Micro-LED display panel and preparation method thereof

Abstract

The application relates to a Micro-LED display panel. The application uses a Micro-LED chip with two symmetrical light-emitting structures as a single chip for assembling an LED display panel, which can not only ensure the convenience of electrical connection, but also ensure the uniformity of light emission, reduce the distance between subpixels and improve the resolution, with each light-emitting structure serving as a subpixel component. In particular, a barrier wall is arranged between Micro-LED chips of the same color to ensure the light emission independence of the RGB composed pixel points.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of LED packaging display, and particularly relates to a Micro-LED display panel. BACKGROUND

[0002] The stability of the organic light-emitting layer of a traditional organic display panel structure is poor, so the service life of the display panel is short, and the driving voltage is large, which is not conducive to reducing energy consumption. Therefore, Micro-LED display panels are widely studied, which have the advantages of small energy consumption, long service life, small light-emitting temperature and small volume.

[0003] However, the existing Micro-LED display panel is small in size, and is not easy to align and adsorb during transfer, which is not conducive to the mass transfer efficiency and reliability of the Micro-LED chip, and the arrangement mode greatly affects the display effect. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art, and provides a Micro-LED display panel, which comprises a substrate and a Micro-LED chip array arranged on the substrate; the Micro-LED chip array comprises a plurality of columns of first color LED chips, a plurality of columns of second color LED chips and a plurality of columns of third color LED chips, and the plurality of columns of first color LED chips, the plurality of columns of second color LED chips and the plurality of columns of third color LED chips are arranged in the row direction in turn; and the plurality of columns of first color LED chips comprise a plurality of first color LED chips, the plurality of columns of second color LED chips comprise a plurality of second color LED chips, and the plurality of columns of third color LED chips comprise a plurality of third color LED chips; each first color LED chip, second color LED chip and third color LED chip comprises a first light-emitting structure and a second light-emitting structure which are symmetrical in the column direction and arranged in turn; wherein in the row direction, each color LED chip partially overlaps with two LED chips of different colors, and the first light-emitting structure and the second light-emitting structure are arranged in turn with intervals.

[0005] As a preferred scheme, when viewed from above, the first light-emitting structure and the second light-emitting structure form a sandglass shape, the first light-emitting structure and the second light-emitting structure are respectively triangular, semicircular or trapezoidal, and the light-emitting areas of the first light-emitting structure and the second light-emitting structure gradually decrease in the direction towards the axis of symmetry.

[0006] As a preferred scheme, in each LED chip, the first light-emitting structure and the second light-emitting structure each comprise an epitaxial structure on a substrate layer, and the epitaxial structure comprises an N-type epitaxial layer, a light-emitting layer and a P-type epitaxial layer.

[0007] As a preferred scheme, in each LED chip, the P-type epitaxial layer has a first electrode thereon, an isolation structure is provided outside the epitaxial structure, and a second electrode is provided outside the isolation structure; the second electrode is located on both sides of the narrow part of the hourglass shape.

[0008] As a preferred scheme, in each LED chip, the substrate layer has a shape of wide at both ends and narrow in the middle when viewed from above, and the narrow part of the substrate layer is formed as a concave part.

[0009] As a preferred scheme, in two LED chips of different colors adjacent in the row direction, one top corner of one LED chip is embedded in the concave part of the other LED chip.

[0010] As a preferred scheme, in the column direction, a barrier is provided between two LED chips of the same color adjacent to each other; in the row direction, the length of the barrier is greater than or equal to the width of each LED chip.

[0011] As a preferred scheme, the height of the barrier is greater than the height of each LED chip.

[0012] The present application has the following beneficial effects:

[0013] The present application uses a Micro-LED chip with two light-emitting structures arranged symmetrically as a single chip for assembling an LED display panel, which not only ensures the convenience of electrical connection, but also ensures the uniformity of light emission and reduces the distance between sub-pixels to improve the resolution, as each light-emitting structure is a component of a sub-pixel. In particular, a barrier is provided between Micro-LED chips of the same color to ensure the light emission independence of the RGB composed pixel points. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 A Micro-LED chip arrangement diagram of the present application Micro-LED display panel.

[0015] Figure 2 A cross-sectional view along the A1A2 line of Figure 1 .

[0016] Figure 3 A cross-sectional view along the B1B2 line of Figure 1 .

[0017] Figure 4 A top view of a single Micro-LED chip structure of the present application.

[0018] Figure 5 A cross-sectional view of a single Micro-LED chip structure of the present application.

[0019] Reference Signs List

[0020] 10 - Micro-LED chip 10;

[0021] 20 - barrier wall;

[0022] 11 - substrate;

[0023] 12 - N-type epitaxial layer;

[0024] 13 - light-emitting layer;

[0025] 14 - P-type epitaxial layer;

[0026] 15 - P electrode;

[0027] 16 - N electrode;

[0028] 17 - insulating layer;

[0029] R - first color LED chip;

[0030] G - second color LED chip;

[0031] B - third color LED chip. DETAILED DESCRIPTION

[0032] For the purpose of facilitating the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0033] As Figures 1-5 shown, the present embodiment provides a Micro-LED display panel, which includes an array of Micro-LED chips on a substrate, the substrate including a plurality of driving TFT elements and driving circuits electrically connected to the array of Micro-LED chips to drive the chips to emit light to form a display structure.

[0034] The array of Micro-LED chips includes a plurality of Micro-LED chips 10, the plurality of Micro-LED chips 10 including LED chips of at least three colors, for example, a plurality of columns of first color LED chips R, a plurality of columns of second color LED chips G, and a plurality of columns of third color LED chips B as shown in the figure, the plurality of columns of first color LED chips R, the plurality of columns of second color LED chips G, and the plurality of columns of third color LED chips B being arranged in the row direction in turn.

[0035] As Figure 1As shown, each Micro-LED chip 10 is in the shape of an hourglass when viewed from above, with the length direction being the column direction and the width direction being the row direction. Referring to Figure 5 Each Micro-LED chip 10 includes a substrate 11 and functional layers on the substrate 11. The substrate 11 can be a transparent substrate to form a flip-chip structure. The substrate 11 includes functional layers such as an N-type epitaxial layer 12, a light-emitting layer 13, and a P-type epitaxial layer 14.

[0036] The area of the substrate 11 can be larger than the area of the light-emitting layer 13 and the P-type epitaxial layer 14, but the area of the substrate 11 is equal to the area of the N-type epitaxial layer 12, so that the N-type epitaxial layer 12 completely covers the upper surface of the substrate 11. The substrate 11 can be in the shape of an hourglass, as shown in Figure 4 The Micro-LED chip 10 has a symmetrical structure that narrows and then widens in the length direction, which can be a spliced structure of two isosceles trapezoids.

[0037] Each Micro-LED chip 10 has two light-emitting structures symmetrically arranged in the length direction, each of which can be in the shape of a triangle, a trapezoid, a half-ellipse, or a half-circle. The two light-emitting structures of each Micro-LED chip 10 are also in the shape of an hourglass, and the hourglass shape is mainly formed by the light-emitting layer 13 and the P-type epitaxial layer 14 formed by etching, while the N-type epitaxial layer 12 is laid on the entire substrate 11, as shown in Figure 4 .

[0038] The narrow part of the substrate 11 is wider than the narrow part of the light-emitting layer 13 and the P-type epitaxial layer 14, so that an electrical connection part can be formed between the narrow part of the substrate 11 and the narrow part of the light-emitting structure to facilitate the electrode lead-out on the N-type epitaxial layer 12 side. An insulating layer 17 is provided on the N-type epitaxial layer 12 and between the narrow part of the substrate 11 and the narrow part of the light-emitting layer 13 and the P-type epitaxial layer 14. The insulating layer 17 can be provided on both sides of the narrow part of the light-emitting layer 13 and the P-type epitaxial layer 14 to form the insulating layer of the N electrode 16 and the light-emitting layer 13 and the P-type epitaxial layer 14. In particular, the thickness of the insulating layer 17 gradually decreases and then gradually increases along the length direction of the Micro-LED chip 10, so that enough space is left between the insulating layer 17 and the narrow part of the substrate 11 to form the N electrode 16.

[0039] The P electrode 15 is also provided on the P-type epitaxial layer 14 and is also surrounded by the insulating layer 17. In this way, a flip-chip structure is formed, and the P electrode 15 and the N electrode 16 can be bonded to the substrate by solder to achieve electrical connection and electrical driving.

[0040] Referring to Figures 1-3, the different color LED chips adjacent to each LED chip are staggered in the row direction by half the length of the chip, so that in the Nth row and the N+1th row, the LED chip of a certain color is adjacent to two LED chips of another color. Among them, in a certain row, the first color LED chip R, the second color LED chip G and the third color LED chip B constitute a pixel, and the single light emitting structure of each Micro-LED chip 10 constitutes a sub-pixel of the pixel.

[0041] For the compactness of arrangement, in each LED chip, the substrate 11 layer has a shape of wide at both ends and narrow in the middle, and the narrow part of the substrate 11 is formed as a concave part. In two different color LED chips adjacent in the row direction, one corner of one LED chip is embedded in the concave part of the other LED chip.

[0042] In addition, in the column direction, there is a barrier wall 20 between two adjacent LED chips of the same color, which can be formed by a polymer material dispersed with black dye; in the row direction, the length of the barrier wall 20 is greater than or equal to the width of each LED chip. Each barrier wall 20 has a segmented structure in the form of a line segment, and is located on both sides of the narrow part of the substrate 11 of each LED chip. And, in order to prevent crosstalk between different pixels, the height of the barrier wall 20 is greater than the height of each LED chip.

[0043] The present application uses a Micro-LED chip with two light emitting structures arranged symmetrically as a single chip for the assembly of an LED display panel, which not only ensures the convenience of electrical connection, but also ensures the uniformity of light emission as each light emitting structure is a component of a sub-pixel, and reduces the distance between sub-pixels to improve resolution. In particular, a barrier wall is also provided between Micro-LED chips of the same color to ensure the independent light emission of the RGB composed pixel points.

[0044] In the Micro-LED display panel, a substrate and a Micro-LED chip array arranged on the substrate are included; the Micro-LED chip array includes a plurality of columns of first color LED chips, a plurality of columns of second color LED chips, and a plurality of columns of third color LED chips, which are arranged in a row direction in a cyclic manner; each of the plurality of columns of first color LED chips includes a plurality of first color LED chips, each of the plurality of columns of second color LED chips includes a plurality of second color LED chips, and each of the plurality of columns of third color LED chips includes a plurality of third color LED chips; each of the first color LED chips, the second color LED chips, and the third color LED chips includes first and second light emitting structures that are symmetrical in a column direction and arranged in sequence; and in the row direction, each color LED chip partially overlaps two LED chips of different colors, and the first and second light emitting structures are arranged in sequence with a gap.

[0045] As a preferred solution, the first light emitting structure and the second light emitting structure form a sandglass shape when viewed from above, the first light emitting structure and the second light emitting structure are triangular, semi-elliptical, or trapezoidal, and the light emitting areas of the first light emitting structure and the second light emitting structure gradually decrease in a direction toward a symmetry axis.

[0046] As a preferred solution, in each LED chip, the first light emitting structure and the second light emitting structure each include an epitaxial structure on a substrate layer, and the epitaxial structure includes an N-type epitaxial layer, a light emitting layer, and a P-type epitaxial layer.

[0047] As a preferred solution, in each LED chip, a first electrode is provided on the P-type epitaxial layer, an isolation structure is provided outside the epitaxial structure, and a second electrode is provided outside the isolation structure; the second electrode is located on both sides of a narrow part of the sandglass shape.

[0048] As a preferred solution, in each LED chip, the substrate layer has a shape with wide ends and a narrow middle, and the narrow part of the substrate layer is formed as a concave part.

[0049] As a preferred solution, in the row direction, one of two adjacent LED chips of different colors has one corner embedded in the concave part of the other LED chip.

[0050] As a preferred solution, in the column direction, a barrier is provided between two adjacent LED chips of the same color; and in the row direction, the length of the barrier is greater than or equal to the width of each LED chip.

[0051] As a preferred solution, the height of the retaining wall is greater than the height of each LED chip.

[0052] The above embodiments are only illustrative of the principles and effects of the present application, and are not intended to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1.A Micro-LED display panel, comprising a substrate and a Micro-LED chip array arranged on the substrate; the Micro-LED chip array comprises a plurality of columns of first color LED chips, a plurality of columns of second color LED chips and a plurality of columns of third color LED chips, which are arranged in a row direction in a cyclic manner; and the plurality of columns of first color LED chips comprise a plurality of first color LED chips, the plurality of columns of second color LED chips comprise a plurality of second color LED chips, and the plurality of columns of third color LED chips comprise a plurality of third color LED chips; each of the first color LED chip, the second color LED chip and the third color LED chip comprises a first light emitting structure and a second light emitting structure which are symmetrical and arranged in sequence in a column direction; wherein, in the row direction, each color LED chip partially overlaps with two LED chips of different colors, and the first light emitting structure and the second light emitting structure are arranged in sequence with a spacing therebetween; when viewed from above, the first light emitting structure and the second light emitting structure form an hourglass shape, the first light emitting structure and the second light emitting structure are triangular, semi-elliptical or trapezoidal in shape, and the light emitting areas of the first light emitting structure and the second light emitting structure gradually decrease in a direction towards a symmetry axis; in each LED chip, the first light emitting structure and the second light emitting structure each comprise an epitaxial structure on a substrate layer, and the epitaxial structure comprises an N-type epitaxial layer, a light emitting layer and a P-type epitaxial layer; in each LED chip, the P-type epitaxial layer has a first electrode thereon, an isolation structure is arranged outside the epitaxial structure, and a second electrode is arranged outside the isolation structure; and the second electrode is arranged on both sides of a narrow portion of the hourglass shape. 2.The Micro-LED display panel of claim 1, wherein: when viewed from above, in each LED chip, the substrate layer has a shape with wider ends and a narrower middle, and the narrower portion of the substrate layer forms a concave portion. 3.The Micro-LED display panel of claim 2, wherein: in two adjacent LED chips of different colors in the row direction, one of the LED chips has one corner embedded in the concave portion of the other LED chip. 4.The Micro-LED display panel of claim 1, wherein: in the column direction, two adjacent LED chips of the same color are separated by a barrier wall; and in the row direction, the length of the barrier wall is greater than or equal to the width of each LED chip. 5.The Micro-LED display panel of claim 4, wherein: the height of the barrier wall is greater than the height of each LED chip. ​ ​ ​ ​ ​ ​ ​ ​

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