Light emitting device

Abstract

The application provides a light emitting device. The light emitting device comprises a red light emitting unit, a green light emitting unit, a blue light emitting unit and a white light emitting unit. The red light emitting unit comprises a first blue light emitting chip and red phosphor, and the red light emitting unit emits red light with a main wavelength of 610-635 nm. The light emitting device is designed to comprise the red light emitting unit, the blue light emitting unit, the green light emitting unit and the white light emitting unit, and the structure of the red light emitting unit is designed, so that the light emitting device can realize atmosphere light and color temperature adjustment through four light emitting components, thereby saving cost.

Description

Technical Field

[0001] This invention relates to the field of display technology, and more particularly to a light-emitting device. Background Technology

[0002] As smart lighting fixtures permeate home lighting, people are demanding not only brightness adjustment but also dimming functions such as color temperature and ambient light adjustment.

[0003] In lighting fixtures, achieving ambient light adjustment requires the various colors of light involved in color color regulation to form a wider color gamut. This typically necessitates that each color have a narrower half-width and appropriate brightness. For color temperature adjustment, it's desirable for the different white light colors involved in color temperature control to have as continuous a spectrum as possible and a higher color rendering index as possible. Generally, the half-width of the various colors mixed to form white light should not be too narrow. Therefore, existing lighting fixtures typically use different components to independently achieve both ambient light and color temperature dimming functions. This usually requires at least five different color / color temperature light-emitting units, resulting in relatively high costs. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention provides a light-emitting device that only requires four light-emitting units to adjust the color temperature and ambient light of the light-emitting device, thereby reducing costs.

[0005] Specifically, in one aspect, an embodiment of the present invention provides a light-emitting device including a red light-emitting unit, a green light-emitting unit, a blue light-emitting unit, and a white light-emitting unit; wherein, the red light-emitting unit includes a first blue light-emitting chip and a red phosphor, and the main wavelength of the light emitted by the red light-emitting unit is between 610 and 635 nanometers.

[0006] On the other hand, another embodiment of the present invention provides a light-emitting device, including a red light-emitting unit, a green light-emitting unit and a blue light-emitting unit; wherein, the green light-emitting unit includes a third blue light-emitting chip and a narrow-wavelength green phosphor, and the main wavelength of the light emitted by the green light-emitting unit is between 535 and 550 nanometers.

[0007] In another aspect, a light-emitting device provided in another embodiment of the present invention includes a red light-emitting unit, a green light-emitting unit, and a blue light-emitting unit; wherein the red light-emitting unit includes a first blue light-emitting chip and a red phosphor, and the main wavelength of the light emitted by the red light-emitting unit is between 610 and 635 nanometers.

[0008] The above technical solution can have one or more of the following advantages or beneficial effects: By designing the light-emitting device to include a red light-emitting unit, a blue light-emitting unit, a green light-emitting unit, and a white light-emitting unit, and by designing the structure of the red light-emitting unit, the light-emitting device can achieve ambient light and color temperature adjustment through four light-emitting units, thus saving costs. Furthermore, based on this invention, reducing the number of white light-emitting units can also achieve a low-cost and high-brightness ambient light adjustment device. Attached Figure Description

[0009] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic diagram of the structure of a light-emitting device provided in an embodiment of the present invention.

[0011] Figure 2 This is a schematic diagram of the structure of another light-emitting device provided in an embodiment of the present invention.

[0012] Figure 3 This is a schematic diagram of the structure of another light-emitting device provided in an embodiment of the present invention.

[0013] Figure 4 This is a chromaticity diagram of a light-emitting device provided in an embodiment of the present invention.

[0014] Figure 5 This is a schematic diagram of the color gamut of a light-emitting device according to an embodiment of the present invention.

[0015] Figure 6 This is a schematic diagram of the spectrum of a light-emitting device provided in an embodiment of the present invention.

[0016] Figure 7 This is a schematic diagram of the spectrum of a red light-emitting unit in a light-emitting device according to an embodiment of the present invention.

[0017] Figure 8 This is a schematic diagram of another light-emitting device provided in an embodiment of the present invention.

[0018] Figure 9 This is a schematic diagram of the spectrum of the green light-emitting unit of a light-emitting device provided in an embodiment of the present invention.

[0019] Figure 10 This is another chromaticity diagram of a light-emitting device provided in an embodiment of the present invention.

[0020] Figure 11This is another spectral schematic diagram of a light-emitting device provided in an embodiment of the present invention.

[0021] Figure 12 This is a schematic diagram of the spectrum of another red light-emitting unit of the light-emitting device provided in an embodiment of the present invention.

[0022] Figure 13 This is a schematic diagram of the spectrum of another red light emitting unit of a light-emitting device provided in an embodiment of the present invention.

[0023] Figures 14A-14B This is a cross-sectional structural diagram of the red light emitting unit of a light-emitting device provided in an embodiment of the present invention. Detailed Implementation

[0024] The technical solution of one embodiment of the present invention 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 the invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] like Figure 1 As shown, the present invention provides a light-emitting device 10. The light-emitting device 10 is an RGBW lamp, a COB light source, or an LED, which has dimming functions such as adjusting ambient light and color temperature. Specifically, the light-emitting device 10 includes, for example, a red light-emitting unit 11 (R), a blue light-emitting unit 12 (B), a green light-emitting unit 13 (G), and a white light-emitting unit 14 (W). It is understood that the four light-emitting components mentioned above are controlled by independent circuits, that is, the four light-emitting components are controlled by different control circuits.

[0026] The green light-emitting unit 13 emits green light. Specifically, the green light-emitting unit may include at least one green light chip (not shown), and the main wavelength range of the green light chip is between 515 nm (nanometer) and 535 nm.

[0027] Recent research has revealed that the green light-emitting unit 13 may further include at least one third blue light-emitting chip and a narrow-wavelength green phosphor. Here, the narrow-wavelength green phosphor is a phosphor with a half-width of less than 70 nm that emits green light upon excitation. By selecting the third blue light-emitting chip and the green phosphor, the dominant wavelength of the light emitted by the green light-emitting unit is made to be between 535 and 550 nanometers. Specific selections will be detailed in other embodiments later.

[0028] The blue light-emitting unit 12 emits blue light. Specifically, the blue light-emitting unit may include at least one blue light chip (not shown), the dominant wavelength of which is between 460nm and 475nm. Recent research has found that blue light chips with a dominant wavelength between 455nm and 460nm can also be used in the blue light-emitting unit 12, for example, a blue light chip with a dominant wavelength of 475.5nm. In other words, the blue light-emitting unit may include at least one blue light chip, the dominant wavelength of which may be between 455nm and 475nm.

[0029] The red light-emitting unit 11 includes, for example, a first blue light-emitting chip and a red phosphor. Here, the red phosphor is a phosphor that emits red light upon excitation. Specifically, the dominant wavelength range of the first blue light-emitting chip is between 445 nm and 460 nm. The red phosphor is composed of a first red phosphor and a second red phosphor. Specifically, the first red phosphor is KSF(K2SiF6:Mn) 4+ The first red phosphor is a tetravalent manganese fluoride (KSF) phosphor. It is worth noting that KSF phosphor is yellow in color but emits red light when excited by blue light, hence it is also called a red phosphor. The second red phosphor is a long-wavelength nitride red phosphor. In this invention, long-wavelength nitride red phosphor mainly refers to nitride red phosphor with a peak wavelength greater than that of the first red phosphor, preferably with a peak wavelength between 635 nm and 660 nm. Nitride red phosphor is commonly referred to as CASN or 1113 phosphor, with a basic composition of CaAlSiN3:Eu. According to the latest research progress, the second red phosphor is not limited to long-wavelength nitride red phosphor. It can be used in combination with a certain amount of short-wavelength nitride red phosphor (i.e., nitride red phosphor with a peak wavelength less than that of the first red phosphor, preferably nitride red phosphor with a peak wavelength less than 635 nm). Therefore, based on the latest research progress, it can be preferably described that the second red phosphor is selected from nitride red phosphor. KSF phosphor has a very narrow spectral half-width, typically less than 30 nm, and exhibits a sharp peak. Therefore, KSF red phosphor has high brightness, which is beneficial for adjusting ambient light. The second red phosphor, compared to KSF phosphor, has a wider wavelength and a broader spectral half-width. It can be understood that a wider spectral half-width results in a more continuous spectrum when spectral overlap occurs, thus more closely resembling natural light and possessing a higher color rendering index, which is beneficial for adjusting color temperature. Therefore, a light-emitting device comprising the aforementioned red, blue, green, and white light-emitting units can achieve both ambient light and color temperature adjustment.

[0030] Recent research has revealed that the first red phosphor can be KSF phosphor, or it can be KGF(K2GeF6:Mn) phosphor. 4+ Phosphor, KTF(K2TiF6:Mn) 4+Phosphors, including KSF, KGF, and KTF, are all fluorosilicate materials excited by tetravalent manganese and can be collectively referred to as fluoride red phosphors. Their half-width is typically less than 30 nm.

[0031] The white light-emitting unit 14 can be composed of a second blue light-emitting chip with a main wavelength between 445nm and 460nm and a mixed phosphor. It is understood that the mixed phosphor, for example, can convert the blue light emitted from the second blue light-emitting chip into other colors, thereby mixing it with the blue light from the second blue light-emitting chip that is not absorbed by the mixed phosphor to form white light. Specifically, the mixed phosphor includes, for example, a third red phosphor. Specifically, the third red phosphor is a short-wavelength red phosphor (in this invention, it refers to a short-wavelength red phosphor with a peak wavelength less than 635nm), so that a portion of the blue light emitted by the second blue light-emitting chip passes through the third red phosphor and emits red light. Furthermore, the mixed phosphor also includes, for example, at least one of a green phosphor and a yellow-green phosphor. For example, the green phosphor is, for example, LuAG or GaYAG; the yellow-green phosphor is, for example, β-SiAlON, but this invention is not limited thereto. In this invention, the white light-emitting unit 14 uses short-wavelength red phosphor, preferably a nitride red phosphor with a peak wavelength between 605 nm and 620 nm. Nitride red phosphor is commonly referred to as CASN or 1113 phosphor, with a basic composition of CaAlSiN3:Eu. Depending on the wavelength selection, strontium (Sr) can be added appropriately, resulting in a composition of (Sr,Ca)AlSiN3:Eu, thereby shifting the peak wavelength of the phosphor towards shorter wavelengths. The color temperature of the white light-emitting unit is preferably 1800–3000 Kelvin (K). The following embodiments use 3000 Kelvin (K) as an example, but it is understood that the color temperature of the white light-emitting unit can also be other values. A white light-emitting unit 14 may include only one second blue light-emitting chip with a main wavelength between 445 and 460 nm, or it may include two or more chips.

[0032] Understandable, Figure 1The structure of the light-emitting device 10 shown is merely a simplified illustration of one embodiment of the present invention. It includes four light-emitting units, namely a red light-emitting unit 11, a blue light-emitting unit 12, a green light-emitting unit 13, and a white light-emitting unit 14. Each light-emitting unit includes at least one light-emitting chip. In one embodiment of the present invention, the light-emitting device 10 can be a luminaire that combines one or more sets of RGBW light-emitting devices such as LED beads (also known as Emitters, SMDs) together, or it can be a COB or luminaire that combines one or more sets of RGBW Chip Scale Packages (also known as CSPs) together. However, the four RGBW light-emitting units are not limited to four independent and detachable light-emitting devices; they can also be single light-emitting devices that are fixedly combined together, such as different parts of a single-cup or multi-cup LED bead. In summary, the red light-emitting unit 11, the blue light-emitting unit 12, the green light-emitting unit 13, and the white light-emitting unit 14 can be different light-emitting devices or different parts of the same light-emitting device.

[0033] Specifically, such as Figure 2 As shown, in one embodiment of the present invention, the light-emitting device 10 is, for example, a structure consisting of three bowls. For example, one bowl includes a red light-emitting unit 11, which consists of a first blue light-emitting chip and an encapsulating colloid containing long-wavelength nitride red phosphor. According to recent research, one bowl includes a red light-emitting unit 11, which consists of a first blue light-emitting chip and an encapsulating colloid containing fluoride red phosphor and nitride red phosphor, wherein the nitride red phosphor includes at least long-wavelength nitride red phosphor with a peak wavelength greater than that of the fluoride red phosphor. One bowl includes a white light-emitting unit 14, which consists of a second blue light-emitting chip and an encapsulating colloid containing mixed phosphor. One bowl also includes a blue light-emitting unit 12 and a green light-emitting unit 13. Since the blue light-emitting unit 12 and the green unit 13 do not require phosphor, only the encapsulating colloid 130, for example, made of silicone, needs to be added to the bowl to protect the chip. According to recent research, if in this embodiment the green light-emitting unit 13 uses a third blue light-emitting chip and narrow-wavelength green phosphor, then the green light-emitting unit 13 can be a chip-level package structure. It is understood that each bowl or cup may contain, for example, one or more light-emitting chips.

[0034] like Figure 3 As shown, in one embodiment of the invention, the light-emitting device 10 is, for example, a structure composed of four bowls / cups. Figure 2The difference lies in the structure: the blue light-emitting unit 12 and the green light-emitting unit 13 each occupy one bowl. Compared to the three-bowl structure, the four-bowl structure makes the light emitted by each bowl more concentrated, resulting in a better light mixing effect. At the same time, this support design also has a better heat dissipation effect, maintaining the stability of the thermal performance of each light-emitting unit.

[0035] An embodiment of the present invention provides a light-emitting device 10 with excellent ambient light color-tuning effect. It is understood that the higher the richness of the ambient light colors, the better the ambient light color-tuning effect, and the richness of the ambient light can be judged by the NTSC color gamut. For example... Figure 5 As shown, the NTSC color gamut of the light-emitting device 10 provided in one embodiment of the present invention is greater than or equal to 100% NTSC, and in this embodiment it can even reach 118.3% NTSC.

[0036] Specifically, Table 1 shows a light-emitting device 10 provided in an embodiment of the present invention, which achieves adjustment of color temperature and ambient light by adjusting the current ratio of the four units:

[0037] [Table 1] Parameter Table of Light-Emitting Device

[0038]

[0039] In Table 1, "30C" refers to a white light-emitting unit with a temperature of 3000K. The color temperature adjustment range of the light-emitting device 10 is between 2700K and 6500K. Within this color temperature adjustment range, the average color rendering index of the light-emitting device 10 can reach 90. It is understood that the color temperature of the light-emitting device provided in one embodiment of the present invention can also be adjusted to below 2700K or above 6500K, and the color temperature of the white light-emitting unit can also be 2000K or other color temperature values. "x" (or CIEx) and "y" (or CIEy) in the table refer to the chromaticity coordinate values ​​corresponding to the color temperature on the chromaticity diagram, i.e., the CIE diagram.

[0040] In this invention, at least three light-emitting units emit light simultaneously when adjusting the color temperature. Furthermore, as shown in Table 1, the device 10 can achieve different color temperatures by adjusting the current of the four light-emitting units. The light-emitting device 10 provided in one embodiment of the invention has a CRI (color rendering index) of approximately 90, exhibiting a high color rendering index. A higher color rendering index makes it easier for the human eye to distinguish various colors of objects. Prolonged exposure to light sources with poor color rendering can reduce the sensitivity of the cone cells in the human eye, leading to eye fatigue. The high color rendering index of this embodiment provides a better user experience.

[0041] Furthermore, such as Figure 4As shown, the color temperature curve of the light-emitting device 10 is L1. L1 is a curve, and the color temperature on the L1 curve is ( Figure 2 The triangle mentioned above falls at the ANSI center, that is, between two ellipses with similar color temperatures, conforming to the standard color. Therefore, the inventive device 10 achieves the adjustment of ambient light and color temperature. Existing technology uses warm white and cool white lighting to adjust color temperature: for example, if warm white is 2700K and cool white is 6500K, the emission curve is a straight line L2. Therefore, some color temperatures located between warm and cool white light do not fall within the two ellipses, resulting in a significant deviation from the standard color. Furthermore, both warm and cool white lighting must achieve a CRI of 90 to achieve the desired dimming effect, which places high demands on both the warm and cool white lights.

[0042] It should be noted that the current selection varies depending on the chip size. The data in Table 1 only demonstrates specific adjustments to the chip used in a particular embodiment to verify that the light-emitting device of the present invention can indeed achieve both color and color temperature adjustment while maintaining a high display index using only four light-emitting units. The current ratio is not intended to limit the technical scope of the present invention. A more generally applicable approach is to demonstrate the adjustment of each light-emitting unit in the light-emitting device of the present invention using the brightness ratio of each light-emitting unit. Using a white light unit brightness of 100 lm as a benchmark, Table 2 shows a light-emitting device 10 provided in one embodiment of the present invention. By designing the brightness ratio of the four light-emitting units, the color temperature and ambient light are adjusted.

[0043] [Table 2] Correspondence between color temperature and lumen parameters of the four light-emitting units in the light-emitting device

[0044]

[0045] In Table 2, "30C" refers to a white light-emitting unit at 3000K. "lm" is the physical unit describing luminous flux, a lumen, representing the total amount of visible light emitted by the light source per unit time. Taking a color temperature of 2700K for the light-emitting device 10 as an example, the red light emitted by the red light-emitting unit 11 is 10.7 lumens, the green light emitted by the green light-emitting unit 13 is 8.9 lumens, the blue light emitted by the blue light-emitting unit 12 is 0 lumens, and the white light emitted by the white light-emitting unit 14 is 100 lumens. It is understood that the specific values ​​in the table have a tolerance of ±50%. Although Table 2 only shows the color temperature variation of the light-emitting device 10 from 2700K to 6500K, the color temperature of the light-emitting device provided in this embodiment can be adjusted to below 2700K or above 6500K, and the color temperature of the white light-emitting unit can also be 2000K or other color temperature values.

[0046] Therefore, it can be seen that as the color temperature increases, the brightness of the red light emitted by the red light-emitting unit 11 in the light-emitting device 10 decreases with increasing color temperature. The brightness of the green light emitted by the green light-emitting unit 13 in the light-emitting device 10 increases with increasing color temperature. The brightness of the blue light emitted by the blue light-emitting unit in the light-emitting device 10 increases with increasing color temperature. It can be understood that "30C" refers to the white light-emitting unit being 3000K. It can be understood that although Tables 1 and 2 only show the color temperature variation of the light-emitting device 10 from 2700K to 6500K, the color temperature of the light-emitting device provided in the embodiments of the present invention can also be adjusted to be below 2700K or above 6500K, and the color temperature of the white light-emitting unit can also be 2000K or other color temperature values.

[0047] like Figure 6 As shown, the emission spectrum of the light-emitting device 10 has a first peak, a second peak, and a third peak. The first peak is located in the 615–635 nm wavelength range, which is the wavelength range in which the light-emitting device emits red light. The second peak is located in the 460–475 nm wavelength range, which is the wavelength range in which the light-emitting device 10 emits blue light. The third peak is located in the 515–535 nm wavelength range, which is the wavelength range in which the light-emitting device 10 emits green light. As the color temperature of the light-emitting device 10 increases, the half-width of the spectrum corresponding to the second peak increases with increasing color temperature. The intensity of the third peak increases with increasing color temperature, while the intensity of the fourth peak decreases with increasing color temperature.

[0048] In this embodiment of the invention, the red light-emitting unit 11 employs a technical solution combining a blue light-emitting chip with various red phosphors to emit specific red light. This allows it to both replace traditional red light chips in color temperature regulation and participate in the color temperature regulation of white lighting. More importantly, it does not require all the colors involved in color temperature regulation to reach a high CRI standard to achieve a final emitted light CRI of around 90. Specifically, by adjusting the ratio of the first and second red phosphors, the red light-emitting unit 11 is primarily used to emit red light with a main wavelength range between 615 and 635 nm. Recent research has found that adjusting the ratio of the first and second red phosphors to emit red light with a main wavelength range between 610 and 615 nm is also applicable to the light-emitting device of this invention. Excited by the blue light emitted from the first blue light-emitting chip, KSF red phosphor converts a portion of the blue light into narrow-wavelength red light with a peak wavelength of 630–634 nm, while long-wavelength nitride red phosphor converts a portion of the blue light into broad-wavelength red light with a peak wavelength of 635–660 nm. Because KSF red phosphor has a narrow spectral half-width (typically considered to be less than 30 nm), the spectrum of the red light-emitting unit has narrow peaks, resulting in high color purity and easier dimming of the red light excited by KSF red phosphor. Nitride red phosphor has good blue light absorption characteristics; therefore, long-wavelength nitride red phosphor can further convert and absorb the blue light emitted by the first blue light-emitting chip that was not absorbed by KSF, thus reducing the influence of the blue light emitted by the first blue light-emitting chip on the color purity of the red light emitted by the red light-emitting unit 10. According to the latest research progress, KSF red phosphor can be replaced by nitride red phosphors such as KGF and KTF. When using long-wavelength nitride red phosphor, short-wavelength nitride phosphor can be used in conjunction to reduce the absorption of narrow-wavelength red light by long-wavelength nitride phosphor and improve the brightness of the entire red light emitting unit 11.

[0049] like Figure 7 As shown in the schematic diagram of the emission spectrum of the red light-emitting unit 11, the emission spectrum of the red light-emitting unit 11 has a first peak in the 615-635 nm wavelength range. According to the latest research progress, the emission spectrum of the red light-emitting unit 11 can have a first peak in the 610-635 nm wavelength range. Let the intensity corresponding to the first peak be 1. The intensity of the red light-emitting unit 11 within the nanometer wavelength range, i.e., the dominant wavelength range of the first blue light-emitting chip, is less than or equal to 10% of the intensity corresponding to the first peak. Therefore, although the red light-emitting unit 11 emits light by exciting red phosphors from the first blue light-emitting chip, the emitted red light has high color purity and good brightness.

[0050] Furthermore, such as Figure 7As shown, in one embodiment of the present invention, the intensity of the red light-emitting unit 11 at a wavelength of 660 nm is 15-40% of the intensity corresponding to the first peak value. It is understood that when the intensity of the red light-emitting unit 11 at a wavelength of 660 nm is less than 15% or greater than 40%, it means that the light emitted by the first blue light-emitting chip is not sufficiently absorbed and converted, or is excessively absorbed and converted by the long-wavelength nitride red phosphor, resulting in a deterioration in brightness. It is also understood that in one embodiment of the present invention, the peak wavelength of the long-wavelength nitride red phosphor used is between 635 and 660 nm, for example, 650 nm. The emission spectrum of the red light-emitting unit 11 still has the aforementioned characteristics of a wavelength of 660 nm. This is mainly because the mutual interference between the emission spectra of different phosphors makes it difficult to measure the intensity at 650 nm. Therefore, this embodiment of the present invention uses the parameters measured in the 660 nm band as the control standard.

[0051] Since both the red light-emitting unit 11 and the white light-emitting unit 14 use red phosphors to excite red light, the color rendering index (CRI) of the white light-emitting unit 14 does not need to be too high in order to prevent the red light from interfering with each other and affecting the ambient light and color temperature adjustment of the light-emitting device 10. If the CRI of the white light-emitting unit 14 is high, the spectrum of the red light emitted by the third red phosphor in the white light-emitting unit 14 may excessively overlap with the spectrum of the red light excited by the red light-emitting unit, causing the overlapped spectrum to deviate from the requirements of dimming and color temperature adjustment. Therefore, it is recommended that the CRI of the white light-emitting unit 14 be less than or equal to 80. The half-width of the white light emitted by the white light-emitting unit 14 should be less than or equal to 110 nanometers. Specifically, in one embodiment, the CRI of the white light-emitting unit 14 is recommended to be around 70. Therefore, it can be understood that the light-emitting device 10 provided in this embodiment of the invention can achieve a high level of CRI even if the CRI of the white light-emitting unit 14 is low.

[0052] This invention, through its embodiment, designs a light-emitting device comprising a red light-emitting unit, a blue light-emitting unit, a green light-emitting unit, and a white light-emitting unit. The red light-emitting unit consists of KSF red phosphor with a very narrow half-wavelength and a sharp peak, a nitride red phosphor capable of absorbing blue light, and a first blue light-emitting chip. Thus, ambient light and color temperature can be adjusted using only four light-emitting units, saving costs. Furthermore, this embodiment of the light-emitting device also has the beneficial effect of achieving a high level of display index even when the white light-emitting unit has a low display index.

[0053] It is worth mentioning that although the above embodiments of the present invention are described using a light-emitting device composed of four different light-emitting units, those skilled in the art can reduce the number of white light-emitting units based on the present invention to achieve a low-cost and high-brightness ambient light adjustment device. The following embodiments, based on the latest research progress, only use an ambient light adjustment device with red, blue, and green light-emitting units as an example to introduce some research progress on red and green light-emitting units.

[0054] See Figure 8 The present invention also provides another light-emitting device 10, which may include, for example, a red light-emitting unit 11 (R), a blue light-emitting unit 12 (B), and a green light-emitting unit 13 (G). It is understood that the three light-emitting components mentioned above are controlled by independent circuits, that is, the three light-emitting components are controlled by different control circuits.

[0055] The blue light-emitting unit 12 emits blue light. Specifically, the blue light-emitting unit 12 may include at least one blue light chip (not shown), and the main wavelength of the blue light chip is between 455nm and 475nm.

[0056] In one specific embodiment of this invention, the green light-emitting unit 12 may, for example, include a third blue light-emitting chip and a narrow-band green phosphor. See also Figure 9 The peak wavelength of the light emitted by the green light-emitting unit 12 is between 520 and 530 nanometers, and the half-width of the spectrum is between 60 and 70 nanometers, thus making its dominant wavelength between 535 and 550 nanometers. Specifically, the wavelength of the third blue light-emitting chip is between 440 and 455 nanometers. The narrow-wavelength green phosphor can be selected from one or more of silicate phosphors, NBG phosphors, or β-SiAlON phosphors, for example. Preferably, the narrow-wavelength green phosphor is (Ba,Sr)₂SiO₄:Eu phosphor. By adjusting the amount of Ba and Sr in the (Ba,Sr)₂SiO₄:Eu phosphor, the half-width of the spectrum emitted by the green light-emitting unit 12 is between 60 and 70 nanometers. Considering the conversion efficiency of (Ba,Sr)2SiO4:Eu phosphor, the wavelength of the third blue light-emitting chip is selected to be between 440 and 455 nanometers. Since the wavelength of the third blue light-emitting chip is short, the conversion efficiency is improved, the corresponding brightness is also higher, and the amount of (Ba,Sr)2SiO4:Eu phosphor used is also reduced.

[0057] In existing technologies, common green light-emitting units typically use green light-emitting chips. Commonly used green light-emitting chips have a wavelength range of 515–530 nanometers. The dominant wavelength of 520 nanometers has x = 0.14 and y = 0.705, while the dominant wavelength of 523 nanometers has x = 0.15 and y = 0.727. For the dominant wavelength range of 515–530 nanometers, x ranges from 0.12 to 0.17, and y ranges from 0.68 to 0.75, resulting in a green light color purity of approximately 74%. To ensure consistent green light color, green light chips with a wavelength range of 5 nanometers are usually selected, which leads to higher costs.

[0058] In this embodiment, the green light-emitting unit 12 is configured to include a third blue light-emitting chip and a narrow-wavelength green phosphor. By selecting the green phosphor, the dominant wavelength of the emitted light is between 535 and 550 nm, x is between 0.25 and 0.3 nm, and y is between 0.6 and 0.63 nm. Although the NTSC color gamut is reduced to about 86% compared to the scheme using a green light-emitting chip, from the perspective of RGB ambient light color tuning, sacrificing a certain NTSC color gamut can improve the color consistency of green light while reducing the cost of selecting the chip. The color gamut value is still 86%, which is still a very viable option in the market.

[0059] It is worth mentioning that the aforementioned green light-emitting unit 12, configured to include a third blue light-emitting chip and narrow-band green phosphor, is not only applicable to RGB light-emitting devices, but also to devices such as... Figure 1 The RGBW light-emitting device shown.

[0060] In the RGBW light-emitting device, the green light-emitting unit 12 is configured to include a third blue light-emitting chip and a narrow-band green phosphor. The white light-emitting unit 14 preferably has a color temperature of 2500K, a color rendering index (CRI) < 80, preferably around 70, and emits a spectrum with a half-width of less than 110 nm, a peak wavelength of around 600 nm, and a CIExy color point centered at (0.487, 0.432). See also Figure 10 and Figure 11 From the perspective of RGBW light-emitting devices, by setting the green light-emitting unit 12 to include a third blue light-emitting chip and a narrow-wave green phosphor, the consistency of green light color can be guaranteed, the light efficiency can be improved, and the needs of customers with high light efficiency can be met. At the same time, the white light spectrum can be improved, making the white light spectrum more continuous.

[0061] In one specific embodiment of this invention, the red light-emitting unit 11 may, for example, include a first blue light-emitting chip and a red phosphor, and the dominant wavelength of the light emitted by the red light-emitting unit 11 may be, for example, between 610 and 635 nanometers. This configuration can improve the brightness of the light emitted by the red light-emitting unit 11 and make the purity of the light emitted by the red light-emitting unit 11 greater than or equal to 0.96. It is worth mentioning that the red light-emitting unit 11 in this embodiment is not only applicable to RGB lighting devices, but also to devices such as... Figure 1 The RGBW light-emitting device shown.

[0062] Specifically, see Figure 12 When the dominant wavelength of the light emitted by the red light-emitting unit 11 is required to be between 610 and 625 nm, one method to improve the brightness of the red light-emitting unit 11 is that the red phosphor may include, for example, a first red phosphor and a second red phosphor. The first red phosphor may be selected, for example, from fluoride red phosphor, and the second red phosphor is nitride red phosphor, which further includes long-wavelength nitride red phosphor and short-wavelength nitride red phosphor. The long-wavelength nitride red phosphor is a nitride red phosphor with a peak wavelength greater than that of the first red phosphor, such as CaAlSiN3:Eu or (Sr,Ca)AlSiN3:Eu with a peak wavelength between 635 and 660 nm; the short-wavelength nitride red phosphor is a nitride red phosphor with a peak wavelength less than that of the first red phosphor, such as (Sr,Ca)AlSiN3:Eu with a peak wavelength less than 635 nm.

[0063] The use of long-wavelength nitride red powder is to shift the dominant wavelength of the red light-emitting unit towards a longer wavelength relative to the peak wavelength of the fluoride, thereby ensuring that the dominant wavelength of the red light-emitting unit meets the requirements of a high color gamut. However, long-wavelength nitride red powder also absorbs light converted from fluoride red powder to some extent, resulting in a decrease in brightness. The greater the amount of long-wavelength nitride red powder used, the more pronounced this decrease in brightness becomes. If the amount of nitride red powder is insufficient, it is also insufficient to absorb the excess blue light from the first blue light-emitting chip that has not been absorbed by the fluoride red powder, thus failing to guarantee the purity of the light emitted by the red light-emitting unit 11. Therefore, when the dominant wavelength of the light emitted by the red light-emitting unit 11 is between 610 and 625 nanometers, a certain amount of short-wavelength nitride red powder can be used in conjunction with the long-wavelength nitride red powder. The wavelength difference between the long-wavelength and short-wavelength nitride red powder can be, for example, greater than 10 nanometers. By using two different peak wavelengths of nitride red powder, the red light spectrum becomes relatively symmetrical. By adjusting the ratio of long-wavelength and short-wavelength nitride red powder, the intensity of the red light emitted by the red light emitting unit 11 is such that the intensity at 700 nm / intensity at 600 nm is ≤. Table 3 shows examples of different ratios of long-wavelength and short-wavelength nitride red powder and their corresponding parameters. It can be clearly seen that this setting can improve the brightness of the light emitted by the red light emitting unit 11 and make the purity of the light emitted by the red light emitting unit 11 greater than or equal to 0.96.

[0064] Table 3

[0065] Nitrogen oxide red powder Flux lm％ X Y WD Blue light percentage Purity 640 13.35 100.0％ 0.6628 0.3162 616.9 0.61％ 0.938 640 11.62 87.0％ 0.6776 0.3127 618.2 0.14％ 0.971 640+620(1：0.2) 13.87 103.9％ 0.6737 0.3174 616.1 0.30％ 0.974 640+628(1：0.2) 13.64 102.1％ 0.6750 0.3154 617.0 0.27％ 0.972 640+628(1：0.1) 12.21 91.5％ 0.6785 0.3139 617.6 0.20％ 0.978 650+620(1：0.5) 14.96 112.0％ 0.6739 0.3163 616.6 0.24％ 0.971 650+628(1：0.5) 15.20 113.8％ 0.6769 0.3138 617.7 0.25％ 0.973

[0066] See Figure 13 When the dominant wavelength of the light emitted by the red light-emitting unit 11 is required to be between 625 and 635 nanometers, the red phosphor may, for example, include a first red phosphor and a second red phosphor. The first red phosphor may, for example, be selected from fluoride red phosphor, and the second red phosphor may, for example, be one or more nitride red phosphors, with a wavelength greater than 635 nanometers. Since the longer the wavelength of the nitride red phosphor, the further it is from the visual function and the lower its brightness, the intensity of the normalized spectrum at 660 nanometers is less than or equal to 40%.

[0067] To enhance the brightness of the red light-emitting unit 11, it can be manufactured, for example, using a layered dispensing process. Specifically, see [link to documentation]. Figure 14AThe red light-emitting unit 11 is defined with an upper region V1 located above the first blue light-emitting chip 111 and a peripheral region V2 surrounding the first blue light-emitting chip 111 and the upper region V1. A first red phosphor and a second red phosphor are dispersed in silicone to form a first red fluorescent adhesive layer and a second red fluorescent adhesive layer. The first red fluorescent adhesive layer covers, for example, the upper region and the periphery of the first blue light-emitting chip 111, and the second red fluorescent adhesive layer covers the first red fluorescent adhesive layer. Specifically, for example, a first red fluorescent adhesive layer 112a is formed on the upper region V1, and a first red fluorescent adhesive layer 112b is formed on the peripheral region V2; a second red fluorescent adhesive layer 113a is formed on the upper region V1, and a second red fluorescent adhesive layer 113b is formed on the peripheral region V2.

[0068] Specifically, for the red light emitting unit 11 requiring a main wavelength between 625 and 635 nanometers, in order to reduce the absorption of light emitted by the fluoride red powder by the long-wavelength nitride red powder and further improve brightness, the mass ratio of the first red phosphor to the second red phosphor is different in the upper region V1 and the peripheral region V2. Based on the uniformity of each layer of fluorescent adhesive in the dispensing process, it can be approximately considered that the volume ratio or cross-sectional thickness (average thickness or median thickness) ratio of the first red fluorescent adhesive 112 to the second red fluorescent adhesive 113 is different in the upper region V1 and the peripheral region V2. Based on the control of the concentration in the dispensing process, the above characteristics are usually intuitively reflected in the fact that, in the upper region V1 or the peripheral region V2, the thickness (average thickness or median thickness) of the first red fluorescent adhesive layer is greater than the thickness of the second red fluorescent adhesive layer. For example, see Figure 14A In the upper region V1, the thickness of the first red fluorescent adhesive layer 112a is less than the thickness of the second red fluorescent adhesive layer 113a; while in the peripheral region V2, the thickness of the first red fluorescent adhesive layer 112a is greater than the thickness of the second red fluorescent adhesive layer 113a.

[0069] See Figure 14B The first red fluorescent adhesive layer may, for example, only cover the first blue light-emitting chip 111, i.e., the first red fluorescent adhesive layer 112a is formed in the upper region V1. The second red fluorescent adhesive layer is disposed on the side of the first red fluorescent adhesive layer away from the first blue light-emitting chip 111, and the second red fluorescent adhesive layer is disposed in the peripheral region V2, i.e., the second red fluorescent adhesive layer 113a is formed in the upper region V1, and the second red fluorescent adhesive layer 113b is formed in the peripheral region V2. In the upper region V1, the thickness of the first red fluorescent adhesive layer 112a is greater than the thickness of the second red fluorescent adhesive layer 113a. In summary, for the red light-emitting unit 11 requiring a main wavelength between 625 and 635 nanometers, a further solution to improve brightness is to make the thickness of the first red fluorescent adhesive layer greater than the thickness of the second red fluorescent adhesive layer in either the upper region V1 or the peripheral region V2.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light-emitting device, characterized in that, It includes red light-emitting units, green light-emitting units, blue light-emitting units, and white light-emitting units; The red light emitting unit includes a first blue light emitting chip and a red phosphor, and the main wavelength of the light emitted by the red light emitting unit is between 610 and 635 nanometers. The emission spectrum of the red light emitting unit has a first peak in the 610-635 nm wavelength range, the emission spectrum of the light emitting device has a second peak in the 460-475 nm wavelength range, and the emission spectrum of the light emitting device has a third peak in the 515-535 nm wavelength range. The half-wavelength of the spectrum corresponding to the second peak increases with the increase of the color temperature of the light emitting device, the third peak increases with the increase of the color temperature of the light emitting device, and the first peak decreases with the increase of the color temperature of the light emitting device.

2. The light-emitting device as described in claim 1, characterized in that, The red phosphor includes a first red phosphor and a second red phosphor, wherein the first red phosphor is a fluoride red phosphor and the second red phosphor is a nitride red phosphor.

3. The light-emitting device as described in claim 2, characterized in that, The dominant wavelength of the light emitted by the red light emitting unit is between 610 and 625 nanometers, and the intensity of the red light spectrum emitted by the red light emitting unit at 700 nanometers / intensity at 600 nanometers is ≤110%.

4. The light-emitting device as described in claim 1, characterized in that, The intensity of the emission spectrum of the red light emitting unit in the 445-460 nm wavelength band is less than or equal to 10% of the intensity corresponding to the first peak value, and the intensity of the emission spectrum of the red light emitting unit at a wavelength of 660 nm is between 15% and 40% of the intensity corresponding to the first peak value.

5. The light-emitting device as claimed in claim 1, characterized in that, The green light-emitting unit includes at least one green light chip, and the main wavelength of the green light chip is between 515 and 535 nanometers.

6. The light-emitting device as claimed in claim 1, characterized in that, The green light-emitting unit includes a third blue light-emitting chip and a narrow-wavelength green phosphor. The main wavelength of the light emitted by the green light-emitting unit is between 535 and 550 nanometers.

7. The light-emitting device as described in claim 6, characterized in that, The narrow-wave green phosphor is a (Ba,Sr)2SiO4:Eu phosphor with a peak wavelength between 520 and 530 nm and a half-width between 60 and 70 nm.

8. The light-emitting device as claimed in claim 1, characterized in that, The blue light-emitting unit includes at least one blue light chip, and the main wavelength of the blue light chip is between 455 and 475 nanometers.

9. The light-emitting device as claimed in claim 1, characterized in that, The color temperature of the white light-emitting unit is between 1800 and 3000 Kelvin, and / or the color rendering index of the white light-emitting unit is less than 80, and / or the half-wavelength of the white light emitted by the white light-emitting unit is less than or equal to 110 nanometers.

10. A light-emitting device, characterized in that, It includes red light-emitting units, green light-emitting units, and blue light-emitting units; The green light-emitting unit includes a third blue light-emitting chip and a narrow-wavelength green phosphor. The dominant wavelength of the light emitted by the green light-emitting unit is between 535 and 550 nanometers. The emission spectrum of the red light-emitting unit has a first peak in the 610-635 nanometer band, the emission spectrum of the light-emitting device has a second peak in the 460-475 nanometer band, and the emission spectrum of the light-emitting device has a third peak in the 515-535 nanometer band. The half-wavelength of the spectrum corresponding to the second peak increases with the increase of the color temperature of the light-emitting device, the third peak increases with the increase of the color temperature of the light-emitting device, and the first peak decreases with the increase of the color temperature of the light-emitting device.

11. The light-emitting device as claimed in claim 10, characterized in that, The main wavelength of the third blue light-emitting chip is between 440 and 455 nanometers, and the narrow-wave green phosphor is a (Ba,Sr)2SiO4:Eu phosphor with a peak wavelength between 520 and 530 nanometers and a half-width between 60 and 70 nanometers.

12. A light-emitting device, characterized in that, It includes red light-emitting units, green light-emitting units, and blue light-emitting units; The red light emitting unit includes a first blue light emitting chip and a red phosphor, and the main wavelength of the light emitted by the red light emitting unit is between 610 and 635 nanometers. The emission spectrum of the red light emitting unit has a first peak in the 610-635 nm wavelength range, the emission spectrum of the light emitting device has a second peak in the 460-475 nm wavelength range, and the emission spectrum of the light emitting device has a third peak in the 515-535 nm wavelength range. The half-wavelength of the spectrum corresponding to the second peak increases with the increase of the color temperature of the light emitting device, the third peak increases with the increase of the color temperature of the light emitting device, and the first peak decreases with the increase of the color temperature of the light emitting device.

13. The light-emitting device as claimed in claim 12, characterized in that, The intensity of the emission spectrum of the red light emitting unit in the 445-460 nm wavelength band is less than or equal to 10% of the intensity corresponding to the first peak value, and the intensity of the emission spectrum of the red light emitting unit at a wavelength of 660 nm is between 15% and 40% of the intensity corresponding to the first peak value.

14. The light-emitting device as claimed in claim 12, characterized in that, The red phosphor includes a first red phosphor and a second red phosphor, wherein the first red phosphor is a fluoride red phosphor and the second red phosphor is a nitride red phosphor.

15. The light-emitting device as claimed in claim 14, characterized in that, The first red phosphor is dispersed in silicone to form a first red fluorescent adhesive layer, and the first red fluorescent adhesive layer is disposed on the first blue light-emitting chip. The second red phosphor is dispersed in silicone to form a second red fluorescent adhesive layer, and the second red fluorescent adhesive layer covers the first red fluorescent adhesive layer and the first blue light-emitting chip.

16. The light-emitting device as claimed in claim 14, characterized in that, The dominant wavelength of the light emitted by the red light emitting unit is between 610 and 625 nanometers. The second red phosphor includes long-wavelength nitride red phosphor with a peak wavelength greater than that of the first red phosphor and short-wavelength nitride red phosphor with a peak wavelength less than that of the first red phosphor. The intensity of the red light spectrum emitted by the red light emitting unit at 700 nanometers / intensity at 600 nanometers is ≤110%.

17. The light-emitting device as claimed in claim 15, characterized in that, The dominant wavelength of the light emitted by the red light-emitting unit is between 625 and 635 nanometers, and the wavelength of the nitride red powder is greater than 635 nanometers. The red light-emitting unit defines an upper region located above the first blue light-emitting chip and a peripheral region surrounding the first blue light-emitting chip and the upper region. In the upper region or the peripheral region, the thickness of the first red fluorescent adhesive layer is greater than the thickness of the second red fluorescent adhesive layer.

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