Light emitting device
By using a layered fluorescent glue process in an LED light emitting device, combining ultra-narrow and medium-wide wave phosphor, the problem of difficulty in taking into account the purity and brightness of red light in the prior art is solved, and red with high color purity and high brightness is achieved Light effect, suitable for green lighting requirements, and improves product yield and operability.
Patent Information
- Application Number
- CN202411402789.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-09
- Publication Date
- 2025-01-10
AI Technical Summary
The existing LED white light packaging process is difficult to achieve high color purity and high brightness red light, especially pure red light, which requires a large amount of long-wave red powder to cause light efficiency and brightness to decrease, and excessive use of phosphors affects product miniaturization and yield.
Using layered fluorescent glue technology, using ultra-narrow wave phosphor and medium-wide wave phosphor combination, the first fluorescent glue layer is within the range of 630±2 nanometers, and the second fluorescent glue layer is within the range of 650 to 690 nanometers, passing through the luminescent chip The fluorescent glue layer is excited to increase the brightness of the red light of the light emitting device and the color purity reaches more than 99%.
It achieves the significant improvement of the brightness and light efficiency of the luminous device while ensuring high color purity, reduces the total amount of phosphor, is suitable for green lighting requirements, and improves the yield and operability of the product.
Smart Images
Figure CN119300579A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of lighting technology, and in particular to a light-emitting device. Background Art
[0002] In recent years, with the rapid development of the LED (light-emitting diode) packaging industry, the LED white light packaging process has become increasingly mature, but people's pursuit of special color light with high color purity and high brightness still has a lot of room for improvement. For example, to achieve pure red light, in addition to using red light chips, it is generally considered to use short-wave chips to excite red powder, but if the purity of red light is to be guaranteed (for example, greater than 96%), long-wave red powder (for example, red powder with an emission wavelength greater than 650 nanometers) must be used. The higher the red light purity requirement, the greater the demand for the wavelength and amount of red powder, which will cause the light efficiency and brightness of the entire light-emitting unit to decrease, which does not meet the requirements of green lighting. Summary of the invention
[0003] Therefore, in order to overcome at least some of the defects and shortcomings in the prior art, an embodiment of the present invention provides a light emitting device.
[0004] The light-emitting device provided by the embodiment of the present invention includes: a light-emitting chip; a first fluorescent glue layer surrounding the light-emitting chip; and a second fluorescent glue layer disposed on the first fluorescent glue layer and covering the light-emitting chip; at least one of the first fluorescent glue layer and the second fluorescent glue layer has a first emission wavelength in the range of 630±2 nanometers, and at least one of the first fluorescent glue layer and the second fluorescent glue layer has a second emission wavelength in the range of 650 to 690 nanometers. By exciting the specific first fluorescent glue layer and the second fluorescent glue layer by the light-emitting chip, the red light emitted by the light-emitting device has a higher brightness, and the color purity can achieve more than 99%. BRIEF DESCRIPTION OF THE DRAWINGS
[0005] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use 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 ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.
[0006] Figure 1 A schematic structural diagram of a light emitting device provided in an embodiment of the present invention.
[0007] Figure 2 Another schematic diagram of the structure of the light emitting device provided by the embodiment of the present invention.
[0008] Figure 3 A spectrum diagram of the light-emitting device provided in an embodiment of the present invention. DETAILED DESCRIPTION
[0009] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments described in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.
[0010] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, top, bottom, horizontal, and vertical) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.
[0011] In the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.
[0012] See also Figure 1 and Figure 2 A light-emitting device 10 provided in an embodiment of the present invention is a red light-emitting device, which may include, for example: a light-emitting chip 100 , a first fluorescent glue layer 200 and a second fluorescent glue layer 300 .
[0013] The light-emitting chip 100 may be, for example, a purple chip, a blue chip, or a green chip. The present invention takes a blue chip that has better excitation efficiency for most red phosphors as an example. The wavelength of the light-emitting chip 100 may be, for example, 450 to 460 nanometers. The first fluorescent glue layer 200 may, for example, surround the light-emitting chip 100, and specifically, may, for example, surround the side wall of the light-emitting chip 100. The second fluorescent glue layer 300 is disposed on the first fluorescent glue layer 200 and covers the light-emitting chip 100. That is, the first fluorescent glue layer 200 is located in the lower layer, and the second fluorescent glue layer 300 is located in the upper layer.
[0014] At least one of the first fluorescent glue layer 200 and the second fluorescent glue layer 300 has a first emission wavelength in the range of 630±2 nanometers, and at least one of the first fluorescent glue layer 200 and the second fluorescent glue layer 300 has a second emission wavelength in the range of 650-690 nanometers. This makes it possible for the light emission spectrum of the light emitting device 10 to have a peak inflection point in the range of 630±2 nanometers and another peak inflection point in the range of 650-690 nanometers. This can ensure that the brightness and purity of the light emitting device 10 can be taken into account to a certain extent.
[0015] See Table 1, which is a data comparison of the light-emitting device 10 provided by the prior art and the present embodiment. The prior art is to simply use a short-wave light-emitting chip to excite a long-wave red powder (for example, red powder with an emission wavelength greater than 650 nanometers) to achieve a relatively high color purity (for example, 99%). The color coordinates are (0.7063, 0.2900), and the purity reaches 0.989, close to 99%, but the brightness is only 10.43, and in a large amount of data, the purity mean value of the light-emitting device manufactured using this technology within the three-step color tolerance range can only be guaranteed to be greater than 97%. In a specific embodiment, the light-emitting device 10 of the present invention uses the same light-emitting chip and operating current density to achieve the same color coordinates and purity, and the brightness can be 13.10, and the light efficiency and brightness are significantly improved; and the purity mean value of the light-emitting device 10 manufactured using this technology within the three-step color tolerance range can be guaranteed to be greater than 99%.
[0016] Table 1
[0017]
[0018] Specifically, in one implementation of this embodiment, the first fluorescent glue layer 200 may include, for example, an ultra-narrow wave fluorescent powder with an emission wavelength of 630±2 nanometers, and the half-wave width range of the ultra-narrow wave fluorescent powder is less than 30 nanometers. The second fluorescent glue layer 300 may include, for example, a medium-wide wave fluorescent powder, and the half-wave width range of the medium-wide wave fluorescent powder is 50 to 70 nanometers. In this embodiment, the ultra-narrow wave fluorescent powder may be, for example, a fluoride fluorescent powder, specifically, KSF (K2SiF6:Mn 4+ )Phosphor, KGF(K2GeF6:Mn 4+ )Phosphor, KTF(K2TiF6:Mn 4+) phosphors, etc. The medium-wide wave phosphors can be, for example, selected from nitride phosphors, silicates, sulfides, a-SiAlON phosphors, etc. In the present embodiment, the second fluorescent glue layer 300 can, for example, use one medium-wide wave phosphor, or can use two or more medium-wide wave phosphors of different wavelengths mixed in a certain proportion. When the second fluorescent glue layer 300 uses only one medium-wide wave phosphor, the emission wavelength range of the medium-wide wave phosphor is preferably 650 to 690 nanometers. When the second fluorescent glue layer 300 chooses to use two or more medium-wide wave phosphors of different wavelengths mixed in a certain proportion, the emission wavelength range of the medium-wide wave phosphor that can be selected is 630 to 700 nanometers, and at least one of the medium-wide wave phosphors has an emission wavelength range of more than 650 nanometers. In other words, although the emission wavelength of the second fluorescent glue layer 300 is mentioned above to be 650-690 nanometers, the selection of medium-wideband fluorescent powder is not limited to fluorescent powder with an emission wavelength of 650-690 nanometers. The second fluorescent glue layer 300 may include a variety of fluorescent powders with an emission wavelength of 630-700 nanometers. When the peak wavelength of the emission spectrum of the fluorescent glue after the different fluorescent powders are mixed is between 650-690 nanometers after being excited, it is the second fluorescent glue layer 300 with an emission wavelength of 650-690 nanometers described in the present invention. If the emission wavelength of the second fluorescent glue layer 300 is too short, the color purity will be reduced, and if the wavelength is too long, the brightness will be affected. In another implementation of the present embodiment, the first fluorescent glue layer 200 may, for example, include medium-wideband fluorescent powder with an emission wavelength in the range of 650-690 nanometers, and the second fluorescent glue layer 300 may, for example, include ultra-narrowband fluorescent powder with an emission wavelength of 630±2 nanometers. Of course, the present embodiment is not limited to this. The first phosphor layer 200 and the second phosphor layer 300 include a medium-wide wave phosphor with an emission wavelength in the range of 650 to 690 nanometers and an ultra-narrow wave phosphor with an emission wavelength of 630±2 nanometers. For the convenience of explanation, the following is only described with the best implementation method at present. By combining the ultra-narrow wave phosphor with an emission wavelength of 630±2 nanometers with the phosphor with an emission wavelength of 630 to 700 nanometers, the intensity of the orange-yellow light part of the luminous spectrum of the light-emitting device 100 near the red light can be controlled, and the purity of the red light can be improved. Furthermore, the amount of ultra-narrow wave phosphor is preferably 20% to 70% of the total weight of all phosphors, and the brightness of the red light can be improved.
[0019] Conventional phosphor conversion LED lighting products are to mix all phosphors with silica gel into fluorescent glue and then directly encapsulate them on LED light-emitting chips. Light-emitting chips, such as blue light chips, excite fluorescent glue and emit mixed light. However, for special color light with purity requirements, such as pure red light, red powder with a larger emission wavelength is required to ensure the color point of red light, and a larger amount of red powder is required to absorb all the light emitted by the light-emitting chip to ensure the final color purity. The longer the emission wavelength of red or orange phosphors, the worse the luminous efficiency. The higher the red light purity requirement, the greater the demand for the wavelength and amount of red powder. As the demand for the wavelength and amount of red light increases, the light efficiency and brightness of the entire light-emitting unit will drop sharply, which does not meet the requirements of green lighting. Based on the requirements of product miniaturization, excessive phosphor dosage may cause operational difficulties and affect product yield. The light-emitting device 10 provided in this embodiment uses a layered dispensing process to separate phosphors with different characteristics into fluorescent glue, and is set in a specific manner to reduce the total amount of phosphors used and improve the brightness of the light-emitting device while ensuring color purity.
[0020] See also Figure 1 , the first fluorescent glue layer 200 is arranged around the light emitting chip 100, and the first fluorescent glue layer 200 does not cover the upper surface of the light emitting chip 100. Specifically, the upper surface of the light emitting chip 10 may, for example, not be provided with the first fluorescent glue layer 200. In this embodiment, the light emitting device 10 may, for example, further include a support cup 400, the light emitting chip 100 is arranged at the bottom of the support cup 400, and the first fluorescent glue layer 200 and the second fluorescent glue layer 300 are both arranged in the support cup 400. The first fluorescent glue layer 200 is arranged around the light-emitting chip 100. Based on the current dispensing process, the first fluorescent glue layer 200 may climb along the cup wall of the support bowl 400, so that the horizontal height of the part of the first fluorescent glue layer 200 close to the cup wall may exceed the upper surface of the light-emitting chip 100. However, in this embodiment, the longitudinal space where the chip is located is taken as the solid crystal area S1, excluding the part of the first fluorescent glue layer 200 climbing along the cup wall of the support bowl 400, the horizontal height of the first fluorescent glue layer 200 is less than or equal to the thickness of the light-emitting chip 100.
[0021] See also Figure 2, the first fluorescent glue layer 200 can also be, for example, arranged around the light-emitting chip 100 and cover the upper surface of the light-emitting chip 100, and the thickness of the first fluorescent glue layer 200 covering the upper surface of the light-emitting chip 100 is less than or equal to 25% of the thickness of the light-emitting chip 100, and further, the thickness of the first fluorescent glue layer 200 covering the upper surface of the light-emitting chip 100 is less than or equal to 15% of the thickness of the light-emitting chip 100. Through such an arrangement, a better excitation effect can be achieved, and hidden dangers such as line collapse caused by the glue point hitting the wire can also be avoided. In other words, in this embodiment, the horizontal height of the first fluorescent glue layer 200 in the solid crystal area is less than or equal to 125% of the thickness of the light-emitting chip 100, and more preferably less than or equal to 115% of the thickness of the light-emitting chip 100. Such a design can ensure that the second fluorescent glue layer 300 has sufficient operating space in most miniaturized bracket bowls on the market, which helps to achieve the purpose of the present invention.
[0022] Further, the ultra-narrow wave phosphor can be, for example, evenly distributed in the first fluorescent glue layer 200. By evenly distributing the ultra-narrow wave phosphor in the first fluorescent glue layer 200, a better excitation effect can be achieved. The second fluorescent glue layer 300 can, for example, have a layered structure. The second fluorescent glue layer 300 can, for example, include a precipitation layer 310 close to the first fluorescent layer 200 and a clear glue layer 320 arranged on the precipitation layer 310 away from the first fluorescent glue layer 200, that is, the clear glue layer 320 is located on the side of the precipitation layer 310 away from the light-emitting chip 100. In addition, the thickness of the clear glue layer 320 is less than the thickness of the precipitation layer 310. In other words, the light-emitting device of the present invention will have a longitudinal section, and the fluorescent glue can, for example, be displayed as a three-layer structure, including the first fluorescent glue layer 200, the precipitation layer 310 and the clear glue layer 320, the precipitation layer 310 is located between the first fluorescent glue layer 200 and the clear glue layer 320, and the clear glue layer 320 is located on the side of the precipitation layer 310 away from the light-emitting chip 100. The thickness of the second fluorescent glue layer 300 is greater than that of the first fluorescent glue layer 200; the thickness of the precipitation layer 310 is greater than that of the first fluorescent glue layer 200, and the thickness of the precipitation layer 310 is greater than that of the clear glue layer 320. It should be noted that the clear glue layer 320 does not completely contain fluorescent glue, but the content / concentration of fluorescent powder visible to the naked eye in the clear glue layer is less than that in the precipitation layer.
[0023] For example, when preparing the first fluorescent glue layer 200, it can be centrifuged at a low speed for a short time, for example, by semi-centrifugation. In this way, the surface of the fluorescent glue can be roughly leveled, but the ultra-narrow wave phosphor will not settle to the bottom, so that the ultra-narrow wave phosphor is evenly distributed in the first fluorescent glue layer 200. When preparing the second fluorescent glue layer 300, for example, a full centrifugation method can be used for long-term high-speed centrifugation. After full centrifugation, the lower layer of the second fluorescent glue layer 300 is precipitated to form a precipitation layer 310, and the upper layer forms a clear glue layer 320, so that the fluorescent glue can be better leveled and cover the lower first fluorescent glue layer 200. Leveling can improve the stability of subsequent operations, improve the concentration of color points, and improve the color uniformity at different angles. As a result, the flatness of the interface between the second fluorescent glue layer 300 and the first fluorescent glue layer 200 is greater than the flatness of the interface between the precipitation layer 310 and the clear glue layer 320. According to Figure 1 and Figure 2 It can be seen that the light-emitting device of the present invention has a longitudinal cross-section showing that the curvature of the boundary line between the second fluorescent glue layer 300 and the first fluorescent glue layer 200 (or the boundary line between the precipitation layer 310 and the first fluorescent glue layer 200) is greater than the curvature of the boundary line between the precipitation layer 310 and the clear glue layer 320, that is, the boundary line between the precipitation layer 310 and the clear glue layer 320 is smoother than the boundary line between the second fluorescent glue layer 300 and the first fluorescent glue layer 100. The above-mentioned operation mode of the first fluorescent glue layer 200 and the second fluorescent glue layer 300 is conducive to more stable mass production of light-emitting devices 100 with high color purity and brightness, and the production can have a higher yield, and the color tolerance of the mass-produced light-emitting devices 100 has a small change.
[0024] In this embodiment, the weight ratio of the ultra-narrow wave phosphor to the first phosphor glue layer 300 is in the range of 30% to 70%, and the weight ratio of the medium-wide wave phosphor to the second phosphor glue layer 300 is in the range of 35% to 75%. The weight ratio can be adjusted according to the specific selection of the light-emitting chip 100, the ultra-narrow wave phosphor and the medium-wide wave phosphor. When the light-emitting spectrum of the light-emitting device 10 after adjustment has the following characteristics, the purpose of the invention can be achieved. Figure 3 , Figure 3The luminous spectrum of the light-emitting device 10 provided in this embodiment. The normalized intensity value of the luminous spectrum below 580 nanometers is less than or equal to 6%; preferably, this intensity value may be less than or equal to 4%; more preferably, it may be less than or equal to 2%. By adjusting the specific collocation of the light-emitting chip 100 and the phosphor according to the specific requirements of the luminous spectrum of the light-emitting device 10, it can be ensured that the blue light emitted by the light-emitting chip 100 is fully absorbed by the first fluorescent glue layer 200 and the second fluorescent glue layer 300, thereby avoiding affecting the purity of the red light emitted by the light-emitting device 10. Simply put, in some embodiments, the color coordinates of the light emitted by the light-emitting chip 100 that excites the first fluorescent glue layer 200 and the second fluorescent glue layer 300 are located at (x, y), where x>0.6850, y<0.3050, which meets the basic requirements of high color purity red light.
[0025] Further, the luminous spectrum of the light-emitting device 10 may, for example, have a first peak inflection point Wp1 and a second peak inflection point Wp2, wherein the wavelength range of the first peak inflection point Wp1 is 630±2 nanometers, and the wavelength range of the second peak inflection point Wp2 is 645-700 nanometers. In most embodiments, the second peak inflection point Wp2 is usually the peak value of the light-emitting device 100. In a preferred embodiment, the intensity of the first peak inflection point Wp1 is less than the intensity of the second peak inflection point Wp2, so as to ensure that the ultra-narrow wave phosphor with a shorter wavelength is not excessively used, and the color coordinates (x, y) of the light-emitting device 100 will not deviate from the basic requirements of x>0.6850, y<0.3050 and affect the red light purity. The normalization process is performed with the intensity of the second peak inflection point Wp2 as 100%. The normalized intensity of the first peak inflection point Wp1 is less than 95%, preferably 75%-95%, which can achieve a better balance between color purity and brightness. In other words, the intensity of the first emission wavelength of the light emitting device 100 of this embodiment is smaller than the intensity of the second emission wavelength.
[0026] In some embodiments, the light spectrum of the light emitting device 10 may, for example, further include a third peak inflection point Wp3 between the first peak inflection point Wp1 and the second peak inflection point Wp2, and the wavelength range of the third peak inflection point Wp3 is 635±2 nanometers; in other embodiments, the light spectrum of the light emitting device 10 may, for example, further include a fourth peak inflection point Wp4 between the first peak inflection point Wp1 and the second peak inflection point Wp2, and the wavelength range of the fourth peak inflection point Wp4 is 645±2 nanometers. The normalized intensity of the third peak inflection point Wp3 may be 75% to 95%, and the normalized intensity of the fourth peak inflection point Wp4 may be 80% to 95%.
[0027] In summary, the light-emitting device 10 of the present invention, through the arrangement of the first fluorescent glue layer 200 and the second fluorescent glue layer 200, and through the coordinated use of the light-emitting chip 100, the ultra-narrow wave phosphor, and the medium-wide wave phosphor, influences each other, so that at least one of the first fluorescent glue layer and the second fluorescent glue layer has a first emission wavelength in the range of 630±2 nanometers (manifested as a first peak inflection point Wp1 in the light-emitting spectrum), and at least one of the first fluorescent glue layer and the second fluorescent glue layer has a second emission wavelength in the range of 650-690 nanometers (manifested as a second peak inflection point Wp2 in the light-emitting spectrum), so that the light color purity of the light emitted by the light-emitting device 10 reaches more than 99% and has a high brightness.
[0028] In addition, it can be understood that the aforementioned embodiments are only exemplary descriptions of the present invention. Under the premise that the technical features do not conflict, the structures do not contradict, and the purpose of the present invention is not violated, the technical solutions of the various embodiments can be arbitrarily combined and used in combination.
[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions 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: include: Light-emitting chip; A first fluorescent adhesive layer, surrounding the light-emitting chip; as well as A second fluorescent adhesive layer, disposed on the first fluorescent adhesive layer and covering the light-emitting chip; At least one of the first fluorescent glue layer and the second fluorescent glue layer has a first emission wavelength in the range of 630±2 nanometers, and at least one of the first fluorescent glue layer and the second fluorescent glue layer has a second emission wavelength in the range of 650-690 nanometers.
2. The light emitting device according to claim 1, characterized in that: The intensity of the first emission wavelength is less than the intensity of the second emission wavelength.
3. The light emitting device according to claim 1, characterized in that: The first fluorescent glue layer does not cover the upper surface of the light-emitting chip.
4. The light emitting device according to claim 1, characterized in that: The first fluorescent glue layer is arranged around the light-emitting chip and covers the upper surface of the light-emitting chip. The thickness of the first fluorescent glue layer covering the upper surface of the light-emitting chip is less than or equal to 25% of the thickness of the light-emitting chip.
5. The light emitting device according to claim 1, characterized in that: The second fluorescent glue layer has a layered structure, and includes a precipitation layer close to the first fluorescent layer and a clear glue layer located on the precipitation layer and away from the first fluorescent glue layer.
6. The light emitting device according to claim 5, characterized in that: The thickness of the clear glue layer is smaller than the thickness of the precipitation layer, and the thickness of the first fluorescent glue layer is smaller than the thickness of the precipitation layer.
7. The light emitting device according to claim 1, characterized in that: The light emitting device has a light emitting spectrum, and the normalized intensity of the light emitting spectrum below 580 nanometers is less than or equal to 6%.
8. The light emitting device according to any one of claims 1 to 7, characterized in that: The light emitting spectrum of the light emitting device has a first peak inflection point and a second peak inflection point, the wavelength range of the first peak inflection point is 630±2 nanometers, the wavelength range of the second peak inflection point is 650-690 nanometers, and the intensity ratio of the first peak inflection point to the second peak inflection point is less than 95%.
9. The light emitting device according to claim 8, characterized in that: The light-emitting spectrum of the light-emitting device also includes a third peak inflection point and a fourth peak inflection point, the wavelength value of the third peak inflection point is 635±2 nanometers, and the wavelength value of the fourth peak inflection point is 645±2 nanometers; the normalized intensity range of the third peak inflection point is 75% to 95%, and the normalized intensity range of the fourth peak inflection point is 80% to 95%.
10. The light emitting device according to claim 1, characterized in that: The color coordinates of the light emitted by the light emitting device fall at (x, y), wherein x>0.6850 and y<0.3050.