TWI768272B - Micro-led driving backplate and display panel - Google Patents

Abstract

A micro-LED driving backplate and a display panel are provided. A plurality of sub-pixel regions arranged in rows and columns are divided on the surface of the substrate of the driving backplane for setting a micro-LED array. The thickness of the substrate around the sub-pixel region is thinned to form a recess portion. The recess portion is not provided with a micro-LED. In the conformal process of the display panel or the product bending applications, in addition to avoiding damage to the micro-LED due to pulling, the corresponding thinning structure of the substrate can also be designed according to the required deformation of the product shape.

Description

Micro-LEDs drive backplanes and display panels

The present invention relates to a micro-light-emitting diode display technology, in particular to a micro-light-emitting diode driving backplane and a display panel.

Micro light-emitting diode (Micro LED) display technology is a new generation of display technology after organic light-emitting diode (OLED), and a large number of domestic and foreign manufacturers are attacking it one after another, and its market prospects are promising. The biggest advantage of the micro light-emitting diode display panel comes from the reduction of the LED volume to about 1% of the traditional LED size, the size and pixel pitch are reduced to the micron level, and each pixel can be controlled by addressing. And single-point driving light, making the overall module smaller, and has the characteristics of high brightness, low power consumption, ultra-high resolution and color saturation.

Then, the micron-level RGB three-color (red/blue/green) LEDs are transferred to rigid, flexible transparent or opaque circuit substrates through mass transfer technology, and the protective layer and upper electrodes are completed by physical deposition process. package to complete Micro LED Displays of various sizes and simple structures.

At present, the preparation method of the micro-LED display panel is mainly based on transfer technology. However, due to the limitation of the manufacturing process environment of the micro-LED chip (chip) in the early stage of the process, a wafer must be used as the substrate epitaxy. After being crystallized, the micro-LED chips are transferred from the wafer substrate to the driving backplane in large quantities, which can then be used to manufacture micro-LED display panels.

Since the micro-LEDs use inorganic materials, they have the advantages of long service life and simple structure when applied to flexible displays. However, in the conformal process of flexible display panels, stress does not act in a single direction, and the light-emitting elements may be affected during the process. It will cause splitting because it cannot bear it; in actual use, it is also easy to damage the components due to the deviation of the stack design from the mechanical center plane (or axis) (Mechanical Neutral Plan, NP) and excessive stress.

The main purpose of the present invention is to provide a micro-light emitting diode driving backplane and a display panel. The substrate of the driving backplane is designed to have a structure with different thicknesses, which can avoid the problem of Stress causes interface splitting or component damage, thereby increasing process yield and product life.

In order to achieve the above-mentioned object, the present invention provides a micro-LED driving backplane, which includes a substrate and a plurality of driving elements, a plurality of sub-pixel regions arranged in rows and columns are defined on the surface of the substrate, and a plurality of sub-pixel regions are defined on the surface of the substrate. The surface of the substrate outside the area has a concave portion, and each at least one driving element is arranged in each sub-pixel area, and each driving element is correspondingly provided with a micro light-emitting diode.

In addition, the present invention also provides a micro-LED display panel, comprising the aforementioned micro-LED driving backplane and a plurality of micro-LEDs respectively disposed on the aforementioned driving elements.

In this invention, the said board|substrate is a flexible board|substrate.

In the present invention, the aforementioned concave portion includes an edge region surrounding the outside of the sub-pixel regions and a central region spaced between the sub-pixel regions.

In the present invention, the aforementioned micro-LED driving panel further includes a plurality of wirings, which are arranged in the recesses on the surface of the substrate and extend into the sub-pixel regions to be electrically connected to the corresponding driving elements.

In the present invention, the material of the aforementioned wiring is a stretch-resistant metal or composite material.

In the present invention, the aforementioned micro-LED display panel further includes an encapsulation layer, which is wrapped around the driving element and the micro-LED on each sub-pixel region.

In the present invention, the aforementioned micro-LEDs include red micro-LEDs, green micro-LEDs, blue micro-LEDs or combinations thereof.

In the present invention, each sub-pixel region is provided with red light emitting diodes, green light emitting diodes, blue light emitting diodes, or a combination thereof.

In the micro-light-emitting diode driving backplane and display panel provided by the present invention, the micro-light-emitting diodes are not provided in the recessed part of the substrate surface, so that the micro-light-emitting diodes do not have any effect during the molding process or the bending process. It is easy to cause damage due to excessive stress, which can improve the process yield, improve the product reliability of the display panel, prolong its service life, and is especially suitable for the development of flexible micro-LED display devices, in industrial applications. will be very competitive.

The following detailed description will be given in conjunction with the accompanying drawings through specific embodiments, so as to more easily understand the purpose, technical content, characteristics and effects of the present invention.

Please refer to Figures 1 to 3. FIG. 1 is a side view of a micro-LED driving backplane 100 according to a first embodiment of the present invention, and FIG. 2 is a micro-light emitting diode including the micro-LED driving backplane 100 of FIG. 1 FIG. 3 is a side view of the diode display panel 200 , and FIG. 3 is a top view of the micro-LED display panel 200 of FIG. 2 .

The micro-LED driving backplane 100 shown in FIG. 1 includes a substrate 10 and a plurality of driving elements 20 , and the substrate 10 can be a flexible substrate with flexural properties. The surface of the substrate 10 defines a plurality of There are sub-pixel regions 11, and there is a recess 12 on the surface of the substrate 10 outside the sub-pixel region 11. That is to say, the structure of the substrate 10 has different thicknesses through local thinning, and the thickness of the recess 12 is relatively Small. However, at least one driving element 20 is respectively arranged in each sub-pixel area 11 , and the concave portion 12 outside the sub-pixel area 11 is not arranged. In this embodiment, each sub-pixel region 11 is respectively provided with one driving element 20 , and each driving element 20 can be provided with one micro-LED 30 (see FIGS. 2 and 3 ).

The micro-LED display panel 200 shown in FIG. 2 includes the micro-LED driving backplane 100 shown in FIG. 1 and a plurality of micro-LEDs corresponding to each driving element 20 respectively. 30 , and the surrounding of the driving element 20 and the micro light-emitting diode 30 on each sub-pixel region 11 is also covered with an encapsulation layer 40 . From the micro-LED display panel 200 shown in FIG. 3 , it can be clearly seen that the recessed portion 12 of the substrate 10 includes an edge region 13 surrounding the outer side of the sub-pixel region 11 and spaced between the sub-pixel regions 11 . Central area 14 between.

Specifically, the number, arrangement and emission color of the micro-LEDs 30 arranged in each sub-pixel region 11 can be designed correspondingly according to requirements. In this embodiment, the number of the micro-LEDs 30 in each sub-pixel region 11 is one. As shown in the figure, the micro-LEDs 30 are arranged in an array of 3 columns and 3 columns. The total is 9. Further, in this embodiment, three primary colors of red, green and blue are used for color display, and the micro-LEDs 30 include red micro-LEDs, green micro-LEDs and blue micro-LEDs. The light-emitting colors of the light-emitting diodes 30 are the same, and the light-emitting colors of the micro-light-emitting diodes 30 in the same row are blue light-emitting diodes, green light-emitting diodes, and red-light micro-emitting diodes in sequence, and This arrangement order is only an example, and is not limited in practical application.

Please refer to FIG. 4A to FIG. 4C and FIG. 5A to FIG. 5C to illustrate in sequence how to manufacture the micro-LED driving backplane 100 and the micro-LED display panel 200 disclosed in the first embodiment. method, the steps of which include:

As shown in FIGS. 4A and 5A , a plurality of sub-pixel regions 11 arranged in rows and columns are defined on the surface of a substrate 10 , and the surface of the substrate 10 other than the sub-pixel regions 11 is thinned to form recesses 12 . Then, as shown in FIG. 4B and FIG. 5B , a yellow light process is used to form the driving element 20 in each sub-pixel region 11 , and then a stretch-resistant metal or composite material is used to fabricate a plurality of traces on the outside of the surface of the substrate 10 . Lines 15 . These traces 15 extend from the recessed portion 12 toward the sub-pixel region 11 to be electrically connected to the corresponding driving elements 20 , thereby completing the fabrication of the micro-LED driving backplane 100 . Then, as shown in FIG. 4C and FIG. 5C , the wafer with a plurality of micro-LEDs 30 is transferred to the micro-LED driving substrate 100 by using a transfer technique, so that the micro-LEDs 30 are bonded to the micro-LEDs 30 . Corresponding to the driving element 20 , the driving element 20 and the micro-LEDs 30 in each sub-pixel region 11 are then covered with the encapsulation layer 40 to complete the packaging of the micro-LED display panel 200 .

In addition, please refer to FIG. 6 , which is a micro-LED driving backplane 100 ′ disclosed according to a second embodiment of the present invention and a micro-LED driving backplane 100 ′ fabricated by using the micro-LED driving backplane 100 ′ A top view of the polar body display panel 200'.

Different from the first embodiment, each sub-pixel region 11' in this embodiment is respectively provided with three driving elements 20', and each driving element 20' is provided with a micro light-emitting diode 30'. The number of micro-LEDs 30' in the pixel area 11' is three, and the figure shows three sub-pixel areas 11', and the total number of micro-LEDs 30' is 9, which are also arranged in 3 An array of rows and 3 columns. Further, the emission colors of the three micro-LEDs 30' in the same row are blue micro-LEDs, green micro-LEDs and red micro-LEDs in sequence, and the micro-LEDs in the same row are The light-emitting colors of the diodes 30' are the same, and this arrangement is only an example, and is not limited in practical application.

Please refer to FIG. 7 , which is a micro LED driving backplane 100 ″ and a micro LED driving backplane 100 ″ disclosed according to the third embodiment of the present invention. A top view of the display panel 200".

Different from the first embodiment and the second embodiment, each sub-pixel area 11" in this embodiment is respectively provided with 9 driving elements 20" arranged in 3 rows and 3 columns, and each driving element 20" is provided with A micro-LED 30", and the figure shows two sub-pixel areas 11" arranged up and down, therefore, each sub-pixel area 11" also includes 9 micro-LEDs arranged in 3 rows and 3 columns Diode 30". Further, the emission colors of the three micro-LEDs 30" in the same row are blue micro-LEDs, green micro-LEDs and red micro-LEDs in sequence. In addition, the light-emitting colors of the micro-LEDs 30 ″ in the same row are the same, and this arrangement is only an example, and is not limited in practical application.

Because Tensile Strength = E*h. (E = elastic modulus, h = thickness). Due to the change of thickness or the change of shape, the stress distribution of the cross-section after force is no longer kept uniform. When the structure is stretched, the stress will be concentrated in the position of weak tensile strength. Therefore, according to this concept, the present invention makes the substrate of the micro-LED driving backplane into a structure with different thicknesses, that is, the area around the sub-pixels is cleared and the substrate is thinned, so that the shaping process of the display panel is performed. Or when the product is flexed, it can prevent the micro LED element from being pulled.

Furthermore, the present invention can design the width and depth of the concave portion formed after the substrate of the micro-LED driving backplane is thinned and cleared according to the required stretching amount of the product shape. Can be used to predict the relative position of the display area after shaping.

Further, please refer to FIG. 8 , which shows the structural changes before and after the molding process of the micro-LED display panel 100 .

The recessed portion 12 of the substrate 10 in the micro-LED display panel 100 shown in FIG. 8 originally has a width D and a depth T, and in FIG. 8B, it is attached to the protective glass through a molding process, and the width is increased by ΔD , the depth becomes smaller by ΔT, that is, the shaped depression 12 has a width of D+ΔD and a depth of T-ΔT.

Next, the length L1 , the height d1 , the side wall inclination angle θ of the recessed portion 12 , and the length L2 and the height (thickness) d2 of the substrate are defined in FIG. 9 . The following table 1 shows the structural data of 4 groups of substrates with different product shapes.

Table I group L1 (μm) L2 (μm) θ (degrees) d2 (μm) d1 (μm) (a) 20 30 90 20 5 (b) 20 30 45 20 5 (c) 5 30 45 20 5 (d) 5 30 90 20 5

The present invention can simulate the stress and deformation generated by the thermoplastic process according to different product shapes. As shown in Figure 10, the tensile curves of 4 groups of different product shapes in Table 1 are shown, and then the data collected from the material structure can be reversed. The shape is required, and the corresponding tensile strength is designed according to the tensile pre-measurement. According to the required tensile amount, for example, the required shape deformation ε is ΔD. It can be seen from Figure 10 that the group (a ) or the board design of the product appearance of group (b) shall be considered.

To sum up, according to the micro-LED driving backplane and micro-LED display panel provided by the present invention, the thickness of the substrate of the micro-LED driving backplane is designed to be partially thinned, and this reduction The recessed part formed after thinning is not provided with micro-LEDs, which can prevent the micro-LEDs from being pulled and cause interface splitting and device damage during the molding process of the display panel or the application of product bending. , especially suitable for the development of the substrate structure of the flexible micro-LED display panel. At the same time, the above-mentioned feature of the thinning position of the substrate can be designed according to the required deformation amount of the product appearance, and its construction is simple and easy to realize.

The above-mentioned embodiments are only intended to illustrate the technical ideas and characteristics of the present invention, and the purpose is to enable those who are familiar with the art to fully understand the content of the present invention and implement them accordingly, and should not limit the patent scope of the present invention , that is, all equivalent changes or modifications made in accordance with the spirit disclosed in the present invention should still be covered by the patent scope of the present invention.

100, 100', 100": Micro LED driver backplane 10: Substrate 11, 11', 11": sub-pixel area 12: Depressed part 13: Edge Zone 14: Central District 15: Route 20, 20', 20": drive element 30, 30', 30": Micro LEDs 40: Encapsulation layer 200, 200', 200": Micro-LED display panels D, D+ΔD: width T, T-ΔT: depth L1, L2: length d1, d2: height θ: Sidewall inclination angle

FIG. 1 is a side view of a micro-LED driving backplane according to a first embodiment of the present invention. FIG. 2 is a side view of a micro-LED display panel including the micro-LED driving backplane of FIG. 1 FIG. 3 is a top view of the micro-LED display panel of FIG. 2 . FIGS. 4A to 4C are structural top views of the method steps of fabricating the micro-LED driving backplane disclosed in the first embodiment of the present invention. FIGS. 5A to 5C are structural side views of the steps of the method for fabricating the micro-LED driving backplane disclosed in the first embodiment of the present invention, which correspond to FIGS. 4A to 4C respectively. FIG. 6 is a top view of a micro-LED driving backplane and a micro-LED display panel fabricated therefrom according to the second embodiment of the present invention. FIG. 7 is a top view of a micro-LED driving backplane and a micro-LED display panel fabricated therefrom according to a third embodiment of the present invention. FIG. 8 shows the structural changes before and after the molding process of the micro-LED display panel. FIG. 9 is the substrate structure of the micro-LED driving backplane. Figure 10 shows the tensile curves of different product shapes.

100: Micro LED driver backplane

10: Substrate

11: Sub-pixel area

12: Depressed part

20: Drive components

Claims (13)

A micro-light-emitting diode driving backplane, used for transferring a plurality of micro-light-emitting diodes to the micro-light-emitting diode driving backplane in the wafer transfer technology, the micro-light-emitting diode driving backplane comprising: a a substrate, a plurality of sub-pixel regions arranged in rows and columns are defined on the surface of the substrate, and a recessed portion is provided on the surface of the substrate outside the sub-pixel regions; and a plurality of driving elements, each at least two driving elements are arranged in A micro-light emitting diode is arranged on each of the sub-pixel regions and on each of the driving elements. The micro-LED driving backplane as claimed in claim 1, wherein the substrate is a flexible substrate. The micro-LED driving backplane as claimed in claim 1, wherein the recessed portion comprises an edge region surrounding the outside of the sub-pixel regions and a central region spaced between the sub-pixel regions . The micro-LED driving backplane as claimed in claim 1, further comprising a plurality of wirings, the wirings are arranged in the recessed portion and extend into the sub-pixel regions to be electrically connected to corresponding drivers element. The micro-LED driving backplane as claimed in claim 4, wherein the materials of the wires are stretch-resistant metal or composite materials. A micro-LED display panel, comprising: a micro-LED driving backplane, including: a substrate, the surface of the substrate defines a plurality of sub-pixel regions arranged in rows and columns, and in the sub-pixel regions The other surface of the substrate has a recess; and a plurality of driving elements, each at least two driving elements are arranged in each of the sub-pixel regions; and a plurality of micro light-emitting diodes, which are transferred to the Micro LED The driving backplane is respectively arranged on the driving elements. The micro-LED display panel of claim 6, wherein the substrate is a flexible substrate. The micro-LED display panel of claim 6, wherein the recessed portion includes an edge region surrounding the outside of the sub-pixel regions and a central region spaced between the sub-pixel regions. The micro-LED display panel as claimed in claim 6, wherein the micro-LED driving panel further comprises a plurality of wirings, the wirings are arranged in the recessed portion on the surface of the substrate and extend to the sub-pictures In the pixel area, it is electrically connected to the corresponding driving element. The micro-LED display panel according to claim 9, wherein the wires are made of stretch-resistant metal or composite material. The micro-LED display panel as claimed in claim 6, further comprising an encapsulation layer, the packaging layer wraps around the driving element and the micro-LED on each of the sub-pixel regions. The micro-LED display panel of claim 6, wherein the micro-LEDs comprise red micro-LEDs, green micro-LEDs, blue micro-LEDs or combinations thereof. The micro-LED display panel as claimed in claim 12, wherein each sub-pixel region is provided with red micro-LEDs, green micro-LEDs, blue micro-LEDs or the like combination.

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