Display device and method of manufacturing same

Abstract

The invention provides a display device and a manufacturing method of the display device. The display device comprises a control panel, a conductive layer, a first micro light-emitting element and a second micro light-emitting element. The conductive layer is directly connected with the control panel. The conductive layer is divided into a first conductive layer having a first thickness and a second conductive layer having a second thickness. The second thickness is greater than the first thickness. The first micro light-emitting element is disposed on the first conductive layer. The first micro-light-emitting element has a first light-emitting layer. The first light emitting layer emits light of a first color. The second micro light-emitting element is disposed on the second conductive layer. The second micro-light-emitting element has a second light-emitting layer. The second light emitting layer emits light of a second color different from the first color. The projection of the first micro light-emitting element and the projection of the second micro light-emitting element on the control panel are not overlapped.

Description

Technical Field

[0001] The present invention relates to a display device and a manufacturing method thereof. Background Art

[0002] In recent years, displays with pixel sizes reduced to the micron level have become one of the key research directions. Since the pitch between the sub-pixels of a microdisplay has been significantly reduced, when transferring micro light-emitting chips of the three primary colors RGB separately to a complementary metal oxide semiconductor (CMOS) control panel by mass transfer, the yield is easily affected.

[0003] To improve the problem of difficult transfer, known solutions are to transfer a co-semiconductor layer epitaxial structure of a single color (such as blue light) or multiple chips of a single color with a common electrode package. However, although the above two solutions can easily achieve full-surface transfer, quantum dot (QD) materials need to be used separately to achieve full-color display (for example, quantum dots for red and green light). Among them, due to the need for conversion wavelength, the quantum dot material for converting green light has a smaller volume and a larger surface area, which makes it difficult to improve the conversion efficiency of green light and its lifespan is also more easily affected. Summary of the Invention

[0004] The present invention provides a display device that can achieve a single-chip full-color microdisplay without a mass transfer process, which helps to significantly improve the manufacturing yield. In addition, the present invention is not limited to the application of quantum dot color conversion technology and can also be applied to micro light-emitting chips of primary colors. A manufacturing method of the display device of the present invention is also proposed.

[0005] An embodiment of the present invention provides a display device, including a control panel, a plurality of conductive layers, a plurality of first micro light-emitting elements, and a plurality of second micro light-emitting elements. The plurality of conductive layers are directly connected to the control panel respectively. The plurality of conductive layers are divided into a plurality of first conductive layers having a first thickness and a plurality of second conductive layers having a second thickness. The second thickness is greater than the first thickness. The plurality of first micro light-emitting elements are disposed on one of the first conductive layers. The first micro light-emitting element has a first light-emitting layer. The first light-emitting layer emits light of a first color. The plurality of second micro light-emitting elements are disposed on one of the second conductive layers. The second micro light-emitting element has a second light-emitting layer. The second light-emitting layer emits a second color different from the first color. The projections of the first micro light-emitting element and the second micro light-emitting element on the control panel do not overlap with each other.

[0006] An embodiment of the present invention provides a method for manufacturing a display device, including: sequentially stacking a first epitaxial structure layer and a second epitaxial structure layer on a first substrate; etching the second epitaxial structure layer from a first side and etching the first epitaxial structure layer from a second side to form a plurality of first micro-light-emitting elements and a plurality of second micro-light-emitting elements, wherein the emission colors of the plurality of first micro-light-emitting elements are different from those of the plurality of second micro-light-emitting elements; covering a conductive layer on the first micro-light-emitting elements and the second micro-light-emitting elements to connect the first micro-light-emitting elements and the second micro-light-emitting elements to a control panel through the conductive layer, wherein the projections of the plurality of first micro-light-emitting elements and the plurality of second micro-light-emitting elements on the control panel do not overlap; and patterning and etching the conductive layer to expose the control panel, wherein the conductive layer is etched and divided into a plurality of first conductive layers and a plurality of second conductive layers, the plurality of first micro-light-emitting elements are correspondingly disposed on the plurality of first conductive layers, the plurality of second micro-light-emitting elements are correspondingly disposed on the plurality of second conductive layers, and the plurality of first conductive layers and the plurality of second conductive layers are separated from each other on the control panel and are electrically insulated from each other.

[0007] Based on the above, in the display device according to the embodiment of the present invention, since the second thickness of the second conductive layer is greater than the first thickness of the first conductive layer, and the projections of the first micro-light-emitting elements and the second micro-light-emitting elements on the control panel do not overlap with each other, the micro-light-emitting elements with different emission colors are independent of each other and do not overlap. The light-emitting areas within the pixels formed by the micro-light-emitting elements with different emission colors can be freely distributed or redundantly designed, without problems of mutual crosstalk or parasitic capacitance caused by the overlapping of micro-light-emitting elements. In the method for manufacturing a display device according to the embodiment of the present invention, the first micro-light-emitting elements and the second micro-light-emitting elements are formed by stacking and etching, and the first micro-light-emitting elements and the second micro-light-emitting elements finally remaining on the control panel do not overlap. Therefore, in the display device and its manufacturing method according to the embodiment of the present invention, different micro-light-emitting elements with different emission colors can be integrated together without using a mass transfer process, which can greatly improve the manufacturing yield of the display device and reduce the transfer and repair costs. Description of the Drawings

[0008] Figure 1A - Figure 1B is a schematic diagram of a display device according to an embodiment of the present invention;

[0009] Figure 2A - Figure 2B is a schematic diagram of a display device according to another embodiment of the present invention;

[0010] Figure 3A - Figure 3L is a schematic flow chart of a method for manufacturing a display device according to an embodiment of the present invention;

[0011] Figure 4A - Figure 4B is a partial schematic flow chart of a method for manufacturing a display device according to an embodiment of the present invention. Detailed implementation manners

[0012] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals are used in the drawings and the description to refer to the same or like parts.

[0013] Figure 1A - Figure 1B is a schematic diagram of a display device according to an embodiment of the present invention. Please also refer to Figure 1A - Figure 1B , the display device 10a of this embodiment includes a control panel 100, a plurality of conductive layers 110, a plurality of first micro light-emitting elements 120a, a plurality of second micro light-emitting elements 120b, a light reflection layer 130, and an insulating layer 140. The plurality of conductive layers 110 are respectively directly connected to the bonding layer CM of the control panel 100, and the plurality of conductive layers 110 are disposed on the control panel 100 separately from each other and are electrically independent of each other.

[0014] The control panel 100 defines a plurality of pixel regions, and Figure 1A - Figure 1B schematically shows one of the pixel regions, in which a first micro light-emitting element 120a, a second micro light-emitting element 120b, and a second micro light-emitting element 120b' are provided. However, in other embodiments, the pixel region may also include more than four micro light-emitting elements, but the conductive layer 110 has three or less than three thicknesses.

[0015] The plurality of conductive layers 110 are divided into a plurality of first conductive layers 110a having a first thickness t1 and a plurality of second conductive layers 110b having a second thickness t2, and the second thickness t2 is greater than the first thickness t1. The second thickness t2 is greater than the height H1 of the top surface S1 of the first micro light-emitting element 120a relative to the bonding layer CM.

[0016] The first micro light-emitting element 120a includes a first type semiconductor 120a-s1 and a second type semiconductor 120a-s2. The second micro light-emitting element 120b includes a first type semiconductor 120b-s1 and a second type semiconductor 120b-s2. In this embodiment, the first micro light-emitting element 120a may further include a transparent conductive layer 120ai, which is connected between the second type semiconductor 120a-s2 and the first conductive layer 110a. The second micro light-emitting element 120b may further include a transparent conductive layer 120bi, which is connected between the second type semiconductor 120b-s2 and the second conductive layer 110b. The materials of the transparent conductive layers 120ai and 120bi are, for example, indium tin oxide or other transparent conductive materials.

[0017] Please refer to Figure 1B, a plurality of first micro light-emitting elements 120a are respectively disposed on a plurality of first conductive layers 110a, and have a first light-emitting layer 120a-QW to emit light of a first color C1 (e.g., green). A plurality of second micro light-emitting elements 120b are respectively disposed on a plurality of second conductive layers 110b, and have a second light-emitting layer 120b-QW to emit light of a second color C2 different from the first color C1 (e.g., blue). Here, the projections of the plurality of first micro light-emitting elements 120a, the plurality of second micro light-emitting elements 120b, and the plurality of second micro light-emitting elements 120b' on the control panel 100 do not overlap with each other.

[0018] Each first-type semiconductor is located on a side of the first micro light-emitting elements 120a, 120b, 120b' away from the control panel 100, and the surface of each first-type semiconductor may have a roughened structure. Here, each first-type semiconductor is, for example, an N-type semiconductor, and its surface can form a roughened structure by ion bombardment (e.g., plasma formed by argon) or chemical mechanical polishing process (CMP). In addition, the roughening process can also thin the thickness of each first-type semiconductor, so that the ratio of the thickness of each first-type semiconductor to the thickness of the second-type semiconductor can be between 1 and 1.6. However, the present invention is not limited thereto. For different epitaxial processes, the first-type semiconductor may also be a P-type or other semiconductor, and the type of the second-type semiconductor is not limited here either.

[0019] The light reflection layer 130 covers the peripheral side surfaces of the plurality of first micro light-emitting elements 120a, the plurality of second micro light-emitting elements 120b, the plurality of first conductive layers 110a, and the plurality of second conductive layers 110b, and the control panel 100, wherein the plurality of first conductive layers 110a and the plurality of second conductive layers 110b contain light reflection materials. In this embodiment, the light reflection layer 130 is a common electrode layer for the plurality of first micro light-emitting elements 120a and the plurality of second micro light-emitting elements 120b, and is electrically connected to their first-type semiconductors 120a-s1, 120b-s1.

[0020] The insulating layer 140 is a single film layer (e.g., a silicon dioxide film layer), disposed between the light reflection layer 130 and the first micro light-emitting element 120a or the second micro light-emitting element 120b to cover the plurality of first micro light-emitting elements 120a and the plurality of second micro light-emitting elements 120b together, so as to shield the second-type semiconductors 120a-s2, 120b-s2 of the first micro light-emitting element 120a and the second micro light-emitting element 120b from contacting the light reflection layer 130.

[0021] A plurality of bonding layers CM on the surface of the control panel 100 are, for example, metal wiring layers. Each bonding layer CM has a bonding surface CM1 and side wall surfaces CM2 connecting the bonding surface CM1, and the side wall surfaces CM2 are etched surfaces. A plurality of conductive layers 110 are bonded to the plurality of bonding surfaces CM1 to connect the control panel 100. In this embodiment, the circumferential side surfaces of the plurality of conductive layers 110 and the plurality of side wall surfaces CM2 of the plurality of bonding layers CM form a continuous surface. In addition, in this embodiment, the circumferential side surfaces of the plurality of conductive layers 110 and the side wall surfaces CM2 are also etched surfaces.

[0022] In Figure 1B it, after removing the light reflection layer 130 on the central regions of the tops S1, S2, S2' of the first micro light-emitting element 120a and the second micro light-emitting elements 120b, 120b', the display device 10a forms the display device 10b. The display device 10b may additionally include color filters 160a to 160c and a lens layer 190. The color filters 160a to 160c are respectively disposed on the plurality of first micro light-emitting elements 120a and the plurality of second micro light-emitting elements 120b, 120b'. The colors of the color filters 160a, 160b, and 160c (i.e., the colors of the light allowed to pass through) respectively correspond to the light-emitting colors of the first light-emitting layer 120a-QW and the second micro light-emitting elements 120b, 120b', that is, they respectively correspond to the first color C1 (such as green), the second color C2 (such as blue), and the third color C3 (such as red), but are not limited to the examples here.

[0023] Since the second micro light-emitting elements 120b, 120b' of this embodiment have the same second light-emitting layer 120b-QW, the display device 10b may include a color conversion structure 160c-1. The color conversion structure 160c-1 is, for example, a quantum dot color conversion structure, and is disposed on some of the plurality of second micro light-emitting elements 120b'. For example, the second micro light-emitting element 120b' includes an epitaxial structure, the second light-emitting layer 120b-QW is located in the epitaxial structure, and a groove g1 is provided between the top surface S2' far from the control panel 100 and the second light-emitting layer 120b-QW, and the color conversion structure 160c-1 is disposed in the groove g1. That is to say, the color conversion structure 160c-1 can be disposed in the groove g1 formed by the first-type semiconductor 120b-s1 of the second micro light-emitting element 120b' and is closed by the color filter 160c covering the top surface S2'. Thereby, the light of the second color C2 emitted by the second light-emitting layer 120b-QW can be converted into the light of the third color C3 by the color conversion structure 160c-1.

[0024] The lens layer 190 is disposed on each micro light-emitting element to help converge the light passing through the color filter and improve the display effect.

[0025] Figure 2A - Figure 2B It is a schematic diagram of a display device according to another embodiment of the present invention. Figure 2A - Figure 2B Differences from Figure 1A - Figure 1B lie in that the display device 10c further includes a plurality of third micro light-emitting elements 120c. The plurality of third micro light-emitting elements 120c are respectively disposed on a plurality of third conductive layers 110c, and have a third light-emitting layer 120c-QW to emit light of a third color C3 (such as red) different from the first color C1 and the second color C2. That is to say, a first micro light-emitting element 120a, a second micro light-emitting element 120b, and a third micro light-emitting element 120c are provided in the pixel region, and the third micro light-emitting element 120 can directly emit light from the third light-emitting layer 120c-QW without converting the light-emitting color by means of the second micro light-emitting element 120b. In one embodiment, a pixel region may include at least four micro light-emitting elements. That is to say, in the above embodiments, the number of micro light-emitting elements of any color can be greater than one. In addition, the light-emitting areas of the first micro light-emitting element 120a, the second micro light-emitting element 120b, and the third micro light-emitting element 120c may be different. For example, Figure 2A the top surface S3 of the third micro light-emitting element 120c in can have a larger area compared to the top surfaces S1 and S2 of the other two micro light-emitting elements. Thus, when the light-emitting brightness of each micro light-emitting element or the decay curve of the brightness over time is different, the design requirements of the display can be met by adjusting their numbers or sizes.

[0026] The plurality of conductive layers 110 can also be distinguished by a third thickness. For example, the third conductive layer 110c has a third thickness t3 greater than the second thickness t2, and the third thickness t3 can be further greater than the height H2 of the top surface S2 of the second micro light-emitting element 120b relative to the bonding layer CM. The top surface S3 of the third micro light-emitting element 120c has a height H3 relative to the bonding layer CM.

[0027] There is a spacing d between the first micro light-emitting element 120a and the second micro light-emitting element 120b, and between the second micro light-emitting element 120b and the third micro light-emitting element 120c in a direction parallel to the control panel 100. The ratio of the spacing d to the first thickness t1 is, for example, greater than or equal to 0.25, but the present invention is not limited thereto.

[0028] The range of the spacing d can be, for example, from 0.25 μm to 1 μm. The ratio of the spacing d to the height H1 can be, for example, 1:4, 1:8, or 1:16. The ratio of the heights H1, H2, and H3 can be, for example, 2:3:4. In each of the embodiments described herein, the spacing d between all the micro light-emitting elements is the same. However, considering factors such as process margins or yields, there may be various actual values for the spacing d.

[0029] In this embodiment, the third micro light-emitting element 120c may further include a transparent conductive layer 120ci, which is connected between the second-type semiconductor 120c-s2 and the third conductive layer 110c. The material of the transparent conductive layer 120ci is, for example, indium tin oxide or other transparent conductive materials.

[0030] Figure 3A - Figure 3L It is a schematic flow chart of a manufacturing method of a display device according to an embodiment of the present invention. Please refer to Figure 3A - Figure 3L , the manufacturing method of the display device of this embodiment includes the following steps.

[0031] First, please refer to Figure 3A, the first epitaxial structure layers 120a-e and the second epitaxial structure layers 120b-e are sequentially stacked on the first substrate 170. In this embodiment, after stacking the second epitaxial structure layers 120b-e, a third epitaxial structure layer 120c-e can be further stacked on the second epitaxial structure layers 120b-e. Among them, the first substrate 170 is, for example, a substrate made of sapphire material or a substrate made of other materials. The first epitaxial structure layers 120a-e include a first-type semiconductor 120a-s1, a second-type semiconductor 120a-s2, and a first light-emitting layer 120a-QW disposed between the first-type semiconductor 120a-s1 and the second-type semiconductor 120a-s2. The second epitaxial structure layers 120b-e include a first-type semiconductor 120b-s1, a second-type semiconductor 120b-s2, and a second light-emitting layer 120b-QW disposed between the first-type semiconductor 120b-s1 and the second-type semiconductor 120b-s2. The third epitaxial structure layers 120c-e include a first-type semiconductor 120c-s1, a second-type semiconductor 120c-s2, and a third light-emitting layer 120c-QW disposed between the first-type semiconductor 120c-s1 and the second-type semiconductor 120c-s2. In addition, an adhesive layer 150 is used to bond between adjacent epitaxial structure layers and between the epitaxial structure layer and the first substrate 170. In this embodiment, it also includes a transparent conductive layer 120ai on the side of the first epitaxial structure layer 120a-e adjacent to the first substrate 170, a transparent conductive layer 120bi on the side of the second epitaxial structure layer 120b-e adjacent to the first substrate 170, and a transparent conductive layer 120ci on the side of the third epitaxial structure layer 120c-e adjacent to the first substrate 170. Additionally, in this embodiment, after stacking the first epitaxial structure layer 120a-e on the first substrate 170, the first-type semiconductor 120a-s1 can be thinned by processes such as ion bombardment or chemical mechanical polishing first, and then the second epitaxial structure layer 120b-e can be stacked on the first epitaxial structure layer 120a-e. Similarly, the first-type semiconductor 120b-s1 and the first-type semiconductor 120c-s1 can also perform the above-mentioned thinning process.

[0032] Next, please refer to Figure 3B , etch the second epitaxial structure layer 120b-e from a first side. In this embodiment, for example, etch the third epitaxial structure layer 120c-e and the second epitaxial structure layer 120b-e from the first side. In this embodiment, among the sequentially stacked first epitaxial structure layers 120a-e, second epitaxial structure layers 120b-e, and third epitaxial structure layers 120c-e, one side of the third epitaxial structure layer 120c-e is regarded as the first side, and one side of the first epitaxial structure layer 120a-e is regarded as the second side. In this embodiment, for example, plasma etching technology can be used to select a part from the top surface S3 of the third epitaxial structure layer 120c-e and etch out Figure 3BThe cross-sectional area A1, and sequentially etch the third epitaxial structure layer 120c-e, the second epitaxial structure layer 120b-e, and a part of the first epitaxial structure layer 120a-e to expose the first semiconductor 120a-s1.

[0033] After that, please refer to Figure 3C , provide the second substrate 180, and transfer the first epitaxial structure layer 120a-e, the etched second epitaxial structure layer 120b-e, and the etched third epitaxial structure layer 120c-e to the second substrate 180. Then, remove the first substrate 170.

[0034] After removing the first substrate 170, etch the first epitaxial structure layer 120a-e from the second side. For example, a photoresist layer PR can be disposed on the first epitaxial structure layer 120a-e, and the overlapping portion of the first epitaxial structure layer 120a-e with respect to the second epitaxial structure layer 120b-e and the third epitaxial structure layer 120c-e on the second substrate 180 is removed by using an etching technique (such as plasma etching). In this embodiment, the first epitaxial structure layer 120a-e has a gap GB1 in the projection on the second substrate 180 with respect to the second epitaxial structure layer 120b-e and the third epitaxial structure layer 120c-e, which can be achieved by partially overlapping the region of etching the second epitaxial structure layer 120b and the third epitaxial structure layer 120c-e from the first side and the region of etching the first epitaxial structure layer 120a-e from the second side, and the overlapping portion OA1 is as Figure 3C shown. Specifically, after removing the first substrate 170, according to the photomask pattern design, the wider first epitaxial structure layer 120a-e can be etched, or a part of the second epitaxial structure layer 120b-e and the third epitaxial structure layer 120c-e can be etched again to form the gap GB1. In this way, the remaining first epitaxial structure layer 120a-e after etching forms a plurality of first micro light-emitting elements 120a independent of the second epitaxial structure layer 120b-e and the third epitaxial structure layer 120c-e (in Figure 3C a first micro light-emitting element 120a is schematically shown as a representative).

[0035] Then, please refer to Figure 3D , dispose a photoresist layer PR' on the display device, and only expose a part of the second epitaxial structure layer 120b-e, and etch the second epitaxial structure layer 120b-e in the region where the photoresist layer PR' is not disposed again until the transparent conductive layer 120ci on the top surface of the third epitaxial structure layer 120c-e is exposed. So far, the unetched part of the second epitaxial structure layer 120b-e forms a plurality of second micro light-emitting elements 120b ( Figure 3DTaking a second micro light-emitting element 120b as an example schematically shown. Among them, the light-emitting color of the first micro light-emitting element 120a is different from that of the second micro light-emitting element 120b.

[0036] After that, please refer to Figure 3E , and cover a conductive layer BP on the first micro light-emitting element 120a and the second micro light-emitting element 120b. In this embodiment, for example, the conductive layer BP is made to cover the first micro light-emitting element 120a, the second micro light-emitting element 120b, and the third epitaxial structure layers 120c-e.

[0037] Continue to refer to Figure 3F , flip the display device again, so that the first micro light-emitting element 120a and the second micro light-emitting element 120b are bonded to the bonding layer CM (i.e., the metal wiring layer) on the control panel 100 through the conductive layer BP, and then the substrate 180 and part of the adhesive layer 150 are removed. In this embodiment, due to the setting of the gap GB1 in the steps of the foregoing Figure 3C example, the projections of the first micro light-emitting element 120a and the second micro light-emitting element 120b on the control panel 100 neither overlap nor are connected.

[0038] Please refer to Figure 3G , and set a photoresist layer PR'' on the display device again. Then, please refer to Figure 3H , remove the photoresist PR'' on the part where the third epitaxial structure layers 120c-e overlap with the second micro light-emitting element 120b, and further remove a part of the non-overlapping photoresist PR'' to serve as the reserved space for the gap GB2.

[0039] Please refer to Figure 3I , etch the exposed third epitaxial structure layers 120c-e and the underlying part of the adhesive 150 again. In this way, the remaining unetched third epitaxial structure layers 120c-e become the third micro light-emitting elements 120c.

[0040] Then, please refer to Figure 3J , and remove the photoresist PR''. After that, please refer to Figure 3K , pattern-etch the conductive layer BP to expose the control panel 100, where the conductive layer BP is etched and divided into a plurality of first conductive layers 110a, a plurality of second conductive layers 110b, and a plurality of third conductive layers 110c ( Figure 3Kare schematically shown respectively. Each first micro light-emitting element 110a, second micro light-emitting element 120b, and third micro light-emitting element 120c is correspondingly disposed on a first conductive layer 110a, a second conductive layer 110b, and a third conductive layer 110c. In addition, all the first conductive layers 110a, second conductive layers 110b, and third conductive layers 110c are separated from each other on the control panel 100 and are electrically insulated from each other. In this embodiment, the step of patterning and etching the conductive layer BP further includes etching the bonding layer CM together, so that the bonding layer CM forms a plurality of bonding layers CM that are separated from each other and are electrically insulated from each other. In addition, in Figure 3E the step, after covering the conductive layer BP, a planarization process is further included, for example, chemically mechanical polishing process is used to polish the top surface of the conductive layer BP. In this way, the plurality of first conductive layers 110a have the same first thickness t1, the plurality of second conductive layers 110b have the same second thickness t2, the plurality of third conductive layers 110c have the same third thickness t3, and the first thickness t1, the second thickness t2, and the third thickness t3 are all different from each other. In other words, Figure 3K the step is to perform an insulation process on the first micro light-emitting element 120a, the second micro light-emitting element 120b, and the third micro light-emitting element 120c, and remove the parts of the conductive layer BP and the bonding layer CM that connect them to each other.

[0041] After that, please refer to Figure 3L , an insulating layer 140 is covered on the first micro light-emitting element 120a, the second micro light-emitting element 120b, the third micro light-emitting element 120c, the peripheral surface of the first conductive layer 110a, the peripheral surface of the second conductive layer 110b, the peripheral surface of the third conductive layer 110c, and the control panel 100.

[0042] Then, a light reflecting layer 130 is formed, which covers a part of the first micro light-emitting element 120a, a part of the second micro light-emitting element 120b, a part of the third micro light-emitting element 120c, the insulating layer 140, and the control panel 100. Specifically, in this embodiment, the part of the insulating layer 140 covering the top surface of each micro light-emitting element is completely removed, and then the light reflecting layer 130 is covered on the whole surface. Then, the central area of the light reflecting layer 130 covering the top of each micro light-emitting element is removed, so that the light energy emitted by the plurality of micro light-emitting elements can be transmitted to the outside through the exposed area of the light reflecting layer 130.

[0043] Next, color filters 160a, 160b, and 160c can be respectively formed or disposed on the tops of the first micro light-emitting element 120a, the second micro light-emitting element 120b, and the third micro light-emitting element 120c, and a lens layer 190 is formed or disposed on them.

[0044] Thus, the display device 10c is completed. Therefore, the manufacturing method of the display device according to this embodiment does not require a back-end transfer process, which can greatly improve the yield and reduce costs (such as transfer, repair, etc.). At the same time, a better color gamut can be obtained without using a quantum dot color conversion structure, and the luminous efficiency and lifespan will be greatly improved. In addition, since the lithography etching method is used in this embodiment to define the first micro light-emitting element 120a, the second micro light-emitting element 120b, and the third micro light-emitting element 120c, its precision is much greater than that of mass transfer. Therefore, the upper limit of the resolution of the display device 10c can be greatly improved.

[0045] In addition, the first micro light-emitting element 120a, the second micro light-emitting element 120b, and the third micro light-emitting element 120c of this embodiment are independent of each other on the control panel 100 and do not overlap. Moreover, their light-emitting areas and / or numbers are determined by the patterns of the etching process and do not affect each other. Therefore, in each pixel, the light-emitting areas and / or their numbers within each light-emitting element can be freely allocated or redundantly designed, without considering the mutual crosstalk or parasitic capacitance problems under overlapping.

[0046] Furthermore, the first semiconductor sides of the first micro light-emitting element 120a, the second micro light-emitting element 120b, and the third micro light-emitting element 120c can share an electrode (i.e., connected into one electrode by the light reflection layer 130), which can be completed by only one-time coating, and a complete light reflection surface can be formed in combination with the conductive layer 110.

[0047] The bonding layer CM is also separated during the separation process of the conductive layer BP. Therefore, after being flipped to the control panel 100, the first micro light-emitting element 120a, the second micro light-emitting element 120b, and the third micro light-emitting element 120c can complete the insulation process together while completing their respective bonding.

[0048] Additionally, during the process of stacking each epitaxial structure layer of the present invention, each first semiconductor can be thinned and a roughened structure can be formed on its surface at the same time. The above process can not only optimize the light extraction efficiency of the micro light-emitting element, but also increase the ratio of the interval d to the heights H1, H2, and H3 (i.e., the aspect ratio). In this way, for example, the coating yield of the light reflection layer 130 and the insulation layer 140 can be improved, so as to be applied to a micro light-emitting display with ultra-high resolution.

[0049] Figure 4A - Figure 4B is a partial process schematic diagram of a manufacturing method of a display device according to an embodiment of the present invention. Please refer to Figure 4A - Figure 4B , the manufacturing method of the display device according to this embodiment and Figure 3A - Figure 3LThe manufacturing method of the display device is similar, and the process descriptions of some parts will be omitted and not repeated. The main differences between the two are as follows. In the manufacturing method of the display device of this embodiment, the first epitaxial structure layers 120a-e and the second epitaxial structure layers 120b-e are sequentially stacked on the first substrate 170. After etching the second epitaxial structure layers 120b-e from the first side, the remaining epitaxial structure layers are transferred to the second substrate 180, and then the first epitaxial structure layers 120a-e are etched from the second side, and a conductive layer BP is formed on the remaining epitaxial structure layers. Then, the conductive layer BP is bonded to the bonding layer CM on the control panel 100, as Figure 4A shown. It can be understood that Figure 4A is an embodiment of stacking two epitaxial structure layers, and it corresponds to the Figure 3J state of stacking three epitaxial structure layers. Next, please refer to Figure 4A and Figure 4B correspondingly, and pattern-etch the conductive layer BP. This step may further include sequentially etching a part of at least one of the first epitaxial structure layers 120a-e and the second epitaxial structure layers 120b-e (such as comparing Figure 4A and Figure 4B , as Figure 4B the part marked with the interval d is etched in the figure), so that the projections of the plurality of first micro-light-emitting elements 120a and the plurality of second micro-light-emitting elements 120b, 120b' on the control panel 100 are not connected. In addition, the bonding layer CM is also pattern-etched, as Figure 4B shown.

[0050] Taking Figure 4B as an example, in the step of etching the second epitaxial structure layers 120b-e, the number of the plurality of second micro-light-emitting elements 120b, 120b' formed is at least twice that of the plurality of first micro-light-emitting elements 120a. That is, within one pixel region, the two second micro-light-emitting elements 120b, 120b' are separated from the same second epitaxial structure layer 120b-e.

[0051] In this embodiment, there are only two types of micro-light-emitting elements on the control panel 100. In a high-resolution (Pixels Per Inch, PPI) environment, due to the extremely small pitch between pixels, when there are only two types of micro-light-emitting elements on the control panel, the ratio of the interval d between the micro-light-emitting elements and the maximum height of the micro-light-emitting elements (i.e., the aspect ratio) can be further increased. In this way, problems such as etching failure during the insulation process or poor coating quality of the insulation layer 140 and the light reflection layer 130 can be avoided.

[0052] Similar to the above description of the Figure 3L step, after the Figure 4B step, it can be as Figure 3LThe steps of forming the insulating layer 140, the light reflecting layer 130, the color filters 160a, 160b, 160c and the lens layer 190 are carried out to obtain a display device 10b as shown in Figure 1B Before forming the color filter 160c, a groove g1 can be formed (such as etched) on the top of the first-type semiconductor 120b-s1 of the second micro light-emitting element 120b', and then the color conversion structure 160c-1 is filled into the groove g1, and then the color filter 160c is covered on the color conversion structure 160c-1. In a high-resolution (Pixels Per Inch, PPI) environment, the size of the micro light-emitting element is further reduced, which makes the degree of influence of the external quantum efficiency (EQE) by the sidewall effect increase sharply. In the above embodiment, since the influence on the second micro light-emitting element (such as blue light) is less than that on the third micro light-emitting element (such as red light), a display device using only the first micro light-emitting element 120a and the second micro light-emitting element 120b2 can effectively improve the problem of poor external quantum effect. In addition, the color conversion structure 160c-1 has a better conversion rate for long wavelengths, and the loss of the external quantum effect is relatively small.

[0053] In summary, in the display device of the embodiment of the present invention, since the second thickness of the second conductive layer is greater than the first thickness of the first conductive layer, and the projections of the first micro light-emitting element and the second micro light-emitting element on the control panel do not overlap each other, the micro light-emitting elements of different emission colors are independent of each other and do not overlap. The light-emitting areas in the pixels formed by the micro light-emitting elements of different emission colors can be freely distributed or redundantly designed without the problems of mutual crosstalk or parasitic capacitance under the condition of mutual overlap of the micro light-emitting elements. In the manufacturing method of the display device of the embodiment of the present invention, the first micro light-emitting element and the second micro light-emitting element are stacked and etched, and the first micro light-emitting element and the second micro light-emitting element finally retained on the control panel do not overlap. Therefore, the display device and its manufacturing method of the embodiment of the present invention can integrate micro light-emitting elements of different emission colors together without using a mass transfer process, which can greatly improve the manufacturing yield of the display device and reduce the transfer and repair costs.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A display device, characterized in that, Comprising: A control panel; A plurality of conductive layers, each directly connected to the control panel, and the plurality of conductive layers are divided into a plurality of first conductive layers having a first thickness and a plurality of second conductive layers having a second thickness, wherein the second thickness is greater than the first thickness; A plurality of first micro light-emitting elements, each disposed on one of the first conductive layers, each of the first micro light-emitting elements having a first light-emitting layer that emits light of a first color; And A plurality of second micro light-emitting elements, each disposed on one of the second conductive layers, each of the second micro light-emitting elements having a second light-emitting layer that emits light of a second color different from the first color; Wherein, the projections of the plurality of first micro light-emitting elements and the plurality of second micro light-emitting elements on the control panel do not overlap with each other.

2. The display device according to claim 1, characterized in that, It further includes a light reflection layer covering the peripheral surfaces of the plurality of first micro light-emitting elements, the plurality of second micro light-emitting elements, the plurality of first conductive layers, and the plurality of second conductive layers, and the plurality of first conductive layers and the plurality of second conductive layers contain light reflection materials.

3. The display device according to claim 2, characterized in that, The light reflection layer is a common electrode layer and is electrically connected to the plurality of first micro light-emitting elements and the plurality of second micro light-emitting elements.

4. The display device according to claim 2, characterized in that, It further includes an insulating layer disposed between the light reflection layer and the first micro light-emitting element or the second micro light-emitting element to cover the plurality of first micro light-emitting elements and the plurality of second micro light-emitting elements together, and the insulating layer is a single film layer.

5. The display device according to claim 1, characterized in that, The plurality of conductive layers are disposed on the control panel separately from each other and are electrically independent of each other.

6. The display device according to claim 1, characterized in that, The second thickness is greater than the height of the top surface of the first micro light-emitting element relative to the control panel.

7. The display device according to claim 1, characterized in that, It further includes a color conversion structure disposed on a part of the plurality of second micro light-emitting elements, the color conversion structure being used to convert the light of the second color into light of a third color, and the third color is different from the first color.

8. The display device according to claim 7, characterized in that, Each of the part of the second micro light-emitting elements includes an epitaxial structure, the second light-emitting layer is located within the epitaxial structure, and a groove is provided between the top surface of the epitaxial structure away from the control panel and the second light-emitting layer, and the color conversion structure is disposed within the groove.

9. The display device according to claim 1, characterized in that, Each of the first micro light-emitting elements and each of the second micro light-emitting elements has a first type semiconductor and a second type semiconductor, and the ratio of the thickness of the first type semiconductor to the second type semiconductor is between 1 and 1.

6.

10. The display device according to claim 9, characterized in that, The first type semiconductor is located on the side of the first micro light-emitting element or the second micro light-emitting element away from the control panel, and the surface of the first type semiconductor has a roughened structure.

11. The display device according to claim 1, characterized in that, The control panel defines a plurality of pixel regions, and at least one of the pixel regions includes the first micro light-emitting element, the second micro light-emitting element, and a third micro light-emitting element disposed on the conductive layer, wherein the pixel region includes at least four micro light-emitting elements.

12. The display device according to claim 11, characterized in that, The plurality of conductive layers of the plurality of pixel regions have three or fewer thicknesses.

13. The display device according to claim 1, characterized in that, It further includes a plurality of third micro light-emitting elements, wherein the plurality of conductive layers further include a plurality of third conductive layers having a third thickness greater than the second thickness, and each of the third micro light-emitting elements is respectively disposed on one of the third conductive layers, and each of the third micro light-emitting elements has a third light-emitting layer that can emit light of a third color different from the first color and the second color.

14. The display device according to claim 1, characterized in that, The surface of the control panel includes a plurality of bonding layers, each of the bonding layers having a bonding surface and a side wall surface connecting the bonding surface, and the side wall surface is an etched surface, and the plurality of conductive layers are bonded to the plurality of bonding surfaces to connect the control panel.

15. The display device according to claim 14, characterized in that, The peripheral side surfaces of the plurality of conductive layers and the plurality of side wall surfaces of the plurality of bonding layers form a continuous surface.

16. The display device according to claim 1, characterized in that, The peripheral side surfaces of the plurality of conductive layers are etched surfaces.

17. A manufacturing method of a display device, characterized in that, Comprising: Sequentially stacking a first epitaxial structure layer and a second epitaxial structure layer on a first substrate; Etching the second epitaxial structure layer from a first side and etching the first epitaxial structure layer from a second side to form a plurality of first micro light-emitting elements and a plurality of second micro light-emitting elements, wherein the emission colors of the plurality of first micro light-emitting elements are different from those of the plurality of second micro light-emitting elements; Covering a conductive layer on the first micro light-emitting elements and the second micro light-emitting elements, so that the first micro light-emitting elements and the second micro light-emitting elements are bonded to the control panel by the conductive layer, wherein the projections of the plurality of first micro light-emitting elements and the plurality of second micro light-emitting elements on the control panel do not overlap; And Pattern-etching the conductive layer to expose the control panel, wherein the conductive layer is etched and divided into a plurality of first conductive layers and a plurality of second conductive layers, the plurality of first micro light-emitting elements are correspondingly disposed on the plurality of first conductive layers, the plurality of second micro light-emitting elements are correspondingly disposed on the plurality of second conductive layers, and the plurality of first conductive layers and the plurality of second conductive layers are separated from each other on the control panel and are electrically insulated from each other.

18. The manufacturing method of a display device according to claim 17, characterized in that, In the step of etching the second epitaxial structure layer, the number of the second micro light-emitting elements formed is at least twice that of the plurality of first micro light-emitting elements.

19. The manufacturing method of a display device according to claim 17, characterized in that, The control panel further includes a bonding layer, and the conductive layer is bonded to the control panel by the bonding layer, wherein the step of pattern-etching the conductive layer further includes etching the bonding layer together, so that the bonding layer forms a plurality of bonding layers that are separated from each other and are electrically insulated from each other.

20. The manufacturing method of a display device according to claim 17, characterized in that, After covering the conductive layer, a planarization process is further included to make the plurality of first conductive layers have the same first thickness, the plurality of second conductive layers have the same second thickness, and the first thickness is different from the second thickness.

21. The manufacturing method of a display device according to claim 17, characterized in that, After etching the second epitaxial structure layer from the first side, it further includes: Providing a second substrate; Transferring the first epitaxial structure layer and the etched second epitaxial structure layer to the second substrate; and Removing the first substrate to etch the first epitaxial structure layer on the second side.

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