TWI838865B - Light-emitting diode device - Google Patents

Abstract

A light-emitting diode device is provided. The light-emitting diode device includes a pixel structure including a first light-emitting diode chip, a second light-emitting diode chip, a third light-emitting diode chip, a passivation layer, a first circuit layer, a second circuit layer, a third circuit layer and a fourth circuit layer. The first light-emitting diode chip and the second light-emitting diode chip are positioned on a top surface of the third light-emitting diode chip, which is opposite to a light emitting surface of the third light-emitting diode chip. A first vertical projection of the first light-emitting diode chip on the top surface and a second vertical projection of the second light-emitting diode chip on the top surface do not overlap each other. A first bonding surface of the first circuit layer and a second first bonding surface of the second circuit layer corresponding to openings of the passivation layer are positioned overlapping the first vertical projection and separated from the second vertical projection. A third bonding surface of the third circuit layer and a fourth bonding surface of the fourth circuit layer corresponding to openings of the passivation layer are positioned overlapping the second vertical projection and separated from the first vertical projection.

Description

LED Device

The present disclosure relates to a light emitting diode device, and more particularly to a pixel structure of a light emitting diode device.

Due to the low power consumption of LEDs, light-emitting diode (LED) displays have become the mainstream in the display technology field. However, during the LED display process, the pixel structure composed of red, green and blue primary color LEDs has a high aspect ratio because the thickness and size of the LED components cannot be further reduced, which increases the complexity of the LED bonding process and wiring process, making it difficult for the existing LED pixel structure to achieve the goals of small pitch, large luminous area, high process yield and low cost.

Therefore, there is still a need to further improve the pixel structure of the light-emitting diode to manufacture a display device that meets product requirements.

Some embodiments of the present disclosure provide a light emitting diode device, which includes a pixel structure, wherein the pixel structure includes a first light emitting diode die, a second light emitting diode die, a third light emitting diode die, a protection layer, a first circuit layer, a second circuit layer, a third circuit layer and a fourth circuit layer. The third LED crystal has a light emitting surface and a top surface facing each other, wherein the first LED crystal and the second LED crystal are arranged side by side on the top surface, the first LED crystal has a first vertical projection on the top surface, the second LED crystal has a second vertical projection on the top surface, and the first vertical projection and the second vertical projection do not overlap each other; the protective layer covers the first LED crystal, the second LED crystal and the third LED crystal; the first circuit layer, the second circuit layer, the third circuit layer and the fourth circuit layer separated from each other The layer is located between the third light-emitting diode crystal grain and the protective layer, and the protective layer has a plurality of openings, and the openings correspond to the first bonding surface of the first circuit layer, the second bonding surface of the second circuit layer, the third bonding surface of the third circuit layer, and the fourth bonding surface of the fourth circuit layer, wherein the vertical projections of the first bonding surface and the second bonding surface on the top surface overlap with the first vertical projection respectively, and are both separated from the second vertical projection, and the vertical projections of the third bonding surface and the fourth bonding surface on the top surface overlap with the second vertical projection respectively, and are both separated from the first vertical projection.

The present disclosure is described more fully below with reference to the drawings of the embodiments of the present invention. However, the present disclosure may be implemented in various different embodiments and should not be limited to the embodiments described herein. The thickness of layers and regions in the drawings may be exaggerated for clarity, and the same or similar reference numbers in the drawings represent the same or similar elements.

The disclosed embodiment provides a light emitting diode device. The light emitting diode device stacks two small or micro light emitting diode dies side by side on the top surface of a small or micro light emitting diode die to form a single pixel structure, and is configured with a circuit layer and four joint surfaces (including an anode joint surface and a common cathode joint surface of each of the three light emitting diode dies) so that two of the anode joint surfaces are located above one of the light emitting diode dies stacked side by side, another of the anode joint surfaces and the common cathode joint surface are located above another of the light emitting diode dies stacked side by side, and a light emitting surface of the light emitting diode device is located on the opposite side of the top surface of the lower light emitting diode die. The LED device of the disclosed embodiment can further reduce the volume of pixel structure, simplify the manufacturing process, increase the light-emitting area and reduce the cost. Among them, the small LED chip has a native substrate, while the micro LED chip does not have a native substrate.

FIG. 1 is a three-dimensional schematic diagram of a light-emitting diode device 500 according to some embodiments of the present disclosure. FIG. 2 is a top view schematic diagram of a light-emitting diode device 500 according to some embodiments of the present disclosure. FIG. 3A is a cross-sectional schematic diagram of a pixel structure 550a of the light-emitting diode device 500 according to some embodiments of the present disclosure shown in FIG. 2 along the tangent line X-X'. The light-emitting diode device 500 includes a pixel structure 550 (including the pixel structures 550a and 550b of FIGS. 3A and 3B), and the pixel structure 550 includes a first light-emitting diode die 200, a second light-emitting diode die 300, a third light-emitting diode die 400, and a protective layer 424. For the convenience of explanation, FIG. 1 only shows the first light emitting diode die 200 , the second light emitting diode die 300 and the third light emitting diode die 400 , and the protection layer 424 and other components can be seen in the cross-sectional schematic diagram of FIG. 3A .

As shown in FIG. 3A, the third LED die 400 has a light emitting surface 401 and a top surface 403 facing each other, and the first LED die 200 and the second LED die 300 are arranged side by side on the top surface 403 of the third LED die 400. As shown in FIG. 2, the first LED die 200 has a first vertical projection 200A on the top surface 403 of the third LED die 400, and the second LED die 300 has a second vertical projection 300A on the top surface 403 of the third LED die 400. The first vertical projection 200A and the second vertical projection 300A do not overlap each other.

As shown in FIG. 3A , the first LED grain 200 includes a first electrode 210 and a second electrode 212 away from the top surface 403 of the third LED grain 400, the second LED grain 300 includes a first electrode 310 and a second electrode 312 away from the top surface 403 of the third LED grain 400, and the third LED grain 400 includes a first electrode 410 and a second electrode 412 away from the light emitting surface 401. In some embodiments, the first electrodes 210, 310, and 410 have the same polarity and are opposite to the polarity of the second electrodes 212, 312, and 412. In some embodiments, the first electrode 210, 310, 410 and the second electrode 212, 312, 412 include a conductive material such as chromium (Cr), aluminum (Al), nickel (Ni), gold (Au), platinum (Pt), tin (Sn), copper (Cu), or a combination thereof, and can be formed by a coating process such as evaporation or electroplating and a subsequent patterning process.

In addition, the first LED grain 200 includes an insulating layer 206 covering its sidewalls 205 and a portion of the top surface 203 , the second LED grain 300 includes an insulating layer 306 covering its sidewalls 305 and a portion of the top surface 303 , and the third LED grain 400 includes an insulating layer 406 covering its sidewalls 405 and a portion of the top surface 403 . In some embodiments, the insulating layers 206, 306 _, 406 include insulating materials with good step coverage such as silicon dioxide ( _SiO2 ), aluminum oxide ( _Al2O3 ), titanium dioxide ( _TiO2 ), etc., and can be formed by deposition processes such as chemical vapor deposition (CVD) and atomic layer deposition (ALD). In some embodiments, the insulating layers 206, 306, 406 include insulating materials with low dielectric constant and good step coverage, such as polyimide (PI), epoxy, and benzocyclobutene (BCB), and can be formed by, for example, spin coating, spray coating, or other suitable coating processes.

As shown in FIG. 2 , the first light-emitting diode die 200 has a first top-view area (the same shape and size as the first vertical projection 200A), the second light-emitting diode die 300 has a second top-view area (the same shape and size as the second vertical projection 300A), and the third light-emitting diode die has a third top-view area 400A. In some embodiments, the first top-view area of the first light-emitting diode die 200 is the same as or different from the second top-view area of the second light-emitting diode die 300. In some embodiments, the sum of the first top-view area and the second top-view area is smaller than the third top-view area 400A.

As shown in FIG. 3A , the light emitting surfaces (not shown) of the first light emitting diode die 200 and the second light emitting diode die 300 are both oriented toward the light emitting surface 401 of the third light emitting diode die 400, so that the color light emitted by the first light emitting diode die 200 and the second light emitting diode die 300 is mixed with the color light emitted by the third light emitting diode die 400. In some embodiments, the first light emitting diode die 200, the second light emitting diode die 300, and the third light emitting diode die 400 can emit different color lights (e.g., red light R, green light G, blue light B). And for example, the first LED crystal grain 200 can emit a first color light, the second LED crystal grain 300 can emit a second color light, and the third LED crystal grain 400 can emit a third color light, and the first color light, the second color light, and the third color light have different wavelength ranges. For example, as shown in FIG. 3A, when the first color light is red light (R), the second color light is blue light (B), and the third color light is green light (G), the wavelength range of the third color light is between the wavelength range of the first color light and the wavelength range of the second color light. For example, when the first color light is red light (R), the second color light is green light (G), and the third color light is blue light (B), the wavelength range of the second color light is between the wavelength range of the first color light and the wavelength range of the third color light.

In some embodiments, the first LED die 200, the second LED die 300 and the third LED die 400 include small LED die, micro LED die or other suitable LED die. For example, the first LED die 200 and the second LED die 300 may be micro LED die, and the third LED die 400 may be a small LED die. As in the embodiment shown in FIG. 3A, the first LED die 200 and the second LED die 300 do not include a native substrate, and the third LED die 400 includes a native substrate 402 close to the light emitting surface 401. For another example, the first LED die 200, the second LED die 300 and the third LED die 400 may all be micro LED die. Thus, in other embodiments, the first LED die 200, the second LED die 300 and the third LED die 400 do not include a native substrate.

As shown in FIG. 3A , the pixel structure 550a of the LED device 500 further includes a transparent bonding layer 414. The transparent bonding layer 414 is sandwiched between the first LED die 200, the second LED die 300, and the third LED die 400, and covers the insulating layer 406. In some embodiments, the transparent bonding layer 414 includes benzocyclobutene (BCB), SU-8 epoxy, silicone, epoxy, spin-on glass (SOG), or a combination thereof, and can be formed by, for example, spin coating or other suitable coating processes and subsequent patterning processes.

As shown in FIGS. 3A and 3B, the pixel structure 550 of the LED device 500 further includes a protective layer 424 covering the first LED die 200, the second LED die 300, and the third LED die 400. In some embodiments, the protective layer 424 includes polyimide (PI), benzocyclobutene (BCB), parylene, polynaphthalenes, fluorocarbons, acrylates, or a combination thereof, and the protective layer 424 can be formed by coating or other suitable processes and subsequent patterning processes.

As shown in FIGS. 2 and 3A, the pixel structure 550a of the LED device 500 further includes a first circuit layer 502, a second circuit layer 504, a third circuit layer 506, and a fourth circuit layer 508, which are separated from each other and are located between the third LED die 400 and the protective layer 424. In some embodiments, the first circuit layer 502 and the second circuit layer 504 are respectively disposed on the top surface 203 of the first LED die 200 and are away from the third LED die 400, so that the first LED die 200 is sandwiched between the first circuit layer 502, the second circuit layer 504, and the third LED die 400. The third circuit layer 506 and the fourth circuit layer 508 are respectively disposed on the top surface 303 of the second light-emitting diode die 300 and are far away from the third light-emitting diode die 400, so that the second light-emitting diode die 300 is sandwiched between the third circuit layer 506, the fourth circuit layer 508 and the second light-emitting diode die 300. In addition, the second circuit layer 504 can extend to cover the top surface 403 of the second light-emitting diode die 300, and the fourth circuit layer 508 can extend to cover the top surface 403 of the third light-emitting diode die 400 and be electrically insulated from the second light-emitting diode die 300.

As shown in FIG. 3A , the second circuit layer 504 electrically connects the first electrodes 210, 310, 410 of the first LED die 200, the second LED die 300, and the third LED die 400, while the first circuit layer 502, the third circuit layer 506, and the fourth circuit layer 508 electrically connect the second electrodes 212, 312, 412 of the first LED die 200, the second LED die 300, and the third LED die 400, respectively. In some embodiments, the second circuit layer 504 electrically connects the first electrode 210 of the first light-emitting diode die 200, the first electrode 310 of the second light-emitting diode die 300, and the first electrode 410 of the third light-emitting diode die 400 having the same polarity at the same time, so that the first electrode 210 of the first light-emitting diode die 200, the first electrode 310 of the second light-emitting diode die 300, and the first electrode 410 of the third light-emitting diode die 400 are electrically connected to each other (when the first electrode is a cathode, the second circuit layer 504 is regarded as a common cathode circuit layer). Furthermore, the second electrode 212 of the first LED die 200, the second electrode 312 of the second LED die 300, and the second electrode 412 of the third LED die 400 having the same polarity are respectively electrically connected to the first circuit layer 502, the third circuit layer 506, and the fourth circuit layer 508. In some embodiments, the first circuit layer 502, the third circuit layer 506, and the fourth circuit layer 508 include conductive materials such as chromium (Cr), aluminum (Al), nickel (Ni), gold (Au), platinum (Pt), tin (Sn), copper (Cu), or a combination thereof, and can be formed by a plating process such as evaporation or electroplating and a subsequent patterning process.

The protection layer 424 has a plurality of openings (not shown), which are respectively located on the first bonding surface 502T of the first circuit layer 502, the second bonding surface 504T of the second circuit layer 504, the third bonding surface 506T of the third circuit layer 506, and the fourth bonding surface 508T of the fourth circuit layer 508. As shown in FIG. 2 , vertical projections 502TA and 504TA of the first joint surface 502T and the second joint surface 504T on the top surface 403 of the third LED die 400 overlap with the first vertical projection 200A, respectively, and are both separated from the second vertical projection 300A. Vertical projections 506TA and 508TA of the third joint surface 506T and the fourth joint surface 508T on the top surface 403 of the third LED die 400 overlap with the second vertical projection 300A, respectively, and are both separated from the first vertical projection 200A. In some embodiments, the first bonding surface 502T, the second bonding surface 504T, the third bonding surface 506T, and the fourth bonding surface 508T may be the bonding surfaces of the first circuit layer 502, the third circuit layer 506, and the fourth circuit layer 508 exposed from the opening of the protection layer 424, and may also include metal pads (not shown) formed on the first bonding surface 502T, the second bonding surface 504T, the third bonding surface 506T, and the fourth bonding surface 508T. In some embodiments, the first bonding surface 502T, the second bonding surface 504T, the third bonding surface 506T, and the fourth bonding surface 508T are substantially coplanar.

FIG. 3B is a cross-sectional schematic diagram of the pixel structure 550b of the LED device 500 of some embodiments of the present disclosure along the XX' tangent line shown in FIG. 2, and the same or similar element symbols as those in FIGS. 1, 2, and 3A represent the same or similar elements. As shown in FIG. 3B, the difference between the pixel structure 550b of the LED device 500 and the pixel structure 550a is that the pixel structure 550b further includes a distributed Bragg reflector 418 to increase the light emitting efficiency of the LED device 500. The distributed Bragg reflector 418 can be sandwiched between the protective layer 424 and the first LED die 200, the second LED die 300, and the third LED die 400. In some embodiments, the distributed Bragg reflector conformally covers the sidewall 205 of the first light emitting diode die 200, the sidewall 305 of the second light emitting diode die 300, and the sidewall 405 of the third light emitting diode die 400. In addition, the distributed Bragg reflector 418 covers the portion of the top surface 203 of the first light emitting diode die 200 not covered by the first electrode 210 and the second electrode 212, and the portion of the top surface 303 of the second light emitting diode die 300 not covered by the first electrode 310 and the second electrode 312. In addition, the DBR 418 contacts the first circuit layer 502, the second circuit layer 504, the third circuit layer 506, and the fourth circuit layer 508. In some embodiments, the DBR 418 includes stacked films of two or more homogeneous or heterogeneous materials having different refractive indices. For example, the DBR 418 may be formed by alternate stacking of SiO ₂ and TiO ₂ , alternate stacking of SiO ₂ / Al ₂ O ₃ / TiO ₂ , or alternate stacking of TiO ₂ / SiO ₂ / Ta ₂ O ₅ . In some embodiments, the DBR 418 is formed by a deposition process such as evaporation, atomic layer deposition (ALD), metal organic vapor chemical deposition (MOCVD), and a subsequent patterning process.

The following describes a method for forming the LED device 500. FIGS. 4A, 5A, 6A, and 7A are top-view schematic diagrams of the LED device 500 of some embodiments of the present disclosure as shown in FIG. 1 at different stages. FIGS. 4B, 5B, and 6B are cross-sectional schematic diagrams along the A-A’ tangent line of FIGS. 4A, 5A, and 6A, respectively, showing cross-sectional schematic diagrams of the LED device 500 of some embodiments of the present disclosure as shown in FIG. 1 at different stages. FIG. 7B is an enlarged schematic diagram of the pixel region 700 of FIG. 7A, which shows the configuration of the first LED grain 200, the second LED grain 300, and the third LED grain 400 in the pixel structure 550 in the intermediate step of forming the LED device 500 of some embodiments of the present disclosure. FIG. 7C is a schematic cross-sectional view along the line X-X' of FIG. 7B, showing a schematic cross-sectional view of the LED device 500 of some embodiments of the present disclosure as shown in FIG. 1 at different stages. Component symbols identical or similar to those in FIGS. 1, 2, 3A, and 3B represent identical or similar components. For the sake of convenience, FIGS. 4A, 5A, 6A and 7A only show the first light-emitting diode die 200, the second light-emitting diode die 300 and the third light-emitting diode die 400, and the remaining components (including the carriers 250, 350, the native substrate 402, the first electrodes 210, 310, 410, the second electrodes 212, 312, 412, the transfer devices 252, 352, the insulating layer 406 and the transparent bonding layer 414, etc.) can be seen in the cross-sectional schematic diagrams of FIGS. 4B, 5B, 6B and 7C.

Please refer to Figures 4A, 4B, 5A, 5B, 6A, and 6B, which respectively provide a plurality of first LED grains 200 arranged in an array on a carrier 250, a plurality of second LED grains 300 arranged in an array on a carrier 350, and a plurality of third LED grains 400 grown in an array on a native substrate 402. In some embodiments, the spacing between the first LED grains 200, the spacing between the second LED grains 300, and the spacing between the third LED grains 400 can be the same or different.

Next, the transfer devices 252 and 352 may be used to perform a mass transfer process such as stamp transfer to transfer the selected first LED die 200 and second LED die 300 to the corresponding position of the third LED die 400 . As shown in FIGS. 4A, 4B, 5A, and 5B, downward pressure is applied to the transfer devices 252 and 352 (as indicated by the downward arrows in FIGS. 4B and 5B), and the transfer heads 254 and 354 (e.g., polydimethylsiloxane (PDMS) transfer heads) of the transfer devices 252 and 352 are used to selectively adsorb any number of first LED chips 200 and second LED chips 300 located on the carriers 250 and 350, so as to transfer them to the corresponding positions of the third LED chips 400, and contact the transparent bonding layer 414 to complete the subsequent fixation. For example, the first LED die 200 and the second LED die 300 can be selectively (e.g., every other, every other, or other selective manner) adsorbed and transferred to the top surface 403 of the third LED die 400 according to the spacing of the third LED die 400 array and the corresponding positions of the first LED die 200 and the second LED die 300 arranged on the third LED die 400, so that in each pixel area 700, one first LED die 200 and one second LED die 300 are arranged side by side on one third LED die 400, as shown in FIGS. 7A, 7B, and 7C.

Next, as shown in FIG. 8 , a deposition process and a subsequent patterning process are performed to form a first circuit layer 502, a second circuit layer 504, a third circuit layer 506 and a fourth circuit layer 508 separated from each other on the first LED die 200, the second LED die 300 and the third LED die 400. The first circuit layer 502 covers a portion of the top surface 203 of the first LED die 200 and is electrically connected to the second electrode 212 of the first LED die 200. The second circuit layer 504 extends from a portion of the top surface 203 and the side wall 205 of the first LED die 200 to cover a portion of the top surface 403 of the third LED die 400 and a portion of the top surface 303 and the side wall 305 of the second LED die 300 and electrically connects the first electrode 210 of the first LED die 200, the first electrode 310 of the second LED die 300 and the first electrode 410 of the third LED die 400. The third circuit layer 506 electrically connects the second electrode 312 of the second LED die 300. The fourth circuit layer 508 is electrically connected to the second electrode 412 of the third LED die 400 and extends to cover a portion of the top surface 403 of the third LED die 400 .

Next, as shown in FIG. 3A , a coating process and a subsequent patterning process are performed to form a protection layer 424 covering the first light-emitting diode die 200, the second light-emitting diode die 300, and the third light-emitting diode die 400. The protection layer 424 covers a portion of the first circuit layer 502, the second circuit layer 504, the third circuit layer 506, and the fourth circuit layer 508, and has a plurality of openings (not shown) to define the positions of the first bonding surface 502T of the first circuit layer 502, the second bonding surface 504T of the second circuit layer 504, the third bonding surface 506T of the third circuit layer 506, and the fourth bonding surface 508T of the fourth circuit layer 508. After the above-mentioned manufacturing process, an array of light-emitting diode devices 500 including pixel structures 550a according to some embodiments of the present disclosure is formed.

In some embodiments of the present disclosure, after performing the process similar to that shown in FIGS. 7A-7C , a deposition process and a subsequent patterning process are performed as shown in FIG. 3B to form a distributed Bragg reflector 418 on the first LED die 200 , the second LED die 300 , and the third LED die 400 . The distributed Bragg reflector 418 extends from the sidewall 405 of the third LED die 400 to cover the sidewall 205 and a portion of the top surface 203 of the first LED die 200, and the sidewall 305 and a portion of the top surface 303 of the second LED die 300, so that the first electrode 210 and the second electrode 212 of the first LED die 200 and the first electrode 310 and the second electrode 212 of the second LED die 300 are exposed from the distributed Bragg reflector 418. In some embodiments, the distributed Bragg reflector 418 may be formed before forming the first wiring layer 502, the second wiring layer 504, the third wiring layer 506, and the fourth wiring layer 508. In some other embodiments, the DBR 418 may be formed after forming the first circuit layer 502, the second circuit layer 504, the third circuit layer 506 and the fourth circuit layer 508. After the above processes, an array of LED devices 500 including pixel structures 550b according to some embodiments of the present disclosure is formed.

Figures 9A and 9B are schematic top views of a pixel structure 550a1 of a light-emitting diode device 500 according to some embodiments of the present disclosure. Figure 9A shows the configuration of the first light-emitting diode die 200, the second light-emitting diode die 300, and the third light-emitting diode die 400 in the pixel structure 550a1 and the first circuit layer 502, the second circuit layer 504, the third circuit layer 506, and the fourth circuit layer 508. Figure 9B shows the configuration of the first junction surface 502T of the first circuit layer 502, the second junction surface 504T of the second circuit layer 504, the third junction surface 506T of the third circuit layer 506, and the fourth junction surface 508T of the fourth circuit layer 508 in the pixel structure 550a1 and the protective layer 424.

As shown in FIG. 9A , in some embodiments, the first circuit layer 502 electrically connected to the second electrode 212 and the second circuit layer 504 electrically connected to the first electrodes 210, 310, 410 are respectively disposed on the top surface 203 of the first LED die 200 and away from the third LED die 400. Furthermore, the second circuit layer 504 extends to cover the top surface 303 of the second LED die 300 and the top surface 403 of the third LED die 400. The third circuit layer 506 electrically connected to the second electrode 312 and the fourth circuit layer 508 electrically connected to the second electrode 412 are respectively disposed on the top surface 303 of the second light-emitting diode die 300 and away from the third light-emitting diode die 400. In addition, the fourth circuit layer 508 extends to cover the top surface 403 of the third light-emitting diode die 400.

As shown in FIG. 9B , in some embodiments, the vertical projections 502TA and 504TA of the first joint surface 502T and the second joint surface 504T corresponding to the opening of the protective layer 424 are completely located in the first vertical projection 200A, and the vertical projections 506TA and 508TA of the third joint surface 506T and the fourth joint surface 508T corresponding to the opening of the protective layer 424 are completely located in the second vertical projection 300A. In addition, the first joint surface 502T, the second joint surface 504T, the third joint surface 506T and the fourth joint surface 508T are respectively close to the four corners of the pixel structure 550a1.

In some embodiments, since the first conductivity type semiconductor layer 404-1 of the semiconductor epitaxial stack structure 404 (refer to FIG. 3A , including the first conductivity type semiconductor layer, the second conductivity type semiconductor layer and the light emitting layer (not shown)) of the third light emitting diode die 400 is exposed from the sidewall 405, the common electrode line layer 504 (for example, the second line layer of FIG. 9A ) can be changed. The first electrode 210 of the first LED die 200 and the first electrode 310 of the second LED die 300 are electrically connected to the first conductive type semiconductor layer 404-1 of the third LED die 400 through different circuit layers, instead of being electrically connected to the first electrode 410 of the third LED die 400. FIGS. 10A and 10B are schematic top views of a pixel structure 550a2 of a LED device 500 according to some embodiments of the present disclosure. FIG. 10A shows the arrangement of the first light-emitting diode die 200, the second light-emitting diode die 300, and the third light-emitting diode die 400 and the first circuit layer 502, the second circuit layer 504a1, the third circuit layer 506, the fourth circuit layer 508, and the fifth circuit layer 504a2 in the pixel structure 550a2. FIG. 10B shows the arrangement of the first junction surface 502T of the first circuit layer 502, the second junction surface 504T of the second circuit layer 504a1, the third junction surface 506T of the third circuit layer 506, and the fourth junction surface 508T of the fourth circuit layer 508 in the pixel structure 550a2, and the protective layer 424. The same or similar element symbols in the figure as those in FIGS. 9A and 9B represent the same or similar elements. As shown in FIG. 10A , the difference between the pixel structure 550a2 of the LED device 500 and the pixel structure 550a1 is that the pixel structure 550a2 uses the second circuit layer 504a1 and the fifth circuit layer 504a2 to electrically connect the first electrode 210 of the first LED die 200 and the first electrode 310 of the second LED die 300 to the first conductive type semiconductor layer 404-1 of the semiconductor epitaxial stack structure 404 (please refer to FIG. 3A , which includes a first conductive type semiconductor layer, a second conductive type semiconductor layer and a light-emitting layer (not shown)) of the third LED die 400. In some embodiments, the fifth circuit layer 504a2 is disposed on the top surface 303 of the second LED die 300 and extends to cover the side surface 305 of the second LED die 300 and the third LED die 400. In some embodiments, the fifth circuit layer 504a2 electrically connects the first electrode 310 of the second LED die 300 and the first conductivity type semiconductor layer 404-1 of the third LED die 400. The second circuit layer 504a1 extends to the side surface 205 of the first light-emitting diode die 200 and the third light-emitting diode die 400, and electrically connects the first electrode 210 of the first light-emitting diode die 200 and the first conductive type semiconductor layer 404-1 of the third light-emitting diode die 400. In addition, the second bonding surface 504T of the pixel structure 550a2 is located on the second circuit layer 504a1. Therefore, as shown in FIG. 10B, the first bonding surface 502T, the second bonding surface 504T, the third bonding surface 506T and the fourth bonding surface 508T are still close to the four corners of the pixel structure 550a2.

In some embodiments, the positions of the four joint surfaces of the LED device 500 can be changed accordingly according to the positions of the first electrode and the second electrode of the LED die. FIGS. 11A and 11B are top view schematic diagrams of the pixel structure 550a3 of the LED device 500 according to some embodiments of the present disclosure. FIG. 11A shows the configuration of the first LED die 200, the second LED die 300, and the third LED die 400 and the first circuit layer 502, the second circuit layer 504b, the third circuit layer 506, and the fourth circuit layer 508a in the pixel structure 550a3. FIG. 11B shows the arrangement of the first bonding surface 502T of the first circuit layer 502, the second bonding surface 504T of the second circuit layer 504b, the third bonding surface 506T of the third circuit layer 506, and the fourth bonding surface 508T of the fourth circuit layer 508a and the protective layer 424 in the pixel structure 550a3. Component symbols identical or similar to those in FIGS. 9A, 9B, 10A, and 10B represent identical or similar components. As shown in FIG. 11A , the pixel structure 550a3 of the LED device 500 is different from the pixel structure 550a1 in that the first electrode 310 of the second LED grain 300 of the pixel structure 550a3 is arranged side by side with the first electrode 210 of the first LED grain 200 and the first electrode 410 of the third LED grain 400 along a direction 100 (substantially perpendicular to the first LED grain 200 and the long axis direction of the first LED grain 200). Therefore, the second circuit layer 504b of the pixel structure 550a3 extends from the top surface 203 of the first LED die 200 along the direction 100 to cover the top surface 403 of the third LED 400 and the top surface 303 of the second LED die 300. Moreover, in the top view shown in FIG. 11A , the second circuit layer 504b is substantially in the shape of a strip, and the two ends are respectively located at the end portions of the first LED die 200 and the second LED die 300. The third circuit layer 506 of the pixel structure 550a3 is located in the middle portion of the third circuit layer 506. The fourth circuit layer 508a of the pixel structure 550a3 extends from the second LED die 300 along the direction 100 to cover the top surface 403 of the third LED die 400 and the top surface 203 of the first LED die 200. Moreover, in the top view shown in FIG. 11A, the fourth circuit layer 508a is substantially in the shape of a strip, and the two ends are respectively located at the end portions of the first LED die 200 and the second LED die 300. As shown in FIG. 11B, the first bonding surface 502T and the third bonding surface 506T of the pixel structure 550a3 correspond to the middle portions of the first LED die 200 and the second LED die 300, respectively. The second bonding surface 504T and the fourth bonding surface 508T of the pixel structure 550a3 are respectively close to the diagonal corners of the pixel structure 550a3.

In some embodiments, the first LED die 200a and the second LED die 300a of different sizes may be used, and the design of the circuit layer may be combined so that the four different bonding surfaces are close to the four corners of the pixel structure. FIGS. 12A and 12B are top view schematic diagrams of the pixel structure 550a4 of the LED device 500 of some embodiments of the present disclosure. FIG. 12A shows the configuration of the first LED die 200a, the second LED die 300a and the third LED die 400 and the first circuit layer 502, the second circuit layer 504c, the third circuit layer 506 and the fourth circuit layer 508b in the pixel structure 550a4. FIG. 12B shows the arrangement of the first bonding surface 502T of the first circuit layer 502, the second bonding surface 504T of the second circuit layer 504c, the third bonding surface 506T of the third circuit layer 506, and the fourth bonding surface 508T of the fourth circuit layer 508b and the protective layer 424 in the pixel structure 550a4. Component symbols identical or similar to those in FIGS. 9A, 9B, 10A, 10B, 11A, and 10B represent identical or similar components. As shown in FIG. 12A , the difference between the pixel structure 550a4 of the LED device 500 and the pixel structure 550a1 is that the sizes of the first LED die 200a and the second LED die 300a of the pixel structure 550a4 are smaller than the first LED die 200 and the second LED die 300 shown in FIGS. 9A and 9B , respectively. Therefore, the line width of the portion where the second circuit layer 504c is electrically connected to the first electrodes 210, 310, 410 is smaller than the line width near the corner of the pixel structure 550a4. In addition, the line width of the portion where the fourth circuit layer 508b is electrically connected to the second electrode 412 is smaller than the line width near the corner of the pixel structure 550a4. As shown in FIG. 12B, in some embodiments, the vertical projection 502TA of the first joint surface 502T and the fourth joint surface 508T corresponding to the opening of the protective layer 424 is partially located within the first vertical projection 200aA. The vertical projections 506TA and 508TA of the second joint surface 504T and the third joint surface 506T corresponding to the opening of the protective layer 424 are partially located within the second vertical projection 300aA. The first joint surface 502T and the fourth joint surface 508T located within the first vertical projection 200A are coplanar with the second joint surface 504T and the third joint surface 506T located within the second vertical projection 300aA. In addition, the first joint surface 502T, the second joint surface 504T, the third joint surface 506T and the fourth joint surface 508T are still close to the four corners of the pixel structure 550a4, respectively.

FIG. 13, FIG. 14, and FIG. 15 are top views of pixel structures 550b1, 550b2, and 550b3 of the LED device 500 according to some embodiments of the present disclosure. The pixel structures 550b1, 550b2, and 550b3 are different from the pixel structures 550a1, 550a2, and 550a3 in that the pixel structures 550b1, 550b2, and 550b3 further include distributed Bragg reflectors 418a, 418b, and 418c, respectively. As shown in FIG. 13, the distributed Bragg reflector 418a of the pixel structure 550b1 is formed after the first circuit layer 502, the second circuit layer 504, the third circuit layer 506, and the fourth circuit layer 508 are formed. As shown in FIG. 14, the distributed Bragg reflector 418b of the pixel structure 550b2 is formed after forming the first wiring layer 502, the second wiring layer 504a1, the third wiring layer 506, the fourth wiring layer 508, and the fifth wiring layer 504a2. As shown in FIG. 15, the distributed Bragg reflector 418c of the pixel structure 550b3 is formed after forming the first wiring layer 502, the second wiring layer 504b, the third wiring layer 506, and the fourth wiring layer 508a.

FIG. 16 is a schematic top view of a pixel structure 550b4 of a light emitting diode device 500 according to some embodiments of the present disclosure. The difference between the pixel structure 550b4 and the pixel structure 550a4 is that the pixel structure 550b4 further includes a distributed Bragg reflector 418d. As shown in FIG. 16, the distributed Bragg reflector 418d of the pixel structure 550b4 is formed before forming the first wiring layer 502, the second wiring layer 504c, the third wiring layer 506, and the fourth wiring layer 508b.

FIG. 17 is a three-dimensional schematic diagram of an LED device 500a according to some embodiments of the present disclosure, which shows how a pixel structure 550 with a native substrate 402 (FIG. 3A) is bonded to a circuit substrate 600 and a micro-control element 602. In some embodiments, the LED device 500a further includes a circuit substrate 600 and a micro-control element 602 disposed on the circuit substrate 600. For example, the LED pixel structure array in FIG. 7A is subjected to a laser cutting singulation process to separate the plurality of independent pixel structures 550. Next, a pick and place process may be performed, using a pickup head such as a needle to selectively adsorb the independent pixel structure 550 and place it on the circuit substrate 600, and making the first bonding surface 502T, the second bonding surface 504T, the third bonding surface 506T and the fourth bonding surface 508T (FIG. 2) of the pixel structure 550 electrically contact the corresponding pads (not shown) of the circuit substrate 600, so that the micro-control element 602 is electrically connected to the first circuit layer 502, the second circuit layer 504, the third circuit layer 506 and the fourth circuit layer 508 of the pixel structure 550 through the pads and the circuit layer (not shown) of the circuit substrate 600, so as to control different pixel structures 550 respectively.

FIG. 18 is a three-dimensional schematic diagram of an LED device 500b including a circuit substrate 600 and a micro-control element 602 according to some embodiments of the present disclosure, which shows how a pixel structure 550c with the native substrate 402 ( FIG. 3A ) removed is bonded to the circuit substrate 600 and the micro-control element 602. The difference between the LED device 500b and the LED device 500a is that the third LED die of the LED device 500b does not include a native substrate. For example, the LED pixel structure array in FIG. 7A is subjected to a substrate removal process of laser lift-off (LLO) to remove the native substrate 402 of the pixel structure array of the LED device 500b and separate it into a plurality of independent pixel structures 550c, so as to further reduce the size of the pixel structure 550c. Next, a mass transfer process such as stamp transfer can be performed, using, for example, a polydimethylsiloxane (PDMS) transfer head to selectively adsorb an independent pixel structure 550c and set it on the circuit substrate 600, and make the first bonding surface 502T, the second bonding surface 504T, the third bonding surface 506T and the fourth bonding surface 508T (Figure 2) of the pixel structure 550c electrically contact the corresponding pads (not shown) of the circuit substrate 600, so that the micro-control element 602 is electrically connected to the first circuit layer 502, the second circuit layer 504, the third circuit layer 506 and the fourth circuit layer 508 of the pixel structure 550c through the pads and circuit layers (not shown) of the circuit substrate 600, so as to control different pixel structures 550c respectively.

FIG. 19A, FIG. 19B, and FIG. 19C are three-dimensional schematic diagrams and cross-sectional schematic diagrams of a light-emitting diode device 500c according to some embodiments of the present disclosure, which show the bonding method of the pixel structure 550 and the thin film transistor substrate 610. The difference between the light-emitting diode device 500c and the light-emitting diode device 500b is that the pixel structure 550 of the light-emitting diode device 500c is bonded to the thin film transistor substrate 610 to form the light-emitting diode device 500c of, for example, a light-emitting diode display device. In some embodiments, the light-emitting diode device 500 further includes a thin film transistor substrate 610 disposed on the pixel structure 550. As shown in FIGS. 19A and 19B, in some embodiments, after forming an array of pixel structures 550 of a light-emitting diode device 500c, a semiconductor process is performed to form a thin film transistor substrate 610 on the pixel structures 550. The thin film transistor substrate 610 includes a plurality of thin film transistors 612a, 612b, 612c and circuits (not shown) corresponding to each pixel structure 550. The thin film transistors 612a, 612b, 612c and circuits are electrically connected to the first bonding surface 502T of the first wiring layer 502, the second bonding surface 504T of the second wiring layer 504, the third bonding surface 506T of the third wiring layer 506, and the fourth bonding surface 508T of the fourth wiring layer 508 of the corresponding pixel structure 550 (FIGS. 2 and 3A) to control different pixel structures 550 respectively.

As shown in FIGS. 19A and 19C, in some embodiments, the array of pixel structures 550 can be bonded to the prepared thin film transistor substrate 610 to form a light-emitting diode device 500c such as a light-emitting diode display device. The first bonding surface 502T of the first circuit layer 502, the second bonding surface 504T of the second circuit layer 504, the third bonding surface 506T of the third circuit layer 506, and the fourth bonding surface 508T of the fourth circuit layer 508 (FIGS. 2 and 3A) of each pixel structure 550 of the light-emitting diode device 500c are electrically connected to corresponding thin film transistors 612a, 612b, 612c and circuits (not shown) respectively to control different pixel structures 550 respectively.

The disclosed embodiment provides a light emitting diode device. The light emitting diode device stacks two small or micro light emitting diode dies side by side on the top surface of a light emitting diode die to form a single pixel structure, and the circuit layer of each light emitting diode die is configured so that two of the three anode junction surfaces and the common cathode junction surface are located above one of the side-by-side stacked light emitting diode dies, the other anode junction surface and the common cathode junction surface are located above another of the side-by-side stacked light emitting diode dies, and the light emitting surface of the light emitting diode device is located on the opposite side of the top surface of the lower light emitting diode die. In some embodiments, the pixel structure of the LED device can be bonded to a circuit substrate provided with a micro-control element to control different pixel structures separately. In some embodiments, the pixel structure array of the LED device can be bonded to a thin film transistor substrate to form, for example, a LED display device, wherein the thin film transistors of the thin film transistor substrate control different pixel structures separately. The LED device of the disclosed embodiment utilizes a transfer process to stack two micro LED dies side by side on another micro or small LED die, so there is no need to perform a highly complex wafer bonding process and a high aspect ratio circuit process, and the LED dies stacked side by side can also be binned in advance, which can further reduce the size of the pixel structure, simplify the process, improve the yield and reduce the cost. In some embodiments, the LED device of the disclosed embodiment stacks red and blue LED chips side by side on a green LED chip, and the brightness of the pixel structure is controlled by the green LED chip below, which can increase the luminous area and brightness. In some embodiments, it can be a design of three anodes and one common cathode. In some embodiments, the polarity of the cathode and anode of the three LED chips can also be completely reversed to form a design of three cathodes and one common anode.

Although the present disclosure is disclosed in the above embodiments, they are not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention belongs may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present disclosure shall be subject to the scope defined by the attached patent application.

100: direction 200,200a: first LED die 203,303,403: top surface 205,305,405: side wall 206,306,406: insulating layer 210,310,410: first electrode 212,312,412: second electrode 250,350: carrier 252,352: transfer device 300,300a: second LED die 400: third LED die 401: light emitting surface 402: native substrate 404-1: first conductivity type semiconductor layer 414: transparent bonding layer 418,418a,418b,418c,418d: Distributed Bragg reflector 424: Protective layer 200A,200aA: First vertical projection 300A,300aA: Second vertical projection 400A: Third top view area 500,500a,500b,500c: Light-emitting diode device 550,550a,550a1,550a2,550a3,550a4,550b,550b1,550b2,550b3,550b4,550c: Pixel structure 502: First circuit layer 504,504a1,504b,504c: Second circuit layer 506: Third circuit layer 508,508a,508b: fourth circuit layer 504a2: fifth circuit layer 502T: first joint surface 504T: second joint surface 506T: third joint surface 508T: fourth joint surface 502TA,504TA,506TA,508TA: vertical projection 600: circuit substrate 610: thin film transistor substrate 602: micro control element 700: pixel area A-A’,X-X’: tangent line R: red light G: green light B: blue light

FIG. 1 is a three-dimensional schematic diagram of a light-emitting diode device according to some embodiments of the present disclosure. FIG. 2 is a top view schematic diagram of a light-emitting diode device according to some embodiments of the present disclosure. FIG. 3A is a cross-sectional schematic diagram along the X-X’ tangent line of the light-emitting diode device according to some embodiments of the present disclosure shown in FIG. 2. FIG. 3B is a cross-sectional schematic diagram along the X-X’ tangent line of the light-emitting diode device according to some embodiments of the present disclosure shown in FIG. 2. FIG. 4A, 5A, 6A, and 7A are top view schematic diagrams of the light-emitting diode device according to some embodiments of the present disclosure shown in FIG. 1 at different stages of formation. Figures 4B, 5B, and 6B are schematic cross-sectional views along the A-A’ tangent line of Figures 4A, 5A, and 6A, respectively, showing schematic cross-sectional views of the light-emitting diode device of some embodiments of the present disclosure as shown in Figure 1 at different stages. Figure 7B is an enlarged schematic view of Figure 7A, which shows the configuration of the light-emitting diode grains in the pixel structure of the intermediate step of forming the light-emitting diode device of some embodiments of the present disclosure. Figures 7C and 8 are schematic cross-sectional views along the X-X’ tangent line of Figure 7B, showing schematic cross-sectional views of the light-emitting diode device of some embodiments of the present disclosure as shown in Figure 1 at different stages. Figures 9A and 9B are schematic top views of the LED device of some embodiments of the present disclosure, which show the configuration of the LED die, circuit layer, and its junction surface and protective layer in the LED device. Figures 10A and 10B are schematic top views of the LED device of some embodiments of the present disclosure, which show the configuration of the LED die, circuit layer, and its junction surface and protective layer in the LED device. Figures 11A and 11B are schematic top views of the LED device of some embodiments of the present disclosure, which show the configuration of the LED die, circuit layer, and its junction surface and protective layer in the LED device. Figures 12A and 12B are schematic top views of LED devices of some embodiments of the present disclosure, which show the configuration of LED dies, circuit layers, their joint surfaces, and protective layers in the LED devices. Figures 13, 14, 15, and 16 are schematic top views of LED devices of some embodiments of the present disclosure, which show the configuration of LED dies, circuit layers, and distributed Bragg reflectors in the LED devices. Figure 17 is a three-dimensional schematic view of LED devices of some embodiments of the present disclosure, which shows the bonding method of the pixel structure of the LED device with a native substrate and the micro-control element and circuit substrate. FIG. 18 is a three-dimensional schematic diagram of a light-emitting diode device according to some embodiments of the present disclosure, which shows the bonding method of the pixel structure of the light-emitting diode device without a native substrate and the micro-control element and the circuit substrate. FIGS. 19A, 19B, and 19C are three-dimensional schematic diagrams and cross-sectional schematic diagrams of the light-emitting diode device according to some embodiments of the present disclosure, which show the bonding method of the pixel structure of the light-emitting diode device and the thin film transistor substrate.

200: First light-emitting diode grain

403: Top

300: Second light-emitting diode grain

400: The third light-emitting diode grain

424: Protective layer

200A: First vertical projection

300A: Second vertical projection

550a1: Pixel structure

502T: First joint surface

504T: Second joint surface

506T: Third joint surface

508T: Fourth joint surface

502TA,504TA,506TA,508TA: vertical projection

Claims (17)

A light-emitting diode device comprises: A pixel structure, comprising: A first light-emitting diode crystal, having a first top surface; A second light-emitting diode crystal, having a second top surface; A third light-emitting diode crystal, having a light-emitting surface and a third top surface opposite to each other; wherein the first light-emitting diode crystal and the second light-emitting diode crystal are arranged side by side on the third top surface, the first light-emitting diode crystal has a first vertical projection on the third top surface, the second light-emitting diode crystal has a second vertical projection on the third top surface, and the first vertical projection and the second vertical projection do not overlap each other; A protective layer, covering the first light-emitting diode crystal, the second light-emitting diode crystal and the third light-emitting diode crystal; and A first circuit layer, a second circuit layer, a third circuit layer and a fourth circuit layer separated from each other are located between the third light-emitting diode die and the protective layer; wherein the first circuit layer has a first bonding surface, the second circuit layer has a second bonding surface, the third circuit layer has a third bonding surface and the fourth circuit layer has a fourth bonding surface, and the protective layer has a plurality of openings, which correspond to the first bonding surface of the first circuit layer. , the second bonding surface of the second circuit layer, the third bonding surface of the third circuit layer, and the fourth bonding surface of the fourth circuit layer; wherein the vertical projections of the first bonding surface and the second bonding surface on the third top surface overlap with the first vertical projection respectively, and are both separated from the second vertical projection, and the vertical projections of the third bonding surface and the fourth bonding surface on the third top surface overlap with the second vertical projection respectively, and are both separated from the first vertical projection. The LED device of claim 1, wherein the first LED grain has a first electrode, the second LED grain has a first electrode, and the third LED grain has a first electrode; wherein the first electrode of the first LED grain, the first electrode of the second LED grain, and the first electrode of the third LED grain are electrically connected to each other. A light-emitting diode device as claimed in claim 1, wherein the first light-emitting diode grain has a first electrode, the second light-emitting diode grain has a first electrode and the third light-emitting diode grain has a first electrode; wherein the second circuit layer electrically connects the first electrode of the first light-emitting diode grain, the first electrode of the second light-emitting diode grain and the first electrode of the third light-emitting diode grain at the same time; wherein the first electrode of the first light-emitting diode grain, the first electrode of the second light-emitting diode grain and the first electrode of the third light-emitting diode grain have the same polarity. The LED device of claim 1, wherein the first circuit layer and the second circuit layer are respectively disposed on the first top surface of the first LED die away from the third LED die; wherein the third circuit layer and the fourth circuit layer are respectively disposed on the second top surface of the second LED die away from the third LED die. The LED device of claim 1, wherein the second circuit layer extends to cover the second top surface of the second LED die and/or the fourth circuit layer extends to cover the third top surface of the third LED die. The LED device of claim 1, wherein the fourth circuit layer extends to cover the first top surface of the first LED die. A light-emitting diode device as claimed in claim 3, wherein the first light-emitting diode die has a second electrode, the second light-emitting diode die has a second electrode, and the third light-emitting diode die has a second electrode; wherein the second circuit layer and the first circuit layer are electrically connected to the first electrode and the second electrode of the first light-emitting diode die, respectively; wherein the third circuit layer is electrically connected to the second electrode of the second light-emitting diode die; wherein the fourth circuit layer is electrically connected to the second electrode of the third light-emitting diode die and is electrically insulated from the second light-emitting diode die. As in claim 3, the first light-emitting diode device has a side surface, the second light-emitting diode die has a side surface, and the third light-emitting diode die has a first conductive type semiconductor layer, and the light-emitting diode device further includes: A fifth circuit layer is disposed on the second top surface of the second light-emitting diode crystal grain and extends to cover the side surface of the second light-emitting diode crystal grain and the third light-emitting diode crystal grain; wherein the fifth circuit layer electrically connects the first electrode of the second light-emitting diode crystal grain and the first conductive type semiconductor layer of the third light-emitting diode crystal grain; wherein the second circuit layer extends to the side surface of the first light-emitting diode crystal grain and the third light-emitting diode crystal grain, and electrically connects the first electrode of the first light-emitting diode crystal grain and the first conductive type semiconductor layer of the third light-emitting diode crystal grain. The LED device of claim 1 further comprises: A distributed Bragg reflector, sandwiched between the protective layer and the first LED crystal, the second LED crystal and the third LED crystal, the distributed Bragg reflector covers multiple side walls of the first LED crystal, the second LED crystal and the third LED crystal. The LED device of claim 1, wherein the first LED die emits a first color light, the second LED die emits a second color light, and the third LED die emits a third color light, wherein the first color light, the second color light and the third color light have different wavelength ranges respectively. As in claim 10, the light-emitting diode device, wherein the wavelength range of the third color light is between the wavelength range of the first color light and the wavelength range of the second color light. A light-emitting diode device as claimed in claim 10, wherein the wavelength range of the second color light is between the wavelength range of the first color light and the wavelength range of the third color light. The light-emitting diode device of claim 1 further includes: a circuit substrate for providing the pixel structure thereon; and a micro-control element disposed on the circuit substrate and electrically connected to the first circuit layer, the second circuit layer, the third circuit layer and the fourth circuit layer. The light-emitting diode device of claim 1 further includes: A thin film transistor substrate disposed on the pixel structure and electrically connected to the first circuit layer, the second circuit layer, the third circuit layer and the fourth circuit layer. The LED device of claim 1, wherein the first LED die has a first top-view area, the second LED die has a second top-view area, and the third LED die has a third top-view area; wherein the sum of the first top-view area and the second top-view area is smaller than the third top-view area. The LED device of claim 1, wherein the vertical projections of the first joint surface and the second joint surface are completely located within the first vertical projection, and the vertical projections of the third joint surface and the fourth joint surface are completely located within the second vertical projection. The LED device of claim 1, wherein the vertical projection portions of the first joint surface and the second joint surface are located outside the first vertical projection range, and the vertical projection portions of the third joint surface and the fourth joint surface are located outside the second vertical projection range.

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