TWI895112B - Light emitting device structure and operation method thereof - Google Patents

Abstract

A light emitting device structure including a first light emitting element and a second light emitting element is provided. The first light emitting element includes a first anode and a first cathode. The second light emitting element is stacked on the first light emitting element and includes a second anode and a second cathode, wherein the second cathode is electrically connected to the first anode. An operation method of the light emitting device structure is also provided.

Description

Light emitting device structure and operating method thereof

The present invention relates to a light emitting device structure and an operating method thereof.

In traditional LED display panels, multi-colored LEDs are placed on a single plane alongside circuitry (including driver components and wiring) to achieve full-color display. However, as resolution increases, the LEDs are increasingly close together, making the circuitry too crowded and difficult to manufacture. Furthermore, placing multi-colored LEDs on the same plane consumes a large area, making it difficult to increase resolution.

The present invention provides a light emitting device structure and an operating method thereof, which are helpful to improve resolution or reduce manufacturing difficulty.

In one embodiment of the present invention, a light-emitting device structure includes a first light-emitting element and a second light-emitting element. The first light-emitting element includes a first anode and a first cathode. The second light-emitting element is stacked on the first light-emitting element and includes a second anode and a second cathode, wherein the second cathode is electrically connected to the first anode.

In another embodiment of the present invention, a method for operating a light-emitting device structure includes the following steps. A light-emitting device structure is provided, the light-emitting device structure comprising a first light-emitting element and a second light-emitting element; the first light-emitting element comprises a first anode and a first cathode; and the second light-emitting element is stacked on the first light-emitting element and comprises a second anode and a second cathode, wherein the second cathode is electrically connected to the first anode. A voltage difference between the first anode and the first cathode is set to be greater than a first value, so that the first light-emitting element emits a first color of light. A voltage difference between the second anode and the second cathode is set to be greater than a second value, so that the second light-emitting element emits a second color of light, wherein the second color of light is different from the first color of light.

In order to make the above features and advantages of the present invention more clearly understood, embodiments are given below and described in detail with reference to the accompanying drawings.

The directional terms mentioned herein, such as "up", "down", "front", "back", "left", "right", etc., are only used with reference to the directions in the accompanying drawings. Therefore, the directional terms used are used for illustration and are not used to limit the present invention.

In the accompanying drawings, each diagram depicts the general characteristics of methods, structures, or materials used in specific embodiments. However, these diagrams should not be interpreted as defining or limiting the scope or nature of these embodiments. For example, the relative size, thickness, and position of various layers, regions, or structures may be reduced or exaggerated for clarity.

In the following embodiments, the same or similar elements will be denoted by the same or similar reference numerals, and their detailed description will be omitted. In addition, features in different embodiments may be combined with each other without conflict, and simple equivalent changes and modifications made according to this specification or the scope of the patent application are still within the scope of this patent.

The terms "first," "second," and the like mentioned in this specification or patent application are used only to name different components or to distinguish different embodiments or scopes, and are not intended to limit the upper or lower limit on the number of components, nor to define the manufacturing order or placement order of the components. Furthermore, "one component/film layer disposed on (or over) another component/film layer" may encompass situations where the component/film layer is directly disposed on (or over) the other component/film layer, with the two components/film layers in direct contact; and situations where the component/film layer is indirectly disposed on (or over) the other component/film layer, with one or more components/film layers interposed between the two components/film layers.

Figures 1 to 5, 7, 8, and 10 are schematic diagrams of light-emitting device structures according to various embodiments of the present disclosure. Figure 6 is a schematic top view of the light-emitting device structure of Figure 5. Figure 9 is a schematic top view of the light-emitting device structure of Figure 8.

1 , the light emitting device structure 1 may include a first light emitting element 10 and a second light emitting element 12 stacked on the first light emitting element 10, but is not limited thereto. The light emitting device structure 1 may further include other elements and/or layers according to different requirements.

Taking a full-color light-emitting device structure as an example, the first light-emitting element 10 can be a single-color light-emitting element, and the second light-emitting element 12 can be a dual-color light-emitting element, but this is not limiting. In other embodiments, the first light-emitting element 10 can be a dual-color light-emitting element, and the second light-emitting element 12 can be a single-color light-emitting element. The single-color light-emitting element can be a red light-emitting element, a green light-emitting element, or a blue light-emitting element. Correspondingly, the dual-color light-emitting element can be a green-blue light-emitting element, a blue-red light-emitting element, or a red-green light-emitting element. For ease of explanation, the following description assumes that the single-color light-emitting element is a red light-emitting element and the dual-color light-emitting element is a green-blue light-emitting element.

The first light-emitting element 10 may include a first anode 100 and a first cathode 102. The first anode 100 and the first cathode 102 are made of a conductive material. The conductive material may include a transparent conductive material (such as a metal oxide or graphene) or a non-transparent conductive material (such as a metal or alloy). The top-view shapes of the first anode 100 and the first cathode 102 are not limited. For example, the top-view shapes of the first anode 100 and the first cathode 102 may each be a block, a strip, a sheet, a frame, a ring, or an irregular shape. Furthermore, the first anode 100 and the first cathode 102 may have the same or different top-view shapes.

Depending on different needs, the first light-emitting element 10 may further include other elements and/or layers. For example, the first light-emitting element 10 may further include a first semiconductor material layer 104, with the first anode 100 and the first cathode 102 disposed on the first semiconductor material layer 104. In some embodiments, the first light-emitting element 10 is a vertical light-emitting diode. As shown in FIG1 , the first anode 100 and the first cathode 102 may be disposed on opposite sides of the first semiconductor material layer 104, respectively. However, the relative arrangement of the first anode 100, the first cathode 102, and the first semiconductor material layer 104 is not limited to this.

The material of the first semiconductor material layer 104 may include, but is not limited to, a gallium nitride (GaN)-based material or a gallium arsenide (GaAs)-based material. In some embodiments, the first semiconductor material layer 104 may include a light-emitting layer to emit a first color light L1. For example, if the first light-emitting element 10 is a red light-emitting element and the first color light L1 is red, the light-emitting layer may include a Group III-V material, such as, but not limited to, gallium phosphide (GaP), aluminum gallium arsenide (AlGaAs), gallium arsenide phosphide (GaAsP), or aluminum gallium indium phosphide (AlGaInP). In some embodiments, the light-emitting layer may be a multiple quantum well (MQW) layer, such as a stack of multiple layers of indium nitride (InN) layers and multiple layers of gallium nitride (GaN) layers alternately stacked, but not limited thereto.

In some embodiments, although not shown, the first semiconductor material layer 104 may further include one or more of an N-type doped layer, a P-type doped layer, an electron blocking layer, a barrier layer, a compliance layer, and other functional layers. It should be understood that the structure of the first semiconductor material layer 104 can adopt the structure of semiconductor material layers in conventional vertical red light-emitting diodes, without further limitation. Furthermore, the substrate on which the first semiconductor material layer 104 is grown may include any suitable substrate, without further limitation.

The extent to which the first semiconductor material layer 104 is covered by the first anode 100 or the first cathode 102 depends on the electrode's light transmittance or the intended application (e.g., single-sided or dual-sided light emission). If the electrode located on the light-emitting side of the first semiconductor material layer 104 is made of a non-transparent conductive material, this electrode can partially expose the first semiconductor material layer 104 to reduce shielding of the first color light L1. Figure 1 schematically illustrates an embodiment of single-sided light emission, in which the first anode 100 is located on the light-emitting side of the first semiconductor material layer 104. If the first anode 100 is made of a non-transparent conductive material, the first anode 100 can expose a portion of the first semiconductor material layer 104, that is, the first anode 100 only covers a portion of the first semiconductor material layer 104, thereby reducing the shielding of the first color light L1. On the other hand, when the first anode 100 is made of a transparent conductive material, the first anode 100 can completely or partially cover the first semiconductor material layer 104. On the other hand, the transmittance or coverage range of the first cathode 102 located on the non-light-exiting side of the first semiconductor material layer 104 is not particularly restricted.

The second light-emitting element 12 is disposed on the light-emitting side of the first light-emitting element 10 and is adapted to allow the first color light L1 to pass therethrough. The second light-emitting element 12 may include a second anode 120 and a second cathode 122, wherein the second cathode 122 is electrically connected to the first anode 100. For example, the second cathode 122 and the first anode 100 may be directly bonded together, such as by fusion bonding, but this is not limited to this embodiment.

The second anode 120 and the second cathode 122 are made of a conductive material. The conductive material may include a transparent conductive material (such as a metal oxide or graphene) or a non-transparent conductive material (such as a metal or alloy). The top-view shapes of the second anode 120 and the second cathode 122 are not limited. For example, the top-view shapes of the second anode 120 and the second cathode 122 may each be a block, a strip, a sheet, a frame, a ring, or an irregular shape. Furthermore, the second anode 120 and the second cathode 122 may have the same or different top-view shapes.

Depending on different needs, the second light-emitting element 12 may further include other elements and/or layers. For example, the second light-emitting element 12 may further include a second semiconductor material layer 124, with the second anode 120 and the second cathode 122 disposed on the second semiconductor material layer 124. In some embodiments, the second light-emitting element 12 is a vertical light-emitting diode. As shown in FIG1 , the second anode 120 and the second cathode 122 may be disposed on opposite sides of the second semiconductor material layer 124, respectively. However, the relative arrangement of the second anode 120, the second cathode 122, and the second semiconductor material layer 124 is not limited to this.

The second semiconductor material layer 124 may include two luminescent layers, each emitting a second color light L2 and a third color light L3, respectively. For example, if the second luminescent element 12 is a green-blue luminescent element, the second color light L2 is green, and the third color light L3 is blue, the materials of the two luminescent layers may include, but are not limited to, Group III-V materials such as gallium phosphide (GaP), silicon carbide (SiC), cadmium zinc selenide (ZnCdSe), or gallium nitride. In some embodiments, the two light-emitting layers may be multiple quantum well layers, wherein the green light-emitting layer may be, for example, but not limited to, a stack of multiple layers of indium gallium nitride (e.g., In _0.25 Ga _0.75 N) and multiple layers of gallium nitride (GaN) alternatingly stacked layers; and the blue light-emitting layer may be, for example, but not limited to, a stack of multiple layers of indium gallium nitride (e.g., In _0.15 Ga _0.85 N) and multiple layers of gallium nitride (GaN) alternatingly stacked layers.

In some embodiments, although not shown, the second semiconductor material layer 124 may further include one or more of an N-type doped layer, a P-type doped layer, an electron blocking layer, a barrier layer, a compliant layer, and other functional layers. It should be understood that the structure of the second semiconductor material layer 124 can adopt the structure of semiconductor material layers in conventional vertical green- and blue-emitting diodes, without limitation. Furthermore, the substrate on which the second semiconductor material layer 124 is grown may include any suitable substrate, without limitation.

The extent to which the second semiconductor material layer 124 is covered by the second anode 120 or the second cathode 122 depends on the electrode's light transmittance or the intended application (e.g., single-sided or dual-sided light emission). In this embodiment, the second light-emitting element 12 is disposed on the light-emitting side of the first light-emitting element 10. If the second cathode 122 is made of a non-transparent conductive material, the second cathode 122 can partially expose the second semiconductor material layer 124, that is, only partially cover the second semiconductor material layer 124, thereby reducing shielding of the first color light L1. Furthermore, the second anode 120 can be exposed to a portion of the second semiconductor material layer 124, that is, the second anode 120 can cover only a portion of the second semiconductor material layer 124, thereby reducing shielding of the first color light L1, the second color light L2, and/or the third color light L3. On the other hand, when the second anode 120 and the second cathode 122 are made of a transparent conductive material, the second anode 120 and the second cathode 122 can completely or partially cover the second semiconductor material layer 124. Furthermore, when the second cathode 122 and the first anode 100 are fixed together using direct bonding, the second cathode 122 and the first anode 100 can have the same top-view shape and area.

The operating method of the light-emitting device structure 1 may include the following steps: providing the light-emitting device structure 1; making the voltage difference between the first anode 100 and the first cathode 102 (e.g., voltage V2 minus voltage V1) greater than a first value, so that the first light-emitting element 10 emits a first color light L1; and making the voltage difference between the second anode 120 and the second cathode 122 (e.g., voltage V3 minus voltage V2) greater than a second value, so that the second light-emitting element 12 emits a second color light L2, wherein the second color light L2 is a different color from the first color light L1.

In embodiments where the first light-emitting element 10 is a monochromatic light-emitting element and the second light-emitting element 12 is a bichromatic light-emitting element, the operating method of the light-emitting device structure 1 may further include causing the voltage difference between the second anode 120 and the second cathode 122 (e.g., voltage V3 minus voltage V2) to be greater than a third value, so that the second light-emitting element 12 emits a third color light L3. The third value is different from the second value, and the third color light L3, the second color light L2, and the first color light L1 are different colors. For example, in embodiments where the first light-emitting element 10 is a red light-emitting element 10 and the second light-emitting element 12 is a green-blue light-emitting element, the first color light L1 is red, the second color light L2 is green, and the third color light L3 is blue.

Each of the first to third values may vary depending on factors such as the selected materials and process parameters. For example, in an embodiment where the first semiconductor material layer 104 is made of a gallium arsenide-based material, the first value is, for example, 2 volts (V). That is, when the voltage difference between the first anode 100 and the first cathode 102 is greater than 2 volts, the first light-emitting element 10 emits the first color light L1. On the other hand, in an embodiment where the first semiconductor material layer 104 is made of a gallium nitride-based material, the first value is, for example, 3 volts. That is, when the voltage difference between the first anode 100 and the first cathode 102 is greater than 3 volts, the first light-emitting element 10 emits the first color light L1. Furthermore, the second value is, for example, 3 volts, and the third value is, for example, 4 volts. That is, when the voltage difference between the second anode 120 and the second cathode 122 is greater than 3 volts, the second light-emitting element 12 emits the second color light L2, and when the voltage difference between the second anode 120 and the second cathode 122 is greater than 4 volts, the second light-emitting element 12 emits the third color light L3. It should be understood that the above-mentioned first to third values are merely examples and are not intended to limit the present invention.

In some embodiments, the second cathode 122 and the first anode 100 can be grounded (i.e., the voltage V2 is 0). Under this architecture, the voltage V1 can be set to -2 volts or -3 volts to illuminate the first light-emitting element 10 (causing the first light-emitting element 10 to emit the first color light L1), and the voltage V3 can be set to 3 volts or 4 volts to illuminate the second light-emitting element 12 (causing the second light-emitting element 12 to emit the second color light L2 or the third color light L3).

In other embodiments, the first cathode 102 may be grounded (ie, the voltage V1 is 0). In this configuration, the voltage V2 may be set to 2V or 3V to illuminate the first light-emitting element 10 (eg, to cause the first light-emitting element 10 to emit the first color light L1).

Compared to integrating three color luminescent layers into a single LED, independently forming the first and second light-emitting elements 10 and 12 and then stacking them together to form the light-emitting device structure 1 helps improve the brightness of colored light (such as red light), reduce process complexity, and increase yield. Furthermore, compared to placing multiple color LEDs on the same plane, the vertically stacked light-emitting device structure 1 occupies a smaller area, thereby improving resolution. Furthermore, electrically connecting the second cathode 122 of the second light-emitting element 12 to the first anode 100 of the first light-emitting element 10 helps reduce the number of pins of the light-emitting device structure 1 and the corresponding number of external wires, thereby improving circuit layout flexibility, simplifying the manufacturing process, reducing circuit space, or improving resolution.

2 , the main differences between the light emitting device structure 1A and the light emitting device structure 1 of FIG1 are described below. In the light emitting device structure 1A, the single-color light emitting element (eg, the first light emitting element 10 ) is, for example, a combination of a blue light emitting element and a red wavelength conversion layer 106 .

Specifically, the first light-emitting element 10A includes a first anode 100, a first cathode 102, a first semiconductor material layer 104A, and a red wavelength conversion layer 106. The blue light-emitting element is primarily composed of the first anode 100, the first cathode 102, and the first semiconductor material layer 104A. The first semiconductor material layer 104A includes a blue light-emitting layer to output blue light B.

Blue light B is converted into first color light L1 by the red wavelength conversion layer 106. The first semiconductor material layer 104A can employ the structure of semiconductor material layers in conventional vertical blue light-emitting diodes, without limitation. The material of the red wavelength conversion layer 106 may include red quantum dots, red phosphors, rare earth materials, or other red materials. Furthermore, the red wavelength conversion layer 106 may be in the form of particles, a gel, a film, or a sheet.

In a configuration where the first light-emitting element 10A is a combination of a blue light-emitting element and a red wavelength conversion layer, and the second light-emitting element 12 is a green-blue light-emitting element, the first and third values can be the same (e.g., both 4 volts). Specifically, the voltage difference between the first anode 100 and the first cathode 102 (e.g., voltage V2 minus voltage V1) can be greater than 4 volts, causing the first semiconductor material layer 104A to emit blue light B. This blue light B is then converted by the red wavelength conversion layer 106 into first color light L1 and output from the first light-emitting element 10A. In a configuration where the second cathode 122 and the first anode 100 are grounded, voltage V1 is, for example, -4 volts. In a configuration where the first cathode 102 is grounded, voltage V2 is, for example, 4 volts.

In some embodiments, although not shown in FIG. 2 , the first light emitting element 10A may be a green or blue light emitting element, and may emit blue light B by voltage modulation, and then be converted into the first color light L1 by the red wavelength conversion layer 106 .

Referring to FIG3 , the primary differences between the light-emitting device structure 1B and the light-emitting device structure 1 of FIG1 are described below. Light-emitting device structure 1B further includes a third light-emitting element 14. The third light-emitting element 14 is stacked on the second light-emitting element 12 and is adapted to allow the first color light L1 and the second color light L2 to pass therethrough. The third light-emitting element 14 includes a third anode 140 and a third cathode 142, wherein the third cathode 142 is electrically connected to the second anode 120. For example, in a vertical light-emitting diode configuration, the third cathode 142 and the second anode 120 may be fused together by melt bonding, but this is not a limitation.

The first light-emitting element 10, the second light-emitting element 12B, and the third light-emitting element 14 can all be single-color light-emitting elements. For example, the first light-emitting element 10 is a red light-emitting element, the second light-emitting element 12B is a green light-emitting element, and the third light-emitting element 14 is a blue light-emitting element, but this is not limiting. The first semiconductor material layer 104 in the first light-emitting element 10 comprises a red light-emitting layer to output red light (first color light L1), the second semiconductor material layer 124B in the second light-emitting element 12B comprises a green light-emitting layer to output green light (second color light L2), and the third semiconductor material layer 144 in the third light-emitting element 14 comprises a blue light-emitting layer to output blue light (third color light L3).

In some embodiments, although not shown, the first semiconductor material layer 104, the second semiconductor material layer 124B, and the third semiconductor material layer 144 may each further include one or more of an N-type doped layer, a P-type doped layer, an electron blocking layer, a barrier layer, a compliant layer, and other functional layers. It should be understood that the structures of the first semiconductor material layer 104, the second semiconductor material layer 124B, and the third semiconductor material layer 144 may respectively adopt the structures of semiconductor material layers in conventional vertical red light-emitting diodes, vertical green light-emitting diodes, and vertical blue light-emitting diodes, without limitation herein. Furthermore, the substrate on which the first semiconductor material layer 104, the second semiconductor material layer 124B, and the third semiconductor material layer 144 are grown may include any suitable substrate and is not particularly limited.

By independently forming three color LEDs and then stacking the three color LEDs together, the voltage difference (e.g., voltage V2 minus voltage V1) between the first anode 100 and the first cathode 102 can be greater than a first value (e.g., 2 volts or 3 volts), so that the first light emitting element 10 emits the first color light L1; the second anode 120 and the second cathode 12 2 (e.g., voltage V3 minus voltage V2) is greater than a second value (e.g., 3 volts) to cause the second light-emitting element 12B to emit the second color light L2; and the voltage difference between the third anode 140 and the third cathode 142 (e.g., voltage V4 minus voltage V3) is greater than a third value (e.g., 4 volts) to cause the third light-emitting element 14 to emit the third color light L3. The first value and the third value may be different, and the second value and the third value may be different, but are not limited thereto.

Compared to integrating three color emitting layers into a single LED, independently forming different color emitting elements (such as the first light-emitting element 10, the second light-emitting element 12B, and the third light-emitting element 14) and then stacking them together to form the light-emitting device structure 1B can help improve the brightness of each color, reduce process complexity, and increase yield. Furthermore, compared to placing multiple color LEDs on the same plane, the vertically stacked light-emitting device structure 1B occupies a smaller area, thereby improving resolution. Furthermore, by connecting light-emitting elements of different colors in series, the number of pins of the light-emitting device structure 1B and the corresponding number of external wires can be reduced, thereby improving circuit layout flexibility, simplifying the manufacturing process, reducing circuit space, or improving resolution.

Referring to FIG4 , the main differences between light-emitting device structure 1C and light-emitting device structure 1B in FIG3 are described below. In light-emitting device structure 1C, first light-emitting element 10A is a combination of a blue light-emitting element and a red wavelength conversion layer, and second light-emitting element 12C is a combination of a blue light-emitting element and a green wavelength conversion layer.

Specifically, the first light-emitting element 10A includes a first anode 100, a first cathode 102, a first semiconductor material layer 104A, and a red wavelength conversion layer 106. The blue light-emitting element primarily comprises the first anode 100, the first cathode 102, and the first semiconductor material layer 104A. The first semiconductor material layer 104A includes a blue light-emitting layer to output blue light B. The blue light B is converted into the first color light L1 by the red wavelength conversion layer 106.

The second light-emitting element 12C includes a second anode 120, a second cathode 122, a second semiconductor material layer 124C, and a green wavelength conversion layer 126. The blue light-emitting element primarily comprises the second anode 120, the second cathode 122, and the second semiconductor material layer 124C. The second semiconductor material layer 124C includes a blue light-emitting layer to output blue light B. The blue light B is converted into second color light L2 by the green wavelength conversion layer 126. The first semiconductor material layer 104A and the second semiconductor material layer 124C can employ the structure of semiconductor material layers in conventional vertical blue light-emitting diodes, without further limitation.

The red wavelength conversion layer 106 may be made of red quantum dots, red phosphors, rare earth materials, or other red materials. Furthermore, the red wavelength conversion layer 106 may be in the form of particles, a gel, a film, or a sheet. The green wavelength conversion layer 126 may be made of green quantum dots, green phosphors, rare earth materials, or other green materials. Furthermore, the green wavelength conversion layer 126 may be in the form of particles, a gel, a film, or a sheet.

In a configuration where the first light-emitting element 10A is a combination of a blue light-emitting element and a red wavelength conversion layer, the second light-emitting element 12C is a combination of a blue light-emitting element and a green wavelength conversion layer, and the third light-emitting element 14 is a blue light-emitting element, the first, second, and third values can be the same (e.g., 4 volts). Specifically, the voltage difference between the first anode 100 and the first cathode 102 (e.g., voltage V2 minus voltage V1) can be greater than 4 volts, causing the first semiconductor material layer 104A to emit blue light B. The blue light B is then converted by the red wavelength conversion layer 106 into first color light L1, which is then output from the first light-emitting element 10A. The voltage difference between the second anode 120 and the second cathode 122 (e.g., voltage V3 minus voltage V2) can be set to greater than 4 volts, causing the second semiconductor material layer 124C to emit blue light B. This blue light B is converted by the green wavelength conversion layer 126 into second color light L2 and output from the second light-emitting element 12C. The voltage difference between the third anode 140 and the third cathode 142 (e.g., voltage V4 minus voltage V3) can be set to greater than 4 volts, causing the third semiconductor material layer 144 to emit third color light L3.

Referring to FIG. 5 , the primary difference between the light-emitting device structure 1D and the light-emitting device structure 1 of FIG. 1 is that the first light-emitting element 10D and the second light-emitting element 12D in the light-emitting device structure 1D are both lateral light-emitting diodes, wherein the first anode 100 and the first cathode 102 are disposed on the same side (e.g., the light-emitting side) of the first semiconductor material layer 104D, and the second anode 120 and the second cathode 122 are disposed on the same side (e.g., the light-emitting side) of the second semiconductor material layer 124D.

The first semiconductor material layer 104D may include a terrace 104-1 and a protrusion 104-2. Although not shown in FIG. 5 , the terrace 104-1 may include, but is not limited to, a substrate, a buffer layer, and an N-type doped layer. The buffer layer and the N-type doped layer are sequentially stacked on the substrate. The protrusion 104-2 and the first cathode 102 are disposed on the N-type doped layer of the terrace 104-1 and are separated from each other. The protrusion 104-2 may include, but is not limited to, a compliant layer, a light-emitting layer (e.g., a red light-emitting layer), an electron blocking layer, and a P-type doped layer sequentially stacked on the terrace 104-1. The first anode 100 is disposed on the protruding portion 104-2.

The second semiconductor material layer 124D may include a terrace portion 124-1 and a protrusion 124-2. Although not shown in FIG5 , the terrace portion 124-1 may include a substrate, a buffer layer, and an N-type doped layer, but is not limited thereto. The buffer layer and the N-type doped layer are sequentially stacked on the substrate. The protrusion 124-2 and the second cathode 122 are disposed on the N-type doped layer of the terrace portion 124-1 and are separated from each other. The protrusion 124-2 may include a compliant layer, a blue light-emitting layer (or a green light-emitting layer), a barrier layer, a green light-emitting layer (or a blue light-emitting layer), an electron blocking layer, and a P-type doped layer sequentially stacked on the platform 124-1, but is not limited thereto. The second anode 120 is disposed on the protrusion 124-2.

It should be understood that the number of film layers and/or stacking order in the first semiconductor material layer 104D or the second semiconductor material layer 124D may be changed according to actual needs and are not limited to the above examples.

In a configuration where both the first light-emitting element 10D and the second light-emitting element 12D are horizontal light-emitting diodes, the second light-emitting element 12D can be secured to the first light-emitting element 10D via a transparent adhesive layer (not shown) or other securing elements (not shown). Furthermore, the second cathode 122 and the first anode 100 can be electrically connected via wires W. FIG5 schematically illustrates the wires W used to electrically connect the second cathode 122 and the first anode 100, but the actual arrangement of the wires W can vary depending on actual needs.

FIG6 schematically illustrates one configuration of the wire W. Referring to FIG6 , in some embodiments, the top-view area of the first semiconductor material layer 104D may be larger than the top-view area of the second semiconductor material layer 124D. The wire W may be disposed on both the first semiconductor material layer 104D and the second semiconductor material layer 124D and electrically isolated from the first cathode 102 and the second anode 120.

For example, the top-view area of the terrace portion 104-1 of the first semiconductor material layer 104D may be larger than the top-view area of the protrusion 104-2 of the first semiconductor material layer 104D, the top-view area of the protrusion 104-2 of the first semiconductor material layer 104D may be larger than the top-view area of the terrace portion 124-1 of the second semiconductor material layer 124D, and the top-view area of the terrace portion 124-1 of the second semiconductor material layer 124D may be larger than the top-view area of the protrusion 124-2 of the second semiconductor material layer 124D. The wire W may be disposed on the terrace portion 124-1 of the second semiconductor material layer 124D and the protrusion 104-2 of the first semiconductor material layer 104D and electrically connect the second cathode 122 and the first anode 100.

Through the aforementioned voltage differential control (see the operating method of light-emitting device structure 1 in FIG1 ), the light-emitting region R of light-emitting device structure 1D can also achieve full-color display (e.g., outputting red, green, and/or blue light). The functionality of light-emitting device structure 1D can be referenced to that of light-emitting device structure 1 in FIG1 , and will not be repeated here.

Referring to FIG. 7 , the primary difference between the light-emitting device structure 1E and the light-emitting device structure 1A of FIG. 2 is that the first light-emitting element 10E and the second light-emitting element 12D in the light-emitting device structure 1E are both horizontal light-emitting diodes, wherein the first anode 100 and the first cathode 102 are disposed on the same side (e.g., the light-emitting side) of the first semiconductor material layer 104E, and the second anode 120 and the second cathode 122 are disposed on the same side (e.g., the light-emitting side) of the second semiconductor material layer 124D.

The primary difference between first light-emitting element 10E and first light-emitting element 10D in Figure 5 is that first light-emitting element 10E is a combination of a blue light-emitting element (including a first anode 100, a first cathode 102, and a first semiconductor material layer 104E) and a red wavelength conversion layer 106. First semiconductor material layer 104E includes a mesa 104-1 and a protrusion 104-2'. Although not shown in Figure 7, mesa 104-1 may include, but is not limited to, a substrate, a buffer layer, and an N-type doped layer. The buffer layer and N-type doped layer are sequentially stacked on the substrate. The protrusion 104-2' and the first cathode 102 are disposed on the N-type doped layer of the platform 104-1 and are separated from each other. The protrusion 104-2' may include, but is not limited to, a compliant layer, a light-emitting layer (e.g., a blue light-emitting layer), an electron blocking layer, and a P-type doped layer sequentially stacked on the platform 104-1. The first anode 100 is disposed on the protrusion 104-2'. The blue light B output by the blue light-emitting layer is converted into the first color light L1 by the red wavelength conversion layer 106 and then output from the first light-emitting element 10E.

The operation method of the light emitting device structure 1E may refer to the operation method of the light emitting device structure 1A in FIG. 2 , and will not be repeated here.

In some embodiments, although not shown in FIG. 7 , the first light-emitting element 10E may be a green-blue light-emitting element (for example, the first semiconductor material layer 104E may be replaced with the second semiconductor material layer 124D). The first light-emitting element 10E may emit blue light B by modulating the voltage difference, and the blue light B may be converted into the first color light L1 by the red wavelength conversion layer 106 .

Referring to FIG8 , the main difference between the light-emitting device structure 1F and the light-emitting device structure 1B in FIG3 is that the first light-emitting element 10D, the second light-emitting element 12F, and the third light-emitting element 14F in the light-emitting device structure 1E are all horizontal light-emitting diodes, wherein the first anode 100 and the first cathode 102 are arranged on the same side (e.g., the light-emitting side) of the first semiconductor material layer 104D, the second anode 120 and the second cathode 122 are arranged on the same side (e.g., the light-emitting side) of the second semiconductor material layer 124F, and the third anode 140 and the third cathode 142 are arranged on the same side (e.g., the light-emitting side) of the third semiconductor material layer 144F.

The second semiconductor material layer 124F may include a platform portion 124-1 and a protrusion 124-2'. Although not shown in FIG8 , the platform portion 124-1 may include a substrate, a buffer layer, and an N-type doped layer, but is not limited thereto. The buffer layer and the N-type doped layer are sequentially stacked on the substrate. The protrusion 124-2' and the second cathode 122 are disposed on the N-type doped layer of the platform portion 124-1 and are separated from each other. The protrusion 124-2' may include a compliant layer, a green light-emitting layer, an electron blocking layer, and a P-type doped layer sequentially stacked on the platform portion 124-1, but is not limited thereto. The second anode 120 is disposed on the protrusion 124-2'.

The third semiconductor material layer 144F may include a terrace 144-1 and a protrusion 144-2. Although not shown in FIG. 8 , the terrace 144-1 may include, but is not limited to, a substrate, a buffer layer, and an N-type doped layer. The buffer layer and the N-type doped layer are sequentially stacked on the substrate. The protrusion 144-2 and the third cathode 142 are disposed on the N-type doped layer of the terrace 144-1 and are separated from each other. The protrusion 144-2 may include, but is not limited to, a compliant layer, a blue light-emitting layer, an electron blocking layer, and a P-type doped layer sequentially stacked on the terrace 144-1. The third anode 140 is disposed on the protrusion 144-2.

The operation method of the light emitting device structure 1F may refer to the operation method of the light emitting device structure 1B in FIG. 3 , and will not be repeated here.

In a configuration where the first light-emitting element 10D, the second light-emitting element 12F, and the third light-emitting element 14F are all horizontal light-emitting diodes, the second light-emitting element 12F can be fixed to the first light-emitting element 10D via a transparent adhesive layer (not shown) or other fixing elements (not shown), and the third light-emitting element 14F can be fixed to the second light-emitting element 12F via a transparent adhesive layer (not shown) or other fixing elements (not shown). Furthermore, the second cathode 122 and the first anode 100 can be electrically connected via a wire W, and the third cathode 142 and the second anode 120 can be electrically connected via a wire W'. FIG8 schematically illustrates a wire W for electrically connecting the second cathode 122 to the first anode 100 and a wire W′ for electrically connecting the third cathode 142 to the second anode 120. However, the actual arrangement of the wires W and W′ may be changed according to actual needs.

FIG9 schematically illustrates one configuration of wires W and W'. Referring to FIG9 , in some embodiments, the top-view area of the first semiconductor material layer 104D may be larger than the top-view area of the second semiconductor material layer 124F, and the top-view area of the second semiconductor material layer 124F may be larger than the top-view area of the third semiconductor material layer 144F. Furthermore, wires W may be disposed on the first semiconductor material layer 104D and the second semiconductor material layer 124F and electrically isolated from the first cathode 102 and the second anode 120. The wire W' can be disposed in the second semiconductor material layer 124F and the third semiconductor material layer 144F and be electrically insulated from the second cathode 122 and the third anode 140.

For example, the top view area of the terrace portion 104-1 of the first semiconductor material layer 104D may be larger than the top view area of the protrusion 104-2 of the first semiconductor material layer 104D, the top view area of the protrusion 104-2 of the first semiconductor material layer 104D may be larger than the top view area of the terrace portion 124-1 of the second semiconductor material layer 124F, and the top view area of the terrace portion 124-1 of the second semiconductor material layer 124F may be larger than the top view area of the protrusion 104-2 of the first semiconductor material layer 104D. The top-view area may be larger than the top-view area of the protrusion 124-2' of the second semiconductor material layer 124F, the top-view area of the protrusion 124-2' of the second semiconductor material layer 124F may be larger than the top-view area of the platform portion 144-1 of the third semiconductor material layer 144F, and the top-view area of the platform portion 144-1 of the third semiconductor material layer 144F may be larger than the top-view area of the protrusion 144-2 of the third semiconductor material layer 144F. The wire W can be set on the platform portion 124-1 of the second semiconductor material layer 124F and the protrusion 104-2 of the first semiconductor material layer 104D and electrically connect the second cathode 122 with the first anode 100, and the wire W’ can be set on the platform portion 144-1 of the third semiconductor material layer 144F and the protrusion 124-2’ of the second semiconductor material layer 124F and electrically connect the third cathode 142 with the second anode 120.

Through the aforementioned voltage differential control (see the operating method of the light-emitting device structure 1B in FIG3 ), the light-emitting region R of the light-emitting device structure 1F can also perform full-color display (e.g., outputting red, green, and/or blue light). The performance of the light-emitting device structure 1F can be referenced to that of the light-emitting device structure 1B in FIG3 , and will not be repeated here.

Referring to FIG. 10 , the primary difference between light-emitting device structure 1G and light-emitting device structure 1C in FIG. 4 is that the first light-emitting element 10E, the second light-emitting element 12G, and the third light-emitting element 14F in light-emitting device structure 1G are all horizontal light-emitting diodes, wherein the first anode 100 and the first cathode 102 are disposed on the same side (e.g., the light-emitting side) of the first semiconductor material layer 104E, the second anode 120 and the second cathode 122 are disposed on the same side (e.g., the light-emitting side) of the second semiconductor material layer 124G, and the third anode 140 and the third cathode 142 are disposed on the same side (e.g., the light-emitting side) of the third semiconductor material layer 144F.

Details of the first light-emitting element 10E can be found in the description of the first light-emitting element 10E in FIG. 7 , and will not be repeated here. Furthermore, details of the third light-emitting element 14F can be found in the description of the third light-emitting element 14F in FIG. 8 , and will not be repeated here. The main difference between the second light-emitting element 12G and the second light-emitting element 12F in FIG. 8 is that the second light-emitting element 12G is a combination of a blue light-emitting element (including a second anode 120 , a second cathode 122 , and a second semiconductor material layer 124G) and a green wavelength conversion layer 126 .

The second semiconductor material layer 124G may include a platform portion 124-1 and a protrusion 124-2''. Although not shown in Figure 10, the platform portion 124-1 may include a substrate, a buffer layer, and an N-type doped layer, but is not limited to this. The buffer layer and the N-type doped layer are stacked in sequence on the substrate. The protrusion 124-2'' and the second cathode 122 are arranged on the N-type doped layer of the platform portion 124-1 and are separated from each other. The protrusion 124-2'' may include a compliant layer, a blue light-emitting layer, an electron blocking layer, and a P-type doped layer stacked in sequence on the platform portion 124-1, but is not limited to this. The second anode 120 is disposed on the protrusion 124-2''. The blue light B emitted by the blue light emitting layer is converted into the second color light L2 by the green wavelength conversion layer 126.

The operation method of the light emitting device structure 1G may refer to the operation method of the light emitting device structure 1C in FIG. 4 , and will not be repeated here.

In summary, in embodiments of the present invention, independently forming different-color light-emitting elements and then stacking them together to form a light-emitting device structure helps improve the brightness of each color, reduce manufacturing complexity, and increase yield. Furthermore, the vertically stacked light-emitting device structure occupies a smaller area, thereby improving resolution. Furthermore, by connecting different-color light-emitting elements in series, the number of pins and corresponding external wiring in the light-emitting device structure is reduced, thereby increasing circuit layout flexibility, simplifying the manufacturing process, reducing circuit space, and improving resolution.

Although the present invention has been disclosed above by way of embodiments, they are not intended to limit the present invention. Any person having ordinary skill in the art may make slight modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the attached patent application.

1, 1A, 1C, 1D, 1E, 1F, 1G: Light-emitting device structure 10, 10A, 10D, 10E: First light-emitting element 12, 12B, 12C, 12D, 12F, 12G: Second light-emitting element 14, 14F: Third light-emitting element 100: First anode 102: First cathode 104, 104A, 104D, 104E: First semiconductor material layer 104-1, 124-1, 144-1: Mesa 104-2, 104-2', 124-2, 124-2', 124-2'', 144-2: Raised portion 106: Red wavelength conversion layer 120: Second anode 122: Second cathode 124, 124B, 124C, 124D, 124F, 124G: Second semiconductor material layer 126: Green wavelength conversion layer 140: Third anode 142: Third cathode 144, 144F: Third semiconductor material layer B: Blue light L1: First color light L2: Second color light L3: Third color light R: Luminescent region V1, V2, V3, V4: Voltages W, W': Conductors

Figures 1 to 5, 7, 8, and 10 are schematic diagrams of light-emitting device structures according to various embodiments of the present disclosure. Figure 6 is a schematic top view of the light-emitting device structure of Figure 5. Figure 9 is a schematic top view of the light-emitting device structure of Figure 8.

1: Light-emitting device structure

10: First light-emitting element

12: Second light-emitting element

100: First Anode

102: First Cathode

104: First semiconductor material layer

120: Second Anode

122: Second cathode

124: Second semiconductor material layer

L1: First color light

L2: Second color light

L3: Third color light

V1, V2, V3: Voltage

Claims (8)

A light-emitting device structure includes: a first light-emitting element including a first anode and a first cathode; a second light-emitting element stacked on the first light-emitting element and including a second anode and a second cathode, wherein the second cathode is electrically connected to the first anode; and a third light-emitting element stacked on the second light-emitting element and including a third anode and a third cathode, wherein the third cathode is electrically connected to the second anode, wherein the first light-emitting element, the second light-emitting element, and the third light-emitting element are all single-color light-emitting elements. The first light-emitting element further includes a first semiconductor material layer, the first anode and the first cathode are arranged on the same side of the first semiconductor material layer, and the second light-emitting element further includes a second semiconductor material layer, the second anode and the second cathode are arranged on the same side of the second semiconductor material layer, the second cathode is electrically connected to the first anode through a wire, and the wire is arranged on the first semiconductor material layer and the second semiconductor material layer and is electrically insulated from the first cathode and the second anode. A light-emitting device structure as described in claim 1, wherein the first light-emitting element is a combination of a blue light-emitting element and a red wavelength conversion layer or a red light-emitting element, the second light-emitting element is a combination of a blue light-emitting element and a green wavelength conversion layer or a green light-emitting element, and the third light-emitting element is a blue light-emitting element. The light emitting device structure as described in claim 1, wherein the top view area of the first semiconductor material layer is larger than the top view area of the second semiconductor material layer. A method for operating a light-emitting device structure includes: providing the light-emitting device structure, the light-emitting device structure including: a first light-emitting element including a first anode and a first cathode; a second light-emitting element stacked on the first light-emitting element and including a second anode and a second cathode, wherein the second cathode is electrically connected to the first anode; and a third light-emitting element stacked on the second light-emitting element and including a third anode and a third cathode, wherein the third cathode is electrically connected to the second anode, the first light-emitting element further including a first semiconductor material layer, the first anode and the first cathode being disposed on the same side of the first semiconductor material layer, and the second light-emitting element further including a second semiconductor material layer. layer, the second anode and the second cathode are arranged on the same side of the second semiconductor material layer, the second cathode and the first anode are electrically connected through a wire, and the wire is arranged on the first semiconductor material layer and the second semiconductor material layer and is electrically insulated from the first cathode and the second anode; the voltage difference between the first anode and the first cathode is greater than a first value, so that the first light-emitting element emits a first color light; the voltage difference between the second anode and the second cathode is greater than a second value, so that the second light-emitting element emits a second color light; and the voltage difference between the third anode and the third cathode is greater than a third value, so that the third light-emitting element emits a third color light. The operating method of the light-emitting device structure as described in claim 4, wherein the first light-emitting element is a red light-emitting element, and the first value is different from the third value. The operating method of the light-emitting device structure as described in claim 4, wherein the first light-emitting element is a combination of a blue light-emitting element and a red wavelength conversion layer, and the first value is the same as the third value. The operating method of the light-emitting device structure as described in claim 4, wherein the second light-emitting element is a green light-emitting element, and the second value is different from the third value. The operating method of the light-emitting device structure as described in claim 4, wherein the second light-emitting element is a combination of a blue light-emitting element and a green wavelength conversion layer, and the second value is the same as the third value.