Luminescent device and backlight source

Abstract

The utility model discloses a light-emitting device and a backlight source, the light-emitting device comprises a packaging support, a light-emitting chip and packaging glue, and the light-emitting chip is arranged on the packaging support; the light-emitting chip comprises an electroluminescent blue light quantum well layer, a photoluminescent green light quantum well layer and a substrate which are sequentially stacked, and the substrate is located on the side away from the packaging support; the packaging adhesive is arranged on the packaging bracket and covers the light-emitting chip; the packaging adhesive contains a red light wavelength conversion material. According to the invention, the problem of non-uniform color distribution caused by simultaneous arrangement of blue and green chips in an existing light-emitting device can be effectively relieved.

Description

Technical Field

[0001] This application relates to the field of semiconductor device technology, specifically to a light-emitting device and a backlight. Background Technology

[0002] LEDs (Light-Emitting Diodes) are widely used in LCD (Liquid Crystal Display) backlighting due to their advantages such as small size, high luminous efficiency, and long lifespan.

[0003] To improve the color gamut of a display, the LCD backlight spectrum needs to have purer and narrower red, green, and blue peaks at half maximum. The current solution is to package two chips, one for blue light and one for green light, together with a red phosphor during LED packaging. However, the light emitted by the two independent blue and green chips will have uneven color distribution when combined with a lens. Utility Model Content

[0004] This application provides a light-emitting device and a backlight that can effectively alleviate the problem of uneven color distribution in current light-emitting devices that simultaneously use two chips for blue and green light.

[0005] This application provides a light-emitting device, including:

[0006] Packaging bracket;

[0007] The light-emitting chip is disposed on a packaged substrate; the light-emitting chip includes an electroluminescent blue quantum well layer, a photoluminescent green quantum well layer and a substrate stacked sequentially, with the substrate located away from the packaged substrate;

[0008] The encapsulating adhesive is placed on the encapsulation bracket and covers the light-emitting chip; the encapsulating adhesive contains a red light wavelength conversion material.

[0009] In some embodiments of the light-emitting device, the light-emitting chip further includes a light emission adjustment structure layer disposed on a substrate;

[0010] The light emission adjustment structure layer is used to adjust the light emission ratio of blue light and green light.

[0011] In some embodiments of the light-emitting device, the light-emitting adjustment structure layer includes a plurality of stacked optical thin films, and the refractive indices of adjacent optical thin films are different.

[0012] In some embodiments of the light-emitting device, the light-emitting adjustment structure layer includes a plurality of alternatingly stacked first and second film layers, wherein the refractive indices of the first and second film layers are different.

[0013] In some embodiments of the light-emitting device, the light-emitting adjustment structure layer includes a first film layer and a second film layer stacked together, wherein the refractive indices of the first film layer and the second film layer are different.

[0014] In some embodiments of the light-emitting device, the light-emitting modulation structure layer includes a distributed Bragg reflection structure.

[0015] In some embodiments of the light-emitting device, the packaging bracket includes a metal pad, on which a plastic cup is disposed;

[0016] The metal pads include a first pad and a second pad, which are separated by insulating plastic. The bottom of the plastic bowl / cup exposes the first and second pads.

[0017] In some embodiments of the light-emitting device, the light-emitting chip further includes a first gallium nitride layer and a second gallium nitride layer, a first electrode is formed in the first gallium nitride layer, the first electrode is soldered to a first pad, and the first gallium nitride layer is located between the first electrode layer and the blue quantum well layer.

[0018] The second gallium nitride layer is located between the green quantum well layer and the substrate. A second electrode is formed in the second gallium nitride layer and is soldered to the second pad.

[0019] In some embodiments of the light-emitting device, encapsulating adhesive is filled into a plastic bowl.

[0020] This application also provides a backlight source, which includes a plurality of the above-described light-emitting devices.

[0021] The light-emitting device and backlight provided in this application include a packaging bracket, a light-emitting chip, and a packaging adhesive. The packaging adhesive contains a red light wavelength conversion material. The light-emitting chip includes an electroluminescent blue quantum well layer, a photoluminescent green quantum well layer, and a substrate stacked sequentially, so that the light-emitting chip can emit blue light and green light simultaneously. Only one light-emitting chip needs to be set when packaging to form the light-emitting device, which can effectively alleviate the problem of uneven color distribution caused by setting two chips, blue and green, at the same time. Attached Figure Description

[0022] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0023] Figure 1 This is a schematic diagram of the structure of the light-emitting device provided in the embodiments of this application.

[0024] Figure 2 This is a schematic diagram of the structure of the light-emitting chip in the light-emitting device provided in the embodiments of this application.

[0025] Figure 3 This is a schematic diagram of the light emission adjustment structure layer in the light-emitting device provided in the embodiments of this application.

[0026] Figure 4 This is a schematic diagram of the wavelength distribution of transmitted light in the light-emitting adjustment structure layer of the light-emitting device provided in the embodiments of this application.

[0027] Figure 5 The energy output curves of the light-emitting device provided in the embodiments of this application for different wavelengths of light are shown.

[0028] Figure label:

[0029] 1. Encapsulation bracket; 2. Light-emitting chip; 3. Encapsulating adhesive; 4. Red light wavelength conversion material;

[0030] 21. Blue quantum well layer; 22. Green quantum well layer; 23. Substrate; 24. First gallium nitride layer; 25. Second gallium nitride layer; 26. First electrode; 27. Second electrode; 28. Light emission modulation structure layer; 281. First film layer; 282. Second film layer. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Features thus defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this utility model, "multiple" means two or more, unless otherwise explicitly specified.

[0033] Please see Figure 1 This embodiment provides a light-emitting device, which includes a packaging bracket 1, a light-emitting chip 2, and a packaging adhesive 3. The light-emitting chip 2 is disposed on the packaging bracket 1, and the packaging adhesive 3 is disposed on the packaging bracket 1 and covers the light-emitting chip 2. The packaging adhesive 3 contains a red light wavelength conversion material 4.

[0034] The light-emitting chip 2 comprises a blue quantum well layer 21, a photoluminescent green quantum well layer 22, and a substrate 23 stacked sequentially. The substrate 23 is located away from the packaging support 1, while the blue quantum well layer 21 is located closer to the packaging support 1. This light-emitting device can emit both blue and green light simultaneously. Blue light is emitted by current injected into the blue quantum well layer 21, while green light is emitted after the green quantum well layer 22 absorbs a portion of the light emitted from the blue quantum well layer 21, performs photoconversion, and emits green light. Red light is emitted after the red wavelength conversion material 4 in the encapsulant 3 absorbs a portion of the blue light. In this embodiment, by simultaneously setting both the blue and green quantum well layers 21 and 22, the light-emitting device only requires one light-emitting chip 2 for packaging to meet the corresponding spectral requirements, effectively alleviating the problem of uneven color distribution caused by simultaneously setting two chips (blue and green) in current light-emitting devices.

[0035] Specifically, the packaging bracket 1 includes metal pads, on which a plastic cup 14 is disposed. The metal pads include a first pad 11 and a second pad 12, which are separated by insulating plastic 13. The bottom of the plastic cup 14 exposes the first pad 11 and the second pad 12. The light-emitting chip 2 and the encapsulating adhesive 3 are both disposed within the plastic cup 14. The light-emitting chip 2 is soldered to the first pad 11 and the second pad 12 respectively to establish an electrical connection; the encapsulating adhesive 3 fills the plastic cup 14. In this embodiment, by using a single chip to form the light-emitting device, costs can be saved while improving packaging efficiency.

[0036] Please refer to the following: Figure 2 The light-emitting chip 2 further includes a first gallium nitride layer 24 and a second gallium nitride layer 25. A first electrode 26 is formed in the first gallium nitride layer 24 and is soldered to a first pad 11. The first gallium nitride layer 24 is located between the first electrode layer 26 and the blue quantum well layer 21. The second gallium nitride layer 25 is located between the green quantum well layer 22 and the substrate 23. A second electrode 27 is formed in the second gallium nitride layer 25 and is soldered to a second pad 12.

[0037] For example, if the first electrode 26 is a P-type electrode and the second electrode 27 is an N-type electrode, then the first gallium nitride layer 24 is a P-type gallium nitride layer and the second gallium nitride layer 25 is an N-type gallium nitride layer.

[0038] In some embodiments, the light-emitting chip 2 further includes a light-emission adjustment structure layer 28, which is disposed on the substrate 23. In this embodiment, the light-emitting chip 2 is a flip chip, and the light-emission adjustment structure layer 28 is disposed on the substrate 23 side. This light-emission adjustment structure layer 28 is used to adjust the light emission ratio of blue light and green light. Figure 3As shown, light 51 is blue light emitted from the blue quantum well layer 21 that is not absorbed by the green quantum well layer 22 and reflected by the light emission adjustment structure. Light 52 is blue light emitted from the blue quantum well layer 21 that is absorbed after passing through the green quantum well layer 22. Light 53 is green light photoexcited by the green quantum well layer 22. Light 54 is green light emitted after the light emitted from the blue quantum well layer 21 passes through the green quantum well layer 22 for the first time without being absorbed, but is reflected by the light emission adjustment structure layer 28 and enters the green quantum well layer 22 for secondary excitation.

[0039] When the light-emitting chip 2 needs to increase green light, the light-emitting adjustment structure layer 28 increases the proportion of reflected blue light, allowing the reflected blue light to pass through the green quantum well for secondary excitation, thereby increasing the conversion efficiency of the light-emitting chip 2 for green light. Conversely, when it is necessary to reduce the proportion of green light, the light-emitting adjustment structure layer 28 reduces the proportion of blue light reflection, thereby reducing the secondary excitation of green quantum wells and ultimately reducing the conversion efficiency of green light.

[0040] As one embodiment, the light emission adjustment structure layer 28 includes multiple stacked optical thin films, with adjacent optical thin films having different refractive indices. In this embodiment, the light emission adjustment structure layer 28 is provided with optical thin film layers of different refractive indices. By changing the thickness of the light emission adjustment structure layer 28, the ratio of reflected and transmitted blue light to green light can be controlled, thereby achieving an ideal spectral modulation scheme.

[0041] In another embodiment, the light emission adjustment structure layer 28 includes multiple alternating layers of first film layers 281 and second film layers 282, wherein the refractive indices of the first film layers 281 and the second film layers 282 are different. That is, in this embodiment, only two film layers with different refractive indices are provided. By setting the thickness of the film layers, the ratio of reflected and transmitted blue light to green light can also be controlled, thereby achieving controllability of the emission spectrum.

[0042] Of course, in some embodiments, two film layers can also be provided, that is, the light emission adjustment structure layer 28 includes a first film layer 281 and a second film layer 282 stacked together, wherein the refractive index of the first film layer 281 and the refractive index of the second film layer 282 are different. The material of the first film layer 281 can be silicon dioxide, and the material of the second film layer 282 can be titanium dioxide.

[0043] As one embodiment, the light emission modulation structure layer 28 includes a distributed Bragg reflector structure; in this embodiment, the light emission modulation structure is a DBR reflector layer. Figure 4 As shown, by adjusting the thickness of the DBR reflective layer, it is possible to effectively reflect blue light below 460nm while transmitting light above 470nm. Figure 5 As shown, setting a DBR reflective layer in the light-emitting chip 2 can reduce blue light and increase green light energy output.

[0044] Among them, red light wavelength conversion materials are materials that can absorb light of a specific wavelength and convert it into red light. Common examples include phosphor materials and rare earth doped materials. In this embodiment, the red light wavelength conversion material 4 in the encapsulating adhesive 3 can be a red phosphor, so the proportion of red light emitted can be adjusted by adjusting the concentration of the red phosphor.

[0045] This application also provides a backlight source, which includes a plurality of the above-described light-emitting devices. Since the light-emitting devices have been described in detail above, they will not be described again here.

[0046] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0047] The light-emitting devices provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A light emitting device, characterized by, The application relates to a light emitting device. The light emitting device comprises: a package support; a light emitting chip arranged on the package support; the light emitting chip comprises, in sequence, an electroluminescent blue light quantum well layer, a photoluminescent green light quantum well layer and a substrate, and the substrate is located on the side far from the package support; 2. The light emitting device of claim 1, wherein a package glue arranged on the package support and covering the light emitting chip, wherein the package glue contains red light wavelength conversion material. The light emitting chip further comprises a light emitting adjusting structure layer arranged on the substrate; 3. The light emitting device of claim 2, wherein, the light emitting adjusting structure layer is used for adjusting the light emitting proportion of blue light and green light.

4. The light emitting device of claim 2, wherein, The light emitting adjusting structure layer comprises a plurality of optical films arranged in layers, and the refractive index of adjacent two layers of the optical films is different.

5. The light emitting device of claim 2, wherein, The light emitting adjusting structure layer comprises a plurality of first film layers and second film layers arranged in layers alternately, and the refractive index of the first film layers is different from that of the second film layers.

6. The light emitting device of claim 2, wherein The light emitting adjusting structure layer comprises a first film layer and a second film layer arranged in layers, and the refractive index of the first film layer is different from that of the second film layer.

7. The light-emitting device according to any one of claims 1 to 6, wherein The light emitting adjusting structure layer comprises a distributed Bragg reflection structure. The package support comprises a metal pad, and a plastic bowl cup is arranged on the metal pad; 8. The light emitting device of claim 7, wherein, the metal pad comprises a first pad and a second pad, the first pad and the second pad are arranged separately by insulating plastic, and the first pad and the second pad are exposed by the bottom of the plastic bowl cup. The light emitting chip further comprises a first gallium nitride layer and a second gallium nitride layer, a first electrode is formed in the first gallium nitride layer, the first electrode is welded on the first pad, and the first gallium nitride layer is located between the first electrode layer and the blue light quantum well layer; 9. The light emitting device of claim 7, wherein the first and second light emitting devices are arranged in a vertical stack. the second gallium nitride layer is located between the green light quantum well layer and the substrate, a second electrode is formed in the second gallium nitride layer, and the second electrode is welded on the second pad.

10. A backlight comprising: The package glue is filled in the plastic bowl cup. The application further relates to a light emitting device comprising a plurality of the light emitting devices as claimed in any one of claims 1 to 9.

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