Light-emitting device

Abstract

A light-emitting device includes a circuit board, a plurality of semiconductor light-emitting elements, a strip-shaped wavelength conversion element, and a plurality of lenses. The plurality of semiconductor light-emitting elements are electrically joined to the circuit board and arranged along a longitudinal direction defined thereon. The strip-shaped wavelength conversion element is bent and fixed to the circuit board with its two long side edges thereof so as to span over the plurality of semiconductor light-emitting elements. Each lens is disposed on the circuit board and covers its corresponding semiconductor light-emitting element. Each semiconductor light-emitting element is configured to emit a first color light, and the first color light is diffused by its corresponding lens and then dispersedly projected onto the strip-shaped wavelength conversion element. A plurality of quantum dots in the strip-shaped wavelength conversion element absorb a part of the first color light passing through the strip-shaped wavelength conversion element and convert it into a second color light. The second color light is mixed with the remaining part of the first color light to form a third color light and then advances in a direction away from the circuit board.

Description

Technical Field

[0001] The present invention relates to a light-emitting device, and more particularly to a light-emitting device using a wavelength conversion element containing quantum dots with a smaller area. Background Art

[0002] As is well known, a liquid crystal display system displays images through a liquid crystal panel. However, the liquid crystal panel itself does not emit light and must achieve the light-emitting function through a so-called backlight device. Therefore, the backlight device is an important component of the liquid crystal display device.

[0003] Most current backlight devices use encapsulated semiconductor light-emitting diodes as the light-emitting source, and their architectures are generally divided into direct-lit backlight devices and edge-lit backlight devices. The direct-lit backlight device has advantages such as high light extraction efficiency, no need for a light guide plate, and fewer components, but also has disadvantages such as lower light uniformity and a thicker module. The direct-lit backlight device is divided into two types. The first type of direct-lit backlight device directly arranges light-emitting diodes in the lamp box. The main structure of the edge-lit backlight device is composed of a light-emitting source, a light guide plate, optical films (such as prism sheets, diffusion sheets, reflection sheets, etc.), a light source reflector, and an external structure (such as a frame, etc.). The wavelength conversion element with wavelength conversion function is an important element of the backlight device.

[0004] Currently, the wavelength conversion element with wavelength conversion function in the backlight device uses quantum dots to improve the display quality. Quantum dots are semiconductors in the form of nanocrystals that can provide alternative displays. The electronic properties of quantum dots are usually determined by the size and shape of the nanocrystals. Quantum dots of the same material but with different sizes can emit light of different colors when excited. More specifically, the wavelength of the light emitted by quantum dots varies with the size and shape of the quantum dots. In an example, larger quantum dots can emit light with a longer wavelength (e.g., red light), while smaller quantum dots can emit light with a shorter wavelength (e.g., blue or violet light). For example, quantum dots formed of cadmium selenide (CdSe) can be gradually modulated, from quantum dots with a diameter of 5 nm emitting in the red light region of the visible spectrum to quantum dots with a diameter of 1.5 nm emitting in the violet light region. By changing the size of the quantum dots, the entire visible light wavelength from about 460 nm (blue light) to about 650 nm (red light) can be emitted.

[0005] The application of quantum dot technology to liquid crystal display systems can significantly improve the color gamut and color vividness of liquid crystal display systems, and reduce power consumption. A liquid crystal display system using quantum dot technology, when combined with direct-lit backlight full array local dimming technology, can achieve a high dynamic contrast ratio and more details in bright and dark areas, resulting in a liquid crystal display effect with a vivid picture quality.

[0006] Regarding the prior art of wavelength conversion elements containing quantum dots, it is necessary to bond upper and lower water and gas barrier layers on the upper and lower surfaces of the wavelength conversion layer containing quantum dots to prevent the wavelength conversion layer from contacting air and water vapor. The wavelength conversion layer is formed by coating ultraviolet curable methyl methacrylate or thermosetting epoxy resin between the upper and lower water and gas barrier layers and then curing to form a transparent polymer substrate. Quantum dots are uniformly distributed within the transparent polymer substrate.

[0007] However, although backlight devices using wavelength conversion elements containing quantum dots have many advantages, the price of wavelength conversion elements containing quantum dots is still high, resulting in a high overall cost of backlight devices using wavelength conversion elements containing quantum dots. As the light-emitting area of the backlight device becomes larger, the problem of the high price of wavelength conversion elements containing quantum dots becomes more prominent. Summary of the Invention

[0008] Therefore, one technical problem to be solved by the present invention is to provide a light-emitting device using a wavelength conversion element containing quantum dots. The light-emitting device according to the present invention can be implemented as a strip light source or a surface light source. When implemented as a surface light source, the total area of the wavelength conversion elements containing quantum dots used in the light-emitting device according to the present invention is significantly reduced.

[0009] The light-emitting device according to the first preferred specific embodiment of the present invention includes a circuit board, a plurality of semiconductor light-emitting elements, a strip-shaped wavelength conversion element, and a plurality of lenses. The circuit board defines a longitudinal direction thereon. The plurality of semiconductor light-emitting elements are electrically joined to the circuit board and arranged along the longitudinal direction on the circuit board. The strip-shaped wavelength conversion element has two long sides. The strip-shaped wavelength conversion element is bent and fixed to the circuit board with its two long sides, thus spanning over the plurality of semiconductor light-emitting elements. The strip-shaped wavelength conversion element includes a wavelength conversion layer, a transparent upper water and gas barrier layer, and a transparent lower water and gas barrier layer. The wavelength conversion layer includes a transparent polymer substrate and a plurality of quantum dots. The plurality of quantum dots are uniformly distributed in the polymer substrate. The polymer substrate has an upper surface and a lower surface. The transparent upper water and gas barrier layer is joined to the upper surface of the polymer substrate. The transparent lower water and gas barrier layer is joined to the lower surface of the polymer substrate. Each lens corresponds to a semiconductor light-emitting element. Each lens is disposed on the circuit board and covers its corresponding semiconductor light-emitting element. Each semiconductor light-emitting element is used to emit a first color light, and is diffused by its corresponding lens and then scattered towards the strip-shaped wavelength conversion element. The plurality of quantum dots in the strip-shaped wavelength conversion element absorb a first part of the first color light passing through the strip-shaped wavelength conversion element and convert it into a second color light. The second color light is mixed with the remaining part of the first color light to form a third color light, and then advances in the direction away from the circuit board.

[0010] Furthermore, the light-emitting device according to the first preferred specific embodiment of the present invention further includes a reflective layer. The reflective layer is partially formed on the circuit board to expose the plurality of semiconductor light-emitting elements. The reflective layer is used to reflect the first color light incident on itself.

[0011] In a specific embodiment, each semiconductor light-emitting element includes a semiconductor light-emitting die, a transparent encapsulant, and a plurality of fluorescent powders. The transparent encapsulant covers the semiconductor light-emitting die. The plurality of fluorescent powders are uniformly distributed in the transparent encapsulant. Each semiconductor light-emitting die is used to emit a fourth color light and irradiate the transparent encapsulant. The plurality of fluorescent powders in the transparent encapsulant absorb a second part of the fourth color light passing through the transparent encapsulant and convert it into a fifth color light. The fifth color light is mixed with the remaining part of the fourth color light to form the first color light and then irradiate its corresponding lens.

[0012] The light-emitting device according to the second preferred specific embodiment of the present invention includes a circuit board, a plurality of semiconductor light-emitting dies, a reflective layer, a plurality of dimming layers, and a strip-shaped wavelength conversion element. The longitudinal direction is defined on the circuit board. The plurality of semiconductor light-emitting dies are electrically bonded to the circuit board and arranged along the longitudinal direction on the circuit board. The reflective layer is partially formed on the circuit board to expose the plurality of semiconductor light-emitting dies. Each dimming layer corresponds to a semiconductor light-emitting die and is formed on the top surface of its corresponding semiconductor light-emitting die. The strip-shaped wavelength conversion element has two long sides. The strip-shaped wavelength conversion element is bent and fixed to the circuit board with its two long sides, thereby spanning over the plurality of semiconductor light-emitting dies. The strip-shaped wavelength conversion element includes a wavelength conversion layer, a transparent upper water and oxygen barrier layer, and a transparent lower water and oxygen barrier layer. The wavelength conversion layer includes a transparent polymer substrate and a plurality of quantum dots. The plurality of quantum dots are uniformly distributed in the polymer substrate. The polymer substrate has an upper surface and a lower surface. The transparent upper water and oxygen barrier layer is bonded to the upper surface of the polymer substrate. The transparent lower water and oxygen barrier layer is bonded to the lower surface of the polymer substrate. Each semiconductor light-emitting die is used to emit a first color light, and the first color light passing through is attenuated by its corresponding dimming layer. The reflective layer is used to reflect the first color light incident on itself. A part of the first color light passing through the strip-shaped wavelength conversion element is absorbed by the plurality of quantum dots in the strip-shaped wavelength conversion element and converted into a second color light. The second color light is mixed with the remaining part of the first color light to form a third color light, and then advances in the direction away from the circuit board.

[0013] In a specific embodiment, the transparent polymer substrate can be formed of a transparent polymer material such as ultraviolet-curable methyl methacrylate or thermosetting epoxy resin.

[0014] The light-emitting device according to the third preferred specific embodiment of the present invention includes a circuit board, N groups of semiconductor light-emitting elements, N strip-shaped wavelength conversion elements, and a plurality of lenses, where N is an integer greater than 1. The circuit board defines N longitudinal directions parallel to each other thereon. Each group of semiconductor light-emitting elements corresponds to one longitudinal direction. Each group of semiconductor light-emitting elements is electrically joined to the circuit board and arranged along its corresponding longitudinal direction on the circuit board. Each strip-shaped wavelength conversion element corresponds to a group of semiconductor light-emitting elements and has two long sides. Each strip-shaped wavelength conversion element is bent and fixed to the circuit board with its two long sides, thereby spanning over the corresponding group of semiconductor light-emitting elements. Each strip-shaped wavelength conversion element includes a wavelength conversion layer, a transparent upper water and gas barrier layer, and a transparent lower water and gas barrier layer. The wavelength conversion layer includes a transparent polymer substrate and a plurality of quantum dots. The plurality of quantum dots are uniformly distributed in the polymer substrate. The polymer substrate has an upper surface and a lower surface. The transparent upper water and gas barrier layer is joined to the upper surface of the polymer substrate. The transparent lower water and gas barrier layer is joined to the lower surface of the polymer substrate. Each lens corresponds to a semiconductor light-emitting element. Each lens is disposed on the circuit board and covers its corresponding semiconductor light-emitting element. Each semiconductor light-emitting element is used to emit a first color light, and is diffused by its corresponding lens and then dispersed and emitted towards its corresponding strip-shaped wavelength conversion element. The plurality of quantum dots in each strip-shaped wavelength conversion element absorb a first part of the first color light passing through the strip-shaped wavelength conversion element and convert it into a second color light. The second color light is mixed with the remaining part of the first color light to form a third color light, and then advances in the direction away from the circuit board.

[0015] Furthermore, the light-emitting device according to the third preferred specific embodiment of the present invention further includes a reflective layer. The reflective layer is partially formed on the circuit board to expose a plurality of semiconductor light-emitting elements. The reflective layer is used to reflect the first color light incident on itself.

[0016] In a specific embodiment, each semiconductor light-emitting element includes a semiconductor light-emitting die, a transparent encapsulant, and a plurality of fluorescent powders. The transparent encapsulant encapsulates the semiconductor light-emitting die. The plurality of fluorescent powders are uniformly distributed in the transparent encapsulant. Each semiconductor light-emitting die is used to emit a fourth color light and emits it towards the transparent encapsulant. The plurality of fluorescent powders in the transparent encapsulant absorb a second part of the fourth color light passing through the transparent encapsulant and convert it into a fifth color light. The fifth color light is mixed with the remaining part of the fourth color light to form a first color light and then emitted towards its corresponding lens.

[0017] The light-emitting device according to the fourth preferred specific embodiment of the present invention includes a circuit board, N groups of semiconductor light-emitting dies, a reflective layer, a plurality of dimming layers, and N strip-shaped wavelength conversion elements, where N is an integer greater than 1. The circuit board defines N longitudinal directions parallel to each other thereon. Each group of semiconductor light-emitting dies corresponds to one longitudinal direction. Each group of semiconductor light-emitting dies is electrically bonded to the circuit board and arranged along the corresponding longitudinal direction on the circuit board. The reflective layer is partially formed on the circuit board to expose the N groups of semiconductor light-emitting dies. Each dimming layer corresponds to a semiconductor light-emitting die and is formed on the top surface of the corresponding semiconductor light-emitting die. Each strip-shaped wavelength conversion element corresponds to a group of semiconductor light-emitting dies and has two long sides. Each strip-shaped wavelength conversion element is bent and fixed to the circuit board with its two long sides, thereby spanning over the corresponding group of semiconductor light-emitting dies. Each strip-shaped wavelength conversion element includes a wavelength conversion layer, a transparent upper water and gas barrier layer, and a transparent lower water and gas barrier layer. The wavelength conversion layer includes a transparent polymer substrate and a plurality of quantum dots. The plurality of quantum dots are uniformly distributed in the polymer substrate. The polymer substrate has an upper surface and a lower surface. The transparent upper water and gas barrier layer is bonded to the upper surface of the polymer substrate. The transparent lower water and gas barrier layer is bonded to the lower surface of the polymer substrate. Each semiconductor light-emitting die is used to emit a first color light, and the first color light passing through is attenuated by the corresponding dimming layer. The reflective layer is used to reflect the first color light incident on itself. A part of the first color light passing through each strip-shaped wavelength conversion element is absorbed by the plurality of quantum dots in the strip-shaped wavelength conversion element and converted into a second color light. The second color light is mixed with the remaining part of the first color light to form a third color light, and then advances in the direction away from the circuit board.

[0018] In a specific embodiment, each strip-shaped wavelength conversion element has a first surface area. The circuit board has a second surface area. The ratio of the sum of the N first surface areas of the N strip-shaped wavelength conversion elements to the second surface area of the circuit board is equal to or less than 50%.

[0019] In a specific embodiment, the plurality of quantum dots can be formed by II-VI group compounds, III-V group compounds, IV-VI group compounds, IV group compounds, or a mixture of the above compounds.

[0020] Different from the prior art, the light-emitting device according to the present invention uses strip-shaped wavelength conversion elements containing quantum dots. Moreover, when implemented as a surface light source, the total area of the wavelength conversion elements containing quantum dots used in the light-emitting device according to the present invention can be significantly reduced.

[0021] The advantages and spirit of the present invention can be further understood through the following detailed description of the invention and the accompanying drawings. Description of the Drawings

[0022] Figure 1 External view of the light-emitting device according to the first preferred specific embodiment of the present invention;

[0023] Figure 2 Figure 1 Cross-sectional view of the light-emitting device along line A-A;

[0024] Figure 3 External view of the light-emitting device according to the second preferred specific embodiment of the present invention;

[0025] Figure 4 Figure 3 Cross-sectional view of the light-emitting device along line B-B;

[0026] Figure 5 External view of the light-emitting device according to the third preferred specific embodiment of the present invention;

[0027] Figure 6 Figure 5 Partial cross-sectional view of the light-emitting device along line C-C;

[0028] Figure 7 External view of the light-emitting device according to the fourth preferred specific embodiment of the present invention;

[0029] Figure 8 Figure 7 Partial cross-sectional view of the light-emitting device along line D-D.

[0030] Explanation of the reference numerals in the drawings:

[0031] 1: Light-emitting device

[0032] 10: Circuit board

[0033] 102: Substrate

[0034] 104: Conductive circuit

[0035] 12: Semiconductor light-emitting element

[0036] 120: Semiconductor light-emitting die

[0037] 1202: Bonding pad

[0038] 122: Package

[0039] 124: Fluorescent powder

[0040] 14: Wavelength conversion element

[0041] 140: Long side

[0042] 142: Wavelength conversion layer

[0043] 1420: Polymer substrate

[0044] 1421: Upper surface

[0045] 1422: Lower surface

[0046] 1424: Quantum dot

[0047] 144: Upper water and gas barrier layer

[0048] 146: Lower water and gas barrier layer

[0049] 16: Lens

[0050] 18: Reflective layer

[0051] 2: Light-emitting device

[0052] 20: Circuit board

[0053] 202: Substrate

[0054] 204: Conductive circuit

[0055] 22: Semiconductor light-emitting die

[0056] 220: Top surface

[0057] 222: Bonding pad

[0058] 24: Wavelength conversion element

[0059] 240: Long side

[0060] 242: Wavelength conversion layer

[0061] 2420: Polymer substrate

[0062] 2421: Upper surface

[0063] 2422: Lower surface

[0064] 2424: Quantum dot

[0065] 244: Upper water and gas barrier layer

[0066] 246: Lower water and gas barrier layer

[0067] 26: Dimming layer

[0068] 28: Reflective layer

[0069] 3: Light-emitting device

[0070] 30: Circuit board

[0071] 302: Substrate

[0072] 304: Conductive circuit

[0073] 32: Semiconductor light-emitting element

[0074] 320: Semiconductor light-emitting die

[0075] 3202: Bonding pad

[0076] 322: Package

[0077] 324: Fluorescent powder

[0078] 34: Wavelength conversion element

[0079] 340: Long side

[0080] 342: Wavelength conversion layer

[0081] 3420: Polymer substrate

[0082] 3421: Upper surface

[0083] 3422: Lower surface

[0084] 3424: Quantum dots

[0085] 344: Upper water and gas barrier layer

[0086] 346: Lower water and gas barrier layer

[0087] 36: Lens

[0088] 38: Reflective layer

[0089] 4: Light-emitting device

[0090] 40: Circuit board

[0091] 402: Substrate

[0092] 404: Conductive circuit

[0093] 42: Semiconductor light-emitting die

[0094] 420: Top surface

[0095] 422: Bonding pad

[0096] 44: Wavelength conversion element

[0097] 440: Long side

[0098] 442: Wavelength conversion layer

[0099] 4420: Polymer substrate

[0100] 4421: Upper surface

[0101] 4422: Lower surface

[0102] 4424: Quantum dots

[0103] 444: Upper water and gas barrier layer

[0104] 446: Lower water and gas barrier layer

[0105] 46: Light dimming layer

[0106] 48: Reflective layer

[0107] L: Longitudinal direction

[0108] R1: First color light

[0109] R2: Second color light

[0110] R3: Third color light

[0111] R4: Fourth color light

[0112] R5: Fifth color light Detailed implementation manners

[0113] Please refer to Figure 1 and Figure 2 , Figure 1 which schematically shows the structure of the light-emitting device 1 according to the first preferred specific embodiment of the present invention in an external view. Figure 2 Figure 1 The partial cross-sectional view of the light-emitting device 1 along the line A-A, thereby schematically showing the structure of the light-emitting device 1 according to the first preferred specific embodiment of the present invention. The light-emitting device 1 according to the first preferred specific embodiment of the present invention can be used as a strip light source.

[0114] As Figure 1 and Figure 2 shown, the light-emitting device 1 according to the first preferred specific embodiment of the present invention includes a circuit board 10, a plurality of semiconductor light-emitting elements 12, a strip-shaped wavelength conversion element 14, and a plurality of lenses 16.

[0115] The longitudinal direction L is defined on the circuit board 10. A plurality of semiconductor light-emitting elements 12 are electrically joined to the circuit board 10 and arranged along the longitudinal direction L on the circuit board 10.

[0116] The strip-shaped wavelength conversion element 14 has two long side edges 140. The strip-shaped wavelength conversion element 14 is bent and fixed to the circuit board 10 with its two long side edges 140, and thus spans above the plurality of semiconductor light-emitting elements 12. As Figure 2 shown, the cross-section of the strip-shaped wavelength conversion element 14 is generally in an arch shape.

[0117] The strip-shaped wavelength conversion element 14 includes a wavelength conversion layer 142, a transparent upper water and gas barrier layer 144, and a transparent lower water and gas barrier layer 146. The wavelength conversion layer 142 includes a transparent polymer substrate 1420 and a plurality of quantum dots 1424. The plurality of quantum dots 1424 are uniformly distributed within the polymer substrate 1420. The polymer substrate 1420 has an upper surface 1421 and a lower surface 1422. The transparent upper water and gas barrier layer 144 is joined to the upper surface 1421 of the polymer substrate 1420. The transparent lower water and gas barrier layer 146 is joined to the lower surface 1422 of the polymer substrate 1420. The upper water and gas barrier layer 144 and the lower water and gas barrier layer 146 are used to prevent the wavelength conversion layer 142 from contacting air and water vapor.

[0118] In a specific embodiment, the transparent polymer substrate 1420 can be formed of a transparent polymer material such as ultraviolet curable methyl methacrylate or thermosetting epoxy resin, but the present invention is not limited thereto.

[0119] In a specific embodiment, the plurality of quantum dots 1424 can be formed of II-VI group compounds, III-V group compounds, IV-VI group compounds, IV group compounds, or mixtures of the above compounds.

[0120] In a specific embodiment, the II-VI group compounds forming the plurality of quantum dots 1424 used in the present invention can be formed of CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or other II-VI group compounds.

[0121] In a specific embodiment, the III-V compound forming the multiple quantum dots 1424 used in the present invention may be formed by GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or a III-V compound.

[0122] In a specific embodiment, the IV-VI compound forming the multiple quantum dots 1424 used in the present invention may be formed by SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe, or other IV-VI compounds.

[0123] In a specific embodiment, the IV compound forming the multiple quantum dots 1424 used in the present invention may be formed by Si, Ge, SiC, SiGe, or other IV compounds.

[0124] Each lens 16 corresponds to a semiconductor light-emitting element 12. Each lens 16 is disposed on the circuit board 10 and covers its corresponding semiconductor light-emitting element 12.

[0125] Each semiconductor light-emitting element 12 is used to emit a first color light R1, and the first color light R1 is diffused by its corresponding lens 16 and then scattered toward the elongated wavelength conversion element 14. Multiple quantum dots in the elongated wavelength conversion element 14 absorb a first part of the first color light R1 passing through the elongated wavelength conversion element 14 and convert it into a second color light R2. The second color light R2 is mixed with the remaining part of the first color light R1 to form a third color light R3, and then advances in a direction away from the circuit board 10.

[0126] The function of the lens 16 is to reduce the forward light intensity of the first color light R1 emitted by the semiconductor light-emitting element 12, and at the same time expand the light-emitting angle of the semiconductor light-emitting element 12.

[0127] Furthermore, similarly as Figure 2As shown, the light-emitting device 1 according to the first preferred specific embodiment of the present invention further includes a reflective layer 18. The reflective layer 18 is partially formed on the circuit board 10 to expose a plurality of semiconductor light-emitting elements 12. The reflective layer 18 is used to reflect the first color light R1 incident on itself.

[0128] In a specific embodiment, as also Figure 2 shown, each semiconductor light-emitting element 12 includes a semiconductor light-emitting die 120, a transparent encapsulant 122, and a plurality of fluorescent powders 124. The transparent encapsulant 122 encapsulates the semiconductor light-emitting die 120. The plurality of fluorescent powders 124 are uniformly distributed in the transparent encapsulant 122. Each semiconductor light-emitting die 120 is used to emit a fourth color light R4 and emit it toward the transparent encapsulant 122. The plurality of fluorescent powders 124 in the transparent encapsulant 122 absorb a second portion of the fourth color light R4 passing through the transparent encapsulant 122 and convert it into a fifth color light R5. The fifth color light R5 is mixed with the remaining portion of the fourth color light R4 to form the first color light R1 and then emit it toward its corresponding lens 16. In Figure 2 the example shown, the semiconductor light-emitting die 120 has at least two pads 1202. The circuit board 10 includes a substrate 102 and conductive lines 104 formed on the substrate 102. The semiconductor light-emitting die 120 is soldered to the conductive lines 104 with its own pads 1202 to form an electrical connection. The semiconductor light-emitting die 120 can also form an electrical connection with the conductive lines 104 by wire bonding.

[0129] In another specific embodiment, each semiconductor light-emitting element 12 can be an unencapsulated semiconductor light-emitting die 120 (not shown in the figure), or an encapsulated semiconductor light-emitting die 120 without mixing fluorescent powders (not shown in the figure).

[0130] In an example, the semiconductor light-emitting element 12 emits blue light, and the quantum dots 1424 convert the absorbed blue light into yellow light. The light-emitting device 1 according to the first preferred specific embodiment of the present invention is a white light source.

[0131] In another example, the semiconductor light-emitting die 120 emits blue light, the fluorescent powder 124 converts the absorbed blue light into red light, the semiconductor light-emitting element 12 emits pinkish purple light, and the quantum dots 1424 convert the absorbed pinkish purple light into green light. The light-emitting device 1 according to the first preferred specific embodiment of the present invention is a white light source.

[0132] Please refer to Figure 3 and Figure 4 , Figure 3 which schematically shows the structure of the light-emitting device 2 according to the second preferred specific embodiment of the present invention in an external view. Figure 4 For Figure 3Partial cross-sectional view of the light-emitting device 2 along line B-B, thereby schematically showing the structure of the light-emitting device 2 according to the second preferred embodiment of the present invention. The light-emitting device 2 according to the second preferred embodiment of the present invention can be used as a strip light source.

[0133] As Figure 3 and Figure 4 shown, the light-emitting device 2 according to the second preferred embodiment of the present invention includes a circuit board 20, a plurality of semiconductor light-emitting dies 22, a reflective layer 28, a plurality of dimming layers 26, and a strip-shaped wavelength conversion element 24.

[0134] The circuit board 20 defines a longitudinal direction L thereon. The plurality of semiconductor light-emitting dies 22 are electrically joined to the circuit board 20 and arranged along the longitudinal direction L on the circuit board 20.

[0135] The reflective layer 28 is partially formed on the circuit board 20 to expose the plurality of semiconductor light-emitting dies 22. Each dimming layer 26 corresponds to a semiconductor light-emitting die 22 and is formed on the top surface 220 of its corresponding semiconductor light-emitting die 22.

[0136] The strip-shaped wavelength conversion element 24 has two long side edges 240. The strip-shaped wavelength conversion element 24 is bent and fixed to the circuit board 20 with its two long side edges 240, thereby spanning over the plurality of semiconductor light-emitting dies 22. As Figure 4 shown, the cross-section of the strip-shaped wavelength conversion element 24 is generally in the shape of an arch.

[0137] The strip-shaped wavelength conversion element 24 includes a wavelength conversion layer 242, a transparent upper water and gas barrier layer 244, and a transparent lower water and gas barrier layer 246. The wavelength conversion layer 242 includes a transparent polymer substrate 2420 and a plurality of quantum dots 2424. The plurality of quantum dots 2424 are uniformly distributed in the polymer substrate 2420. The polymer substrate 2420 has an upper surface 2421 and a lower surface 2422. The transparent upper water and gas barrier layer 244 is joined to the upper surface 2421 of the polymer substrate 2420. The transparent lower water and gas barrier layer 246 is joined to the lower surface 2422 of the polymer substrate 2420. The upper water and gas barrier layer 244 and the lower water and gas barrier layer 246 are used to prevent the wavelength conversion layer 242 from contacting air and water vapor.

[0138] In a specific embodiment, the transparent polymer substrate 2420 can be formed of a transparent polymer material such as ultraviolet curable methyl methacrylate or thermosetting epoxy resin, but the present invention is not limited thereto.

[0139] In a specific embodiment, the plurality of quantum dots 2424 can be formed of II-VI group compounds, III-V group compounds, IV-VI group compounds, IV group compounds, or a mixture of the above compounds.

[0140] In a specific embodiment, the II-VI group compounds forming the plurality of quantum dots 2424 used in the present invention may be formed by CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe or other II-VI group compounds.

[0141] In a specific embodiment, the III-V group compounds forming the plurality of quantum dots 2424 used in the present invention may be formed by GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb or other III-V group compounds.

[0142] In a specific embodiment, the IV-VI group compounds forming the plurality of quantum dots 2424 used in the present invention may be formed by SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe or other IV-VI group compounds.

[0143] In a specific embodiment, the IV group compounds forming the plurality of quantum dots 2424 used in the present invention may be formed by Si, Ge, SiC, SiGe or other IV group compounds.

[0144] Each semiconductor light-emitting die 22 is used to emit a first color light R1, and the first color light R1 passing through is attenuated by its corresponding dimming layer 26. The reflective layer 28 is used to reflect the first color light R1 incident on itself. A plurality of quantum dots 2424 in the strip-shaped wavelength conversion element 24 absorb a part of the first color light R1 passing through the strip-shaped wavelength conversion element 24 and convert it into a second color light R2. The second color light R2 is mixed with the remaining part of the first color light R1 to form a third color light R3, and then advances in a direction away from the circuit board 20.

[0145] In Figure 4 the illustrated example, the semiconductor light-emitting die 22 has at least two pads 222. The circuit board 20 includes a substrate 202 and conductive lines 204 formed on the substrate 202. The semiconductor light-emitting die 22 is soldered to the conductive lines 204 with its own pads 222 to form an electrical connection. The semiconductor light-emitting die 220 can also be electrically connected to the conductive lines 204 by wire bonding.

[0146] In an example, the semiconductor light-emitting die 22 emits blue light, and the quantum dots 2424 convert the absorbed blue light into yellow light. The light-emitting device 2 according to the second preferred specific embodiment of the present invention is a white light source.

[0147] Please refer to Figure 5 and Figure 6 , Figure 5 which schematically shows the structure of the light-emitting device 3 according to the third preferred specific embodiment of the present invention in an external view. Figure 6 is Figure 5 a partial cross-sectional view of the light-emitting device 3 along the C-C line in, thereby schematically showing the structure of the light-emitting device 3 according to the third preferred specific embodiment of the present invention. The light-emitting device 3 according to the third preferred specific embodiment of the present invention can be used as a surface light source.

[0148] As Figure 5 and Figure 6 shown, the light-emitting device 3 according to the third preferred specific embodiment of the present invention includes a circuit board 30, N groups of semiconductor light-emitting elements 32, N strip-shaped wavelength conversion elements 34, and a plurality of lenses 36, where N is an integer greater than 1.

[0149] The circuit board 30 defines N longitudinal directions L parallel to each other thereon. Each group of semiconductor light-emitting elements 32 corresponds to one longitudinal direction L. Each group of semiconductor light-emitting elements 32 is electrically joined to the circuit board 30 and arranged along its corresponding longitudinal direction L on the circuit board 30.

[0150] Each strip-shaped wavelength conversion element 34 corresponds to a group of semiconductor light-emitting elements 32 and has two long side edges 340. Each strip-shaped wavelength conversion element 34 is bent and fixed to the circuit board 30 by its two long side edges 340, and thus spans above the corresponding group of semiconductor light-emitting elements 32. As Figure 6 shown, the cross-section of each strip-shaped wavelength conversion element 34 is generally in the shape of an arch.

[0151] Each strip-shaped wavelength conversion element 34 includes a wavelength conversion layer 342, a transparent upper water and gas barrier layer 344, and a transparent lower water and gas barrier layer 346. The wavelength conversion layer 342 includes a transparent polymer substrate 3420 and a plurality of quantum dots 3424. The plurality of quantum dots 3424 are uniformly distributed in the polymer substrate 3420. The polymer substrate 3420 has an upper surface 3421 and a lower surface 3422. The transparent upper water and gas barrier layer 344 is joined to the upper surface 3421 of the polymer substrate 3420. The transparent lower water and gas barrier layer 346 is joined to the lower surface 3422 of the polymer substrate 3420. The upper water and gas barrier layer 344 and the lower water and gas barrier layer 346 are used to prevent the wavelength conversion layer 342 from contacting air and water vapor.

[0152] In a specific embodiment, the transparent polymer substrate 3420 can be formed of a transparent polymer material such as ultraviolet curable methyl methacrylate or thermosetting epoxy resin, but the present invention is not limited thereto.

[0153] In a specific embodiment, the plurality of quantum dots 3424 can be formed of II-VI group compounds, III-V group compounds, IV-VI group compounds, IV group compounds, or a mixture of the above compounds.

[0154] In a specific embodiment, the II-VI group compounds forming the plurality of quantum dots 3424 used in the present invention can be formed of CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or other II-VI group compounds.

[0155] In a specific embodiment, the III-V compound for forming the multiple quantum dots 3424 used in the present invention may be formed by GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or a III-V compound.

[0156] In a specific embodiment, the IV-VI compound for forming the multiple quantum dots 3424 used in the present invention may be formed by SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe, or other IV-VI compounds.

[0157] In a specific embodiment, the IV compound for forming the multiple quantum dots 3424 used in the present invention may be formed by Si, Ge, SiC, SiGe, or other IV compounds.

[0158] Each lens 36 corresponds to a semiconductor light-emitting element 32. Each lens 36 is disposed on the circuit board 30 and covers its corresponding semiconductor light-emitting element 32.

[0159] Each semiconductor light-emitting element 32 is used to emit a first color light R1, and the first color light R1 is diffused by its corresponding lens 36 and then dispersedly irradiated onto its corresponding strip-shaped wavelength conversion element 34. The multiple quantum dots 3424 in each strip-shaped wavelength conversion element 34 absorb a first part of the first color light R1 passing through the strip-shaped wavelength conversion element 34 and convert it into a second color light R2. The second color light R2 is mixed with the remaining part of the first color light R1 to form a third color light R3, and then advances in the direction away from the circuit board 30.

[0160] The function of the lens 36 is to reduce the forward light intensity of the first color light R1 emitted by the semiconductor light-emitting element 32, and at the same time expand the light-emitting angle of the semiconductor light-emitting element 32.

[0161] Further, similarly as Figure 6As shown, the light-emitting device 3 according to the third preferred specific embodiment of the present invention further includes a reflective layer 38. The reflective layer 38 is partially formed on the circuit board 30 to expose a plurality of semiconductor light-emitting elements 32. The reflective layer 38 is used to reflect the first color light R1 incident on itself.

[0162] In a specific embodiment, as also shown in Figure 6 As shown, each semiconductor light-emitting element 32 includes a semiconductor light-emitting die 320, a transparent encapsulant 322, and a plurality of fluorescent powders 324. The transparent encapsulant 322 encapsulates the semiconductor light-emitting die 320. The plurality of fluorescent powders 324 are uniformly distributed within the transparent encapsulant 322. Each semiconductor light-emitting die 320 is used to emit a fourth color light R4, which is incident on the transparent encapsulant 322. The plurality of fluorescent powders 324 within the transparent encapsulant 322 absorb a second portion of the fourth color light R4 passing through the transparent encapsulant 322 and convert it into a fifth color light R5. The fifth color light R5 is mixed with the remaining portion of the fourth color light R4 to form the first color light R1, which then shines on its corresponding lens 36. In Figure 6 In the example shown, the semiconductor light-emitting die 320 has at least two pads 3202. The circuit board 30 includes a substrate 302 and conductive traces 304 formed on the substrate 302. The semiconductor light-emitting die 320 is soldered to the conductive traces 304 with its own pads 3202 to form an electrical connection. The semiconductor light-emitting die 320 can also be electrically connected to the conductive traces 304 by wire bonding.

[0163] In another specific embodiment, each semiconductor light-emitting element 32 can be an unencapsulated semiconductor light-emitting die 320 (not shown in the figure), or an encapsulated semiconductor light-emitting die 320 without mixing in fluorescent powders (not shown in the figure).

[0164] In an example, the semiconductor light-emitting element 32 emits blue light, and the quantum dots 3424 convert the absorbed blue light into yellow light. The light-emitting device 3 according to the third preferred specific embodiment of the present invention is a white light source.

[0165] In another example, the semiconductor light-emitting die 320 emits blue light, the fluorescent powders 324 convert the absorbed blue light into red light, the semiconductor light-emitting element 32 emits pink-violet light, and the quantum dots 3424 convert the absorbed pink-violet light into green light. The light-emitting device 3 according to the third preferred specific embodiment of the present invention is a white light source.

[0166] In a specific embodiment, each strip-shaped wavelength conversion element 34 has a first surface area. The circuit board 30 has a second surface area. The ratio of the sum of the N first surface areas of the N strip-shaped wavelength conversion elements 34 to the second surface area of the circuit board 30 is equal to or less than 50%. That is to say, compared with the light-emitting device using a wavelength conversion element containing quantum dots in the prior art, the area of the wavelength conversion element 34 used in the light-emitting device 3 according to the third preferred specific embodiment of the present invention can be reduced by at least half.

[0167] Please refer to Figure 7 and Figure 8 , Figure 7 which schematically shows the structure of the light-emitting device 4 according to the fourth preferred specific embodiment of the present invention in an external view. The figure is Figure 7 a partial cross-sectional view of the light-emitting device 4 along the D-D line in, thereby schematically showing the structure of the light-emitting device 4 according to the fourth preferred specific embodiment of the present invention. The light-emitting device 4 according to the fourth preferred specific embodiment of the present invention can be used as a strip light source.

[0168] As Figure 7 and Figure 8 shown, the light-emitting device 4 according to the fourth preferred specific embodiment of the present invention includes a circuit board 40, N groups of semiconductor light-emitting die 42, a reflective layer 48, a plurality of dimming layers 46, and N strip-shaped wavelength conversion elements 44, where N is an integer greater than 1.

[0169] On the circuit board 40, N mutually parallel longitudinal directions L are defined. Each group of semiconductor light-emitting die 42 corresponds to one longitudinal direction L. Each group of semiconductor light-emitting die 42 is electrically bonded to the circuit board 40 and arranged along its corresponding longitudinal direction L on the circuit board 40.

[0170] The reflective layer 48 is partially formed on the circuit board 40 to expose the N groups of semiconductor light-emitting die 42. Each dimming layer 46 corresponds to one semiconductor light-emitting die 42 and is formed on the top surface 420 of its corresponding semiconductor light-emitting die 42.

[0171] Each strip-shaped wavelength conversion element 44 corresponds to one group of semiconductor light-emitting die 42 and has two long side edges 440. Each strip-shaped wavelength conversion element 44 is bent and fixed to the circuit board 40 with its two long side edges 440, and thus spans over its corresponding group of semiconductor light-emitting die 42. As Figure 8 shown, the cross-section of the strip-shaped wavelength conversion element 44 is generally in an arch shape.

[0172] Each strip-shaped wavelength conversion element 44 includes a wavelength conversion layer 442, a transparent upper water and gas barrier layer 444, and a transparent lower water and gas barrier layer 446. The wavelength conversion layer 442 includes a transparent polymer substrate 4420 and a plurality of quantum dots 4424. The plurality of quantum dots 4424 are uniformly distributed within the polymer substrate 4420. The polymer substrate 4420 has an upper surface 4421 and a lower surface 4422. The transparent upper water and gas barrier layer 444 is bonded to the upper surface 4421 of the polymer substrate 4420. The transparent lower water and gas barrier layer 446 is bonded to the lower surface 4422 of the polymer substrate 4420. The upper water and gas barrier layer 444 and the lower water and gas barrier layer 446 are used to prevent the wavelength conversion layer 442 from contacting air and water vapor.

[0173] In a specific embodiment, the transparent polymer substrate 4420 can be formed of a transparent polymer material such as ultraviolet curable methyl methacrylate or thermosetting epoxy resin, but the present invention is not limited thereto.

[0174] In a specific embodiment, the plurality of quantum dots 4424 can be formed of II-VI group compounds, III-V group compounds, IV-VI group compounds, IV group compounds, or a mixture of the above compounds.

[0175] In a specific embodiment, the II-VI group compounds forming the plurality of quantum dots 4424 used in the present invention can be formed of CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or other II-VI group compounds.

[0176] In a specific embodiment, the III-V compound for forming the multiple quantum dots 4424 used in the present invention may be formed of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or a III-V compound.

[0177] In a specific embodiment, the IV-VI compound for forming the multiple quantum dots 4424 used in the present invention may be formed of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe, or other IV-VI compounds.

[0178] In a specific embodiment, the IV compound for forming the multiple quantum dots 4424 used in the present invention may be formed of Si, Ge, SiC, SiGe, or other IV compounds.

[0179] Each semiconductor light-emitting die 42 is used to emit a first color light R1, and the first color light R1 passing through is attenuated by its corresponding dimming layer 46. The reflective layer 48 is used to reflect the first color light R1 incident on itself. A part of the first color light R1 passing through the strip-shaped wavelength conversion element 44 is absorbed by the multiple quantum dots 4424 in each strip-shaped wavelength conversion element 44 and converted into a second color light R2. The second color light R2 is mixed with the remaining part of the first color light R1 to form a third color light R3, and then advances in the direction away from the circuit board 40.

[0180] In Figure 8 In the illustrated example, each semiconductor light-emitting die 42 has at least two pads 422. The circuit board 40 includes a substrate 402 and conductive lines 404 formed on the substrate 402. The semiconductor light-emitting die 42 is soldered to the conductive lines 404 with its own pads 422 to form an electrical connection. The semiconductor light-emitting die 420 can also be electrically connected to the conductive lines 404 by wire bonding.

[0181] In an example, the semiconductor light-emitting die 42 emits blue light, and the quantum dots 4424 convert the absorbed blue light into yellow light. The light-emitting device 4 according to the fourth preferred embodiment of the present invention is a white light source.

[0182] In a specific embodiment, each strip-shaped wavelength conversion element 44 has a first surface area. The circuit board 40 has a second surface area. The ratio of the sum of the N first surface areas of the N strip-shaped wavelength conversion elements 44 to the second surface area of the circuit board 40 is equal to or less than 50%. That is to say, compared with the light-emitting device using a wavelength conversion element containing quantum dots in the prior art, the area of the wavelength conversion element 44 used in the light-emitting device 4 according to the fourth preferred embodiment of the present invention can be reduced by at least half.

[0183] Taking a 55-inch surface light source in the prior art using a wavelength conversion element containing quantum dots as a comparative example, the surface area of its wavelength conversion element is 696 mm (width) x 1225 mm (length). For the purpose of achieving the same light-emitting area, the light-emitting device according to the present invention can use 5 strip-shaped wavelength conversion elements with a width of 30 mm. The ratio of the sum of the surface areas of the 5 strip-shaped wavelength conversion elements of the light-emitting device according to the present invention to the surface area of the wavelength conversion element of the 55-inch surface light source in the prior art = 5 x 30 mm x 1225 mm / 696 mm x 1225 mm = 21%. It is sufficient to prove that when the light-emitting device according to the present invention is used as a surface light source, the area of the wavelength conversion element used therein can be reduced by at least half.

[0184] Using the light-emitting device according to the present invention as the backlight of a liquid crystal display system can improve the spectral RGB color purity of the backlight, and further improve the color rendering property of the liquid crystal display system to reach 100% of the standard set by the National Television System Committee (NTSC).

[0185] Through the detailed description of the above preferred specific embodiments, it is believed that it can be clearly understood that the light-emitting device according to the present invention uses strip-shaped wavelength conversion elements containing quantum dots. And when implemented as a surface light source, the total area of the wavelength conversion elements containing quantum dots used in the light-emitting device according to the present invention can be greatly reduced.

[0186] Through the detailed description of the above preferred specific embodiments, it is hoped that the features and spirit of the present invention can be more clearly described, rather than limiting the aspects of the present invention by the above-disclosed preferred specific embodiments. On the contrary, the purpose is to hope to cover various changes and equivalent arrangements within the aspects of the claims to be applied for the present invention. Therefore, the aspects of the claims applied for the present invention should be interpreted as broadly as possible according to the above description, so as to cover all possible changes and equivalent arrangements.

Claims

1. A light-emitting device, comprising: A circuit board, on which a longitudinal direction is defined; A plurality of semiconductor light-emitting elements, electrically joined to the circuit board and arranged along the longitudinal direction; An elongated wavelength conversion element, having two long side edges, the elongated wavelength conversion element being bent and fixed to the circuit board with the two long side edges so as to span over the plurality of semiconductor light-emitting elements, the elongated wavelength conversion element comprising: A wavelength conversion layer, comprising a transparent polymer substrate and a plurality of quantum dots, the plurality of quantum dots being uniformly distributed within the polymer substrate, the polymer substrate having an upper surface and a lower surface; A transparent upper moisture and gas barrier layer, joined to the upper surface of the polymer substrate; and A transparent lower moisture and gas barrier layer, joined to the lower surface of the polymer substrate; and A plurality of lenses, each lens corresponding to one semiconductor light-emitting element, each lens being disposed on the circuit board and covering its corresponding semiconductor light-emitting element, wherein each semiconductor light-emitting element is configured to emit a first color light and is diffused by its corresponding lens and then dispersedly emitted toward the elongated wavelength conversion element, the plurality of quantum dots within the elongated wavelength conversion element absorb a first portion of the first color light passing through the elongated wavelength conversion element and convert it into a second color light, and the second color light is mixed with the remaining portion of the first color light to form a third color light and then advances in a direction away from the circuit board.

2. The light-emitting device according to claim 1, further comprising a reflective layer, locally formed on the circuit board to expose the plurality of semiconductor light-emitting elements, the reflective layer being configured to reflect the first color light incident thereon.

3. The light-emitting device according to claim 2, wherein each semiconductor light-emitting element comprises: A semiconductor light-emitting die; A transparent encapsulant, encapsulating the semiconductor light-emitting die; and A plurality of fluorescent powders, uniformly distributed within the transparent encapsulant, wherein each semiconductor light-emitting die is configured to emit a fourth color light and emit it toward the transparent encapsulant, the plurality of fluorescent powders within the transparent encapsulant absorb a second portion of the fourth color light passing through the transparent encapsulant and convert it into a fifth color light, and the fifth color light is mixed with the remaining portion of the fourth color light to form the first color light and then emitted toward its corresponding lens.

4. A light-emitting device, comprising: A circuit board, on which a longitudinal direction is defined; A plurality of semiconductor light-emitting dies, electrically joined to the circuit board and arranged along the longitudinal direction; A reflective layer, locally formed on the circuit board to expose the plurality of semiconductor light-emitting dies; A plurality of dimming layers, each dimming layer corresponding to one semiconductor light-emitting die and formed on the top surface of its corresponding semiconductor light-emitting die; and An elongated wavelength conversion element, having two long side edges, the elongated wavelength conversion element being bent and fixed to the circuit board with the two long side edges so as to span over the plurality of semiconductor light-emitting dies, the elongated wavelength conversion element comprising: A wavelength conversion layer, comprising a transparent polymer substrate and a plurality of quantum dots, the plurality of quantum dots being uniformly distributed within the polymer substrate, the polymer substrate having an upper surface and a lower surface; A transparent upper water and oxygen barrier layer, bonded to the upper surface of the polymer substrate: and A transparent lower water and oxygen barrier layer, bonded to the lower surface of the polymer substrate, Wherein each semiconductor light-emitting die is configured to emit a first color light and the first color light passing therethrough is attenuated by its corresponding dimming layer, the reflective layer is configured to reflect the first color light incident thereon, the plurality of quantum dots within the elongated wavelength conversion element absorb a portion of the first color light passing through the elongated wavelength conversion element and convert it into a second color light, and the second color light is mixed with the remaining portion of the first color light to form a third color light and then advances in a direction away from the circuit board.

5. A light-emitting device, comprising: A circuit board, on which N mutually parallel longitudinal directions are defined, where N is an integer greater than 1; N groups of semiconductor light-emitting elements, each group of semiconductor light-emitting elements corresponding to one longitudinal direction, each group of semiconductor light-emitting elements being electrically bonded to the circuit board and arranged along its corresponding longitudinal direction; N elongated wavelength conversion elements, each elongated wavelength conversion element corresponding to a group of semiconductor light-emitting elements and having two long side edges, each elongated wavelength conversion element being bent and fixed to the circuit board with the two long side edges and thus spanning above its corresponding group of semiconductor light-emitting elements, each elongated wavelength conversion element comprising: A wavelength conversion layer, comprising a transparent polymer substrate and a plurality of quantum dots, the plurality of quantum dots being uniformly distributed within the polymer substrate, the polymer substrate having an upper surface and a lower surface; A transparent upper water and oxygen barrier layer, bonded to the upper surface of the polymer substrate: and A transparent lower water and oxygen barrier layer, bonded to the lower surface of the polymer substrate; and A plurality of lenses, each lens corresponding to a semiconductor light-emitting element, each lens being disposed on the circuit board and covering its corresponding semiconductor light-emitting element, Wherein each semiconductor light-emitting element is configured to emit a first color light and the first color light is diffused by its corresponding lens and then scattered toward its corresponding elongated wavelength conversion element, the plurality of quantum dots within each elongated wavelength conversion element absorb a first portion of the first color light passing through the elongated wavelength conversion element and convert it into a second color light, and the second color light is mixed with the remaining portion of the first color light to form a third color light and then advances in a direction away from the circuit board.

6. The light-emitting device according to claim 5, wherein each elongated wavelength conversion element has a first surface area, the circuit board has a second surface area, and the ratio of the sum of the N first surface areas of the N elongated wavelength conversion elements to the second surface area of the circuit board is equal to or less than 50%.

7. The light-emitting device according to claim 6, further comprising a reflective layer, which is locally formed on the circuit board to expose the N groups of semiconductor light-emitting elements, and the reflective layer is used to reflect the first color light incident on itself.

8. The light-emitting device according to claim 7, wherein each semiconductor light-emitting element comprises: a semiconductor light-emitting die; a transparent encapsulant that encapsulates the plurality of semiconductor light-emitting dies; and a plurality of fluorescent powders that are uniformly distributed in the transparent encapsulant, wherein each semiconductor light-emitting die is used to emit a fourth color light and the fourth color light is incident on the transparent encapsulant, the plurality of fluorescent powders in the transparent encapsulant absorb a second part of the fourth color light passing through the transparent encapsulant and convert it into a fifth color light, and the fifth color light is mixed with the remaining part of the fourth color light to form the first color light and then is incident on its corresponding lens.

9. A light-emitting device, comprising: a circuit board, on which N longitudinal directions parallel to each other are defined, where N is an integer greater than 1; N groups of semiconductor light-emitting dies, each group of semiconductor light-emitting dies corresponding to one longitudinal direction, and each group of semiconductor light-emitting dies is electrically bonded to the circuit board and arranged along its corresponding longitudinal direction; a reflective layer, which is locally formed on the circuit board to expose the N groups of semiconductor light-emitting dies; a plurality of dimming layers, each dimming layer corresponding to one semiconductor light-emitting die and formed on the top surface of its corresponding semiconductor light-emitting die; and N strip-shaped wavelength conversion elements, each strip-shaped wavelength conversion element corresponding to one group of semiconductor light-emitting dies and having two long sides, each strip-shaped wavelength conversion element is bent and fixed to the circuit board with the two long sides and thus spans above its corresponding group of semiconductor light-emitting dies, and each strip-shaped wavelength conversion element comprises: a wavelength conversion layer, comprising a transparent polymer substrate and a plurality of quantum dots, the plurality of quantum dots being uniformly distributed in the polymer substrate, and the polymer substrate having an upper surface and a lower surface; a transparent upper moisture and oxygen barrier layer, bonded to the upper surface of the polymer substrate; and a transparent lower moisture and oxygen barrier layer, bonded to the lower surface of the polymer substrate, wherein each semiconductor light-emitting die is used to emit a first color light and the first color light passing through is attenuated by its corresponding dimming layer, the reflective layer is used to reflect the first color light incident on itself, the plurality of quantum dots in each strip-shaped wavelength conversion element absorb a part of the first color light passing through the strip-shaped wavelength conversion element and convert it into a second color light, and the second color light is mixed with the remaining part of the first color light to form a third color light and then advances in a direction away from the circuit board.

10. The light-emitting device according to claim 9, wherein each strip-shaped wavelength conversion element has a first surface area, the circuit board has a second surface area, and the ratio of the sum of the N first surface areas of the N strip-shaped wavelength conversion elements to the second surface area of the circuit board is equal to or less than 50%.

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