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KR-102963823-B1 - LIGHT-EMITTING DEVICE

KR102963823B1KR 102963823 B1KR102963823 B1KR 102963823B1KR-102963823-B1

Abstract

A light-emitting device characterized by comprising at least one of a light-emitting element that emits blue light, a quantum dot that absorbs a portion of the blue light emitted by the light-emitting element and emits green light, a KSF phosphor whose composition is represented by the following chemical formula 1 and which absorbs a portion of the blue light emitted by the light-emitting element and emits red light, and an MGF phosphor whose composition is represented by the following chemical formula 2 and which absorbs a portion of the blue light emitted by the light-emitting element and emits red light. [Chemical Formula 1] [Chemical Formula 2]

Inventors

  • 가와노 겐지
  • 야마모토 아츠시

Assignees

  • 니치아 카가쿠 고교 가부시키가이샤

Dates

Publication Date
20260513
Application Date
20240521
Priority Date
20140924

Claims (10)

  1. As a light-emitting device, Light-emitting element; A light guide plate into which light is incident from the above-mentioned light-emitting element; and A transparent material having a sheet or film shape, comprising: a red phosphor that absorbs a portion of the blue light emitted by the light-emitting element and emits red light; and a green quantum dot that absorbs a portion of the blue light emitted by the light-emitting element and emits green light, wherein the transparent material is spaced apart from a sealing resin covering the light-emitting element. Includes, The light guide plate is disposed between the sealing resin and the light-transmitting material, and A light-emitting device wherein the above red phosphor is at least one of a KSF phosphor represented by the following chemical formula (1) and an MGF phosphor represented by the following chemical formula (2). [Chemical Formula 1] (In Chemical Formula 1, A is at least one selected from the group consisting of K + , Li + , Na + , Rb + , Cs +, and NH4 + , M is at least one element selected from the group consisting of Group 4 elements and Group 14 elements, and a satisfies 0 < a < 0.2.) [Chemical Formula 2] (In Chemical Formula 2, x, y, z, a, b, and c satisfy 2.0≤x≤4.0, 0＜y＜1.5, 0＜z＜0.05, 0≤a＜0.5, 0＜b＜0.5, 0≤c＜1.5, and y+c＜1.5, and Mt is at least one selected from Al, Ga, and In.)
  2. A light-emitting device according to claim 1, wherein the light-transmitting material is an organic polymer.
  3. A light-emitting device according to claim 1, wherein the light-transmitting material is polymethyl methacrylate resin.
  4. A light-emitting device according to claim 1, wherein the full width at half maximum of the emission peak of the red phosphor is 35 nm or less.
  5. A light-emitting device according to claim 1, wherein the peak of the emission wavelength of the green quantum dot is 510 to 560 nm.
  6. A light-emitting device according to claim 1, wherein the full width at half maximum of the emission peak of the green quantum dot is 40 nm or less.
  7. A light-emitting device according to claim 1, wherein the particle size of the green quantum dot is 1 to 20 nm.
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Description

Light-Emitting Device The present disclosure relates to a light-emitting device, in particular, comprising a light-emitting element that emits blue light and a quantum dot that absorbs a portion of the blue light emitted by the light-emitting element and emits green light. A light-emitting device that emits white light is conventionally known to include a light-emitting element that emits blue light, a green phosphor (or a yellow-green phosphor that emits yellow-green light) that absorbs a portion of the blue light emitted by the light-emitting element and emits green light, and a red phosphor that absorbs a portion of the blue light emitted by the light-emitting element and emits red light. Such a light-emitting device that emits white light is used for various applications, including backlights and lighting devices for various displays such as liquid crystal displays. Recently, light-emitting devices have been developed in which all or part of a phosphor is replaced with quantum dots (QDs). Quantum dots are semiconductor particles with a diameter of several nanometers to tens of nanometers, and, like phosphors, they absorb light such as blue light emitted by a light-emitting device and emit light different from the absorbed light. A light-emitting device is known that does not include a green phosphor and a red phosphor, but includes a green quantum dot that emits green light by absorbing blue light emitted by a light-emitting element, and a red quantum dot that emits red light by absorbing blue light emitted by a light-emitting element. Additionally, Patent Document 1 discloses a light-emitting device that includes a yellow-green phosphor and a red quantum dot. Quantum dots are characterized by a sharp emission peak, meaning the full width at half maximum of the emission peak is small (narrow). Consequently, light-emitting devices using quantum dots offer the advantage of a wider color reproduction range when combined with color filters, such as those in liquid crystal displays. Furthermore, by aligning the peak wavelength of the color filter (the wavelength at which transmittance peaks) with the emission peak of the quantum dot, more light can pass through the color filter. This results in less light attenuation when using the color filter, thereby improving light extraction efficiency. In particular, since conventional green phosphors and yellow-green phosphors had broad emission peaks, these effects can be obtained more significantly by using green quantum dots. FIG. 1 is a schematic cross-sectional view of a light-emitting device (100) according to embodiment 1. FIG. 2 is a diagram showing a preferred chromaticity range of light emitted from a light-emitting element package (10) on a chromaticity coordinate system. Figure 3a is an SEM image showing a portion of the cross-section of the fabricated light-emitting device package (10). Figure 3b is an enlarged SEM image of part A of Figure 3a. Figure 3c is an enlarged SEM image of part B of Figure 3a. Figure 3d is an enlarged SEM image of part C of Figure 3a. Figure 3e is an enlarged SEM image of part D of Figure 3b. Figure 4 is the emission spectrum of the obtained light-emitting device package (10). FIG. 5 is a schematic cross-sectional view of a light-emitting device (100A) according to embodiment 2. FIG. 6a is a schematic cross-sectional view illustrating the advantages of a light-emitting device (100) and shows an embodiment in which a red phosphor (14) is placed inside a sealing resin (12). FIG. 6b is a schematic cross-sectional view illustrating the advantages of a light-emitting device (100) and shows an embodiment in which a red phosphor (14) is placed inside a transparent material (22). FIG. 7 is a schematic cross-sectional view illustrating a liquid crystal display (200) using a light-emitting device (100B) according to embodiment 3. Embodiments of the present invention will be described below with reference to the drawings. However, please note that the embodiments described below are intended to embody the technical concept of the present invention and are not intended to limit the technical scope of the present invention. The configurations described in one embodiment may be applied to other embodiments unless otherwise noted. In the following description, terms indicating specific directions or positions (e.g., "up," "down," "right," "left," and separate terms including these) are used as needed; the use of such terms is intended to facilitate understanding of the invention with reference to the drawings, and the technical scope of the present invention is not limited by the meaning of such terms. Please note that the sizes and positional relationships of the components shown in each drawing may be exaggerated for the sake of clarity. Additionally, parts with the same reference numeral appearing in multiple drawings represent the same part or component. Furthermore, unless otherwise specified, components indicated by a symbol consisting of