Light-emitting device

Abstract

To reduce color difference when driven by a plurality of circuits on a light-emitting device having a plurality of light-emitting elements.SOLUTION: The light-emitting device includes a substrate, a frame part arranged on the upper surface of the substrate, a first light-emitting element arranged in a first region along the inner edge of the frame part on the upper surface of the substrate, a second light-emitting element arranged in a second region surrounded by the first region on the upper surface of the substrate, a wall part arranged on the upper surface of the substrate, in contact with the frame part, and extending toward the second region from the inner edge of the frame part in a plan view, a wavelength conversion member arranged in a region surrounded by the frame part on the upper surface of the substrate, for coating the wall part, the first light-emitting element, and the second light-emitting element, and a circuit including a first drive circuit driving the first light-emitting element and a second drive circuit driving the second light-emitting element.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a light-emitting device.

Background Art

[0002] There is known a light-emitting device including a first frame portion provided on a substrate, a second frame portion provided on the substrate and surrounding the first frame portion, at least one first light-emitting element provided on the substrate inside the first frame portion, and a plurality of second light-emitting elements provided on the substrate between the first frame portion and the second frame portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present disclosure is to reduce a chromaticity difference when driving a plurality of light-emitting elements in a light-emitting device having a plurality of circuits.

Means for Solving the Problems

[0005] A light-emitting device according to an embodiment of the present disclosure includes a substrate, a frame portion disposed on an upper surface of the substrate, a first light-emitting element disposed in a first region along an inner edge of the frame portion on the upper surface of the substrate, a second light-emitting element disposed in a second region surrounded by the first region on the upper surface of the substrate, a wall portion disposed on the upper surface of the substrate, in contact with the frame portion, and extending from the inner edge of the frame portion toward the second region in a plan view, a wavelength conversion member disposed in a region surrounded by the frame portion on the upper surface of the substrate and covering the wall portion, the first light-emitting element, and the second light-emitting element, a first driving circuit that drives the first light-emitting element, and a second driving circuit that drives the second light-emitting element, and a circuit including the same.

Effects of the Invention

[0006] According to an embodiment of the present disclosure, in a light-emitting device having a plurality of light-emitting elements, it is possible to reduce the chromaticity difference when driving with a plurality of circuits.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the following description, terms indicating a specific direction or position (for example, "up", "down", and other terms including those terms) are used as necessary. However, the use of those terms is for facilitating the understanding of the invention with reference to the drawings, and the technical scope of the present invention is not limited by the meanings of those terms. Also, parts denoted by the same reference numerals in a plurality of drawings indicate the same or equivalent parts or members.

[0009] In addition, the embodiments described below exemplify a light-emitting device or the like for embodying the technical idea of the present invention, and do not limit the present invention thereto. Further, the dimensions, materials, shapes, relative arrangements, etc. of the components described below are not intended to limit the scope of the present invention only thereto, but are intended to be exemplified unless otherwise specifically described. Also, the content described in one embodiment is applicable to other embodiments and modifications. In addition, the sizes and positional relationships of the members shown in the drawings may be exaggerated for clarity of explanation. Further, in order to avoid excessive complexity of the drawings, a schematic diagram in which the illustration of some elements is omitted or an end view showing only the cut surface as a cross-sectional view may be used. Also, in this specification, "rectangle" means that a variation of ±5 degrees is allowed for the angles of the four corners, and includes shapes approximating these rectangles, such as chamfered or rounded corners of the rectangle.

[0010] <First Embodiment> FIG. 1 is a perspective view exemplifying a light-emitting device according to the first embodiment. FIG. 2 is a perspective view of the light-emitting device shown in FIG. 1 with the wavelength conversion member removed. FIG. 3 is a partial plan view exemplifying the frame portion and the inside thereof of the light-emitting device shown in FIG. 2. FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3. FIG. 5 is a cross-sectional view taken along line V-V of FIG. 3. FIG. 6 is a circuit diagram of the light-emitting device according to the first embodiment. Note that in FIGS. 4 and 5, the wavelength conversion member not shown in FIG. 3 is shown.

[0011] The light-emitting device according to the first embodiment includes a substrate, a frame portion, one or more first light-emitting elements, one or more second light-emitting elements, a wall portion, a wavelength conversion member, and a circuit. The light-emitting device according to the first embodiment can be used, for example, in lighting devices such as stop lamps and / or tail lamps of automobiles, motorcycles, etc.

[0012] The light-emitting device 1 illustrated in FIGS. 1 to 6 includes a substrate 10, a frame portion 20, first light-emitting elements 30a to 30d, second light-emitting elements 40a and 40b, a wall portion 50, a wavelength conversion member 60, and a circuit 70. In cases where no particular distinction is required, the first light-emitting elements 30a to 30d may be collectively referred to as the first light-emitting element 30, and the second light-emitting elements 40a and 40b may be collectively referred to as the second light-emitting element 40.

[0013] As shown in FIGS. 1 and 2, the substrate 10 is, for example, rectangular in plan view. On the upper surface 10a of the substrate 10, a frame portion 20, first light-emitting elements 30, second light-emitting elements 40, a wall portion 50, a wavelength conversion member 60, and a circuit 70 are arranged. The circuit 70 has, for example, a plurality of electronic components that are rectangular in plan view.

[0014] In the example of FIGS. 1 to 5, the frame portion 20 is rectangular in plan view. By doing so, a plurality of electronic components that are rectangular in plan view can be efficiently arranged on the upper surface 10a of the substrate 10 along the outer edge of the frame portion 20. Note that the frame portion 20 may be circular or elliptical in plan view.

[0015] As shown in FIG. 3, the upper surface 10a of the substrate 10 has a first region R1 and a second region R2 inside the frame portion 20 in plan view as regions where light-emitting elements are arranged. The first region R1 is a frame-shaped region along the inner edge of the frame portion 20 in plan view. The second region R2 is a region surrounded by the first region R1 and is a region including the center of the frame portion 20 in plan view. In FIG. 3, B indicates the boundary between the first region R1 and the second region R2. In FIG. 3, the two-dot chain line indicating the boundary B is a virtual line for convenience of explanation.

[0016] The first light-emitting element 30 is arranged in the first region R1 on the upper surface 10a of the substrate 10. The first light-emitting elements 30a to 30d can each be, for example, substantially the same size and rectangular in plan view. For example, the plan view shape of the first light-emitting elements 30a to 30d is a square with a side length of about 1 mm. In the light-emitting device 1, the first light-emitting elements 30a to 30d are, for example, connected in series with each other.

[0017] When the light-emitting device 1 includes a plurality of first light-emitting elements 30 having a rectangular shape in plan view and the frame portion 20 is rectangular in plan view, it is preferable that the plurality of first light-emitting elements 30 are arranged at the corners of the rectangle. The length of each side constituting the rectangular frame portion 20 can be about 3 mm or more and 8 mm or less, although it also depends on the size of the desired light-emitting surface. When the light-emitting device 1 includes four first light-emitting elements 30a to 30d, as shown in FIG. 3, it is preferable that the first light-emitting elements 30a to 30d are respectively arranged at the rectangular corners of the frame portion 20. By doing so, it is possible to easily arrange the four first light-emitting elements 30a to 30d in a small space inside the rectangular frame portion 20. Note that the fact that the first light-emitting element 30 is arranged at the corner of the rectangle means that one of the four rectangular first light-emitting elements 30a to 30d is arranged in each of the four rectangular regions obtained by equally dividing the rectangle into two rows and two columns in plan view. At that time, it is preferable that two sides constituting the inner edge of the rectangular frame portion 20 in plan view and two sides of the first light-emitting element 30 facing the inner edge are arranged substantially parallel to each other.

[0018] When the light-emitting device 1 includes a plurality of first light-emitting elements 30 and the frame portion 20 is rectangular in plan view, in the first region R1, it is preferable that the plurality of first light-emitting elements 30 are arranged so as to form a rectangle as a whole in plan view. By doing so, it is possible to easily arrange the plurality of first light-emitting elements 30 (first light-emitting elements 30a to 30d) in a small space inside the rectangular frame portion 20.

[0019] For example, the first light-emitting elements 30 can be arranged in a matrix so as to have a rectangular shape similar to the rectangular region surrounded by the frame portion 20 as a whole. In the example of FIG. 3, the first light-emitting elements 30a to 30d having a rectangular shape in plan view are arranged in two rows and two columns so as to form a rectangle E as a whole in plan view.

[0020] The second light-emitting element 40 is disposed in the second region R2 on the upper surface 10a of the substrate 10. That is, the second light-emitting element 40 is disposed inside the first light-emitting element 30 on the upper surface 10a of the substrate 10. The second light-emitting elements 40a and 40b can each have a substantially the same size and a rectangular shape in plan view, for example. In plan view, it is preferable that the area of one second light-emitting element 40 is smaller than the area of one first light-emitting element 30. Thereby, it is possible to easily arrange the second light-emitting element 40 in a smaller space inside the first light-emitting element 30. For example, the plan-view shapes of the second light-emitting elements 40a and 40b are squares with one side being about 0.6 mm. The second light-emitting elements 40a and 40b are connected in series with each other, for example.

[0021] In the second region R2, it is preferable that one or a plurality of second light-emitting elements 40 are arranged so as to be rectangular as a whole in plan view. Thereby, it is possible to easily arrange the second light-emitting element 40 in a smaller space inside the first light-emitting element 30. In the example of FIG. 3, the second light-emitting elements 40a and 40b overlap a rectangle F whose three sides forming the outer edge are indicated by broken lines, and are arranged so as to be rectangular as a whole in plan view. In plan view, it is preferable that the centers of the rectangle E and the rectangle F overlap. Thereby, since the light-emitting centers of the first light-emitting elements 30a to 30d and the second light-emitting elements 40a and 40b can be made the same, the design of an optical system such as a lens becomes easy. In FIG. 3, the broken lines indicating the rectangle E and the rectangle F are virtual lines for convenience of explanation.

[0022] The wall portion 50 is in contact with the frame portion 20 on the upper surface 10a of the substrate 10 and is arranged to extend from the inner edge of the frame portion 20 toward the second region R2 in plan view. The number of wall portions 50 may be one or a plurality. When the light-emitting device 1 includes a plurality of wall portions 50 and the frame portion 20 is rectangular in plan view, it is preferable that the plurality of wall portions 50 extend from two opposite sides of the rectangle in plan view toward the second region R2, respectively.

[0023] In the example of FIG. 3, the wall portion 50 includes four wall portions 50, each of which is disposed one by one between adjacent first light-emitting elements 30 in a plan view. Specifically, one wall portion 50 is disposed between the first light-emitting element 30a and the first light-emitting element 30b, between the first light-emitting element 30a and the first light-emitting element 30c, between the first light-emitting element 30b and the first light-emitting element 30d, and between the first light-emitting element 30c and the first light-emitting element 30d. That is, the wall portion 50 includes four wall portions that respectively extend from the four sides of the rectangle of the frame portion 20 toward the second region R2. Note that the wall portion 50 may be disposed on all of the opposing side surfaces between adjacent first light-emitting elements 30, or may be disposed up to the middle of the opposing side surfaces between adjacent first light-emitting elements 30.

[0024] The wavelength conversion member 60 is disposed in the region surrounded by the frame portion 20 on the upper surface 10a of the substrate 10, and covers the wall portion 50, the first light-emitting element 30, and the second light-emitting element 40. Further, the wavelength conversion member 60 covers the inner edge of the frame portion 20 and covers at least a part of the height direction continuous with the inner edge of the frame portion 20. Note that the outer edge of the frame portion 20 is exposed from the wavelength conversion member 60. The upper surface of the wavelength conversion member 60 constitutes the light-emitting surface of the light-emitting device 1. The wavelength conversion member 60 is, for example, substantially rectangular in a plan view. The upper surface of the wavelength conversion member 60 is located above the upper surface of the frame portion 20. The wavelength conversion member 60 has translucency so that the light emitted from the first light-emitting element 30 and the second light-emitting element 40 can pass through. The wavelength conversion member 60 can contain a wavelength conversion material such as phosphor particles. For example, in the light-emitting device 1, the first light-emitting element 30 and the second light-emitting element 40 are light-emitting elements that emit blue light, and the wavelength conversion member 60 contains phosphor particles that are excited by the blue light and emit red light. Thereby, the light-emitting device 1 can be a light-emitting device that emits red light. The light-emitting device 1 can be used, for example, in lighting devices such as stop lamps and / or tail lamps of automobiles, motorcycles, etc.

[0025] The circuit 70 includes wirings and electronic components arranged on the substrate 10. As shown in FIG. 6, the circuit 70 includes a first drive circuit 71 that drives the first light-emitting element 30 and a second drive circuit 72 that drives the second light-emitting element 40. The circuit 70 includes electronic components 71i to 71n that constitute the first drive circuit 71 and electronic components 72a to 72c that constitute the second drive circuit 72. The circuit 70 may have electronic components other than the electronic components 71i to 71n and the electronic components 72a to 72c. In the circuit 70, the first drive circuit 71 and the second drive circuit 72 can be independently driven. That is, the circuit 70 can cause the first light-emitting element 30 and the second light-emitting element 40 to emit light simultaneously, or can cause them to emit light at different timings. The first light-emitting element 30 is used, for example, as a stop lamp of an automobile, and the second light-emitting element 40 can be used, for example, as a tail lamp of an automobile.

[0026] The light-emitting device 1 is preferably connected to the circuit 70 and has three or more connection terminals arranged along the outer edge of the upper surface 10a of the substrate 10 in a plan view. By the light-emitting device 1 having three or more connection terminals, it becomes possible to independently drive the first light-emitting element 30 and the second light-emitting element 40. Further, by arranging a plurality of connection terminals along the outer edge of the upper surface 10a, for example, when arranging a heat sink directly below a light source or an electronic component mounted on the substrate 10, it becomes difficult for the heat sink and the plurality of connection terminals to interfere with each other.

[0027] In the example of FIG. 1, three connection terminals 15a, 15b, and 15c are arranged along the first side 10s located at the outer edge of the upper surface 10a in a plan view and are connected to the wiring. The first side 10s constitutes one side of a rectangle in the substantially rectangular upper surface 10a. The connection terminals 15a, 15b, and 15c can be provided, for example, around a through hole 10x penetrating the substrate 10, respectively.

[0028] The connection terminals 15a and 15c are, for example, power input terminals, and the connection terminal 15b is, for example, a GND terminal. The connection terminals 15a, 15b, and 15c can be made of a conductive material such as a metal like gold, silver, copper, or aluminum. When mounting the light-emitting device 1 on a socket or the like, an external plug (for example, a power supply terminal) can be passed through each through-hole 10x and electrically connected to the connection terminals 15a, 15b, and 15c. Note that four or more connection terminals may be arranged along the outer edge of the upper surface 10a in a plan view.

[0029] As described above, the light-emitting device 1 is in contact with the frame portion 20 and includes a wall portion 50 that extends from the inner edge of the frame portion 20 toward the second region R2 in a plan view. Thereby, it is possible to make it difficult for a chromaticity difference to occur in the emitted light of the light-emitting device 1 when only the first light-emitting element 30 emits light and when only the second light-emitting element 40 emits light. This will be described in detail below.

[0030] In the light-emitting device 1, the first light-emitting element 30 is disposed in a first region along the inner edge of the frame portion 20, and the second light-emitting element 40 is located closer to the center of the frame portion 20 than the first light-emitting element 30. And the wavelength conversion member 60 covers the first light-emitting element 30 and the second light-emitting element 40. Therefore, if the light-emitting device 1 does not include the wall portion 50, when only the second light-emitting element 40 emits light, the light traveling in the lateral direction (that is, the direction from the second light-emitting element 40 toward the frame portion 20) among the light emitted from the second light-emitting element 40 has a longer distance to travel through the wavelength conversion member 60 and reach the frame portion 20.

[0031] Here, a case will be described by taking as an example the case where the second light-emitting element 40 emits blue light and the wavelength conversion material contained in the wavelength conversion member 60 is a red phosphor. For example, the absorption spectrum of the red phosphor has a peak near 450 nm which is in the wavelength range of blue light, absorbs the blue light emitted by the second light-emitting element 40, and emits red light excited by the blue light. Thereby, the light-emitting device 1 having a red emission color can be obtained. Here, in the absorption spectrum and emission spectrum of the phosphor, there is an overlapping region between the long-wavelength side region of the absorption spectrum and the short-wavelength side region of the emission spectrum. For this reason, when the distance that the light wavelength-converted by the red phosphor propagates in the wavelength conversion member 60 is long, among the wavelength-converted red light, the red light closer to the short wavelength is further wavelength-converted by the red phosphor. That is, the longer the distance from when only the second light-emitting element 40 emits light until the emitted light from the second light-emitting element 40 reaches the frame portion 20, the larger the ratio of the component on the short-wavelength side of the red light that is absorbed. As a result, in the red light emitted from the upper surface of the wavelength conversion member 60, the red emitted light closer to the short wavelength in the emission spectrum of the red phosphor decreases, and the red light closer to the long wavelength is more likely to be emitted.

[0032] On the other hand, since the first light-emitting element 30 is located near the frame portion 20, the distance from when the light is emitted from the first light-emitting element 30 until it reaches the frame portion 20 is shorter than the light emitted from the second light-emitting element 40. Therefore, the ratio of the component on the short-wavelength side of the red light absorbed by the light emitted from the first light-emitting element 30 is smaller than that of the light emitted from the second light-emitting element 40. As a result, when only the second light-emitting element 40 emits light, the emission spectrum of the red light emitted from the light-emitting device 1 becomes closer to the emission spectrum of the red phosphor than when only the first light-emitting element 30 emits light. That is, there is a chromaticity difference in the emitted light of the light-emitting device 1 between the case where only the first light-emitting element 30 emits light and the case where the second light-emitting element 40 emits light.

[0033] On the other hand, in the light-emitting device 1, a wall portion 50 is disposed in contact with the frame portion 20 and extending from the inner edge of the frame portion 20 toward the second region R2 in plan view. Therefore, a part of the light emitted from the second light-emitting element 40 and traveling toward the frame portion 20 reaches the wall portion 50 before reaching the frame portion 20. As a result, the distance that the light emitted from the second light-emitting element 40 and traveling toward the frame portion 20 travels through the wavelength conversion member 60 is shortened, so that the ratio of the components on the short-wavelength side of the red light being absorbed can be reduced. Consequently, it is possible to make it difficult for a chromaticity difference to occur in the emitted light of the light-emitting device 1 between the case where only the first light-emitting element 30 emits light and the case where only the second light-emitting element 40 emits light. The chromaticity difference between the case where only the first light-emitting element 30 emits light and the case where only the second light-emitting element 40 emits light can be adjusted, for example, by the number, width, length, etc. of the wall portions 50.

[0034] In addition, among the light emitted from the first light-emitting element 30 and the second light-emitting element 40 and traveling in the horizontal direction or the diagonal direction, the light is reflected by the wall portion 50 and travels upward, so that the light extraction efficiency in the light-emitting device 1 can be improved.

[0035] The light-emitting device 1 in the present embodiment includes a first light-emitting element 30, a second light-emitting element 40, and a wavelength conversion member 60. The light emitted from the light-emitting device 1 includes the light emitted from the first light-emitting element 30 and the second light-emitting element 40 and wavelength-converted by the wavelength conversion member 60. Thus, for example, the light-emitting device 1 has light-emitting elements that emit blue light as the first light-emitting element 30 and the second light-emitting element 40, and the wavelength conversion member 60 contains phosphor particles that are excited by blue light and emit red light, so that red light can be emitted. On the other hand, as a light-emitting device that emits red light, a light-emitting device using a light-emitting element that emits red light is used in many fields. In the present embodiment, by using blue light-emitting diodes as the first light-emitting element 30 and the second light-emitting element 40, good temperature characteristics can be obtained as compared with the case of using red light-emitting diodes as the first light-emitting element 30 and the second light-emitting element 40. That is, when the light-emitting device 1 is used as an illumination device for a vehicle or the like, the ambient temperature of use of the first light-emitting element 30 and the second light-emitting element 40 may reach a high temperature exceeding 100°C. Generally, since the luminous flux maintenance rate of a blue light-emitting diode at high temperatures is higher than that of a red light-emitting diode, higher luminance can be maintained during high-temperature operation than in the case of using a red light-emitting diode.

[0036] Note that in the present embodiment, the first light-emitting element 30 and the second light-emitting element 40 are not limited to light-emitting elements that emit blue light, and light-emitting elements that emit desired light such as ultraviolet light and green light can be used. Further, the phosphor contained in the wavelength conversion member 60 is not limited to a phosphor that is excited by blue light and emits red light, and a phosphor that can be excited by the light emitted from the first light-emitting element 30 and the second light-emitting element 40 and emits light can be used. The light-emitting device 1 can be made into a light-emitting device with a desired emission color by combining the emitted light of the first light-emitting element 30 and the second light-emitting element 40 with the phosphor contained in the wavelength conversion member 60.

[0037] Hereinafter, each element constituting the light-emitting device 1 according to the embodiment will be described in detail.

[0038] [Substrate 10] The substrate 10 is a flat member having insulating properties. The substrate 10 has an upper surface 10a. The upper surface 10a is, for example, square or rectangular. The length of each side of the upper surface 10a can be, for example, about 1 cm or more and 3 cm or less. When the upper surface 10a is square or rectangular, chamfers or the like may be provided at each corner of the square or rectangle. Note that the upper surface 10a may be circular or polygonal.

[0039] The substrate 10 is made of a ceramic material such as aluminum oxide, aluminum nitride, or silicon nitride, for example. The substrate 10 may be made of an insulating resin material such as phenolic resin, epoxy resin, polyimide resin, BT resin, or polyphthalamide. The substrate 10 may be one in which an insulating member is disposed on the surface of a metal member.

[0040] On the upper surface 10a of the substrate 10, wirings and component mounting lands connected to the wirings are disposed. The wirings and lands can be made of a material having conductivity such as a metal such as gold, silver, copper, or aluminum.

[0041] The light-emitting device 1 may be provided with a solder resist layer on the upper surface 10a of the substrate 10 that covers the wirings and exposes the lands and the connection terminals 15a, 15b, and 15c. The solder resist layer can be disposed, for example, with a photosensitive insulating resin or the like.

[0042] [Frame portion 20] The frame portion 20 is disposed on the upper surface 10a of the substrate 10. The region surrounded by the frame portion 20 is the light-emitting surface of the light-emitting device 1, and the light-emitting surface of the light-emitting device 1 is defined by the frame portion 20. Further, the frame portion 20 can be used as a dam for blocking the uncured wavelength conversion member 60 in the manufacturing process of the light-emitting device 1. The frame portion 20 surrounds the first light-emitting element 30 and the second light-emitting element 40 in a plan view. In a plan view, the width between the outer edge and the inner edge of the frame portion 20 can be, for example, about 0.3 mm or more and 1 mm or less. The height of the frame portion 20 from the upper surface 10a of the substrate 10 can be, for example, about 0.3 mm or more and 1 mm or less.

[0043] The frame portion 20 can be, for example, rectangular in plan view. For example, if the frame portion 20 is circular in plan view, the distances between the four corner portions of the rectangle E shown in FIG. 3 and the inner edge of the frame portion 20 are closer than the distances between the four sides of the rectangle E and the inner edge of the circular frame portion 20. Therefore, the amount of light emitted from near the four corner portions of the rectangle E in the light-emitting device 1 is less than the amount of light emitted from near the four sides of the rectangle E, resulting in uneven brightness. If the frame portion 20 is rectangular in plan view, uneven brightness can be less likely to occur.

[0044] The frame portion 20 contains, for example, a resin. Examples of the resin include known resins having translucency such as silicone resins and epoxy resins. Among them, a translucent resin of a silicone resin (specifically, phenyl silicone resin, dimethyl silicone resin, etc.) with excellent reliability can be preferably used. The frame portion 20 preferably has light-shielding properties. In order to impart light-shielding properties to the frame portion 20, a resin in which a pigment is added to the above-mentioned translucent resin can be used. Among them, the frame portion 20 preferably has light reflectivity, and in the frame portion 20, a filler such as a white pigment may be added to the resin to enhance the reflectivity. As the filler, titanium oxide, aluminum oxide, zinc oxide, barium carbonate, barium sulfate, boron nitride, aluminum nitride, glass filler, etc. can be preferably used. Further, the frame portion 20 may further contain a black pigment such as carbon black, graphite, and titanium black.

[0045] [First light-emitting element 30, second light-emitting element 40] The first light-emitting element 30 and the second light-emitting element 40 are mounted on the lands for component mounting on the substrate 10. The first light-emitting element 30 and the second light-emitting element 40 are preferably flip-chip mounted on the substrate 10. In flip-chip mounting, the electrodes of the first light-emitting element 30 and the second light-emitting element 40 and the lands on the substrate 10 can be electrically joined using a joining member such as eutectic solder, conductive paste, and bumps.

[0046] The first light-emitting element 30 and the second light-emitting element 40 are light-emitting diodes. The specific configurations of the first light-emitting element 30 and the second light-emitting element 40 may be arbitrary as long as they can emit light of a predetermined wavelength. For example, the first light-emitting element 30 and the second light-emitting element 40 may be those in which an LED chip is housed in a package, or may be a single LED chip (bare chip). Among them, it is preferable that the first light-emitting element 30 and the second light-emitting element 40 are those in which bare chips are flip-chip mounted on the substrate 10. Thereby, miniaturization of the light-emitting device 1 becomes possible.

[0047] The first light-emitting element 30 and the second light-emitting element 40 include a semiconductor structure. The semiconductor structure includes an n-side semiconductor layer, a p-side semiconductor layer, and an active layer sandwiched between the n-side semiconductor layer and the p-side semiconductor layer. The active layer may have a single quantum well (SQW) structure or a multiple quantum well (MQW) structure including a plurality of well layers. The semiconductor structure includes a plurality of semiconductor layers made of a nitride semiconductor. The nitride semiconductor includes semiconductors of all compositions in which the composition ratios x and y are changed within their respective ranges in the chemical formula consisting of In x Al y Ga 1-x-y N (0≦x, 0≦y, x + y≦1). The emission peak wavelength of the active layer can be appropriately selected according to the purpose. The active layer is configured to emit, for example, visible light or ultraviolet light.

[0048] The semiconductor structure may include a plurality of light-emitting portions each including an n-side semiconductor layer, an active layer, and a p-side semiconductor layer. When the semiconductor structure includes a plurality of light-emitting portions, each light-emitting portion may include well layers having different emission peak wavelengths, or may include well layers having the same emission peak wavelength. Note that the case where the emission peak wavelengths are the same includes a case where there is a variation of about several nm. The combination of the emission peak wavelengths of the plurality of light-emitting portions can be appropriately selected. For example, when the semiconductor structure includes two light-emitting portions, examples of the combination of the light emitted from each light-emitting portion include combinations such as blue light and blue light, green light and green light, ultraviolet light and ultraviolet light, blue light and green light, blue light and ultraviolet light, or green light and ultraviolet light. For example, when the semiconductor structure includes three light-emitting portions, an example of the combination of the light emitted from each light-emitting portion is a combination of blue light, green light, and red light. Each light-emitting portion may include one or more well layers having an emission peak wavelength different from that of other well layers.

[0049] The wavelengths of the light emitted from the first light-emitting element 30 and the second light-emitting element 40 are appropriately set according to the use of the light-emitting device 1. The first light-emitting element 30 and the second light-emitting element 40 are, for example, blue light-emitting elements that emit blue light. When the first light-emitting element 30 and the second light-emitting element 40 are light-emitting elements of a nitride-based semiconductor that emits blue light, the forward voltage of the first light-emitting element 30 and the second light-emitting element 40 is, for example, 2.6 V or more.

[0050] [Wall portion 50] The height of the wall portion 50 from the upper surface 10a of the substrate 10 is preferably lower than the height of the frame portion 20. Thereby, the light wavelength-converted by the wavelength conversion member 60 can be preferably reflected upward by the wall portion 50, so that the light extraction efficiency in the light-emitting device 1 can be improved. The height of the wall portion 50 from the upper surface 10a of the substrate 10 can be, for example, about 0.1 mm or more and 0.8 mm or less lower than the height of the frame portion 20 from the upper surface 10a of the substrate 10.

[0051] Further, the wall portion 50 has a top portion and an inclined surface extending from the top portion toward the substrate 10 side, and the inclined surface preferably includes a convex curved surface on the outside. For example, the wall portion 50 is preferably semi-circular or semi-elliptical in cross-section. Thereby, since the light wavelength-converted by the wavelength conversion member 60 can be reflected more upward by the wall portion 50, the light extraction efficiency in the light-emitting device 1 can be improved.

[0052] The center line in the longitudinal direction of the wall portion 50 (that is, the direction in which the wall portion 50 extends from the inner edge of the frame portion 20 toward the second region R2) is, for example, parallel or perpendicular to any side constituting the rectangular inner edge of the frame portion 20 in plan view. Here, "parallel" and "perpendicular" are to allow a difference of ±5 degrees. Note that the center line in the longitudinal direction of the wall portion 50 does not have to be parallel or perpendicular to any side constituting the rectangular inner edge of the frame portion 20 in plan view. In plan view, the width of the wall portion 50 can be, for example, about 0.3 mm or more and 1 mm or less.

[0053] The wall portion 50 includes, for example, a resin. The wall portion 50 can use the translucent resin exemplified for the frame portion 20. The wall portion 50 preferably has light-shielding properties. In order to impart light-shielding properties, the wall portion 50 can use a resin in which a pigment is added to the above-described translucent resin. Among them, the wall portion 50 preferably has light-reflecting properties, and in the wall portion 50, a filler such as a white pigment may be added to the resin to enhance the reflectivity. As the filler, the filler exemplified for the frame portion 20 can be used.

[0054] [Wavelength conversion member 60] The wavelength conversion member 60 contains, for example, a resin. As the resin, the translucent resin exemplified in the frame portion 20 can be used. When the wavelength conversion member 60 contains a phosphor, the phosphor is excited by the light emitted from the first light emitting element 30 and the second light emitting element 40, and emits light having a wavelength different from the wavelength of the light emitted from the first light emitting element 30 and the second light emitting element 40. As an example, when the first light emitting element 30 and the second light emitting element 40 are blue light emitting elements, the wavelength conversion member 60 may contain a red phosphor. In this case, the first light emitting element 30 and the second light emitting element 40 emit blue light, and the wavelength conversion member 60 can be excited by the blue light to emit red light. In this case, the light emitting device 1 that emits red light from the light emitting surface can be realized.

[0055] Examples of the phosphor include yttrium aluminum garnet-based phosphors (for example, (Y,Gd)3(Al,Ga)5O 12 :Ce), lutetium aluminum garnet-based phosphors (for example, Lu3(Al,Ga)5O 12 :Ce), terbium aluminum garnet-based phosphors (for example, Tb3(Al,Ga)5O 12 :Ce), CCA-based phosphors (for example, Ca 10 (PO4)6Cl2:Eu), SAE-based phosphors (for example, Sr4Al 14 O 25 :Eu), chlorosilicate-based phosphors (for example, Ca8MgSi4O 16 Cl2:Eu), silicate-based phosphors (for example, (Ba,Sr,Ca,Mg)2SiO4:Eu), β-sialon-based phosphors (for example, (Si,Al)3(O,N)4:Eu) or α-sialon-based phosphors (for example, Ca(Si,Al) 12 (O,N) 16 :Eu) and other oxynitride-based phosphors, LSN-based phosphors (for example, (La,Y)3Si6N 11:(Ce), BSESN-based phosphors (e.g., (Ba,Sr)2Si5N8:Eu), SLA-based phosphors (e.g., SrLiAl3N4:Eu), CASN-based phosphors (e.g., CaAlSiN3:Eu), or SCASN-based phosphors (e.g., (Sr,Ca)AlSiN3:Eu), etc., nitride-based phosphors, KSF-based phosphors (e.g., K2SiF6:Mn), KSAF-based phosphors (e.g., K2(Si 1-x Al x )F 6-x :Mn where x satisfies 0 < x < 1), or fluoride-based phosphors such as MGF-based phosphors (e.g., 3.5MgO·0.5MgF2·GeO2:Mn), quantum dots having a perovskite structure (e.g., (Cs,FA,MA)(Pb,Sn)(F,Cl,Br,I)3 where FA and MA represent formamidinium and methylammonium, respectively), II-VI group quantum dots (e.g., CdSe), III-V group quantum dots (e.g., InP), or quantum dots having a chalcopyrite structure (e.g., (Ag,Cu)(In,Ga)(S,Se)2), etc. can be used.

[0056] As shown in FIGS. 4 and 5, when the wavelength conversion member 60 contains phosphor particles, the phosphor-containing portion 65 in which the phosphor particles are unevenly distributed on the substrate 10 side may be provided. In FIGS. 4 and 5, the broken line indicates the boundary between the phosphor-containing portion 65 and its upper part. In FIGS. 4 and 5, the broken line indicating the boundary is a virtual line for convenience of explanation. The boundary does not have to be linear. In the phosphor-containing portion 65, the phosphor particles can be dispersed substantially uniformly. In the wavelength conversion member 60, above the broken line, no phosphor particles may exist at all, or a smaller proportion of phosphor particles than in the phosphor-containing portion 65 may exist.

[0057] In the phosphor particles contained in the wavelength conversion member 60, it is known that part of the absorbed light is converted into heat. By unevenly distributing the phosphor particles toward the substrate 10 side, the heat generated by the phosphor particles can be efficiently dissipated through the substrate 10. Further, by unevenly distributing the phosphor particles toward the substrate 10 side, the phosphor particles can be arranged close to the first light-emitting element 30 and the second light-emitting element 40. Thereby, the light from the first light-emitting element 30 and the second light-emitting element 40 can be efficiently wavelength-converted.

[0058] To provide the phosphor-containing portion 65, in the step of arranging the wavelength conversion member 60, an uncured resin containing phosphor particles may be arranged inside the frame portion 20, and the phosphor particles may be sedimented on the upper surface 10a side of the substrate 10 within the frame portion 20. For example, if phosphor particles having a specific gravity greater than that of the uncured resin are selected, the phosphor particles can be sedimented before the uncured resin is cured. Further, the phosphor particles may be forcibly sedimented by centrifugal sedimentation or the like.

[0059] The height of the wall portion 50 is preferably less than the height of the phosphor-containing portion 65. Thereby, the light wavelength-converted by the wavelength conversion member 60 can be more reflected upward by the wall portion 50, so that the light extraction efficiency in the light-emitting device 1 can be improved. Further, by not arranging the wall portion 50 between the phosphor particles and the substrate 10, the heat generated by the phosphor particles can be efficiently dissipated through the substrate 10.

[0060] The upper surface of the wavelength conversion member 60 may be convex in a direction away from the upper surface 10a of the substrate 10. Thereby, the light emitted obliquely upward from the first light-emitting element 30 and the second light-emitting element 40 can be refracted in a substantially straight-up direction at the interface between the convex upper surface of the wavelength conversion member 60 and the air, so that the light extraction efficiency in the light-emitting device 1 can be improved.

[0061] [Circuit 70] The electronic component 71l of the first drive circuit 71 is an integrated circuit that drives the first light-emitting element 30. The first light-emitting elements 30a to 30d are connected in series to the output side of the electronic component 71l. It is preferable that a voltage is supplied to the electronic component 71l from the outside without passing through an active element (such as a rectifying diode) that causes a voltage drop. Thereby, more of the voltage supplied from the outside can be used to drive the first light-emitting element 30. When the first light-emitting element 30 is a blue light-emitting diode, since the forward voltage is relatively high, it is significant that a voltage is supplied to the electronic component 71l from the outside without passing through an active element. The first drive circuit 71 can control the value of the current flowing through the first light-emitting element 30 by including an integrated circuit as the electronic component 71l. The electronic component 71l, which is an integrated circuit, can be arranged outside the frame portion 20 on the substrate 10. Thereby, light absorption by the electronic component 71l can be reduced. Further, when the electronic component 71l is rectangular in plan view, it is possible to easily arrange the electronic component in a limited space on the upper surface 10a of the substrate 10 along the frame portion 20.

[0062] The electronic components 71i to 71k are resistors that set the operating voltage of the electronic component 71l. The electronic component 71m is a resistor that sets the output current of the electronic component 71l. The electronic component 71n is a thermistor that detects the ambient temperature of the electronic component 71l. The electronic component 71l can control the value of the current flowing through the first light-emitting element 30 based on the temperature detected by the electronic component 71n, for example, when the temperature of the substrate 10 rises.

[0063] The light-emitting device 1 may have the first light-emitting element 30 connected in parallel to the electronic component 72l, which is an integrated circuit. In the example of FIG. 6, the first light-emitting elements 30a to 30c connected in series with each other and the first light-emitting element 30d are connected in parallel to the electronic component 72l.

[0064] The first drive circuit 71 may have a first operation mode in which all of the first light-emitting elements 30a to 30d emit light simultaneously, and a second operation mode in which only the first light-emitting elements 30a to 30c emit light. The second mode is effective, for example, when the voltage applied between the connection terminal 15a and the connection terminal 15b drops and it becomes difficult to drive the four light-emitting elements simultaneously.

[0065] Note that the first drive circuit 71 may be configured to include an integrated circuit, or may be configured not to include an integrated circuit. When the first drive circuit 71 includes an integrated circuit, a large current can be supplied to the first light-emitting element 30, so the light emission intensity of the first light-emitting element 30 can be increased. When it is not necessary to increase the light emission intensity of the first light-emitting element 30, the first drive circuit 71 may be configured to include, for example, a transistor instead of an integrated circuit, or to apply a voltage supplied from the outside through a resistor to the first light-emitting element 30.

[0066] The circuit 70 may include peripheral circuits of the first drive circuit 71 as needed. In the example of FIG. 6, the circuit 70 includes electronic components 71a to 71h as peripheral circuits of the first drive circuit 71.

[0067] The electronic components 71a and 71b are capacitors for noise countermeasures and are connected in series between the connection terminal 15a and the connection terminal 15b. The electronic components 71a and 71b can reduce, for example, radio wave noise such as radio and noise induced in the cable. The electronic components 71a and 72b are connected on the input side rather than the electronic component 71g. Here, the side closer to the connection terminals 15a and 15b in the circuit 70 is referred to as the input side, and the side closer to the first light-emitting element 30 is referred to as the output side.

[0068] Electronic components 71c to 71f are reverse connection protection circuits and are connected to the output sides of electronic components 71a and 71b which are capacitors. Electronic component 71c is a resistor and controls the current value flowing through electronic component 71d. Electronic component 71d is a field effect transistor (MOSFET) and prevents current from flowing from connection terminal 15b to connection terminal 15a side. Electronic component 71e is a capacitor and protects electronic component 71d when a sudden overvoltage in the reverse direction is applied. Electronic component 71f is a Zener diode and protects so that the voltage applied to the side of electronic component 71e of electronic component 71d does not exceed the maximum rating when current flows from connection terminal 15a to connection terminal 15a side.

[0069] One end of electronic component 71c is connected to connection terminal 15a, and the other end is connected to the gate of electronic component 71d, one end of electronic component 71e, and the cathode of electronic component 71f. Also, the source of electronic component 71d is connected to connection terminal 15b, and the anode of electronic component 71f is connected to the drain of electronic component 71d. In this circuit, since the gate of electronic component 71d is biased, the voltage drop between the drain and source of electronic component 71d becomes small, so that a reverse connection protection circuit with suppressed power consumption can be realized.

[0070] Electronic component 71g is a TVS (Transient Voltage Suppressors) diode that protects other electronic components when an overvoltage is applied and is connected between connection terminal 15a and connection terminal 15b. Electronic component 71g is connected on the output side of electronic components 71c to 71f and on the input side of the first drive circuit 71.

[0071] Electronic component 71h is a capacitor for noise countermeasures and is connected between connection terminal 15a and connection terminal 15b. Electronic component 71h is connected on the output side of electronic components 71c to 71f and on the input side of the first drive circuit 71.

[0072] The second drive circuit 72 is connected in series with the second light-emitting element 40. The electronic component 72a is a rectifying diode, and the anode of the electronic component 72a is connected to the connection terminal 15c. The electronic component 72a can protect the second light-emitting elements 40a and 40b from negative terminal surges, along with protection against reverse connection. The electronic components 72b and 72c are resistors connected between the cathode of the electronic component 72a and the second light-emitting element 40, and adjust the current flowing through the second light-emitting elements 40a and 40b.

[0073] Thus, the second drive circuit 72 does not have an integrated circuit or transistors, and includes the electronic component 72a which is a rectifying diode, and the electronic components 72b and 72c which are resistors connected in series to the cathode of the rectifying diode. The second light-emitting element 40 emits light by the current supplied via the electronic component 72a which is a rectifying diode, and the electronic components 72b and 72c which are resistors.

[0074] The circuit 70 may include a peripheral circuit of the second drive circuit 72 as necessary. In the example of FIG. 6, the circuit 70 includes the electronic components 72d to 72f as a peripheral circuit of the second drive circuit 72. The electronic component 72d is a Zener diode for protecting the second light-emitting element 40 from positive terminal surges, and is connected in series between the connection terminal 15c and the connection terminal 15b. The electronic components 72e and 72f are capacitors for noise countermeasures, and are connected in series between the connection terminal 15c and the connection terminal 15b. The electronic components 72e and 72f can reduce, for example, radio wave noise such as radio, and noise induced in the cable. The electronic components 72e and 72f are connected on the output side rather than the electronic component 72d.

[0075] Note that the circuit configuration shown in FIG. 6 is an example, and the light-emitting device 1 may have another circuit configuration. The circuit configuration provided in the light-emitting device 1 can be appropriately changed according to the use of the light-emitting device 1 and the like.

[0076] Although the preferred embodiments etc. have been described in detail above, the present invention is not limited to the above-described embodiments etc., and various modifications and substitutions can be made to the above-described embodiments etc. without departing from the scope described in the claims.

[0077] In addition to the above embodiments, the following supplementary notes are further disclosed. (Supplementary Note 1) A substrate, A frame portion disposed on the upper surface of the substrate, On the upper surface of the substrate, a first light-emitting element disposed in a first region along the inner edge of the frame portion, On the upper surface of the substrate, a second light-emitting element disposed in a second region surrounded by the first region, On the upper surface of the substrate, a wall portion that contacts the frame portion and extends from the inner edge of the frame portion toward the second region in a plan view, On the upper surface of the substrate, a wavelength conversion member disposed in a region surrounded by the frame portion and covering the wall portion, the first light-emitting element, and the second light-emitting element, A circuit including a first drive circuit that drives the first light-emitting element and a second drive circuit that drives the second light-emitting element, a light-emitting device. (Supplementary Note 2) Including a plurality of the first light-emitting elements, The wall portion is disposed between the adjacent first light-emitting elements in a plan view, the light-emitting device according to Supplementary Note 1. (Supplementary Note 3) The frame portion is rectangular in a plan view, A plurality of the first light-emitting elements are disposed at the corner portions of the rectangle, the light-emitting device according to Supplementary Note 1 or 2. (Supplementary Note 4) The wall portion includes a plurality of wall portions that extend from two opposite sides of the rectangle toward the second region in a plan view, the light-emitting device according to Supplementary Note 3. (Supplementary Note 5) The first light-emitting element includes four first light-emitting elements respectively disposed at the corner portions of the rectangle, The light-emitting device according to appendix 3 or 4, wherein the wall portion includes four wall portions respectively extending from the four sides of the rectangle toward the second region. (Appendix 6) The light-emitting device according to any one of appendices 1 to 5, wherein the height of the wall portion is lower than the height of the frame portion. (Appendix 7) The light-emitting device according to any one of appendices 1 to 6, wherein the area of the second light-emitting element is smaller than the area of the first light-emitting element in plan view. (Appendix 8) The light-emitting device according to any one of appendices 1 to 7, wherein a plurality of the first light-emitting elements are arranged so as to be rectangular as a whole in plan view. (Appendix 9) The light-emitting device according to any one of appendices 1 to 8, wherein one or more of the second light-emitting elements are arranged so as to be rectangular as a whole in plan view. (Appendix 10) The light-emitting device according to any one of appendices 1 to 9, having three or more connection terminals connected to the circuit and arranged along the outer edge of the upper surface of the substrate in plan view. (Appendix 11) The circuit includes an integrated circuit, The light-emitting device according to any one of appendices 1 to 10, having a first light-emitting element connected in parallel to the integrated circuit. (Appendix 12) The light-emitting device according to appendix 11, wherein the integrated circuit is arranged outside the frame portion on the substrate. (Appendix 13) The light-emitting device according to any one of appendices 1 to 12, wherein the wavelength conversion member contains phosphor particles and has a phosphor-containing portion in which the phosphor particles are unevenly distributed on the substrate side. (Appendix 14) The light-emitting device according to appendix 13, wherein the height of the wall portion is less than the height of the phosphor-containing portion. (Appendix 15) The first light-emitting element and the second light-emitting element emit blue light, The light-emitting device according to any one of appendices 1 to 14, wherein the wavelength conversion member is excited by blue light and emits red light.

Description of Symbols

[0078] 1 Light-emitting device 10 Substrate 10a Upper surface 15a, 15b, 15c Connection terminals 20 Frame portion 30, 30a, 30b, 30c, 30d First light-emitting element 40, 40a, 40b Second light-emitting element 50 Wall portion 60 Wavelength conversion member 65 Phosphor-containing portion 70 Circuit 71 First drive circuit 71a~71n Electronic components 72 Second drive circuit 72a~72f Electronic components

Claims

1. A substrate, a frame portion disposed on the upper surface of the substrate, a first light-emitting element disposed in a first region along the inner edge of the frame portion on the upper surface of the substrate, a second light-emitting element disposed in a second region surrounded by the first region on the upper surface of the substrate, a wall portion disposed on the upper surface of the substrate, in contact with the frame portion, and extending from the inner edge of the frame portion toward the second region in a plan view, a wavelength conversion member disposed in the region surrounded by the frame portion on the upper surface of the substrate, and covering the wall portion, the first light-emitting element, and the second light-emitting element, a circuit including a first drive circuit for driving the first light-emitting element and a second drive circuit for driving the second light-emitting element. A light-emitting device comprising:

2. The light-emitting device according to claim 1, further comprising a plurality of the first light-emitting elements, wherein the wall portion is disposed between the adjacent first light-emitting elements in a plan view.

3. The light-emitting device according to claim 1, wherein the frame portion is rectangular in a plan view, and the plurality of the first light-emitting elements are disposed at the corners of the rectangle.

4. The light-emitting device according to claim 3, wherein the wall portion includes a plurality of wall portions extending from two opposite sides of the rectangle toward the second region in a plan view.

5. The light-emitting device according to claim 3, wherein the first light-emitting elements include four first light-emitting elements respectively disposed at the corners of the rectangle, and the wall portion includes four wall portions extending from the four sides of the rectangle toward the second region respectively.

6. The light-emitting device according to any one of claims 1 to 5, wherein the height of the wall portion is lower than the height of the frame portion.

7. The light-emitting device according to any one of claims 1 to 5, wherein in a plan view, the area of the second light-emitting element is smaller than the area of the first light-emitting element.

8. The light-emitting device according to any one of claims 1 to 5, wherein the plurality of the first light-emitting elements are arranged such that they form a rectangle as a whole in a plan view.

9. The light-emitting device according to any one of claims 1 to 5, wherein one or more of the second light-emitting elements are arranged such that they form a rectangle as a whole in a plan view.

10. The light-emitting device according to any one of claims 1 to 5, further comprising three or more connection terminals connected to the circuit and disposed along the outer edge of the upper surface of the substrate in a plan view.

11. The light-emitting device according to any one of claims 1 to 5, wherein the circuit includes an integrated circuit, and the integrated circuit has a first light-emitting element connected in parallel thereto.

12. The light-emitting device according to claim 11, wherein on the substrate, the integrated circuit is disposed outside the frame portion.

13. The light-emitting device according to any one of claims 1 to 5, wherein the wavelength conversion member contains phosphor particles and has a phosphor-containing portion in which the phosphor particles are unevenly distributed on the substrate side.

14. The light-emitting device according to claim 13, wherein the height of the wall portion is less than the height of the phosphor-containing portion.

15. The first light-emitting element and the second light-emitting element emit blue light. The light-emitting device according to any one of claims 1 to 5, wherein the wavelength conversion member is excited by blue light and emits red light.

Images