White light emitting device and display equipment

Abstract

A white light emitting device and a display apparatus are provided. The white light emitting device includes: a package substrate; a body having an opening exposing a portion of an upper surface of the package substrate; a first blue light emitting diode (LED) chip disposed on the portion of the upper surface of the package substrate and emitting a first blue light having a first peak wavelength; a second blue light LED chip disposed on the portion of the upper surface of the package substrate and emitting a second blue light having a second peak wavelength different from the first peak wavelength; and a wavelength conversion portion disposed in the opening and covering the first blue light LED chip and the second blue light LED chip, and generating white light from the first blue light and the second blue light.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2024-0025759 filed on February 22, 2024, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present inventive concept relates to a white light emitting device and a display apparatus. Background Art

[0004] Typically, white light emitting devices can be manufactured by combining blue light emitting diode (LED) chips with various wavelength conversion materials. White light emitting devices have been used as the light source for the backlight of display devices. These LED display devices have been widely used in various fields, such as learning monitors, tablet PCs, gaming monitors, and vehicle displays. Summary of the Invention

[0005] An aspect of the present inventive concept is to provide a white light emitting device having an excellent (or wide) color gamut while enhancing conditions for human-oriented lighting.

[0006] Another aspect of the present inventive concept is to provide a display device having an excellent color gamut while enhancing conditions of lighting facing people.

[0007] According to one aspect of the present disclosure, a white light emitting device includes: a first light emitting diode (LED) chip that emits light having a peak wavelength within a range of 425 nm to 455 nm; a second LED chip that emits light having a peak wavelength within a range of 460 nm to 470 nm; a first wavelength conversion material disposed in a path of light emitted from the first and second LED chips and converting a portion of the emitted light into first light; and a second wavelength conversion material disposed in a path of light emitted from the first and second LED chips and converting a portion of the emitted light into second light. The first light, the second light, and the light emitted from each of the first and second LED chips form white light as output of the white light emitting device. The first light has a peak wavelength within a range of 520 nm to 550 nm, and the second light has a peak wavelength within a range of 610 nm to 650 nm and a full width at half maximum (FWHM) of 50 nm or less. White light of the white light emitting device has a melanopic ratio (M / P ratio) of 1.3 or more and has a color gamut having a coverage of 90% or more with respect to the DCI-P3 color gamut standard.

[0008] According to one aspect of the present disclosure, a white light emitting device includes: a first light emitting diode (LED) chip that emits light having a peak wavelength in the range of 425nm to 455nm; a second LED chip that emits light having a peak wavelength in the range of 460nm to 470nm; a first wavelength conversion material that is disposed at a travel path of light emitted from the first LED chip and the second LED chip and converts a portion of the emitted light into a first light having a peak wavelength in the range of 520nm to 550nm; and a second wavelength conversion material that is disposed at a travel path of light emitted from the first LED chip and the second LED chip and converts a portion of the emitted light into a second light having a peak wavelength in the range of 610nm to 650nm. The first light, the second light, and the light emitted from each of the first LED chip and the second LED chip form white light as the output of the white light emitting device. The second wavelength conversion material includes a fluoride phosphor having a composition formula of A x MF y :Mn 4+ , wherein A is at least one selected from Li, Na, K, Rb, and Cs, M is at least one selected from Si, Ti, Zr, Hf, Ge, and Sn, and the composition formula satisfies 2≤x≤3 and 4≤y≤7. The blue light hazard (BLH) value of the white light of the white light emitting device is 0.0018W / m 2 The white light has a color gamut with 90% or greater coverage with respect to the DCI-P3 color gamut standard.

[0009] According to one aspect of the present disclosure, a display device includes: an image display panel having a color filter layer including a red filter, a green filter, and a blue filter; and a backlight unit disposed on a lower surface of the image display panel and having a plurality of light sources. Each of the plurality of light sources includes a white light emitting device, the white light emitting device including: a first light emitting diode (LED) chip emitting light having a peak wavelength in a range of 425nm to 455nm; a second LED chip emitting light having a peak wavelength in a range of 460nm to 470nm; a first wavelength conversion material disposed at a path of light emitted from the first and second LED chips and converting a portion of the emitted light into the first light; and a second wavelength conversion material disposed at a path of light emitted from the first and second LED chips and converting a portion of the emitted light into the second light. The first light has a peak wavelength in a range of 520nm to 550nm, and the second light has a peak wavelength in a range of 610nm to 650nm and a full width at half maximum (FWHM) of 50nm or less. The first light, the second light, and the light emitted from each of the first and second LED chips form white light as an output of the white light emitting device. The white light from each of the plurality of light sources has a melanopic ratio of 1.3 or greater. The color gamut of the light emitted from the image display panel has a coverage of 90% or greater with respect to the DCI-P3 color gamut standard.

[0010] According to one aspect of the present disclosure, a white light emitting device includes: a packaging substrate; a main body having an opening exposing a portion of an upper surface of the packaging substrate; a first blue light emitting diode (LED) chip, which is arranged on the portion of the upper surface of the packaging substrate and emits a first blue light having a first peak wavelength; a second blue light LED chip, which is arranged on the portion of the upper surface of the packaging substrate and emits a second blue light having a second peak wavelength different from the first peak wavelength; and a wavelength conversion portion, which is arranged in the opening and covers the first blue light LED chip and the second blue light LED chip, and generates white light from the first blue light and the second blue light. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The above and other aspects, features and advantages of the present inventive concept will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0012] Figure 1 is a schematic cross-sectional view illustrating a white light emitting device according to an example embodiment of the inventive concept;

[0013] Figure 2 is an emission spectrum of light emitted from a white light emitting device according to an example embodiment of the inventive concept;

[0014] Figure 3 is an emission spectrum of light emitted from a white light emitting device according to a specific example embodiment (Example 1) and a comparative example (Comparative Example 1) of the present inventive concepts;

[0015] Figure 4 are emission spectra of light emitted from white light emitting devices according to a specific example embodiment (Example 2) and comparative examples (Comparative Example 2A and Comparative Example 2B) of the present inventive concepts;

[0016] Figure 5A and Figure 5B is a cross-sectional view of an LED chip suitable for a white light emitting device according to an exemplary embodiment of the inventive concept;

[0017] Figure 6A and Figure 6B are a schematic cross-sectional view and a schematic perspective view respectively illustrating a white light emitting device according to an example embodiment of the inventive concept;

[0018] Figure 7 is a schematic cross-sectional view illustrating a white light emitting device according to an example embodiment of the inventive concept;

[0019] Figure 8 is an emission spectrum of light emitted from a white light emitting device according to an example embodiment of the inventive concept;

[0020] Figure 9 is a block diagram of a display device according to an example embodiment of the inventive concept;

[0021] Figure 10 is a schematic cross-sectional view of a display device according to an example embodiment of the inventive concept; and

[0022] Figure 11 is a schematic exploded perspective view of a display device according to an example embodiment of the inventive concept. DETAILED DESCRIPTION

[0023] Hereinafter, example embodiments of the inventive concept are described with reference to the accompanying drawings.

[0024] Figure 1 is a schematic cross-sectional view illustrating a white light emitting device according to an example embodiment of the inventive concept.

[0025] Reference Figure 1The white light emitting device 100 according to the present exemplary embodiment may include a package substrate 10, a first blue light emitting diode (LED) chip 30A and a second blue light emitting diode (LED) chip 30B disposed on the package substrate 10, and a wavelength conversion portion 50. The white light emitting device 100 may further include a pair of lead frames 11 and 12 electrically connected to the first blue LED chip 30A and the second blue LED chip 30B, a side wall reflector 20 having a recess C, and wires CW connecting the first blue LED chip 30A and the second blue LED chip 30B to the lead frames 11 and 12.

[0026] For example, the package substrate 10 may be molded from an opaque resin or a resin having high reflectivity, which may facilitate the injection process, and may include a polymer resin containing highly reflective powder. Alternatively, the package substrate 10 may be formed from ceramic, in which case heat dissipation may be facilitated. In some example embodiments, the package substrate 10 may be a printed circuit board on which an interconnection pattern is formed in place of the lead frames 11 and 12.

[0027] The side wall reflector 20 may be provided on the package substrate 10, and the first blue LED chip 30A and the second blue LED chip 30B may be arranged on the package substrate 10 within the recess C and electrically connected to the lead frames 11 and 12. The side wall reflector 20 may have a cup shape to improve light reflection efficiency, but is not limited thereto. In some example embodiments, the side wall reflector 20 may be provided as a body integrated with the package substrate 10 as part of the body. For example, the side wall reflector 20 and the package substrate 10 may be formed of the same material (e.g., a resin including highly reflective white powder) by the same process (e.g., injection molding).

[0028] The first blue LED chip 30A and the second blue LED chip 30B used in this example embodiment can each be configured to emit blue light having different wavelengths. By combining the first and second blue lights having two different wavelengths, the amount of light in the wavelength band between the two can be reduced. In some example embodiments, the first blue LED chip 30A can be configured to emit first blue light having a peak wavelength in the range of 425nm to 455nm, and the second blue LED chip 30B can be configured to emit second blue light having a peak wavelength in the range of 460nm to 470nm.

[0029] Figure 2 φ is an emission spectrum of light emitted from a white light emitting device according to an example embodiment of the inventive concept.

[0030] like Figure 2As shown, in the emission spectrum of the final light, the blue band (i.e., the melanopsin sensitive band (MS)) where the blue light hazard (BLH) is concentrated is adjusted to reduce the harmfulness of the white light emitting device 100 due to the BLH. In addition, it can help improve attention by inhibiting the secretion of melatonin, which affects enzymes related to biological rhythms and attention. Figure 2 In the emission spectrum A1 shown, the blue light wavelengths of the first and second blue LED chips can be designed as described above to reduce the wavelength band specifically including 430 nm to 450 nm (which is the peak wavelength band of BLH in the melanopsin sensitive band (MS)).

[0031] Thus, the white light emitting device 100 according to this exemplary embodiment minimizes BLH by introducing the first blue LED chip 30A and the second blue LED chip 30B, each emitting blue light having a different wavelength, while suppressing the secretion of melatonin, thereby helping to improve attention. For example, the final light of the white light emitting device 100 may have a power of 0.0018 W / m 2 or less BLH value. At the same time, the melanopic ratio (M / P) of the final light can be 1.3 or greater (see Tables 1 and 2 below). Therefore, the white light emitting device 100 according to this exemplary embodiment can be advantageously used as a display light source facing people.

[0032] The wavelength conversion portion 50 may be disposed on an optical path of the first blue LED chip 30A and the second blue LED chip 30B and may include a plurality of wavelength conversion materials 55. In this exemplary embodiment, the plurality of wavelength conversion materials 55 may include a first wavelength conversion material 55G that converts a portion of the first blue light and a portion of the second blue light into first light having a peak wavelength in the range of 520 nm to 550 nm, and a second wavelength conversion material 55R that converts a portion of the first blue light and a portion of the second blue light into second light having a peak wavelength in the range of 610 nm to 650 nm.

[0033] For example, the first wavelength conversion material 55G may include at least one of (Ba, Sr) 2 SiO 4 : Eu and β-SiAlON: Eu. The second wavelength conversion material 55R employed in this exemplary embodiment may be configured so that the converted second light has a full width at half maximum (FWHM) of 50 nm or less. In this way, by introducing a second wavelength conversion material having a smaller FWHM than other general phosphors, an excellent color gamut may be ensured while maintaining a high luminous flux. For example, the second wavelength conversion material 55R may include a composition of formula A x MF y :Mn 4+Here, A is at least one selected from Li, Na, K, Rb, and Cs, M is at least one selected from Si, Ti, Zr, Hf, Ge, and Sn, and the composition formula satisfies 2≤x≤3 and 4≤y≤7. In some example embodiments, the second wavelength conversion material 55R may be K2SiF6:Mn 4+ Phosphor.

[0034] Therefore, the white light emitting device 100 according to the present exemplary embodiment can be used as an excellent display light source. Specifically, the final light of the white light emitting device 100 can have a wide color gamut with a coverage of 90% or more with respect to the Digital Cinema Initiative-Protocol 3 (DCI-P3) color gamut standard. In addition, the luminous efficacy (LER) of the final light can be 220 W / m 2 or greater (see Tables 1 and 2 below).

[0035] The white light emitting device 100 according to the present example embodiment may be constructed such that the first light and the second light having different wavelengths excited by the first blue light and the second blue light generated by the first blue LED chip 30A and the second blue LED chip 30B to be converted are combined with the unconverted portion of the first blue light and the unconverted portion of the second blue light to ultimately emit white light.

[0036] These first wavelength conversion material 55G and second wavelength conversion material 55R can be mixed in appropriate amounts so that the final light from the white light emitting device 100 has a desired white light according to the conversion wavelength and conversion efficiency. The CIE 1931 color coordinates of the final light according to this example embodiment may be (0.270 < X ​​< 0.280, 0.235 < Y < 0.245). In some example embodiments, the color temperature of the final light may be 19000K or higher (see Tables 1 and 2 below).

[0037] In some example embodiments, in addition to a fluoride phosphor having a small FWHM, the second wavelength conversion material 55R may further include (Sr,Ca)AlSiN3:Eu and CaAlSiN3:Eu. In this example embodiment, the plurality of wavelength conversion materials 55G and 55R may be dispersed in the transparent resin 51 of the wavelength conversion portion 50. For example, the transparent resin 51 may be formed from epoxy resin, silicone, modified silicone, polyurethane resin, oxetane resin, acrylic fiber, polycarbonate, polyimide, or a combination thereof. In some example embodiments, the first wavelength conversion material 55G and the second wavelength conversion material 55R may not be dispersed in the transparent resin 51. Instead, the first wavelength conversion material 55G and the second wavelength conversion material 55R may be directly applied to the surfaces of the first blue LED chip 30A and the second blue LED chip 30B, or may be provided as a film including the wavelength conversion material on the transparent resin 51.

[0038] Hereinafter, in order to confirm the desired requirements of the white light emitting device according to the present example embodiment, white light emitting devices were prepared according to the conditions in Table 1 below, and white light characteristics of each white light emitting device were measured (see Table 2 below).

[0039] The white light emitting devices according to the following comparative examples and examples are generally manufactured to have the same Figure 1 The white light emitting device shown has a similar structure, β-SiAlON:Eu with a peak wavelength of 540nm to 545nm is used as the first wavelength conversion material, and other conditions (for example, the mixing ratio of the first wavelength conversion material and the second wavelength conversion material, etc.) are appropriately designed to emit almost the same white light. Each white light is designed to meet the CIE 1931 color coordinates (0.270<X<0.280, 0.235<Y<0.245). As shown in Table 1 below, the Committee International Standard (CIE) 1931 color coordinates of the example are (0.274, 0.240), and the comparative example may have similar color coordinates, although there are some differences. In each example embodiment, the color temperature of the final light can be 19000K or higher.

[0040] In each of Comparative Example 1, Comparative Example 2A and Comparative Example 2B, and Examples 1A to 1G and Examples 2A to 2G, the two blue LED chips have different peak wavelength conditions. Specifically, in each example embodiment, the emission wavelength of the first blue LED chip varies within the range of 420nm to 455nm (varies in units of 5nm), and the emission wavelength of the second blue LED chip is set to 460nm and 465nm. In Comparative Example 2A and Comparative Example 2B, the emission wavelength of the first blue LED chip is set to 425nm, and the emission wavelength of the second blue LED chip is set to 460nm and 465nm. However, in Comparative Example 1, the emission wavelengths of the two blue LED chips are set to the same peak wavelength (450nm).

[0041] Meanwhile, in the example, K2SiF6:Mn 4+ is used as the second wavelength conversion material. In Comparative Example 1, the same K2SiF6:Mn 4+ , but in Comparative Examples 2A and 2B, CaAlSiN3:Eu was used.

[0042] Table 1

[0043]

[0044] Thus, Comparative Example 1 differs from each example in that the first blue LED chip and the second blue LED chip have the same emission wavelength, and Comparative Examples 2A and 2B differ from each example in that K2SiF6:Mn 4+ Other red phosphors.

[0045] Figure 3 is an emission spectrum of light emitted from a white light emitting device according to an example (Example 2C: A1) and a comparative example (Comparative Example 1: B1) of the present inventive concept, Figure 4 are emission spectra of light emitted from the white light emitting devices according to the example (Example 1D: A2) and the comparative examples (Comparative Examples 2A and 2B: C1 and C2, respectively).

[0046] The M / P ratio and BLH characteristics of the final white light of the white light emitting device according to Table 1 above and the improvement rate (reference: Comparative Example 2A), the luminous efficacy (LER) and improvement rate as an indicator of light output, and the DCI coverage are measured and shown in Table 2 below.

[0047] Table 2

[0048]

[0049] As for the M / P ratio and BLH characteristics, it can be seen that Examples 1F and 1G, as well as Examples 2A to 2G, have improved by 1% to 13%, and Examples 1A to 1E have also shown significant improvement compared to Comparative Example 1. Specifically, the M / P ratio of the white light according to the Examples is 1.35 or greater, and the BLH value is 0.0018 W / m 2 or smaller.

[0050] At the same time, in terms of luminous flux and color reproduction range, it can be seen that not only the DCI coverage according to the example is as high as 90% or higher (95% in some examples), but also the luminous flux (LER) is improved by 10% or higher compared with Comparative Example 2A. Specifically, the LER of the white light according to the example can be 220 W / m 2 Specifically, in terms of DCI coverage, it can be seen that when K2SiF6:Mn 4+ When used as the second wavelength conversion material (Comparative Example 2A versus Example 2A, Comparative Example 2B versus Example 1A), each increased by approximately 3%.

[0051] As such, the white light emitting device according to the present exemplary embodiment has a high luminous flux while maintaining a high color reproduction range, and thus can be effectively used as an excellent display light source.

[0052] Figure 5A and Figure 5B is a cross-sectional view of an LED chip suitable for a white light emitting device according to an example embodiment of the inventive concept. Figure 5A and Figure 5B At least one of the LED chips 30 and 30 ′ shown in FIG. 5 may be used as the first blue LED chip 30A and the second blue LED chip 30B of the white light emitting device 100 described above.

[0053] Reference Figure 5A , the LED chip 30 employed in this exemplary embodiment includes a substrate 31 and a semiconductor stack S disposed on the substrate 31. The semiconductor stack S may include a first conductive type semiconductor layer 34, an active layer 35, and a second conductive type semiconductor layer 36 sequentially disposed on the substrate 31. A buffer layer 32 may be additionally disposed between the substrate 31 and the first conductive type semiconductor layer 34.

[0054] The substrate 31 may be an insulating substrate such as sapphire. However, the present invention is not limited thereto, and the substrate 31 may be a conductive substrate or a semiconductor substrate. For example, the substrate 31 may be SiC, Si, MgAl2O4, MgO, LiAlO2, LiGaO2, or GaN. Irregularities P may be formed on the upper surface of the substrate 31. The irregularities P may improve the quality of the grown single crystal while increasing light extraction efficiency.

[0055] The buffer layer 32 may include undoped In x Al y Ga 1-x-y N (0≤x≤1, 0≤y≤1). For example, the buffer layer 32 may be GaN, AlN, AlGaN, or InGaN. If necessary, multiple layers may be combined, or the composition may be gradually changed for use.

[0056] The first conductive type semiconductor layer 34 may be an N-type In x Al y Ga 1-x-y The first conductive type semiconductor layer 34 may include an N-type GaN. The second conductive type semiconductor layer 36 may include a P-type Indium nitride semiconductor. x Al y Ga 1-x-y The second conductive type semiconductor layer 36 may be a nitride semiconductor layer of N (0≤x<1, 0≤y<1, 0≤x+y<1), and the P-type impurity may be Mg. For example, the second conductive type semiconductor layer 36 may be implemented as a single-layer structure, but as in this example, the second conductive type semiconductor layer 36 may have a multi-layer structure having different compositions.

[0057] The active layer 35 may have a multi-quantum well (MQW) structure in which quantum well layers and quantum barrier layers are alternately stacked. For example, the quantum well layers and quantum barrier layers may be In layers having different compositions. x Al y Ga 1-x-y N(0≤x≤1, 0≤y≤1, 0≤x+y≤1). In a specific example, the quantum well layer can be In x Ga 1-x N(0<x≤1), and the quantum barrier layer can be GaN or AlGaN. The thickness of the quantum well layer and the quantum barrier layer can each be in the range of 1nm to 50nm. The active layer 35 is not limited to a multi-quantum well structure and can be a single quantum well structure.

[0058] The first electrode 39a and the second electrode 39b may be respectively disposed on the mesa-etched region of the first conductive type semiconductor layer 34 and the second conductive type semiconductor layer 36 so as to be located on the same surface (first surface). The first electrode 39a may include, but is not limited to, materials such as Ag, Ni, Al, Cr, Rh, Pd, Ir, Ru, Mg, Zn, Pt, and Au, and may have a single-layer or two-layer structure. In some example embodiments, the second electrode 39b may be a transparent electrode such as a transparent conductive oxide or a transparent nitride, or may include graphene. The second electrode 39b may include at least one of Al, Au, Cr, Ni, Ti, and Sn.

[0059] Reference Figure 5B The LED chip 30' according to this exemplary embodiment can be understood as including, in addition to the electrode structure and its related structures, Figure 5A Unless otherwise specified, the description of the components of this example embodiment may refer to the description of the components of the LED chip 30 shown in FIG. Figure 5A The LED chip 30 shown in FIG. 3 is the same as or similar to the components described above.

[0060] The LED chip 30' includes a first electrode 42 and a second electrode 44 connected to the first and second conductive type semiconductor layers 34, 36, respectively. The first electrode 42 may include a connecting electrode portion 42a that passes through the second conductive type semiconductor layer 36 and the active layer 35 and connects to the first conductive type semiconductor layer 34, and a first electrode pad 42b connected to the connecting electrode portion 42a. The connecting electrode portion 42a may have a structure such as a conductive via. The connecting electrode portion 42a may be surrounded by an insulating portion 41 and electrically isolated from the active layer 35 and the second conductive type semiconductor layer 36. The connecting electrode portions 42a may be disposed in the etched region of the semiconductor stack S. The number, shape, and spacing of the connecting electrode portions 42a, as well as the contact area between the connecting electrode portions 42a and the first conductive type semiconductor layer 34, may be appropriately designed to reduce contact resistance. Furthermore, the connecting electrode portions 42a may be arranged in rows and columns on the semiconductor stack S to improve current flow. The second electrode 44 may include an ohmic contact layer 44a and a second electrode pad 44b on the second conductive type semiconductor layer 36.

[0061] The connection electrode portion 42a and the ohmic contact layer 44a may include a single layer or a multilayer structure formed of a conductive material having ohmic characteristics with the first conductive type semiconductor layer 34 and the second conductive type semiconductor layer 36, respectively. For example, the connection electrode portion 42a and the ohmic contact layer 44a may be formed by a process such as depositing or sputtering one or more of a metal (such as Ag, Al, Ni, Cr) and a transparent conductive oxide (TCO) (such as ITO).

[0062] The first electrode pad 42b and the second electrode pad 44b may be connected to the connection electrode portion 42a and the ohmic contact layer 44a, respectively, and may serve as external terminals of the LED chip 30'. For example, the first electrode pad 42b and the second electrode pad 44b may be Au, Ag, Al, Ti, W, Cu, Sn, Ni, Pt, Cr, NiSn, TiW, AuSn, or eutectic metals thereof.

[0063] The first electrode 42 and the second electrode 44 can be arranged in the same direction and can be mounted on a lead frame or the like in a so-called flip-chip form. At the same time, the two electrodes 42 and 44 can be electrically isolated from each other by the insulating portion 41. The insulating portion 41 can be formed of any material having electrically insulating properties. Although any material having electrically insulating properties can be used as the insulating portion 41, a material with low light absorptivity can be used. For example, silicon oxide or silicon nitride can be used. If necessary, a light reflective structure can be formed by dispersing light reflective powder particles in a light-transmitting material. In an embodiment, the insulating portion 41 can be a multilayer reflective structure in which a plurality of insulating films having different refractive indices are alternately stacked. For example, the multilayer reflective structure can be a distributed Bragg reflector (DBR), in which a first insulating film having a first refractive index and a second insulating film having a second refractive index are alternately stacked.

[0064] In the multilayer reflective structure, a plurality of insulating films having different refractive indices may be repeatedly stacked 2 to 100 times. For example, the plurality of insulating films may be repeatedly stacked 3 to 70 times, and further, may be repeatedly stacked 4 to 50 times. Each of the plurality of insulating films of the multilayer reflective structure may be an oxide or a nitride, such as SiO2, SiN, SiO x N y , TiO2, Si3N4, Al2O3, TiN and AlN, and combinations thereof. The refractive index of the first insulating film and the second insulating film may be determined in the range of about 1.4 to about 2.5, and may be a value smaller than the refractive index of the first conductive type semiconductor layer 34 and the refractive index of the substrate 31, or may be a value smaller than the refractive index of the first conductive type semiconductor layer 34 but greater than the refractive index of the substrate 31.

[0065] Figure 6A and Figure 6B 1 and 2 are respectively a schematic cross-sectional view and a schematic perspective view illustrating a white light emitting device according to an example embodiment of the inventive concept. Figure 6A yes Figure 6B : is a cross-sectional view of the white light emitting device shown in FIG. 1 taken along line II′.

[0066] Reference Figure 6A and Figure 6B The white light emitting device 100A according to the present exemplary embodiment can be understood as follows, except that the package substrate 10' and the body of the side wall reflector 20' respectively have a first concave portion C1 and a second concave portion C2 extending in one direction, a plurality of first blue LED chips 30A and a second blue LED chip 30B are flip-chip-bonded side by side in the first concave portion C1 and the second concave portion C2, and the first wavelength conversion portion 50A and the second wavelength conversion portion 50B are respectively disposed in the first concave portion C1 and the second concave portion C2. Figure 1 The white light emitting device 100 shown in FIG.

[0067] In this exemplary embodiment, the body of the white light emitting device 100A includes a strip-shaped package substrate 10' and a sidewall reflector 20' disposed on the package substrate 10' and having a first concave portion C1 and a second concave portion C2 extending in one direction. In some exemplary embodiments, the sidewall reflector 20' may be provided as a body integrated with the package substrate 10'. For example, the sidewall reflector 20' and the package substrate 10' may be formed of the same reflective material through the same process (e.g., injection molding).

[0068] The package substrate 10' includes a pair of first electrode structures 11a and 12a disposed in a region corresponding to the first concave portion C1, and a pair of second electrode structures 11b and 12b disposed in a region corresponding to the second concave portion C2. Each of the first electrode structures 11a and 12a and the second electrode structures 11b and 12b employed in this exemplary embodiment may include an upper pad, a lower pad, and an interconnection portion connecting the upper pad and the lower pad to each other.

[0069] In this exemplary embodiment, the first blue LED chip 30A and the second blue LED chip 30B can be arranged side by side in the first recess and the second recess, and can be flip-chips bonded to the first electrode structures 11a and 12a and the second electrode structures 11b and 12b, respectively. Specifically, the first blue LED chip 30A can be electrically connected to the first electrode structures 11a and 12a (specifically, the upper pads) via connecting conductors S1a and S1b, and the second blue LED chip 30B can be electrically connected to the second electrode structures 11b and 12b (specifically, the upper pads) via connecting conductors S2a and S2b. In this embodiment, the first recess and the second recess are separated by a partition wall PW.

[0070] As described in the previous example embodiments, the first blue LED chip 30A and the second blue LED chip 30B can be configured to emit blue light having different wavelengths. In some example embodiments, the first blue LED chip 30A can be configured to emit a first blue light having a peak wavelength in the range of 425nm to 455nm, and the second blue LED chip 30B can be configured to emit a second blue light having a peak wavelength in the range of 460nm to 470nm. In this way, the white light emitting device 100A can reduce the harmfulness caused by BLH by introducing first and second blue lights having different wavelengths. In addition, it can help improve attention by suppressing the secretion of melatonin, which affects enzymes related to biological rhythms and attention.

[0071] In some example embodiments, the intensity ratio of the first blue light and the second blue light having different wavelengths can be adjusted by controlling the voltage applied to the first blue LED chip 30A and the second blue LED chip 30B through the first electrode structures 11a and 12a and the second electrode structures 11b and 12b, and the first blue LED chip 30A and the second blue LED chip 30B are independently supplied with voltages. The voltage supplied to the first blue LED chip 30A via the first electrode structures 11a and 12a can be independently controlled relative to the voltage supplied to the second blue LED chip 30B via the second electrode structures 11b and 12b.

[0072] The first and second wavelength conversion sections 50A and 50B are disposed in separate first and second recesses C1 and C2, respectively, along the optical paths of the first and second blue LED chips 30A and 30B. In this exemplary embodiment, each of the first and second wavelength conversion sections 50A and 50B may include a transparent resin 51 and a plurality of wavelength conversion materials 55 mixed within the transparent resin 51. The first and second wavelength conversion sections 50A and 50B may include the same type of wavelength conversion material. For example, the wavelength conversion materials 55 may include a first wavelength conversion material 55G and a second wavelength conversion material 55R. The first wavelength conversion material 55G converts a portion of the emitted first and second blue lights into first light having a peak wavelength in the range of 520 nm to 550 nm, and the second wavelength conversion material 55R converts a portion of the first and second blue lights into second light having a peak wavelength in the range of 610 nm to 650 nm.

[0073] For example, the first wavelength conversion material 55G may include at least one of (Ba, Sr) 2 SiO 4 :Eu and β-SiAlON:Eu. The second wavelength conversion material 55R employed in this exemplary embodiment may be configured so that the converted second light has a FWHM of 50 nm or less. For example, the second wavelength conversion material 55R may include a material having a composition formula Ax MF y :Mn 4+ Here, A is at least one selected from Li, Na, K, Rb, and Cs, M is at least one selected from Si, Ti, Zr, Hf, Ge, and Sn, and the composition formula satisfies 2≤x≤3 and 4≤y≤7. In some example embodiments, the second wavelength conversion material 55R may be K2SiF6:Mn 4+ Phosphor.

[0074] The first wavelength conversion material 55G and the second wavelength conversion material 55R can be mixed in appropriate amounts so that the final light from the white light emitting device 100A has the desired white light according to the conversion wavelength and conversion efficiency. In an embodiment, the first wavelength conversion material and the second wavelength conversion material can be provided in particles. The CIE1931 color coordinates of the final light according to this example embodiment can be (0.270 <X <0.280, 0.235 <Y <0.245). In some example embodiments, the color temperature of the final light can be 19000K or higher.

[0075] In addition, the final light of the white light emitting device 100A may have a wide color gamut having a coverage of 90% or more with respect to the DCI-P3 color gamut standard. In addition, the luminous efficacy (LER) of the final light may be 220 W / m 2 or larger.

[0076] Therefore, the white light emitting device 100A according to the present exemplary embodiment may be advantageously used as a display light source facing people.

[0077] Figure 7 is a schematic cross-sectional view illustrating a white light emitting device according to an example embodiment of the inventive concept.

[0078] Reference Figure 7 The white light emitting device 100B according to this exemplary embodiment may be understood as including a near-infrared phosphor as a wavelength conversion material in addition to the white light emitting device 100B. Figure 1 In addition, unless otherwise specified, reference can be made to Figure 1 The components of this example embodiment may be understood by referring to the description of the same or similar components of the white light emitting device 100 shown in FIG.

[0079] The wavelength conversion portion 50C employed in this exemplary embodiment may include a near-infrared phosphor 55N and the first wavelength conversion material 55G and the second wavelength conversion material 55R described in the previous exemplary embodiment. The near-infrared phosphor 55N employed in this exemplary embodiment may be configured to convert a portion of the light emitted from the first blue LED chip 30A and the second blue LED chip 30B into light having a peak wavelength of 740 nm to 900 nm. In addition, the FWHM of the emission spectrum may be within a range of 90 nm to 110 nm. For example, the near-infrared phosphor 55N includes a material having a composition formula of Ca(Al 12-x-y ,Ga y )O 19 :xCr 3+ A phosphor represented by , wherein x satisfies 0.1≤x≤0.3 and y satisfies 3 or greater.

[0080] Figure 8 1 shows an example of an emission spectrum of light emitted from a white light emitting device 100B according to an exemplary embodiment of the present inventive concept. The white light emitting device 100B according to this exemplary embodiment can be understood as a device in which a near-infrared phosphor 55N is added to the white light emitting device 100B. Figure 1 The white light emitting device 100 is in the form of, and Figure 8 The emission spectrum includes the emission spectrum of the near-infrared phosphor 55N in Figure 2 Additional converted light in the emission spectrum (NIR).

[0081] Reference Figure 8 The light converted by the near-infrared phosphor 55N can be combined with the second light (e.g., red light) converted by the second wavelength conversion material 55R to cover a significant portion of the adenosine triphosphate (ATP) action spectrum. Therefore, the white light emitting device 100B according to this exemplary embodiment can be provided as a human-oriented display light source module having enhanced bioenergetic functionality in terms of the ATP action spectrum due to the addition of the near-infrared phosphor 55N.

[0082] Figure 9 is a block diagram of a display device according to an example embodiment of the inventive concept.

[0083] Reference Figure 9 The display device 500 according to this exemplary embodiment may include a display panel 150 and a processor 110. The display panel 150 may include an LCD panel 152 and a backlight panel 154, and the backlight panel 154 may employ the white light emitting devices 100, 100A, and 100B according to the above exemplary embodiments as a light source module.

[0084] The display device 500 may adjust the transmittance of light reaching the liquid crystals of the LCD panel 152 from the backlight panel 154 by controlling voltage and / or current.

[0085] The display device 500 can reproduce a desired image by adjusting the transmittance of the liquid crystal. The display device 500 can change the intensity of the light output from the backlight panel 154. For example, the display device 500 can increase or decrease the contrast of the output image by adjusting the brightness and / or luminance of the LED light source included in the backlight panel 154. In an example embodiment, the display device 500 can control the color using the color filter and liquid crystal of the backlight panel 154.

[0086] The processor 110 may include an integrated circuit (IC) (e.g., a central processing unit (CPU)) 112 and / or a graphics processing unit (GPU) 114 for processing data based on one or more instructions, as well as a memory. For example, the CPU 112 may include an arithmetic and logic unit (ALU), a floating point unit (FPU), and a field programmable gate array (FPGA). The number of CPUs 112 may be one or more. For example, the CPU 112 may have a multi-core processor structure, such as a dual-core, quad-core, or hexa-core processor. For example, the GPU 114 may obtain an image to be output through the display panel 150 based on at least one application and / or system software executed by the CPU 112. In an example embodiment, the GPU 114 may generate a screen to be output through the display panel 150 by controlling a display driver IC (DDI) and / or a graphics memory included in the display panel 150 via the communication bus 130.

[0087] Figure 10 and Figure 11 : is a structure of a display device according to the present exemplary embodiment, and shows an arrangement relationship of each component including an LED light source based on a display panel structure.

[0088] Figure 10 is a schematic cross-sectional view of a display device (particularly, a display panel) according to an example embodiment of the inventive concept.

[0089] Reference Figure 10 The display device 500A according to this exemplary embodiment includes an image display panel 400A and a backlight unit 300A. The backlight unit 300A according to this exemplary embodiment is an example of a direct-lit backlight unit. The backlight unit 300A may include a light guide plate 330, a light source module 350A disposed on the lower surface of the light guide plate 330, and a first optical sheet 320 located between the light guide plate 330 and the light source module 350A. For example, the first optical sheet 320 may be a combination of various optical components such as a diffuser and a polarizer.

[0090] The light source module 350A may include a circuit board 210 and a plurality of LED light sources 100' mounted on the circuit board 210. The LED light source 100' may be the white light emitting device 100, 100A, or 100B according to the previous example embodiments. Figure 10 As shown, a plurality of LED light sources 100 ′ may be arranged in a plurality of rows and columns on the circuit board 210 .

[0091] The image display panel 400A may have a structure in which a second optical sheet 410, a liquid crystal layer 450, and a color filter layer 420 are sequentially arranged. The second optical sheet 410 may employ a combination of various optical components, such as a diffuser and a polarizer. The color filter layer 420 may include a transparent substrate, a color filter, and a common electrode. The color filter layer 420 may include a filter for selectively allowing light of a specific wavelength within the white light emitted from the backlight unit 300A to pass through the color filter layer 420. The liquid crystal layer 450 may include liquid crystals, and the electric field formed between the pixel electrodes and the common electrode rearranges the liquid crystals to adjust light transmittance. Light with adjusted light transmittance can pass through the color filters of the color filter layer 420 to display an image. The image display panel 400A may also include a driving circuit unit that processes image signals. In this manner, the white light emitted from the backlight unit 300A can pass through the second optical sheet 410 and the liquid crystal layer 450, and the transmitted white light can be incident on the color filter layer 420 to provide a desired color image.

[0092] Figure 11 is a schematic exploded perspective view of a display device according to an example embodiment of the inventive concept.

[0093] Reference Figure 11 , a display device 500B according to the present example embodiment may include a backlight unit 300B and an image display panel 400B.

[0094] The backlight unit 300B employed in this exemplary embodiment may include a bottom case 230, a reflector 340, a light guide plate 330, and a light source module 350B disposed on at least one side of the light guide plate 330. Similar to the previous exemplary embodiments, the light source module 350B may include a circuit board 210 and a plurality of LED light sources 100' arranged on the circuit board 210. The plurality of LED light sources 100' may be the white light emitting devices 100, 100A, or 100B according to the above exemplary embodiments. However, the LED light source 100' employed in this exemplary embodiment may be a side-view type light emitting device installed so that the light emitting window is located on the side.

[0095] Similar to the image display panel 400A in the previous exemplary embodiment, the image display panel 400B employed in this exemplary embodiment may include a plurality of first optical sheets 410, a liquid crystal layer 450, and a color filter layer 420. For example, the plurality of first optical sheets 410 may employ a combination of various optical members such as a diffusion sheet and a polarizing sheet.

[0096] As described above, the LED light source 100 ′ employed in the present exemplary embodiment may be provided as an excellent display light source that improves attention by controlling the secretion of melatonin and having a high color reproduction range.

[0097] By introducing a first blue LED chip and a second blue LED chip having different wavelengths, a light source for a display can be provided that can improve attention by controlling the secretion of melatonin while reducing BLH. In addition, the display light source according to the above exemplary embodiment can be improved by introducing a second wavelength conversion material (e.g., K2SiF6:Mn) having a smaller FWHM than other general phosphors. 4+ phosphor) to ensure high luminous efficiency while significantly improving the color gamut.

[0098] While example embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations may be made without departing from the scope of the inventive concept as defined by the appended claims.

Claims

1. A white light emitting device comprising: a first light emitting diode chip emitting light having a peak wavelength in a range of 425 nm to 455 nm; a second light emitting diode chip that emits light having a peak wavelength in a range of 460 nm to 470 nm; a first wavelength conversion material disposed at a travel path of light emitted from the first and second light-emitting diode chips and converting a portion of the emitted light into first light; as well as a second wavelength conversion material that is provided at a travel path of light emitted from the first and second light emitting diode chips and converts a portion of the emitted light into second light, wherein the first light, the second light, and the light emitted from each of the first LED chip and the second LED chip form white light as the output of the white light emitting device, wherein the first light has a peak wavelength within a range of 520 nm to 550 nm, and the second light has a peak wavelength within a range of 610 nm to 650 nm and a full width at half maximum of 50 nm or less, and The white light of the white light emitting device has a melanopic ratio of 1.3 or greater and a color gamut with a coverage of 90% or greater with respect to a DCI-P3 color gamut standard.

2. The white light emitting device according to claim 1, in, The white light has a melanopsin ratio of 1.35 or greater.

3. The white light emitting device according to claim 1, in, The blue light hazard value of the white light is 0.0018W / m 2 or smaller.

4. The white light emitting device according to claim 1, in, The luminous efficacy of the white light is 220W / m 2 or larger.

5. The white light emitting device according to claim 1, in, The color temperature of the white light is 19000K or higher.

6. The white light emitting device according to claim 1, in, The CIE 1931 color coordinates of the white light are (0.270<X<0.280, 0.235<Y<0.245).

7. The white light emitting device according to claim 1, in, The second wavelength conversion material includes a fluoride phosphor, and the composition formula of the fluoride phosphor is A x MF y :Mn 4+ ,and A is at least one selected from Li, Na, K, Rb and Cs, M is at least one selected from Si, Ti, Zr, Hf, Ge and Sn, and the composition formula satisfies 2≤x≤3 and 4≤y≤7.

8. The white light emitting device according to claim 1, further comprising: The main body has a recess, and the first light emitting diode chip and the second light emitting diode chip are arranged in the recess.

9. The white light emitting device according to claim 8, further comprising: a transparent resin that fills the recess, The first wavelength conversion material and the second wavelength conversion material are provided as particles and dispersed in the transparent resin.

10. The white light emitting device according to claim 1, further comprising: The main body has a first recess and a second recess, wherein the first light emitting diode chip and the second light emitting diode chip are respectively arranged in the first recess and the second recess.

11. The white light emitting device according to claim 10, further comprising: a transparent resin filling each of the first recess and the second recess, The first wavelength conversion material and the second wavelength conversion material are provided as particles and are dispersed in the transparent resin provided in the first concave portion and the second concave portion.

12. The white light emitting device according to claim 1, further comprising: A near-infrared phosphor is configured to convert a portion of light emitted from the first and second light-emitting diode chips into light having a peak wavelength of 740 nm to 900 nm.

13. The white light emitting device according to claim 12, in, The near-infrared phosphor includes a composition formula of Ca(Al 12-x-y ,Ga y )O 19 :xCr 3+ A phosphor wherein x satisfies 0.1≤x≤0.3 and y satisfies 3 or greater.

14. A white light emitting device comprising: a first light emitting diode chip emitting light having a peak wavelength in a range of 425 nm to 455 nm; a second light emitting diode chip that emits light having a peak wavelength in a range of 460 nm to 470 nm; a first wavelength conversion material disposed at a travel path of light emitted from the first and second light-emitting diode chips and converting a portion of the emitted light into first light having a peak wavelength within a range of 520 nm to 550 nm; as well as a second wavelength conversion material that is provided at a travel path of light emitted from the first and second light-emitting diode chips and converts a portion of the emitted light into second light having a peak wavelength within a range of 610 nm to 650 nm, wherein the first light, the second light, and the light emitted from each of the first LED chip and the second LED chip form white light as the output of the white light emitting device, Wherein, the second wavelength conversion material includes a fluoride phosphor, and the composition formula of the fluoride phosphor is A x MF y :Mn 4+ , wherein A is at least one selected from Li, Na, K, Rb and Cs, M is at least one selected from Si, Ti, Zr, Hf, Ge, Sn, and the composition formula satisfies 2≤x≤3 and 4≤y≤7, The blue light hazard value of the white light of the white light emitting device is 0.0018W / m 2 or smaller, and The white light has a color gamut with a coverage of 90% or greater with respect to a DCI-P3 color gamut standard.

15. The white light emitting device according to claim 14, in, The first wavelength conversion material includes at least one of (Ba, Sr) 2 SiO 4 : Eu and β-SiAlON: Eu.

16. The white light emitting device according to claim 14, in, The second wavelength conversion material further includes at least one of (Sr,Ca)AlSiN3:Eu and CaAlSiN3:Eu.

17. The white light emitting device according to claim 14, further comprising: a transparent resin covering the first light-emitting diode chip and the second light-emitting diode chip, The first wavelength conversion material and the second wavelength conversion material are dispersed in the transparent resin.

18. A display device comprising: an image display panel having a color filter layer including a red color filter, a green color filter, and a blue color filter; as well as a backlight unit disposed on a lower surface of the image display panel and having a plurality of light sources, Each of the plurality of light sources comprises a white light emitting device, and the white light emitting device comprises: a first light emitting diode chip emitting light having a peak wavelength in a range of 425 nm to 455 nm; a second light emitting diode chip that emits light having a peak wavelength in a range of 460 nm to 470 nm; a first wavelength conversion material that is provided at a travel path of light emitted from the first and second light emitting diode chips and converts a portion of the emitted light into first light; and a second wavelength conversion material that is provided at a travel path of light emitted from the first and second light emitting diode chips and converts a portion of the emitted light into second light, wherein the first light has a peak wavelength within a range of 520 nm to 550 nm, and the second light has a peak wavelength within a range of 610 nm to 650 nm and a full width at half maximum of 50 nm or less, wherein the first light, the second light, and the light emitted from each of the first LED chip and the second LED chip form white light as the output of the white light emitting device, wherein the white light from each of the plurality of light sources has a melanopic ratio of 1.3 or greater, and Wherein, a color gamut of light emitted from the image display panel has a coverage of 90% or greater with respect to a DCI-P3 color gamut standard.

19. The display device according to claim 18, in, The second wavelength conversion material includes a fluoride phosphor, and the composition formula of the fluoride phosphor is A x MF y :Mn 4+ ,and A is at least one selected from Li, Na, K, Rb and Cs, M is at least one selected from Si, Ti, Zr, Hf, Ge and Sn, and the composition formula satisfies 2≤x≤3 and 4≤y≤7.

20. The display device according to claim 18, in, The luminous efficacy of the white light is 220W / m 2 or larger.

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