Light emitting device

Abstract

The present application provides a light emitting device which can make a cut-off line clear using a simple and small optical system structure when used as a light source for a headlamp. The light emitting device has a substrate, a light emitting element provided on the substrate, a plate-shaped light-transmissive member provided so that a lower surface thereof opposes an upper surface of the light emitting element as a light emitting surface, and a cover member covering a side surface of the light emitting element and a side surface of the light-transmissive member. The upper surface of the light emitting element is rectangular in shape having a first side and a second side opposing each other and a third side and a fourth side opposing each other, and the upper surface of the light-transmissive member is rectangular in shape having a fifth side and a sixth side opposing each other and a seventh side and an eighth side opposing each other. The light-transmissive member is provided on the light emitting element so that the fifth side is located outward of the first side and the sixth side is located inward of the second side when viewed from above.

Description

[0001] This application is a divisional application of the invention patent application filed on September 27, 2018, with application number 201811130142.4 and title "Light-emitting device". Technical Field

[0002] This invention relates to light-emitting devices, and more particularly to light-emitting devices for headlights. Background Technology

[0003] Semiconductor light-emitting elements such as light-emitting diodes (LEDs) and laser diodes are used as various light sources, and in recent years, they have been widely used as light sources for automotive headlights. In addition to high brightness, the light source for automotive headlights requires a specific light distribution, such as a Lambertian distribution. As a light-emitting device suitable for use in such headlights, Patent Document 1 discloses a light-emitting device having a semiconductor light-emitting element disposed on a substrate surface, a reflective frame surrounding the semiconductor light-emitting element on the substrate, and a transparent phosphor layer covering the upper surface and sides of the semiconductor light-emitting element. Furthermore, according to this light-emitting device, light can be emitted in one direction from the opening of the reflective frame by reflecting light from the inner peripheral wall surface of the frame, thereby increasing the illuminance on the front side of the vehicle, making it suitable for use as a headlight.

[0004] Furthermore, when the headlights are in low beam, they need to illuminate the road surface above the cutoff line without dazzling oncoming vehicles. The boundary line of the light above the cutoff line in low beam is called the cutoff line 210. If this cutoff line 210 is unclear, meaning the low beam only illuminates above the cutoff line 210, it is not preferable from a safety perspective. Figure 14 Therefore, the headlights of the vehicle are designed with an optical system that ensures a clear cutoff line 210 in low beam conditions. Even for the light-emitting device used as the headlight light source, it is required to design an optical system with a clear cutoff line 210. Specifically, for the light-emitting device, for example, it is required that the boundary between the light-emitting surface and the reflective frame (covering component) surrounding the light-emitting surface be clear, i.e., as... Figure 13 As shown, the brightness changes abruptly on the outer and inner sides of this boundary. To clearly define the boundary between the luminescent surface and the covering component surrounding it, as... Figure 15 As illustrated schematically, a more effective approach is to increase the size of the wavelength conversion component 207 disposed on the light-emitting element 201, to arrange the wavelength conversion component 207 on the light-emitting element 201 such that the outer periphery of the wavelength conversion component 207 is further outward than the outer periphery of the light-emitting surface of the light-emitting element 201, and to provide a covering component on the light-emitting element 201 in a manner that surrounds the wavelength conversion component 207.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-76455

[0006] However, if the phosphor plate (wavelength conversion component) is positioned on the light-emitting element with its outer periphery further out than the outer periphery of the light-emitting surface, the light-emitting surface of the light-emitting device will inevitably become larger. If the light-emitting surface of the light-emitting device becomes larger, there is a technical problem of increasing the structural size of the headlight's optical system. Summary of the Invention

[0007] Therefore, the object of the present invention is to provide a light-emitting device that, when used as a light source for a headlight, can make the cut-off line between light and dark clear using a simple and small optical system structure.

[0008] To achieve the above objectives, a light-emitting device according to an embodiment of the present invention is characterized by having:

[0009] substrate;

[0010] A light-emitting element is disposed on the substrate;

[0011] A plate-shaped light-transmitting component is arranged such that its lower surface is opposite to the upper surface of the light-emitting element, which serves as the light-emitting surface;

[0012] A covering component that covers the side of the light-emitting element and the side of the light-transmitting component;

[0013] The upper surface of the light-emitting element is a rectangular shape with a first and a second side facing each other, and a third and a fourth side facing each other.

[0014] The upper surface of the light-transmitting component is a rectangular shape with a fifth and a sixth side facing each other, and a seventh and a eighth side facing each other.

[0015] The light-transmitting component is disposed on the light-emitting element such that, when viewed from above, the fifth side is located outside the first side and the sixth side is located inside the second side.

[0016] When the light-emitting device of one embodiment of the present invention is used as a light source for a headlight, it can make the cut-off line between light and dark clear by utilizing the structure of a simple and small optical system. Attached Figure Description

[0017] Figure 1 This is a perspective view of a light-emitting device according to an embodiment of the present invention.

[0018] Figure 2 This is a top view of the light-emitting device according to the embodiment.

[0019] Figure 3 yes Figure 2 A sectional view at line A-A.

[0020] Figure 4 yes Figure 2A sectional view at line B-B.

[0021] Figure 5 It is a graph showing the relative brightness on the light-emitting surface of the light-emitting device in the embodiment.

[0022] Figure 6 This is a top view of the light-emitting device of Modification 1 of the present invention.

[0023] Figure 7 This is a top view of the light-emitting device of Modification 2 of the present invention.

[0024] Figure 8 yes Figure 7 A cross-sectional view at line C-C.

[0025] Figure 9 This is a top view of the light-emitting device of Modification 3 of the present invention.

[0026] Figure 10 This is a top view of the light-emitting device of Modification 4 of the present invention.

[0027] Figure 11 This is a top view of the light-emitting device of Modification 5 of the present invention.

[0028] Figure 12 This is a top view of the light-emitting device of a modified example 5 of the present invention.

[0029] Figure 13 It is a graph representing the relative brightness of the light-emitting surface of a conventional light-emitting device.

[0030] Figure 14 It is a graph representing the illumination characteristics of the low beam of the headlight.

[0031] Figure 15 This is a top view of a previous example of a light-emitting device.

[0032] Explanation of reference numerals in the attached figures

[0033] 1 Light-emitting element

[0034] 1a First side 1a

[0035] 1b second side 1b

[0036] 1c third side 1c

[0037] 1d fourth side 1d5 cover component

[0038] 7. Light-transmitting components

[0039] 7a Fifth side 7a

[0040] 7b Sixth side 7b

[0041] 7b1 Sixth inner side

[0042] 7b2 Sixth outer side

[0043] 7c Seventh side 7c

[0044] 7d eighth side 7d

[0045] 7s top surface

[0046] 7s1 first upper surface

[0047] 7s2 second upper surface

[0048] 8. Fluorescent cells

[0049] 10 substrate

[0050] 20 Conductive joint components

[0051] 40 Light guide components

[0052] 100 light-emitting devices Detailed Implementation

[0053] In order to provide a light-emitting device that can clearly achieve a cut-off line between light and dark using a simple and compact optical system when used as a headlight light source, the inventors conducted in-depth research. The results showed that in a light-emitting device with a rectangular light-emitting surface, as long as the brightness of the outer and inner sides of one side of the boundary between the light-emitting surface and the covering member surrounding the outer periphery of the light-emitting surface changes abruptly, the light-emitting device can achieve a clear cut-off line between light and dark using a simple optical system structure when used as a headlight light source. That is, in a rectangular light-emitting surface, as long as a boundary with a sharp brightness change is provided for one side, even if the brightness at the boundaries of other sides changes gradually, the cut-off line between light and dark can still be clear when used as a headlight light source. The light-emitting device of this embodiment was completed based on the above ideas.

[0054] Specifically, in the light-emitting device of this embodiment, in a structure in which a light-transmitting member is placed on the light-emitting surface of the light-emitting element and a covering member is provided around the light-transmitting member,

[0055] (1) The light-transmitting component is placed on the light-emitting surface of the light-emitting element with one edge of the light-transmitting component located outside one edge of the light-emitting surface of the light-emitting element, such that at the boundary between the aforementioned edge of the light-transmitting component and the covering component, the brightness of the outer and inner sides changes drastically.

[0056] (2) For any one or more of the other three sides besides the one side, the light-transmitting component is positioned inside the light-emitting surface of the light-emitting element by placing one side of the light-transmitting component inside the light-emitting surface of the light-emitting element, thereby reducing the area of ​​the light-emitting surface accordingly.

[0057] Note that on one side of the light-transmitting component (one side of the light-emitting surface of the light-emitting device) located inside the light-emitting surface of the light-emitting element, the brightness change between the outer and inner sides of this side is gradual, but it has little impact on the clarity of the light-dark cutoff line.

[0058] The light-emitting device of the embodiment will be described in detail below.

[0059] Hereinafter, the light-emitting device according to an embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a perspective view of the light-emitting device according to an embodiment of the present invention. Figure 2 This is a top view of the light-emitting device according to the embodiment. Additionally, Figure 3 yes Figure 2 A sectional view at line A-A. Figure 4 yes Figure 2 A sectional view at line B-B.

[0060] The light-emitting device 100 of the embodiment includes:

[0061] (a) Substrate 10;

[0062] (b) A light-emitting element 1, which is disposed on a substrate 10;

[0063] (c) A plate-shaped light-transmitting component 7, wherein its lower surface is disposed opposite to the upper surface of the light-emitting element 1, which serves as the light-emitting surface;

[0064] (d) Covering component 5, which covers the side of the light-emitting element 1 and the side of the light-transmitting component 7.

[0065] like Figure 3 and Figure 4 As shown, the light-emitting element 1 is mounted on the substrate 10 in a flip-chip configuration, for example, via a conductive bonding member 20. Note that this is a simplified representation. Figure 3 and Figure 4 The light-emitting element 1 has, for example, a p-side electrode and an n-side electrode on the same side. The p-side electrode and the n-side electrode are respectively connected to a first electrode 11 or a second electrode 12 disposed on the substrate 10 via a conductive bonding member 20. A light-transmitting member 7, as detailed later, is bonded to the light-emitting surface of the light-emitting element 1 via a light-guiding member 40. Furthermore, the light-transmitting member 7 includes a phosphor 8, which emits light when excited by light from the light-emitting element 1, and the wavelength of this light is longer than the wavelength of the light emitted by the light-emitting element 1.

[0066] The cover member 5 is, for example, a reflective member containing white pigment in a base material made of resin or the like, covering the side surfaces of the light-emitting element 1, the light-guiding member 40, and the light-transmitting member 7 on the substrate 10. The cover member 5 surrounds the side surfaces of the light-emitting element 1 and the light-transmitting member 7 in the entire circumference. Furthermore, the upper surface 7s of the light-transmitting member 7 (i.e., the light-emitting surface of the light-emitting device 100) and the upper surface of the cover member 5 are substantially the same surface. In the light-emitting device 100 configured as described above, since the light emitted from the light-emitting element 1 and the light-transmitting member 7 to the side is reflected by the cover member 5 and emitted from above, the efficiency of extracting light from above can be improved.

[0067] Here, in particular, in the light-emitting device 100, by Figure 2 and Figure 4 It is understood that the light-transmitting component 7 is offset and positioned on the light-emitting element 1. If the light-emitting device 100 configured in this way is used as the light source assembly of a headlight, it is possible to produce a headlight with a clear cut-off line in the light distribution pattern through a simple and small optical system.

[0068] <Configuration of light-emitting element 1 and light-transmitting component 7>

[0069] like Figure 2 As shown, the upper surface of the light-emitting element 1 is a rectangular shape with a first side 1a and a second side 1b facing each other, and a third side 1c and a fourth side 1d facing each other. Furthermore, the upper surface 7s of the light-transmitting component 7 is a rectangular shape with a fifth side 7a and a sixth side 7b facing each other, and a seventh side 7c and an eighth side 7d facing each other.

[0070] And, as Figure 2 As shown, the light-transmitting component 7 is positioned on the light-emitting element 1 such that, when viewed from above, the fifth side 7a is located outside the first side 1a and the sixth side 7b is located inside the second side 1b. Here, as... Figure 2 As shown in the figures, the light-emitting device of the embodiment includes a plurality of light-emitting elements 1, such as... Figure 2 As shown, the light-transmitting component 7 is disposed on the two light-emitting elements 1 with the fifth side 7a located outside the first side 1a of the two light-emitting elements 1 and the sixth side 7b located inside the second side 1b of the two light-emitting elements 1.

[0071] In the light-emitting device 100 of this embodiment, when it includes a plurality of light-emitting elements 1 each having a first side 1a to a fourth side 1d, the plurality of light-emitting elements 1 preferably have their first sides 1a respectively located on the same straight line (first straight line). Furthermore, the plurality of light-emitting elements 1 are more preferably arranged on the substrate 10 such that their first sides 1a are respectively located on the first straight line and their second sides 1b are respectively located on a second straight line parallel to the first straight line.

[0072] Furthermore, the upper surface 7s of the light-transmitting member 7 is preferably a substantially flat surface that is substantially parallel to the lower surface of the light-transmitting member 7. In addition, among the side surfaces of the light-transmitting member 7 that are connected to the upper surface 7s, the side surface that is connected to the upper surface 7s via the fifth side 7a is preferably a surface that is connected to the lower surface and is substantially perpendicular to the upper surface 7s.

[0073] In the embodiment described above, the light-emitting device 100 is configured such that, when viewed from above, the fifth side 7a of the light-transmitting member 7 is located outside the first side 1a of the light-emitting element 1. Therefore, the brightness of the outer and inner sides can change drastically, with the boundary between the light-emitting surface of the corresponding fifth side 7a of the light-transmitting member 7 and the covering member 5 as the boundary. Figure 5 (The rising portion of relative brightness on the left side of the graph shown). Therefore, when the light-emitting device 100 is used as the light source of a headlight, it is possible to manufacture a headlight that makes the cut-off line between light and dark clear using an optical system with a simple structure.

[0074] Furthermore, since the light-emitting device 100 of the embodiment places the light-transmitting member 7 on the light-emitting element 1 such that the sixth side 7b of the light-transmitting member 7 is located inside the second side 1b of the light-emitting element 1 when viewed from above, the width of the upper surface 7s of the light-transmitting member 7, or in other words, the width of the light-emitting surface of the light-emitting device 100, can be reduced. That is, the area of ​​the light-emitting surface can be reduced. As a result, when the light-emitting device 100 is used as a light source for a headlight, the optical system can be made smaller. Note that if the light-transmitting member 7 is placed on the light-emitting element 1 such that the sixth side 7b of the light-transmitting member 7 is located inside the second side 1b of the light-emitting element 1, the brightness of the light-emitting surface of the corresponding sixth side 7b of the light-transmitting member 7 changes smoothly between the outer and inner sides of the boundary of the covering member 5. Figure 5 (The rising portion of relative brightness on the right side of the graph shown). However, since the light-emitting device 100 of the embodiment arranges the light-transmitting member 7 such that the fifth side 7a of the light-transmitting member 7 is located outside the first side 1a of the light-emitting element 1 when viewed from above, the sixth side 7b of the light-transmitting member 7 being located inside the second side 1b of the light-emitting element 1 has little impact on the clarity of the light-dark cutoff line. Here, Figure 5 The graph of relative brightness shown illustrates Figure 2 The relative brightness at the cross-section of line B-B shown.

[0075] As explained above, according to Embodiment 1, by using the light-emitting device 100 as the light source of the headlight, a headlight with a clear cut-off line can be constructed using a simple and small optical system.

[0076] In the light-emitting device of the above embodiments, the light-transmitting member 7 is arranged such that the seventh side 7c and the eighth side 7d of the light-transmitting member 7 are located outside the third side 1c and the fourth side 1d of the light-emitting element 1, respectively. As a result, the brightness difference between the outer and inner sides can be suppressed by using the seventh side 7c and the eighth side 7d as the boundary. When the light-emitting device 100 is used as a light source for a headlight, a headlight with a clear cut-off line can be produced using an optical system with a simpler structure.

[0077] In the light-emitting device of the embodiment, the light-transmitting member 7 may be disposed on the light-emitting element 1 such that the seventh side 7c and the eighth side 7d are located inside the third side 1c and the fourth side 1d, respectively. In this way, the area of ​​the light-emitting surface of the light-emitting device 100 can be reduced, and therefore the optical system can be made smaller when the light-emitting device 100 is used as a light source for a headlight.

[0078] In the light-emitting device of the embodiment, the light-transmitting component 7 may also be provided on the light-emitting element in such a way that the seventh side 7c is located inside the third side 1c and the eighth side 7d is located outside the fourth side 1d.

[0079] In the light-emitting device of the above embodiments, a light-transmitting component 7 is configured to cover a plurality of light-emitting elements 1.

[0080] However, the light-emitting device of the embodiment is not limited to this, and it may also be a structure in which a light-transmitting component 7 covers a light-emitting element 1. In addition, as shown in the modified examples described later, multiple light-transmitting components 7 may be provided to cover one or more light-emitting elements 1 respectively.

[0081] In the light-emitting device of the above embodiments, the light-transmitting component 7 is disposed on the light-emitting element 1 such that when viewed from above, the fifth side 7a is located outside the first side 1a and the sixth side 7b is located inside the second side 1b.

[0082] However, the light-emitting device of the embodiment is not limited to this. The light-transmitting component 7 may also be provided on the light-emitting element 1 in such a way that when viewed from above, the fifth side 7a overlaps with the first side 1a and the sixth side 7b is located inside the second side 1b.

[0083] The light-emitting device in the above embodiments is composed of a light-transmitting component 7 containing a phosphor 8.

[0084] However, the light-emitting device of the embodiment is not limited to this, and may also be composed of a light-transmitting component 7 that does not contain a phosphor.

[0085] Variation Example 1

[0086] Figure 6 This is a top view of the light-emitting device of Modification 1 of the present invention.

[0087] The light-emitting device of this variant 1 is constructed using four light elements 1, which is consistent with... Figure 2 The light-emitting device shown is different from that in the embodiment, but the others are the same as the light-emitting device in the implementation.

[0088] The light-emitting device of Modified Example 1 constructed in the above manner has the same effect as the light-emitting device of the Embodiment 1, and is similar to... Figure 2 Compared to the light-emitting devices shown, the brightness can be further improved.

[0089] Variation Example 2

[0090] Figure 7 This is a top view of the light-emitting device of Modification 2 of the present invention. Additionally, Figure 8 This is a cross-sectional view of the light-emitting device in variation example 2. Figure 7 The cross-section at the C-C line.

[0091] The light-emitting device of Modification 2 differs from that of Modification 1 in the shape of the light-transmitting member 7, but is otherwise identical in configuration. In the light-emitting device of Modification 2, the light-transmitting member 7 includes a second upper surface lower than the first upper surface outside the upper surface 7s (hereinafter referred to as the "first upper surface") of the light-transmitting member 7 of Modification 2, and this second upper surface is covered by the covering member 5. Hereinafter, aspects that differ from the embodiment and Modification 1 will be specifically described.

[0092] In the light-emitting device of Modification 2, the light-transmitting component 7 has a lower surface that engages with the light-emitting element 1 and an upper surface opposite to the lower surface. The lower surface of the light-transmitting component 7 is composed of a substantially flat lower surface, while its upper surface has at least two upper surfaces, a first upper surface 7s1 and a second upper surface 7s2. There is a step difference between the first upper surface 7s1 and the second upper surface 7s2. Specifically, the thickness of the light-transmitting component 7 below the second upper surface 7s2 is thinner than the thickness of the light-transmitting component 7 below the first upper surface 7s1.

[0093] In the light-emitting device of Modified Example 2, the first upper surface 7s1 of the light-transmitting member 7 has a fifth side 7a and a sixth inner side 7b1 opposite to the fifth side 7a. The second upper surface 7s2 of the light-transmitting member 7 has a sixth outer side 7b2 located outside the sixth inner side 7b1.

[0094] Furthermore, in the light-emitting device of Modified Example 2, such as Figure 7 and Figure 8As shown, the light-transmitting component 7 is disposed on the light-emitting element 1 such that when viewed from above, (a) the fifth side 7a is located outside the first side 1a of the light-emitting element 1, (b) the sixth inner side 7b1 is located inside the second side 1b of the light-emitting element 1, and (c) the sixth outer side 7b2 is located outside the second side 1b of the light-emitting element 1.

[0095] Note that, at this time, the first upper surface 7s1 of the light-transmitting component 7 is preferably a substantially flat surface that is substantially parallel to the lower surface. Among the side surfaces of the light-transmitting component 7 connected to the first upper surface 7s1, the side surface connected to the first upper surface 7s1 at least via the fifth side 7a is preferably a surface connected to the lower surface and substantially perpendicular to the first upper surface 7s1. In addition, the second upper surface 7s2 can be either a surface that is substantially parallel to the lower surface or an inclined surface that is inclined relative to the lower surface.

[0096] In the light-emitting device of Modified Example 2, the covering member 5 is arranged such that the first upper surface 7s1 is exposed and the second upper surface 7s2 is covered. Thus, the first upper surface 7s1 of the light-transmitting member 7 becomes the light-emitting surface of the light-emitting device.

[0097] Because the light-emitting device of Modified Example 2, constructed as described above, has its fifth side 7a of the light-transmitting member 7 positioned outside the first side 1a of the light-emitting element 1 when viewed from above, the brightness of the light-emitting surface corresponding to the fifth side 7a of the light-transmitting member 7 can change drastically between the outer and inner sides of the boundary between the light-emitting surface and the covering member 5. Therefore, when the light-emitting device of Modified Example 2 is used as a headlight source, a headlight with a clear cut-off line can be manufactured using a simple optical system.

[0098] Furthermore, since the light-emitting device of Modified Example 2 is positioned such that the sixth inner side 7b1 of the light-transmitting member 7 is located inside the second side 1b of the light-emitting element 1 when viewed from above, the width of the first upper surface 7s1 of the light-transmitting member 7, or in other words, the width of the light-emitting surface of the light-emitting device, can be reduced, thereby reducing the area of ​​the light-emitting surface. Therefore, when the light-emitting device 100 is used as a headlight light source, the optical system can be made smaller.

[0099] Furthermore, in the light-emitting device of Modification 2, when the light-transmitting member 7 includes a phosphor, that is, when the desired emission color of the light-emitting device is obtained by using light containing light whose wavelength has been converted by the phosphor, since the lower surface of the light-transmitting member 7 covers the entire emission surface of the light-emitting element 1, it is possible to prevent the light emitted from the light-emitting element from leaking to the outside without passing through the light-transmitting member 7.

[0100] Variation Example 3

[0101] Figure 9This is a top view of the light-emitting device of Modification 3 of the present invention.

[0102] The light-emitting device of this variation 3 differs from the light-emitting device of the embodiment in that it has three light-emitting elements 1 and two light-transmitting components 7.

[0103] In the light-emitting device of Modification 3, a light-transmitting component 7 is provided above both light-emitting elements 1, and a light-transmitting component 7 is provided above one of the light-emitting elements 1. Specifically, as shown... Figure 9 As shown, one of the two light-transmitting components 7 is arranged across the two light-emitting elements 1 such that, when viewed from above, the fifth side 7a is located outside the first side 1a of the two light-emitting elements 1, and the sixth side 7b is located inside the second side 1b of the two light-emitting elements 1.

[0104] In addition, such as Figure 9 As shown, the other of the two light-transmitting components 7 is disposed on the light-emitting element 1 such that, when viewed from above, the fifth side 7a is located outside the first side 1a of the light-emitting element 1 and the sixth side 7b is located inside the second side 1b of the light-emitting element 1.

[0105] Thus, when the light-emitting device has multiple light-emitting elements 1, the number, spacing, and arrangement density of the light-transmitting component 7 and the light-emitting elements 1 can be combined to serve as a light source suitable for the desired light distribution pattern.

[0106] In the light-emitting device of Modification 3, two light-transmitting components 7 are arranged such that the seventh side 7c and the eighth side 7d of the light-transmitting component 7 are located outside the third side 1c and the fourth side 1d of the light-emitting element 1, respectively.

[0107] For the light-emitting device of Modified Example 3 constructed in the above manner, when the light-emitting device 100 is used as the light source of a headlight, a headlight with a clear cut-off line of light distribution pattern can be produced using an optical system with a simpler structure.

[0108] Furthermore, since the light-emitting device of Modified Example 3 can make the area of ​​the light-emitting surface smaller, the optical system can be made smaller when the light-emitting device of Modified Example 3 is used as the light source of a headlight.

[0109] Variation Example 4

[0110] Figure 10 This is a top view of the light-emitting device of Modification 4 of the present invention.

[0111] The light-emitting device of this modified example 4 is the same as that of the light-emitting device of modified example 3, except that two light-transmitting components 7 are provided in such a way that the seventh side 7c and the eighth side 7d of the light-transmitting component 7 are located inside the third side 1c and the fourth side 1d of the light-emitting element 1, respectively.

[0112] Since the light-emitting device of Modified Example 4 configured in the above manner can have a smaller light-emitting surface area compared with the light-emitting device of Modified Example 3, the optical system can be made smaller when the light-emitting device of Modified Example 4 is used as the light source of a headlight.

[0113] Variation Example 5

[0114] Figure 11 This is a top view of the light-emitting device of Modification 5 of the present invention.

[0115] The light-emitting device of this modified example 5 differs from that of the light-emitting device of modified example 4 in the shape of the two light-transmitting components 7, but the other configurations are the same as those of the light-emitting device of modified example 4.

[0116] Specifically, in the light-emitting device of Modified Example 5, the light-transmitting member 7 includes a second upper surface 7s2 that is lower than the first upper surface outside the upper surface (first upper surface 7s1) of the light-transmitting member 7 of Modified Example 4, and this second upper surface 7s2 is covered by the covering member 5. Furthermore, in the light-transmitting member 7 of Modified Example 5, the second upper surface 7s2 is arranged to surround three sides other than the fifth side 7a when viewed from above. Additionally, in the light-emitting device of Modified Example 5, each light-transmitting member 7 has a substantially flat lower surface that engages with the light-emitting element 1.

[0117] In the light-emitting device of Modified Example 5, the first upper surface 7s1 of the light-transmitting member 7 is configured such that, when viewed from above in a top view, it has the same positional relationship with the light-emitting element 1 as the upper surface 7s of the light-transmitting member 7 in the light-emitting device of Modified Example 4. Furthermore, the light-transmitting members 7 are respectively disposed on the light-emitting element 1 with their lower surfaces located on the outer periphery of the light-emitting element 1.

[0118] When the light-emitting device of Modified Example 5, constructed in the manner described above, is used as a light source for a headlight, it can produce a headlight with a clear cut-off line using an optical system with a simpler structure.

[0119] Furthermore, since the light-emitting device of Modified Example 5 allows for a smaller light-emitting surface area, it is possible to manufacture a light-emitting device for higher latitudes. Additionally, when used as a light source for a headlight, the optical system can be made more compact.

[0120] The light-emitting device of Modified Example 5 constructed in the above manner has the same effect as the light-emitting device of Modified Example 4. Furthermore, when the light-transmitting component 7 includes a phosphor, since the light-transmitting component 7 covers the entire light-emitting surface of the light-emitting element 1, the light emitted by the light-emitting element 1 can be efficiently irradiated onto the phosphor 8.

[0121] Variation Example 6

[0122] Figure 12 This is a top view of the light-emitting device of Modification 6 of the present invention.

[0123] In the light-emitting device of this modified example 6, the light-transmitting component 7 includes a second upper surface 7s2 located below the first upper surface 7s1 on the outer side of the first upper surface 7s1, and this second upper surface 7s2 is covered by the covering component 5. Furthermore, as... Figure 12 As shown, when viewed from above, the light-transmitting component 7 is positioned on top of the light-emitting element 1 such that its fifth side 7a is located outside the first side 1a of the light-emitting element 1, and its sixth inner side 7b1 and sixth outer side 7b2 are both located inside the second side 1b of the light-emitting element 1. Note that in the light-emitting device of Modified Example 6, the seventh side 7c and the eighth side 7d of the light-transmitting component 7 are both located outside the third side 1c and the fourth side 1d of the light-emitting element 1.

[0124] When the light-emitting device of Modified Example 6 constructed in the above manner is used as a light source for a headlight, it can produce a headlight with a clear cut-off line using an optical system with a simpler structure.

[0125] Furthermore, the light-emitting device of Modified Example 6 allows for a smaller light-emitting surface area, thus enabling a more compact optical system when used as a light source for a headlight.

[0126] The components and structure of the light-emitting device in this embodiment and its variations will be described below.

[0127] (Substrate 10)

[0128] The substrate 10 is a component for mounting a light-emitting element and has wiring for electrically connecting the electrodes of the light-emitting element to external electrodes. The main material of the substrate 10 is an insulating material, preferably a material through which light from the light-emitting element and external light are difficult to penetrate. Examples include ceramics such as alumina and aluminum nitride, phenolic resins, epoxy resins, polyimide resins, BT resins, and polyphthalamide resins. Note that when using resins, inorganic fillers such as glass fibers, silicon dioxide, titanium dioxide, and alumina may be mixed into the resin as needed. This improves mechanical strength, reduces the coefficient of thermal expansion, and increases light reflectivity. Alternatively, the substrate 10 may be a substrate formed by forming an insulating material on the surface of a metal component. The wiring is formed in predetermined clusters on the insulating material. The material for the wiring can be at least one selected from gold, silver, copper, and aluminum. The wiring can be formed by electroplating, vapor deposition, sputtering, etc.

[0129] (Light-emitting element 1)

[0130] As the light-emitting element 1, a light-emitting diode (LED) is preferably used. The light-emitting element can be selected from any wavelength. For example, as a blue or green light-emitting element, a ZnSe or nitride semiconductor (In) can be used. X Al Y Ga 1－X－Y Light-emitting elements can be made of GaAlAs, AlInGaP, etc., where N ≤ X, 0 ≤ Y, X + Y ≤ 1. Additionally, GaAlAs, AlInGaP, etc., can be used as red light-emitting elements. Furthermore, semiconductor light-emitting elements made of other materials can also be used. The composition, emission color, size, and number of the light-emitting elements used can be appropriately selected according to the purpose. In the case of a light-emitting device with a phosphor, nitride semiconductors (In...) capable of emitting short-wavelength light that can efficiently excite the phosphor can be appropriately listed. X Al Y Ga 1－X－Y N, 0≤X, 0≤Y, X+Y≤1). Various emission wavelengths can be selected by the material of the semiconductor layer and its crystallinity.

[0131] The light-emitting element in this embodiment has positive and negative electrodes on the same side, which are mounted on a substrate in a flip-chip manner via conductive bonding members. The upper surface of the light-emitting element, opposite to the lower surface where the electrodes are formed, serves as the main light-emitting surface. Because such a light-emitting element is connected to the substrate using conductive bonding members such as bumps and conductive paste, it can increase the contact area between the electrodes and the substrate and reduce the connection resistance compared to light-emitting elements connected by metal wires or the like.

[0132] The light-emitting element is, for example, a light-emitting element formed by stacking a nitride semiconductor layer on a transparent sapphire substrate for growth. The sapphire substrate becomes the upper surface side of the light-emitting element 1, constituting the main light-emitting surface. Note that the growth substrate can also be removed, for example, by grinding, LLO (Laser Lift Off), etc.

[0133] (Light-transmitting component 7)

[0134] The light-transmitting component 7 is a material that allows light emitted from the light-emitting element 1 to pass through and be released to the outside. The light-transmitting component 7 may contain a light-diffusing material or a phosphor capable of wavelength conversion of at least a portion of the incident light. The light-transmitting component 7 can be formed, for example, from resin, glass, or inorganic materials. Examples of light-transmitting components containing phosphors include sintered bodies of phosphors and components containing phosphors in resin, glass, ceramics, or other inorganic materials. Alternatively, it may be a component formed by forming a resin layer containing a phosphor on the surface of a molded body such as resin, glass, or ceramics. The thickness of the light-transmitting component 7 is, for example, about 50 to 300 μm.

[0135] For example, the bonding between the light-transmitting component 7 and the light-emitting element can be performed via the light-guiding component described later. Alternatively, in the bonding between the light-transmitting component and the light-emitting element, direct bonding methods utilizing pressing, sintering, surface activation bonding, atomic diffusion bonding, and hydroxyl bonding can be used.

[0136] (Fluorescent material)

[0137] The phosphor that can be included in the light-transmitting component 7 is a phosphor that can be excited by light from the light-emitting element. Examples of phosphors that can be excited by blue or ultraviolet light-emitting elements include: cerium-activated yttrium aluminum garnet phosphors (Ce:YAG); cerium-activated lutetium aluminum garnet phosphors (Ce:LAG); nitrogen-containing calcium aluminum silicate phosphors (CaO-Al2O3-SiO2) activated by europium and / or chromium; silicate phosphors ((Sr,Ba)2SiO4) activated by europium; nitride phosphors such as β-thionyl phosphometers, CASN phosphors, and SCASN phosphors; KSF phosphors (K2SiF6:Mn); sulfide phosphors; and quantum dot phosphors. By combining these phosphors with blue or ultraviolet light-emitting elements, light-emitting devices of various colors (e.g., white light-emitting devices) can be manufactured.

[0138] (Covering component 5)

[0139] The covering member 5 covers the sides of the light-emitting element 1 and the light-transmitting member 7. The covering member 5 can be formed, for example, of a reflective material with high light reflectivity. Specifically, the covering member 5 can be made of a reflective material with a reflectivity of 60% or more, more preferably 80% or 90% or more, to light from the light-emitting element. The reflective material is, for example, made of a resin containing a reflective substance.

[0140] The resin constituting the base material of the covering component 5 can be a silicone resin, a modified silicone resin, an epoxy resin, a modified epoxy resin, an acrylic resin, or a mixed resin containing at least one of these resins. It can be formed by including a reflective material in the base material composed of this resin. As the reflective material, oxides containing any one of Ti, Zr, Nb, Al, and Si, or AlN, MgF, etc., can be used. Titanium dioxide (TiO2) is preferred. Furthermore, it is preferable that particles with a refractive index different from that of the base material resin are dispersed in the base material resin as the reflective material. Since the amount of light reflected and transmitted varies depending on the concentration and density of the reflective material, the concentration and density can be appropriately adjusted according to the shape and size of the light-emitting device.

[0141] (Light guide component 40)

[0142] The light-emitting device may also have a light guide member 40 covering the side surface of the light-emitting element 1. When a portion of the upper surface of the light-emitting element 1 is exposed from the light-transmitting member 7, the light guide member 40 preferably covers the exposed upper surface of the light-emitting element from the light-transmitting member 7. Furthermore, the light guide member 40 preferably covers the exposed lower surface of the light-transmitting member 7 from the light-emitting element 1. Note that the light guide member 40 can also be used as an adhesive member that enters between the light-emitting element and the light-transmitting member 7 to join the two. By having such a light guide member 40, emitted light from the upper surface and side surface of the light-emitting element 1 can be reflected on the outer surface of the light guide member 40, guiding the reflected light towards the light-transmitting member 7.

[0143] From the perspective of ease of handling and processing, the light guide component 40 is preferably made of a resin material. As the resin material, a resin material composed of one or more resins or mixed resins selected from silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, acrylic resin, and fluoropolymer resin can be used. The light guide component 40 can be formed by utilizing the adhesiveness of the resin material used to form the light guide component 40 and the wettability of the resin material with the light-emitting element 1.

[0144] The light-emitting device may also have other components such as protective elements and electronic devices. These components and electronic devices are preferably embedded in the covering component 5.

Claims

1. A light-emitting device, characterized in that, have: substrate; At least one light-emitting element is disposed on the substrate; A plate-shaped light-transmitting component, comprising a phosphor, is disposed with its lower surface facing the upper surface of the light-emitting element, which serves as the light-emitting surface; A covering component that exposes the upper surface of the light-transmitting component and covers the light-emitting element and the light-transmitting component; The upper surface of the light-emitting element is a rectangular shape with a first and a second side facing each other, and a third and a fourth side facing each other. The upper surface of the light-transmitting component is a rectangular shape with a fifth and a sixth side facing each other, and a seventh and a eighth side facing each other. When viewed from above, the fifth side of the light-transmitting component is located outside the first side of the light-emitting element, and the sixth side is located between the first and second sides of the light-emitting element. The lower surface of the light-transmitting component covers the entire upper surface of the light-emitting element.

2. The light-emitting device as described in claim 1, characterized in that, The light-transmitting component includes a second upper surface that is lower than the upper surface on the outer side of the upper surface, and the second upper surface is covered by the covering component.

3. The light-emitting device as described in claim 2, characterized in that, The second upper surface has an inclined surface that is inclined relative to the lower surface.

4. The light-emitting device as described in claim 2, characterized in that, The second upper surface has a surface parallel to the lower surface of the light-transmitting component.

5. The light-emitting device as described in any one of claims 1 to 4, characterized in that, The seventh and eighth sides of the light-transmitting component are located outside the third and fourth sides of the light-emitting element.

6. The light-emitting device according to any one of claims 1 to 4, characterized in that, The seventh and eighth sides of the light-transmitting component are located inside the third and fourth sides of the light-emitting element.

7. The light-emitting device according to any one of claims 1 to 4, characterized in that, The seventh side of the light-transmitting component is located between the third side and the fourth side, and the eighth side is located outside the fourth side.

8. The light-emitting device according to any one of claims 1 to 7, characterized in that, The light-emitting device includes a plurality of light-emitting elements, each having a first side to a fourth side. The plurality of light-emitting elements are arranged on the substrate such that the first side is located on a first straight line and the second side is located on a second straight line parallel to the first straight line.

9. The light-emitting device as described in claim 8, characterized in that, In the light-transmitting component, one light-transmitting component covers multiple light-emitting elements.

10. The light-emitting device according to any one of claims 1 to 9, characterized in that, The covering component is a reflective component containing white pigment.

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