Light-emitting device

Abstract

According to an aspect of the present invention, provided may be a light-emitting device comprising: a substrate; a first light-emitting element disposed on the substrate and generating light of a first emission spectrum having a first dominant wavelength, by a current supplied through the substrate; and a second light-emitting element disposed on the substrate and generating light of a second emission spectrum having a second dominant wavelength and at least partially overlapping the first emission spectrum, by the current supplied through the substrate, wherein the intensity of the first dominant wavelength and the intensity of the second dominant wavelength are different from each other.

Description

light-emitting device

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

[0002] Light-emitting diodes (LEDs) have been widely used recently. LEDs utilize the properties of compound semiconductors to convert electrical signals into forms of light such as infrared, visible light, and ultraviolet light.

[0003] As the light efficiency of light-emitting diodes increases, light-emitting devices are being applied in various fields, including display devices, lighting fixtures, and vehicles.

[0004] Embodiments of the present invention provide a light-emitting device with improved color rendering index (CRI).

[0005] In addition, embodiments of the present invention provide a light-emitting device that can improve color rendering and reduce costs.

[0006] In addition, embodiments of the present invention provide a light-emitting device having a wide color gamut and an increased color reproduction rate.

[0007] In addition, embodiments of the present invention provide a light-emitting device that can improve reliability.

[0008] In addition, embodiments of the present invention provide a light-emitting device with increased light extraction efficiency.

[0009] Furthermore, the embodiments of the present invention aim to provide a light-emitting device that is stable even under temperature changes by solving the problem where the ratio of change by wavelength differs from the pre-designed value due to degradation, etc.

[0010] In addition, embodiments of the present invention provide a light-emitting device with reduced production costs by reducing or eliminating the phosphor content.

[0011] In addition, embodiments of the present invention provide a light-emitting device that can be implemented in a small size.

[0012] According to one aspect of the present invention, a light-emitting device may be provided comprising: a substrate; a first light-emitting element disposed on the substrate and generating light of a first light-emitting spectrum having a first frequency by means of a current supplied through the substrate; and a second light-emitting element disposed on the substrate and generating light of a second light-emitting spectrum having a second frequency and at least partially overlapping with the first light-emitting spectrum by means of a current supplied through the substrate, wherein the intensity of the first frequency and the intensity of the second frequency are different.

[0013] In addition, a light-emitting device may be provided in which the intensity of the first frequency changes according to the current density supplied to the first light-emitting element, and the intensity of the second frequency changes according to the current density supplied to the second light-emitting element.

[0014] Additionally, a light-emitting device may be provided such that when the current density supplied to the first light-emitting element increases, the wavelength of the first frequency decreases and the intensity of the first frequency increases, when the current density supplied to the first light-emitting element decreases, the wavelength of the first frequency increases and the intensity of the first frequency decreases, when the current density supplied to the second light-emitting element increases, the wavelength of the second frequency decreases and the intensity of the second frequency increases, and when the current density supplied to the second light-emitting element decreases, the wavelength of the second frequency increases and the intensity of the second frequency decreases.

[0015] Additionally, a light-emitting device may be provided, further comprising a controller for controlling the current density supplied to the first light-emitting element and the current density supplied to the second light-emitting element to control the first frequency and the second frequency.

[0016] In addition, a light-emitting device may be provided, wherein the controller controls the current density supplied to the first light-emitting element to be smaller than the current density supplied to the second light-emitting element.

[0017] Additionally, the controller is configured to further control the current so that current is supplied to the first light-emitting element and the second light-emitting element for a predetermined current supply time, and a light-emitting device may be provided in which the first current supply time during which current is supplied to the first light-emitting element is greater than the second current supply time during which current is supplied to the second light-emitting element.

[0018] In addition, a light-emitting device may be provided in which the first current supply time during which current is supplied to the first light-emitting element is faster than the second current supply time during which current is supplied to the second light-emitting element.

[0019] Additionally, a light-emitting device may be provided, wherein the controller is configured to further control the current such that a section is formed in which no current is supplied to the first light-emitting element and the second light-emitting element between a first current supply time in which current is supplied to the first light-emitting element and a second current supply time in which current is supplied to the second light-emitting element.

[0020] In addition, a light-emitting device may be provided in which the time of the interval during which the current is not supplied is shorter than the first current supply time during which current is supplied to the first light-emitting element.

[0021] In addition, a light-emitting device may be provided in which the time of the interval during which the current is not supplied is longer than the first current supply time during which current is supplied to the first light-emitting element.

[0022] Additionally, a light-emitting device may be provided, comprising a third light-emitting element disposed on the substrate and generating light of a third light-emitting spectrum having a third frequency and at least partially overlapping with the second light-emitting spectrum by means of a current supplied through the substrate, wherein the controller is configured to further control the current density supplied to the third light-emitting element to control the third frequency, such that the current density supplied to the third light-emitting element is greater than the current density supplied to the second light-emitting element.

[0023] In addition, the controller supplies a current waveform to at least one of a plurality of light-emitting elements, the current waveform has a first current density in a first time interval and a second current density in a second time interval, and the first charge density per unit area can be defined by Equation 1.

[0024] [Mathematical Formula 1]

[0025]

[0026] Here, C1 is the first charge density per unit area, J1 is the first current density, and Ta1 is the first time interval.

[0027] In addition, the second charge density per unit area can be defined by Equation 2.

[0028] [Mathematical Formula 2]

[0029]

[0030] Here, C2 is the second charge density per unit area, J2 is the second current density, and Tb1 is the second time interval.

[0031] In addition, the first charge density C1 and the second charge density C2 per unit area can be expressed as Equation 3.

[0032] [Mathematical Formula 3]

[0033]

[0034] In addition, each current supply time may be shorter than each current supply time.

[0035] In addition, the above current supply time can be expressed as Equation 4.

[0036] [Mathematical Formula 4]

[0037]

[0038] Additionally, a light-emitting device may be provided in which the first light-emitting element and the second light-emitting element generate light such that an overlapping spectrum is formed in which at least a portion of the first light-emitting spectrum and the second light-emitting spectrum overlap each other, and a plurality of peaks are formed in the overlapping spectrum.

[0039] In addition, a light-emitting device may be provided for the above-mentioned superposition spectrum having a color temperature corresponding to white light.

[0040] Additionally, a light-emitting device may be provided, wherein each of the first light-emitting element and the second light-emitting element comprises: a first conductivity type semiconductor layer; an active region stacked above the first conductivity type semiconductor layer; and a second conductivity type semiconductor layer stacked above the active region.

[0041] Additionally, a light-emitting device may be provided in which each of the first light-emitting element and the second light-emitting element comprises: a first conductivity type semiconductor layer; a superlattice layer stacked above the first conductivity type semiconductor layer; and a second conductivity type semiconductor layer stacked above the superlattice layer, wherein the superlattice layer comprises indium gallium nitride.

[0042] Additionally, a light-emitting device may be provided in which the superlattice layer is formed in a plurality of ways, and the plurality of superlattice layers include a first superlattice layer stacked above the first conductive semiconductor layer; and a second superlattice layer stacked above the first superlattice layer, wherein the content of indium included in the first superlattice layer and the content of indium included in the second superlattice layer are different.

[0043] In addition, according to one aspect of the present invention, a light-emitting device may be provided comprising: a substrate; a first light-emitting element disposed on the substrate and generating light of a first light-emitting spectrum having a first frequency; and a second light-emitting element disposed on the substrate and generating light of a second light-emitting spectrum having a second frequency and at least partially overlapping with the first light-emitting spectrum, wherein each of the first light-emitting element and the second light-emitting element comprises: a first conductive semiconductor layer; an active region stacked above the first conductive semiconductor layer; a second conductive semiconductor layer stacked above the active region; a first electrode electrically connected to the second conductive semiconductor layer; and a second electrode electrically connected to the first conductive semiconductor layer, wherein the second electrode of the first light-emitting element and the second electrode of the second light-emitting element are electrically connected to the second conductive semiconductor layer of the first light-emitting element and the second light-emitting element.

[0044] Additionally, a light-emitting device may be provided comprising: a substrate; a first active region disposed on the substrate and generating light of a first emission spectrum having a first frequency by means of a current supplied through the substrate; and a second active region disposed on the substrate and generating light of a second emission spectrum having a second frequency and at least partially overlapping with the first emission spectrum by means of a current supplied through the substrate, wherein the intensity at the first frequency and the intensity at the second frequency are different.

[0045] In addition, a light-emitting device may be provided in which the intensity at the first frequency changes according to the current density supplied to the first active region, and the intensity at the second frequency changes according to the current density supplied to the second active region.

[0046] Additionally, a light-emitting device may be provided, further comprising a controller configured to control the current density supplied to the first active region and the current density supplied to the second active region so as to control the first frequency and the second frequency.

[0047] The embodiments of the present invention have the effect of improving color rendering index (CRI).

[0048] In addition, the embodiments of the present invention have the effect of improving color rendering and reducing cost increases compared to conventional methods.

[0049] In addition, the embodiments of the present invention have the effect of having a wide color gamut and increasing the color reproduction rate.

[0050] In addition, the embodiments of the present invention have the effect of improving reliability.

[0051] In addition, the embodiments of the present invention have the effect of increasing light extraction efficiency.

[0052] In addition, the embodiments of the present invention have the effect of being stable even under temperature changes by solving the problem where the ratio between the notochord light, red light, and green light differs from the pre-designed ratio due to degradation, etc.

[0053] In addition, the embodiments of the present invention have the effect of reducing production costs by reducing the phosphor content.

[0054] In addition, the embodiments of the present invention have the effect that the light-emitting device can be implemented in a small size.

[0055] FIG. 1 is a drawing showing a lighting device including a light-emitting device according to a first embodiment of the present invention.

[0056] FIG. 2 is a drawing showing a display device including a light-emitting device according to a first embodiment of the present invention.

[0057] FIG. 3 is a drawing showing a light-emitting element of a light-emitting device according to a first embodiment of the present invention including a first active region and a second active region.

[0058] Figure 4 is a diagram showing the light-emitting element of Figure 3 with a third active region further included.

[0059] Figure 5 is a graph showing the change in spectrum according to the current supplied to the light-emitting element of the light-emitting device of Figure 3.

[0060] Figure 6 is an enlarged graph of the spectrum of different currents in Figure 5.

[0061] FIG. 7 is a drawing showing a light-emitting element placed on a substrate according to a second embodiment of the present invention.

[0062] Figure 8 is a cross-sectional view of the light-emitting element of Figure 7 cut along A-A'.

[0063] FIG. 9 is a drawing showing a light-emitting element placed on a substrate according to a third embodiment of the present invention.

[0064] FIG. 10 is a diagram showing a plurality of emission spectra of the light-emitting device of FIG. 9.

[0065] Figure 11 is a diagram showing that multiple emission spectra of Figure 10 change according to current density.

[0066] FIG. 12 is a diagram showing a superimposed spectrum in which multiple emission spectra of FIG. 10 are superimposed.

[0067] FIG. 13 is a drawing showing a plurality of light-emitting elements arranged on a substrate according to a fourth embodiment of the present invention.

[0068] FIG. 14 is a diagram showing a first current waveform supplied to the light-emitting device of the present invention.

[0069] FIG. 15 is a diagram showing a second current waveform supplied to the light-emitting device of the present invention.

[0070] FIG. 16 is a diagram showing a third current waveform supplied to the light-emitting device of the present invention.

[0071] FIG. 17 is a diagram showing the fourth current waveform and the fifth current waveform supplied to the light-emitting device of the present invention.

[0072] FIG. 18 is a diagram showing a first current waveform and a second current waveform supplied to the light-emitting device of the present invention.

[0073] FIG. 19 is a diagram showing the sixth current waveform supplied to the light-emitting device of the present invention.

[0074] FIG. 20 is a diagram showing the seventh current waveform supplied to the light-emitting device of the present invention.

[0075] FIG. 21 is a diagram showing the eighth current waveform supplied to the light-emitting device of the present invention.

[0076] FIG. 22 is a diagram showing the ninth current waveform supplied to the light-emitting device of the present invention.

[0077] FIG. 23 is a drawing showing a light-emitting element placed on a substrate according to the fifth embodiment of the present invention.

[0078] FIG. 24 is a drawing showing a light-emitting element placed on a substrate according to the 6th embodiment of the present invention.

[0079] FIG. 25 is a drawing showing a light-emitting element placed on a substrate according to the seventh embodiment of the present invention.

[0080] FIG. 26 is a drawing showing a light-emitting element placed on a substrate according to the eighth embodiment of the present invention.

[0081] FIG. 27 is a graph showing the rate of change of frequency according to the current density supplied to the light-emitting element of the present invention.

[0082] FIG. 28 is a drawing showing a light-emitting device according to the eighth embodiment of the present invention.

[0083] FIG. 29 is a diagram showing a superimposed spectrum in which multiple emission spectra are superimposed.

[0084] In the following description, numerous specific details are described for the purpose of explanation and to provide a complete understanding of the various embodiments or implementations of the present disclosure. As used herein, “Embodiments” and “Implementations” are interchangeable terms indicating non-limiting examples of devices or methods utilizing one or more of the concepts of the invention disclosed herein. However, it will be apparent that various embodiments may be implemented without utilizing these specific details or by utilizing one or more equivalent arrangements. In other examples, known structures and devices are illustrated in block diagram form to avoid unnecessarily obscuring the various embodiments. Furthermore, while various embodiments may differ from one another, they do not need to be exclusive. For example, specific shapes, configurations, and characteristics of an embodiment may be used or implemented in other embodiments without departing from the scope of the concept of the invention.

[0085] Unless otherwise specified, the illustrated embodiments should be understood as providing exemplary features of varying details in some ways in which the concept of the present invention can actually be realized. Therefore, unless otherwise specified, features, components, modules, layers, membranes, panels, regions and / or modes of various embodiments (hereinafter referred to individually or collectively as “elements”) may be combined, separated, interchanged, and / or rearranged differently without departing from the scope of the concept of the present invention.

[0086] The use of cross-hatching and / or shading in the attached drawings is generally provided to clarify the boundaries between adjacent elements. As such, the presence or absence of cross-hatching or shading, unless otherwise specified, does not imply or indicate any preference or requirement regarding the specific material, material properties, dimensions, proportions, commonalities between the exemplified elements, or any other features, attributes, and characteristics of the elements. Additionally, in the attached drawings, the size and relative size of the elements may be exaggerated for clarity and / or illustrative purposes. When embodiments are implemented differently, specific process sequences may be performed differently from the described order. For example, two consecutively described processes may be performed substantially simultaneously or in an order opposite to the described order. Also, the same reference numerals indicate the same elements.

[0087] When an element such as a layer is referred to as being "on", "connected to," or "coupled to" another element or layer, said element may be directly on, connected to, or coupled to the other element or layer, or an interposed element or layer may exist. However, when an element or layer is referred to as being "directly on", "directly connected to," or "directly coupled to" another element or layer, no interposed element or layer exists. To this end, the term "connected" may refer to a physical, electrical, and / or fluid connection with or without an interposed element. Furthermore, the DR1-axis, DR2-axis, and DR3-axis are not limited to the three axes of an orthogonal coordinate system, such as the x, y, and z axes, and may be interpreted in a broader sense. For example, the DR1-axis, DR2-axis, and DR3-axis may be perpendicular to each other, or they may represent different directions that are not perpendicular to each other. For the purposes of this disclosure, “one or more of X, Y, and Z” and “one or more selected from the group consisting of X, Y, and Z” may be interpreted as only X, only Y, only Z, or any combination of two or more of X, Y, and Z, such as, for example, XYZ, XYY, YZ, and ZZ. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed articles.

[0088] Although terms such as “first,” “second,” etc., may be used herein to describe various forms of elements, these elements shall not be limited by these terms. These terms are used to distinguish one element from another. Therefore, the first element discussed below may be named the second element without departing from the teachings of the present disclosure.

[0089] Spatially relative terms such as “below,” “under,” “immediately below,” “lower,” “above,” “upper,” “upper,” “higher,” and “side” (e.g., as in “side wall”) may be used for descriptive purposes and thereby to describe the relationship between one element and another element(s) as illustrated in the drawings. Spatially relative terms are intended to include different orientations of the device in use, operation, and / or manufacture in addition to the orientations illustrated in the drawings. For example, if the device in the drawings is inverted, the element described as “below” or “under” another element or feature will be oriented “above” the other element or feature. Therefore, the exemplary term “below” may include both upper and lower orientations. Additionally, the device may be oriented differently (e.g., rotated 90° or oriented in a different orientation), and thus, spatially relative descriptors used herein may also be interpreted accordingly.

[0090] The technical terms used in this specification are intended to describe specific embodiments and are not limiting. The singular form used in this specification also includes the plural form unless the context clearly indicates otherwise. Additionally, the terms “comprising,” “comprising,” “comprising,” and / or “comprising” used in this specification specify the presence of the mentioned features, integers, steps, operations, elements, components, and / or groups thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Furthermore, the terms “substantially,” “about,” and other similar terms used in this specification are used to indicate approximation rather than degree, and are used to describe inherent deviations of measured, calculated, and / or provided values ​​that may be recognized by a person of ordinary knowledge in the art.

[0091] Various embodiments are described below with reference to cross-sectional and / or exploded drawings, which are schematic examples of idealized embodiments and / or intermediate structures. As such, variations from the shapes in the drawings may be expected, for example, as a result of manufacturing techniques and / or tolerances. Therefore, the embodiments disclosed herein should not be interpreted as being limited to the shapes of specific illustrated regions, but should be interpreted to include, for example, variations in shape resulting from manufacturing. In this way, the regions illustrated in the drawings may be schematic in nature, and the shapes of these regions may not reflect the actual shapes of the regions of the device, and thus are not intended to have a limiting meaning.

[0092] As is customary in the art, some embodiments may be illustrated and described in the accompanying drawings in terms of functional blocks, units, and / or modules. Those skilled in the art will understand that these blocks, units, and / or modules are physically implemented by electronic (or optical) circuits, such as logic circuits, discrete components, microprocessors, wiring circuits, memory elements, and wiring connections, formed using semiconductor-based manufacturing technology or other manufacturing technology. Where blocks, units, and / or modules are implemented by microprocessors or other similar hardware, they may be programmed and controlled using software (e.g., microcode) to perform the various functions discussed herein, and may optionally be driven by firmware and / or software. Additionally, each block, unit, and / or module may be implemented by dedicated hardware, or as a combination of dedicated hardware for performing some functions and a processor for performing other functions (e.g., one or more programmed processors and associated circuits). Additionally, each of the blocks, units, and / or modules of some embodiments may be physically separated into two or more interacting and individual blocks, units, and / or modules without departing from the scope of the concept of the present invention. Additionally, the blocks, units, and / or modules of some embodiments may be physically combined into more complex blocks, units, and / or modules without departing from the scope of the concept of the present invention.

[0093] Unless otherwise defined, all terms used herein (including technical or scientific terms) have the same meaning as commonly understood by those skilled in the art to which this disclosure pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with that meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this specification.

[0094] Hereinafter, a light-emitting device (1) according to the first embodiment of the present invention will be described.

[0095] Referring to FIGS. 1 and 2, a light-emitting device (1) according to the first embodiment of the present invention can generate light. Such a light-emitting device (1) may be included in a window, windshield, rear window, taillight, headlight, rear lamp, tail lamp, interior light, brake light, etc. of a vehicle.

[0096] For example, a light-emitting device (1) may be included in a lighting device (2). The lighting device (2) may include a lighting body (10) and a lighting cover (20). A light-emitting device (1) may be placed in the lighting body (10). Various components, such as elements and wiring for the operation of the light-emitting device (1), may be placed inside the lighting body (10). Additionally, the lighting body (10) may include a heat sink and a socket connected to an external power source. Light may be transmitted through the lighting cover (20). The lighting cover (20) may be combined with the lighting body (10) to cover the light-emitting device (1).

[0097] As another example, the light-emitting device (1) may be included in the display device (3). The display device (3) may be a display device. The display device (3) may include a display panel (30), a driving substrate (40), an optical sheet (50), and a lower cover (60). The display panel (30) may include a thin-film transistor substrate and a color filter substrate bonded together so as to maintain a uniform cell gap facing each other. Additionally, the display panel (30) may include a liquid crystal layer disposed between the thin-film transistor substrate and the color filter substrate. A driving substrate that supplies driving signals to gate lines and data lines may be located at the edge of the display panel (30).

[0098] The driving board (40) can be electrically connected to the display panel (30) by a Chip On Film (COF). The COF can be changed to a Tape Carrier Package (TCP). The optical sheet (50) may include a diffusion sheet, a light-concentrating sheet, and a protective sheet. The optical sheet (50) may be composed of one diffusion sheet and two light-concentrating sheets, or two diffusion sheets and one light-concentrating sheet. The lower cover (60) has a structure with an open upper surface and can accommodate the optical sheet (50) and the light-emitting device (1). In other words, the light-emitting device (1) can be placed between the optical sheet (50) and the lower cover (60). Additionally, the display device (3) may further include a reflective sheet placed on the upper or lower surface of the light-emitting device (1). The reflective sheet can reflect light toward the optical sheet (50).

[0099] This light-emitting device (1) may include a substrate (100), a light-emitting element (200), and a controller (300).

[0100] A light-emitting element (200) and a controller (300) may be disposed on the substrate (100). For example, the substrate (100) may be a printed circuit board (PCB) on which an electrical circuit is formed. Additionally, the substrate (100) may include an alloy comprising one or more of Cu, Zn, Au, Ni, Al, Mg, Cd, Be, W, Mo, Si, Ag, and Fe, or some thereof. However, this is merely an example, and the substrate (100) may include one or more of FR1, CEM-1, and FR-4. Here, FR1 is a material in which copper foil and laminate paper are laminated, and CEM-1 is a material in which copper foil, glass fiber fabric, laminate paper, and glass fiber fabric are sequentially laminated. Additionally, FR-4 is a material in which copper foil and glass fiber fabric or glass fiber fabric are laminated. In addition, the substrate (100) may include ceramics such as alumina (Al2O3), aluminum nitride (AlN), or ZTA (Zirconia Toughened Alumina). Furthermore, the substrate (100) may include a growth substrate for growing a printed circuit board and a light-emitting element (200).

[0101] Referring further to FIG. 3, the light-emitting element (200) can generate light. For example, the light-emitting element (200) may be a device that converts electrical energy into light, such as a light-emitting diode, a laser diode, or an organic light-emitting diode. The light-emitting element (200) can generate one or more of UVC (200nm~280nm), UVB (280nm~315nm), UVA (315nm~420nm), blue light, green light, yellow light, red light, infrared light, and white light. The light-emitting element (200) can generate light by being electrically connected to the substrate (100) and receiving power from an external source. Additionally, the light-emitting element (200) may be formed in multiple units. The multiple light-emitting elements (200) may include a first light-emitting element (200a) and a second light-emitting element (200b). The first light-emitting element (200a) and the second light-emitting element (200b) can emit light of different peak wavelengths.

[0102] Each of the plurality of light-emitting elements (200) may include a buffer layer (201), an undoft layer (202), a first conductivity type semiconductor layer (203), a strain control layer (204), a superlattice layer (205), an active region (206), an electron block layer (207), a second conductivity type semiconductor layer (208), a transparent electrode layer (209), and an electrode (210).

[0103] The buffer layer (201) may be a layer disposed on the substrate (100) for growing a gallium nitride-based semiconductor layer. For example, the buffer layer (201) may include AlGaN. The buffer layer (201) can relieve thermal stress by adjusting the difference in thermal expansion coefficients between the gallium nitride-based semiconductor layer and the substrate (100). The buffer layer (201) can prevent defects or non-uniformity of the substrate (100) from propagating to the gallium nitride-based semiconductor layer. Additionally, the buffer layer (201) can reduce the occurrence of defects by buffering the difference in lattice constants between the substrate (100) and the gallium nitride-based semiconductor layer.

[0104] The undoft layer (202) can be laminated onto the buffer layer (201). The undoft layer (202) can control the current flow of the substrate (100) or form an electrical barrier. In other words, the undoft layer (202) can act as an insulating layer.

[0105] The first conductivity semiconductor layer (203) may include n-type impurities (e.g., Si, Ge, Sn). This first conductivity semiconductor layer (203) may be an n-type semiconductor layer. However, this is merely an example, and the first conductivity semiconductor layer (203) may include p-type impurities. Additionally, the first conductivity semiconductor layer (203) may be electrically connected to the substrate (100) through an electrode (210).

[0106] The strain control layer (204) can be laminated onto the first conductive semiconductor layer (203). The strain control layer (204) is placed between the first conductive semiconductor layer (203) and the superlattice layer (205) to reduce the difference in lattice constants between the first conductive semiconductor layer (203) and the superlattice layer (205). This strain control layer (204) can prevent defects from occurring in the first conductive semiconductor layer (203) and the superlattice layer (205) and can strengthen the bonding force between the first conductive semiconductor layer (203) and the superlattice layer (205). The strain control layer (204) can alleviate thermal stress caused by the difference in thermal expansion coefficients between the first conductive semiconductor layer (203) and the superlattice layer (205), thereby increasing stability and reliability. The strain control layer (204) can optimize the flow of current and charge mobility by improving the electrical junction between the first conductivity type semiconductor layer (203) and the superlattice layer (205).

[0107] The superlattice layer (205) can be stacked on the strain control layer (204) to generate light. The superlattice layer (205) may include a plurality of material layers containing different materials. The plurality of material layers may be stacked alternately. The materials may be composed of GaAs, AlGaAs, InGaN, GaN, InGaAs, InP, etc. Hereinafter, the superlattice layer (205) is described as including an InGaN layer and a GaN layer that are stacked alternately, but is not limited thereto. The superlattice layer (205) may include one or more of the first superlattice layer (205a) and the second superlattice layer (205b).

[0108] The first superlattice layer (205a) may be laminated on the strain control layer (204). The first superlattice layer (205a) may include an InGaN layer and a GaN layer laminated alternately with each other in 3 to 4 cycles. The thickness of the InGaN layer of the first superlattice layer (205a) and the thickness of the GaN layer of the first superlattice layer (205a) may be formed differently. For example, the thickness of the InGaN layer of the first superlattice layer (205a) may be smaller than the thickness of the GaN layer of the first superlattice layer (205a).

[0109] A second superlattice layer (205b) may be stacked on the first superlattice layer (205a). The second superlattice layer (205b) may include InGaN layers and GaN layers stacked alternately with more periods than the first superlattice layer (205a). For example, the second superlattice layer (205b) may include InGaN layers and GaN layers stacked alternately with 5 to 6 periods. The content of In in the InGaN layer of the second superlattice layer (205b) and the content of In in the InGaN layer of the first superlattice layer (205a) may be different. For example, the content of In in the InGaN layer of the second superlattice layer (205b) may be formed to be greater than the content of In in the InGaN layer of the first superlattice layer (205a). These first superlattice layer (205a) and second superlattice layer (205b) can have different bandgap energies. In other words, the first superlattice layer (205a) and second superlattice layer (205b) can generate light having different peak wavelengths.

[0110] The active region (206) may be stacked on the superlattice layer (205). The active region (206) may generate light. The active region (206) may include a well layer and a barrier layer. The active region (206) may have a single quantum well structure including a single well layer or a multiple quantum well structure including multiple well layers. For example, the number of well layers may be 1 to 10. The well layer may include InGaN. The well layer may include a higher content of In than the barrier layer to generate long-wavelength light. The composition ratio of In in the well layer may be 0.15 or more and 0.2 or less with respect to the total composition of the well layer. The barrier layer may include a GaN layer. Additionally, the active region (206) may include one or more of a first active region (206a) and a second active region (206b). The first active region (206a) and the second active region (206b) can generate light of different peak wavelengths.

[0111] The first active region (206a) can generate light with a peak wavelength between 440 nm and 470 nm. In other words, the first active region (206a) can generate blue light. The first active region (206a) may include 5 to 7 well layers.

[0112] The second active region (206b) can generate light having a peak wavelength different from the light generated in the first active region (206a) and the light generated in the third active region (206c). As illustrated in FIG. 4, for example, the second active region (206b) can generate light with a peak wavelength between 500 nm and 600 nm. In other words, the second active region (206b) can generate green light. The second active region (206b) may include 5 to 7 well layers.

[0113] Referring further to FIG. 4, the active region (206) may further include a third active region (206c). The third active region (206c) may generate light having a peak wavelength different from the light generated in the second active region (206b) and the light generated in the first active region (206a). For example, the third active region (206c) may generate light having a peak wavelength between 600 nm and 670 nm. In other words, the third active region (206c) may generate red light. The third active region (206c) may include 5 to 10 well layers.

[0114] The electron block layer (207) can be laminated on the active region (206). The electron block layer (207) can be formed along the surface of the active region (206). The electron block layer (207) is placed between the active region (206) and the second conductive semiconductor layer (208) to prevent electrons from escaping into the second conductive semiconductor layer (208). In other words, the electron block layer (207) can reduce light crosstalk and improve luminous efficiency by keeping electrons in the active region (206).

[0115] The second conductivity semiconductor layer (208) may contain p-type impurities (e.g., Mg, Sr, or Ba). In other words, the second conductivity semiconductor layer (208) may be a p-type semiconductor layer. However, this is merely an example, and the second conductivity semiconductor layer (208) may contain n-type impurities. Additionally, the second conductivity semiconductor layer (208) may be electrically connected to a substrate through an electrode (210).

[0116] The transparent electrode layer (209) can be laminated onto the second conductive semiconductor layer (208). For example, the transparent electrode layer (209) may include a conductive oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO).

[0117] The electrodes (210) may be formed in multiple numbers and electrically connected to the first conductive semiconductor layer (203) and the substrate (100), or electrically connected to the second conductive semiconductor layer (208) and the substrate (100). Through these electrodes (210), the light-emitting element (200) can receive current and generate light. The electrodes (210) may be formed of Cr, Pt, Au, etc. The multiple electrodes (210) may include a first electrode (210a) and a second electrode (210b).

[0118] The first electrode (210a) can be electrically connected to the second conductivity type semiconductor layer (208) and the substrate (100). The second electrode (210b) can be electrically connected to the first conductivity type semiconductor layer (203) and the substrate (100).

[0119] A controller (300) is disposed on a substrate (100) and can change the spectrum of light emitted from a plurality of light-emitting elements (200) by controlling the current supplied to the plurality of light-emitting elements (200). For example, the controller (300) may be a driving element or a driving circuit that controls one or more of the magnitude, current density, and current supply time of the current supplied to the plurality of light-emitting elements (200) disposed on the substrate (100). By means of such a controller (300), the plurality of light-emitting elements (200) can generate light that forms a light emission spectrum having a plurality of peaks. Meanwhile, the controller (300) may be implemented by one or more of a computing device including a microprocessor, a switching circuit, a measuring device such as a sensor, and a memory. Since such implementation methods are obvious to those skilled in the art, further detailed description is omitted.

[0120] Referring to FIGS. 5 and 6, the plurality of peaks included in the emission spectrum may include a main peak and a sub-peak. Accordingly, the dominant wavelength of the emission spectrum of the light-emitting device may have a value different from that of the main peak and the sub-peak.

[0121] For example, the main peak may be located in a wavelength range longer than 580 nm. The light intensity at the auxiliary peak may be lower than the light intensity at the main peak. The auxiliary peak may be located in a short wavelength range of 400 nm to 430 nm. For example, the auxiliary peak may be located in a wavelength range shorter than 420 nm. As another example, the main peak may be shorter than the auxiliary peak. For example, the main peak may be located in the blue region of 440 nm to 480 nm, and the auxiliary peak may be located in a longer wavelength range of 500 nm to 700 nm. In this case, the wavelength may have a value in the region between the main peak and the auxiliary peak.

[0122] As another example, the auxiliary peak may be located in a wavelength range of 420 nm to 580 nm. Additionally, the auxiliary peak may be formed as a plurality. The plurality of auxiliary peaks may be located in different wavelength ranges. The plurality of auxiliary peaks may include a first auxiliary peak and a second auxiliary peak. The wavelength difference between the first auxiliary peak and the second auxiliary peak may be at least 50 nm and at most 200 nm. At least one of the first auxiliary peak and the second auxiliary peak may be located in a wavelength range different from the main peak. The wavelength difference between at least one of the first auxiliary peak and the second auxiliary peak and the main peak may be 150 nm or more. Through this, a sufficient area can be secured to enable the realization of various colors. In this case, the wavelength may have a value in the region between the main peak and the auxiliary peak.

[0123] The controller (300) can control one or more of the current and current density applied to the light-emitting element (200). The controller (300) can increase the intensity of light or current density at the main peak and auxiliary peak by increasing the current supplied to the light-emitting element (200). For example, the controller (300) can supply currents such as 0.2 mA, 1 mA, and 5 mA to the light-emitting element (200). When the current supplied to the light-emitting element (200) increases, the intensity of the main peak and auxiliary peak increases, and the wavelength of the main peak can shift toward the short wavelength side. In addition, when the current supplied to the light-emitting element (200) increases, the ratio of height to full width in the light emission spectrum can also increase. In other words, when the current supplied to the light-emitting element (200) increases, the color purity of the light emitted from the light-emitting element (200) can be improved.

[0124] Hereinafter, with reference to FIGS. 7 and FIGS. 8, a light-emitting element (200) disposed on a substrate (100) according to a second embodiment of the present invention will be described.

[0125] In describing the second embodiment, there is a difference in that the electrodes (210) of a plurality of light-emitting elements (200) can be formed integrally, and this difference will be explained in detail.

[0126] The first electrode (210a) of the first light-emitting element (200a) and the second light-emitting element (200b) may have the first electrode (210a) formed integrally. Additionally, the second electrode (210b) of the first light-emitting element (200a) and the second electrode (210b) of the second light-emitting element (200b) may have the second electrode (210b) formed integrally. If one or more of the first electrode (210a) and the second electrode (210b) of the first light-emitting element (200a) and the second light-emitting element (200b) are formed integrally, the difficulty of design may be reduced.

[0127] Additionally, the first light-emitting element (200a) and the second light-emitting element (200b) may include different superlattice layers (205) having different bandgap energies. For example, the superlattice layer (205) of the first light-emitting element (200a) may include a first superlattice layer (205a), and the superlattice layer (205) of the second light-emitting element (200b) may include a second superlattice layer (205b). Accordingly, the first light-emitting element (200a) and the second light-emitting element (200b) may generate light having different peak wavelengths.

[0128] Hereinafter, with reference to FIGS. 9 to 12, a light-emitting element (200) disposed on a substrate according to a third embodiment of the present invention will be described.

[0129] In describing the third embodiment, there is a difference in that the plurality of light-emitting elements (200) include a first light-emitting element (200a), a second light-emitting element (200b), and a third light-emitting element (200c), and this difference will be explained mainly.

[0130] The first light-emitting element (200a) can generate light that forms a first light emission spectrum (S1). The first light-emitting element (200a) can generate light in which the main peak spectrum is located between 440 nm and 470 nm. In other words, the first light emission spectrum (S1) may have a first main peak wavelength located in the blue wavelength band. In this case, the first main peak wavelength may be a peak wavelength in the spectrum excluding auxiliary peaks. Additionally, the first main peak wavelength may include multiple peaks. The multiple peaks of the first main peak wavelength may include a first main peak and a first auxiliary peak.

[0131] The first main peak can be located between 420 nm and 480 nm. In other words, the first main peak can be located in the blue wavelength range. At this time, the dominant wavelength of the first main peak can be located between 420 nm and 480 nm. The dominant wavelength of the first main peak is called the first wavelength. The first wavelength can be located between the first auxiliary peak and the first main peak. The wavelength difference between the first auxiliary peak and the first main peak can be less than 10 nm.

[0132] One or more first auxiliary peaks may be formed in the first spectrum. These first auxiliary peaks may be located in a wavelength band different from the first main peak. In other words, one or more first auxiliary peaks may be located in a wavelength band other than the blue wavelength region. For example, the first auxiliary peak may be located in the green wavelength region band or the red wavelength region band. Additionally, the first auxiliary peak may have a longer wavelength than the first main peak.

[0133] Additionally, the first emission spectrum (S1) may change according to the current density supplied to the first light-emitting element (200a). The first emission spectrum (S1) may be formed into a first-1 emission spectrum (S1-1) or a first-2 emission spectrum (S1-2) depending on the current density. For example, the first frequency of the first light-emitting element (200a) may have a rate of change of frequency according to current density of WD1 as shown in FIG. 27, which will be described later. Meanwhile, as shown in Equation 1 below, the current density may be a current value according to the area of ​​the light-emitting element (200). The area of ​​the light-emitting element (200) can be calculated as the product of the horizontal length and the vertical length of the light-emitting element (200).

[0134] [Mathematical Formula 1]

[0135]

[0136] A first-1 emission spectrum (S1-1) can be formed by light generated from a first emission element (200a) when the current density supplied to the first emission element (200a) is greater than the current density supplied to the first emission element (200a) to form a first-2 emission spectrum (S1-2). The wavelength of the first frequency of the first-1 emission spectrum (S1-1) may be smaller than the wavelength of the first frequency of the first-2 emission spectrum (S1-2). Additionally, the intensity of the first frequency of the first-1 emission spectrum (S1-1) may be greater than the intensity of the first frequency of the first-2 emission spectrum (S1-2).

[0137] A first-2 emission spectrum (S1-2) can be formed by light generated from a first emission element (200a) when the current density supplied to the first emission element (200a) is smaller than the current density supplied to the first emission element (200a) to form a first-1 emission spectrum (S1-1). The wavelength of the first wavelength of the first-2 emission spectrum (S1-2) may be greater than the wavelength of the first frequency of the first-1 emission spectrum (S1-1). Additionally, the intensity at the second frequency of the first-2 emission spectrum (S1-2) may be smaller than the intensity at the second frequency of the first-1 emission spectrum (S1-1).

[0138] The second light-emitting element (200b) can generate light that forms a second light-emitting spectrum (S2). For example, the second frequency of the second light-emitting element (200b) may have a rate of change of frequency according to current density of WD2 as illustrated in FIG. 27, which will be described later. The second light-emitting element (200b) can generate light in which the main peak wavelength is located between 500 nm and 600 nm. In other words, the second light-emitting spectrum (S2) may have a second main peak wavelength located in the green wavelength band. At this time, the second main peak wavelength may be the main peak wavelength in the spectrum excluding the auxiliary peak. In addition, the second main peak wavelength may have one or more peaks. The second main peak wavelength may include a second main peak and a second auxiliary peak, but is not limited thereto.

[0139] The second main peak can be located between 500 nm and 600 nm. In other words, the second main peak can be located in the green wavelength range. In this case, the wavelength of the second main peak can be located between 500 nm and 600 nm. The wavelength of the second main peak is called the second wavelength. The wavelength difference between the second auxiliary peak and the second main peak can be less than 12 nm. The second wavelength can be a value between the second main peak and the second auxiliary peak.

[0140] One or more second auxiliary peaks may be formed in the second emission spectrum (S2). These second auxiliary peaks may be located in a wavelength band different from the second main peak. In other words, one or more second auxiliary peaks may be located in a wavelength band other than the green wavelength region. For example, the second auxiliary peaks may be located in the blue wavelength region band or the red wavelength region band. Additionally, the second auxiliary peaks may have a longer wavelength than the second main peak. In this case, the second wavelength may be longer than the second main peak.

[0141] Additionally, the second emission spectrum (S2) may change according to the current density supplied to the second emission element (200b). Depending on the current density, the second emission spectrum (S2) may be formed into a second-1 emission spectrum (S2-1) and a second-2 emission spectrum (S2-2).

[0142] The second-1 emission spectrum (S2-1) can be formed by light generated from the second emission element (200b) when the current density supplied to the second emission element (200b) is greater than the current density supplied to the second emission element (200a) to form the second-2 emission spectrum (S2-2). The wavelength of the second frequency of the second-1 emission spectrum (S2-1) may be smaller than the wavelength of the second frequency of the second-2 emission spectrum (S2-2). Additionally, the intensity at the second frequency of the second-1 emission spectrum (S2-1) may be greater than the intensity at the second frequency of the second-2 emission spectrum (S2-2). The intensity of the second frequency of the second-1 emission spectrum (S2-1) can be formed to be smaller than the intensity at the first frequency of the first-1 emission spectrum (S1-1).

[0143] The second-2 emission spectrum (S2-2) can be formed by light generated from the second emission element (200b) when the current density supplied to the second emission element (200b) is smaller than the current density supplied to the second emission element (200b) to form the second-1 emission spectrum (S2-1). The wavelength of the second frequency of the second-2 emission spectrum (S2-2) may be larger than the wavelength of the second frequency of the second-1 emission spectrum (S2-1). Additionally, the intensity at the second frequency of the second-2 emission spectrum (S2-2) may be smaller than the intensity at the second frequency of the second-1 emission spectrum (S2-1). The intensity of the second frequency of the second-2 emission spectrum (S2-2) can be formed to be smaller than the intensity at the first frequency of the first-2 emission spectrum (S1-2).

[0144] The third light-emitting element (200c) can generate light that forms a third light-emitting spectrum (S3). The third light-emitting element (200c) can generate light in which the main peak spectrum is located between 600 nm and 670 nm. In other words, the third light-emitting spectrum (S3) may have a third main peak wavelength located in the red wavelength band. At this time, the third main peak wavelength may be the main peak wavelength in the spectrum excluding auxiliary peaks. In addition, the third main peak wavelength may include multiple peaks. The multiple peaks of the third main peak wavelength may include a third main peak and a third auxiliary peak, but are not limited thereto. For example, the third main peak wavelength of the second light-emitting element (200b) may have a rate of change of frequency according to current density of WD3 as shown in FIG. 23, which will be described later.

[0145] The third main peak can be located between 600 nm and 670 nm. In other words, the third main peak can be located in the red wavelength range. In this case, the dominant wavelength of the third main peak can be located between 600 nm and 670 nm. The dominant wavelength of the third main peak is called the third frequency. The third frequency can be located between the third main peak and the third auxiliary peak. Additionally, the difference between the third auxiliary peak and the third main peak can be less than 15 nm.

[0146] One or more third auxiliary peaks may be formed in the third spectrum. These third auxiliary peaks may be located in wavelength bands different from the third main peak. In other words, one or more third auxiliary peaks may be located in wavelength bands other than the red wavelength region. For example, the third auxiliary peaks may be located in the blue wavelength region band or the green wavelength region band.

[0147] Additionally, the third emission spectrum (S3) may change according to the current density supplied to the third emission element (200c). Depending on the current density, the third emission spectrum (S3) may be formed into a third-1 emission spectrum (S3-1) and a third-2 emission spectrum (S3-2).

[0148] The third-1 emission spectrum (S3-1) can be formed by light generated from the third emission element (200c) when the current density supplied to the third emission element (200c) is greater than the current density supplied to the third emission element (200c) to form the third-2 emission spectrum (S3-2). The wavelength of the third frequency of the third-1 emission spectrum (S3-1) may be smaller than the wavelength of the third frequency of the third-2 emission spectrum (S3-2). Additionally, the intensity at the third frequency of the third-1 emission spectrum (S3-1) may be greater than the intensity at the third frequency of the third-2 emission spectrum (S3-2).

[0149] The third-2 emission spectrum (S3-2) can be formed by light generated from the third emission element (200c) when the current density supplied to the third emission element (200c) is smaller than the current density supplied to the third emission element (200c) to form the third-1 emission spectrum (S2-1). The wavelength of the third frequency of the third-2 emission spectrum (S3-2) may be greater than the wavelength of the third frequency of the third-1 emission spectrum (S3-1). Additionally, the intensity at the third frequency of the third-2 emission spectrum (S3-2) may be smaller than the intensity at the third frequency of the third-1 emission spectrum (S3-1).

[0150] The controller (300) can control the current so that the current density supplied to the plurality of light-emitting elements (200) changes over time. By this controller (300), each of the plurality of light-emitting elements (200) can generate light of different frequencies. In addition, by the controller (300), the light-emitting device (1) can generate light having a light emission spectrum in the white wavelength band in a certain time interval by means of the current changing over time. The light-emitting device (1) can be driven by a Pulse Width Modulation (PWM) method. The frequency of the current can be 60 Hz or higher. The color of the light generated by this light-emitting device (1) can be continuously visible to the user.

[0151] When a current whose magnitude changes for a predetermined time is supplied to a plurality of light-emitting elements (200) by a controller (300), the light emission spectra of the plurality of light-emitting elements (200) may overlap at least partially. In other words, an overlapping spectrum (OS) may be formed by overlapping at least partially of the first light emission spectrum (S1), the second light emission spectrum (S2), and the third light emission spectrum (S3).

[0152] The superimposed spectrum (OS) may have a white color temperature. Multiple peaks and valleys may be formed in the superimposed spectrum (OS). The difference between the peaks and valleys of this superimposed spectrum (OS) may be smaller than the difference between the peaks and valleys formed in each of the multiple emission spectra. Through this superimposed spectrum (OS), the light-emitting device (1) can improve the CRI and generate light similar to sunlight. The color rendering index (CRI) of the superimposed spectrum (OS) may have a value of Ra 70 or higher. The superimposed spectrum (OS) may satisfy Rf 70 or higher in the color fidelity category, which evaluates the degree of similarity to sunlight. More preferably, the color rendering index (CRI) of the superimposed spectrum (OS) may have a value of Ra 80 or higher. The superimposed spectrum (OS) may satisfy Rf 80 or higher in the color fidelity category, which evaluates the degree of similarity to sunlight.

[0153] A light-emitting device (1) according to the fourth embodiment of the present invention will be described below with reference to FIG. 13.

[0154] The light-emitting device (1) according to the fourth embodiment of the present invention differs in that, in order to improve the color rendering index (CRI) of the superposition spectrum (OS), one or more of the first light-emitting element (200a), the second light-emitting element (200b), and the third light-emitting element (200c) may include one or more light-emitting parts, and this difference will be explained mainly.

[0155] The first light-emitting element (200a) may include a first-1 light-emitting part (200a-1) and a first-2 light-emitting part (200a-2). The first-1 light-emitting part (200a-1) and the first-2 light-emitting part (200a-2) may have different first frequencies. For example, when the first-1 light-emitting part (200a-1) emits a first-1 light-emitting spectrum (S1-1), the first-2 light-emitting part (200a-2) may emit a first-2 light-emitting spectrum (S1-2). That is, the first-2 light-emitting part (200a-2) may have a first frequency that is longer than the first frequency of the first-1 light-emitting part (200a-1).

[0156] The first-1 light-emitting unit (200a-1) can be driven at a higher current density than the first-2 light-emitting unit (200a-2). Through this, the first-2 light-emitting unit (200a-2) can have a first frequency of a first longer wavelength than the first-1 light-emitting unit (200a-1). At this time, the controller (300) can adjust the amount of current so that the first-2 light-emitting unit (200a-2) is driven at a lower current density than the first-1 light-emitting unit (200a-1).

[0157] The second light-emitting element (200b) may include a second-1 light-emitting part (200b-1) and a second-2 light-emitting part (200b-2). In this case, the second-1 light-emitting part (200b-1) and the second-2 light-emitting part (200b-2) may have different second frequencies. For example, when the second-1 light-emitting part (200b-1) emits a second-1 light-emitting spectrum (S2-1), the second-2 light-emitting part (200b-2) may emit a second-2 light-emitting spectrum (S2-2). That is, the second-2 light-emitting part (200b-2) may have a second frequency that is longer than the second frequency of the second-1 light-emitting part (200b-1).

[0158] At this time, the second-1 light-emitting unit (200b-1) can be driven with a higher current density than the second-2 light-emitting unit (200b-2). Through this, the second-2 light-emitting unit (200b-2) can have a second wavelength that is longer than the second wavelength of the second-1 light-emitting unit (200b-1). At this time, the controller (300) can adjust the amount of current so that the second-2 light-emitting unit (200b-2) is driven with a lower current density than the second-1 light-emitting unit (200b-1).

[0159] Additionally, the third light-emitting element (200b) may include a third-1 light-emitting part (200c-1) and a third-2 light-emitting part (200c-2). In this case, the third-1 light-emitting part (200c-1) and the third-2 light-emitting part (200c-2) may have different third frequencies. For example, when the third-1 light-emitting part (200c-1) emits a third-1 light-emitting spectrum (S3-1), the third-2 light-emitting part (200c-2) may emit a third-2 light-emitting spectrum (S3-2). That is, the third-2 light-emitting part (200c-2) may have a third frequency that is longer than the third frequency of the third-1 light-emitting part (200c-1).

[0160] At this time, the third-1 light-emitting unit (200c-1) can be driven at a higher current density than the third-2 light-emitting unit (200c-2). Through this, the third-2 light-emitting unit (200c-2) can have a longer wavelength than the third-1 light-emitting unit (200c-1). At this time, the controller (300) can adjust the amount of current so that the third-2 light-emitting unit (200c-2) is driven at a lower current density than the third-1 light-emitting unit (200c-1).

[0161] Hereinafter, with reference to FIG. 14, a first example in which a controller (300) supplies a first current waveform to one or more of a plurality of light-emitting elements (200) will be described.

[0162] The controller (300) can control the current so that a first current waveform, whose magnitude decreases over time, is supplied to a plurality of light-emitting elements (200). The controller (300) can supply the first current waveform for a predetermined current supply time. The current supply time may include a plurality of time intervals having different start time values. The plurality of time intervals may have a longer time length as the time interval with a larger start time value. Additionally, the controller (300) can form the first current waveform by controlling the current so that the current supplied to the plurality of light-emitting elements (200) decreases as the time interval with a larger start time value increases.

[0163] For example, a plurality of time intervals may include a first time interval (t1), a second time interval (t2), a third time interval (t3), a fourth time interval (t4), a fifth time interval (t5), a sixth time interval (t6), and a seventh time interval (t7). The starting time value of the first time interval (t1) may be the smallest among the plurality of time intervals. The first time length of the first time interval (t1) may be the shortest among the plurality of time intervals. The starting time value of the seventh time interval (t7) may be the largest among the plurality of time intervals. The second time length of the seventh time interval (t7) may be the longest among the plurality of time intervals. In this first time interval (t1), the largest first current value among the plurality of time intervals may be supplied to the plurality of light-emitting elements (200) during the shortest time among the plurality of time intervals. In the seventh time interval (t7), the smallest second current value can be supplied to the plurality of light-emitting elements (200) for the longest time among the plurality of time intervals. Additionally, the amount of electricity or charge supplied in the first time interval (t1) and the seventh time interval (t7) may be similar. The amount of electricity may be the value obtained by multiplying the time length and the current intensity value. In other words, since the light-emitting energy can be maintained even if the intensity of the current supplied to the plurality of light-emitting elements (200) decreases as time passes, the amount of light produced per hour by the light-emitting device (1) can be maintained. For example, even if the current decreases and the spectrum of light generated by the light-emitting device (1) is formed as a long wavelength, the light-emitting energy of the light-emitting device (1) can be maintained at a constant level by increasing the current supply time to the light-emitting device (1).

[0164] The difference in electric quantity between the first time interval (t1) and the seventh time interval (t7) may be less than 10%. The ratio of the first time length of the first time interval (t1) to the current supplied to the first time interval (t1) may be similar to the ratio of the second time length of the seventh time interval (t7) to the current supplied to the seventh time interval (t7), and the difference may be less than 10%. The duty of the current may vary by interval. As the magnitude of the current decreases, the duty increases, and brightness may be maintained. In addition, the ratio of the decrease in current from the first time interval (t1) to the seventh time interval (t7) may be similar to the ratio of the increase in time length from the first time interval (t1) to the seventh time interval (t7), and the difference may be less than 10%. The ratio between the first time length and the first current value and the ratio between the first time length and the second current value are similar to each other, and the difference may be less than 10%. Through this, the luminous energy of the light-emitting device (1) can be maintained at a constant level even with changes in the time interval.

[0165] In addition, the first current value, the first time length, the second current value, and the second time length can satisfy the following mathematical formula 1.

[0166] [Mathematical Formula 1]

[0167]

[0168] Additionally, in the first time interval (t1), light forming a first-1 emission spectrum (S1-1), a second-1 emission spectrum (S2-1), or a third-1 emission spectrum (S3-1) may be generated from the light-emitting element (200).

[0169] In the seventh time interval (t7), light forming the first-2 emission spectrum (S1-2), the second-2 emission spectrum (S2-2), or the third-2 emission spectrum (S3-2) can be generated from the light-emitting element (200).

[0170] The electric quantity in one or more of the second time interval (t2), third time interval (t3), fourth time interval (t4), fifth time interval (t5), and sixth time interval (t6) located between the first time interval (t1) and the seventh time interval (t7) may be similar to the electric quantity in the first time interval (t1) and the seventh time interval (t7). The difference may be less than 10%. Through such a small rectification difference, the wavelength overlap region can be widened to increase the color reproduction rate. The following description is based on the second time interval (t2), but is not limited thereto.

[0171] In the second time interval (t2), light forming an emission spectrum between the first-1 emission spectrum (S1-1) and the first-2 emission spectrum (S1-2), an emission spectrum between the second-1 emission spectrum (S2-1) and the second-2 emission spectrum (S2-2), or an emission spectrum between the third-1 emission spectrum (S3-1) and the third-2 emission spectrum (S3-2) can be generated from the light-emitting element (200). Through this, the spectra changing for each time interval are superimposed to emit white light.

[0172] Meanwhile, the first current waveform may be in a continuous form, but is not limited thereto. The first current waveform may be supplied to the light-emitting element (200) discontinuously. This allows for saving power consumption. Additionally, the first current waveform may be formed to have a constant current value over a time interval, but is not limited thereto. In other words, the controller (300) may control the current so that the current decreases as time passes within at least some of the multiple starting intervals. In this case, the duty cycle of the first current waveform may be 60Hz or higher. This allows for the absence of flickering and enables the superposition of wavelengths.

[0173] Hereinafter, with reference to FIG. 15, a second example in which a controller (300) supplies a second current waveform to one or more of a plurality of light-emitting elements (200) will be described.

[0174] The controller (300) can control the current so that a second current waveform, whose magnitude increases over time, is supplied to a plurality of light-emitting elements (200). The controller (300) can supply the second current waveform for a predetermined current supply time. The current supply time may include a plurality of time intervals having different start time values. The plurality of time intervals may have a shorter time length as the time interval with a larger start time value increases. Additionally, the controller (300) can form the second current waveform by controlling the current so that the current supplied to the plurality of light-emitting elements (200) increases as the time interval with a larger start time value increases.

[0175] For example, a plurality of time intervals may include a first time interval (t1), a second time interval (t2), a third time interval (t3), a fourth time interval (t4), a fifth time interval (t5), a sixth time interval (t6), and a seventh time interval (t7). The starting time value of the first time interval (t1) may be the smallest among the plurality of time intervals. The first time length of the first time interval (t1) may be the longest among the plurality of time intervals. The starting time value of the seventh time interval (t7) may be the largest among the plurality of time intervals. The second time length of the seventh time interval (t7) may be the shortest among the plurality of time intervals. In this first time interval (t1), the smallest first current value may be supplied to the plurality of light-emitting elements (200) during the longest time among the plurality of time intervals. In the seventh time interval (t7), a large second current value can be supplied to the plurality of light-emitting elements (200) during the shortest time among the plurality of time intervals. Additionally, the amount of electricity supplied in the first time interval (t1) and the seventh time interval (t7) may be similar. In other words, even if the current supplied to the plurality of light-emitting elements (200) increases as time passes, the light-emitting energy can be maintained, so the amount of light produced per hour by the light-emitting device (1) can be maintained. That is, even if the current is controlled and the spectrum of light generated by the light-emitting device (1) is formed as a short wavelength, the light-emitting energy of the light-emitting device (1) can be maintained at a constant level.

[0176] The difference in electric quantity between the first time interval (t1) and the seventh time interval (t7) may be less than 10%. The ratio of the first time length of the first time interval (t1) to the current supplied to the first time interval (t1) may be similar to the ratio of the second time length of the seventh time interval (t7) to the current supplied to the seventh time interval (t7), and the difference may be less than 10%. The duty of the current may vary by interval. As the magnitude of the current increases, the duty may decrease so that brightness can be maintained. In addition, the ratio of the increase in current from the first time interval (t1) to the seventh time interval (t7) may be similar to the ratio of the decrease in time length from the first time interval (t1) to the seventh time interval (t7), and the difference may be less than 10%. The ratio between the first time length and the first current value and the ratio between the first time length and the second current value are similar to each other, and the difference may be less than 10%.

[0177] In addition, the first current value, the first time length, the second current value, and the second time length can satisfy the following mathematical formula 2.

[0178] [Mathematical Formula 2]

[0179]

[0180] In the first time interval (t1), a first-2 emission spectrum (S1-2), a second-2 emission spectrum (S2-2), or a third-2 emission spectrum (S3-2) may be generated in the light-emitting element (200).

[0181] In the seventh time interval (t7), light forming the first-1 emission spectrum (S1-1), the second-1 emission spectrum (S2-1), or the third-1 emission spectrum (S3-1) may be generated from the light-emitting element (200).

[0182] The electric quantity in one or more of the second time interval (t2), third time interval (t3), fourth time interval (t4), fifth time interval (t5), and sixth time interval (t6) located between the first time interval (t1) and the seventh time interval (t7) may be similar to the electric quantity in the first time interval (t1) and the seventh time interval (t7), and the difference may be less than 10%. The following description is based on the second time interval (t2), but is not limited thereto.

[0183] In the second time interval (t2), light forming a light emission spectrum between the first-1 emission spectrum (S1-1) and the first-2 emission spectrum (S1-2), a light emission spectrum between the second-1 emission spectrum (S2-1) and the second-2 emission spectrum (S2-2), or a light emission spectrum between the third-1 emission spectrum (S3-1) and the third-2 emission spectrum (S3-2) may be generated from the light-emitting element (200).

[0184] Meanwhile, the second current waveform may be in a continuous form, but is not limited thereto. The second current waveform may be supplied to the light-emitting element (200) discontinuously. Since the light-emitting element (200) can be driven discontinuously by the second current waveform, driving energy can be saved.

[0185] Hereinafter, with reference to FIG. 16, a third example in which a controller (300) supplies a third current waveform to one or more of a plurality of light-emitting elements (200) will be described.

[0186] The controller (300) can control the current so that a third current waveform is supplied to the multiple light-emitting elements (200) such that the amount of electricity supplied to the multiple light-emitting elements (200) increases over time. The controller (300) can control the current so that the magnitude of the current increases even within multiple time intervals. By this controller (300), the wavelength of the light-emitting device (1) can be controlled while the light-emitting energy is maintained at a constant level. The amount of electricity in the first time interval (t1), where the lowest first current value is supplied, and the amount of electricity in the seventh time interval (t7), where the highest second current value is supplied, are similar to each other, and the difference between them may be less than 10%. Through this, a natural color change can be realized. The rate of change of current in the first time interval (t1) may be smaller than the rate of change of current in the seventh time interval (t7). In other words, the third current waveform can be formed to have different slopes in multiple time intervals. The slope of the current in multiple time intervals may have the lowest slope in the first time interval (t1) and the highest slope in the seventh time interval (t7). The center of the slope of the current in each of the multiple time intervals may coincide with the center of the time length of each of the multiple time intervals. Additionally, the current value at the start time value of the first time interval (t1) may be smaller than the current value at the end time value of the first time interval (t1). The average of the currents at the start time value and the end time value of the first time interval (t1) may be equal to the current value at the center of the first time length.

[0187] The ratio of the first time length of the first time interval (t1) to the current supplied to the first time interval (t1) may be similar to the ratio of the second time length of the seventh time interval (t7) to the current supplied to the seventh time interval (t7), and the difference may be less than 10%. The duty of the current may vary by interval. As the current decreases, the duty increases so that brightness can be maintained. In addition, the ratio of the increase in current from the first time interval (t1) to the seventh time interval (t7) may be similar to the ratio of the decrease in time length from the first time interval (t1) to the seventh time interval (t7), and the difference may be less than 10%. Natural color control is possible by managing the decrease in each interval to be less than 10%.

[0188] In the first time interval (t1), light forming a light emission spectrum between the first-1 emission spectrum (S1-1) and the first-2 emission spectrum (S1-2), a light emission spectrum between the second-1 emission spectrum (S2-1) and the second-2 emission spectrum (S2-2), or a light emission spectrum between the third-1 emission spectrum (S3-1) and the third-2 emission spectrum (S3-2) can be generated from the light-emitting element (200).

[0189] Additionally, in the seventh time interval (t7), light forming a light emission spectrum between the first-1 emission spectrum (S1-1) and the first-2 emission spectrum (S1-2), a light emission spectrum between the second-1 emission spectrum (S2-1) and the second-2 emission spectrum (S2-2), or a light emission spectrum between the third-1 emission spectrum (S3-1) and the third-2 emission spectrum (S3-2) may be generated from the light-emitting element (200).

[0190] The emission spectrum of light generated in the first time interval (t1) can be positioned closer to the first-1 emission spectrum (S1-1), the second-1 emission spectrum (S2-1), or the third-1 emission spectrum (S3-1) than the emission spectrum of light generated in the seventh time interval (t7).

[0191] Meanwhile, the third current waveform is expressed in a continuous form, but is not limited thereto. The third current waveform can be supplied to the light-emitting element (200) discontinuously. Since the light-emitting element (200) can be driven discontinuously by the third current waveform, power consumption can be saved.

[0192] The controller (300) can control the supply of different current waveforms to a plurality of light-emitting elements (200). For example, the controller (400) can control the supply of a first current waveform to a first light-emitting element (200a) and a second current waveform or a third current waveform to a second light-emitting element (200b). Since these plurality of light-emitting elements (200) can receive different current waveforms during the current supply time to form light of an overlapping spectrum, white light with improved CRI can be realized.

[0193] Hereinafter, with reference to FIG. 17, a fourth example is described in which the controller (300) supplies a fourth current waveform to the first light-emitting element (200a) and supplies a fifth current waveform to the second light-emitting element (200c).

[0194] The fourth current waveform can be formed so that current is supplied to the first light-emitting element (200a) at a preset first current supply cycle. The fifth current waveform can be formed so that current is supplied to the second light-emitting element (200b) at a predetermined second current supply cycle.

[0195] Additionally, the time during which current is supplied in the first current supply cycle may be shorter than the time during which current is supplied in the second current supply cycle. Also, the magnitude of the current in the first current supply cycle may be formed to be larger than the current supplied in the second current supply cycle.

[0196] This first light-emitting element (200a) can generate light that forms a first-1 emission spectrum (S1-1), a second-1 emission spectrum (S2-1), and a third-1 emission spectrum (S3-1). Additionally, the second light-emitting element (200b) can generate light that forms a first-2 emission spectrum (S1-2), a second-2 emission spectrum (S2-2), and a third-2 emission spectrum (S3-2). Through this, the emission spectra are efficiently superimposed, which can lower the difficulty of realizing white light.

[0197] Hereinafter, with reference to FIG. 18, a fifth example is described in which a controller (300) supplies a first current waveform to a first light-emitting element (200a) and supplies a second current waveform to a second light-emitting element (200b).

[0198] The current supplied to the first light-emitting element (200a) may decrease in magnitude as time progresses. The current supplied to the second light-emitting element (200b) may increase in magnitude as time progresses. This first light-emitting element (200a) may generate light forming a spectrum among the first-1 emission spectrum (S1-1), the second-1 emission spectrum (S2-1), or the third-1 emission spectrum (S3-1) at the start of operation time. Additionally, the second light-emitting element (200b) may generate light forming at least one spectrum among the first-2 emission spectrum (S1-2), the second-2 emission spectrum (S2-2), or the third-2 emission spectrum (S3-2) at the start of operation time.

[0199] The first light-emitting element (200a) can generate light that forms a spectrum similar to one of the first-2 light-emitting spectrum (S1-2), the second-2 light-emitting spectrum (S2-2), or the third-2 light-emitting spectrum (S3-2) as the driving time progresses. Additionally, the second light-emitting element (200b) can emit a spectrum similar to one of the second-1 light-emitting spectrum (S2-1) or the third-1 light-emitting spectrum (S3-1) as the driving time progresses. In other words, the wavelength of the light generated by the first light-emitting element (200a) can become longer as time progresses, and the wavelength of the light generated by the second light-emitting element (200b) can become shorter as the driving time progresses. The light intensity emitted by the first light-emitting element (200a) can increase as time progresses, and the light intensity of the second light-emitting element (200b) can decrease as time progresses.

[0200] In addition, as the driving time progresses, the difference in light intensity between the first light-emitting element (200a) and the second light-emitting element (200b) may decrease in stages. Furthermore, as the driving time progresses, the difference in light intensity between the first light-emitting element (200a) and the second light-emitting element (200b) may increase in stages.

[0201] White light with an improved CIR value can be realized by these first light-emitting element (200a) and second light-emitting element (200b). Since the electric quantity of the first light-emitting element (200a) and the second light-emitting element (200b) can be the same, the amount of light produced per hour by the first light-emitting element (200a) and the second light-emitting element (200b) can be maintained. That is, the sum of the luminous energy over time emitted by the first light-emitting element (200a) and the second light-emitting element (200b) can be maintained constant by controlling the current.

[0202] Hereinafter, with reference to FIG. 19, a sixth example in which a controller (300) supplies a sixth current waveform to one or more of a plurality of light-emitting elements (200) will be described.

[0203] The controller (300) can control the current so that a sixth current waveform, in which current is supplied at a magnitude of the first current density (J1), is supplied to one of the plurality of light-emitting elements (200). The controller (300) can supply the sixth current waveform for a predetermined driving time. The sixth current waveform is supplied during current supply times (Ta1, Ta3, … Ta 2n +1 It can be driven with the same first current density (J1) during ). At this time, the sixth current waveform may have a first charge density per unit area (C1). The first charge density per unit area (C1) can be expressed by the following Equation 3.

[0204] [Mathematical Formula 3]

[0205]

[0206] The first charge density per unit area (C1) is the current supply time (Ta1, Ta3, … Ta 2n+1 It can be constant during ).

[0207] Hereinafter, with reference to FIG. 20, a seventh example in which a controller (300) supplies a seventh current waveform to one or more of a plurality of light-emitting elements (200) will be described.

[0208] The controller (300) can control the current so that a seventh current waveform, in which current is supplied at a second current density (J2) greater than the first current density (J1) described above, is supplied to one or more of the plurality of light-emitting elements (200). The controller (300) can supply the seventh current waveform for a predetermined driving time. The seventh current waveform is supplied during current supply times (Tb1, Tb3, … Tb 2n+1 It can be driven with the same second current density (J2) during ). At this time, the seventh current waveform may have a second charge density per unit area (C2). The second charge density per unit area (C2) can be expressed by the following Equation 4.

[0209] [Mathematical Formula 4]

[0210]

[0211] The second charge density per unit area (C2) is the current supply time (Tb1, Tb3, … Tb 2n+1 It can be constant during ).

[0212] At this time, the second charge density per unit area (C2) may be similar to the first charge density per unit area (C1). The difference between the first charge density per unit area (C1) and the second charge density per unit area (C2) may be less than 10%. The first charge density per unit area (C1) and the second charge density per unit area (C2) can be expressed by the following mathematical formula 5.

[0213] [Mathematical Formula 5]

[0214]

[0215] Through this, the amount of charge per unit time of the light-emitting element (200) driven by the 6th current waveform and the light-emitting element (200) driven by the 7th current waveform can be the same, so the brightness of the light-emitting element (200) driven by the 6th current waveform and the brightness of the light-emitting element (200) driven by the 7th current waveform can be perceived as the same. If the difference is smaller than 90% or larger than 110%, the brightness is perceived as different, and light uniformity may be reduced.

[0216] The first current density (J1) may be smaller than the second current density (J2). Also, the current supply time (Tb1, Tb3, … Tb) of the seventh current waveform 2n +1 Each of the ) is the current supply time of the 6th current waveform (Ta1, Ta3, … Ta 2n +1 ) It may be shorter than each. Also, the current supply time of the 7th current waveform (Tb1, Tb3, … Tb 2n + 1) and the current supply time of the 6th current waveform (Ta1, Ta3, … Ta 2n + 1) can be expressed as shown in mathematical formula 6 below.

[0217] [Mathematical Formula 6]

[0218]

[0219] Hereinafter, with reference to FIG. 21, an 8th example is described in which a controller (300) supplies an 8th current waveform to one or more of a plurality of light-emitting elements (200).

[0220] The controller (300) can control the current so that an eighth current waveform, with a magnitude of a third current density (J3), is supplied to one or more of the plurality of light-emitting elements (200). The controller (300) can supply the eighth current waveform for a predetermined driving time. The eighth current waveform is supplied during a current supply time (Tc1, Tc3, … Tc 2n + 1) It can be driven with the same third current density (J3) during this period. At this time, the eighth current waveform may have a third charge density per unit area (C3). The third charge density per unit area (C3) can be expressed by the following mathematical formula 7.

[0221] [Mathematical Formula 7]

[0222]

[0223] The third charge density per unit area (C3) is the current supply time (Tc1, Tc3, … Tc 2n+1 It can be constant during ).

[0224] At this time, the third charge density per unit area (C3) may be similar to the second charge density per unit area (C2). At this time, the difference between the second charge density per unit area (C2) and the third charge density per unit area (C3) may be less than 10%. The third charge density per unit area (C3) and the second charge density per unit area (C2) can be expressed as shown in Equation 8 below.

[0225] [Mathematical Formula 8]

[0226]

[0227] Through this, since the charge per unit time of the light-emitting element (200) driven by the 8th current waveform and the light-emitting element (200) driven by the 7th current waveform can be the same, the brightness of the light-emitting element (200) driven by the 7th current waveform and the brightness of the light-emitting element (200) driven by the 8th current waveform can be perceived as the same.

[0228] The third current density (J3) may be greater than the second current density (J2). Also, the current supply time of the eighth current waveform (Tc1, Tc3, … Tc 2n +1 Each of ) is the current supply time of the 7th current waveform (Tb1, Tb3, … Tb 2n + 1) and may be shorter than each. Current supply time of the 8th current waveform (Tc1, Tc3, … Tc 2n+1 ) and the current supply time of the 7th current waveform (Tb1, Tb3, … Tb 2n + 1) can be expressed as shown in mathematical formula 9 below.

[0229] [Mathematical Formula 9]

[0230]

[0231] In addition, the third charge density per unit area (C3) may be similar to the first charge density per unit area (C1). In this case, the difference between the first charge density per unit area (C1) and the third charge density per unit area (C3) may be less than 10%. In this case, the current supply time of the eighth current waveform (Tc1, Tc3, … Tc 2n +1 Each of the ) is the current supply time of the 6th current waveform (Ta1, Ta3, … Ta 2n +1 ) may be shorter than each. Current supply time of the 8th current waveform (Tc1, Tc3, … Tc 2n + 1) and the current supply time of the 6th current waveform (Ta1, Ta3, … Ta 2n+1 ) can be expressed as shown in mathematical formula 10 below.

[0232] [Mathematical Formula 10]

[0233]

[0234] Hereinafter, with reference to FIG. 22, a ninth example is described in which a controller (300) supplies a ninth current waveform to one or more of a plurality of light-emitting elements (200).

[0235] The controller (300) can control the current so that a ninth current waveform, in which the current density changes over time, is supplied to one or more of the plurality of light-emitting elements (200). The controller (300) can supply the ninth current waveform for a predetermined current supply time. The current supply time may include a plurality of time intervals having different start time values. Additionally, the plurality of time intervals may have shorter time lengths as the current density increases. At this time, the area charge density for each interval may be the same. Additionally, the plurality of time intervals may have longer time lengths as the current density decreases. For example, one of the plurality of light-emitting elements (200) may be driven with a first current density (J1) during a first time interval (T1) to have a fourth-first area charge density (C4-1). Additionally, another of the plurality of light-emitting elements (200) may be driven with a second current density (J2) during a third time interval (T3) to have a fourth-third area charge density (C4-3). The fourth-third area charge density (C4-3) may have an area similar to the fourth-first area charge density (C4-1). The difference between the fourth-third area charge density (C4-3) and the fourth-first area charge density (C4-1) may be less than 10%. Through this, the luminous intensity of the light-emitting element (200) can be maintained constant during each time interval. At this time, at least one of the plurality of light-emitting elements (200) may have a repeating charge density. That is, any one of the plurality of light-emitting elements (200) may have a second-n-1 time interval (T 2n-1 During ), it is driven with a first current density (J1) and can have a fourth-first area charge density (C4-1). In addition, another of the plurality of light-emitting elements (200) is driven during a secondn+1 time interval (T2n +1 During this period, it can be driven with a second current density (J2) to have a fourth-third area charge density (C4-3). At this time, the difference between the fourth-first area charge density (C4-1) and the fourth-third area charge density (C4-3) may be less than 10%. The fourth-first area charge density (C4-1) and the fourth-third area charge density (C4-3) can be expressed as shown in Equation 11 below.

[0236] [Mathematical Formula 11]

[0237]

[0238] Additionally, there may be a second time period (T2) between the first time period (T1) and the third time period (T3) during which no current is supplied to the light-emitting element (200). Additionally, there may be a fourth time period (T4) after the third time period (T3) during which no current is supplied to the light-emitting element (200). This allows for a reduction in power consumption. In this case, the second time period (T2) may be shorter than the fourth time period (T4). Furthermore, the sum of the first time period (T1) and the second time period (T2) may be equal to the sum of the time periods of the third time period (T3) and the fourth time period (T4). This allows the driving cycle to be maintained at a constant level, but is not limited thereto.

[0239] In addition, the light-emitting element (200) can be driven at 60 Hz or higher to reduce flicker. In other words, the ninth current waveform can have a cycle that repeats n times during 2n+2 hours. When 2n+2 hours is 60 seconds, it can be repeated a total of 30 times or more. In other words, the 4-1 area charge density (C4-1) and the 4-3 area charge density (C4-3) are each repeated 30 times or more, and the light-emitting element (200) can be lit a total of 60 times or more.

[0240] At this time, the light-emitting element (200) supplied with the ninth current waveform can emit different frequencies for each repeated time interval. For example, during the time interval when the 4-1 area charge density (C4-1) is supplied, it can emit a wavelength longer than during the time interval when the 4-3 area charge density (C4-3) is supplied. For example, during the time interval when the 4-1 area charge density (C4-1) is supplied, it can emit light having a frequency close to the green region, and during the time interval when the 4-3 area charge density (C-3) is supplied, it can emit light having a frequency close to the blue region. Alternatively, during the time interval when the 4-1 area charge density (C4-1) is supplied, it can emit light having a frequency close to the red region, and during the time interval when the 4-3 area charge density (C-3) is supplied, it can emit light having a frequency close to the green region. Through this, the light-emitting element (200) supplied with the ninth current waveform can have a superposition spectrum (OS) with a white color temperature when a certain time interval is repeated.

[0241] Meanwhile, the ninth current waveform is shown as a waveform composed of the first current density (J1) and the second current density (J2), but it is not limited thereto. In addition, multiple light-emitting devices (1) can be driven with multiple different current densities. Even in this case, the area charge density can be maintained constant during the current supply time. Through this, the same light intensity can be maintained even when multiple different current densities are supplied to multiple light-emitting devices (1).

[0242] Hereinafter, with reference to FIG. 23, a light-emitting device (1) according to the fifth embodiment of the present invention will be described.

[0243] In describing the fifth embodiment, there are differences in that it further includes an intermediate layer (211) and an insulating film (212), and that the buffer layer (201) of a plurality of light-emitting elements (200) and the first conductive semiconductor layer (203) are integrally formed, and these differences will be explained in detail.

[0244] The intermediate layer (211) is a layer capable of controlling the movement of carriers distributed within the active region (206). This intermediate layer (211) may be composed of a P / N tunnel junction, a P-Gan, an N-Gan, etc.

[0245] The insulating film (212) can cover the active region (206), the intermediate layer (211), and the second conductive semiconductor layer (208). The insulating film (212) can prevent charge leakage.

[0246] The first light-emitting element (200a) may include a plurality of intermediate layers (211) and a plurality of active regions (206). The plurality of active regions (206) included in the first light-emitting element (200a) may include a first active region (206a), a second active region (206b), and a third active region (206c). The plurality of intermediate layers (211) included in the first light-emitting element (200a) may include a first intermediate layer (211a) and a second intermediate layer (211b).

[0247] A first intermediate layer (211a) may be disposed between a first active region (206a) and a second active region (206b). A second intermediate layer (211b) may be disposed between a second active region (206b) and a third active region (206c). A first active region (206a) may be disposed between a first intermediate layer (211a) and a first conductive semiconductor layer (203). A third active region (206c) may be disposed between a second intermediate layer (211b) and a second conductive semiconductor layer (208). A second active region (206b) may be disposed between a first intermediate layer (211a) and a second intermediate layer (211b). Such a first light-emitting element (200a) may generate light of different frequencies. In other words, the first light-emitting element (200a) can generate white light mixed with blue light, green light, and red light.

[0248] The second light-emitting element (200b) may include one intermediate layer (211) and a plurality of active regions (206). The plurality of active regions (206) included in the second light-emitting element (200b) may include a first active region (206a) and a second active region (206b). The intermediate layer (211) may be disposed between the first active region (206a) and the second active region (206b). The first active region (206a) may be disposed between the first conductive semiconductor layer (203) and the intermediate layer (211). The second active region (206b) may be disposed between the intermediate layer (211) and the second conductive semiconductor layer (208). Such a second light-emitting element (200b) may generate light of different frequencies. In other words, the second light-emitting element (200b) can generate light that is a mixture of blue light and green light.

[0249] The third light-emitting element (200c) may include one active region (206). The active region (206) may be the first active region (206a). This third light-emitting element (200c) may emit blue light.

[0250] Hereinafter, with reference to FIG. 24, a light-emitting device (1) according to the 6th embodiment of the present invention will be described.

[0251] In describing the fifth embodiment, there is a difference in that the second conductivity type semiconductor layer (208) of a plurality of light-emitting elements (200) is stacked on the buffer layer (201) and formed integrally, and this difference will be explained mainly.

[0252] The first light-emitting element (200a) may include a plurality of intermediate layers (211) and a plurality of active regions (206). The plurality of active regions (206) included in the first light-emitting element (200a) may include a first active region (206a), a second active region (206b), and a third active region (206c). The plurality of intermediate layers (211) included in the first light-emitting element (200a) may include a first intermediate layer (211a) and a second intermediate layer (211b). The first intermediate layer (211a) may be disposed between the third active region (206c) and the second active region (206b). The second intermediate layer (211b) may be disposed between the second active region (206b) and the first active region (206a). A first active region (206a) may be disposed between a second intermediate layer (211b) and a first conductive semiconductor layer (203). A third active region (206c) may be disposed between a first intermediate layer (211a) and a second conductive semiconductor layer (208). A second active region (206b) may be disposed between a first intermediate layer (211a) and a second intermediate layer (211b). Such a first light-emitting element (200a) may generate light of different frequencies. In other words, the first light-emitting element (200a) may generate white light that is a mixture of red light, green light, and blue light.

[0253] The second light-emitting element (200b) may include one intermediate layer (211) and a plurality of active regions (206). The plurality of active regions (206) included in the second light-emitting element (200b) may include a third active region (206c) and a second active region (206b). The intermediate layer (211) may be disposed between the third active region (206c) and the second active region (206b). The third active region (206c) may be disposed between the second conductive semiconductor layer (208) and the intermediate layer (211). The second active region (206b) may be disposed between the intermediate layer (211) and the first conductive semiconductor layer (203). Such a second light-emitting element (200b) may generate light of different frequencies. In other words, the second light-emitting element (200b) can generate light that is a mixture of red light and green light.

[0254] The third light-emitting element (200c) may include one active region (206). The active region (206) may be a third active region (206c). This third light-emitting element (200c) may emit red light.

[0255] Hereinafter, a light-emitting device (1) according to the seventh embodiment of the present invention will be described with reference to FIG. 25.

[0256] In describing the sixth embodiment, there is a difference in that the plurality of light-emitting elements (200) further include a third electrode (210c) and a fourth electrode (210d), and this difference will be explained in detail.

[0257] The first light-emitting element (200a) may include a first electrode (210a), a second electrode (210b), a third electrode (210c), and a fourth electrode (210d).

[0258] The third electrode (210c) can be electrically connected to the first intermediate layer (211a). The third electrode (210c) can be electrically connected to the first active region (206a) through the first intermediate layer (211a). Additionally, the third electrode (210c) can be electrically connected to a second conductive semiconductor layer disposed on top of the first active region (206a). A portion of the first intermediate layer (211a) can serve as the second conductive semiconductor layer of the first active region (206a). When a negative electrode and a positive electrode are connected to the first electrode (210b) and the third electrode (210c), respectively, electrons and holes recombine in the first active region (206a) to emit photons and emit light.

[0259] Additionally, the third electrode (210c) can be electrically connected to the second active region (206b) through the first intermediate layer (211a). The third electrode (210c) can be electrically connected to a first conductive semiconductor layer placed below the second active region (206b). A portion of the first intermediate layer (211a) can serve as the first conductive semiconductor layer for the second active region (206b). When the negative electrode and the positive electrode are connected to the third electrode (210c) and the fourth electrode (210d), respectively, electrons and holes recombine in the second active region (206b) to emit photons and light. Furthermore, when the negative electrode and the positive electrode are connected to the fourth electrode (210d) and the second electrode (210b), respectively, electrons and holes recombine in the second active region (206b) and the first active region (206a) to emit photons and light. Through this, a spectrum in which the spectrum of the second active region (206b) and the spectrum of the first active region (206a) are mixed can be obtained. The first intermediate layer (211a) or the second intermediate layer (211b) may be a PN tunnel junction.

[0260] Additionally, the third active region (206c) can be electrically connected through the fourth electrode (210d). The fourth electrode (210d) can be electrically connected to the first conductive semiconductor layer placed below the third active region (206c). A portion of the second intermediate layer (211b) can serve as the first conductive semiconductor layer for the third active region (206c). When the positive and negative electrodes are connected to the fourth electrode (210d) and the first electrode (210a), respectively, electrons and holes recombine in the third active region (206c) to emit photons and light. Furthermore, when the positive and negative electrodes are connected to the first electrode (210a) and the third electrode (210c), respectively, electrons and holes recombine in the third active layer (206c) and the second active layer (206b) to emit photons and light. Through this, a spectrum in which the spectrum of the second active region (206b) and the spectrum of the third active region (206c) are mixed can be obtained. Additionally, when an anode and a cathode are connected to the first electrode (210a) and the second electrode (210b), respectively, electrons and holes recombine in the third active region (206c), the second active region (206b), and the first active layer (206a), thereby emitting photons and light. Through this, a spectrum in which the spectrum of the second active region (206b) and the spectrum of the second active region (206b) and the spectrum of the first active region (206a) are mixed can be obtained.

[0261] Through this electrode connection, the first light-emitting element (200a) can generate one or more of blue light, green light, or red light.

[0262] As a first example, the first light-emitting element (200a) can generate white light mixed with blue light, green light, and red light. As a second example, the first light-emitting element (200a) can generate light mixed with some of blue light, green light, and red light. As a third example, the first light-emitting element (200a) can generate light of any one of blue light, green light, or red light.

[0263] Hereinafter, with reference to FIG. 26, a light-emitting device (1) according to the eighth embodiment of the present invention will be described.

[0264] In describing the eighth embodiment, there is a difference in that the light-emitting element (200) includes a third electrode (210c), and this difference will be explained in detail.

[0265] The second light-emitting element (200b) may include a first electrode (210a), a second electrode (210b), and a third electrode (210c).

[0266] The third electrode (210c) can be electrically connected to the intermediate layer (211). Through this third electrode (210c), the first light-emitting element (200a) can generate one or more of blue light and green light.

[0267] As a first example, the second light-emitting element (200b) can generate light that is a mixture of blue light and green light. As a second example, the second light-emitting element (200b) can generate light that is either blue light or green light.

[0268] Hereinafter, with reference to FIG. 27, it will be explained that controlling the current density supplied to the light-emitting element (200) changes the spectrum of light emitted from the light-emitting element (200), specifically the main wavelength.

[0269] If the current density increases, the frequency of the light-emitting element (200) can be shortened. For example, the controller (300) may be a driving element or a driving circuit that controls the magnitude of the current and the current supply time supplied to a plurality of light-emitting elements (200) placed on the substrate (100). By changing the current density supplied by this controller (300), the frequency of the light-emitting element (200) can be changed. In addition, as shown in FIG. 28 to be described later, the area of ​​the light-emitting element (200) can be different so that the frequency emitted from each light-emitting element (200) can be different.

[0270] In addition, the longer the wavelength, the greater the rate of change of wavelength according to current density. For example, WD1 may be a graph of the rate of change of wavelength according to current density of a light-emitting element (200) having a shorter wavelength than WD2. WD1 may be a graph of the rate of change of wavelength according to current density of a light-emitting element (200) having a shorter wavelength than WD3. WD2 may be a graph of the rate of change of wavelength according to current density of a light-emitting element (200) having a wavelength in the region between WD1 and WD3.

[0271] For example, if the frequency emitted from one of the plurality of light-emitting elements (200) has a rate of change of WD1 and the frequency emitted from another of the plurality of light-emitting elements (200) has a rate of change of WD2, then one of the plurality of light-emitting elements (200) may have an active layer with a higher Al content than the other of the plurality of light-emitting elements (200).

[0272] As another example, if the frequency emitted from one of the plurality of light-emitting elements (200) has a rate of change of WD1 and the frequency emitted from another of the plurality of light-emitting elements (200) has a rate of change of WD3, the other of the plurality of light-emitting elements (200) may have an active layer with a higher In content than any of the plurality of light-emitting elements (200). Additionally, the active layer of the light-emitting element (200) emitting a frequency having a rate of change of WD2 may have an intermediate value of the Al content of the active layer included in the light-emitting element (200) emitting a frequency having a rate of change of WD1. Additionally, the active layer of the light-emitting element (200) emitting a frequency having a rate of change of WD2 may have an intermediate value of the In content of the active layer included in the light-emitting element (200) emitting a frequency having a rate of change of WD3.

[0273] For example, WD1 may be a graph showing the rate of change of frequency according to current density of a light-emitting element (200) having a frequency in the blue wavelength region. WD2 may be a graph showing the change of frequency according to current density of a light-emitting element (200) having a frequency in the green wavelength region. WD3 may be a graph showing the change of frequency according to current density of a light-emitting element (200) having a frequency in the red wavelength region.

[0274] Hereinafter, the ninth embodiment of the present invention will be described with reference to FIG. 28. In describing the ninth embodiment, there is a difference in that at least some of the areas of the plurality of light-emitting elements (200) can be formed differently from one another so that the current value is changed, and this difference will be explained mainly.

[0275] Even if the same current is supplied to multiple light-emitting elements (200a, 200b, 200c), if the areas are formed differently, the multiple light-emitting elements (200a, 200b, 200c) may have different current densities. Through this, the multiple light-emitting elements (200a, 200b, 200c) may emit different frequencies.

[0276] If a first light-emitting element (200a), a second light-emitting element (200b), and a third light-emitting element (300b) are formed in multiple numbers and different current densities are supplied to the multiple light-emitting elements (200a, 200b, 200c), the color reproduction rate of the superposition spectrum (OS) can be increased.

[0277] The first light-emitting element (200a) may have a larger area than the second light-emitting element (200b). Through this, the first light-emitting element (200a) may have a smaller current density than the second light-emitting element (200b). The wavelength of the first light-emitting element (200a) may be longer than the wavelength of the second light-emitting element (200b). For example, the first light-emitting element (200a) may have a wavelength closer to the red wavelength region than the second light-emitting element (200b).

[0278] The first short axis (a1) of the first light-emitting element (200a) may be larger than the second short axis (a2) of the second light-emitting element (200b), and the first long axis (b1) of the first light-emitting element (200a) may be equal to the second long axis (b2) of the second light-emitting element (200b), but is not limited thereto. In other words, the first long axis (b1) of the first light-emitting element (200a) may be larger than the second long axis (b2) of the second light-emitting element (200b), and the first short axis (a1) of the first light-emitting element (200a) and the second short axis (a2) of the second light-emitting element (200b) may have the same length. Additionally, the first major axis (b1) and the first minor axis (a1) of the first light-emitting element (200a) may be larger than the second major axis (b2) and the second minor axis (a2) of the second light-emitting element (200b). Through this, the area of ​​the first light-emitting element (200a) may be larger than the area of ​​the second light-emitting element (200b). The height of the first light-emitting element (200a) may be similar to the height of the second light-emitting element (200b). The difference in height between the first light-emitting element (200a) and the second light-emitting element (200b) may be less than 10%.

[0279] The second light-emitting element (200b) may have a larger area than the third light-emitting element (200c). Through this, the second light-emitting element (200b) may have a smaller current density than the third light-emitting element (200c). Additionally, the frequency of the second light-emitting element (200b) may have a longer wavelength than the frequency of the third light-emitting element (200c). For example, the second light-emitting element (200b) may have a frequency closer to the green wavelength region than the third light-emitting element (200c). The third light-emitting element (200c) may have the smallest light-emitting area among the plurality of light-emitting elements (200a, 200b, 200c). Additionally, the third light-emitting element (200c) may have the largest current density among the plurality of light-emitting elements (200a, 200b, 200c). The third light-emitting element (200c) may have a frequency close to the blue region.

[0280] The second short axis (a2) of the second light-emitting element (200b) may be larger than the third short axis (a3) ​​of the third light-emitting element (200c), and the second long axis (b2) of the second light-emitting element (200c) and the third long axis (b3) of the third light-emitting element (200c) may be the same, but are not limited thereto. In other words, the second long axis (b2) of the second light-emitting element (200a) may be larger than the third long axis (b3) of the third light-emitting element (200c), and the second short axis (a2) of the second light-emitting element (200a) may have the same length as the third short axis (a3) ​​of the third light-emitting element (200c). Additionally, the second major axis (b2) and the second minor axis (a2) of the second light-emitting element (200b) may be larger than the third major axis (b3) and the third minor axis (a3) ​​of the third light-emitting element (200c). Through this, the area of ​​the second light-emitting element (200c) may be larger than the area of ​​the third light-emitting element (200c). The height of the second light-emitting element (200c) may be similar to the height of the third light-emitting element (200c). The difference in height between the second light-emitting element (200c) and the third light-emitting element (200c) may be less than 10%.

[0281] In addition, to maintain a constant luminous flux in multiple light-emitting elements (200a, 200b, 200c) having different areas, the time for which current is applied to each light-emitting element (200a, 200b, 200c) can be varied. Therefore, the area charge density during the driving time of each light-emitting element (200a, 200b, 200c) may be similar to each other. For example, the first light-emitting element (200a) may have a shorter driving time interval than the second light-emitting element (200b). Also, the second light-emitting element (200b) may have a shorter driving time interval than the third light-emitting element (200c). Also, the third light-emitting element (200c) may have the narrowest light-emitting area. In addition, the third light-emitting element (200c) may have the largest current density among the light-emitting elements (200a, 200b, 200c). The third light-emitting element (200c) may have a frequency close to the blue region.

[0282] Meanwhile, the operation of the plurality of light-emitting elements (200) may be similar to the operation of the first to ninth embodiments, thereby increasing the color reproduction rate of the light-emitting device (1).

[0283] FIG. 29 is a diagram showing another embodiment of an overlapping spectrum (OS) in which a plurality of emission spectra (S1, S2, S3) are superimposed.

[0284] Referring to FIG. 29, the superposition spectrum (OS) obtained by driving a plurality of light-emitting elements (200) for a certain period of time may have a white spectrum similar to sunlight (RF). A plurality of peaks and valleys may be formed in the superposition spectrum (OS).

[0285] To realize a white spectrum similar to sunlight (RF), at least one of the first light-emitting element (200a), the second light-emitting element (200b), and the third light-emitting element (200c) may include one or more light-emitting parts. Unlike FIG. 12, the time-dependent overlap intensity of the first-1 light-emitting spectrum (S1-1), the second-1 light-emitting spectrum (S2-1), and the third-1 light-emitting spectrum (S3-1) may be lower than the overlap intensity of the first-2 light-emitting spectrum (S1-2), the second-2 light-emitting spectrum (S2-2), and the third-2 light-emitting spectrum (S3-2). To this end, the application time of the current density applied to a plurality of light-emitting elements (200) to emit a first-2 emission spectrum (S1-2), a second-2 emission spectrum (S2-2), and a third-2 emission spectrum (S3-2) may be longer than the application time of the current density applied to emit a first-1 emission spectrum (S1-1), a second-1 emission spectrum (S2-1), and a third-1 emission spectrum (S3-1).

[0286] Although the embodiments of the present invention have been described above as specific embodiments, they are merely examples and the present invention is not limited thereto, but should be interpreted as having the broadest scope in accordance with the technical concept disclosed in this specification. Those skilled in the art may implement patterns of shapes not specified by combining or substituting the disclosed embodiments, and this also does not deviate from the scope of the present invention. Furthermore, those skilled in the art may easily modify or alter the disclosed embodiments based on this specification, and it is evident that such modifications or alterations also fall within the scope of the rights of the present invention.

Claims

1. Substrate; A first light-emitting element disposed on the substrate and generating light of a first emission spectrum having a first frequency by a current supplied through the substrate; and It includes a second light-emitting element disposed on the substrate and, by means of a current supplied through the substrate, generating light of a second light-emitting spectrum having a second frequency and at least partially overlapping with the first light-emitting spectrum, and The intensity of the first frequency and the intensity of the second frequency are different from each other. Light-emitting device.

2. In Paragraph 1, The intensity of the first frequency changes according to the current density supplied to the first light-emitting element, and The intensity of the second frequency changes according to the current density supplied to the second light-emitting element. Light-emitting device.

3. In Paragraph 2, When the current density supplied to the first light-emitting element increases, the wavelength of the first frequency decreases and the intensity of the first frequency increases, and when the current density supplied to the first light-emitting element decreases, the wavelength of the first frequency increases and the intensity of the first frequency decreases. When the current density supplied to the second light-emitting element increases, the wavelength of the second frequency decreases and the intensity of the second frequency increases, and when the current density supplied to the second light-emitting element decreases, the wavelength of the second frequency increases and the intensity of the second frequency decreases. Light-emitting device.

4. In Paragraph 1, A controller further comprising a controller for controlling the current density supplied to the first light-emitting element and the current density supplied to the second light-emitting element to control the first frequency and the second frequency, Light-emitting device.

5. In Paragraph 4, The above controller Controlling the current density supplied to the first light-emitting element so that it is smaller than the current density supplied to the second light-emitting element, Light-emitting device.

6. In Paragraph 5, The above controller is configured to further control the current so that current is supplied to the first light-emitting element and the second light-emitting element for a predetermined current supply time, and The first current supply time during which current is supplied to the first light-emitting element is, A second current supply time greater than the second current supply time during which current is supplied to the second light-emitting element, Light-emitting device.

7. In Paragraph 6, The first current supply time during which current is supplied to the first light-emitting element is faster than the second current supply time during which current is supplied to the second light-emitting element. Light-emitting device.

8. In Paragraph 7, The above controller is, A configuration to further control the current such that a section in which current is not supplied to the first light-emitting element and the second light-emitting element is formed between the first current supply time in which current is supplied to the first light-emitting element and the second current supply time in which current is supplied to the second light-emitting element. Light-emitting device.

9. In Paragraph 8, The time of the interval during which the above current is not supplied is shorter than the first current supply time during which current is supplied to the above first light-emitting element. Light-emitting device.

10. In Paragraph 8, The time of the interval during which the above current is not supplied is longer than the first current supply time during which current is supplied to the above first light-emitting element. Light-emitting device.

11. In Paragraph 4, It includes a third light-emitting element disposed on the substrate and, by means of a current supplied through the substrate, generating light of a third light-emitting spectrum having a third frequency and at least partially overlapping with the second light-emitting spectrum, and The above controller is, To control the third frequency, the current density supplied to the third light-emitting element is further controlled, wherein the current density supplied to the third light-emitting element is controlled to be greater than the current density supplied to the second light-emitting element. Light-emitting device.

12. In Paragraph 1, The first light-emitting element and the second light-emitting element generate light such that an overlapping spectrum is formed in which at least a portion of the first light-emitting spectrum and the second light-emitting spectrum overlap each other. Multiple peaks are formed in the above superimposed spectrum, Light-emitting device.

13. In Paragraph 12, The above superimposed spectrum has a color temperature corresponding to white light, Light-emitting device.

14. In Paragraph 1, Each of the first light-emitting element and the second light-emitting element is, First conductivity type semiconductor layer; An active region stacked above the first conductivity type semiconductor layer; and A second conductivity semiconductor layer stacked above the active region, Light-emitting device.

15. In Paragraph 1, Each of the first light-emitting element and the second light-emitting element is, First conductivity type semiconductor layer; A superlattice layer stacked above the first conductivity type semiconductor layer; and A second conductivity type semiconductor layer stacked above the above superlattice layer, The above superlattice layer comprises indium gallium nitride, Light-emitting device.

16. In Paragraph 15, The above superlattice layer is formed in multiple numbers, and The above plurality of superlattice layers, A first superlattice layer stacked above the first conductivity type semiconductor layer; and It includes a second superlattice layer stacked above the first superlattice layer, and The indium content contained in the first superlattice layer and the indium content contained in the second superlattice layer are different. Light-emitting device.

17. Substrate; A first light-emitting element disposed on the substrate and generating light of a first emission spectrum having a first frequency; and It includes a second light-emitting element disposed on the substrate and having a second frequency and generating light of a second light-emitting spectrum that overlaps at least partially with the first light-emitting spectrum, and Each of the first light-emitting element and the second light-emitting element is, First conductivity type semiconductor layer; An active region stacked above the first conductivity type semiconductor layer; A second conductivity type semiconductor layer stacked above the active region; A first electrode electrically connected to the second conductivity type semiconductor layer; and It includes a second electrode electrically connected to the first conductive semiconductor layer, and The second electrode of the first light-emitting element and the second electrode of the second light-emitting element are electrically connected to the second conductive semiconductor layer of the first light-emitting element and the second light-emitting element. Light-emitting device.

18. Substrate; A first active region disposed on the substrate and generating light of a first emission spectrum having a first frequency by a current supplied through the substrate; and It includes a second active region disposed on the substrate and, by a current supplied through the substrate, generating light of a second emission spectrum having a second frequency and at least partially overlapping with the first emission spectrum, and The intensity at the first frequency and the intensity at the second frequency are different, Light-emitting device.

19. In Paragraph 18, The intensity at the first frequency changes according to the current density supplied to the first active region, and The intensity at the second frequency field changes according to the current density supplied to the second active region. Light-emitting device.

20. In Paragraph 18, A controller further comprising a controller configured to control the current density supplied to the first active region and the current density supplied to the second active region so as to control the first frequency and the second frequency. Light-emitting device.

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