TWI867320B - Pixel package and display device - Google Patents

Abstract

A pixel package is provided to include: a carrier board, a pixel, a reflective layer, and a light-absorbing layer. The pixel is disposed on the carrier board, and includes: a first light-emitting unit having a first light-emitting surface; a second light-emitting unit having a second light-emitting surface; and a wavelength conversion layer disposed on the second light-emitting surface and having a third light-emitting surface. The reflective layer has a first portion and a second portion, and surrounds the first light-emitting unit and the second light-emitting unit. The first portion has a second upper surface coplanar with the first light-emitting surface, and the second portion is on the first portion and has a third upper surface. The light-absorbing layer is disposed on the third upper surface. The third upper surface is located between the second light-emitting surface and the third light-emitting surface in a vertical direction. A thickness ratio of the light-absorbing layer to the second portion, measured in a direction perpendicular to the first light-emitting surface, is larger than 0 and less than or equal to 1/5.

Description

Pixel package and display device

The present disclosure relates to a pixel package and a display device, and in particular to a pixel package and a display device having a sub-millimeter light-emitting diode.

Light-emitting diodes (LEDs) have the characteristics of low power consumption, low heat generation, long operating life, impact resistance, small size, and fast response speed. Therefore, they can be used in various fields that require the use of light-emitting components, such as lighting, medical treatment, display, communication, sensing, power supply systems, etc.

With the advancement of technology, the size of optoelectronic semiconductor components has gradually developed towards miniaturization. In recent years, due to breakthroughs in the size of LED manufacturing, sub-millimeter LED (Mini Light-Emitting Diode; Mini LED) displays, which are made by arranging LEDs in arrays, have gradually attracted attention in the market. Compared with organic light-emitting diode (Organic Light-Emitting Diode; OLED) displays, sub-millimeter LED displays are more power-saving, have better reliability, longer service life, better contrast performance, and higher brightness, and can be visible in sunlight.

Furthermore, to facilitate the use of LED dies in display applications, a pixel package containing the LED dies may be used. The pixel package typically uses an encapsulation layer (e.g., a transparent epoxy or silicone material surrounding the LED die) to protect the LED die from physical damage or environmental conditions that cause corrosion or degradation.

In a conventional pixel package, two adjacent LED chips are separated by a packaging layer. The packaging layer includes a wavelength conversion layer and a transparent packaging adhesive. Because light from the LED chips passes through the packaging layer, the pixel package or a display device using the conventional pixel package may have problems such as light crosstalk, low contrast, and poor light extraction efficiency.

The disclosed embodiment provides a pixel package, comprising: a carrier having a first upper surface; a pixel disposed on the first upper surface, comprising: a first light emitting unit, a second light emitting unit, and a wavelength conversion layer, wherein the first light emitting unit has a first light emitting surface and a first side surface, the second light emitting unit has a second light emitting surface and a second side surface, and the second side surface faces the first side surface, and the wavelength conversion layer is disposed on the second light emitting surface and has a third light emitting surface and a third side surface; A reflective layer is arranged between the first side surface and the second side surface and has a first part and a second part, wherein the second part is located on the first part and has a third upper surface; and a light absorbing layer is arranged on the third upper surface of the second part; wherein the height of the third upper surface of the second part is between the second light emitting surface and the third light emitting surface, wherein, measured from a direction perpendicular to the first upper surface, the ratio of the thickness of the light absorbing layer to the second part is greater than 0 and less than or equal to 1/5.

The disclosed embodiment provides a display device, comprising: a display substrate having a first side and a second side opposite to each other; a pixel located on the first side of the display substrate, comprising: a first light emitting unit, a second light emitting unit and a wavelength conversion layer, the first light emitting unit having a first light emitting surface and a first side surface, the second light emitting unit having a second light emitting surface and a second side surface, and the second side surface and the first side surface are opposite to each other, the wavelength conversion layer is arranged on the second light emitting surface and has a third light emitting surface and a third side surface; a reflective layer, disposed between the first side surface and the second side surface, and having a first portion and a second portion, wherein the second portion is located on the first portion and has a third upper surface; and a light absorbing layer, disposed on the third upper surface of the second portion; wherein the height of the third upper surface of the second portion is between the second light emitting surface and the third light emitting surface, wherein, measured from a direction perpendicular to the first upper surface, a thickness ratio of the light absorbing layer to the second portion is greater than 0 and less than or equal to 1/5.

The following disclosure provides a number of embodiments or examples for implementing different elements of the subject matter provided. Specific examples of each element and its configuration are described below to simplify the description of the disclosed embodiments. Of course, these are merely examples and are not intended to limit the disclosed embodiments. For example, if the description refers to a first element formed on a second element, it may include an embodiment in which the first and second elements are directly in contact, and it may also include an embodiment in which additional elements are formed between the first and second elements so that they are not directly in contact. In addition, the disclosed embodiments may use repeated element symbols in various examples. Such repetition is for the purpose of simplicity and clarity, and is not used to indicate the relationship between the different embodiments and/or configurations discussed.

Furthermore, spatially relative terms such as "below," "below," "below," "above," "above," and similar terms may be used herein to describe the relationship between an element or component and other elements or components as shown in the figures. These spatial terms are intended to include different orientations of the device in use or operation in addition to the orientations shown in the drawings. For example, if the device in the figure is reversed, an element originally described as "below" or "below" other elements or components will be turned "above" other elements or components. Therefore, the exemplary term "below" can have both "above" and "below" orientations. When the device is rotated to other orientations (rotated 90° or other orientations), the spatially relative descriptions used herein can also be interpreted based on the rotated orientation.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meanings as those understood by those of ordinary skill in the art to which the present disclosure belongs. It should be understood that these terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with the background or context of the relevant technology and the present disclosure, and should not be interpreted in an idealized or overly formal manner unless specifically defined in the present disclosure embodiments.

The present disclosure provides a pixel package and a display device that uses a dual-color baffle packaging layer structure to surround a light-emitting diode die, wherein the dual-color baffle packaging layer structure includes a black light-absorbing layer and a white reflective layer, wherein the black light-absorbing layer can prevent light crosstalk and increase contrast, and the white reflective layer can increase light output. In addition, the present disclosure increases light output brightness and maintains the black contrast of the surface by making the ratio of the thickness of the light-absorbing layer to the thickness of the portion of the reflective layer located above the light-emitting diode die greater than 0 and less than or equal to 1/5. Furthermore, the present disclosure changes the light output angle of the pixel package by making the angle between the reflective layer and the upper surface of the light-emitting diode die a right angle or a blunt angle, thereby further improving the light output brightness.

[Pixel package]

FIG. 1A is a top view of a pixel package 10 according to an embodiment. As shown in FIG. 1A , from the top view of the pixel package 10 , the light absorbing layer 420 completely covers the reflective layer (not shown) and exposes the pixel 200 , wherein the pixel 200 includes a first light emitting unit 210 , a second light emitting unit 220 , and a third light emitting unit 230 .

FIG. 1B is a top view of a multi-pixel package 20 according to another embodiment. The multi-pixel package 20 has a similar structure to the pixel package 10 shown in FIG. 1A above, except that the multi-pixel package 20 includes a plurality of groups of pixels 200. In one embodiment, the multi-pixel package 20 includes four groups of pixels 200. In the multi-pixel package 20, in two adjacent pixels 200, two adjacent LEDs belonging to different pixels 200 emit the same wavelength. And any two adjacent LEDs in any pixel 200 are separated from each other by a fixed distance. Specifically, as shown in FIG. 1B , between two adjacent pixels 200 arranged horizontally (along the X axis), the distance between two adjacent first light emitting units 210 belonging to different pixels 200 is D1; between two adjacent pixels 200 arranged vertically (along the Y axis), the distance between two adjacent first light emitting units 210 belonging to different pixels 200 is D2, and D1 is the same as D2. The detailed structures of the first light emitting unit 210, the second light emitting unit 220, and the third light emitting unit 230 will be described later.

The first light-emitting unit 210, the second light-emitting unit 220, and the third light-emitting unit 230 may be sub-millimeter light-emitting diodes (Mini Light-Emitting Diode; Mini LED), and in the top view (FIG. 1A, FIG. 1B), have a length L and a width W. The length L is 90 μm to 225 μm, preferably 90 μm to 150 μm, for example: 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm. The width W is 40 μm to 125 μm, preferably 40 μm to 90 μm, for example: 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm.

FIG. 2 is a cross-sectional schematic diagram of the pixel package 10 of FIG. 1A or a cross-sectional schematic diagram of one group of pixels 200 of the multi-pixel package 20 of FIG. 1B. As shown in FIG. 2, the pixel package includes a carrier 100, a pixel 200, a reflective layer 410, a light absorbing layer 420, and a light-transmitting layer 600. The reflective layer 410 and the light absorbing layer 420 form a barrier structure 400 with dual colors, dual reflectivity and/or dual light absorption. In one embodiment, the carrier 100 has a first upper surface 110t1 and a first lower surface 110t2 opposite to each other, and includes an insulating layer 110, an upper conductive layer 120, a plurality of conductive vias (not shown), and a lower conductive layer 130. The upper conductive layer 120 and the lower conductive layer 130 are respectively located on the first upper surface 110t1 and the first lower surface 110t2 of the insulating layer 110, and a plurality of conductive through holes penetrate the insulating layer 110 to electrically connect the upper conductive layer 120 and the lower conductive layer 130, wherein the upper conductive layer 120 can be electrically connected to the pixel 200 and the lower conductive layer 130, and the lower conductive layer 130 can be electrically connected to the external control circuit.

The material of the insulating layer 110 may be epoxy resin, BT resin (Bismaleimide Triazine), polyimide, a composite material of epoxy resin and glass fiber, a composite material of BT resin and glass fiber, or a composite material of polyimide and glass fiber. The materials of the upper conductive layer 120 and the lower conductive layer 130 may be the same or different, and the materials include metals, such as copper, tin, aluminum, silver, gold, alloys of the above materials, or stacks of the above materials.

As shown in FIG. 2 , the pixel 200 is disposed on the first upper surface 110t1 of the carrier 100, and includes a plurality of light emitting units on the carrier 100, for example, a first light emitting unit 210, a second light emitting unit 220, and a third light emitting unit 230. The first light emitting unit 210 has a first light emitting surface 210S and a first side surface 210W; the second light emitting unit 220 has a second light emitting surface 220S and a second side surface 220W; and the third light emitting unit 230 has a fourth light emitting surface 230S. In one embodiment, the pixel 200 further includes a wavelength conversion layer 500, which is disposed on the second light emitting surface 220S of the second light emitting unit 220 and has a third light emitting surface 500S and a third side surface 500W.

In one embodiment, the first light emitting unit 210, the second light emitting unit 220, and the third light emitting unit 230 may be LED dies that emit light of different wavelengths or colors, and the material compositions of the first light emitting unit 210, the second light emitting unit 220, and the third light emitting unit 230 are not completely the same. In another embodiment, the third light emitting unit 230 is a red light emitting diode die, which can emit a first light ray by providing an electric power to the power source, and the dominant wavelength (Dominant Wavelength) or peak wavelength (Peak Wavelength) of the first light ray is between 600 nm and 660 nm. The second light emitting unit and the first light emitting unit 210 are blue light emitting diode die, wherein the second light emitting unit 220 and the third light emitting unit 230 can respectively emit a second light ray and a third light ray of the same color light, and the dominant wavelength (Dominant Wavelength) or peak wavelength (Peak Wavelength) of the second light ray and the third light ray is between 430 nm and 480 nm, wherein the second light ray emitted by the second light emitting unit 220 is converted into a dominant wavelength (Dominant Wavelength) or a peak wavelength (Peak Wavelength) between 510 nm by the wavelength conversion layer 500 located above it. nm to 560 nm. The third light-emitting surface 500S of the wavelength conversion layer 500 can be a plane or a curved surface. For example, as shown in FIG. 2, when the wavelength conversion layer 500 is filled with a curable wavelength conversion material that is originally in a liquid state, the third light-emitting surface 500S is affected by the surface tension during the manufacturing process and becomes a concave arc. The curable wavelength conversion material is composed of a wavelength conversion material and a substrate. The substrate may include silicone, epoxy, acrylic resin, polyimide, or a mixture of the above materials; the wavelength conversion material may include a fluorescent powder material or a quantum dot material. Suitable phosphor materials include doped garnets (such as YAG:Ce and (Y, _{Gd)AG:Ce), aluminates (such as Sr2Al14O25 :} Eu and BAM:Eu), silicates (such as SrBaSiO:Eu), sulfides (such as ZnS:Ag, CaS:Eu and _SrGa2S4 :Eu), oxysulfides, oxynitrides, phosphates, borates and tungstates (such _{as CaWO4} ); suitable quantum dot materials include Si, Ge, CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, PbS, PbSe, PbTe, InN, InP, InAs, AlN, AlP, AlAs, GaN, GaP, GaAs and combinations thereof.

FIG. 3A and FIG. 3B show enlarged cross-sectional views of the first light emitting unit 210 and the barrier structure 400 in the dotted line portion of FIG. 2. The second light emitting unit 220 and the third light emitting unit 230 have similar structures, except that a wavelength conversion layer 500 is provided above the second light emitting unit 220. In one embodiment, as shown in FIG. 3A and FIG. 3B, the light emitting unit 210 is a flip-chip. The light emitting unit 210 at least includes a light emitting layer 216, a p-type semiconductor layer 218 and an n-type semiconductor layer 214 located on both sides of the light emitting layer 216, a growth substrate 212, a p-type contact electrode 218c, and an n-type contact electrode 214c. The p-type contact electrode 218c and the n-type contact electrode 214c are electrically connected to the p-type semiconductor layer 218 and the n-type semiconductor layer 214 respectively through the solder 300. In one embodiment, the light-emitting unit 210 does not include the growth substrate 212 or includes a thinned growth substrate. The outer wall of the light-emitting layer 216 is surrounded by the reflective layer 410, so the light emitted by the light-emitting layer 216 will not directly radiate to other adjacent light-emitting units, so that the light can only leave the pixel package 10 or the multi-pixel package 20 from the first light-emitting surface 210S.

Referring to FIG. 2 , the reflective layer 410 respectively surrounds the first light emitting unit 210, the second light emitting unit 220, and the third light emitting unit 230. In a top view (not shown), the reflective layer 410 completely surrounds the first light emitting unit 210, the second light emitting unit 220, and the third light emitting unit 230. For example, the reflective layer 410 is disposed between the first side surface 210W of the first light emitting unit 210 and the second side surface 220W of the second light emitting unit 220. The reflective layer 410 also has a first portion 412 and a second portion 414, and the first portion 412 has a second upper surface 412t coplanar with the first light emitting surface 210S of the first light emitting unit 210. The second portion 414 is located on the first portion 412 and has a third upper surface 414t. The side wall of the second portion 414 is coplanar with the side wall of the first portion 412, and the height of the third upper surface 414t of the second portion 414 is between the second light emitting surface 220S of the second light emitting unit 220 and the third light emitting surface 500S of the wavelength conversion layer 500, so that the light emitted by the first light emitting unit 210 and the light emitted by the second light emitting unit 220 after conversion by the wavelength conversion layer 500 are reflected, thereby improving the brightness of the light. In addition, since the reflective layer 410 covers the side wall 210W of the first light emitting unit 210, the second side surface 220W of the second light emitting unit 220, and the side wall of the third light emitting unit 230, the light emitted by the first light emitting unit 210, the second light emitting unit 220, and the third light emitting unit 230 in the pixel package can only be emitted from the first light emitting surface 210S, the second light emitting surface 220S, and the fourth light emitting surface 230. 230S is emitted, and the light emitted from the side wall 210W of the first light emitting unit 210, the second side surface 220W of the second light emitting unit 220, and the side wall of the third light emitting unit 230 is completely blocked by the reflective layer 410, thereby avoiding light crosstalk between the first light emitting unit 210, the second light emitting unit 220, and the third light emitting unit 230, thereby improving the color purity and contrast of the pixel package.

In some embodiments, the material of the first portion 412 may be the same as the material of the second portion 414. In other embodiments, the material of the first portion 412 may be different from the material of the second portion 414, wherein the reflectivity of the first portion 412 may be greater than the reflectivity of the second portion 414, and the material of the first portion 412 may be a non-exposure developing type, so there is no need to consider the exposure factor, so the content of the added reflective particles can be higher, so as to have a greater reflectivity, thereby improving the brightness. In detail, the reflectivity of the first portion 412 is, for example, greater than 95%, and the reflectivity of the second portion 414 is, for example, in the range of 90 to 91%.

Continuing to refer to FIG. 2, the light absorbing layer 420 is disposed on the third upper surface 414t of the second portion 414 and surrounds the first light emitting unit 210 and the second light emitting unit 220. As shown in the enlarged views of FIG. 3A and FIG. 3B, the first portion 412 and the second portion 414 of the reflective layer 410 have a first thickness H1 and a second thickness H2, respectively, wherein the first thickness H1 is greater than the second thickness H2. In addition, the light absorbing layer 420 has a third thickness H3, wherein, measured from a direction perpendicular to the first upper surface 110t1, the thickness ratio (H3/H2) of the light absorbing layer 420 to the second portion 414 is greater than 0 and less than or equal to 1/5, so that the large-angle light emitted by the first light emitting unit 210 and the large-angle light emitted by the second light emitting unit 220 after conversion by the wavelength conversion layer 500 can be reflected by the reflective layer 410 instead of being absorbed by the light absorbing layer 420, thereby improving the brightness of the light and reducing crosstalk and maintaining contrast. In detail, the thickness H2 of the second portion 414 is 5 Up to 20 The thickness H3 of the light absorbing layer 420 is within the range of 0.1 to 1 According to the inventor's research, if the thickness ratio (H3/H2) is greater than 1/5, the improvement in light output brightness will become smaller.

In addition, from the cross-sectional view (as shown in FIG. 3A and FIG. 3B), the light absorbing layer 420 has a first maximum opening 420o on the first light emitting unit 210, and the second portion 414 has a second maximum opening 414o on the first light emitting unit 210. In one embodiment, as shown in FIG. 3A, the angle between the side wall of the second portion 414 in the second maximum opening 414o and the first light emitting surface 210S of the first light emitting unit 210 is The width of the first maximum opening 420o of the light absorbing layer 420 is equal to the width of the second maximum opening 414o of the second portion 414, and the light output angle is about 80 to In another embodiment, as shown in FIG. 3B , the angle between the side wall of the second portion 414 within the second maximum opening 414o and the first light emitting surface 210S of the first light emitting unit 210 is The corners are blunt, so that the portion of the baffle structure 400 located above the first light-emitting surface 210S is in an "inverted trapezoidal" shape in the cross-sectional view. The blunt angle is preferably 120 Up to 130 In addition, in the cross-sectional view, the width of the first maximum opening 420o is greater than the width of the first light emitting surface 210S, and the width of the second maximum opening 414o is less than the width of the first maximum opening 420o and greater than the width of the first light emitting surface 210S. With such a design, the light emitting angle can be further increased to 100 Up to 115 And further enhance the light brightness.

The material of the light absorbing layer 420 includes a matrix and a light absorbing material, wherein the matrix includes silicone, epoxy, acrylic resin, polyimide or a mixture of the above materials, and the light absorbing material includes carbon black and dark dyes. The light transmittance of the light absorbing layer 420 is lower than the light transmittance of the light transmissive layer 600, or the light absorbance of the light absorbing layer 420 is higher than the light transmittance of the light transmissive layer 600. By adjusting the concentration of the light absorbing material in the matrix, the light transmittance of the light absorbing layer 420 is lower than 30%, that is, the light absorbing layer 420 is almost or completely opaque.

As shown in FIG. 2 , the light-transmitting layer 600 is disposed on the first upper surface 110t1 and covers the light-absorbing layer 420, the first light-emitting unit 210, the second light-emitting unit 220, and the third light-emitting unit 230. As shown in FIG. 3A and FIG. 3B , the light-transmitting layer 600 completely fills the space enclosed by the first light-emitting surface 210S, the reflective layer 410, and the light-absorbing layer 420. The material of the light-transmitting layer 600 includes silicone, epoxy, acrylic resin, a mixture of the above materials, or a stack of the above materials. In one embodiment, the light transmittance of the light-transmitting layer 600 is greater than 90%. In addition, the hardness of the light-absorbing layer 420 may be less than the hardness of the light-transmitting layer 600. For example, the Shore D hardness of the light absorbing layer 420 is less than 60, and the Shore D hardness of the light transmitting layer 600 is greater than 60, so that the pixel package has the ability to resist scratches and wear.

[Pixel package manufacturing process]

The process of the pixel package can be formed by the following method: providing a supporting base, such as a steel plate, and placing a soft pad on the supporting base, placing a film on the soft pad, wherein the film includes a supporting film, a rubber film, and a release layer between the supporting film and the rubber film, wherein the rubber film can be a semi-cured (B-stage) film, and the material includes silicone, epoxy, polyurethane (PU), thermoplastic polyurethane (TPU), or a mixture thereof. The rubber film includes a reflective material, such as titanium oxide (TiO _x ), silicon oxide (SiO _x ), or a mixture thereof, to form a reflective layer 410, wherein the reflective layer 410 can be white. Next, the carrier 100 with the light-emitting units disposed thereon is placed upside down on the film so that the surface of each light-emitting unit contacts the adhesive film in the film. An air pressure pad is provided on the back side of the carrier 100 (the side without the light-emitting unit) opposite to the light-emitting element, and a pressure is applied to the carrier 100 by the air pressure pad so that the light-emitting element is sunk into the film. During the process, the adhesive film is heated to maintain it in a softened state.

The softened adhesive film is squeezed into the space between adjacent light-emitting units by the air pressure pad and the soft pad. In one embodiment, the air pressure pad will continue to apply pressure until the softened adhesive film completely fills the gap between adjacent light-emitting units and exposes the upper surface and/or part of the side surface of the light-emitting unit. When the adhesive film fills the gap between adjacent light-emitting units and reaches a predetermined thickness, the heating is stopped and the film is left to stand for a period of time. After the adhesive film is cured to form a solid adhesive layer, the pressure of the air pressure pad is released, and the release layer and the supporting film are removed.

Next, the glue layer on the light-emitting unit is removed by a dry etching process to form a first portion 412 of the reflective layer 410 coplanar with the surface of the light-emitting unit. The dry etching process uses gases including argon (Ar), oxygen-containing gas, ozone-containing gas, fluorine-containing gas (e.g., tetrafluoromethane (CF ₄ ), sulfur hexafluoride (SF ₆ ), difluoromethane (CH ₂ F ₂ ), trifluoromethane (CHF ₃ ) and/or hexafluoroethane (C ₂ F ₆ )), chlorine-containing gas (e.g., chlorine (Cl ₂ ), chloroform (CHCl ₃ ), carbon tetrachloride (CCl ₄ ), and/or boron trichloride (Boron trichloride)). Trichloride; BCl ₃ )), bromine-containing gas (e.g., hydrogen bromide (HBr) and/or bromoform (CHBr ₃ )), iodine-containing gas, other suitable etching gas and/or plasma, or a combination thereof.

After the dry etching process for removing the glue, a white photoresist layer can be formed on the first portion 412 of the reflective layer 410 by a coating process. Then, the white photoresist layer is exposed to specific light for exposure. Then, the exposed white photoresist layer is developed to form the second portion 414 of the reflective layer 410 on the first portion 412 of the reflective layer 410. After the second portion 414 of the reflective layer 410 is formed, the light absorbing layer 420 can be formed by a process similar to that of forming the second portion 414, except that the material coated thereon is a black photoresist layer.

After forming the light absorbing layer 420, the light-transmitting layer 600 is formed by coating or molding. Finally, the insulating layer 110 of the carrier 100 is cut by a cutting tool to form a cutting path. Then, the light-transmitting layer 600 is cut by a cutting tool to form a package. In another embodiment, the light-transmitting layer 600 is separated first and then the insulating layer 110 of the carrier 100 is separated. In another embodiment, the insulating layer 110 of the carrier 100 and the light-transmitting layer 600 can also be separated at the same time in a single step.

[Display device]

FIG. 4 is a top view of a display device 30 according to another embodiment. As shown in FIG. 4, the display device 30 may include a display substrate 140, a pixel 200, a reflective layer (not shown), a light absorbing layer 420, and a light transmitting layer (not shown). The display substrate 140 has a first side 140t1 and a second side 140t2 opposite to each other (refer to FIG. 5), and includes a display area 142 in which the pixel 200 is located, wherein the pixel 200 is located on the first side 140t1 of the display substrate 140. Each pixel 200 includes a plurality of sub-pixels that can emit light of different colors. For example, each pixel 200 includes three sub-pixels (a first light-emitting unit 210, a second light-emitting unit 220 and a wavelength conversion layer 500, and a third light-emitting unit 230) that can respectively emit blue light, green light, and red light. The number of sub-pixels in the pixel 200 may be three or more, and the sub-pixels may present color lights other than the three primary colors (blue, green, and red). For example, a pixel may include sub-pixels that can present four color lights of blue, green, red, and cyan. In addition, the definitions of the first light-emitting unit 210, the second light-emitting unit 220, the third light-emitting unit 230, and the wavelength conversion layer 500 of the pixel 200 are the same as those described above, and will not be repeated here.

The display substrate 140 may be a thin film transistor (TFT) substrate. The base material of the display substrate 140 may be a rigid structure or a flexible structure. For example, the display substrate 140 may be formed of the following rigid materials: glass, silicon, etc.; or formed of the following flexible materials: polymer, metal foil, etc., and the display substrate 140 has a distribution line to electrically connect with the pixel 200 and the micro-driver 144 in the display area. In some embodiments, the display substrate 140 may be a circuit board with a control circuit, and is electrically connected with the pixel 200.

As shown in FIG. 4 , the display device 30 may include a microdriver 144 disposed in a display area corresponding to the pixel 200, a row driver 124 around the display area and/or a motion driver 122 around the display area, and a flexible circuit board 126. The row driver 124 and the motion driver 122 may be used selectively to cooperate with the microdriver 144 to drive the pixel 200. In other words, the pixel 200 may be controlled only by the microdriver 144. The first light emitting unit 210, the second light emitting unit 220, and the third light emitting unit 230 in the pixel 200 can be electrically connected to the corresponding micro driver 144 in the display area driving the first light emitting unit 210, the second light emitting unit 220, and the third light emitting unit 230 through the display substrate 140. The column driver 124 may include a separate driver for each column of light emitting unit sets. The row driver 122 may include a separate driver for each row of light emitting unit sets. The flexible circuit board 126 can be used to electrically connect the display device 30 to an external system.

FIG. 5 is an enlarged cross-sectional view of the dotted line of FIG. 4 according to another embodiment. FIG. 5 is similar to the cross-sectional view of FIG. 2, except that FIG. 5 is a chip on board (COB) structure. The chip on board is to directly mount the bare chip of the LED (the first light emitting unit 210, the second light emitting unit 220, and the third light emitting unit 230) on the display substrate 140. The barrier structure 400 is formed between the LED chips. The packaging glue (transparent layer 600) is applied on the entire surface of the display substrate 140 to cover all the LED chips and the barrier structure.

In another embodiment, the display device is a package on board (POB) structure (not shown). The plurality of pixel packages 10 or multi-pixel packages 20 are arranged in an array on a display substrate 140, and the lower conductive layer of the pixel package 10 or multi-pixel package 20 is electrically connected to the display substrate 140. In addition, the display device may also include a double-color barrier structure 400 of a light absorbing layer 420 and a reflective layer 410, and a light-transmitting layer 600, and the relevant contents may refer to the relevant paragraphs above.

As shown in FIG. 5 , the display substrate 140 further includes a wiring structure 150 located on the first side 140t1, wherein the wiring structure 150 electrically connects the display substrate 140 to the pixel 200. The wiring structure 150 is, for example, a conductive metal such as aluminum, copper, or gold, and is electrically connected to the contact electrode of the aforementioned light-emitting unit through solder 300. In another embodiment, the display device is a structure of a package upper plate (not shown), and the aforementioned plurality of pixel packages 10 or multi-pixel packages 20 are electrically connected to the wiring structure 150 on the first side 140t1 of the display substrate 140 through solder 300 through the lower conductive layer.

[Manufacturing process of display device]

First, a bare die of a light emitting diode (first light emitting unit 210, second light emitting unit 220, and third light emitting unit 230) is transferred from a carrier, such as a growth substrate or a temporary substrate, to a display substrate 140, and the light emitting diode (first light emitting unit 210, second light emitting unit 220, and third light emitting unit 230) and a micro driver 144 are mounted on a first side 140t1 of the display substrate 140. The connection method between the light emitting diode and the micro driver 144 and the display substrate 140 includes but is not limited to a conductive pad, a conductive bump, and a conductive ball. Specifically, the materials suitable for the conductive pads, conductive bumps, and conductive balls may include low melting point metals or alloys with low liquid melting points, whose melting points or liquid temperatures are lower than 210°C, such as bismuth (Bi), tin (Sn), indium (In), or alloys thereof. For example, the n-type contact electrode 214c and the p-type contact electrode 218c on the micro-actuator 144 and the light-emitting diode are thermally pressed and bonded to the wiring structure 150 on the display substrate 140. The barrier structure 400 is formed between the light-emitting diodes. Next, the light-transmitting layer 600 covers the light-emitting diode and the light-absorbing layer 420. The formation method of the above-mentioned barrier structure 400 and the light-transmitting layer 600 can refer to the contents of the above-mentioned relevant paragraphs.

In summary, the present invention provides a pixel package and a display device using a two-color baffle structure surrounding a light-emitting diode, wherein the black light-absorbing layer of the two-color baffle structure can prevent light crosstalk and increase contrast, and the white reflective layer can increase light output and thus improve brightness. In addition, by making the ratio of the thickness of the reflective layer located at the light-emitting diode to the thickness of the light-absorbing layer greater than 0 and less than 1/5, the light output brightness can be further increased while maintaining the black contrast of the surface. Furthermore, by making the angle between the reflective layer and the upper surface of the light-emitting diode a right angle or a blunt angle, the light output angle is increased, thereby improving brightness.

The above summarizes the components of several embodiments so that those with ordinary knowledge in the art to which the present disclosure belongs can more easily understand the perspectives of the embodiments of the present disclosure. Those with ordinary knowledge in the art to which the present disclosure belongs should understand that they can design or modify other processes and structures based on the embodiments of the present disclosure to achieve the same purpose and/or advantages as the embodiments introduced herein. Those with ordinary knowledge in the art to which the present disclosure belongs should also understand that such equivalent processes and structures do not deviate from the spirit and scope of the present disclosure, and they can make various changes, substitutions and replacements without violating the spirit and scope of the present disclosure.

10: Pixel package 20: Multi-pixel package 30: Display device 100: Carrier 110: Insulation layer 110t1: First upper surface 110t2: First lower surface 120: Upper conductive layer 122: Row driver 124: Column driver 126: Flexible circuit board 130: Lower conductive layer 140: Display substrate 140t1: First side 140t2: Second side 142: Display area 144: Micro driver 150: Wiring structure 200: Pixel 210: First light emitting unit 210S: First light emitting surface 210W: First side surface 212: Growth substrate 214: N-type semiconductor layer 214c: N-type contact electrode 216: Light emitting Optical layer 218: p-type semiconductor layer 218c: p-type contact electrode 220: second light emitting unit 220S: second light emitting surface 220W: second side surface 230: third light emitting unit 230S: fourth light emitting surface 300: solder 400: barrier structure 410: reflective layer 412: first portion 412t: second upper surface 414: second portion 414t: third upper surface 414o: second maximum opening 420: light absorbing layer 420o: first maximum opening 500: wavelength conversion layer 500S: third light emitting surface 500W: third side surface 600: light-transmitting layer D1: distance D2: distance H1: thickness H2: thickness H3: thickness 1: Angle X: Coordinate axis Y: Coordinate axis Z: Coordinate axis

The disclosed embodiments can be better understood from the following detailed description in conjunction with the attached drawings. It should be noted that, in accordance with standard practice in the industry, various features are not drawn to scale and are used for illustration purposes only. In fact, the sizes of various components can be arbitrarily enlarged or reduced to clearly show the features of the disclosed embodiments. FIG. 1A is a top view of a pixel package according to an embodiment of the present disclosure. FIG. 1B is a top view of a multi-pixel package according to another embodiment of the present disclosure. FIG. 2 is a cross-sectional view of a pixel package according to an embodiment of the present disclosure. FIG. 3A is an enlarged view of the dotted line portion of FIG. 2 according to an embodiment of the present disclosure. FIG. 3B is an enlarged view of the dotted line portion of FIG. 2 according to another embodiment of the present disclosure. FIG. 4 is a top view of a display device according to another embodiment of the present disclosure. FIG. 5 is an enlarged cross-sectional view of the dotted line portion of FIG. 4 according to another embodiment of the present disclosure.

100: Carrier board

110: Insulation layer

110t1: First upper surface

110t2: first lower surface

120: Upper conductive layer

130: Lower conductive layer

210: First light-emitting unit

210S: First light-emitting surface

210W: First side surface

214c: n-type contact electrode

218c: p-type contact electrode

220: Second light-emitting unit

220S: Second light-emitting surface

220W: Second side surface

230: The third light-emitting unit

230S: Fourth light-emitting surface

300:Solder

400: retaining wall structure

410:Reflective layer

412: Part 1

412t: Second upper surface

414: Part 2

414t: The third upper surface

420: light-absorbing layer

500: Wavelength conversion layer

500S: The third light-emitting surface

500W: Third side surface

600: light-transmitting layer

Y: coordinate axis

Z: coordinate axis

Claims (8)

A pixel package includes: a carrier having a first upper surface; a pixel disposed on the first upper surface, including: a first light emitting unit having a first light emitting surface and a first side surface; a second light emitting unit having a second light emitting surface and a second side surface, the second side surface facing the first side surface; and a wavelength conversion layer disposed on the second light emitting surface and having a third light emitting surface and a third side surface; a reflective layer having a first portion and a second portion, the reflective layer being disposed between the first side surface and the second side surface, wherein the second portion is located on the first portion and has a third upper surface; and A light absorbing layer is disposed on the third upper surface of the second portion; wherein the height of the third upper surface of the second portion is between the second light emitting surface and the third light emitting surface, wherein the thickness ratio of the light absorbing layer to the second portion measured from a direction perpendicular to the first upper surface is greater than 0 and less than or equal to 1/5; wherein the pixel package has at least one of the following characteristics: (a) the thickness of the second portion is in the range of 5μm to 20μm, and the thickness of the light absorbing layer is in the range of 0.1μm to 1μm; and (b) for light from the first light emitting unit, the reflectivity of the first portion is greater than the reflectivity of the second portion. The pixel package as described in claim 1, wherein the third light-emitting surface is a concave arc. The pixel package as described in claim 1, wherein, in a cross-sectional view, the light absorbing layer has a first maximum opening on the first light emitting unit, and the width of the first maximum opening is greater than the width of the first light emitting surface. The pixel package as described in claim 3, wherein, in the cross-sectional view, the second portion has a second maximum opening on the first light-emitting unit, and the angle between the side wall of the second portion in the second maximum opening and the first light-emitting surface is a blunt angle. A pixel package as described in claim 3, wherein, in the cross-sectional view, the second portion has a second maximum opening on the first light-emitting unit, and the width of the second maximum opening is smaller than the width of the first maximum opening. The pixel package as described in claim 1, wherein the first light-emitting unit and the second light-emitting unit are sub-millimeter light-emitting diodes. A display device comprises: a display substrate having a first side and a second side opposite to each other; a pixel located on the first side of the display substrate, comprising: a first light emitting unit having a first light emitting surface and a first side surface; a second light emitting unit having a second light emitting surface and a second side surface, and the second side surface and the first side surface are opposite to each other; and a wavelength conversion layer arranged on the second light emitting surface and having a third light emitting surface and a third side surface; a reflective layer arranged on the first side of the display substrate, having a first part and a second part, the reflective layer being arranged between the first side surface and the second side surface, wherein the second part is located between the first side surface and the second side surface. The first part has a third upper surface; and a light absorbing layer is disposed on the third upper surface of the second part; wherein the height of the third upper surface of the second part is between the second light emitting surface and the third light emitting surface, wherein the thickness ratio of the light absorbing layer to the second part measured from a direction perpendicular to the first upper surface is greater than 0 and less than or equal to 1/5; wherein the display device has at least one of the following characteristics: (a) the thickness of the second part is in the range of 5μm to 20μm, and the thickness of the light absorbing layer is in the range of 0.1m to 1μm; and (b) for light from the first light emitting unit, the reflectivity of the first part is greater than the reflectivity of the second part. The display device as described in claim 7 further includes a micro-driver, and the first light-emitting unit and the second light-emitting unit in the pixel are electrically connected to the micro-driver through the display substrate.