Light emitting device

Abstract

The light emitting device has a substrate, a plurality of first light emitting elements mounted on the substrate and having first LED dies and emitting light having a first wavelength, and a light guide layer disposed so as to cover the plurality of first light emitting elements and guide the light emitted from the plurality of first light emitting elements, a thickness T between a surface of the first LED dies and a surface of the light guide layer being thicker than a thickness T1 expressed by T1 = LG1 / (2tanθc), where LG1 is a separation distance between the plurality of first LED dies 24, and θc is a critical angle at which the light is emitted from the light guide layer 14 to air.

Description

Technical Field

[0001] This invention relates to a light-emitting device. Background Technology

[0002] A light-emitting device is known, which has a plurality of light-emitting elements modularly arranged on the surface of a substrate and is mounted on a lighting fixture to function as a light source for the lighting fixture. The light-emitting elements included in the light-emitting device are, for example, LED chips covered with phosphors and LED modules encapsulating phosphor-covered LED chips, which mainly emit light from the surface. Furthermore, as a light-emitting device with a plurality of light-emitting elements arranged, a light-emitting device in which a white LED package is disposed in each region of a color filter having multiple regions of different colors is known. In addition, various small light-emitting elements can be used as light-emitting elements, but in this disclosure, an LED chip is described as an example of a light-emitting element.

[0003] Japanese Patent Application Publication No. 2006-86191 discloses a light-emitting device in which a frame-shaped light-shielding member divides the light-emitting surface into multiple regions, and LED chips and light-emitting elements having a phosphor layer covering the LED chips are arranged in the divided regions. Furthermore, Japanese Patent Publication No. 6095479 discloses a light-emitting device in which chip-scale packages (CSPs) emitting warm-colored light and CSPs emitting cool-colored light are arranged alternately, with white reflective resin filling the spaces between the CSPs. Additionally, the CSP, as an example of a light-emitting element, has phosphor resin covering the surface and sides of the LED chips, and electrodes formed on the bottom surface, and has a planar dimension similar to that of the LED chips. Summary of the Invention

[0004] The light-emitting devices described in Japanese Patent Application Publication No. 2006-86191 and Japanese Patent No. 6095479 sometimes have their light-emitting elements perceived as granular by an observer at a distance of about 1 meter when they are illuminated. By placing a diffuser plate between the light-emitting device and the observer, the brightness distribution of the light emitted from the light-emitting device can be made more uniform, preventing the light-emitting elements from being perceived as granular. It is known that the brightness of the light emitted from the light-emitting device can be made more uniform by increasing the distance between the light-emitting device and the diffuser plate and by increasing the diffusion degree of the diffuser plate.

[0005] However, increasing the distance between the light-emitting device and the diffuser plate results in a larger lighting fixture. Furthermore, the increased diffuser plate reduces the luminous efficiency of the lighting fixture. This invention was made in view of the above problems, and its object is to provide a light-emitting device capable of emitting light with a more uniform brightness distribution.

[0006] The light-emitting device disclosed herein includes: a substrate; a plurality of first light-emitting elements mounted on the substrate and having first LED chips that emit light having a first wavelength; and a light-guiding layer disposed to cover the plurality of first light-emitting elements and guide the light emitted from the plurality of first LED chips, wherein the thickness T between the surface of the first light-emitting elements and the surface of the light-guiding layer is thicker than the thickness T1 expressed as T1 = LG1 / (2tanθc), where LG1 is the spacing distance between the plurality of first LED chips and θc is the critical angle at which light is emitted from the light-guiding layer into the air.

[0007] Further, preferably, in the light-emitting device of this disclosure, the thickness T between the surface of the first LED chip and the surface of the light guide layer is thinner than the thickness T2 expressed as T2 = LG2 / (2tanθc), where LG2 is the spacing distance between two first LED chips disposed across one of a plurality of first light-emitting elements.

[0008] Furthermore, preferably, the light-emitting device of this disclosure also has a plurality of second light-emitting elements, which are mounted on a substrate in an alternating manner with a plurality of first light-emitting elements, and have second LED chips that emit light with a second wavelength different from the first wavelength.

[0009] Furthermore, preferably, the light-emitting device of this disclosure also has a white resin disposed between a plurality of first light-emitting elements and a plurality of second light-emitting elements.

[0010] Furthermore, preferably, in the light-emitting device of this disclosure, each of the plurality of first light-emitting elements further includes a first phosphor resin covering a first LED chip, and each of the plurality of second light-emitting elements further includes a second phosphor resin covering a second LED chip, the sides of the first phosphor resin and the second phosphor resin being configured to open outward in an upward direction.

[0011] Furthermore, preferably, the light-emitting device of this disclosure further includes a transparent resin disposed along the side of the first phosphor resin and the second phosphor resin, and disposed in such a way that the side of the transparent resin opens upward and outward.

[0012] Further, preferably, the light-emitting device of this disclosure further includes: a plurality of second light-emitting elements having second LED chips and emitting light having a second wavelength different from the first wavelength; and a plurality of third light-emitting elements having third LED chips and emitting light having a third wavelength different from the first wavelength and the second wavelength, wherein the spacing between the plurality of first LED chips is longer than the spacing between the second LED chips and the third LED chips.

[0013] Furthermore, preferably, the light-emitting device of this disclosure also has a reflective material disposed on a substrate in a manner surrounding a plurality of first light-emitting elements to reflect light emitted from the first light-emitting elements. The light-guiding layer includes a phosphor layer and a transparent layer. The phosphor layer contains a phosphor that absorbs light emitted from the plurality of first light-emitting elements and emits light having a second wavelength different from the first wavelength. The transparent layer is disposed above the phosphor layer and does not contain a phosphor. The spacing LB1 between the first LED chip and the reflective material disposed adjacent to another first light-emitting element is shorter than Ttanθc.

[0014] Furthermore, preferably, in the light-emitting device of this disclosure, the spacing LB2 between the first LED chip and the reflective material disposed adjacent to the reflective material is shorter than Ttanθc.

[0015] Furthermore, preferably, the light-emitting device of this disclosure further includes a diffusion layer configured to cover the light guide layer and diffuse the light guided in the light guide layer.

[0016] Furthermore, preferably, the light-emitting device of this disclosure further includes a diffusion layer configured to cover the light guide layer and diffuse the light guided in the light guide layer.

[0017] Furthermore, preferably, in the light-emitting device of this disclosure, the light guide layer and the diffusion layer are integrated into a frame material, and the diffusion layer is configured to cover the light guide layer and diffuse the light guided in the light guide layer.

[0018] Furthermore, preferably, in the light-emitting device of this disclosure, the plurality of first light-emitting elements are surface-mount type light-emitting elements.

[0019] Furthermore, preferably, the light-emitting device of this disclosure has a control circuit having multiple electronic components mounted on a substrate to control the light emission of the multiple first light-emitting elements.

[0020] The light-emitting device disclosed herein can emit light with a more uniform brightness distribution. Attached Figure Description

[0021] Figure 1 Figure (a) is a schematic diagram illustrating the light-emitting device of the present invention. Figure 1 (b) is a diagram (second one) illustrating the outline of the light-emitting device of the present invention.

[0022] Figure 2 This is a perspective view of the light-emitting device according to the first embodiment.

[0023] Figure 3 It is along Figure 2A cross-sectional view of the light-emitting device along line A-A' shown.

[0024] Figure 4 yes Figure 2 The diagram shows the characteristics of the light-emitting device.

[0025] Figure 5 yes Figure 2 An explanatory diagram (one of) showing the thickness of the transparent layer.

[0026] Figure 6 yes Figure 2 The diagram illustrating the thickness of the transparent layer is shown in Figure 2.

[0027] Figure 7 This is a top view of the light-emitting device according to the second embodiment.

[0028] Figure 8 yes Figure 7 An explanatory diagram (one of) showing the thickness of the transparent layer.

[0029] Figure 9 yes Figure 7 The diagram illustrating the thickness of the transparent layer is shown in Figure 2.

[0030] Figure 10 This is a top view of the light-emitting device according to the third embodiment.

[0031] Figure 11 This is a top view of the light-emitting device according to the fourth embodiment.

[0032] Figure 12 (a) is along Figure 11 The cross-sectional view (a) of the CC-line light-emitting device shown is along the line. Figure 11 shown Figure 11 Cross-sectional view (second one) of the CC line light-emitting device shown.

[0033] Figure 13 (a) is a cross-sectional view of the light-emitting device of the first modified example, (b) is a cross-sectional view of the light-emitting device of the second modified example, (c) is a cross-sectional view of the light-emitting device of the third modified example, (d) is a cross-sectional view of the light-emitting device of the fourth modified example, and (e) is a cross-sectional view of the light-emitting device of the fifth modified example.

[0034] Figure 14 (a) is a cross-sectional view of the light-emitting device of the sixth modification example, (b) is a cross-sectional view of the light-emitting device of the seventh modification example, (c) is a cross-sectional view of the light-emitting device of the eighth modification example, (d) is a cross-sectional view of the light-emitting device of the ninth modification example, (e) is an enlarged view of the part indicated by arrow D in (a), (f) is an enlarged view of the part indicated by arrow E in (b), and (g) is an enlarged view of the part indicated by arrow F in (c).

[0035] Figure 15 This is a cross-sectional view of the light-emitting device of the tenth variation.

[0036] Figure 16 This is a perspective view of the light-emitting device of the eleventh variation.

[0037] Figure 17 This is a perspective view of the light-emitting device in the twelfth variation. Detailed Implementation

[0038] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be noted that the technical scope of the present disclosure is not limited to these embodiments, but covers the claimed invention and its equivalents. Furthermore, in the description of the drawings, the same or corresponding elements are given the same reference numerals, and repeated descriptions are omitted. For ease of explanation, the scale of the components has been appropriately changed.

[0039] (Summary of the light-emitting device disclosed herein)

[0040] Figure 1 (a) is a diagram (one of) illustrating the outline of the light-emitting device of this disclosure. Figure 1 (b) is a diagram (second part) illustrating the outline of the light-emitting device of this disclosure. Figure 1 (a) and Figure 1 (b) is a cross-sectional view of the light-emitting device disclosed herein.

[0041] The light-emitting device 1 includes a substrate 10, a first light-emitting element 11, a second light-emitting element 12, a reflective material 13, and a light-guiding layer 14. The substrate 10 is formed of a component with high thermal conductivity, such as ceramic or aluminum, and is used to mount the first light-emitting element 11 and the second light-emitting element 12. The first light-emitting element 11 and the second light-emitting element 12 are CSP-type light-emitting elements, each having an LED chip and a sealing material such as silicone resin containing a phosphor that converts the wavelength of light emitted from the LED chip to emit light with a first wavelength and a second wavelength. The reflective material 13 is formed of silicone resin containing white particles such as titanium dioxide (TiO2) and is arranged to surround the first light-emitting element 11 and the second light-emitting element 12. The light-guiding layer 14 is a silicone resin that allows light emitted from the first light-emitting element 11 and the second light-emitting element 12 to pass through, and is filled in the area surrounded by the reflective material 13. The light-emitting device 1 emits light with highly uniform brightness by having a thickness T between the surface of the LED chip of the first light-emitting element 11 and the surface of the light-guiding layer 14 that is T1 or more and T2 or less.

[0042] The minimum value T1 of the thickness T between the surface of the LED chip of the first light-emitting element 11 and the surface of the light guide layer 14, when the spacing between the LED chips of the first light-emitting element 11 is LG1, and the critical angle when light is emitted from the light guide layer 14 into the air is θc, is expressed as the following formula.

[0043] T1=LG1 / (2tanθc) (1)

[0044] Furthermore, the maximum value T2 of the thickness T between the surface of the LED chip of the first light-emitting element 11 and the surface of the light guide layer 14 is expressed as follows when the interval between the LED chips of two first light-emitting elements 11 arranged with one first light-emitting element 11 in between is LG2.

[0045] T2=LG2 / (2tanθc) (2)

[0046] The thickness T between the surface of the LED chip of the first light-emitting element 11 and the surface of the light guide layer 14 is preferably more than 1 mm and less than 1.5 mm.

[0047] In the light-emitting device 1, by making the thickness T between the surface of the LED chip of the first light-emitting element 11 and the surface of the light guide layer 14 T1 or more, light emitted from the first light-emitting element 11 is emitted across the entire surface of the light guide layer 14. Furthermore, by making the thickness T between the surface of the LED chip of the first light-emitting element 11 and the surface of the light guide layer 14 T2 or less, it is possible to prevent the light guide layer 14 from becoming too thick and thus reducing luminous efficiency, and it is also possible to suppress increases in manufacturing costs. The height of the LED chip of the second light-emitting element 12 is the same as the height of the LED chip of the first light-emitting element 11, and the spacing between the LED chips of the second light-emitting element 12 is the same as the spacing between the LED chips of the first light-emitting element 11.

[0048] The light-emitting device 1 uses a CSP type light-emitting element, but it can also be a chip-on-board (COB) type light-emitting device with LED chips mounted on a substrate, or a light-emitting device with a surface-mount (SMD) type light-emitting element.

[0049] The light-emitting device 2 differs from the light-emitting device 1 in that it has a first light-emitting element 15 and a light-guiding layer 16 instead of a first light-emitting element 11, a second light-emitting element 12, and a light-guiding layer 14. The first light-emitting element 15 is an LED chip that emits light with a first wavelength. The light-guiding layer 16 includes a phosphor layer 17 and a transparent layer 18. The phosphor layer 17 is a silicone resin containing a phosphor that converts the wavelength of the light emitted from the first light-emitting element 15 to emit light with a second wavelength. The transparent layer 18 is a silicone resin that allows light emitted from the phosphor contained in the first light-emitting element 15 and the phosphor layer 17 to pass through. The light-emitting device 2 suppresses the generation of yellow rings by making the thickness T between the surface of the first light-emitting element 15 and the surface of the light-guiding layer 16 T3 or more and T4 or less.

[0050] The minimum value of the thickness T between the surface of the first light-emitting element 15 and the surface of the light guide layer 16, when the distance between the first light-emitting element 15 and the reflective material 13 arranged adjacent to the reflective material 13 is LB1, is expressed as the following formula.

[0051] T3=LB1 / tanθc (3)

[0052] That is, the distance LB1 between the first light-emitting element 15 and the reflective material 13 arranged adjacent to the reflective material 13 is shorter than Ttanθc. In addition, the maximum value T4 of the thickness T between the surface of the first light-emitting element 15 and the surface of the light guide layer 16, when the distance between the first light-emitting element 15 and the reflective material 13 arranged adjacent to another first light-emitting element 15 is LB2, is expressed as follows.

[0053] T4=LB2 / tanθc (4)

[0054] That is, the distance LB2 between the first light-emitting element 15 and the reflective material 13, which are arranged adjacent to each other, is longer than Ttanθc.

[0055] In the light-emitting device 2, by making the thickness T between the surface of the first light-emitting element 15 and the surface of the light-guiding layer 16 T3 or more, light emitted from the first light-emitting element 15, which is disposed adjacent to the reflective material 13, is emitted towards the outer edge of the surface of the light-guiding layer 16, which is embedded within the reflective material 13. In the light-emitting device 2, light emitted from the first light-emitting element 15 is emitted towards the outer edge of the surface of the light-guiding layer 14, which is embedded within the reflective material 13. Therefore, only light emitted from the phosphor contained in the phosphor layer 17 is emitted towards the outer edge of the surface of the light-guiding layer 16, preventing the formation of a yellow ring. Furthermore, by setting the thickness T between the surface of the first light-emitting element 15 and the surface of the light-guiding layer 16 to T4 or less in the light-emitting device 2, it is possible to prevent the light-emitting efficiency from decreasing due to the increased thickness of the light-guiding layer 16, and to suppress the increase in manufacturing costs.

[0056] (Structure and function of the light-emitting device in the first embodiment)

[0057] Figure 2 This is a perspective view of the light-emitting device according to the first embodiment. Figure 3 It is along Figure 2 A cross-sectional view along line A-A'. The light-emitting device 3 has a substrate 20, eight first light-emitting elements 21 and second light-emitting elements 22 mounted on the surface of the substrate 20, and a sheet-like light guide layer 23 disposed above the first light-emitting elements 21 and second light-emitting elements 22. More preferably, the upper surface of the sheet-like light guide layer 23 is flat. The manufacturing method of the light-emitting device 3 is known, therefore a detailed description is omitted.

[0058] The substrate 20 is an insulating substrate with high reflectivity and thermal conductivity, such as ceramic. Power electrodes 20a are formed at one corner, and screw-fixing notches 20b are formed at the other corner. The first light-emitting element 21 and the second light-emitting element 22 are arranged in a 4×4 matrix on the surface of the substrate 20. Furthermore, the first light-emitting element 21 and the second light-emitting element 22 are arranged in a checkered pattern. The light guide layer 23 is formed of silicone resin and is configured to cover the first light-emitting element 21 and the second light-emitting element 22. The light guide layer 23 does not contain a diffusion material, also known as a filler. Additionally, in... Figure 2 The wiring connecting the power supply electrode 20a to the first light-emitting element 21 and the second light-emitting element 22, as well as the wiring between the first light-emitting element 21 and the second light-emitting element 22, is omitted.

[0059] The first light-emitting element 21 and the second light-emitting element 22 have a rectangular planar shape of 1.7mm × 1.7mm and include an LED chip 24, a fluorescent resin 25, and a reflective frame 26. The LED chip 24 and fluorescent resin 25 included in the first light-emitting element 21 are also referred to as the first LED chip and the first fluorescent resin, and the LED chip 24 and fluorescent resin 25 included in the second light-emitting element 22 are also referred to as the second LED chip and the second fluorescent resin. The LED chip 24 has a rectangular planar shape of 1.0mm × 1.0mm and is a blue diode, having a sapphire substrate disposed on the top, a light-emitting layer formed below the sapphire substrate, and an anode electrode and a cathode electrode disposed on the bottom surface. The dominant wavelength of the blue light emitted from the LED chip 24 is in the range between 445nm and 495nm, and in one example, 450nm. The fluorescent resin 25 is a silicone resin containing phosphors such as YAG, covering the surface and sides of the LED chip 24, and performing wavelength conversion on a portion of the light emitted by the LED chip 24. The reflective frame 26 is a silicone resin containing reflective particles such as titanium dioxide, surrounding the fluorescent resin 25 so that the light emitted from the LED chip 24 is directed upwards. The fluorescent resin 25 of the first light-emitting element 21 and the second light-emitting element 22 contains different amounts of phosphor, emitting light with a first wavelength and light with a second wavelength different from the first wavelength. The light with the first wavelength emitted from the first light-emitting element 21 is, for example, cool-colored light with a color temperature of 5000K, while the light with the second wavelength emitted from the second light-emitting element 22 is, for example, warm-colored light with a color temperature of 2700K.

[0060] The first light-emitting element 21 and the second light-emitting element 22 are flip-chip mounted on the surface of the substrate 20. The light guide layer 23 is bonded to the surfaces of the first light-emitting element 21 and the second light-emitting element 22 by an adhesive material.

[0061] Figure 4 This is a characteristic diagram showing the relationship between the brightness of the front side of the light-emitting device 3 and the thickness of the light guide layer 23. Along... Figure 2 The A-A' line shown measures the front brightness of the light-emitting device 3, and adjusts the brightness of the light emitted from the first light-emitting element 21 and the second light-emitting element 22 to be the same.

[0062] Figure 4 The vertical axis represents the peak brightness of the front light and the variation at the bottom, while the horizontal axis represents the thickness (mm) of the light guide layer 23. The front brightness of the light emitted from the light-emitting device 3 is greatest directly above the first light-emitting element 21 and the second light-emitting element 22, and minimum at the midpoint between the first light-emitting element 21 and the second light-emitting element 22. Figure 4In the figure, curve W401 represents the difference between the peak (maximum) and the bottom (minimum) values ​​of the front brightness, i.e., the variation range. The variation range of the front brightness shown by curve W401 will be normalized to 100% when the thickness of the light guide layer 23 is zero, i.e., when there is no light guide layer 23.

[0063] The variation in the front brightness of the light emitted from the first light-emitting element 21 and the second light-emitting element 22 decreases as the light guide layer 23 becomes thicker. If the thickness of the light guide layer 23 exceeds 1 mm, the variation becomes smaller.

[0064] Figure 5 This is an illustrative diagram illustrating an example of the lower limit of the thickness between the surface of the LED chip 24 of the first light-emitting element 21 and the surface of the light guide layer 23, along... Figure 2 A cross-sectional view of the light-emitting device 3 along line A-A' shown. Figure 5 The distance between the first light-emitting element 21 and the second light-emitting element 22 is shown in an exaggerated manner. Figure 5 In the diagram, the positions of the surface of the light guide layer 23 are designated as first position 23a, second position 23b, and third position 23c. First position 23a is the position of the surface of the light guide layer 23 when the lower limit value is reached, second position 23b is the position of the surface of the light guide layer 23 when the lower limit value is reached, and third position 23c is the position of the surface of the light guide layer 23 when the lower limit value is reached.

[0065] The distance between the LED chip 24 of the first light-emitting element 21 and the LED chip 24 of the adjacent second light-emitting element 22 is LG1, the distance between the LED chips 24 of the adjacent first light-emitting element 21 is LG2, and the distance between the LED chips 24 of the first light-emitting element 21 and the LED chips 24 of the second light-emitting element 22, which are separated by the first light-emitting element 21 and the second light-emitting element 22, is LG3. Light ray P1 is emitted from the side of the first light-emitting element 21 opposite to the second light-emitting element 22 and incident on the surface of the light guide layer 23 at a critical angle θc. Light ray P2 is emitted from the side of the second light-emitting element 22 opposite to the first light-emitting element 21 and incident on the surface of the light guide layer 23 at a critical angle θc.

[0066] The thickness between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 located at the first position 23a is represented by T1. The thickness T1 between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 is expressed by the following formula based on the critical angle θc when light is emitted from the light guide layer 23 into the air and the distance LG1 between the first light-emitting element 21 and the second light-emitting element 22.

[0067] T1=LG1 / (2tanθc) (1)

[0068] When the thickness between the surface of the LED chip 24 of the first light-emitting element 21 and the surface of the light guide layer 23 is T1, light rays P1 and P2 intersect at the intersection 27 where the centerline between the LED chip 24 of the first light-emitting element 21 and the surface of the light guide layer 23 intersects.

[0069] When the surface of the light guide layer 23 is at position 23b, and the thickness between the surface of the LED chips 24 of the first and second light-emitting elements 21 and the surface of the light guide layer 23 is greater than T1, no dark line is generated. When the thickness between the surface of the LED chips 24 of the first and second light-emitting elements 21 and the surface of the light guide layer 23 is greater than T1, light is emitted from the surface of the light guide layer 23 to the outside at the intersection 27. On the other hand, when the surface of the light guide layer 23 is at position 23c, and the thickness between the surface of the LED chips 24 of the first and second light-emitting elements 21 and the surface of the light guide layer 23 is less than T1, a band-shaped dark area is generated. When the thickness between the surface of the LED chips 24 of the first and second light-emitting elements 21 and the surface of the light guide layer 23 is less than T1, light does not emit from the surface of the light guide layer 23 to the outside near the intersection 27.

[0070] When the thickness between the surface of the LED chip 24 of the first light-emitting element 21 and the surface of the light guide layer 23 is T1 or more, light is emitted from the entire surface of the light guide layer 23, and the uniformity of the brightness of the light emitted from the light-emitting device 3 is improved. When the thickness between the surface of the LED chip 24 of the first light-emitting element 21 and the surface of the light guide layer 23 is T1 or more, light with high brightness uniformity is emitted. Therefore, by combining it with a diffuser plate with low diffusivity, the brightness of the light emitted from the lighting fixture equipped with the light-emitting device 3 is further uniformized.

[0071] Figure 6 This diagram illustrates the optimal and upper limit values ​​of the thickness T between the surface of the LED chip 24 of the first light-emitting element 21 and the surface of the light guide layer 23. It is along... Figure 2 A cross-sectional view of the light-emitting device 3 along line A-A' shown.

[0072] Light ray P1 is emitted from the edge of the LED chip 24 of the first light-emitting element 21 opposite to the second light-emitting element 22, and incident on the surface of the light guide layer 23 at a critical angle θc. Light ray P3 is emitted from the edge of the LED chip 24 of the first light-emitting element 21 adjacent to the LED chip 24 from which light ray P1 is emitted, separated by the second light-emitting element 22, and incident on the surface of the light guide layer 23 at a critical angle θc. When the surface of the light guide layer 23 is at the fourth position 23d, and the thickness between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 is T2, light rays P1 and P3 intersect at the intersection 28 on the surface of the light guide layer 23.

[0073] The thickness T2 between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 is expressed as follows, based on the critical angle θc when light is emitted from the light guide layer 23 into the air and the spacing distance LG2 between the LED chips 24 of the first light-emitting element 21 adjacent to the second light-emitting element 22.

[0074] T2=LG2 / (2tanθc) (2)

[0075] In the light-emitting device 3, light emitted directly upward from the second light-emitting element 22 is emitted from the surface of the light guide layer 23 near the intersection 28 on the surface of the light guide layer 23. The light-emitting device 3 emits light uniformly to the outside from the entire surface of the light guide layer 23.

[0076] The refractive index of the light guide layer 23, formed of silicone resin, is 1.4, and the critical angle θc is approximately 45°. Furthermore, the distance LG1 between the LED chips 24 of the first light-emitting element 21 and the LED chips 24 of the second light-emitting element 22 is 0.3 mm, and the distance LG2 between the LED chips 24 of the first light-emitting element 21 is 2.3 mm. When the critical angle θc is 45°, the distance LG1 is 0.3 mm, and the distance LG2 is 2.3 mm, T1 calculated by equation (1) is 0.15 mm. Additionally, T2 calculated by equation (2) is 1.15 mm. In curve W401, when the thickness T of the light guide layer 23 exceeds 1 mm, the change, i.e., the attenuation, becomes smaller and saturates. For the variation range of the front brightness corresponding to curve W401, the thickness T between the surface of the LED chips 24 of the first and second light-emitting elements 21 and the surface of the light guide layer 23 saturates at approximately 80% of T2.

[0077] When the thickness between the surface of the LED chip 24 of the first light-emitting element 21 and the surface of the light guide layer 23 is 0.15 mm, i.e., T1, the value of curve W401 is approximately 95%. When the thickness between the surface of the LED chip 24 of the first light-emitting element 21 and the surface of the light guide layer 23 is 1.15 mm, i.e., T2, the value of curve W401 is approximately 75%.

[0078] In the light-emitting device 3, when the thickness T between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 is T1 or more, the uniformity of the brightness of the emitted light is improved. However, when the thickness T between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 is near T1, in order to further improve the uniformity of the brightness of the emitted light, it is preferable to have a diffusion layer above the light guide layer 23.

[0079] Furthermore, if the thickness T of the light guide layer 23 increases, the luminous efficiency decreases, and the operability also decreases. On the other hand, when the thickness T between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 is 1.0 mm or more, the variation range of the front brightness becomes saturated. The upper limit of the thickness between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 can be T2' = LG3 / (2tanθc). In the light-emitting device 3, the thickness between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 is preferably T1 or more and T2' or less. Specifically, the thickness T between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 is preferably 1.0 mm or more and 1.5 mm or less.

[0080] To suppress the decrease in luminous efficiency, the light guide layer 23 is preferably thinner. Therefore, the optimal value of the thickness T between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 is T2. When the thickness between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 is 0.5 mm, that is, the variation of the front brightness starts to decrease from around 0.5T2. Therefore, the thickness T is more preferably 0.5T2 or more and T2' or less.

[0081] Already referenced Figure 4-6The improvement in brightness uniformity is described. However, by adjusting the relative intensity of the light emitted from the first light-emitting element 21 and the second light-emitting element 22, the light-emitting device 3 is able to emit light with an intermediate color between the light emitted from the first light-emitting element 21 and the second light-emitting element 22. It is desirable to improve the distribution, i.e., the color mixing, of the light emitted from the first light-emitting element 21 and the second light-emitting element 22 on the surface of the light guide layer 23.

[0082] (Structure and function of the light-emitting device in the second embodiment)

[0083] Figure 7 This is a top view of the light-emitting device according to the second embodiment.

[0084] The number of first light-emitting elements 21 and second light-emitting elements 22 installed in the light-emitting device 4 is different from that in the light-emitting device 3. The structure and function of the light-emitting device 4, except for the number of first light-emitting elements 21 and second light-emitting elements 22 installed, are the same as those of the light-emitting device 3, so detailed descriptions are omitted here.

[0085] The first light-emitting element 21 and the second light-emitting element 22 are arranged in a 7×7 matrix on the surface of the substrate 20. In addition, the first light-emitting element 21 and the second light-emitting element 22 are arranged in a checkered pattern on the surface of the substrate 20.

[0086] Figure 8 This is an explanatory diagram showing the lower limit of the thickness T between the surface of the LED chip 24 of the first light-emitting element 21 and the surface of the light guide layer 23, along... Figure 7 A cross-sectional view of the light-emitting device 4 of the B-B' line.

[0087] The distance between LED chips 24 of adjacent first light-emitting elements 21 separated by a second light-emitting element 22 is LG1. The distance between LED chips 24 of two first light-emitting elements 21 arranged with one first light-emitting element 21 and two second light-emitting elements 22 separated by a second light-emitting element 22 is LG2. Furthermore, the distance between LED chips 24 of first light-emitting elements 21 arranged with two first light-emitting elements 21 and three second light-emitting elements 22 separated by a third light-emitting element 22 is LG3. Light ray P1 is emitted from the side of the LED chip 24 of the first light-emitting element 21 opposite to the second light-emitting element 22 and incident on the surface of the light guide layer 23 at a critical angle θc. Light ray P2 is emitted from the side of the LED chip 24 of the first light-emitting element 21 adjacent to the first light-emitting element 21 from which light ray P1 is emitted, opposite to the second light-emitting element 22, and incident on the surface of the light guide layer 23 at a critical angle θc.

[0088] The thickness between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 at the first position 23a is represented by T1. The thickness T1 between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 has the relationship shown in Equation (1) with respect to the critical angle θc when light is emitted from the light guide layer 23 into the air and the distance LG1 between the LED chips 24 of the first light-emitting element 21 adjacent to the second light-emitting element 22.

[0089] When the position on the surface of the light guide layer 23 is the second position 23b, and the thickness between the surface of the LED chips 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 is T1 or more, the light emitted from the first light-emitting element 21 and the second light-emitting element 22 mixes colors across the entire surface of the light guide layer 23. When the position on the surface of the light guide layer 23 is the third position 23c, and the thickness between the surface of the LED chips 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 is thinner than T1, the light emitted from the first light-emitting element 21 and the second light-emitting element 22 will not mix colors near the intersection 27.

[0090] Figure 9 This diagram illustrates the optimal and upper limit values ​​of the thickness T between the surface of the LED chip 24 of the first light-emitting element 21 and the surface of the light guide layer 23. It is along... Figure 7 A cross-sectional view of the light-emitting device 4 along the B-B' line shown.

[0091] Light ray P1 is emitted from the side of the LED chip 24 of the first light-emitting element 21 opposite to the second light-emitting element 22, and incident on the surface of the light guide layer 23 at a critical angle θc. Light ray P3 is emitted from the side of the LED chip 24 of the first light-emitting element 21 adjacent to the first light-emitting element 21 from which light ray P1 is emitted, opposite to the second light-emitting element 22, and incident on the surface of the light guide layer 23 at a critical angle θc. When the surface of the light guide layer 23 is at the fourth position 23d, and the thickness between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 is T2, light rays P1 and P3 intersect at the intersection 28 on the surface of the light guide layer 23.

[0092] The thickness T2 between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 is related to the critical angle θc when light is emitted from the light guide layer 23 into the air, and the spacing LG2 between the LED chips 24 of the first light-emitting element 21 that are adjacent to each other with one first light-emitting element 21 and two second light-emitting elements 22, as expressed by equation (2). In order to suppress the reduction of luminous efficiency, the light guide layer 23 is preferably thinner. Therefore, the optimal value of the thickness T between the surface of the LED chip 24 of the first light-emitting element 21 and the second light-emitting element 22 and the surface of the light guide layer 23 is T2.

[0093] The light-emitting device 4 can improve the color mixing properties of the light emitted from the first light-emitting element 21 and the second light-emitting element 22 by making the thickness between the surface of the LED chip 24 of the first light-emitting element 21 and the surface of the light guide layer 23 above T1 and below T2.

[0094] (Structure and function of the light-emitting device in the third embodiment)

[0095] Figure 10 This is a top view of the light-emitting device according to the third embodiment. The difference between the light-emitting device 5 and the light-emitting device 3 is that the light-emitting device 5 has a first light-emitting element 31, a second light-emitting element 32, and a third light-emitting element 33 arranged in a triangle, each emitting light with wavelengths corresponding to RGB colors, instead of the first light-emitting element 21 and the second light-emitting element 22. The structure and function of the constituent elements of the light-emitting device 5, except for the first light-emitting element 31, the second light-emitting element 32, and the third light-emitting element 33, are the same as the structure and function of the constituent elements of the light-emitting device 3, which are labeled with the same symbols; therefore, detailed descriptions are omitted here.

[0096] The first light-emitting element 31 is formed of a blue LED chip 24 and a silicone resin containing a phosphor such as CASN that emits red light and covering the blue LED chip, emitting red light. The dominant wavelength of the red light emitted from the first light-emitting element 31 is in the range of 600nm to 680nm, and in one example, it is 660nm. The second light-emitting element 32 is formed of a blue LED chip 24 and a silicone resin containing a phosphor such as YAG that emits green light and covering the blue LED chip 24, emitting green light. The dominant wavelength of the green light emitted from the second light-emitting element 32 is in the range of 500nm to 570nm, and in one example, it is 550nm. The third light-emitting element 33 is formed of a blue LED chip 24 and emits blue light. The dominant wavelength of the blue light emitted from the third light-emitting element 33 is in the range of 445nm to 495nm, and in one example, it is 450nm. In addition, the LED chip 24 included in the first light-emitting element 31 is also referred to as the first LED chip, the LED chip 24 included in the second light-emitting element 32 is also referred to as the second LED chip, and the LED chip 24 included in the third light-emitting element 33 is also referred to as the third LED chip.

[0097] The distance between the LED chips 24 of adjacent first light-emitting elements 31 is LG1, and the distance between the LED chips 24 of first light-emitting elements 31 arranged with one first light-emitting element 31 between them is LG2. The thickness T between the surface of the LED chips 24 of the first light-emitting element 31, the second light-emitting element 32, and the third light-emitting element 33 and the surface of the light guide layer 23 is T1 or higher, calculated by formula (1) based on the distance LG1 between the LED chips 24 of adjacent first light-emitting elements 31. Alternatively, it is T2 or lower, calculated by formula (2) based on the distance LG2 between two first light-emitting elements 31 arranged with one first light-emitting element 31 between them and the surface of the light guide layer 23. Alternatively, the thickness T can also be a value of T1 or higher, calculated by formula (1) based on the distance between the LED chips 24 of adjacent first light-emitting elements 31 arranged with the shortest distance in the direction between the LED chips 24 of adjacent first light-emitting elements 31. Alternatively, the thickness T can be a value below T2 calculated by Equation (2) based on the distance between the LED chips 24 of the adjacent first light-emitting elements 31 arranged in the direction of longest distance between adjacent LED chips 24.

[0098] Alternatively, the thickness T can be a value of T1 or higher calculated using equation (1) based on the distance between the LED chips 24 of the adjacent first light-emitting element 31, second light-emitting element 32, and third light-emitting element 33 in the direction with the longest distance between them. Alternatively, the thickness T can be a value of T2 or lower calculated using equation (2) based on the distance between the LED chips 24 of the adjacent first light-emitting element 31, second light-emitting element 32, and third light-emitting element 33 in the direction with the shortest distance between them. In addition, the light-emitting device 5 may also have a diffusion layer, which is arranged to cover the light guide layer 23 and diffuses the light guided in the light guide layer 23.

[0099] (Structure and function of the light-emitting device in the fourth embodiment)

[0100] Figure 11 This is a top view of the light-emitting device according to the fourth embodiment. Figure 12 (a) is along Figure 11 A cross-sectional view (one) of the CC-line light-emitting device shown. Figure 12 (b) is along Figure 11 shown Figure 11 The diagram shows a cross-sectional view (second one) of the CC-line light-emitting device. The light-emitting device 6 includes a substrate 40, a first light-emitting element 41, a reflective material 42, a light-guiding layer 43, and a diffusion layer 44. The substrate 40 has the same structure and function as the substrate 20. The first light-emitting element 41 is formed from a blue LED chip and emits blue light. The dominant wavelength of the blue light emitted from the first light-emitting element 41 is in the range of 445nm to 495nm, and in one example, 450nm. The reflective material 42 is formed from a silicone resin containing white particles such as titanium oxide and is arranged to surround the first light-emitting element 41. The light-guiding layer 43 includes a phosphor layer 45 and a transparent layer 46. The phosphor layer 45 is a silicone resin containing phosphors such as YAG that absorb light emitted from the first light-emitting element 41 and emit yellow light. The transparent layer 46 is a silicone resin that allows light emitted from the phosphors contained in the first light-emitting element 15 and the phosphor layer 17 to pass through.

[0101] The diffusion layer 44 is preferably composed of a diffusing agent containing fillers in silicone resin, a sheet containing diffusing particles, coated microparticle powder, or a prism, and preferably exhibits high forward scattering and low backward scattering. The diffusion layer 44 can be a light-transmitting plate with a textured surface on either the front or back. The diffusion layer 44 improves the brightness and color mixing uniformity on the surface of the transparent layer 46. Furthermore, since light is emitted from the entire surface of the diffusion layer 44, when the light-emitting device 6 is installed in a lighting fixture, the diffusion degree of the diffusing component in the lighting fixture can be reduced, suppressing a decrease in luminous efficiency. Alternatively, the diffusion layer 44 can be omitted.

[0102] The thickness T between the surface of the first light-emitting element 41 and the surface of the light guide layer 43 is T1 or higher, calculated by Equation (1) based on the distance between adjacent first light-emitting elements 41. Alternatively, it is T2 or lower, calculated by Equation (2) based on the distance between two first light-emitting elements 41 arranged with one first light-emitting element 41 in between.

[0103] The thickness Tk of the diffusion layer 44 is preferably greater than 0 mm and less than the thickness T between the surface of the first light-emitting element 41 and the surface of the light guide layer 43. More preferably, the thickness Tk of the diffusion layer 44 is 0.3 times thicker than the thickness T between the surface of the first light-emitting element 41 and the surface of the light guide layer 43 and 0.5 times thinner than the thickness T between the surface of the LED chip of the first light-emitting element 41 and the surface of the light guide layer 43.

[0104] When the thickness T between the surface of the first light-emitting element 41 and the surface of the light guide layer 43 is 1.0 mm or more and 1.5 mm or less, if the thickness of the diffuser layer 44 is set to 0.5 mm, the variation in the front brightness of the light from the first light-emitting element 41 is 40%, which is a good value. When the light guide layer 43 is not provided and the thickness of the diffuser layer 44 is 1.25 mm, the total beam of light from the first light-emitting element 41 is reduced by 7.5% compared to the case without the diffuser layer 44. On the other hand, when the thickness of the light guide layer 43 is 1.25 mm and the thickness of the diffuser layer 44 is 0.5 mm, the total beam of light from the first light-emitting element 41 is reduced by 3.9% compared to the case without the diffuser layer 44, and the reduction in the total beam can be suppressed compared to the case without the light guide layer 43. When the thickness T between the surface of the first light-emitting element 41 and the surface of the light guide layer 43 is 1.0 mm or more and 1.5 mm or less, if the thickness of the diffusion layer 44 is 0.5 mm, then the thickness Tk of the diffusion layer 44 is within the range of being 0.3 times thicker and 0.5 times thinner than the thickness T. By making the thickness Tk of the diffusion layer 44 0.3 times thicker and 0.5 times thinner than the thickness T, the variation in the front brightness of the light from the first light-emitting element 41 can be reduced, and the reduction in the total beam can be suppressed.

[0105] The yellow ring is a phenomenon where the blue light emitted from the first light-emitting element 41 and the yellow light emitted from the phosphor contained in the phosphor layer 45 do not mix, and a yellow ring is generated near the inner wall of the reflective material 42.

[0106] exist Figure 12 In (a), the distance between the first light-emitting element 41 and the reflective material 42, which are arranged adjacent to the reflective material 42, is LB1. The light ray P4 is emitted from the side of the first light-emitting element 41 opposite to the reflective material 42 and is incident on the surface of the light guide layer 23 at a critical angle θc. The minimum value T3 of the thickness T between the surface of the first light-emitting element 41 and the surface of the light guide layer 43 is expressed by the following formula.

[0107] T3=LB1 / tanθc (3)

[0108] That is, the spacing LB1 between the first light-emitting element 41 and the reflective material 42, which are arranged adjacent to the reflective material 42, is shorter than Ttanθc. The spacing LB1 is the minimum distance between the angle of the first light-emitting element 41 that is not surrounded by other first light-emitting elements 41 on at least two sides and the reflective material 42.

[0109] In addition, Figure 12 In (b), the distance between the first light-emitting element 41 and the reflective material 42, which are adjacent to each other with another first light-emitting element 41, is LB2. Light P5 is emitted from the side of the first light-emitting element 41 opposite to the reflective material 42, and is incident on the surface of the light guide layer 23 at a critical angle θc. The maximum value T4 of the thickness T between the surface of the first light-emitting element 41 and the surface of the light guide layer 43, when the distance between the first light-emitting element 41 and the reflective material 42, which are adjacent to each other with another first light-emitting element 41, is expressed as follows.

[0110] T4=LB2 / tanθc (4)

[0111] That is, the distance LB2 between the first light-emitting element 41 and the reflective material 42, which are arranged adjacent to each other, is longer than Ttanθc.

[0112] (A modified example of a light-emitting device)

[0113] Figure 13 (a) is a cross-sectional view of the light-emitting device of the first modified example. Figure 13 (b) is a cross-sectional view of the light-emitting device in the second modified example. Figure 13 (c) is a cross-sectional view of the light-emitting device of the third modified example. Figure 13(d) is a cross-sectional view of the light-emitting device in the fourth modified example. Figure 13 (e) is a cross-sectional view of the light-emitting device of the fifth variation. Figure 13 (a) to (e) of 13 are along Figure 2 The cross-sectional view corresponding to the cross-sectional view of line A-A' shown.

[0114] The difference between the first modified light-emitting device 7a and the light-emitting device 3 is that it has a reflective material 50 and a light-guiding layer 51 instead of a light-guiding layer 23. The structure and function of the constituent elements of the light-emitting device 7a other than the reflective material 50 and the light-guiding layer 51 are the same as those of the constituent elements of the light-emitting device 3, which are marked with the same symbols, so detailed descriptions are omitted here.

[0115] Like reflective material 42, reflective material 50 is formed of silicone resin containing white particles such as titanium dioxide, and is arranged to surround the first light-emitting element 21 and the second light-emitting element 22. Light guide layer 51 is silicone resin filled in the area surrounded by reflective material 50, allowing light emitted from the first light-emitting element 21 and the second light-emitting element 22 to pass through. Light guide layer 51 is formed by filling the reflective material 50 with resin material before curing, and then curing the resin material before curing by heating the substrate 20. Because light-emitting device 7a has reflective material 50, it can emit highly directional light from the surface of light guide layer 51. Alternatively, although light-emitting devices 3-5 do not have reflective material, they can be further configured with reflective material that surrounds multiple first light-emitting elements on the substrate and reflects light emitted from the first light-emitting elements.

[0116] The difference between the light-emitting device 7b and the light-emitting device 7a in the second variation is that it has a diffusion layer 52. The structure and function of the constituent elements of the light-emitting device 7b other than the diffusion layer 52 are the same as those of the constituent elements of the light-emitting device 7a, which are marked with the same symbols, so detailed descriptions are omitted here.

[0117] Like diffusion layer 44, diffusion layer 52 is a sheet containing diffusing particles, coated microparticle powder, or a prism, etc., and is connected to light guide layer 51 by adhering its back side to the surface of light guide layer 51. The light-emitting device 7b, by having diffusion layer 52, can emit light with high brightness uniformity and color mixing. It should be noted that light-emitting devices 3-5 do not have diffusion layers, but they can further employ diffusion layers configured to cover the light guide layer and diffuse the light guided in the light guide layer.

[0118] The difference between the third variation of the light-emitting device 7c and the light-emitting device 7b is that it has a diffusion layer 53 instead of a diffusion layer 52. The structure and function of the constituent elements of the light-emitting device 7c other than the diffusion layer 53 are the same as those of the constituent elements of the light-emitting device 7b, which are marked with the same symbols, so detailed descriptions are omitted here.

[0119] The difference between diffusion layer 53 and diffusion layer 52 is that diffusion portion 53a is formed above the first light-emitting element 21 and the second light-emitting element 22. By forming diffusion portion 53a above the first light-emitting element 21 and the second light-emitting element 22, which emit light with high brightness, the light-emitting device 7c can effectively mix high-brightness light, suppress the reduction of luminous efficiency, and emit light with high uniformity of brightness and high color mixing.

[0120] The difference between the light-emitting device 7d and the light-emitting device 7b in the fourth variation is that the light-emitting device 7d includes a light guide layer 54 and a diffusion layer 55 instead of a light guide layer 51 and a diffusion layer 52. The structure and function of the constituent elements of the light-emitting device 7d, except for the light guide layer 54 and the diffusion layer 55, are the same as those of the constituent elements of the light-emitting device 7b, which are marked with the same symbols, so detailed descriptions are omitted here.

[0121] The difference between light guide layer 54 and light guide layer 51 is that the surface of light guide layer 54 is curved into a convex shape. The difference between diffuser layer 55 and diffuser layer 53 is that diffuser layer 55 has a curved shape that protrudes upward from the center, according to the surface shape of light guide layer 54. In the light-emitting device 7d, since light guide layer 54 and diffuser layer 55 have a lens shape that protrudes upward from the center, highly directional light can be emitted.

[0122] The fifth variation of the light-emitting device 7e differs from that of the light-emitting device 7a in that it has a frame material 56 and an adhesive layer 57 instead of a reflective material 50 and a light-guiding layer 51. The structure and function of the constituent elements of the light-emitting device 7e, other than the frame material 56 and the adhesive layer 57, are the same as those of the constituent elements of the light-emitting device 7a, which are marked with the same symbols, so detailed descriptions are omitted here.

[0123] The frame material 56 has a diffuser frame 58 and a light guide portion 59. The diffuser frame 58 has a side portion arranged to surround the first light-emitting element 21 and the second light-emitting element 22, and an upper portion covering the top of the first light-emitting element 21 and the second light-emitting element 22, diffusing the light emitted from the first light-emitting element 21 and the second light-emitting element 22 and emitting it outward. Since the thickness of the side portion covering the diffuser frame 59 is greater than the thickness of the diffuser portion covering the surface of the light guide portion, it functions as a reflective frame. The light guide portion 59 is formed of a component such as silicone resin that transmits light emitted from the first light-emitting element 21 and the second light-emitting element 22, and is integrated with the diffuser frame 58. The adhesive layer 57 is formed of a component such as silicone resin that transmits light emitted from the first light-emitting element 21 and the second light-emitting element 22, and is an adhesive component that bonds the frame material 56 to the substrate 20.

[0124] Since the frame material 56 of the light-emitting device 7e has a diffuser frame 58 and a light guide portion 59, a reflective material, also known as a blocking material, is not required, thus simplifying the manufacturing process. Furthermore, in the light-emitting device 7e, since the diffuser frame 58 and the light guide portion 59 are integrated by the frame material 56, the thickness of the light guide portion 59 can be manufactured uniformly. Additionally, in the light-emitting device 7e, a diffusion layer with a desired diffusion degree can be easily formed by adjusting the diffusion degree of the diffuser frame 58. While the frame material 56 functions as a reflective frame by thickening the side surface of the light guide portion 59, in the light-emitting layer device of this embodiment, a material with high reflectivity can also be disposed on the side surface of the light guide portion 59.

[0125] Figure 14 (a) is a cross-sectional view of the light-emitting device in the sixth modified example. Figure 14 (b) is a cross-sectional view of the light-emitting device of the seventh variation. Figure 14 (c) is a cross-sectional view of the light-emitting device in the eighth modified example. Figure 14 (d) is a cross-sectional view of the light-emitting device of the ninth modified example. Figure 14 (e) is Figure 14 An enlarged view of the portion indicated by arrow D in (a). Figure 14 (f) is Figure 14 An enlarged view of the portion indicated by arrow E in (b). Figure 14 (g) is Figure 14 An enlarged view of the portion indicated by arrow F in (c). Figure 14 (a)~ Figure 14 (d) is along Figure 2 The cross-sectional view corresponding to the cross-sectional view of line A-A' shown.

[0126] The light-emitting device 8a differs from the light-emitting device 7b in that it has white resin 60. The structure and function of the constituent elements of the light-emitting device 8a, excluding the white resin 60, are the same as those of the constituent elements of the light-emitting device 7b, which is marked with the same symbols, so detailed descriptions are omitted here.

[0127] The white resin 60, like the reflective material 42, is formed of silicone resin containing white particles such as titanium dioxide and is disposed between the first light-emitting element 21 and the second light-emitting element 22. By disposing the white resin 60 between the first light-emitting element 21 and the second light-emitting element 22, the light-emitting device 8a can suppress the amount of light absorbed by the substrate 40 and improve the light-emitting efficiency. Alternatively, the reflective material 50 and the diffusion layer 53 can be omitted.

[0128] The difference between light-emitting device 8b and light-emitting device 8a is that it has a first light-emitting element 61 and a second light-emitting element 62 instead of the first light-emitting element 21 and the second light-emitting element 22. The structure and function of the constituent elements of light-emitting device 8b other than the first light-emitting element 61 and the second light-emitting element 62 are the same as the structure and function of the constituent elements of light-emitting device 8a, which are marked with the same symbols, so detailed descriptions are omitted here.

[0129] The difference between the first light-emitting element 61 and the second light-emitting element 62 and the first light-emitting element 21 and the second light-emitting element 22 is that the sides of the fluorescent resin in the first light-emitting element 61 and the second light-emitting element 62 are not upright but open outwards and upwards. In the light-emitting device 8a, by distributing white resin 60 between the first light-emitting element 61 and the second light-emitting element 62, the white resin 60 functions as a reflective material, which can further improve the luminous efficiency. Alternatively, the reflective material 50 and the diffusion layer 53 can be omitted.

[0130] The light-emitting device 8c differs from the light-emitting device 8a in that it uses white resin 60a instead of white resin 60. Additionally, the light-emitting device 8c uses transparent resin 60b, which is different from the light-emitting device 8a. Except for the white resin 60a and transparent resin 60b, the structure and function of the constituent elements of the light-emitting device 8c are the same as those of the light-emitting device 8a, which is marked with the same symbols; therefore, detailed descriptions are omitted here.

[0131] The difference between white resin 60a and white resin 60 is that a recess is formed between the first light-emitting element 21 and the second light-emitting element 22 for disposing of transparent resin 60b. Except for the formation of the recess, the structure and function of white resin 60a are the same as those of white resin 60, therefore detailed descriptions are omitted here. Transparent resin 60b is disposed between the first light-emitting element 21, the second light-emitting element 22, and the white frame 63. Transparent resin 60b is disposed along the side of the phosphor resin 25 of the first light-emitting element 21 and the second light-emitting element 22, opening outwards with the side facing upwards.

[0132] The light-emitting device 8d differs from the light-emitting device 8a in that it has a white frame 63 and a frame material 64 instead of the reflective material 50, the light-guiding layer 51, the diffusion layer 52, and the white resin 60. The structure and function of the constituent elements of the light-emitting device 8d, except for the white frame 63 and the frame material 64, are the same as those of the constituent elements of the light-emitting device 8a, which are labeled with the same symbols, so detailed descriptions are omitted here.

[0133] The white frame 63 is formed of a white resin material with higher rigidity than the white resin 60, and has a plurality of insertion holes for the insertion of the first light-emitting element 21 and the second light-emitting element 22. The frame material 64 includes a light guide layer 65 and a diffusion layer 66 adhered to the light guide layer 65. The light guide layer 65 is a transparent sheet that allows light emitted from the first light-emitting element 21 and the second light-emitting element 22 to pass through, and the diffusion layer 66 is a diffusion sheet that diffuses the light emitted from the first light-emitting element 21 and the second light-emitting element 22.

[0134] Figure 15 This is a cross-sectional view of the light-emitting device of the tenth modification. The light-emitting device 6a differs from light-emitting device 6 in that it has a light-guiding layer 47 instead of a light-guiding layer 43. The structure and function of the constituent elements of light-emitting device 6a, except for the light-guiding layer 47, are the same as those of the constituent elements of light-emitting device 6, which are labeled with the same symbols; therefore, detailed descriptions are omitted here. The light-guiding layer 47 differs from light-guiding layer 43 in that it has a phosphor layer 48 instead of a phosphor layer 45. The phosphor layer 48 is offset around the first light-emitting element 41. The phosphor layer 48 is formed by phosphor deposition, coating, electrophoresis, etc.

[0135] The thickness T between the surface of the first light-emitting element 41 and the surface of the light guide layer 47 is T1 or higher, calculated by Equation (1) based on the distance between adjacent first light-emitting elements 41. Alternatively, it is T2 or lower, calculated by Equation (2) based on the distance between two first light-emitting elements 41 arranged with one first light-emitting element 41 separated from the surface of the first light-emitting element 41 and the surface of the light guide layer 23.

[0136] Furthermore, the thickness T between the surface of the first light-emitting element 41 and the surface of the light guide layer 47 is T3 or more, calculated by equation (3) based on the distance between adjacent first light-emitting elements 41. In addition, it is T4 or less, calculated by equation (4) based on the distance between two first light-emitting elements 41 arranged with one first light-emitting element 41 between the surface of the first light-emitting element 41 and the surface of the light guide layer 23.

[0137] The light-emitting device 6a emits light emitted from the first light-emitting element 41 and light emitted from the phosphor contained in the phosphor layer 48 biased around the first light-emitting element 41 through the transparent layer 46, thereby emitting light with high color mixing.

[0138] Figure 16 This is a perspective view of the light-emitting device of the eleventh variation.

[0139] The light-emitting device 9 includes a substrate 70, a first light-emitting element 71, a light-guiding layer 72, and a connector 73. The substrate 70 is, for example, a glass epoxy resin substrate, and has a wiring pattern forming the connection between the first light-emitting element 71 and the connector 73. The first light-emitting element 71 is an SMD type light-emitting element, arranged in a 4×4 matrix at the center of the surface of the substrate 70. The light-guiding layer 72 is formed of silicone resin and is configured to cover the first light-emitting element 71.

[0140] The thickness of the light guide layer 72, that is, the thickness between the surface of the LED chip of the first light-emitting element 71 and the surface of the light guide layer 72, is T1 or more, calculated by formula (1) based on the distance between adjacent first light-emitting elements 71. In addition, it is T2 or less, calculated by formula (2) based on the distance between two first light-emitting elements 71 arranged with one first light-emitting element 71 between the surface of the LED chip of the first light-emitting element 71 and the surface of the light guide layer 72.

[0141] The light-emitting device 9 uses an SMD-type light-emitting element, which can achieve the same optical characteristics as a COB-type light-emitting device. In addition, the light-emitting device 9 has multiple electronic components mounted on the substrate 70, and also has a control circuit that controls the light emission of multiple first light-emitting elements, etc., thereby enabling the light-emitting device capable of various controls such as dimming to be mounted on a single substrate.

[0142] Figure 17 This is a perspective view of the light-emitting device in the twelfth variation.

[0143] The light-emitting device 9a includes a substrate 80, a first light-emitting element 81, a second light-emitting element 82, a frame material 83, and electronic components 84. The substrate 80, like the substrate 70, is a glass epoxy board, and has a pair of electrodes 80a disposed thereon, with wiring patterns forming between the first light-emitting element 81, the second light-emitting element 82, and the electronic components 84 and the pair of electrodes 80a. The first light-emitting element 81 and the second light-emitting element 82, like the first light-emitting element 21 and the second light-emitting element 22, are CSP-type light-emitting elements, emitting cool-colored and warm-colored light. The frame material 83 has a reflective portion 85 and a light-guiding portion 86 integrally formed with the reflective portion 85 as a light-guiding layer. The reflective portion 85 is a frame material made of synthetic resin that reflects light emitted from the first light-emitting element 81 and the second light-emitting element 82, and is disposed to surround the first light-emitting element 81 and the second light-emitting element 82. The light-guiding portion 86 is a frame material made of synthetic resin that transmits light emitted from the first light-emitting element 81 and the second light-emitting element 82, and is disposed to cover the first light-emitting element 81 and the second light-emitting element 82. Electronic components 84 include resistors, capacitors, MOSFETs, and semiconductor devices, enabling various controls such as flicker suppression and dimming.

[0144] The light-emitting device disclosed herein, by disposing a light guide layer of a predetermined thickness between the light-emitting element and the diffuser layer, can suppress the reduction in light beam and emit light with high color mixing properties. By including the light guide layer, the light-emitting device of this disclosure can suppress the variation in the brightness of the emitted light by approximately 20-30% compared to a device without a light guide layer. Furthermore, the light-emitting device of this disclosure, in addition to the light guide layer, also includes a diffuser layer, thereby suppressing the variation in the brightness of the emitted light by approximately 40-60% compared to a device without a light guide layer.

[0145] Furthermore, the light-emitting device of this disclosure, by having a light-guiding layer, can suppress the variation in the chromaticity of the emitted light by about 3 to 30% compared to the case without a light-guiding layer. In addition, the light-emitting device of this disclosure, besides having a light-guiding layer, also has a diffusion layer, which, compared to the case without a light-guiding layer, can suppress the variation in the chromaticity of the emitted light by about 45 to 75%.

[0146] Furthermore, in the described light-emitting device, the light guide layer is formed of silicone resin, but in the light-emitting device of this disclosure, the light guide layer may also be formed of synthetic resins such as epoxy resin, polymethyl methacrylate resin, polycarbonate resin, and polystyrene resin. Additionally, in the described light-emitting device, the light guide layer is formed of silicone resin as a single resin, but it may also be formed by layering multiple synthetic resins with different refractive indices. When the light guide layer is formed by layering multiple synthetic resins with different refractive indices, the thickness of the light guide layer is determined according to formulas (1) to (4) for each resin layer.

[0147] Furthermore, in the light-emitting device disclosed herein, the reflective layer may also be formed from multiple reflective layers arranged overlapping with the substrate. When the reflective layer is formed from multiple reflective layers arranged overlapping with the substrate, the center portion of the uppermost reflective layer may also be disposed outside the center portions of the other reflective layers. By disposing the center portion of the uppermost reflective layer outside the center portions of the other reflective layers, when the resin of the light guide layer before curing is filled into the inner side of the reflective material, the resin of the light guide layer before curing will not climb to the uppermost reflective layer, thus forming a flat light guide layer.

[0148] The light-emitting element used in the descriptions so far is an element such as an LED chip 24 that emits blue light, covered with fluorescent resin or the like. In a light-emitting device equipped with a color filter, when a white LED is placed in a region of the color filter divided by one color and another white LED is placed in a region divided by another color, the combination of a region and the white LED placed in that region constitutes a light-emitting element. The entire set of color filters and white LEDs corresponds to a light-emitting element. The light-emitting device that uses a color filter as a light-emitting element follows the relationship described with reference to formulas (1) to (4). Similarly, the relationship described with reference to formulas (1) to (4) also applies to micro-LEDs or organic ELs with fine light-emitting parts arranged in a specific pattern.

[0149] Furthermore, when the light emission of each light-emitting element can be independently controlled, the light-emitting device of this disclosure can also be used as a display. However, the light-emitting device of this disclosure can improve the brightness uniformity and color mixing of the emitted light without reducing the resolution.

Claims

1. A light-emitting device, characterized in that, have: substrate; A plurality of first light-emitting elements are mounted on the substrate and have first LED chips that emit light having a first wavelength; and A light guide layer, configured to cover the plurality of first light-emitting elements, guides the light emitted from the plurality of first light-emitting elements. The thickness T between the surface of the first LED chip and the surface of the light guide layer is thicker than the thickness T1 expressed as T1=LG1 / (2tanθc). Wherein, LG1 is the spacing between the first LED chips, and θc is the critical angle at which light is emitted from the light guide layer into the air. The thickness T between the surface of the first LED chip and the surface of the light guide layer is thinner than the thickness T2 expressed as T2=LG2 / (2tanθc). LG2 is the spacing distance between two first LED chips that are separated by one of the first light-emitting elements.

2. The light-emitting device according to claim 1, characterized in that, It also has a plurality of second light-emitting elements mounted on the substrate in an alternating manner with each of the plurality of first light-emitting elements, and has a second LED chip that emits light having a second wavelength different from the first wavelength.

3. The light-emitting device according to claim 2, characterized in that, It also has a white resin disposed between the plurality of first light-emitting elements and the plurality of second light-emitting elements.

4. The light-emitting device according to claim 3, characterized in that, Each of the plurality of first light-emitting elements further includes a first phosphor resin covering the first LED chip. Each of the plurality of second light-emitting elements further includes a second phosphor resin covering the second LED chip. The sides of the first phosphor resin and the second phosphor resin are configured to open outwards and upwards.

5. The light-emitting device according to claim 4, characterized in that, It also includes a transparent resin, which is configured such that its sides face upward and open outward. Each of the plurality of first light-emitting elements further includes a first phosphor resin covering the first LED chip. Each of the plurality of second light-emitting elements further includes a second phosphor resin covering the second LED chip. It is disposed along the side of the first phosphor resin and the second phosphor resin.

6. The light-emitting device according to claim 1, characterized in that, It also has: Multiple second light-emitting elements, each having a second LED chip, emit light with a second wavelength different from the first wavelength; and Multiple third light-emitting elements, each having a third LED chip, emit light with a third wavelength different from the first and second wavelengths. The spacing between the plurality of first LED chips is greater than the spacing between the second LED chip and the third LED chip.

7. The light-emitting device according to claim 1, characterized in that, It also includes a reflective material disposed on the substrate in a manner that surrounds the plurality of first light-emitting elements, reflecting light emitted from the first light-emitting elements. The light guide layer includes a phosphor layer and a transparent layer. The phosphor layer contains a phosphor that absorbs light emitted from the plurality of first light-emitting elements and emits light having a second wavelength different from the first wavelength. The transparent layer is disposed above the phosphor layer and does not contain the phosphor. The distance LB1 between the first LED chip, which is positioned adjacent to the reflective material and separated by another first light-emitting element, and the reflective material is shorter than Ttanθc.

8. The light-emitting device according to claim 7, characterized in that, The distance LB2 between the first LED chip, which is arranged adjacent to the reflective material with another first light-emitting element in between, and the reflective material is longer than Ttanθc.

9. The light-emitting device according to any one of claims 1 to 7, characterized in that, It also has a diffusion layer configured to cover the light guide layer, thereby diffusing the light guided in the light guide layer.

10. The light-emitting device according to claim 2 or 3, characterized in that, The light guide layer and the diffusion layer are integrated into a frame material. The diffusion layer is configured to cover the light guide layer and diffuse the light guided in the light guide layer.

11. The light-emitting device according to any one of claims 1 to 8, characterized in that, The plurality of first light-emitting elements are surface-mount light-emitting elements.

12. The light-emitting device according to any one of claims 1 to 8, characterized in that, It also has a control circuit, which has multiple electronic components mounted on the substrate to control the light emission of the multiple first light-emitting elements.

Images