Light-emitting substrate, preparation method thereof, backlight module and display device
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BOE TECHNOLOGY GROUP CO LTD
- Filing Date
- 2022-05-11
- Publication Date
- 2026-07-03
Smart Images
Figure CN117396801B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of display technology, and in particular to a light-emitting substrate and its preparation method, a backlight module, and a display device. Background Technology
[0002] With the rise and increasing maturity of Organic Light-Emitting Diode (OLED) technology, OLED products have gradually become the new favorite in the market. However, OLED products are expensive and have poor reliability. In order to achieve the high contrast and thinness of OLED products, while retaining the price and reliability advantages of Liquid Crystal Display (LCD) products, micro-LEDs have emerged as backlight products.
[0003] Micro LEDs include micro light-emitting diodes (Micro LEDs) and sub-millimeter light-emitting diodes (Mini LEDs). Micro LEDs have a size (e.g., length) of less than 100 micrometers, such as 10 to 50 micrometers; Mini LEDs have a size (e.g., length) of 100 to 500 micrometers, such as 100 to 120 micrometers.
[0004] LCD panels equipped with micro-LED backlighting offer advantages such as high peak brightness, high contrast, low power consumption, and high reliability, and have broad development prospects. Summary of the Invention
[0005] On the one hand, a light-emitting substrate is provided, including a light-emitting component and a reflective layer.
[0006] The light-emitting component includes a substrate and a plurality of light-emitting devices arranged in an array on the substrate. A reflective layer is located on the light-emitting side of the light-emitting component, and the reflective layer has a plurality of openings arranged in an array, with the plurality of light-emitting devices located within the plurality of openings. The distance between the center of each light-emitting device and the center of the opening containing the light-emitting device is 0 mm to 0.1 mm in a predetermined direction; the predetermined direction is parallel to one side of the substrate.
[0007] In some embodiments, the reflective layer has a first side and a second side, both of which are perpendicular to the preset direction. Within the region between the first side and the centerline of the reflective layer parallel to the first side, the distance between the center of the light-emitting device and the center of the opening where the light-emitting device is located in the preset direction is 0 mm to 0.05 mm.
[0008] In some embodiments, the aperture of the opening gradually decreases along the thickness direction of the substrate, from the end of the opening away from the substrate to the end of the opening closer to the substrate.
[0009] In some embodiments, the angle between the sidewall of the opening and the substrate is an obtuse angle.
[0010] In some embodiments, the light-emitting substrate further includes a plurality of protective adhesives. At least a portion of the protective adhesives is disposed within the opening, and the protective adhesives encapsulate the light-emitting device located within the opening.
[0011] In some embodiments, the protective adhesive fills and covers the opening; among the plurality of protective adhesives, adjacent protective adhesives are spaced apart.
[0012] In some embodiments, the material of the protective adhesive includes a UV-curable adhesive.
[0013] In some embodiments, the curing temperature of the protective adhesive is lower than the glass transition temperature of the reflective layer.
[0014] In some embodiments, the protective adhesive is made of a methylvinylsiloxane-coordinated platinum catalyst and / or a platinum-divinyltetramethyldisiloxane catalyst.
[0015] In some embodiments, the thixotropic index of the protective adhesive is 4.9 to 5.9.
[0016] In some embodiments, the light-emitting substrate further includes an adhesive layer. The adhesive layer is disposed on the side of the reflective layer near the light-emitting component, and the adhesive layer is disposed away from the opening; the side boundary of the adhesive layer extends beyond the side boundary of the reflective layer.
[0017] In some embodiments, the extended portion of the adhesive layer includes a first sub-region and a second sub-region that are sequentially located away from the center of the adhesive layer, the second sub-region being disposed around the first sub-region.
[0018] In some embodiments, the width of the first sub-region is 0.002mm to 0.005mm, and the width d4 of the second sub-region is 0.5×A×L3, where A is the shrinkage rate of the reflective layer and L3 is the length of the reflective layer along the preset direction.
[0019] In some embodiments, the light-emitting substrate further includes a white varnish layer. The white varnish layer is disposed between the substrate and the reflective layer, and the white varnish layer has a plurality of openings through which the light-emitting device is exposed.
[0020] On the other hand, a method for fabricating a light-emitting substrate is provided. The method includes: providing a light-emitting component, the light-emitting component including a substrate and a plurality of light-emitting devices arranged in an array on the substrate; the distance between the centers of the two farthest light-emitting devices on the light-emitting component along a predetermined direction is a first dimension. A reflective layer is provided, the reflective layer having a plurality of openings arranged in an array, the number of openings being equal to the number of light-emitting devices; the distance between the centers of the two farthest openings on the reflective layer along the predetermined direction is a second dimension; the second dimension is smaller than the first dimension. The reflective layer is attached to the light-emitting component along the predetermined direction, such that the plurality of light-emitting devices are respectively located within the plurality of openings.
[0021] In some embodiments, the difference between the first dimension and the second dimension is ΔL = S × L; where S is the elongation coefficient of the reflective layer and L is the value of the second dimension.
[0022] In some embodiments, the light-emitting component includes multiple rows of light-emitting devices, each row comprising a plurality of light-emitting devices arranged sequentially along the preset direction. Before the reflective layer is attached, the distance between the centers of two adjacent openings in the reflective layer along the preset direction is... Where L2 is the distance between the centers of two adjacent light-emitting devices in a row, and n is the number of light-emitting devices included in a row.
[0023] In some embodiments, after attaching the reflective layer to the light-emitting component along the preset direction, the process further includes: pre-baking the light-emitting component to which the reflective layer is attached; applying a protective adhesive inside and above the opening; and curing the protective adhesive.
[0024] In some embodiments, the pre-baking temperature is approximately 140°C to 160°C, and the baking time is approximately 10 min to 30 min. The curing temperature is approximately 140°C to 160°C, and the curing time is approximately 50 min to 70 min.
[0025] In some embodiments, after attaching the reflective layer to the light-emitting component along the preset direction, the method further includes: applying a protective adhesive inside and above the opening; the curing temperature of the protective adhesive is lower than the glass transition temperature of the reflective layer. The protective adhesive is then cured; the curing temperature is approximately 80°C to 100°C, and the curing time is approximately 50 min to 70 min.
[0026] On the other hand, a backlight module is provided, including an optical film and a light-emitting substrate as described in any of the foregoing embodiments. The optical film is disposed on the light-emitting side of the light-emitting substrate.
[0027] On the other hand, a display device is provided, including a display panel and a backlight module as described in any of the foregoing embodiments. The backlight module is disposed on the non-light-emitting side of the display panel. Attached Figure Description
[0028] To more clearly illustrate the technical solutions in this disclosure, the accompanying drawings used in some embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not intended to limit the actual size of the product, the actual flow of the method, the actual timing of the signals, etc. involved in the embodiments of this disclosure.
[0029] Figure 1 This is a top view of a light-emitting substrate provided according to some embodiments;
[0030] Figure 2 This is a top view of a light-emitting component provided according to some embodiments;
[0031] Figure 3 This is a top view of a reflective layer according to some embodiments;
[0032] Figure 4 for Figure 1 Enlarged view of the area corresponding to the dashed box B in the middle;
[0033] Figure 5 For along Figure 1 A cross-sectional view of the mid-section line A-A';
[0034] Figure 6 For along Figure 1 Another cross-sectional view of the mid-section line A-A';
[0035] Figure 7 For along Figure 1 Another cross-sectional view of the mid-section line A-A';
[0036] Figure 8 For along Figure 1 Another cross-sectional view of the mid-section line A-A';
[0037] Figure 9 This is another top view of a light-emitting substrate provided according to some embodiments;
[0038] Figure 10 For along Figure 1 Another cross-sectional view of the mid-section line A-A';
[0039] Figure 11This is a flowchart of a method for fabricating a light-emitting substrate according to some embodiments;
[0040] Figure 12 This is a process diagram illustrating the fabrication method of a light-emitting substrate according to some embodiments;
[0041] Figure 13 This is another flowchart of a method for fabricating a light-emitting substrate according to some embodiments;
[0042] Figure 14 This is a cross-sectional view of a backlight module provided according to some embodiments;
[0043] Figure 15 A cross-sectional view of a display device provided according to some embodiments;
[0044] Figure 16 This is a top view of a display device provided according to some embodiments. Detailed Implementation
[0045] The technical solutions in some embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.
[0046] Unless the context otherwise requires, throughout the specification and claims, the term "comprise" and its other forms, such as the third-person singular "comprises" and the present participle "comprising," are interpreted as open-ended and encompassing, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific example," or "some examples," etc., are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples.
[0047] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more.
[0048] In describing some embodiments, the terms "electrical connection" and "connection" and their derivatives may be used. For example, the term "electrical connection" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact with each other. The embodiments disclosed herein are not necessarily limited to the content of this document.
[0049] "At least one of A, B and C" has the same meaning as "at least one of A, B or C", both including the following combinations of A, B and C: only A, only B, only C, combinations of A and B, combinations of A and C, combinations of B and C, and combinations of A, B and C.
[0050] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.
[0051] The use of “configured as” in this article implies an open and inclusive language that does not exclude the applicability to or configuration of devices to perform additional tasks or steps.
[0052] As used herein, “about,” “approximately,” or “approximately” includes the stated value and the average value within an acceptable range of deviation from the given value, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the given quantity (i.e., the limitations of the measurement system).
[0053] As used herein, “parallel,” “perpendicular,” and “equal” include the described situation and situations that are similar to the described situation, within an acceptable range of deviation, which is determined by those skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “parallel” includes absolute parallelism and approximate parallelism, where an acceptable range of deviation for approximate parallelism may be, for example, within 5°; “perpendicular” includes absolute perpendicularity and approximate perpendicularity, where an acceptable range of deviation for approximate perpendicularity may also be, for example, within 5°; “equal” includes absolute equality and approximate equality, where an acceptable range of deviation for approximate equality may be, for example, a difference between the two equals being less than or equal to 5% of either one.
[0054] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on the other layer or substrate, or that there is an intermediate layer between the layer or element and the other layer or substrate.
[0055] This document describes exemplary embodiments with reference to cross-sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and regions is enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. For example, etched regions shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the regions of the device, nor are they intended to limit the scope of the exemplary embodiments.
[0056] With the development of display technology, micro-LEDs are increasingly favored as backlights. In products using micro-LEDs as backlights, after the die bonding process is completed, such as soldering the light-emitting device onto the substrate to obtain the light-emitting component, a reflective layer is attached to the light-emitting component, and the openings in the reflective layer are aligned with the light-emitting device, so that the light emitted by the light-emitting device can be effectively emitted from the openings.
[0057] In related technologies, after attaching a reflective layer to a light-emitting component, the light emission effect of at least some of the light-emitting devices on the light-emitting component decreases significantly. For example, the intensity and brightness of the light emitted by some light-emitting devices are reduced.
[0058] The inventors of this disclosure have discovered that after the reflective layer is attached to the light-emitting component, the openings on the reflective layer cannot be aligned with the light-emitting device. The reflective layer will cover part of the light-emitting device, causing the light emitted by the light-emitting device to be blocked by the reflective layer. As a result, the light emission effect of at least some of the light-emitting devices on the light-emitting component drops rapidly, affecting the display effect of the micro-LED as a backlight product and reducing the product yield.
[0059] To address the aforementioned technical problems, this disclosure provides a light-emitting substrate 100.
[0060] like Figure 1 As shown, the light-emitting substrate 100 includes a light-emitting component 10 and a reflective layer 20. The reflective layer 20 is disposed on the light-emitting side (the side from which light is emitted) of the light-emitting component 10.
[0061] like Figure 2 As shown, the light-emitting component 10 includes a substrate 1 and a plurality of light-emitting devices M disposed on the substrate 1. The plurality of light-emitting devices M are arranged in an array.
[0062] The light-emitting device M can be a micro LED, such as a Mini LED or a Micro LED.
[0063] For example, such as Figure 2 As shown, the light-emitting component 10 also includes a substrate 1, and a plurality of light-emitting devices M are disposed on the substrate 1, for example, the light-emitting devices M are soldered on the substrate 1.
[0064] For example, multiple light-emitting devices M are electrically connected to the substrate 1, such as multiple light-emitting devices M being electrically connected to signal lines on the substrate 1.
[0065] For example, substrate 1 may include any one of glass substrate, quartz substrate, sapphire substrate, ceramic substrate, etc.
[0066] For example, substrate 1 can be a semiconductor substrate. The semiconductor substrate is any one of the following: a single-crystal semiconductor substrate or a polycrystalline semiconductor substrate made of materials such as silicon or silicon carbide, a compound semiconductor substrate such as silicon-germanium, or an SOI (Silicon On Insulator) substrate.
[0067] For example, substrate 1 may also include an organic resin material such as epoxy resin, triazine, silicone resin or polyimide.
[0068] For example, substrate 1 can also be an FR4 type printed circuit board (PCB), or it can be a flexible PCB that is easily deformable.
[0069] For example, substrate 1 may also include a ceramic material such as silicon nitride, AlN or Al2O3, or a metal or metal compound, or any of the following: a metal core printed circuit board (MCPCB) or a metal copper clad laminate (MCCL).
[0070] For example, such as Figure 2 As shown, a pad P is provided on the substrate 1, and the pad P is an exposed conductive material. The light-emitting device M is fixed on the substrate 1 through the pad P and is electrically connected to the signal line on the substrate 1 through the pad P.
[0071] For example, the substrate 1 may be arranged with multiple device mounting areas, and the light-emitting device M is correspondingly disposed in the device mounting area. Each device mounting area may include at least one first connection pad and at least one second connection pad. The first connection pad and the second connection pad in the same device mounting area may be electrically connected to the electrode pins of the same light-emitting device M. For example, the first connection pad is electrically connected to the N-pin of the light-emitting device M, and the second connection pad is electrically connected to the P-pin of the light-emitting device M.
[0072] The substrate 1 may also include a circuit pattern electrically connected to at least one first connection pad and at least one second connection pad, so that multiple light-emitting devices M are connected in series and / or in parallel with each other.
[0073] For example, substrate 1 can be configured to block visible light (be non-transparent to visible light). When substrate 1 blocks visible light, ambient light can be suppressed from entering the light-emitting device M formed on substrate 1, thereby preventing ambient light from interfering with the normal light emission of the light-emitting device M. It should be noted that the embodiments disclosed herein are not limited to this, and substrate 1 may also be transparent to visible light.
[0074] like Figure 3 As shown, the reflective layer 20 has multiple openings K arranged in an array.
[0075] like Figure 1 As shown, multiple light-emitting devices M correspond one-to-one with multiple openings K, and the multiple light-emitting devices M are located within the multiple openings K. By placing the light-emitting devices M within the openings K, the reflective layer 20 can be prevented from blocking the light emitted by the light-emitting devices M, thus ensuring the light emission effect of the light-emitting substrate 100.
[0076] like Figure 4 As shown, the distance d between the center M1 of the light-emitting device M and the center K1 of the opening K where the light-emitting device M is located in the preset direction X is 0mm to 0.1mm. For example, the distance d can be 0mm, 0.001mm, 0.008mm, 0.01mm, 0.035mm, 0.0785mm or 0.1mm.
[0077] It should be noted that the aforementioned "center M1 of the light-emitting device M" can be the geometric center of the cross section of the light-emitting device M parallel to the substrate 1, and the aforementioned "center K1 of the opening K" can be the geometric center of the cross section of the opening K parallel to the substrate 1.
[0078] For example, before attaching the aforementioned reflective layer 20 to the light-emitting component 10, the distance between the centers of the two furthest openings K on the reflective layer 20 is set to be less than the distance between the centers of the two furthest light-emitting devices M on the light-emitting component 10 along the preset direction X. That is, before attaching the aforementioned reflective layer 20 to the light-emitting component 10, the size of the reflective layer 20 is pre-reduced, so that the amount of pre-reduction of the reflective layer 20 can offset the amount of extension that occurs during the attachment of the reflective layer 20 to the light-emitting component 10. As a result, after the reflective layer 20 is attached to the light-emitting component 10, the distance d between the center M1 of the light-emitting device M and the center K1 of the opening K where the light-emitting device M is located in the preset direction X can be controlled to be between 0 mm and 0.1 mm, which greatly improves the alignment accuracy of the opening K and the light-emitting device M.
[0079] It should be noted that the distance d between the center M1 of the light-emitting device M and the center K1 of the opening K where the light-emitting device M is located in the preset direction X is an ideal value after ignoring process errors, such as temperature, instrument precision and other interference factors. In the actual product manufacturing process, there may be slight process deviations, and the embodiments disclosed herein do not limit this.
[0080] The preset direction X is parallel to one side of the light-emitting component 10. For example, the preset direction X is parallel to one side of the substrate 1 of the light-emitting component 10.
[0081] For example, the preset direction X is the attachment direction of the reflective layer 20 when it is attached to the light-emitting component 10 during the fabrication process of the light-emitting substrate 100.
[0082] By controlling the distance d between the center M1 of the light-emitting device M and the center K1 of the opening K where the light-emitting device M is located in the preset direction X to be 0mm to 0.1mm, the alignment accuracy between the opening K of the reflective layer 20 and the light-emitting device M is improved, thereby effectively preventing the reflective layer 20 from covering the light-emitting device M and preventing the reflective layer 20 from blocking the transmission path of the light emitted by the light-emitting device M, thereby improving the light emission efficiency of the light-emitting device M and optimizing the light emission effect of the light-emitting substrate 100.
[0083] In some embodiments, such as Figure 1 and Figure 3 As shown, the reflective layer 20 has a first side 20a and a second side 20b, both of which are perpendicular to a preset direction X.
[0084] In the region between the first side 20a and the center line La parallel to the first side 20a of the reflective layer 20, the center M1 of the light-emitting device M (see reference) Figure 4 ), and the center K1 of the opening K where the light-emitting device M is located (see Figure 4 The spacing d in the preset direction X (see...) Figure 4 The spacing d can be 0mm to 0.05mm. For example, the spacing d can be 0mm, 0.001mm, 0.008mm, 0.01mm, 0.035mm, 0.0475mm or 0.05mm.
[0085] By controlling the distance d in the preset direction X between the center M1 of the light-emitting device M and the center K1 of the opening K where the light-emitting device M is located in the region between the first side 20a and the center line La of the reflective layer 20 parallel to the first side 20a, the alignment accuracy of the opening K of the reflective layer 20 and the light-emitting device M is further improved, the light emission efficiency of the light-emitting device M in the region between the first side 20a and the center line La of the reflective layer 20 parallel to the first side 20a is improved, and the light emission effect of the light-emitting substrate 100 is optimized.
[0086] In some embodiments, such as Figure 5 As shown, the light-emitting substrate 100 also includes a plurality of protective adhesives 30. At least a portion of the protective adhesives 30 are disposed within the opening K, and the protective adhesives 30 enclose the light-emitting device M located within the opening K.
[0087] For example, the protective adhesive 30 can be in the form of an adhesive. A dispensing machine is used to spray the adhesive-like protective adhesive 30 onto the light-emitting device M (i.e., dispensing), and the protective adhesive 30 is then cured to form a structure like... Figure 5 The hemispherical lens shown.
[0088] The protective adhesive 30 is configured to encapsulate the light-emitting device M to protect it from damage caused by moisture or external forces in the external environment. At the same time, the protective adhesive 30 acts as a hemispherical lens covering the light-emitting device M, which can improve the light-emitting effect of the light-emitting device M.
[0089] In an exemplary embodiment, the protective adhesive 30 fills and covers the opening K. This provides some protection for the opening K of the reflective sheet 20, preventing damage to the opening K during subsequent assembly.
[0090] In the plurality of protective adhesives 30, adjacent protective adhesives 30 are spaced apart.
[0091] For example, there is a gap between adjacent protective adhesives 30, which facilitates the formation of a hemispherical shape by the protective adhesives 30, thereby improving the light emission effect of the light-emitting substrate 100.
[0092] The inventors of this publication have discovered that in related technologies, after the protective adhesive covers the light-emitting device and cures, a large number of air bubbles are sealed inside the protective adhesive. In particular, there are large air bubbles at the positions where the sidewalls of the openings contact the light-emitting components, which seriously interfere with the light emission of the light-emitting device and reduce the light emission effect of the light-emitting substrate.
[0093] To address the aforementioned technical problems, in some embodiments, the opening K in the light-emitting substrate 100 provided in this disclosure is open. For example, see... Figure 6 Along the thickness direction of substrate 1, and from the end of opening K away from substrate 1 to the end of opening K close to substrate 1, the diameter of opening K gradually decreases.
[0094] By setting the opening K to be open, the space for air to escape can be increased, allowing the protective adhesive 30 to fully contact the sidewall K3 of the opening K and the light-emitting component 10 during the dispensing process. This avoids the problem of air residue in uncontacted areas due to insufficient contact between the protective adhesive 30 and the sidewall K3 of the opening K or the light-emitting component 10, which would cause the protective adhesive 30 to seal the residual air and form bubbles after curing. This can prevent bubbles from interfering with the light emission path of the light-emitting device M and effectively improve the light emission effect of the light-emitting substrate 100.
[0095] In an exemplary embodiment, such as Figure 6 As shown, the angle θ between the sidewall K3 of the opening K and the substrate 1 is an obtuse angle.
[0096] For example, the angle θ between the sidewall K3 of the opening K and the substrate 1 can be 120° to 150°. For example, the angle θ between the sidewall K3 of the opening K and the substrate 1 in the light-emitting component 10 is 130° to 140°. For example, the angle θ can be 120°, 125°, 137°, 142.5° or 150°.
[0097] In an exemplary embodiment, the sidewall K3 of the opening K can be arc-shaped, curving towards the opening K. The arc-shaped sidewall K3 is tangent to the substrate 1, and the central angle corresponding to the arc is an acute angle. The arc-shaped sidewall K3 makes the contact position between the sidewall K3 of the opening K and the light-emitting component 10 smoother, which is beneficial for the protective adhesive 30 to fill the opening K. This avoids the problem of insufficient contact between the protective adhesive 30 and the sidewall K3 of the opening K and the light-emitting component 10, resulting in air bubble residue, and further improves the light-emitting effect of the light-emitting substrate 100.
[0098] In some embodiments, the thixotropic index of the protective adhesive 30 is 4.9 to 5.9. By reducing the thixotropic index of the protective adhesive 30, the curing speed of the protective adhesive 30 after dispensing is slowed down, thereby ensuring that the adhesive-like protective adhesive 30 can fully fill each position of the opening K, allowing the air in the opening K to dissipate in a timely manner. This effectively solves the problem of air bubbles being trapped after the protective adhesive 30 cures, thereby preventing air bubbles from interfering with the light emission path of the light-emitting device M and effectively improving the light emission effect of the light-emitting substrate 100.
[0099] In related technologies, such as Figure 7 As shown, after the protective adhesive 30' is cured, there is a problem that the reflective sheet 20' shrinks and the light-emitting device M' falls off. That is, the light-emitting device M' is displaced relative to the pad P', causing the light-emitting device M' to fall off the substrate 1'.
[0100] To address the aforementioned technical problems, in some embodiments, the protective adhesive 30 in the light-emitting substrate 100 provided in this disclosure comprises a UV-curable adhesive. This protective adhesive 30 can be cured by UV irradiation after dispensing.
[0101] By setting the material of the protective adhesive 30 to be a UV-curable adhesive, the high-temperature baking method is avoided during the curing process of the protective adhesive 30. This avoids the light-emitting substrate 100 being in a high-temperature environment and prevents the reflector 20 from shrinking significantly from its periphery towards its center in a high-temperature environment. This also prevents the shrinking reflector 20 from causing the protective adhesive 30 on it to shift, which could lead to the light-emitting device M covered by the protective adhesive 30 shifting and falling off. This improves the yield of the light-emitting substrate 100.
[0102] In some embodiments, the curing temperature of the protective adhesive 30 is lower than the glass transition temperature of the reflective layer 20.
[0103] It should be noted that the aforementioned "glass transition temperature" refers to the critical temperature at which the reflective layer 20 transitions from a highly elastic state to a glassy state, or vice versa. Below the glass transition temperature, the reflective layer 20 is made of glass and has a certain degree of brittleness; above the glass transition temperature, the reflective layer 20 is made of flexible material and has high elasticity.
[0104] As the temperature increases, during the process of the reflective layer 20 changing from a glassy state to a highly elastic state, the molecular chains of the reflective layer 20 become more mobile at high temperatures, and the internal stress of the reflective layer 20 causes the reflective layer 20 to contract from the periphery towards the center.
[0105] By setting the curing temperature of the protective adhesive 30 to be lower than the glass transition temperature of the reflective layer 20, the transition of the reflective layer 20 from the glassy state to the elastic state can be avoided to a certain extent, reducing the degree of inward shrinkage of the reflective layer 20, thereby reducing the displacement of the protective adhesive 30, preventing the protective adhesive 30 from causing the light-emitting device M to displace and fall off, and improving the yield of the light-emitting substrate 100.
[0106] For example, the material of the reflective layer 20 may include polyethylene terephthalate, which has a glass transition temperature of approximately 100°C to 120°C.
[0107] For example, the curing temperature of the protective adhesive 30 is set to approximately 80°C to 100°C. This allows the ambient temperature of the reflective sheet 20 to be controlled to be lower than the glass transition temperature of the reflective layer 20, thereby reducing the degree of shrinkage of the reflective layer 20.
[0108] In an exemplary embodiment, the material of the protective adhesive 30 includes a platinum-based complexing catalyst, such as a methylvinylsiloxane coordinated platinum catalyst, and / or a platinum-divinyltetramethyldisiloxane catalyst.
[0109] For example, the material of the protective adhesive 30 may include silicone resin. Silicone resin is a polysiloxane polymer with a highly cross-linked structure. Its curing mechanism is that, under heating conditions, the silicon in the silicone resin material undergoes an addition reaction with the hydrogen in the cross-linking agent, cross-linking to form a three-dimensional network structure, thus completing the curing process.
[0110] When the curing conditions of the protective adhesive 30 are 150℃ / 1h, the reflective layer 20 will shrink significantly, which may cause the light-emitting device M to fall off. However, when the curing temperature of the protective adhesive 30 is reduced to below the glass transition temperature of the reflective layer 20, the curing time is longer. For example, it requires 6 hours of curing at 100℃, which seriously affects the production efficiency of the product.
[0111] By adding platinum-based complexing catalysts, such as methylvinylsiloxane-coordinated platinum catalysts and / or platinum-divinyltetramethyldisiloxane catalysts, to the protective adhesive 30, the hydrosilylation reaction can be accelerated, thereby reducing the curing time of the protective adhesive 30, ensuring production efficiency, and at the same time keeping the curing temperature of the protective adhesive 30 below the glass transition temperature of the reflective layer 20, avoiding the problem of the light-emitting device M falling off due to the shrinkage of the reflective layer 20, and improving the yield of the light-emitting substrate 100.
[0112] In some embodiments, such as Figure 8 As shown, the light-emitting substrate 100 also includes an adhesive layer 40.
[0113] like Figure 8 As shown, the adhesive layer 40 is disposed on the side of the reflective layer 20 close to the light-emitting component 10, and the adhesive layer 40 is disposed away from the opening K.
[0114] like Figure 9 As shown, the side boundary 40a of the adhesive layer 40 extends beyond the side boundary 20a of the reflective layer 20.
[0115] The adhesive layer 40 is configured to bond the reflective layer 20 to the light-emitting component 10, for example, to the substrate 1 of the light-emitting component 10.
[0116] In some embodiments, such as Figure 9 As shown, the extended portion of the adhesive layer 40 includes a first sub-region 41 and a second sub-region 42 that are sequentially located away from the center 40b of the adhesive layer, with the second sub-region 42 surrounding the first sub-region 41.
[0117] In some embodiments, such as Figure 9As shown, the width d3 of the first sub-region 41 is 0.002mm to 0.005mm. For example, the width d3 of the first sub-region 41 can be 0.002mm, 0.0025mm, 0.00348mm, 0.004mm or 0.005mm.
[0118] The width d4 of the second sub-region 42 is 0.5×A×L3, where A is the shrinkage rate of the reflective layer 20 and L3 is the length of the reflective layer 20 along the preset direction X.
[0119] It should be noted that the shrinkage rate A of the reflective layer 20 is the shrinkage rate of the reflective layer 20 under high temperature conditions (e.g., at the glass transition temperature of the reflective layer 20). For example, the shrinkage rate of the reflective layer 20 under baking conditions of 150°C / 1h is approximately 0.07% to 0.08%.
[0120] In some embodiments, such as Figure 10 As shown, the light-emitting substrate 100 also includes a white oil layer 50.
[0121] like Figure 10 As shown, the white oil layer 50 is disposed between the substrate 1 and the reflective layer 20. The white oil layer 50 has multiple openings N, through which the light-emitting device M is exposed, thus preventing the white oil layer 50 from blocking the light emitted by the light-emitting device M.
[0122] That is, the white oil layer 50 is disposed between the light-emitting component 10 and the reflective layer 20, and the white oil layer 50 is disposed away from the light-emitting device M.
[0123] For example, such as Figure 10 As shown, the white oil layer 50 is disposed between the substrate 1 and the adhesive layer 40 of the light-emitting component 10.
[0124] For example, the white oil layer 50 may include resin (e.g., epoxy resin, polytetrafluoroethylene resin), titanium dioxide (chemical formula TiO2), and organic solvent (e.g., dipropylene glycol methyl ether).
[0125] This disclosure also provides a method for preparing a light-emitting substrate 100. For example... Figure 11 As shown, the preparation method includes:
[0126] S1: Provides light-emitting components.
[0127] like Figure 12 As shown, the light-emitting component 10 includes a substrate 1 and a plurality of light-emitting devices M arranged in an array on the substrate 1.
[0128] For example, such as Figure 12 As shown, the light-emitting component 10 also includes a substrate 1, and the light-emitting device M is soldered onto the substrate 1.
[0129] like Figure 12As shown, in step S1, the distance between the centers of the two light-emitting devices M that are furthest apart on the light-emitting component 10 along the preset direction X is the first dimension d1.
[0130] S2: Provides a reflective layer.
[0131] like Figure 12 As shown, the reflective layer 20 has multiple openings K arranged in an array, and the number of openings K is equal to the number of light-emitting devices M.
[0132] like Figure 12 As shown, in step S2, the distance between the centers of the two farthest openings K on the reflective layer 20 along the preset direction X is the second dimension d2.
[0133] like Figure 12 As shown, the second dimension d2 is smaller than the first dimension d1.
[0134] For example, such as Figure 12 As shown, an adhesive layer 40 is provided on one side of the reflective sheet 20, and the adhesive layer 40 is configured to fix the reflective sheet 20 to the light-emitting component 10.
[0135] S3: Attach the reflective layer to the light-emitting component along the preset direction.
[0136] like Figure 12 As shown, multiple light-emitting devices M are respectively located in multiple openings K.
[0137] For example, the preset direction X is the attachment direction of the reflective layer 20, and the preset direction X may be parallel to one side of the light-emitting component 10.
[0138] For example, such as Figure 12 As shown, after step S3, along the preset direction X, the distance between the centers of the two farthest light-emitting devices M on the light-emitting component 10 is approximately equal to the distance between the centers of the two farthest openings K on the reflective layer 20.
[0139] By setting the second dimension d2 to be smaller than the first dimension d1, that is, before the reflective layer 20 is attached to the light-emitting component 10, the dimension of the reflective layer 20 along the preset direction X is reduced in advance, so that the amount of pre-reduction can offset the amount of stretching of the reflective layer 20 during the attachment process to the light-emitting component 10. This can avoid the problem that the reflective layer 20 will stretch and cover the light-emitting device M during the attachment process, thus blocking the transmission path of the light emitted by the light-emitting device M, thereby improving the light emission efficiency of the light-emitting device M and optimizing the light emission effect of the light-emitting substrate 100.
[0140] For example, the light-emitting substrate 100 prepared by the preparation method provided in the present disclosure can control the distance d between the center M1 of the light-emitting device M and the center K1 of the opening K where the light-emitting device M is located in the preset direction X to be within 0 mm to 0.1 mm, which greatly improves the alignment accuracy between the opening K of the reflective layer 20 and the light-emitting device M.
[0141] For example, such as Figure 12 As shown, the light-emitting substrate 100 also includes a release film 60 and a protective film 70. The release film 60 and the protective film 70 are respectively disposed on both sides of the reflective layer 20 before it is attached. The release film 60 and the protective film 70 are configured to protect the reflective layer 20 from external damage during the transfer process. During the attachment process of the reflective layer 20, the release film 60 and the protective film 70 are removed.
[0142] For example, such as Figure 12 As shown, in step S2, a release film 60 and a protective film 70 are respectively provided on both sides of the reflective layer 20. Before step S3, the release film 60 is removed to expose the adhesive layer 40 coated on one side of the reflective layer 20, facilitating the attachment of the reflective layer 20 to the light-emitting component 10. After step S3, the protective film 70 is removed to expose the opening K, facilitating the application of the protective adhesive 30.
[0143] In some embodiments, the difference ΔL between the first dimension d1 and the second dimension d2 is S × L. Where S is the elongation coefficient of the reflective layer 20, and L is the value of the second dimension d2.
[0144] It should be noted that the reflective layer 20 will stretch during the application process. The aforementioned "stretch factor" refers to the amount of stretch per unit length of the reflective layer 20 along the application direction (e.g., a preset direction X). For example, if the length of the reflective layer 20 along the application direction is 802.2 mm before application and 802.5 mm after application, the stretch factor of the reflective layer 20 is...
[0145] For example, the elongation coefficient S of the reflective layer 20 is related to the material of the reflective layer 20 and the preparation conditions of the reflective layer 20, such as temperature and duration. For example, the elongation coefficient S of the reflective layer 20 is different for different materials.
[0146] By setting a calculation method for the difference ΔL between the first dimension d1 and the second dimension d2, the aforementioned preparation method can be applied to any light-emitting substrate 100 with different sizes and different numbers of light-emitting devices M. This allows the reflective layer 20 in any light-emitting substrate 100 to be attached to the light-emitting component 10, achieving high-precision alignment between the opening K and the light-emitting device M, thereby improving the light extraction efficiency of the light-emitting device M and optimizing the light-emitting effect of the light-emitting substrate 100.
[0147] In some embodiments, see Figure 1 The light-emitting component 10 includes multiple rows of light-emitting devices M, and each row of light-emitting devices M includes multiple light-emitting devices M arranged sequentially along a preset direction X.
[0148] Before the reflective layer 20 is attached, the distance between the centers of two adjacent openings K in the reflective layer 20 along the preset direction X. Where L2 is the distance between the centers of two adjacent light-emitting devices M in a row of light-emitting devices M, and n is the number of light-emitting devices M included in a row of light-emitting devices M.
[0149] By setting the distance between the centers of two adjacent openings K in the reflective layer 20 along a preset direction X before the reflective layer 20 is attached, the distance between the centers of two adjacent openings K in the reflective layer 20 is... This allows the preparation method provided in the aforementioned embodiments to be applied to light-emitting substrates 100 using different types of reflective layers 20, thereby improving the alignment accuracy between the opening K and the light-emitting device M and optimizing the light-emitting effect of the light-emitting substrate 100.
[0150] In some embodiments, such as Figure 13 As shown, after step S3, the aforementioned preparation method further includes:
[0151] S4: Pre-bake the light-emitting components with the reflective layer attached.
[0152] By pre-baking, the reflective layer 20 shrinks before the protective adhesive 30 is filled into the opening K, which can avoid the problem of the reflective layer 20 causing the protective adhesive 30 to shift due to shrinkage, ultimately leading to the detachment of the light-emitting device M.
[0153] For example, the pre-baking temperature is higher than the glass transition temperature of the reflective layer 20. That is, the reflective layer 20 may undergo a glassy to elastic transition before the protective adhesive 30 is filled into the opening K, thereby allowing the reflective layer 20 to shrink sufficiently and reducing the degree of shrinkage after the protective adhesive 30 is filled in.
[0154] For example, the pre-baking temperature is approximately 140°C to 160°C. For instance, the temperature could be 140°C, 143°C, 145.5°C, 150°C, 157.9°C, or 160°C. The pre-baking time is approximately 10 minutes to 30 minutes. For instance, the pre-baking time could be 10 minutes, 11 minutes, 15.6 minutes, 20 minutes, 28.75 minutes, or 30 minutes.
[0155] S5: Apply protective adhesive inside and above the openings in the reflective layer.
[0156] For example, in this embodiment, the material of the protective adhesive 30 can be silicone resin.
[0157] S6: Curing of the protective adhesive.
[0158] For example, in this embodiment, the protective colloid is cured by high-temperature baking.
[0159] For example, the curing temperature is approximately 140°C to 160°C. For instance, the curing temperature could be 140°C, 143°C, 145.5°C, 150°C, 157.95°C, or 160°C. The curing time is approximately 50 minutes to 70 minutes. For instance, the curing time could be 50 minutes, 51 minutes, 55.6 minutes, 60 minutes, 68.75 minutes, or 70 minutes.
[0160] For example, after pre-baking, in step S6, the shrinkage of the reflective layer 20 can be controlled within 0.005 mm.
[0161] By pre-baking the reflective sheet 20, the reflective layer 20 shrinks before the protective adhesive 30 is filled into the opening K, achieving a full transition of the reflective layer 20 from a glassy state to a highly elastic state. This allows for a smaller shrinkage of the reflective layer 20 during the curing process of the protective adhesive 30 after it is filled into the opening K, thus avoiding significant displacement of the protective adhesive 30. This prevents the light-emitting device M from detaching due to the displacement of the protective adhesive 30, thereby improving the yield of the light-emitting substrate 100.
[0162] In some embodiments, after step S3, step S4 is removed, and steps S5 and S6 are performed directly; that is, after step S3, the aforementioned preparation method further includes:
[0163] S5: Apply protective adhesive inside and above the openings in the reflective layer.
[0164] Exemplarily, in this embodiment, the material of the protective colloid 30 may include a silicone resin and a platinum-based complexing catalyst. For example, the material of the protective colloid 30 includes a silicone resin and a methylvinylsiloxane-coordinated platinum catalyst. And / or, the material of the protective colloid 30 includes a silicone resin and a platinum-divinyltetramethyldisiloxane catalyst.
[0165] S6: Curing of the protective adhesive.
[0166] For example, in this embodiment, the protective colloid is cured by high-temperature baking.
[0167] For example, the curing temperature of the protective adhesive 30 is lower than the glass transition temperature of the reflective layer 20.
[0168] For example, the curing temperature is approximately 80°C to 100°C, such as 80°C, 83.358°C, 85.5°C, 90°C, 97.95°C, or 100°C. The curing time is approximately 50 min to 70 min, such as 50 min, 51 min, 55.6 min, 60 min, 68.75 min, or 70 min.
[0169] By setting the material of the protective adhesive 30 to include a platinum-based complex catalyst, the curing temperature of the protective adhesive 30 can be controlled below the glass transition temperature of the reflective layer 20 without extending the curing time of the protective adhesive 30 and avoiding reducing production efficiency. This can prevent the reflective layer 20 from shrinking, solve the problem of the light-emitting device M falling off due to the displacement of the protective adhesive 30 caused by the shrinkage of the reflective layer 20, and improve the yield of the light-emitting substrate 100.
[0170] In some embodiments, after step S3, step S4 is removed, and steps S5 and S6 are performed directly; that is, after step S3, the aforementioned preparation method further includes:
[0171] S5: Apply protective adhesive inside and above the openings in the reflective layer.
[0172] For example, in this embodiment, the material of the protective adhesive 30 may include a UV-curable adhesive.
[0173] S6: Curing of the protective adhesive.
[0174] For example, in this embodiment, step S6 includes curing the protective adhesive 30 using an ultraviolet light irradiation method.
[0175] By setting the material of the protective adhesive 30 to be a UV-curable adhesive, the curing process of the protective adhesive 30 does not require high-temperature baking, thus avoiding the reflective layer 20 being in a high-temperature environment and preventing the reflective layer 20 from shrinking. This solves the problem of the light-emitting device M falling off due to the displacement of the protective adhesive 30 caused by the shrinkage of the reflective layer 20, thereby improving the yield of the light-emitting substrate 100.
[0176] In some embodiments, such as Figure 14 As shown, this disclosure also provides a backlight module 300, including an optical film 200 and a light-emitting substrate 100 of any of the foregoing embodiments.
[0177] For example, the light-emitting substrate 100 has a display side and a non-display side. The display side is the side from which light is emitted from the light-emitting substrate 100, and the non-display side is the side opposite to the display side.
[0178] An optical film 200 is disposed on the light-emitting side of the light-emitting substrate 100.
[0179] For example, the optical film 200 can be multi-layered. The optical film 200 includes a light-diffusing film and a light-enhancing film, etc., which can adjust the intensity, uniformity, etc. of the light emitted by the light-emitting device M, thereby improving the display effect of the display device 1000.
[0180] In some embodiments, such as Figure 15 and Figure 16 As shown, this disclosure also provides a display device 1000.
[0181] The display device 1000 includes a display panel 400 and a backlight module 300 as described in any of the preceding embodiments.
[0182] The display panel 400 can be an LCD display panel.
[0183] For example, the display panel 400 has a display side and a non-display side. The display side is the side from which light is emitted from the display panel 400 to display an image, and the non-display side is the side opposite to the display side.
[0184] The backlight module 300 is located on the non-display side of the display panel 400.
[0185] The backlight module 300 is located on the non-display side of the display panel 400 and can provide a backlight for the display panel 400 to achieve luminous display.
[0186] The beneficial effects that the display device 1000 in this embodiment can achieve are the same as those that the backlight module 100 can achieve, and will not be repeated here.
[0187] The display device 1000 can be any device that displays images, whether moving (e.g., video) or fixed (e.g., still images), and whether it contains text or images. More specifically, the intended embodiments can be implemented in or associated with a variety of electronic devices, such as (but not limited to) mobile phones, wireless devices, personal digital assistants (PDAs), virtual reality (VR) displays, handheld or portable computers, Global Positioning System (GPS) receivers / navigators, cameras, MP4 video players, camcorders, game consoles, watches, clocks, calculators, television monitors, flat panel displays, computer monitors, automotive displays (e.g., odometer displays, etc.), navigators, cockpit controllers and / or displays, displays of camera views (e.g., displays of rearview cameras in vehicles), electronic photographs, electronic billboards or signs, projectors, architectural structures, packaging and aesthetic structures (e.g., displays of images of a piece of jewelry), etc.
[0188] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.
Claims
1. A method for preparing a light-emitting substrate, characterized in that, include: A light-emitting component is provided, the light-emitting component including a substrate and a plurality of light-emitting devices disposed on the substrate in an array; Along a preset direction, the distance between the centers of the two farthest light-emitting devices on the light-emitting component is a first dimension; A reflective layer is provided, the reflective layer having a plurality of openings arranged in an array, the number of the plurality of openings being equal to the number of the plurality of light-emitting devices; along the preset direction, the distance between the centers of the two openings that are furthest apart on the reflective layer is a second dimension; The second dimension is smaller than the first dimension; The reflective layer is attached to the light-emitting component along the preset direction, so that the plurality of light-emitting devices are respectively located in the plurality of openings; The light-emitting component with the reflective layer attached is pre-baked; A protective adhesive is applied inside and above the opening. The protective adhesive is then cured.
2. The preparation method according to claim 1, characterized in that, The difference between the first dimension and the second dimension Where S is the elongation coefficient of the reflective layer, and L is the second dimension.
3. The preparation method according to claim 2, characterized in that, The light-emitting component includes multiple rows of light-emitting devices, and each row of light-emitting devices includes multiple light-emitting devices arranged sequentially along the preset direction; Before the reflective layer is attached, the distance between the centers of two adjacent openings in the reflective layer along the preset direction. ; Where L2 is the distance between the centers of two adjacent light-emitting devices in a row, and n is the number of light-emitting devices included in a row.
4. The preparation method according to claim 1, characterized in that, The pre-baking temperature range is 140℃~160℃, and the baking time range is 10min~30min; The curing temperature range is 140℃~160℃, and the curing time range is 50min~70min.
5. A backlight module, characterized in that, include: A light-emitting substrate, wherein the light-emitting substrate is prepared by any one of claims 1 to 4; An optical film is disposed on the light-emitting side of the light-emitting substrate.
6. A display device, characterized in that, include: Display panel; The backlight module as described in claim 5 is disposed on the non-light-emitting side of the display panel.