Light emitting device

Abstract

The present disclosure provides a light-emitting device, including: a substrate; a first light-emitting chip for emitting a first color light, the first light-emitting chip being arranged on the substrate, the first light-emitting chip comprising a first substrate and a first light-emitting layer, the first substrate comprising a first surface and a second surface opposite to the first surface, the first light-emitting layer being located on the first surface; a second light-emitting chip for emitting a second color light different from the first color light, the second light-emitting chip being arranged on the first light-emitting chip, the second light-emitting chip comprising a second substrate and a second light-emitting layer, the second substrate comprising a third surface and a fourth surface opposite to the third surface, the second light-emitting layer being located on the third surface; wherein the second surface is opposite to the fourth surface.

Description

Technical Field

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

[0002] Currently, there is a significant demand for high color rendering index (CRI) light-emitting devices in various applications. Therefore, the current method of using blue light-emitting elements with red and green phosphors to produce blue, red, and green light is insufficient. A more suitable approach is to use blue and green light-emitting elements with red phosphors to generate blue, red, and green light. One important problem to be solved is how to improve the color mura issue between different colors of light, such as blue and green light, within the light-emitting element. Summary of the Invention

[0003] This invention provides a light-emitting device to improve the color mura problem between different colors of light in a light-emitting element.

[0004] A light-emitting device according to the present invention includes: a substrate; a first light-emitting chip for emitting a first color of light, the first light-emitting chip being disposed on the substrate, the first light-emitting chip including a first substrate and a first light-emitting layer, the first substrate including a first surface and a second surface opposite to the first surface, the first light-emitting layer being located on the first surface; and a second light-emitting chip for emitting a second color of light different from the first color of light, the second light-emitting chip being disposed on the first light-emitting chip, the second light-emitting chip including a second substrate and a second light-emitting layer, the second substrate including a third surface and a fourth surface opposite to the third surface, the second light-emitting layer being located on the third surface; wherein the second surface and the fourth surface are opposite each other.

[0005] Based on the above, by attaching the first light-emitting chip to the substrate in a flip-chip manner, and attaching the second light-emitting chip located on the first light-emitting chip to the substrate in a top-mount manner, the color halo phenomenon between different colors of light can be effectively improved. Simple Explanation of the Diagram

[0006] Figure 1 is a schematic diagram of a light-emitting device according to an embodiment of the present invention. Figure 2 is a circuit diagram of a first light-emitting chip and a second light-emitting chip according to an embodiment of the present invention. Figure 3 is a schematic diagram of a light-emitting device according to an embodiment of the present invention. Figures 4 to 9 are flowcharts illustrating the fabrication process of a light-emitting device according to an embodiment of the present invention. Implementation

[0007] Figure 1 is a schematic diagram of a light-emitting device according to an embodiment of the present invention. Please refer to Figure 1. The light-emitting device 100 includes: a substrate 110, a co-metal layer 126, a first light-emitting chip 120, a second light-emitting chip 130, a die-bonding layer 140, a bonding pad 150, and an electrode 160.

[0008] Substrate 110 provides support for light-emitting device 100. Substrate 110 has surfaces 110A and 110B facing each other. A plurality of solder pads 150 are located on surface 110A of substrate 110. A plurality of electrodes are disposed on surface 110B, such as a first anode 160A, a cathode 160B, and a second anode 160C. Parts of the solder pads 150 are electrically connected to parts of the electrodes through substrate 110. In some embodiments, substrate 110 may be a printed circuit board (PCB) or other devices with similar functions, and this disclosure is not limited thereto.

[0009] As shown in Figure 1, the first light-emitting chip 120 is electrically connected to the substrate 110 via a flip-chip method. The second light-emitting chip 130 is electrically connected to the substrate 110 via a top-mount method.

[0010] Specifically, the first light-emitting chip 120 is disposed on the substrate 110 to emit a first color light L1. The first light-emitting chip 120 includes a first substrate 122 and a first light-emitting layer 124.

[0011] The first substrate 122 includes a first surface 122A and a second surface 122B opposite to the first surface 122A. In some embodiments, the first substrate 122 may be made of aluminum oxide, i.e., sapphire, or a material with similar properties, and this disclosure is not limited thereto. In some embodiments, the first substrate 122 is transparent to the first color light L1 to avoid absorbing the first color light L1.

[0012] The first light-emitting layer 124 is located on the first surface 122A and is used to emit a first color light L1. Specifically, the first light-emitting layer 124 of the first light-emitting chip 120 is located between the first substrate 122 and the substrate 110. In some embodiments, the first light-emitting layer 124 includes a plurality of light-emitting elements, such as light-emitting diodes, laser diodes, quantum dots, or other elements with similar properties, and this disclosure is not limited thereto. In some embodiments, the first light-emitting layer 124 is formed on the first surface 122A of the first substrate 122 by epitaxy. Therefore, the first light-emitting layer 124 is easily peeled off from the first surface 122A of the first substrate 122 when subjected to external friction.

[0013] As shown in Figure 1, the eutectic layer 126 is located between the substrate 110 and the first light-emitting chip 120. Therefore, the first light-emitting chip 120 can be electrically connected to the first anode 160A and the cathode 160B via the eutectic layer 126 and the substrate 110, respectively. Thus, the light-emitting state of the first light-emitting layer 124 of the first light-emitting device 120 can be controlled by the first anode 160A and the cathode 160B.

[0014] In some embodiments, the material of the co-gold layer 126 includes indium (In), tin (Sn), copper (Cu), silver (Ag), bismuth (Bi), or alloys thereof, or other suitable materials, and this disclosure is not limited thereto.

[0015] The second light-emitting chip 130 is disposed on the first light-emitting chip 120 to emit a second color light L2 that is different from the first color light L1. The second light-emitting chip 130 includes a second substrate 132 and a second light-emitting layer 134.

[0016] In some embodiments, the first color light L1 is green light and the second color light L2 is blue light. In other embodiments, the first color light L1 is blue light and the second color light L2 is green light. In some embodiments, the wavelength range of blue light is 430~480nm and the wavelength range of green light is 500~560nm.

[0017] The second substrate 132 includes a third surface 132A and a fourth surface 132B opposite to the third surface 132A. In some embodiments, the material of the second substrate 132 may be aluminum oxide, i.e., sapphire, or something with similar properties, and this disclosure is not limited thereto. In some embodiments, the second substrate 132 is transparent to the first color light L1 to avoid absorbing the first color light L1.

[0018] In some embodiments, the orthographic projection of the fourth surface 132B in the vertical direction lies within the second surface 122B. That is, the second substrate 132 is completely located within the first substrate 122.

[0019] In some embodiments, the area of ​​the second surface 122B is larger than that of the fourth surface 132B. The area of ​​the fourth surface 132B is 25% to 80% of the area of ​​the second surface 122B. That is, the second substrate 132 is completely located within the first substrate 122.

[0020] The second light-emitting layer 134 is located on the third surface 132A and is used to emit a second color light L2. Specifically, the second light-emitting layer 134 of the second light-emitting chip 130 is located on the third surface 132A of the second substrate 132 away from the substrate 110. In some embodiments, the second light-emitting layer 134 includes multiple light-emitting elements, such as light-emitting diodes, laser diodes, quantum dots, or other elements with similar properties, and this disclosure is not limited thereto. In some embodiments, the second light-emitting layer 134 is formed on the third surface 132A of the second substrate 132 by epitaxy. Therefore, the second light-emitting layer 134 is easily peeled off from the third surface 132A of the second substrate 132 when subjected to external friction.

[0021] As shown in Figure 1, the second light-emitting chip 130 further includes electrodes 136 located on the second light-emitting layer 134. Therefore, the second light-emitting layer 134 can be electrically connected to the second anode 160C via one electrode 136, one wire 138, one pad 150, and through the substrate 110, and electrically connected to the cathode 160B via the other electrode 136, the other wire 138, the other pad 150, and through the substrate 110. Thus, the light-emitting state of the second light-emitting layer 134 of the second light-emitting device 130 can be controlled by the second anode 160C and the cathode 160B.

[0022] In this embodiment, the first light-emitting chip 120 and the second light-emitting chip 130 share the same cathode 160B. Please refer to FIG2. FIG2 is a circuit diagram of the first light-emitting chip and the second light-emitting chip according to an embodiment of the present invention. As mentioned above, the light-emitting device 100 can control the light-emitting state of the first light-emitting layer 124 of the first light-emitting device 120 by means of the first anode 160A and the cathode 160B, and control the light-emitting state of the second light-emitting layer 134 of the second light-emitting device 130 by means of the second anode 160C and the cathode 160B. Since the first light-emitting device 120 and the second light-emitting device 130 share a cathode, the number of electrodes required to operate the first light-emitting device 120 and the second light-emitting device 130 can be reduced.

[0023] Please return to Figure 1. As shown in Figure 1, the second surface 122B of the first substrate 122 is opposite to the fourth surface 132B of the second substrate 132. Therefore, the first light-emitting chip 120 and the second light-emitting chip 130 are arranged back-to-back. The first light-emitting layer 124 of the first light-emitting chip 120 does not contact the second substrate 132 of the second light-emitting chip 130, and the second light-emitting layer 134 of the second light-emitting chip 130 does not contact the first substrate 122 of the first light-emitting chip 120. This back-to-back arrangement avoids damage to the first light-emitting layer 124 and the second light-emitting layer 134 caused by direct contact with the second substrate 132 and the first substrate 122, such as peeling off from the first substrate 122 or the second substrate 132.

[0024] As shown in Figure 1, the light-emitting device 100 further includes a die-bonding layer 140 located between the first light-emitting chip 120 and the second light-emitting chip 130. In some embodiments, the die-bonding layer 140 is made of a transparent material to avoid absorbing the first color light L1 emitted by the first light-emitting device 120. In some embodiments, the die-bonding layer 140 is made of an electrically insulating material to prevent the first light-emitting device 120 and the second light-emitting device 130 from forming an electrical connection through the die-bonding layer 140. In some embodiments, the material of the die-bonding layer 140 may be a silicone-based adhesive or an epoxy-based adhesive, or a material with similar functions; this disclosure is not limited thereto.

[0025] Figure 3 is a schematic diagram of a light-emitting device according to an embodiment of the present invention. Please refer to Figure 3. The light-emitting device 100 shown in Figure 3 is similar to the light-emitting device 100 shown in Figure 1, except that in Figure 3, it further includes an encapsulation body 170 to cover the substrate 110, the first light-emitting chip 120, and the second light-emitting chip 130, and to protect the conductive wire 138. In some embodiments, the encapsulation body 170 is a transparent material including molding compounds, polymeric materials, such as silicone-based or epoxy-based adhesives, combinations thereof, or other suitable materials.

[0026] In some embodiments, if the light-emitting device 100 needs to emit white light, the encapsulation 170 further includes phosphor. After being irradiated by a first color light L1 and a second color light L2, the phosphor emits a third color light L3 that is different from the first color light L1 and the second color light L2. In some embodiments, the third color light L3 is red light with a wavelength range of 590 nm to 660 nm. In some embodiments, the phosphor is a red phosphor A2BF6:Mn4+, where A can be K, Na, or Ba, and B can be Si, Ti, Zr, or Al, for example, K2SiF6:Mn4+ (KSF).

[0027] Therefore, by means of the light-emitting device 100 shown in Figure 3, the light-emitting device can simultaneously emit green and blue light of the first color light and the second color light, as well as red light of the third color light, and emit white light.

[0028] Figures 4 to 9 are flowcharts illustrating the fabrication process of a light-emitting device according to an embodiment of the present invention.

[0029] Please refer to Figure 4. A substrate 110 is provided. The substrate 110 has surfaces 110A and 110B that are opposite to each other.

[0030] Please refer to Figure 5. The first light-emitting chip 120 is electrically connected to the substrate 110 via a flip-chip method. The first light-emitting chip 120 includes a first substrate 122 and a first light-emitting layer 124. A eutectic layer 126 is located between the substrate 110 and the first light-emitting chip 120. Therefore, the first light-emitting chip 120 can be electrically connected to the substrate 110 via the eutectic layer 126. Please refer to Figure 5, a bonding pad 150 is formed on the surface 110A of the substrate 110, and the bonding pad 150 is electrically connected to the substrate 110.

[0031] Please refer to Figure 6. A die-bonding layer 140 is formed on the second surface 122B of the first substrate 122 of the first light-emitting chip 120. In some embodiments, the die-bonding layer 140 is an electrically insulating material. The material of the die-bonding layer 140 may be a silicone-based adhesive or an epoxy-based adhesive, or a material with similar functions. This disclosure is not limited thereto.

[0032] Please refer to Figure 7. The second light-emitting chip 130 is disposed on the die-bonding layer 140 in a forward-mounted manner. The second light-emitting chip 130 includes a second substrate 132 and a second light-emitting layer 134. The fourth surface 132B of the second substrate 132 of the second light-emitting chip 130 is in contact with the die-bonding layer 140. An electrode 136 is formed on the second light-emitting layer 134 of the second light-emitting chip 130.

[0033] Please refer to Figure 8. Electrode 136 is electrically connected to pad 150 by wire bonding 138.

[0034] Please refer to Figure 9. An encapsulation 170 is formed on the substrate 110 to cover the substrate 110, the first light-emitting chip 120, and the second light-emitting chip 130, and to protect the conductive wire 138. In some embodiments, the encapsulation 170 is a transparent material including molding compounds, polymeric materials, such as silicone-based or epoxy-based adhesives, combinations thereof, or other suitable materials.

[0035] A first anode 160A, a cathode 160B, and a second anode 160C are formed on the surface 110B of the substrate 110 and are electrically connected to the substrate 110. The first light-emitting chip 120 can be electrically connected to the first anode 160A and the cathode 160B via a eutectic layer 126 and the substrate 110, respectively. Therefore, the light-emitting state of the first light-emitting layer 124 of the first light-emitting device 120 can be controlled by the first anode 160A and the cathode 160B. Furthermore, the second light-emitting layer 134 can be electrically connected to the second anode 160C via one electrode 136, one wire 138, one pad 150, and through the substrate 110, and electrically connected to the cathode 160B via the other electrode 136, the other wire 138, the other pad 150, and through the substrate 110. Therefore, the light-emitting state of the second light-emitting layer 134 of the second light-emitting device 130 can be controlled by the second anode 160C and the cathode 160B.

[0036] In summary, by attaching the first light-emitting chip to the substrate in a flip-chip manner, and attaching the second light-emitting chip located on the first light-emitting chip to the substrate in a top-mount manner, the color halo phenomenon between different colors of light can be effectively improved.

[0037] 100: Light-emitting device 110:Substrate 110A, 110B: Surface 120: First light-emitting chip 122: First substrate 122A: First surface 122B: Second Surface 124: First luminescent layer 126: Co-gold layer 130: Second light-emitting chip 132: Second substrate 132A: Third Surface 132B: Fourth Surface 134: Second luminescent layer 136: Electrode 138: Conductor 140: Die-bonding layer 150: solder pad 160A: First anode 160B: Cathode 160C: Second anode 170: Encapsulation L1: First color light L2: Second color light L3: Third color light

Claims

1. A light-emitting device, comprising: One substrate; A first light-emitting chip, disposed on the substrate, for emitting a first color of light, the first light-emitting chip including a first substrate and a first light-emitting layer, the first substrate including a first surface and a second surface opposite to the first surface, the first light-emitting layer being located on the first surface; a second light-emitting chip, disposed on the first light-emitting chip, for emitting a second color of light different from the first color of light, the second light-emitting chip including a second substrate and a second light-emitting layer, the second substrate including a third surface and a fourth surface opposite to the third surface, the second light-emitting layer being located on the third surface; wherein the second surface is opposite to the fourth surface, wherein the first light-emitting chip and the second light-emitting chip simultaneously emit the first color of light and the second color of light, wherein the first color of light is green light and the second color of light is blue light, or the first color of light is blue light and the second color of light is green light, wherein the first light-emitting chip and the second light-emitting chip have the same cathode, and the same cathode is located on the substrate, wherein the first light-emitting chip is electrically connected to the substrate by flip-chip mounting, and the second light-emitting chip is electrically connected to the substrate by upright mounting.

2. The light-emitting device as claimed in claim 1, wherein the orthographic projection of the fourth surface in the vertical direction lies within the second surface.

3. The light-emitting device as claimed in claim 1, wherein the area of ​​the second surface is larger than that of the fourth surface.

4. The light-emitting device as claimed in claim 1, wherein the area of ​​the fourth surface is 25% to 80% of the area of ​​the second surface.

5. The light-emitting device as claimed in claim 1, further comprising: A co-gold layer is located between the substrate and the first light-emitting wafer; and a first anode, located on the substrate; And wherein the first light-emitting wafer is electrically connected to the first anode and the common cathode respectively via the co-gold layer.

6. The light-emitting device as described in claim 5, further comprising: Multiple solder pads, wherein the multiple solder pads are located on the substrate; And a second anode, located on the substrate, wherein the second light-emitting layer is electrically connected to the second anode via a first wire of a plurality of wires through a first pad of a plurality of pads, wherein the second light-emitting layer is electrically connected to the common cathode via a second wire of the plurality of wires through a second pad of a plurality of pads.

7. The light-emitting device as claimed in claim 1, further comprising: A die-bonding layer is located between the first light-emitting wafer and the second light-emitting wafer, wherein the die-bonding layer is transparent and electrically insulating.

8. The light-emitting device as claimed in claim 1, wherein the first substrate is transparent to the first color light and the second substrate is transparent to the first color light.

9. The light-emitting device as claimed in claim 1, wherein the wavelength range of the blue light is 430-480 nm and the wavelength range of the green light is 500-560 nm.

10. The light-emitting device as claimed in claim 1, further comprising: An encapsulation body is used to cover the substrate, the first light-emitting chip, and the second light-emitting chip, wherein the encapsulation body includes phosphor, and the phosphor emits a third color light different from the first color light and the second color light after being irradiated by the first color light and the second color light.

11. The light-emitting device as claimed in claim 10, wherein the third color light is red light.

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