LED devices and displays

Abstract

A light-emitting diode (LED) device and a display are disclosed. The LED device includes an LED chip, a first lens, and a second lens. The first lens is positioned above the LED chip and configured to increase light extraction efficiency. The first lens contains a first amount of titanium dioxide. The second lens is positioned above the first lens and configured to modify the light pattern. The second lens contains a second amount of titanium dioxide, wherein the second amount of titanium dioxide is greater than the first amount of titanium dioxide. The LED device disclosed herein achieves better light extraction efficiency and light mixing effect.

Description

Technical Field

[0001] This disclosure pertains to the packaging structure of a light-emitting diode (LED) device. Background Technology

[0002] A light-emitting diode (LED) is a solid-state semiconductor device that converts electrical energy into light energy. LED packaging refers to encapsulating the LED chip in a specific structure that allows light to pass through while protecting the chip.

[0003] Please refer to Figure 1A The diagram illustrates the package structure of a known light-emitting diode (LED) device 10. The LED device 10 is a flip-chip-level package. The LED chip 20 is disposed on top of a printed circuit board (PCB) 40 and electrically connected to the circuitry of the PCB 40 via an anode pad 22 and a negative pad 24. The LED chip 20 is externally encapsulated with encapsulant 30 to protect it. The encapsulant 30 is typically a silicon-based resin with a refractive index of approximately 1.4 to 1.51.

[0004] The encapsulant 30 of the known light-emitting diode device 10 is often made of non-epoxy resin. When exposed to ultraviolet light emitted by the light-emitting diode chip 20 for a long time, the encapsulant 30 will gradually yellow, thus affecting the light emission efficiency of the light-emitting diode device 10.

[0005] In addition, please see Figure 1B and Figure 1C They are respectively Figure 1A The ray tracing plot and candela plot / light distribution curve of the light-emitting diode device 10 are shown. The emitted beam of the high-proportion light-emitting diode chip 20 is emitted from directly above the light-emitting diode device, and the light pattern shown in the candela plot is elliptical. Therefore, the light field intensity distribution of the known light-emitting diode device 10 is excessively concentrated in the center, resulting in poor uniformity and emission angle. Since the light-emitting diode device is a point light source, the known light-emitting diode device often requires additional design to diffuse the emitted light more uniformly, for example, by adding a secondary optical lens to the light-emitting diode device to obtain an ideal light pattern.

[0006] For example, light-emitting diode (LED) devices can be used in displays. As displays become increasingly widespread, they can now integrate camera, communication, and display functions, and their resolution has improved from 4K to 8K. Miniature LED backlights not only allow for more detailed local dimming zones but also achieve high dynamic range (HDR) for high contrast. Current direct-lit displays (such as LCD TVs, laptops, and tablets) often use a secondary optical lens above the LED device. This secondary lens redistributes the light emitted by the LED, adjusting the energy to meet the field pattern design requirements of displays with a cavity height of 10 mm or more.

[0007] However, for ultra-thin displays (with an optical cavity height of less than 10 mm), direct-lit backlights cannot be designed in this way. Traditional secondary optical lenses require a certain cavity height, but ultra-thin displays with relatively small internal space cannot provide the light refraction distance and angle needed for secondary optical lenses to change the light field pattern, thus easily causing defects such as uneven light mixing. Summary of the Invention

[0008] Some embodiments of this disclosure provide a light-emitting diode (LED) device, including: an LED chip, a first lens, and a second lens. The first lens is positioned above the LED chip and configured to increase light extraction efficiency; the first lens contains a first amount of titanium dioxide. The second lens is positioned above the first lens and configured to change the light pattern; the second lens contains a second amount of titanium dioxide. The second amount of titanium dioxide is more than the first amount of titanium dioxide.

[0009] In some embodiments, the materials of the first lens and the second lens comprise silicon-based epoxy resin.

[0010] In some embodiments, the first content of titanium dioxide in the first lens is greater than 0.01 weight percentage of the first lens.

[0011] In some embodiments, the first content of titanium dioxide in the first lens is less than 0.5% by weight of the first lens.

[0012] In some embodiments, the second content of titanium dioxide in the second lens is greater than 0.5 weight percentage of the second lens.

[0013] In some embodiments, the second content of titanium dioxide in the second lens is less than 2 weight percentages of the second lens.

[0014] In some embodiments, the particle size of the titanium dioxide in the first lens and the titanium dioxide in the second lens is less than 1 / 10 of the wavelength of the emitted light from the LED chip.

[0015] In some embodiments, the titanium dioxide particles of the first lens and the titanium dioxide particles of the second lens have a particle size of less than 40 nanometers.

[0016] In some implementations, the light-emitting diode chip is a blue light chip.

[0017] In some implementations, the light-emitting diode device is a wafer-level package structure.

[0018] Some embodiments of this disclosure provide a light-emitting diode (LED) device comprising: an LED chip, a first lens, and a second lens. The first lens is located above the LED chip and comprises less than 0.5 weight percent of titanium dioxide. The second lens is located above the first lens and comprises more than 0.5 weight percent of titanium dioxide.

[0019] In some embodiments, the titanium dioxide of the first lens is dispersed within the first lens.

[0020] In some embodiments, the titanium dioxide of the second lens is dispersed within the second lens.

[0021] In some embodiments, the second lens comprises a resin material, and the titanium dioxide of the second lens forms a thin film that covers the resin material of the second lens.

[0022] In some implementations, the first lens is in direct contact with the light-emitting diode chip.

[0023] In some implementations, the second lens directly contacts the first lens.

[0024] In some implementations, the first lens is configured to increase the refraction of light.

[0025] In some embodiments, the refractive index of the second lens is less than that of the first lens.

[0026] In some embodiments, the light transmittance of the second lens is less than that of the first lens.

[0027] Some embodiments of this disclosure provide a display comprising any of the embodiments of the light-emitting diode device described above or below, and the display having a light cavity with a height of less than 10 mm.

[0028] In some implementations, the light-emitting diode device serves as a direct-lit backlight for the display. Attached Figure Description

[0029] The various aspects of this disclosure can be best understood by reading the following detailed description in conjunction with the accompanying drawings. It is worth noting that, in accordance with common industry practice, the features are not drawn to scale. In fact, the dimensions of the features may be arbitrarily increased or decreased for clarity of illustration and discussion.

[0030] Figure 1A Draw a cross-sectional view of the structure of a known wafer-level packaged light-emitting diode device;

[0031] Figure 1B Plot the ray tracing diagram of a known chip-scale packaged light-emitting diode device;

[0032] Figure 1C Plot the candela plots / light distribution curves of known wafer-level packaged light-emitting diode devices;

[0033] Figure 2 The relationship between different concentrations of titanium dioxide and light transmittance is illustrated.

[0034] Figure 3 The relationship between different concentrations of titanium dioxide and the refractive index of light is illustrated.

[0035] Figure 4A A cross-sectional view illustrating the structure of a light-emitting diode device according to some embodiments of this disclosure;

[0036] Figure 4B A ray tracing diagram of a light-emitting diode device according to some embodiments of this disclosure is shown;

[0037] Figure 4C Candela plots / light distribution curves of light-emitting diode devices according to some embodiments of this disclosure are shown;

[0038] Figure 5A and Figure 5B A cross-sectional view of a light-emitting diode device according to some embodiments of this disclosure is shown;

[0039] Figure 6A and Figure 6B A cross-sectional view of a light-emitting diode package structure according to some embodiments of this disclosure is shown;

[0040] Figure 7 An exploded view of a backlight module according to some embodiments of this disclosure is shown.

[0041] [Symbol Explanation]

[0042] 10: Light Emitting Diode Device

[0043] 20: Light Emitting Diode Chip

[0044] 22: Positive electrode pad

[0045] 24: Negative electrode pad

[0046] 40: Printed Circuit Board

[0047] 100: Light Emitting Diode Device

[0048] 110:Substrate

[0049] 120: Light Emitting Diode Structure

[0050] 132: First solder pad

[0051] 134: Second solder pad

[0052] 140: Light Emitting Diode Chip

[0053] 150: First lens

[0054] 160: Second lens

[0055] 200: Light Emitting Diode Device

[0056] 210:Substrate

[0057] 220: Light Emitting Diode Package Structure

[0058] 232: First solder pad

[0059] 234: Second solder pad

[0060] 240: Light Emitting Diode Chip

[0061] 242: Top surface

[0062] 244: Side View

[0063] 250: First lens

[0064] 260: Second lens

[0065] 300: Light Emitting Diode Device

[0066] 310:Substrate

[0067] 320: Light Emitting Diode Package Structure

[0068] 332: First solder pad

[0069] 334: Second solder pad

[0070] 340: Light Emitting Diode Chip

[0071] 350: First lens

[0072] 360: Second Lens

[0073] 420: Light Emitting Diode Package Structure

[0074] 422: Bracket

[0075] 424: Guide hole

[0076] 426: First extended solder pad

[0077] 428: Second extension pad

[0078] 432: First solder pad

[0079] 434: Second solder pad

[0080] 440: Light Emitting Diode Chip

[0081] 450: First lens

[0082] 460: Second lens

[0083] 520: Light Emitting Diode Package Structure

[0084] 540: Light Emitting Diode Chip

[0085] 542: Top surface

[0086] 544: Side View

[0087] 550: First lens

[0088] 560: Second Lens

[0089] 570: Protective layer

[0090] 700: Backlight Module

[0091] 710: Backplate

[0092] 720: LED strip

[0093] 722: Circuit Board

[0094] 724: Light Emitting Diode Components

[0095] 730: Backlight cavity

[0096] 732: Opening

[0097] 740: Optical film

[0098] D1: First dimension

[0099] D2: Second size

[0100] T1: First thickness

[0101] T2: Second thickness

[0102] T3: Third Thickness

[0103] T4: Fourth Thickness Detailed Implementation

[0104] The following disclosure provides different implementations or embodiments to achieve different features of the provided object. Specific embodiments of components and configurations are described below to simplify this disclosure. Of course, these are merely embodiments and are not intended to limit this disclosure. For example, in the following description, forming a first feature above a second feature may include implementations where the first and second features are formed in direct contact, and may also include implementations where additional features are disposed between the first and second features, thus the first and second features are not in direct contact. Furthermore, numbers and / or letters may be repeatedly designated in various embodiments. Such repetition is not intended to indicate a relationship between the various implementations and / or configurations discussed.

[0105] Furthermore, to facilitate the description of the relationship between one element or feature and another, as illustrated in the accompanying drawings, spatially relative terms such as "below," "below," "lower than," "above," "above," "above," and similar terms may be used herein. In addition to the directions illustrated in the accompanying drawings, the spatially relative terms are intended to cover different orientations of the device in use or operation. The device may have other orientations (rotation 90 degrees or other orientations), and the spatially relative terms used herein may be interpreted accordingly.

[0106] In view of the problems of unsatisfactory light pattern or uneven light mixing in known light-emitting diode devices, some embodiments of the present disclosure provide a solution by setting two lenses above the light-emitting diode chip in the structure of the light-emitting diode chip device. These two lenses contain different amounts of titanium dioxide, thereby changing the light pattern of the light-emitting diode device and increasing the light extraction efficiency.

[0107] Please refer to Figure 2 The graph illustrates the relationship between different concentrations of titanium dioxide and light transmittance in silicon-based epoxy resins, with the tested titanium dioxide particles having a particle size of less than 40 nanometers. Figure 2 In the experiment shown, the effects of different proportions of titanium dioxide (TiO2) of 0.01 wt%, 0.1 wt%, 0.5 wt%, and 1 wt% on the transmittance of light of different wavelengths were tested.

[0108] Figure 2 The dashed line represents a wavelength of 450 nanometers, which is the typical wavelength used in blue LED chips. Figure 2In the ultraviolet light wavelength range, such as light with wavelengths less than 400 nanometers, the addition of titanium dioxide significantly reduces transmittance. Therefore, placing a silicon-based epoxy resin layer containing titanium dioxide above the LED chip can filter out some of the ultraviolet light output, increasing the purity of the blue light emitted by the LED device. The silicon-based epoxy resin layer has better resistance to ultraviolet light, thus it is less prone to yellowing like the commonly used encapsulating adhesive 30 in known technologies. The added titanium dioxide also reduces ultraviolet transmittance, enhancing the ultraviolet absorption effect.

[0109] Figure 2 The results showed that when 1 wt% titanium dioxide was added to the silicone epoxy resin, the transmittance of light at a wavelength of 450 nm was approximately 20%. When 0.5 wt% titanium dioxide was added, the transmittance of light at a wavelength of 450 nm was approximately 65%. When 0.01 to 0.1 wt% titanium dioxide was added, the transmittance of light at a wavelength of 450 nm was between approximately 75% and approximately 85%. Therefore, when less than 0.1 wt% titanium dioxide was added to the silicone epoxy resin, the effect of titanium dioxide on the transmittance of light became smaller. Figure 2 The experimental results shown demonstrate that by setting a silicon-based epoxy resin layer with titanium dioxide on the light-emitting diode chip, the content of titanium dioxide can be adjusted to achieve the desired light transmittance or light pattern.

[0110] Please refer to Figure 3 The graph illustrates the relationship between the refractive index of different concentrations of titanium dioxide in silicon-based epoxy resin and blue light with wavelengths of 445 to 450 nanometers. The particle size of the tested titanium dioxide particles is less than 40 nanometers. Figure 3 The results show that when no titanium dioxide is added to the silicon-based epoxy resin, the refractive index of light in the silicon-based epoxy resin is approximately 1.5. When the titanium dioxide concentration is gradually increased to 0.1 wt%, the refractive index of light in the silicon-based epoxy resin reaches its highest point, approximately 1.61 to 1.62. Afterward, as the titanium dioxide concentration increases further, the refractive index of light in the silicon-based epoxy resin actually decreases; for example, when the titanium dioxide concentration is gradually increased to 0.5 wt%, the refractive index of light in the silicon-based epoxy resin is approximately 1.58.

[0111] Depend on Figure 2 and Figure 3The experimental results show that using nano-sized titanium dioxide powder as a dopant in silicone epoxy resin encapsulant has little impact on the transmittance of light with wavelengths above 450 nm when the concentration is low (e.g., less than 0.1% by weight). The decrease in transmittance is not significant. Furthermore, as the proportion of titanium dioxide gradually increases to 0.1% by weight, the refractive index of the titanium dioxide-doped silicone epoxy resin increases from 1.51 to approximately 1.61. However, when the doping exceeds 0.5% by weight, the titanium dioxide particles tend to aggregate, preventing them from maintaining a dispersed state. This hinders the increase in light efficiency through particle-to-particle refraction and may lead to Rayleigh scattering, resulting in a significant decrease in transmittance.

[0112] Therefore, in some embodiments of the light-emitting diode device disclosed herein, two lenses are provided, with different concentrations of titanium dioxide added to the silicon-based epoxy resin respectively, wherein the first lens is configured to increase light extraction efficiency and the second lens is configured to change the light pattern.

[0113] Please refer to Figure 4A The diagram illustrates a light-emitting diode (LED) device 100 according to some embodiments of the present disclosure. The LED device 100 includes a substrate 110 and an LED structure 120. The LED structure 120 is situated on the substrate 110. The LED structure 120 includes a first bonding pad 132, a second bonding pad 134, an LED chip 140, a first lens 150, and a second lens 160.

[0114] In some embodiments, one or more light-emitting diode structures 120 may be disposed above a substrate 110, which may be, for example, a printed circuit board. In some embodiments, the substrate 110 is coated with white paint with a reflectivity of 80% to 90%, such that light emitted by the light-emitting diode chip 140 toward the substrate 110 is reflected away.

[0115] A light-emitting diode (LED) chip 140 is disposed on a substrate 110 and electrically connected to the substrate 110 via a first pad 132 (e.g., a positive pad) and a second pad 134 (e.g., a negative pad). In some embodiments, the LED chip 140 is also fixed to the substrate 110 by an adhesive, such as epoxy resin.

[0116] In some embodiments, the light-emitting diode chip 140 is a blue light-emitting diode chip, such as a gallium nitride (GaN) or gallium phosphide (GaP) chip, emitting light with a wavelength between 430 and 480 nanometers, for example, 440 to 460 nanometers.

[0117] A first lens 150 is disposed above a light-emitting diode (LED) chip 140. In some embodiments, the first lens 150 directly contacts the LED chip 140. The material of the first lens 150 comprises a silicon-based epoxy resin and contains titanium dioxide particles at a weight percentage of 0.01 to 0.5%. The titanium dioxide particles have a particle size smaller than 1 / 10 of the wavelength of light emitted by the LED chip 140, for example, less than 40 nanometers.

[0118] In some embodiments, titanium dioxide particles are mixed with a silicon-based epoxy resin and then molded onto a light-emitting diode chip 140 to form a first lens 150.

[0119] The first lens 150 is configured to increase the light extraction efficiency. According to Snell's Law, when light enters a less dense medium from an optically denser medium at an angle of incidence greater than the critical angle, the light will no longer refract, will stop entering the other medium, and will be completely reflected back to the denser medium; this is called total internal reflection. If a gallium nitride (GaN) wafer is used, its refractive index n = 2.5, making it an optically denser medium. If the refractive index of the encapsulant outside the wafer differs too much from that of the wafer, according to Snell's Law, most of the light will be reflected back into the wafer, thus affecting the light extraction efficiency. In known LED devices, the refractive index of the silicone resin encapsulant in contact with the wafer is approximately between 1.4 and 1.51, therefore, it also affects the light extraction efficiency.

[0120] In contrast, in the embodiments disclosed herein, the first lens 150 in the light-emitting diode structure 120 uses a silicon-based epoxy resin with a certain proportion of titanium dioxide added, forming a polygonal geometric shape to directly contact the light-emitting diode chip 140. Because the first lens 150 is molded, it can be bonded to the light-emitting diode chip 140. Furthermore, since the first lens 150 contains approximately 0.01 to approximately 0.5% by weight of titanium dioxide, the refractive index of the light in the first lens 150 can be increased to approximately 1.61. Therefore, reflection can be reduced compared to known technologies, increasing the light extraction efficiency of the light-emitting diode device 100.

[0121] Please refer to the following: Figure 4A The second lens 160 is disposed above or outside the first lens 150. In some embodiments, the second lens 160 directly contacts the first lens 150. The material of the second lens 160 comprises a silicon-based epoxy resin and contains titanium dioxide particles at a density between 0.5 and 2% by weight. The titanium dioxide particles have a particle size smaller than 1 / 10 of the wavelength of light emitted by the light-emitting diode chip 140, for example, less than 40 nanometers.

[0122] In some embodiments, titanium dioxide particles are mixed with a silicon-based epoxy resin, and then the second lens 160 is formed on the first lens 150 by molding. In other words, the second lens 160 is formed in a similar manner to the first lens 150, except that a higher proportion of titanium dioxide particles are mixed in.

[0123] In other embodiments, a silicon-based epoxy resin layer may be first formed on the first lens 150 by molding, and then a titanium dioxide thin film may be deposited on the silicon-based epoxy resin layer by, for example, vacuum deposition process, to form the second lens 160.

[0124] The second lens 160 is configured to alter the light pattern. By adjusting the titanium dioxide content of the silicon epoxy resin layer to between 0.5 and 2% by weight, the refractive index of the second lens 160 is lower than that of the first lens 150, thereby reducing the light transmittance in the silicon epoxy resin material and achieving the effect of altering the light pattern.

[0125] According to the foregoing Figure 2 and Figure 3 In experiments, when the concentration of titanium dioxide in the silicon-based epoxy resin is high, the titanium dioxide particles aggregate, turning small particles into large particles. These large particles have a diameter exceeding 1 / 10 of the blue light wavelength, resulting in Rayleigh scattering and a decrease in blue light transmittance. The second lens 160 is designed to utilize Rayleigh scattering to increase light scattering, thereby reducing the transmittance of light directly above, increasing light reflection, and refracting some of the light back, thus altering the light pattern distribution.

[0126] Please refer to Figure 4B and Figure 4C They are respectively Figure 4A The ray tracing plot and candela plot / light distribution curve of the light-emitting diode device 100 are shown. The light transmittance directly above the light-emitting diode device 100 decreases, causing some of the light to be refracted again. Therefore, the light pattern distribution of the light-emitting diode device 100 is as follows: Figure 4C The image shows a bat wing shape. Therefore, the LED device 100 can achieve a smaller mixing distance and module thickness.

[0127] In comparison, known light-emitting diode devices, such as Figure 1A The light-emitting diode device 10 shown requires an additional secondary optical lens outside the package structure to achieve the desired effect. Figure 4C The field pattern distribution of light is shown.

[0128] In some embodiments, the amount of titanium dioxide added to the second lens 160 can be adjusted according to the light pattern requirements. For example, when a higher light intensity is required directly above the LED device, a lower amount of titanium dioxide is added to the second lens 160; when a lower light intensity is required directly above the LED device, a higher amount of titanium dioxide is added to the second lens 160.

[0129] In some embodiments, the first lens 150 and the second lens 160 are planar layers. In other embodiments, the first lens 150 and the second lens 160 may be arc-shaped layers, for example, they may be convex or concave.

[0130] In some embodiments, the light-emitting diode structure 120 is formed on the substrate 110. That is, the light-emitting diode chip 140 is electrically connected to the substrate via the first bonding pad 132 and the second bonding pad 134, and the light-emitting diode chip 140 and the substrate 110 are bonded together with an adhesive. Then, a first lens 150 is formed above the light-emitting diode chip 140, and a second lens 160 is formed above the first lens 150.

[0131] In other embodiments, a first lens 150 is formed on a light-emitting diode chip 140, and then a second lens 160 is formed on the first lens 150. Subsequently, the light-emitting diode structure 120 is electrically connected to the substrate 110 via a first pad 132 and a second pad 134, and the light-emitting diode chip 140 and the substrate 110 are bonded together with an adhesive.

[0132] Please refer to Figure 5A The diagram illustrates a light-emitting diode (LED) device 200 according to some embodiments. In the LED device 200, the LED package structure 220 is a fully encapsulated package. A first lens 250 and a second lens 260 cover the top surface 242 and side surface 244 of the LED chip 240. The LED chip 240 is disposed on a substrate 210 and is electrically connected to the substrate 210 via a first bonding pad 232 and a second bonding pad 234.

[0133] In some embodiments, the width of the light-emitting diode chip 240 is a first dimension D1, and the width of the second lens 260 is a second dimension D2, wherein the second dimension D2 is less than or equal to 1.2 times the first dimension D1. Therefore, the light-emitting diode package structure 220 is a chip-level package structure.

[0134] Please refer to Figure 5BThe diagram illustrates a light-emitting diode (LED) device 300 according to some other embodiments. In the LED device 300, the LED package structure 320 is a fully enclosed polygonal package. A first lens 350 and a second lens 360 cover the top and side surfaces of the LED chip 340. The LED chip 340 is disposed on a substrate 310 and is electrically connected to the substrate 310 via a first pad 332 and a second pad 334.

[0135] The thickness of the first lens 350 on the top surface of the LED chip 340 is a first thickness T1, and the thickness of the first lens 350 on the side surface of the LED chip 340 is a second thickness T2. In some embodiments, the first thickness T1 is not equal to the second thickness T2. The first thickness T1 and the second thickness T2 of the first lens 350 can be adjusted as needed to achieve the desired light extraction efficiency of the top and side surfaces of the LED package structure 320.

[0136] The second lens 360 has a thickness of a third thickness T3 on the top surface of the light-emitting diode chip 340, and a thickness of a fourth thickness T4 on the side surface of the light-emitting diode chip 340. In some embodiments, the third thickness T3 is not equal to the fourth thickness T4. In an embodiment where the second lens 360 is formed by depositing a titanium dioxide thin film over a silicon-based epoxy resin layer, the required titanium dioxide content in the second lens 360 can be achieved by adjusting the thickness of the silicon-based epoxy resin. The third thickness T3 and the fourth thickness T4 can be adjusted as needed to achieve the ideal light field distribution on the top and side surfaces of the light-emitting diode package structure 320.

[0137] Please refer to Figure 6A The diagram illustrates a light-emitting diode (LED) package structure 420 according to some embodiments. The main difference between LED package structure 420 and LED package structures 220 and 320 is that it has a support 422. The support 422 may be, for example, a ceramic material or an epoxy resin material.

[0138] In the LED package structure 420, a first bonding pad 432 is electrically connected to a via 424 and a first extended bonding pad 426 in the bracket 422. A second bonding pad 434 is electrically connected to a via 424 and a second extended bonding pad 428 in the bracket 422. A first lens 450 is located above the bracket 422 and covers the LED chip 440. A second lens 460 is located above the bracket and covers the first lens 450.

[0139] Please refer to Figure 6BThe diagram illustrates a light-emitting diode (LED) package structure 520 according to some embodiments. The LED package structure 520 is a single-sided light-emitting package structure. A protective layer 570 is located on the side 544 of the LED chip 540, and the protective layer 570 is composed of an opaque material. A first lens 550 is located above the protective layer 570 and covers the top surface 542 of the LED chip 540. A second lens 560 covers the first lens 550.

[0140] The light-emitting diode (LED) device shown in the embodiments disclosed herein has a structure in which two microlenses, namely a first lens and a second lens, are disposed above the LED chip. In some embodiments, such a structure can be applied to, for example, but not limited to, packaging structures for mini LEDs or micro LEDs, such as chip-level packaging or wafer-level packaging.

[0141] The light-emitting diode devices of the embodiments disclosed herein can be applied to, for example, but not limited to, displays or lighting devices, such as backlights for displays (e.g., direct-lit backlight modules or edge-lit backlight modules), flashlights, projectors, high-intensity lighting fixtures (e.g., vehicle lights, searchlights, flashlights, work lights, outdoor high-bay lights, landscape lights, etc.), and small-angle lighting fixtures.

[0142] Taking the backlight of a display as an example, Table 1 below compares the differences between backlights made using known light-emitting diode (LED) devices and those made using the LED devices disclosed herein.

[0143] Table 1

[0144]

[0145] Please refer to Figure 7 An exploded view of a backlight module 700 for a display is shown. The backlight module 700 includes a backplate 710, an LED strip 720, a backlight cavity 730, and multiple optical films 740.

[0146] Multiple light strips 720 are disposed on a back plate 710, each light strip including a circuit board 722 and a light-emitting diode assembly 724. The light-emitting diode assembly 724 has a first lens and a second lens as described above.

[0147] The backlight cavity 730 is located above the back panel 710 and the lamp strip 720. The bottom of the backlight cavity 730 has a plurality of openings 732, which correspond to a plurality of light-emitting diode assemblies 724 respectively. In some embodiments, the backlight module 700 is applied to a thin display, and the height of the backlight cavity 730 is less than 10 millimeters (mm).

[0148] Multiple optical films 740 are disposed above the backlight cavity 730. The optical films may be, for example, diffusers, prism sheets, diffuser plates, or similar, to adjust the optical characteristics of the backlight module 700 as needed.

[0149] Some embodiments of this disclosure provide a display that is a thin device having an optical cavity with a height of less than 10 mm. Figure 4A , Figure 5A , Figure 5B , Figure 6A ,or Figure 6B The LED device or LED package structure of the discussed embodiments can therefore omit the design of secondary optical lenses and achieve better light extraction efficiency and light mixing uniformity in thin displays or other lighting devices with small optical cavity heights.

[0150] The foregoing outlines features of several embodiments to enable those skilled in the art to better understand various aspects of this disclosure. Those skilled in the art will understand that they may readily use this disclosure as a basis for the design or modification of other processes and structures to achieve the same purpose or advantages as the embodiments described herein. Those skilled in the art will also understand that equivalent constructions do not depart from the spirit and scope of this disclosure, and that various changes, substitutions, and modifications may be made without departing from the spirit and scope of the appended claims.

Claims

1. A light-emitting diode device, characterized in that, Include: A light-emitting diode chip; and A package structure encapsulating the light-emitting diode chip, wherein the package structure includes: A first lens is positioned above and in direct contact with the light-emitting diode chip, the first lens being configured to increase light extraction efficiency, and the first lens containing a first amount of titanium dioxide; and A second lens, above and in direct contact with the first lens, the second lens being configured to change the light pattern, the second lens containing a second amount of titanium dioxide; The second content of titanium dioxide is greater than the first content of titanium dioxide.

2. The light-emitting diode device according to claim 1, characterized in that, The materials of the first lens and the second lens include silicon-based epoxy resin.

3. The light-emitting diode device according to claim 1, characterized in that, The first content of titanium dioxide in the first lens is in the range of 0.01 to 0.5 weight percentage of the first lens.

4. The light-emitting diode device according to claim 1, characterized in that, The second content of titanium dioxide in the second lens is in the range of 0.5 to 2 weight percentages of the second lens.

5. The light-emitting diode device according to claim 1, characterized in that, The particle size of the titanium dioxide in the first lens and the titanium dioxide in the second lens is less than 1 / 10 of the wavelength of the emitted light from the light-emitting diode.

6. A light-emitting diode device, characterized in that, Include: A light-emitting diode chip; and A package structure encapsulating the light-emitting diode chip, wherein the package structure includes: A first lens, located above and in direct contact with the LED chip, the first lens comprising less than 0.5% by weight of titanium dioxide; and A second lens, located above and in direct contact with the first lens, comprises more than 0.5% by weight of titanium dioxide.

7. The light-emitting diode device according to claim 6, characterized in that, The refractive index of the light from the second lens is less than that of the light from the first lens.

8. The light-emitting diode device according to claim 6, characterized in that, The light transmittance of the second lens is less than that of the first lens.

9. The light-emitting diode device according to claim 6, characterized in that, The titanium dioxide particles in the first lens and the titanium dioxide particles in the second lens have a particle size of less than 40 nanometers.

10. A display, characterized in that, The display comprises a light-emitting diode device according to any one of claims 1 to 9, and the display has a light cavity with a height of less than 10 mm.

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