Light emitting unit and method of manufacturing the same

Abstract

The present disclosure provides a light emitting unit and a manufacturing method thereof. The light emitting unit comprises a light emitting diode chip, a fluorescent sheet and a light blocking layer. The light blocking layer surrounds the light emitting diode chip, and the light blocking layer has a first recess. The fluorescent sheet is located on a light emitting surface of the light emitting diode chip, and the fluorescent sheet is located in the first recess. The fluorescent sheet comprises a transparent protective layer and a fluorescent powder layer. The transparent protective layer has a second recess, and the fluorescent powder layer is located in the second recess. A sidewall of the second recess is located between the fluorescent powder layer and a sidewall of the first recess. The fluorescent powder layer is located between the light emitting diode chip and a bottom surface of the first recess.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to a light-emitting unit and a method for manufacturing the same. Background Technology

[0002] Light-emitting diode (LED) chips can be packaged into light-emitting units. Light-emitting units packaged with LED chips have advantages such as energy saving, high brightness, high durability, long life and light weight, and have been widely used in lighting and display fields.

[0003] The related technology provides a light-emitting unit, which includes a circuit board, a light-emitting diode chip, and a phosphor. The light-emitting diode chip is located on the circuit board and electrically connected to the circuit board, and the phosphor is located on the light-emitting diode chip and is in contact with the light-emitting surface of the light-emitting diode chip.

[0004] However, the aforementioned light-emitting units provided by related technologies require the phosphor sheet to be manufactured separately. The phosphor sheet needs to be patterned during the manufacturing process. Cooling water or water mist is required to cool the phosphor sheet during patterning. Moisture can seep into the phosphor sheet, causing the phosphor to hydrolyze and reducing the brightness of the light-emitting unit. Even if a dry-cutting process is used for patterning, dust contamination and edge chipping of the phosphor sheet are likely to occur during cutting, resulting in exposed phosphor sheet surfaces. In subsequent use, moisture can easily penetrate, leading to poor long-term reliability. Summary of the Invention

[0005] This disclosure provides a light-emitting unit and its manufacturing method, which can improve the brightness and reliability of the light-emitting unit. The technical solution is as follows: On the one hand, a light-emitting unit is provided, the light-emitting unit comprising: a light-emitting diode chip, a phosphor sheet, and a light-blocking layer; The light-blocking layer surrounds the light-emitting diode chip, the light-blocking layer has a first groove, the phosphor is located on the light-emitting surface of the light-emitting diode chip, and the phosphor is located in the first groove; The phosphor sheet includes a transparent protective layer and a phosphor layer. The transparent protective layer has a second groove. The phosphor layer is located in the second groove. The sidewall of the second groove is located between the phosphor layer and the sidewall of the first groove. The phosphor layer is located between the light-emitting diode chip and the bottom surface of the first groove.

[0006] Optionally, the transparent protective layer is a transparent silicone layer. Optionally, the orthographic projection of the light-emitting diode chip onto the light-emitting surface is located inside the orthographic projection of the second groove onto the light-emitting surface; The second groove is projected onto the light-emitting surface in a projection that is inside the first groove projected onto the light-emitting surface.

[0007] Optionally, the thickness of the fluorescent sheet is equal to the depth of the first groove.

[0008] On the other hand, a method for manufacturing a light-emitting unit is provided, the method comprising: A fluorescent sheet is fabricated, the fluorescent sheet comprising a transparent protective layer and a phosphor layer, the transparent protective layer having a second groove, and the phosphor layer being located within the second groove; The phosphor sheet is bonded to the light-emitting diode chip, with the phosphor sheet located on the light-emitting surface of the light-emitting diode chip, and the phosphor layer in contact with the light-emitting diode chip; A light-blocking layer is formed around the light-emitting diode chip. The light-blocking layer has a first groove, and the phosphor is located in the first groove. The sidewall of the second groove is located between the phosphor layer and the sidewall of the first groove. The phosphor layer is located between the bottom surface of the light-emitting diode chip and the first groove.

[0009] Optionally, the fabrication of the fluorescent sheet includes: The transparent silicone is filled into the first mold cavity; The first mold is subjected to molding and heating to solidify the transparent silicone to form the transparent protective layer, the transparent protective layer including the second groove; Remove the first mold; The phosphor is mixed with organosilicon gel, and after vacuum degassing, it is injected into the second groove to form the phosphor layer.

[0010] Optionally, the fabrication of the fluorescent sheet further includes: The phosphor layer is first baked at a first temperature; The phosphor layer is baked a second time at a second temperature, wherein the first temperature is lower than the second temperature; The phosphor layer is baked a third time at a third temperature, where the second temperature is lower than the third temperature.

[0011] Optionally, the first temperature is 70~90℃, the second temperature is 110~130℃, and the third temperature is 140~160℃; The first baking time is 20-40 minutes, the second baking time is 50-70 minutes, and the third baking time is 20-40 minutes.

[0012] Optionally, bonding the phosphor sheet to the light-emitting diode chip includes: A transparent silicone adhesive is uniformly coated on the light-emitting surface of the light-emitting diode chip; The fluorescent sheet is precisely aligned and bonded, and then hot-pressed using a vacuum hot-pressing process. The transparent silicone adhesive is cured by heating, so that the light-emitting diode chip and the phosphor are bonded together.

[0013] Optionally, a light-blocking layer is formed around the light-emitting diode chip, including: The light-emitting diode chip with the fluorescent sheet attached is placed into the second mold cavity, and nano-titanium dioxide white glue is coated around the light-emitting diode chip and the fluorescent sheet to form the light-blocking layer; The second mold is heated to solidify the light-blocking layer; Remove the second mold.

[0014] The beneficial effects of the technical solutions provided in this disclosure are: In this embodiment, a light-blocking layer surrounds the LED chip to prevent light leakage from the side of the LED. The light-blocking layer has a first groove, within which a phosphor sheet is located. The first groove of the light-blocking layer can fix the phosphor sheet and seal its sidewalls, preventing moisture from the external environment from entering the phosphor sheet. Simultaneously, the phosphor sheet includes a transparent protective layer and a phosphor layer. The transparent protective layer has a second groove, within which the phosphor layer is located. The sidewall of the second groove surrounds the phosphor layer, preventing the phosphor sheet's cross-section from being exposed. The sidewall of the second groove is located between the phosphor layer and the sidewall of the first groove, and the phosphor layer is located between the LED chip and the bottom surface of the first groove. This design allows the second and first grooves to completely seal the phosphor sheet and the LED chip, thereby further enhancing the airtightness of the light-emitting unit and improving the long-term reliability of the product. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this disclosure, 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 this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a cross-sectional view of a light-emitting unit provided in an embodiment of this disclosure; Figure 2 This is a flowchart of the method for fabricating a light-emitting unit provided in the embodiments of this disclosure; Figure 3 This is a flowchart of a method for fabricating a light-emitting unit according to an embodiment of the present disclosure; Figure 4 This is a structural diagram illustrating the fabrication process of a light-emitting unit according to an embodiment of this disclosure; Figure 5This is a structural diagram illustrating the fabrication process of a light-emitting unit according to an embodiment of this disclosure; Figure 6 This is a structural diagram illustrating the fabrication process of a light-emitting unit according to an embodiment of this disclosure; Figure 7 This is a structural diagram of the manufacturing process of a light-emitting unit provided in an embodiment of this disclosure.

[0017] The attached figures are labeled as follows: 101: Circuit board; 102: Light-emitting diode chip; 103: Phosphor sheet; 104: Light-blocking layer; 1031: Transparent protective layer; 1032: Phosphor layer; 1001: First groove; 1002: Second groove; 2001: Second mold cavity; a: Length of the fluorescent sheet; b: Depth of the second groove; c: Thickness of the fluorescent sheet; d: Thickness of the sidewall of the second groove. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0019] Figure 1 This is a cross-sectional view of a light-emitting unit provided in an embodiment of this disclosure. See also... Figure 1 The light-emitting unit includes: a light-emitting diode chip 102, a phosphor sheet 103, and a light-blocking layer 104.

[0020] A light-blocking layer 104 surrounds a light-emitting diode chip 102. The light-blocking layer 104 has a first groove 1001. A phosphor sheet 103 is located on the light-emitting surface of the light-emitting diode chip 102 and is located within the first groove 1001.

[0021] The phosphor sheet 103 includes a transparent protective layer 1031 and a phosphor layer 1032. The transparent protective layer 1031 has a second groove 1002. The phosphor layer 1032 is located in the second groove 1002. The sidewall of the second groove 1002 is located between the phosphor layer 1032 and the sidewall of the first groove 1001. The phosphor layer 1032 is located between the light-emitting diode chip 102 and the bottom surface of the first groove 1001.

[0022] In this embodiment, a light-blocking layer surrounds the LED chip to prevent light leakage from the side of the LED. The light-blocking layer has a first groove, within which a phosphor sheet is located. The first groove of the light-blocking layer can fix the phosphor sheet and seal its sidewalls, preventing moisture from the external environment from entering the phosphor sheet. Simultaneously, the phosphor sheet includes a transparent protective layer and a phosphor layer. The transparent protective layer has a second groove, within which the phosphor layer is located. The sidewall of the second groove surrounds the phosphor layer, preventing the phosphor sheet's cross-section from being exposed. The sidewall of the second groove is located between the phosphor layer and the sidewall of the first groove, and the phosphor layer is located between the LED chip and the bottom surface of the first groove. This design allows the second and first grooves to completely seal the phosphor sheet and the LED chip, thereby further enhancing the airtightness of the light-emitting unit and improving the long-term reliability of the product.

[0023] In this embodiment of the disclosure, the light-emitting unit can be an LED chip.

[0024] In this embodiment of the disclosure, the light-emitting diode chip 102 can be a flip-chip light-emitting diode chip.

[0025] In this embodiment of the disclosure, the projection of the light-emitting diode chip 102 onto the light-emitting surface can be rectangular or circular.

[0026] In other embodiments, the projection of the light-emitting diode chip 102 onto the light-emitting surface can also be other shapes, such as ellipse.

[0027] In this embodiment of the disclosure, the orthographic projection of the light-emitting diode chip 102 on the light-emitting surface is located inside the orthographic projection of the second groove 1002 on the light-emitting surface.

[0028] The orthographic projection of the second groove 1002 onto the light-emitting surface is located inside the orthographic projection of the first groove 1001 onto the light-emitting surface.

[0029] In this implementation, the orthographic projection of the LED chip on the light-emitting surface is located inside the orthographic projection of the second groove on the light-emitting surface. This ensures that the phosphor completely covers the light-emitting surface of the LED chip and avoids the light-blocking layer fabrication being affected by misalignment between the phosphor and the LED chip. The orthographic projection of the second groove on the light-emitting surface is located inside the orthographic projection of the first groove on the light-emitting surface, which allows the phosphor layer to completely cover the surface of the LED chip. At the same time, the sidewall of the second groove fills the first groove, sealing the phosphor and thus improving the yield of the light-emitting unit.

[0030] In this embodiment of the disclosure, the sidewall thickness of the second groove 1002 is less than the sidewall thickness of the first groove 1001.

[0031] In this implementation, the sidewall thickness of the second groove is less than that of the first groove. The light-blocking layer, as the outer enclosure structure, has a thicker sidewall, which can effectively prevent external moisture, dust, and corrosive gases from seeping into the cavity through the side gaps. Meanwhile, the reduced sidewall thickness of the inner fluorescent sheet can reduce the gap at the connection between the fluorescent sheet and the light-blocking layer, avoiding the problem of poor adhesion caused by excessively thick sidewalls.

[0032] In this embodiment of the disclosure, the sidewall thickness d of the second groove 1002 is 10~15μm.

[0033] In this implementation, the sidewall thickness of the second groove 1002 is 10~15μm. The width is neither too wide, which would cause the light-blocking layer to be too thin and reduce its light-blocking ability, nor too thin, which would result in insufficient blocking ability against water vapor.

[0034] For example, the sidewall thickness d of the second groove 1002 is 13 μm.

[0035] In this embodiment of the disclosure, the projection of the fluorescent sheet 103 onto the light-emitting surface can be rectangular or circular.

[0036] In other embodiments, the projection of the fluorescent sheet 103 onto the light-emitting surface can also be other shapes, such as ellipse.

[0037] In this embodiment of the present disclosure, the length 'a' of the cross section of the phosphor sheet 103 perpendicular to the light-emitting surface is 2-5 μm longer than the length of the cross section of the light-emitting diode chip 102 perpendicular to the light-emitting surface.

[0038] In this implementation, the length of the cross-section of the phosphor sheet perpendicular to the light-emitting surface is 2~5μm longer than the length of the cross-section of the LED chip perpendicular to the light-emitting surface. This ensures that the phosphor sheet completely covers the light-emitting surface of the LED chip, while avoiding the situation where the size of the phosphor sheet is too large, resulting in an excessively large light-emitting unit.

[0039] Taking the circular fluorescent sheet 103 as an example, the length a is also the diameter of the circular fluorescent sheet 103.

[0040] For example, the length 'a' of the phosphor sheet 103 is 3 μm longer than the length of the light-emitting diode chip 102.

[0041] In this embodiment of the disclosure, the thickness c of the fluorescent sheet 103 is 70~90μm, and the depth b of the second groove 1002 is 30~50μm.

[0042] For example, the thickness c of the fluorescent sheet 103 is 80 μm, and the depth b of the second groove 1002 is 40 μm.

[0043] In this embodiment of the disclosure, the projection shape of the first groove and the second groove on the light-emitting surface can be circular, and the projections of the first groove and the second groove are arranged concentrically.

[0044] In this embodiment of the disclosure, the transparent protective layer 1031 is a transparent silicone layer.

[0045] In this implementation, the transparent silicone layer can ensure the light transmittance of the phosphor sheet and also has good ductility when making the phosphor sheet, which can completely fill the gap of the second groove and improve the sealing of the light-emitting unit. At the same time, the transparent silicone layer can also provide protection for the phosphor layer.

[0046] In this embodiment, the thickness of the phosphor layer 1032 is 30~50μm.

[0047] For example, the thickness of the phosphor layer 1032 is 40 μm.

[0048] In this embodiment, the phosphor layer 1032 can be a mixture of high color gamut fluoride phosphor, nitride green phosphor, aluminate yellow phosphor, and organosilicon gel.

[0049] In the embodiments disclosed herein, the high color gamut fluoride phosphor may be one or a combination of two of potassium hexafluorosilicate manganese doped (KSF) and potassium hexafluorogermanate manganese phosphor (KGF).

[0050] In this embodiment, the high color gamut phosphor has a mass fraction of 15-45.

[0051] For example, the mass fraction of the high color gamut phosphor is 27.

[0052] In this embodiment, the mass fraction of the nitride green powder is 5-20.

[0053] For example, the mass fraction of the nitride green powder is 11.

[0054] In this embodiment, the mass fraction of aluminate yellow powder is 0-10.

[0055] For example, the mass fraction of aluminate yellow powder is 1.

[0056] In the embodiments of this disclosure, the mass fraction of the mixture of organosilicon gels is 40-80.

[0057] For example, the mixture of silicone gels has a mass fraction of 61.

[0058] In this embodiment, the light-blocking layer 104 is a nano-titanium dioxide white adhesive layer.

[0059] In this embodiment of the disclosure, the projection of the light-blocking layer 104 onto the light-emitting surface can be rectangular or circular.

[0060] In other embodiments, the projection of the light-blocking layer 104 onto the light-emitting surface can also be other shapes, such as ellipse.

[0061] In this embodiment of the disclosure, the light-blocking layer 104 may be a mixture of nano-titanium dioxide and silicone.

[0062] In the embodiments of this disclosure, the proportion of nano-titanium dioxide in the mixture of nano-titanium dioxide and organosilicon is 50-70%.

[0063] For example, the proportion of nano-titanium dioxide is 60%.

[0064] In this embodiment, the nano-titanium dioxide particle size is 30 nm.

[0065] In this embodiment of the disclosure, the height of the light-blocking layer 104 in the direction perpendicular to the light-emitting surface is 20~25μm.

[0066] For example, the height of the light-blocking layer 104 in the direction perpendicular to the light-emitting surface is 22 μm. In this embodiment of the disclosure, the light transmittance of the light-blocking layer 104 is less than 0.5%.

[0067] For example, the light-blocking layer 104 has a light transmittance of 0.4%.

[0068] In this embodiment of the disclosure, the light-emitting unit may further include: a circuit board 101, the circuit board 101 including electrodes located on the surface of the circuit board 101, and a light-emitting diode chip 102 located on the circuit board 101 and electrically connected to the electrodes of the circuit board 101.

[0069] Figure 2 This is a flowchart of a method for fabricating a light-emitting unit according to an embodiment of this disclosure. See also... Figure 2 The method includes the following steps: S11. Fabricate a fluorescent sheet, the fluorescent sheet comprising a transparent protective layer and a phosphor layer, the transparent protective layer having a second groove, the phosphor layer being located within the second groove.

[0070] S12. The phosphor sheet is bonded to the light-emitting diode chip, with the phosphor sheet located on the light-emitting surface of the light-emitting diode chip and the phosphor layer in contact with the light-emitting diode chip.

[0071] S13. A light-blocking layer is formed around the light-emitting diode chip. The light-blocking layer surrounds the light-emitting diode chip. The light-blocking layer has a first groove, and the phosphor is located in the first groove. The sidewall of the second groove is located between the phosphor layer and the sidewall of the first groove. The phosphor layer is located between the light-emitting diode chip and the bottom surface of the first groove.

[0072] In this embodiment, a light-blocking layer surrounds the LED chip to prevent light leakage from the side of the LED. The light-blocking layer has a first groove, within which a phosphor sheet is located. The first groove of the light-blocking layer can fix the phosphor sheet and seal its sidewalls, preventing moisture from the external environment from entering the phosphor sheet. Simultaneously, the phosphor sheet includes a transparent protective layer and a phosphor layer. The transparent protective layer has a second groove, within which the phosphor layer is located. The sidewall of the second groove surrounds the phosphor layer, preventing the phosphor sheet's cross-section from being exposed. The sidewall of the second groove is located between the phosphor layer and the sidewall of the first groove, and the phosphor layer is located between the LED chip and the bottom surface of the first groove. This design allows the second and first grooves to completely seal the phosphor sheet and the LED chip, thereby further enhancing the airtightness of the light-emitting unit and improving the long-term reliability of the product.

[0073] Figure 3 This is a flowchart illustrating a method for fabricating a light-emitting unit according to an embodiment of this disclosure. See also... Figure 3 The method includes the following steps: S21. Fabricate a fluorescent sheet, which includes a transparent protective layer and a phosphor layer. The transparent protective layer has a second groove, and the phosphor layer is located in the second groove.

[0074] For example, step S21 may include: The first step is to fill the first mold cavity with transparent silicone.

[0075] The second step involves molding and heating the first mold to solidify the transparent silicone to form the transparent protective layer, which includes the second groove.

[0076] In this embodiment of the disclosure, transparent silicone with a first mold is initially cured and molded at 80~120°C for 3~5 minutes by molding and heating to form a transparent protective layer.

[0077] For example, transparent silicone with a first mold is initially cured at 100°C for 4 minutes by molding and heating to form a transparent protective layer.

[0078] The third step is to remove the first mold.

[0079] Figure 4This is a structural diagram illustrating the fabrication process of a light-emitting unit according to an embodiment of this disclosure. See also... Figure 4 The transparent protective layer 1031 has a second groove 1002.

[0080] The fourth step involves mixing the phosphor with the organosilicon gel, degassing it under vacuum, and then injecting the mixture into the second groove to form the phosphor layer.

[0081] In the embodiments disclosed herein, the phosphor may include high gamut fluoride phosphor, nitride green phosphor, and aluminate yellow phosphor.

[0082] In the embodiments disclosed herein, the high color gamut fluoride phosphor can be one or a combination of KSF phosphor and KGF phosphor.

[0083] In this embodiment, the high color gamut phosphor has a mass fraction of 15-45.

[0084] For example, the mass fraction of the high color gamut phosphor is 27.

[0085] In this embodiment, the mass fraction of the nitride green powder is 5-20.

[0086] For example, the mass fraction of the nitride green powder is 11.

[0087] In this embodiment, the mass fraction of aluminate yellow powder is 0-10.

[0088] For example, the mass fraction of aluminate yellow powder is 1.

[0089] In the embodiments of this disclosure, the mass fraction of the mixture of organosilicon gels is 40-80.

[0090] For example, the mixture of silicone gels has a mass fraction of 61.

[0091] In this embodiment of the disclosure, the thickness of the phosphor layer is 30~50μm.

[0092] For example, the thickness of the phosphor layer is 40 μm.

[0093] The fifth step is to bake the phosphor layer for the first time at the first temperature.

[0094] The sixth step is to bake the phosphor layer a second time at a second temperature, where the first temperature is lower than the second temperature.

[0095] Step 7: The phosphor layer is baked for the third time at a third temperature, where the second temperature is lower than the third temperature.

[0096] In this implementation, the first temperature is lower than the second temperature, and the second temperature is lower than the third temperature. The low first temperature allows the solvent, diluent, and trace amounts of water vapor inside the phosphor layer to evaporate slowly, preventing air bubbles from forming inside the adhesive layer and ensuring sufficient air release inside the phosphor layer. After rising to the second temperature, the phosphor layer can be uniformly bonded and shaped, avoiding edge cracking caused by rapid high-temperature curing and improving the overall flatness of the phosphor layer. Finally, curing is completed at the highest third temperature, improving the density of the phosphor layer.

[0097] Figure 5 This is a structural diagram illustrating the fabrication process of a light-emitting unit according to an embodiment of this disclosure. See also... Figure 5 The fluorescent sheet 103 includes a transparent protective layer 1031 and a phosphor layer 1032, with the phosphor layer 1032 located within the second groove 1002.

[0098] In this embodiment of the disclosure, the first temperature is 70~90℃, the second temperature is 110~130℃, the third temperature is 140~160℃, the first baking time is 20~40 minutes, the second baking time is 50~70 minutes, and the third baking time is 20~40 minutes.

[0099] In this implementation, the first temperature is 70~90℃, and the first baking time is 20~40 minutes. This low temperature combined with a moderate baking time prevents the transparent protective layer from rapidly cross-linking and curing, allowing the phosphor layer to initially soften and set, providing a stable basic structure for subsequent curing. The second temperature is 110~130℃, and the second baking time is 50~70 minutes. This is the longest baking time, and the long constant temperature allows the cross-linking reaction to proceed gradually and fully, gradually releasing the internal stress generated by the curing shrinkage of the colloid and improving the density of the phosphor sheet. The third temperature is 140~160℃, and the third baking time is 20~40 minutes. This temperature range is the temperature range for complete curing of the transparent protective layer. Based on the first two stages of gradient heating and pre-baking and pre-curing, the high temperature can quickly form a high-density stable structure of the colloid, significantly improving the density of the phosphor layer.

[0100] For example, the first temperature is 80°C, the second temperature is 120°C, the third temperature is 150°C, the first baking time is 30 minutes, the second baking time is 60 minutes, and the third baking time is 30 minutes.

[0101] In this embodiment, the thickness of the fluorescent sheet is 70-90 μm, and the depth of the second groove is 30-50 μm.

[0102] For example, the thickness of the fluorescent sheet is 80 μm and the depth of the second groove is 40 μm.

[0103] In this embodiment of the disclosure, the projection shape of the first groove and the second groove on the light-emitting surface can be circular, and the projections of the first groove and the second groove are arranged concentrically.

[0104] S22. Preprocess the LED chip.

[0105] In this embodiment of the disclosure, the light-emitting diode chip can be a flip-chip light-emitting diode chip.

[0106] In this embodiment of the disclosure, the projection of the light-emitting diode chip onto the light-emitting surface can be rectangular or circular.

[0107] In other embodiments, the projection of the light-emitting diode chip onto the light-emitting surface can also be other shapes, such as ellipse.

[0108] For example, step S22 may include: The first step is to take the LED chips arranged in an array on an ultraviolet (UV) film, with the light-emitting side of the LED chips facing upwards.

[0109] The second step is to perform plasma cleaning on the light-emitting surface of the LED chip.

[0110] In this implementation, plasma cleaning of the light-emitting surface of the LED chip can remove surface oil and impurities, thereby improving the adhesion of the subsequent film.

[0111] S23. Bond the fluorescent sheet to the light-emitting diode chip.

[0112] For example, step S23 may include: The first step is to uniformly coat the light-emitting surface of the LED chip with transparent silicone adhesive.

[0113] The second step is to precisely align and bond the fluorescent sheet, and then perform hot pressing using a vacuum hot pressing process.

[0114] In this implementation, vacuum hot pressing can quickly remove microbubbles from the silicone adhesive, enabling the phosphor sheet to be bonded parallel to the light-emitting diode chip, thus improving the compactness of the light-emitting device.

[0115] In this embodiment of the disclosure, vacuum hot pressing is performed at a temperature of 60~80℃ and a pressure of 0.1~0.3MPa for 10~20s.

[0116] For example, vacuum hot pressing is performed at a temperature of 70°C and a pressure of 0.2 MPa for 15 seconds. The third step is to heat and cure the transparent silicone adhesive, so that the light-emitting diode chip and the phosphor sheet are bonded together.

[0117] In this embodiment of the present disclosure, the product is cured at a temperature of 50–60°C for 20–30 minutes.

[0118] In this implementation, curing at a temperature of 50–60°C for 20–30 minutes can further cure the silicone adhesive under the above process conditions, making the phosphor sheet and the light-emitting diode chip tightly connected.

[0119] For example, it is cured at a temperature of 55°C for 25 minutes.

[0120] Figure 6 This is a structural diagram illustrating the fabrication process of a light-emitting unit according to an embodiment of this disclosure. See also... Figure 6 The fluorescent sheet 103 is bonded to the light-emitting diode chip 102.

[0121] In this embodiment of the disclosure, the projection of the fluorescent sheet onto the light-emitting surface can be rectangular or circular.

[0122] In other embodiments, the projection of the phosphor sheet onto the light-emitting surface can also be other shapes, such as an ellipse.

[0123] In this embodiment of the disclosure, the length of the cross-section of the phosphor sheet perpendicular to the light-emitting surface is 2 to 5 μm longer than the length of the cross-section of the light-emitting diode chip perpendicular to the light-emitting surface.

[0124] In this implementation, the length of the cross-section of the phosphor sheet perpendicular to the light-emitting surface is 2~5μm longer than the length of the cross-section of the LED chip perpendicular to the light-emitting surface. This ensures that the phosphor sheet completely covers the light-emitting surface of the LED chip, while avoiding the situation where the size of the phosphor sheet is too large, resulting in an excessively large light-emitting unit.

[0125] Taking a circular fluorescent sheet as an example, this length is also the diameter of the circular fluorescent sheet.

[0126] For example, the length of the phosphor sheet is 3 μm longer than the length of the light-emitting diode chip.

[0127] S24. Create a light-blocking layer around the LED chip.

[0128] For example, step S24 may include: The first step is to place the light-emitting diode chip with the fluorescent sheet attached into the second mold cavity, and to coat the light-emitting diode chip and the fluorescent sheet with nano-titanium dioxide white glue to form the light-blocking layer.

[0129] In this embodiment, the first mold and the second mold can be the same mold or different molds. When using the same mold, the transparent protective layer and the light-blocking layer are located in different areas of the mold. When using different molds, the first mold is used to create the transparent protective layer, and the second mold is used to create the light-blocking layer.

[0130] The second step is to heat the second mold to solidify the light-blocking layer.

[0131] In this embodiment of the disclosure, the light-blocking layer is heated for 30 to 60 minutes at a temperature of 100 to 130°C.

[0132] In this implementation, heating the light-blocking layer at a temperature of 100~130℃ for 30~60 minutes can completely cure the light-blocking layer.

[0133] For example, the light-blocking layer is heated at a temperature of 115°C for 45 minutes.

[0134] Figure 7 This is a structural diagram illustrating the fabrication process of a light-emitting unit according to an embodiment of this disclosure. See also... Figure 7 A light-emitting diode chip 102, with a phosphor sheet 103 attached, is located within the second mold cavity 2001. A light-blocking layer 104 is formed around the light-emitting diode chip 102 and the phosphor sheet 103, and the light-blocking layer 104 has a first groove 1001. As shown in the figure, the same second mold can simultaneously fabricate light-blocking layers for multiple light-emitting units. Similarly, the aforementioned first mold can also simultaneously fabricate transparent protective layers for multiple light-emitting units.

[0135] The third step is to remove the second mold.

[0136] In this implementation, the light-emitting unit made using the above method does not require cutting phosphor sheets and light-blocking layers, and finally obtains a single high color gamut chip-scale package (CSP) lamp bead.

[0137] In this embodiment of the disclosure, the orthographic projection of the light-emitting diode chip on the light-emitting surface is located inside the orthographic projection of the second groove on the light-emitting surface.

[0138] The orthographic projection of the second groove onto the light-emitting surface is located inside the orthographic projection of the first groove onto the light-emitting surface.

[0139] In this implementation, the orthographic projection of the LED chip on the light-emitting surface is located inside the orthographic projection of the second groove on the light-emitting surface. This ensures that the phosphor completely covers the light-emitting surface of the LED chip and avoids the light-blocking layer fabrication being affected by misalignment between the phosphor and the LED chip. The orthographic projection of the second groove on the light-emitting surface is located inside the orthographic projection of the first groove on the light-emitting surface, which allows the phosphor layer to completely cover the surface of the LED chip. At the same time, the sidewall of the second groove fills the first groove, sealing the phosphor and thus improving the yield of the light-emitting unit.

[0140] In this embodiment of the disclosure, the sidewall thickness of the second groove is less than the sidewall thickness of the first groove.

[0141] In this implementation, the sidewall thickness of the second groove is less than that of the first groove. The light-blocking layer, as the outer enclosure structure, has a thicker sidewall, which can effectively prevent external moisture, dust, and corrosive gases from seeping into the cavity through the side gaps. Meanwhile, the reduced sidewall thickness of the inner fluorescent sheet can reduce the gap at the connection between the fluorescent sheet and the light-blocking layer, avoiding the problem of poor adhesion caused by excessively thick sidewalls.

[0142] In this embodiment of the disclosure, the sidewall thickness of the second groove is 10~15μm.

[0143] In this implementation, the sidewall thickness of the second groove is 10~15μm. The width is neither too wide, which would cause the light-blocking layer to be too thin and reduce its light-blocking ability, nor too wide, which would result in insufficient blocking ability against water vapor.

[0144] For example, the sidewall thickness of the second groove is 13 μm.

[0145] In this embodiment of the disclosure, the projection of the light-blocking layer onto the light-emitting surface can be rectangular or circular.

[0146] In other embodiments, the projection of the light-blocking layer onto the light-emitting surface can also be other shapes, such as an ellipse.

[0147] In this embodiment of the disclosure, the light-blocking layer may be a mixture of nano-titanium dioxide and silicone.

[0148] In this embodiment of the disclosure, the height of the light-blocking layer in the direction perpendicular to the cross-section of the light-emitting surface is 20~25μm.

[0149] For example, the height of the light-blocking layer in the direction perpendicular to the cross-section of the light-emitting surface is 22 μm. In the embodiments of this disclosure, the proportion of nano-titanium dioxide in the mixture of nano-titanium dioxide and organosilicon is 50-70%.

[0150] For example, the proportion of nano-titanium dioxide is 60%.

[0151] In this embodiment, the nano-titanium dioxide particle size is 30 nm.

[0152] In this embodiment of the disclosure, the light transmittance of the light-blocking layer is less than 0.5%.

[0153] In this implementation, the light-blocking layer can effectively reflect the light emitted from the side of the LED chip to the front of the LED chip, thus avoiding the problems of light leakage and crosstalk from the side of the LED chip.

[0154] For example, the light-blocking layer has a light transmittance of 0.4%.

[0155] Table 1 below compares the test items of the light-emitting device provided in the embodiments of this disclosure with those provided in related technologies. As can be seen from Table 1, the light-emitting device provided in the embodiments of this disclosure has a lower phosphor hydrolysis rate, higher color gamut coverage, lower 1000h aging light decay rate, and no significant crosstalk in the light-emitting unit.

[0156] The light-emitting device manufactured using the embodiments of this disclosure employs a pre-fabricated phosphor sheet process, eliminating the traditional phosphor adhesive layer cutting process. This fundamentally avoids contact between cutting moisture and phosphor, solving the hydrolysis problem of fluoride phosphors and reducing the LED chip hydrolysis rate to 0%. A nano-titanium dioxide white adhesive light-blocking layer is set around the LED chip to achieve full-circumferential light blocking, effectively blocking light crosstalk between adjacent LED chips, improving light purity and color gamut coverage, and ensuring a high color gamut display effect. The mold precisely controls the size of the phosphor sheet and the light-blocking layer. The size of the phosphor sheet is 2-5 μm larger than the LED chip, ensuring that the phosphor sheet completely covers the light-emitting surface of the LED chip while avoiding dimensional deviations affecting the production of the light-blocking layer, significantly improving the consistency of LED chip luminous performance. A transparent organic silicone layer is placed around the phosphor layer, which can effectively prevent moisture from entering the phosphor layer during use, improving the long-term reliability of the product. No complicated waterproof sealing and drying processes are required, and no cutting process is needed, reducing production difficulty and cost, minimizing process defects, and making it suitable for large-scale industrial mass production. The embodiments disclosed herein provide light-emitting devices that can be widely used in complex and precise light control applications such as mini backlights, automotive display backlights, and adaptive driving beams (ADB).

[0157] Table 1

[0158] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A light-emitting unit, characterized in that, The light-emitting unit includes: a light-emitting diode chip (102), a phosphor sheet (103), and a light-blocking layer (104). The light-blocking layer (104) surrounds the light-emitting diode chip (102), the light-blocking layer (104) has a first groove (1001), the phosphor (103) is located on the light-emitting surface of the light-emitting diode chip (102), and the phosphor (103) is located in the first groove (1001); The phosphor sheet (103) includes a transparent protective layer (1031) and a phosphor layer (1032). The transparent protective layer (1031) has a second groove (1002). The phosphor layer (1032) is located in the second groove (1002). The sidewall of the second groove (1002) is located between the sidewall of the phosphor layer (1032) and the sidewall of the first groove (1001). The phosphor layer (1032) is located between the bottom surface of the light-emitting diode chip (102) and the first groove (1001).

2. The light-emitting unit according to claim 1, characterized in that, The transparent protective layer (1031) is a transparent silicone layer.

3. The light-emitting unit according to claim 1 or 2, characterized in that, The light-emitting diode chip (102) is projected onto the light-emitting surface, and the second groove (1002) is located inside the projection of the light-emitting surface. The second groove (1002) is located in the orthographic projection of the light-emitting surface, inside the orthographic projection of the first groove (1001) on the light-emitting surface.

4. The light-emitting unit according to claim 1 or 2, characterized in that, The thickness of the fluorescent sheet (103) is equal to the depth of the first groove (1001).

5. A method for manufacturing a light-emitting unit, characterized in that, The method for manufacturing the light-emitting unit includes: A fluorescent sheet is fabricated, the fluorescent sheet comprising a transparent protective layer and a phosphor layer, the transparent protective layer having a second groove, and the phosphor layer being located within the second groove; The phosphor sheet is bonded to the light-emitting diode chip, with the phosphor sheet located on the light-emitting surface of the light-emitting diode chip, and the phosphor layer in contact with the light-emitting diode chip; A light-blocking layer is formed around the light-emitting diode chip. The light-blocking layer has a first groove, and the phosphor is located in the first groove. The sidewall of the second groove is located between the phosphor layer and the sidewall of the first groove. The phosphor layer is located between the bottom surface of the light-emitting diode chip and the first groove.

6. The method for manufacturing the light-emitting unit according to claim 5, characterized in that, The fabrication of the fluorescent sheet includes: The transparent silicone is filled into the first mold cavity; The first mold is subjected to molding and heating to solidify the transparent silicone to form the transparent protective layer, the transparent protective layer including the second groove; Remove the first mold; The phosphor is mixed with organosilicon gel, and after vacuum degassing, it is injected into the second groove to form the phosphor layer.

7. The method for manufacturing the light-emitting unit according to claim 6, characterized in that, The fabrication of the fluorescent sheet also includes: The phosphor layer is first baked at a first temperature; The phosphor layer is baked a second time at a second temperature, wherein the first temperature is lower than the second temperature; The phosphor layer is baked a third time at a third temperature, where the second temperature is lower than the third temperature.

8. The method for manufacturing the light-emitting unit according to claim 7, characterized in that, The first temperature is 70~90℃, the second temperature is 110~130℃, and the third temperature is 140~160℃; The first baking time is 20-40 minutes, the second baking time is 50-70 minutes, and the third baking time is 20-40 minutes.

9. The method for manufacturing a light-emitting unit according to any one of claims 5 to 8, characterized in that, Bonding the fluorescent sheet to the light-emitting diode chip includes: A transparent silicone adhesive is uniformly coated on the light-emitting surface of the light-emitting diode chip; The fluorescent sheet is precisely aligned and bonded, and then hot-pressed using a vacuum hot-pressing process. The transparent silicone adhesive is cured by heating, so that the light-emitting diode chip and the phosphor are bonded together.

10. The method for manufacturing a light-emitting unit according to any one of claims 5 to 8, characterized in that, A light-blocking layer is formed around the light-emitting diode chip, including: The light-emitting diode chip with the fluorescent sheet attached is placed into the second mold cavity, and nano-titanium dioxide white glue is coated around the light-emitting diode chip and the fluorescent sheet to form the light-blocking layer; The second mold is heated to solidify the light-blocking layer; Remove the second mold.

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