, the upper surface of the second light-emitting element 20g is arranged in the vicinity of the light extraction surface (the upper surface of the translucent member 3) of the light-emitting device 100 than the upper surface of the first light-emitting element 10b. The height difference between the upper surface of the first light-emitting element 10b and the second light-emitting element 20g is, for example, 50 μm to 150 μm, preferably 100 μm to 120 μm. With this arrangement, for example, even when the light output of the second light emitting element 20g is lower than the light output of the first light emitting element 10b to a certain extent, excellent color reproducibility can be obtained. Furthermore, it is not limited to this, and the upper surface of the second light-emitting element 20g may be arranged on the lower side than the upper surface of the first light-emitting element 10b. The upper surface of the first light-emitting element 10b and the second light-emitting element 20g The upper surface can also be at the same height.・Light-transmitting member The light-transmitting member 3 is formed of any material such as resin or glass material, and includes the phosphor 4. When the translucent member 3 is formed of resin, any resin can be used. In addition, the light-transmitting member 3 may contain a diffusion material such as _{TiO 2} or SiO _2. Thereby, the light emitted by the first light-emitting element 10b, the second light-emitting element 20g, and the phosphor 4 can be sufficiently diffused. As such preferable resins, silicone resins, epoxy resins, etc. can be exemplified. After the resin is brought into a molten state and the phosphor 4 is mixed and dispersed, the resin in which the phosphor 4 is dispersed is filled in the recess of the resin package 2 to harden the resin, thereby forming the translucent member 3.・Resin package 2 in which the support is one form of the support 7 can be formed of any resin. As the resin, thermosetting resins, thermoplastic resins, etc. can be used, and preferred resins include polyester resins such as nylon resins, epoxy resins, silicone resins, and unsaturated polyesters. It is also possible to arrange a reflective material such as silver (Ag) plating on the surface of the recessed portion of the resin package 2 or form a member with higher reflectivity on the surface of the recessed portion. Thereby, the reflectivity of the light on the surface of the recess can be improved, and the efficiency of the light emitting device 100 can be further improved by reflecting the light reaching the surface of the recess to the exit direction more. Instead of the resin package with the recessed portion, it may be provided as a support with connection terminals arranged on the surface of an insulating substrate containing ceramics, resins, dielectrics, glass, or composite materials such as ceramics, resins, dielectrics, and glass. It is also possible to arrange the first light-emitting element 10b and the second light-emitting element 20g on the support, for example, by pouring to cover the first light-emitting element 10b and the second light-emitting element 20g to form the translucent member 3 including the phosphor 4 . In addition, as a modified example of the light-emitting device 100 that does not use a support, the light-emitting device 100D shown in FIGS. 4A and 4B can be exemplified. In the light-emitting device 100D shown in FIGS. 4A and 4B, two first light-emitting elements 10b and second light-emitting elements 20g, a first light-transmitting member 12 provided on the side surface of each light-emitting element, and a cover The covering member 13 on the outer surface of the translucent member 12. Furthermore, the light-emitting device 100D may be provided with the second light-transmitting member 15 or the third light-transmitting member 16 containing the phosphor 4 on the upper surface side which functions as a light-emitting surface. It is preferable that the first light-transmitting member 12, the second light-transmitting member 15, and the third light-transmitting member 16 use a member having a high light transmittance, and the first light-transmitting member 12 and the third light-transmitting member The member 16 does not include a light diffusing material or the like in order to efficiently transmit the light from the light emitting element. The first light-emitting element 10b shown in FIG. 4B includes a light-transmitting substrate 27, a semiconductor laminate 28, and a pair of electrodes 251, 252. The light-transmitting substrate 27 is arranged on the upper surface side of the first light-emitting element 10b, and The semiconductor laminate 28 is arranged on the lower surface side of the first light emitting element 10b. Furthermore, one of the pair of electrodes 251 and 252 of the first light-emitting element 10b is exposed from the covering member 13 and is exposed to the lower surface of the light-emitting device 100D. The same applies to the second light-emitting element 20g. The covering member 13 covers the outer surface of the first light-transmitting member 12 provided on the side surface of each light-emitting element and the exposed portion of the side surface of each light-emitting element. The covering member 13 is formed of a material that satisfies a specific relationship with the first light-transmitting member 12 and each light-emitting element in the magnitude relationship of the thermal expansion coefficient. Specifically, the difference in thermal expansion coefficient between the first translucent member 12 and each light-emitting element (referred to as the "first thermal expansion coefficient difference ΔT30") and the difference in thermal expansion coefficient between the covering member 13 and each light-emitting element (referring to This is referred to as "the second thermal expansion coefficient difference ΔT40") The material of the covering member 13 is selected so that ΔT40<ΔT30 for comparison. Thereby, it can suppress that the 1st translucent member 12 peels from each light-emitting element. The resin material that can be used for the covering member 13 is particularly preferably thermosetting and translucent resins such as silicone resin, silicone modified resin, epoxy resin, and phenol resin. In addition, the covering member 13 may be formed of a light reflective resin. The so-called light-reflective resin refers to a resin material with a reflectance of 70% or more with respect to the light from the light-emitting element. The light reaching the covering member 13 is reflected toward the upper surface side (light emitting surface side) of the light emitting device 100D, whereby the light extraction efficiency of the light emitting device 100D can be improved. The first light-transmitting member 12 covers the side surface of each light-emitting element, and guides the light emitted from the side surface to the upper surface direction of the light-emitting device 100D. That is, the first light-transmitting member 12 is used for extracting the light to the light-emitting element through the first light-transmitting member 12 before the light reaching the side surface of each light-emitting element is reflected on the side surface and attenuated in the light-emitting element. The outer member. The first light-transmitting member 12 can be used for the members exemplified in the light-emitting device 100, and is particularly preferably a thermosetting light-transmitting resin such as silicone resin, silicone modified resin, epoxy resin, and phenol resin. For the second light-transmitting member 15 and the third light-transmitting member 16, the members exemplified in the first light-transmitting member 12 may also be used. Since the first light-transmitting member 12 is in contact with the side surface of the light-emitting element, it is easily affected by the heat generated in the light-emitting element during lighting. Since the thermosetting resin is excellent in heat resistance, it is suitable for the first translucent member 12. Furthermore, it is preferable that the light transmittance of the first translucent member 12 is high. Therefore, it is generally preferable that no additives that reflect, absorb or scatter light are added to the first translucent member 12. However, there are also cases where it is preferable to add additives to the first translucent member 12 in order to impart more desirable characteristics. For example, in order to adjust the refractive index of the first light-transmitting member 12, or to adjust the viscosity of the first light-transmitting member 12 before curing, various fillers may be added. In the light-emitting device 100D shown in FIGS. 4A and 4B, the second light-transmitting member 15 containing the phosphor 4 is arranged on the upper surface side of the first light-emitting element 10b which functions as a light-emitting surface, and emits light in the second The third light-transmitting member 16 is arranged on the upper surface side of the element 20g that functions as a light-emitting surface. It is preferable that the third light-transmitting member 16 arranged on the upper surface side of the second light-emitting element 20g is not added with an additive that reflects, absorbs, or scatters the light emitted from the second light-emitting element 20g. With this configuration, the light emitted from the first light-emitting element 10b, the second light-emitting element 20g, and the phosphor 4 is mixed, and for example, light of a desired color such as white light can be obtained. Furthermore, as shown in FIG. 4B, the first light-emitting element 10b and the second light-emitting element 20g are connected in series by a metal film 14 formed by sputtering or the like. By providing such a metal film 14, the heat from the light-emitting element can be efficiently released to the outside. The light emitting device 100 can be manufactured by the following manufacturing method. After arranging the first reed 36a and the second reed 36b in the mold, resin is filled in the mold to integrally form the resin part, the first reed 36a, and the second reed 36b, and the resin package 2 is obtained. Two first light-emitting elements 10b and second light-emitting elements 20g are arranged on the first spring 36a exposed on the bottom surface of the recess of the resin package 2. Thereafter, as shown in FIG. 1A, the first reed 36a and the first light-emitting element 10b, the first light-emitting element 10b and the second light-emitting element 20g, and the second light-emitting element 20g arranged on the left side are arranged with the wire 6 The first light emitting element 10b and the first light emitting element 10b on the right side are respectively connected to the second reed 36b. Next, the molten resin containing the phosphor 4 is filled into the recesses of the resin package 2 so that at least a part of it is in contact with the first light-emitting element 10b and the second light-emitting element 20g. After the phosphor 4 is deposited, the resin Hardening, thereby forming the translucent member 3. Furthermore, the light-emitting device 100 described above is a top-view type light-emitting device in which the upper surface of the light-emitting device is used as the light extraction surface and the lower surface is used as the mounting surface. However, it is not limited to this. The light-emitting device of the present invention also includes a so-called side-view type light-emitting device in which the surface adjacent to the light extraction surface is used as the mounting surface and the light is emitted in a direction parallel to the mounting surface. 2. Embodiment 2 FIGS. 5A and 5B are schematic plan views showing a backlight 200 of Embodiment 2. FIG. The backlight 200 includes the light emitting device 100 as described below. However, the light-emitting device 100 used in the following description can also be replaced with light-emitting devices 100A to 100D. The backlight 200 has a casing 21, a light guide plate 22 disposed in the casing 21, and a light emitting device 100 disposed in the casing 21 and emitting light toward the light guide plate 22. The backlight 200 irradiates the light from the light-emitting device 100 through the light guide plate 22 to a required device such as a liquid crystal panel. The housing 21 can be formed in a way that its inner surface reflects light. For example, the inner surface can be made white. At least one of the four side surfaces of the light guide plate 22 is used as an incident surface (light incident part). In the embodiment shown in FIG. 5A, the side surface located below is set as the incident surface. The light emitting device 100 is arranged in such a way that the light extraction surface and the incident surface face each other. Preferably, the light emitting device 100 is arranged in plural along the incident surface. The light emitted from the light emitting device 100 enters the light guide plate 22 from the incident surface. In the case of using a plurality of light-emitting devices 100, the lights emitted from different light-emitting devices 100 are mixed inside the light guide plate 22. The upper surface of the light guide plate 22 becomes an exit surface. The light emitted from the light guide plate 22 advances toward these devices due to the necessary devices such as a liquid crystal panel disposed on the exit surface. The light extraction surface of the light emitting device 100 and the light incident portion (incident surface) of the light guide plate 22 can be arranged in the same length direction. The light of the light emitting device 100 can be guided to the light guide plate 22 with higher efficiency by setting the length direction of the light extraction surface of the light emitting device 100 and the length direction of the light incident surface of the light guide plate to be parallel. FIG. 5B is a schematic cross-sectional view showing a modification example of the backlight 200 of the second embodiment. The backlight 200 may also be a so-called direct type backlight device in which a plurality of light-emitting devices 100 are arranged directly under the light guide plate 22 as shown in FIG. 5B. [Industrial Applicability] The light-emitting device of the present invention can be used, for example, as a backlight of a liquid crystal display.

2‧‧‧Resin package 3‧‧‧Translucent member 4‧‧‧Fluorescent body 6‧‧Wire 7‧‧‧Support 10b‧‧‧First light-emitting element 20g‧‧‧Second light-emitting element 12‧ ‧‧The first light-transmitting member 13‧‧‧The covering member 14‧‧‧Metal film 15‧‧‧The second light-transmitting member 16‧‧‧The third light-transmitting member 21‧‧‧Shell 22‧‧‧ Light guide plate 27‧‧‧Transmissive substrate 28‧‧‧Semiconductor laminate 36a‧‧‧First reed 36b‧‧‧Second reed 100‧‧‧Light emitting device 100A‧‧‧Light emitting device 100B‧‧‧Light emitting Device 100C‧‧‧Light-emitting device 100D‧‧‧Light-emitting device 200‧‧‧Backlight 251,252‧‧‧Electrode C‧‧‧Center line L‧‧‧Arrangement direction P‧‧‧Outside light-emitting element Q‧‧‧Inside light-emitting element

FIG. 1A is a schematic plan view of the light-emitting device 100 of Embodiment 1. FIG. Fig. 1B is a schematic cross-sectional view of the section taken along the line Ib-Ib in Fig. 1A. FIG. 2 is a schematic plan view of a light-emitting device 100A showing a modification of the light-emitting device 100. FIG. 3A is a schematic plan view of a light-emitting device 100B showing a modification of the light-emitting device 100. FIG. 3B is a schematic plan view of a light-emitting device 100C showing a modification of the light-emitting device 100. FIG. 4A is a schematic plan view of a light-emitting device 100D showing a modification of the light-emitting device 100. Fig. 4B is a schematic cross-sectional view showing the section along the line IIb-IIb of Fig. 4A. FIG. 5A is a schematic plan view showing the backlight 200 of the second embodiment. FIG. 5B is a schematic cross-sectional view showing a modification example of the backlight 200 of the second embodiment.

2‧‧‧Resin package

3‧‧‧Translucent component

6‧‧‧Wire

7‧‧‧Support

10b‧‧‧The first light-emitting element

20g‧‧‧The second light-emitting element

36a‧‧‧First reed

36b‧‧‧Second reed

100‧‧‧Light-emitting device

C‧‧‧Centerline

L‧‧‧Arrangement direction

P‧‧‧Outside light-emitting element

Q‧‧‧Inside light-emitting element

Claims (13)

A light-emitting device having at least three light-emitting elements arranged side by side and a translucent member including phosphors, and the at least three light-emitting elements have two outer light-emitting elements arranged on the outside, and are arranged on the An inner light-emitting element inside the two outer light-emitting elements and having an emission peak wavelength different from the emission peak wavelengths of the two outer light-emitting elements, and the phosphor has a longer emission peak wavelength than the outer light-emitting element and the inner light-emitting element The emission peak wavelength of the two outer light-emitting elements is connected in series with the inner light-emitting element, the emission peak wavelength of each of the two outer light-emitting elements is 430 nm or more and less than 490 nm, and the emission peak wavelength of the inner light-emitting element is The range of 490nm or more and 570nm or less, and the reflectance of the phosphor with respect to the light of the inner light-emitting element is 70% or more on average within the range of the wavelength of the light of the inner light-emitting element. The light-emitting device of claim 1, wherein the peak wavelength of the light emission of the phosphor is in the range of 580 nm or more and 680 nm or less. Such as the light-emitting device of claim 1 or 2, wherein the above-mentioned phosphor is a phosphor whose composition is represented by the following general formula (I) or whose composition is represented by 3.5MgO‧0.5MgF ₂ ‧GeO ₂ : Mn ⁴⁺ At least one of the phosphors: A ₂ MF ₆ : Mn ⁴⁺ (I) (wherein, in the above general formula (I), A is selected from the group consisting of K, Li, Na, Rb, Cs and NH ⁴⁺ At least one element in the group, and M is at least one element selected from the group consisting of group 4 elements and group 14 elements). The light-emitting device of claim 1 or 2, wherein the ratio of the light output of the inner light-emitting element to the outer light-emitting element is in the range of 0.3 or more and 0.7 or less. The light-emitting device of claim 1 or 2, wherein the phosphor contained in the light-transmitting member between the outer light-emitting element and the inner light-emitting element has a content density of that from the upper surface of the inner light-emitting element The height above the upper surface is higher than the height below the upper surface. The light-emitting device of claim 1 or 2, wherein the light-emitting device includes a support, and the two outer light-emitting elements and the inner light-emitting element are placed on the support. The light-emitting device of claim 1 or 2, wherein the distance between the opposing side surfaces of the outer light-emitting element and the inner light-emitting element is 50~150μm The light-emitting device of claim 1 or 2, wherein the side surface of the outer light-emitting element facing the inner light-emitting element and the side surface of the inner light-emitting element facing the outer light-emitting element are arranged so as to be parallel The light-emitting device according to claim 1 or 2, wherein the upper surface of the inner light-emitting element is arranged so that the upper surface of the outer light-emitting element becomes an upper side. The light-emitting device according to claim 1 or 2, wherein the light-transmitting member covers at least a part of the outer light-emitting element and at least a part of the inner light-emitting element. The light-emitting device according to claim 10, wherein the light-transmitting member is in contact with the outer light-emitting element and the inner light-emitting element. The light-emitting device of claim 1 or 2, wherein the inner light-emitting element and the outer light-emitting element are rectangular in plan view, and the long sides of the outer light-emitting element are opposed to the short sides of the inner light-emitting element. A backlight is provided with the light-emitting device according to any one of claims 1 to 12, and a light guide plate with a light-incident part on the side surface, and the light extraction surface of the light-emitting device is arranged opposite to the light-incident part.

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