Patent Application
20240136482
This Application claims priority of Taiwan Patent Application No. 111140186, filed on Oct. 24, 2022, and the entirety of which is incorporated by reference herein.
The present application relates to a composite encapsulation material for light-emitting diodes (LED) and optical devices that include the composite encapsulation material in particular.
Light-emitting diode (LED) light sources have advantages of high efficiency, long product lifecycle, and no harmful substances such as mercury (Hg). With the continuous improvement of technology in the field of light-emitting diodes, the brightness and lifetime of light-emitting diodes have been greatly improved, making the application of light-emitting diodes more and more extensive. The old light sources used in applications from outdoor lighting such as street lights to indoor lighting such as decorative lights are generally being replaced by light-emitting diodes.
Light-emitting diodes need to be packaged in a suitable form for an end product to be put into practical use. Generally, the function of packaging is to provide sufficient protection for the chip to prevent the chip from being exposed to the air for a long time, or from mechanical damage so as to improve the stability of the chip. It is also necessary for light-emitting diode packaging to have good light extraction efficiency (LEE) and good heat dissipation. Good packaging can make light-emitting diodes have better luminous efficiency and heat dissipation, thereby improving the lifetime of light-emitting diodes.
In addition, packaging is also a key process in the manufacturing of white light-emitting diodes. The light-emitting mechanism of semiconductor materials determines that a single light-emitting diode chip cannot emit white light with a continuous spectrum, so in the manufacturing process, two or more complementary colors of light must be mixed to form white light. At present, there are three main methods to realize white light-emitting diodes: (1) blue light-emitting diodes with yellow (YAG) phosphor powder, (2) RGB three-color light-emitting diodes, (3) ultraviolet light-emitting diodes with multi-color phosphor powders. The realization of white light-emitting diodes by packaging, good process precision control, and good materials and equipment are the guarantee for the stability of white light-emitting diode devices.
At present, conventional light-emitting diode packaging technology uses a phosphor encapsulation process, that is, the phosphor powder and the glue are mixed with a certain proportion, and then the phosphor powder glue is coated on the surface of light-emitting diode by an automatic dispenser machine. By using this method, the optical performance of the light-emitting chip is improved. However, the density of the phosphor powder is higher than that of the glue, and there is a certain density difference between the two. When the two substances are mixed together, the phosphor powder can be sedimented and dispersed in the phosphor powder glue unevenly, which makes the light to be mixed unevenly, so the white light emitted by the component is not uniform, and there can be blue and yellow ring phenomenon appearing around the light spot, which greatly affects product performance.
In addition, the conventional encapsulation material have better adhesion due to the better wetting effect of the glue material and the substrate. Therefore, it is difficult for the glue material to maintain the shape after dispensing, which means the glue material can be spread and cannot form an ideal lens itself, and therefore affects the light extraction efficiency.
An embodiment of the present application provides a composite encapsulation material, which comprises: (A) a polymer glue material; and (B) a viscosity modifier. The viscosity modifier (B) has a functional group that is capable of forming a non-covalent interaction with the polymer glue material (A). At room temperature, the ratio (log(η0)/log(η∞)) of the a logarithm of the a viscosity (log(η0)) of the composite encapsulation material at a shear rate of 1×10−3 s−1 to the a logarithm of the a viscosity (log(η∞)) of the composite encapsulation material at a shear rate of 1×102 s−1 is 1.1-2.5.
An embodiment of the present application provides an optical device, which comprises the composite encapsulation material in the present disclosure.
Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
Some variations of the embodiments are described below. In the different drawings and described embodiments, like reference numerals are used to designate like elements. It is understood that additional steps may be provided before, during, and after the method, and that some recited steps may be substituted or deleted in other embodiments of the method.
Further, spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.
Further, when a number or a range of numbers is described with “about”, “approximate”, and the like, the term is intended to encompass numbers that are within a reasonable range considering variations that inherently arise during manufacturing as understood by one of ordinary skill in the art.
In the present embodiment, the viscosity is defined as the viscosity value measured under the environment of temperature 25° C.±5° C., humidity 50±10% RH and standard pressure (100 kPa). Even if the viscosity values are measured outside the range above, as long as they are adjusted to the temperature 25° C.±5° C., humidity 50±10% RH, and standard pressure falls within the range specified in the present disclosure, then they are also included in the scope of the present embodiment. In addition, the terms “standard temperature” and “room temperature” herein refer to a temperature of about 20° C. to 30° C.
In the present embodiment, “γ” refers to the shear rate with the unit of s−1, and “η” refers to the viscosity with the unit of mPa·s. “η0” refers to the viscosity of the encapsulation material when the shear rate is 1×10−3 s−1 at room temperature (25° C.±5° C.); “η∞” refers to the viscosity of the encapsulation material at room temperature when the shear rate is 1×102 s−1. In addition, “log(η0)” refers to the base 10 logarithm of η0; “log(η∞)” refers to the base 10 logarithm of η28; “log(γ)” refers to the base 10 logarithm of γ.
A composite encapsulation material are provided, which includes (A) a polymer glue material and (B) a viscosity modifier. The viscosity modifier (B) has a functional group capable of forming non-covalent forces with the polymer glue material (A). At room temperature, the ratio (log(η0)/log(η∞)) of the logarithm of the viscosity (η0) of the composite encapsulation material at a shear rate of 1×10−3 s−1 to the logarithm of the viscosity (η∞) of the composite encapsulation material at a shear rate of 1×102 s−1 is 1.1-2.5.
Referring to
Since the viscosity of the composite encapsulation material in the present embodiment is close to a constant value at a shear rate under 1×10−3 s−1, when the shear rate is below 1×10−3 s−1, the composite encapsulation material can be regarded as under static state (unstressed state). Therefore, the η0 is set as the viscosity at a shear rate of 1×10−3 s−1. As the shear rate increases (the shear rate is greater than 1×10−3 s−1), the external force on the composite encapsulation material increases, and the molecules of the composite encapsulation material are disturbed (considered as being in a stressed state), so that the non-covalent interaction between the molecules is weakened, resulting in a gradual decrease in viscosity. When the added amount of modifiers reaches a certain level, the slurry separation due to high rotation speed in the measurement may occur, resulting in poor stability of the measured value and losing the value of material judgment. Therefore, the η∞ is set as the viscosity at a shear rate of 1×10−2 s−11.
In some embodiments, the polymer glue material (A) includes siloxane bonds, carbon-hydrogen bonds, or a combination thereof. In some embodiments, the polymer glue material (A) includes silicone resin, epoxy resin, fluororesin, or a combination thereof.
The silicone resin may be, for example, a resin containing siloxane bonds and having an organic functional group such as an alkyl group or an aromatic group as a constituent unit. The aforementioned alkyl group is not limited particularly to such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group. The aforementioned aromatic group is not limited particularly to such as a phenyl group, a benzyl group, or the like. Specifically, the silicone resin may be, for example, dimethylpolysiloxane, methylphenylpolysiloxane, diphenylpolysiloxane. In addition, the silicone resin may also include epoxy modified silicone resin, alkyd modified silicone resin, acrylic modified silicone resin, polyester modified silicone resin, etc., or a combination thereof.
Above-mentioned epoxy resin, can be a bisphenol-A based epoxy resin, a bisphenol-F based epoxy resin, a phenol novolac epoxy, a tetrabromobisphenol epoxy resin, and a rubber modified epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin, or a combination thereof.
Above-mentioned fluororesin can be polyvinyl fluoride (PVF), polyvinylidene difluoride (PVDF), polytrifluoroethylene (PTrFE), polychlorotrifluoroethylene (PCTFE), polytetrafluoroethylene (PTFE); copolymer can be ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-chlorotrifluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoropropyl vinyl ether copolymer, or a combination thereof.
In addition, the polymer glue material (A) may also include other resins, such as acrylic resins, vinyl ester resin, urea resins, polyimide resin, polyphenylene sulfide, or a combination thereof. Examples of acrylic resins include poly(methyl methacrylate) (PMMA) and poly(ethylene glycol dimethacrylate) (PEGMA). Examples of vinyl resins include poly(vinyl acetate) (PVA) and poly(divinylbenzene) (PDVB).
In some embodiments, other additives maybe included in the polymer glue material (A), such as curing agent, curing accelerator, silane coupling agent, flame retardant, flame retardant auxiliary agent, release agent, ion capture agents, pigments/colorants, stress reducers, adhesives, or a combination thereof.
In some embodiments, the functional groups of the viscosity modifier (B) that are capable of forming a non-covalent force with the polymer glue material (A) include —OH, ═NH, —NH2, halogen, hydrocarbon chain, or a combination thereof. In some embodiments, the viscosity modifier (B) includes a polymer material, a nanomaterial, or a combination thereof.
In some embodiments, the polymer material in the viscosity modifier (B) includes polyamide wax, organic bentonite clay, hydrogenated castor oil, or a combination thereof. The organic bentonite may be bentonite having cetyltrimethylammonium ions, bentonite having tetramethylammonium ions, or the like. According to some embodiments, based on 100 parts by weight of the polymer glue material (A), the polymer material used as the viscosity modifier (B) may be 1-100 parts by weight, such as 5-95 parts by weight, 10-90 parts by weight, 15-85 parts by weight, 20-80 parts by weight, 25-75 parts by weight, 30-70 parts by weight, 35-60 parts by weight, 40-55 parts by weight, or 45-50 parts by weight.
In some embodiments, the particle size of the nanomaterial in the viscosity modifier (B) may be 1 nm-500 nm, such as 3 nm-480 nm, 5 nm-450 nm, 8 nm-420 nm, 10 nm-400 nm, 15 nm-380 nm, 20 nm-350 nm, 25 nm-320 nm, 30 nm-300 nm, 35 nm-250 nm, 40 nm-200 nm, 50 nm-150 nm, 55 nm-100 nm, 60 nm-95 nm, 70 nm-90 nm, or 75 nm-85 nm. According to some embodiments, based on 100 parts by weight of the polymer glue material (A), the nanomaterial used as the viscosity modifier (B) may be 0.1-130 parts by weight, such as 0.5-125 parts by weight, 1.5-121 parts by weight, 5-115 parts by weight, 10-110 parts by weight, 15-105 parts by weight, 20-100 parts by weight, 25-95 parts by weight, 30-90 parts by weight, 35-85 parts by weight, 40-80 parts by weight, 45-75 parts by weight, 50-70 parts by weight, or 55-60 parts by weight.
In some embodiments, the nanomaterials include luminescent materials, non-luminescent materials, or a combination thereof. In some embodiments, the non-luminescent material includes TiO2, SiO2, Al2O3, or a combination thereof. In some embodiments, the luminescent material includes quantum dots.
Different functional groups may be introduced to the non-luminescent material through surface modification. For example, it can be conducted by hydrophobic surface modification, hydrophilic surface modification, and the like. For example, the surface of the non-luminescent material may be coated with trimethylchlorosilane, triethylchlorosilane, triphenylchlorosilane, dimethylchlorosilane, dimethyldichlorosilane, polydimethylsiloxane, hydroxyl polydimethylsiloxane, poly (methyl methacrylate), fatty acid, silicon oxide, aluminum oxide, etc. According to some embodiments, the non-luminescent material is capable of forming non-covalent interaction such as hydrogen bonds, van der Waals forces, ionic bonds, and hydrophobic interactions with the polymer material (A) in the present embodiment.
The quantum dots may comprise II-VI semiconductor compounds, III-V semiconductor compounds, IV-VI semiconductor compounds, or a combination thereof. The structure of quantum dots may include the core region that mainly emits light and the shell that covers the core region. The material of the core region may comprise zinc sulfide (ZnS), zinc selenide (ZnSe), zinc telluride (ZnTe), zinc oxide (ZnO), cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium telluride (CdTe), gallium nitride (GaN), gallium phosphide (GaP), gallium selenide (GaSe), gallium antimonide (GaSb), gallium arsenide (GaAs), aluminum nitride (AlN), aluminum phosphide (AlP), aluminum arsenide (AlAs), indium phosphide (InP), indium arsenide (InAs), tellurium (Te), lead sulfide (PbS), indium antimonide (InSb), lead telluride (PbTe), lead selenide (PbSe), antimony telluride (SbTe), zinc cadmium selenide (ZnCdSe), zinc cadmium selenium sulfide (ZnCdSeS), copper indium sulfide (CuInS), or a combination thereof. The material of the shell and the material of the core region match each other (e.g., the lattice constants of the materials of the core region and the shell need to match).
Specifically, with respect to the material composition of the shell, in addition to taking the lattice constant match for the material of the core region into consideration, another consideration is forming a high energy barrier region around the core region to increase the quantum yield. In order to satisfy these two properties at the same time, the structure and/or composition of the shell can be modified to reduce the stress of the core region and the shell on the one hand and increase the energy barrier on the other hand. The structure of the shell may be a single-layer structure, a multi-layer structure or a material composition gradient structure.
In one embodiment, the core region is cadmium selenide, and the shell is a single layer of zinc sulfide. In another embodiment, the core region is cadmium selenide, and the shell includes the inner layer of (cadmium, zinc) (sulfur, selenium) and the outer layer of zinc sulfide.
In another embodiment, the core is cadmium selenide, the shell includes the inner layer of cadmium sulfide, the middle graded layer of Zn0.25Cd0.75S/Zn0.5Cd0.5S/Zn0.75Cd0.25S, and the outer layer of zinc sulfide. In some embodiments, the quantum dots can form non-covalent interactions such as ionic bonds, van der Waals forces, hydrogen bonds, and hydrophilic-hydrophobic interactions with the polymer glue material (A).
In some embodiments, the composite encapsulation material further include phosphor, and the type of phosphor is not restricted particularly. For example, it may be yellow, red, green, or blue light-emitting phosphor powders widely used in light-emitting diodes, such as oxide-based phosphor powder, nitrogen oxide-based phosphor powder, nitride-based phosphor powder, sulfide-based phosphor powder, and oxysulfide-based phosphor powder. Phosphor powder materials may be, for example, Y3Al5O12:Ce, Gd3Ga5O12:Ce, Lu3Al5O12:Ce, (Lu, Y)3Al5O12:Ce, Tb3Al5O12:Ce, SrS:Eu, SrGa2S4:Eu, (Sr, Ca, Ba)(Al, Ga)2S4:Eu, (Ca, Sr)S:(Eu, Mn), (Ca, Sr)S:Ce, (Ba, Sr, Ca)2SiO4:Eu, (Ca, Sr, Ba)Si2O2N2:Eu, (Sr, Ba, Ca)2Si5N8:Eu, (Sr, Ba, Ca)(Al, Ga)SiN3:Eu, SrLiAl3N4:Eu, Ba2LiSi7AlN12:Eu, K2SiF6:Mn, K2TiF6:Mn, K2SnF6:Mn, or a combination thereof.
Referring to
The encapsulation material disclosed in this embodiment can be applied to different light-emitting diode package types, such as surface mount device (surface mount device, SMD) and chip direct bonding (chip on board, COB), to form an optical device including the composite encapsulation material in the present embodiment. In some embodiments, the optical device includes a light-emitting unit, and the composite encapsulation material in the present embodiment covers the light-emitting unit in the optical device. In some embodiments, the light-emitting unit may be a light-emitting diode chip. In some embodiments, the optical device further comprises an optical unit, wherein the optical unit is made of the composite encapsulation material. In some embodiments, the optical unit is a lens.
In contrast, the molecular structure of conventional encapsulation material does not change whether it is under stress and conventional encapsulation material has better adhesion property due to the good wetting effect of the glue material and the substrate. Therefore, the conventional encapsulation material has difficulty maintaining the shape after dispensing and other processes. For example, the glue material may spread so the conventional encapsulation material cannot form an ideal lens shape by itself, which affects the light extraction efficiency.
In contrast, the conventional encapsulation material is filled in the same type of dispensing syringe. After standing at room temperature for 4 hours, the delamination can be observed obviously and the phosphor powder in the conventional encapsulation material sediments.
The present embodiment is described in more detail herein based on various examples, but the present embodiment is not limited thereto. The “parts” in the table refers to “parts by weight (wt %)”, and each example regards the polymer glue material as 100 parts by weight.
The rheometer (MCR-102) manufactured by Anton Paar was used to measure the viscosity of the encapsulation material of different examples at 25° C. A Parallel-Plate with a diameter of 25 mm was used, the measurement gap was 250 μm, scan measuring is conducted at a shear rate of 0.001 s−1-1000 s−1, and the value of log(η0)/log(η∞) value was calculated from the obtained data.
Neither luminescent material nor non-luminescent nanomaterial was added to Comparative Example A0, and Comparative Example A0 was used as a comparison standard.
Non-luminescent nanomaterial was added in Example A1. According to the formula shown in table 1, 100 parts by weight (Wt %) of the Silicone-A and 25 parts by weight (Wt %) of the TiO2-A were substantially mixed at room temperature by stirring in the same direction at for 10-15 minutes. Then the stirred encapsulation material was put into a vacuum apparatus for degassing, and the vacuum state at room temperature was maintained until there were no air bubbles in the encapsulation material.
Non-luminescent nanomaterials were added in Examples A2 and A8. Examples A2 and A8 were prepared in the same way as Example A1 except that the types and proportions of the added non-luminescent nanomaterial were adjusted according to Table 1.
Luminescent materials were added in Example A3. According to the formula shown in Table 1, 100 parts by weight (wt %) of Silicone-A, 25 parts by weight of the green phosphor powder and 25 parts by weight of the red phosphor powder were mixed in Example 3. After 10-15 minutes of stirring in the same direction, which makes the materials be substantially mixed, the stirred encapsulation material was put into a vacuum apparatus for degassing, and the vacuum state at room temperature was maintained until there were no air bubbles in the encapsulation material.
Luminescent material and non-luminescent nanomaterial were added in Example A4. According to the formula shown in Table 1, 100 parts by weight of Silicone-A, 2 parts by weight of SiO2-A were fully mixed by stirring in the same direction for 10-15 minutes. Then, 25 parts by weight of green phosphor powder and 25 parts by weight of red phosphor powder were added and fully mixed by 10-15 minutes of stirring in the same direction. The stirred encapsulation material was put into a vacuum apparatus for degassing, and the vacuum state at room temperature was maintained until there were no air bubbles in the encapsulation material.
Luminescent materials were added in Examples A5-A7, except that the ratio of the added luminescent materials were adjusted according to Table 1, Examples A5-A7 were prepared in the same manner as in Example A3.
Through the viscosity of different examples in Experimental group 1, the encapsulation material with substantially same ratio of powder were compared.
First, Examples A1-A2 and A8 and comparative example A0 were compared. There were TiO2-A with particle size 250 nm added in both Examples A1-A2. In comparison to comparative example A0, the value of (log(η0)/log(η∞)) of the composite encapsulation material of A1-A2 increased significantly, and the value of (log(η0)/log(η∞)) rose when the the amount of TiO2-A added was also increased. In contrast, though there was non-luminescent nanomaterial of the same 50 parts by weight added in Example A8 as in Example A2, the particle size of SiO2-D was 10 μm, the surface of SiO2-D was untreated, and thus it was difficult to increase the value of (log(η0)/log(η∞)) of the encapsulation material.
Next, Examples A3-A7 and comparative Example A0 were compared. There were 50 parts by weight of the luminescent materials added in all Example A3-A7. 25 parts by weight of green phosphor powder and 25 parts by weight of red phosphor powder were added in Example A3, but the particle size of the two were both over 500 nm, which has little effect on the value of (log(η0)/log(η∞)) of the encapsulation material. In contrast, in Example A4, in addition to the material in Example A3, 2 parts by weight of the SiO2-A was added, which has the particle size of 7 nm and can increase the value of (log(η0)/log(η∞)) of the encapsulation material significantly. Similarly, there were not many changes in the values of (log(η0)/log(η∞)) of Example 5 with 50 parts by weight of the green phosphor powder added and of Example 6 with 50 parts by weight of the red phosphor powder added, in comparison to the comparative Example A0. On the other hand, 50 parts by weight of the quantum dot with the particle size of 50 nm was added to Example 7, and the quantum dot significantly affected the value of (log(η0)/log(η∞)) of the encapsulation material.
In summary, when the size of the powder material added to the encapsulation material is greater than 500 nm, the (log(η0)/log(η∞)) value of the encapsulation material cannot be greater than 1.1, so the phosphor powder used in conventional light-emitting diodes cannot improve the viscosity of the encapsulation material.
In Table 2, “x” refers to no anti-sedimentation effect; “Δ” refers to slight anti-settling effect; “O” refers to good anti-settling effect.
Neither luminescent material nor non-luminescent nanomaterial was added in comparative example B0, which was used as the standard in comparison.
The non-luminescent nanomaterial was added in Example B1. According to the formula shown in Table 2, 100 parts by weight of Silicone-B and 1 part by weight of SiO2-A were fully mixed by stirring in the same direction for 10-15 minutes. Then the mixed composite encapsulation material was put into a vacuum apparatus for degassing, and the vacuum state at room temperature was maintained until there were no air bubbles in the encapsulation material.
Except the type and ratio of the added SiO2 were changed, Example B2-B4 were prepared in the same manner as in the Example B1.
Then, a part of the prepared examples B0-B4 were tested for viscosity, and the remainder each were mixed with 25 parts by weight of green phosphor powder (30 μm). After stirring in the same direction for 10-15 minutes, the materials are substantially mixed. The stirred encapsulation material were put into a vacuum apparatus for degassing, and the vacuum state at room temperature was maintained until there were no air bubbles in the encapsulation material. The degassed materials were injected into the dispensing syringes and leave stand at room temperature for 4 hours to observe whether the phosphor powder sediment.
The anti-sedimentation effect was compared in experimental group 2 by adding different SiO2 material. According to Table 2, it can be seen that in comparison with the comparative example B0 without SiO2, the (log(η0)/log(η∞)) values of the examples B1-B4 with SiO2 were significantly improved.
The Examples B1-B3 and the comparative example B0 were compared. With the same amount of SiO2 added in example B1-B3, the SiO2-A added in Example B1 had no surface treatment, the SiO2-B added in Example B2 were coated with dimethyl dichlorosilane and the SiO2-C added in Example B3 were coated with polydimethylsiloxane. The different functional group on the SiO2 resulted in different values of (log(η0)/log(η∞)) of Examples B1-B3. In addition, since the bonding force of hydrogen bond of the SiO2-A without coating in example B1 was stronger, it was easier for Example B1 to form a tangled net structure, and the value of (log(η0)/log(η∞)) of Example B1 is greater than that of Example B2.
Next, Examples B3 and B4 were compared. SiO2-C was added in both Examples B3-B4. The polydimethylsiloxane coating of SiO2-C can form non-covalent interaction with polymer glue material, hence the higher the ratio of the added SiO2-C had, the stronger the bonding forcing between the encapsulation material was, which made the value of (log(η0)/log(η∞)) of the encapsulation material greater and the effect of the anti-sedimentation better.
In summary, with the same ratio of different types of SiO2, the value of (log(η0)/log(η∞)) of the encapsulation material varied due to the different surface condition of SiO2. This is because different non-covalent bonds were formed between SiO2 particles and between SiO2 particles and polymer glue material, resulting in different molecular structure entanglement.
Neither luminescent material nor non-luminescent nanomaterial was added in Comparative example C0 and D0, and the two were used as standard in comparison.
The non-luminescent nanomaterial was added in Example C1. According to the formula shown in Table 3, 100 parts by weigh of Silicone-C and 1 part by weight of SiO2-A were substantially mixed after stirring in the same direction for 10-15 minutes. Then the mixed composite encapsulation material was put into a vacuum apparatus for degassing, and the vacuum state at room temperature was maintained until there were no air bubbles in the encapsulation material.
Except for the change of the amount of SiO2-A added according to Table 3, Examples C2-C4 were prepared in the same manner as in Example C1.
Except for the change of the polymer glue material to Silicone-D according to Table 3, Examples D1-D3 were prepared in the same manner as in Example C1.
A part of the prepared encapsulation material was tested for viscosity, and other part of that is used for dispensing. A dispenser was used to control the dispensing volume to 6 μL, and dispensed the encapsulation material on the die-bonded substrate at room temperature. After dispensing, the encapsulation material forms the shape of the lens on the substrate, and the aspect ratio of the formed lens is measured.
Examples C1-C3 and D1-D3 in the experimental group 3 can form transparent lens on the substrate, and when the value of log(η0)/log(η∞) of the encapsulation material was about 1.5, the aspect ratio of the formed lens was about 0.10-0.20. When the value of log(η0)/log(η∞) of the encapsulation material was about 2.0, the aspect ratio of the formed lens was about 0.4-0.6; when the value of log(η0)/log(η∞)) of the encapsulation material was greater than 2.0, the aspect ratio of the formed lens was about 0.7-1.0.
To sum up, since being under unstressed state, the molecular structure of the encapsulation material in the present embodiment entangled to form a net structure, which limits the spreading state of the polymer glue material, so it can form a lens shape on the substrate (as shown in
The non-luminescent nanomaterial was added in Example C5. According to the formula shown in Table 4, 100 parts by weigh of Silicone-C and 1 part by weight of SiO2-A were substantially mixed after stifling in the same direction for 10-15 minutes. Then 40 parts by weight of the TiO2-A was added and substantially mixed by stifling in the same direction for 10-15 minutes. Then the mixed composite encapsulation material was put into a vacuum apparatus for degassing, and the vacuum state at room temperature was maintained until there were no air bubbles in the encapsulation material.
Except for the change of the amount of SiO2-A added according to Table 4, Example C5 was prepared in the same manner as in Example C5.
Part of the prepared encapsulation material was tested for viscosity, and other part was used for dispensing. A dispenser was used to control the dispensing volume to 6 μL, and dispensed the encapsulation material on the die-bonded substrate at room temperature. After dispensing, the encapsulation material forms the shape of the lens on the substrate, and the aspect ratio of the formed lens is measured.
Due to the addition of TiO2, Examples C5 and C6 in the experimental group 4 can form a white lens on the substrate (as shown in
According to the formula shown in Table 5, 100 parts by weigh of TiO2-A was added in 100 parts by weight of Silicone-D in several portions and stirred. Before each time of adding TiO2-A, the materials were substantially mixed. After TiO2-A were substantially mixed after stifling in the same direction for 10-15 minutes, the mixed composite encapsulation material was put into a vacuum apparatus for degassing, and the vacuum state at room temperature was maintained until there were no air bubbles in the encapsulation material.
Except for the change of the amount of TiO2-A added according to Table 5, Example D5 was prepared in the same manner as in Example D4.
In the experimental group 5, the examples with high proportion of TiO 2 added were compared. 100 parts by weight of TiO2-A was added in Example D4, and 120 parts by weight of TiO2-A was added in Example D5. The value of log(η0)/log(η∞) of Examples D4-D5 both fell above 1.5. The log(η0)/log(η∞) of Example D5 decreased in comparison with that of Example D4, which was due to the normal fluctuation of value in the viscosity measurement.
Then referring to
From the above examples and comparative examples, it can be seen that the composite encapsulation material in the present embodiment has an anti-sedimentation effect and can form a lens shape by itself, while maintaining its processability.
In the present embodiment, the encapsulation material has a tangled net structures when a viscosity modifier is added, which has a functional group that can form a non-covalent interaction with the polymer glue material in the encapsulation material. encapsulation material Therefore, under unstressed state, the composite encapsulation material can maintain its shape and avoid the sedimentation of phosphor powder therein.
In addition, the viscosity of the encapsulation material in the present embodiment decreases when being stressed, so that the composite encapsulation material can be used in packaging processes such as dispensing.
While the invention has been described by way of example and in terms of the preferred embodiments, it should be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
| Number | Date | Country | Kind |
|---|---|---|---|
| 111140186 | Oct 2022 | TW | national |
