TW201947736A - Light emitting unit coplanar structure of micro LED display composed of a plurality of light emitting units arranged on a substrate to form an array and having an improved light emitting uniformity - Google Patents

Abstract

This invention discloses a light emitting unit coplanar structure of a micro LED display. The micro LED display is composed of a plurality of light emitting units arranged on a substrate to form an array, and the light emitting units are composed of red, green and blue LED chips on a carrier board. The light emitting units are characterized in that the height of at least one LED chip in the red, green and blue LED chips of the light emitting units is relatively larger than those of the remaining LED chips so that a height difference is formed between the height of the at least one LED chip and the height of the remaining LED chips, wherein a first surface of the carrier board is provided with at least one groove for accommodating the LED chip having a relatively high height, each of the grooves has a depth and the depth is approximately equal to the height difference, whereby the red, green and blue LED chips can form a coplanar state on the carrier board to improve the light emitting uniformity of the micro LED display at different viewing angles.

Description

   Coplanar structure of light-emitting unit of micro-emitting diode display   

The invention relates to a light-emitting unit structure of a micro-light-emitting diode display, and more particularly, to a light-emitting unit having at least one groove in the carrier plate on which red, green, and blue LED chips are arranged for accommodating the red and green. And blue LED chips with relatively large height, thereby enabling the red, green, and blue LED chips to form a coplanar state on the carrier board to improve the uniformity of light emission of the microluminescent diode display at different viewing angles .

Micro LED display is a new generation display technology. Its structure is a miniaturized LED array, that is, a high-density micro-sized LED array integrated on a substrate (chip). Therefore, micro LED technology can be regarded as LED miniaturization and matrix technology, and the structure design of the micro LED display can be regarded as a miniature version of the outdoor LED display, which is to reduce the pixel distance from the millimeter level to the micron level.

Here, FIG. 1 is taken as an example for illustration but is not limited. The micro-light emitting diode (LED) display referred to in the present invention is composed of a plurality of light-emitting units 1 arranged on a substrate (chip) 1a to form an array. The light-emitting unit 1 is constituted by a red LED chip 10, a green LED chip 20, and a blue LED chip 30 arranged and electrically connected on a carrier board 40 as shown in FIG. 1 but not limited. For example, the light-emitting unit The carrier plate 40 of 1 can be further integrated with the substrate 1a of the micro-light-emitting diode display, that is, the red LED chip 10, the green LED chip 20, and the blue LED chip 30 of each light-emitting unit 1 can be directly arranged and electrically connected to each other. The substrate 1a is not limited. In addition, the carrier board 40 has a first surface 41 and an opposite second surface 42 as shown in FIG. 2 but is not limited, and the red, green, and blue LED chips (10, 20, 30) are generally covered with crystal. The package is not limited, so that the first surface (11, 21, 31) of each chip (10, 20, 30) can be electrically connected to each of the predetermined surfaces of the first surface 41 of the carrier board 40. Corresponding positions (10a, 20a, 30a) (as shown in FIG. 1), and each connection line 43 (43a, 43b, 43c) preset by the carrier board 40 is provided without limitation to provide the red and green colors respectively Power required for blue LED chip (10, 20, 30) to emit light.

In terms of the arrangement of the crystal pads (such as P / N poles) on the LED chip, the currently used red, green, and blue LED chips (10, 20, 30) can be divided into vertical chips and horizontal chips, of which vertical Type wafer means that it has at least two crystal pads (such as P / N poles) and is divided on one of the first surface and the opposite second surface of the wafer, and horizontal wafer means that it has at least two crystal pads but the same It is provided on the same surface of the wafer. In addition, in terms of current micro LED chip production technology, although the horizontal chip is favorable for flip-chip packaging operations, the production cost of the horizontal chip is relatively high, which is not conducive to the cost control of the micro-emitting diode (LED) display. In particular, with the existing red, green, and blue LED chips (10, 20, 30), the height of the red LED chip (10) is relatively larger than the height of the green and blue LED chips (20, 30), and the green, blue The height of the LED chip (20, 30) is approximately equal, that is, the relatively large height of the LED chip (such as the red LED chip 10 but not limited) and the remaining LED chips (such as the green and blue LED chips 20, 30 but not limited) A height difference has already formed between the heights; therefore, when the existing red, green, and blue LED chips (10, 20, 30) are packaged on the same plane of the carrier board 40 (or substrate 1a) of the light emitting unit 1, the front side Seeing it (as shown in the front view angle shown in Figure 1), the uniformity of the light emission of the red, green and blue LED chips (10, 20, 30) is not affected, but oblique viewing (slanted as shown in Figure 1) Front view angle), due to the high height of the red LED chip (10), more red light will be seen, which will affect the uniformity of light emission of the light emitting unit.

It can be seen from the above that, for the light-emitting unit of a micro-emitting diode display, how to effectively solve the problem that the red, green, and blue LED chips have different heights that will relatively affect the light-emitting uniformity of the light-emitting unit at an oblique viewing angle is still There is a need for improvement, and the present invention proposes a solution to the above needs.

The main object of the present invention is to provide a co-planar structure of a light emitting unit of a micro LED display, which is provided with at least one groove on a carrier plate of the light emitting unit, so that each groove can accommodate the corresponding groove. Among the red, green, and blue LED chips included in the light-emitting unit are relatively high wafer height LED wafers, wherein each groove has a depth and the depth is approximately equal to the height of the relatively high LED wafers and other wafer heights The relatively low height difference between the LED chips enables the red LED chip, the green LED chip, and the blue LED chip to be mounted on the carrier board of the light-emitting unit or to emit light when the LED chips are on the carrier board. A coplanar state is formed thereon, so that the micro-light-emitting diode display can maintain good light-emitting uniformity at different viewing angles.

In an embodiment of the present invention, in the light emitting unit, the LED chip having a relatively high height is the red LED chip, and other LED chips having a relatively low height are the green LED chip and the blue LED chip.

In an embodiment of the present invention, the green LED chip and the blue LED chip have approximately the same height, so the height of the red LED chip is relatively greater than the height of the green LED chip and the blue LED chip. , So a height difference is formed between the two heights.

In an embodiment of the present invention, a position where the red, green, and blue LED chips are arranged on a first surface of a carrier board of the light-emitting unit is a linear arrangement or an isosceles triangle arrangement.

In an embodiment of the present invention, when the red LED chip, the green LED chip, and the blue LED chip are all horizontal wafers, each wafer has at least two crystal pads and the at least two crystal pads are separately disposed on each wafer. On a first surface, when each chip is mounted on a carrier board of the light-emitting unit in a flip-chip package, each crystal pad provided on the first surface of each chip can be electrically separated by a conductive material. It is connected to each connection line preset on the carrier board.

In an embodiment of the present invention, when the red LED wafer is a vertical wafer and the green LED wafer and the blue LED wafer are horizontal wafers, the red LED wafer has at least two crystal pads, of which at least one crystal pad Is arranged on a first side of the LED chip, and the other at least one crystal pad is arranged on an opposite second side; wherein when each chip is mounted on the carrier board in a flip-chip package, At least one crystal pad on the first surface of the LED chip and each of the crystal pads provided on the first surface of the green LED chip and the blue LED chip can be separately and electrically connected to the carrier board by electrically conductive materials. Each connection line 43, and at least one crystal pad provided on the second surface of the red LED chip is electrically connected to a predetermined one provided on the first surface of the carrier board and located on the outer edge of the groove by a conductive material. Connect the lines.

In an embodiment of the present invention, a groove is provided on the first side of the carrier board of the light-emitting unit for the green LED chip and the blue LED chip at a corresponding position for the green LED chip and the blue LED. The LED chip is placed and forms an electrical connection.

In an embodiment of the present invention, the carrier board of the light-emitting unit is integrated with the substrate of the micro-light-emitting diode display, so that the red, green, and blue LED chips of each light-emitting unit can be directly aligned and electrically connected. The ground is provided on the substrate.

1‧‧‧light-emitting unit

1a‧‧‧ substrate

10‧‧‧Red LED Chip

10a‧‧‧ corresponding position

11‧‧‧ the first side

12‧‧‧ second side

13‧‧‧ crystal pad

14‧‧‧ crystal pad

20‧‧‧Green LED Chip

20a‧‧‧ corresponding position

21‧‧‧ the first side

22‧‧‧Second Side

23‧‧‧ crystal pad

24‧‧‧ crystal pad

30‧‧‧Blue LED Chip

30a‧‧‧ corresponding position

31‧‧‧ the first side

32‧‧‧ second side

33‧‧‧ crystal pad

34‧‧‧ crystal pad

40‧‧‧ Carrier Board

41‧‧‧ the first side

42‧‧‧Second Side

43‧‧‧connection line

43a‧‧‧connection line

43b‧‧‧connection line

43c‧‧‧connection line

44‧‧‧ groove

44a‧‧‧groove

50‧‧‧Conductive material

60‧‧‧protective material

FIG. 1 is a schematic front view of an embodiment of a microluminescent diode display of the present invention.

FIG. 2 is a schematic cross-sectional view of an embodiment of a light emitting unit according to the present invention.

FIG. 3 is a schematic front view of another embodiment of the light emitting unit of the present invention. .

FIG. 4 is a schematic cross-sectional view of the light-emitting unit shown in FIG. 3.

FIG. 5 is a schematic front view of another embodiment of the light emitting unit of the present invention.

FIG. 6 is a schematic cross-sectional view of the light emitting unit shown in FIG. 5.

FIG. 7 is a schematic front view of another embodiment of the light emitting unit of the present invention.

FIG. 8 is a schematic cross-sectional view of the light emitting unit shown in FIG. 7.

In order to make the present invention clearer and more detailed, the preferred embodiments are listed below and the following drawings are used to describe the structure and technical features of the present invention in detail. Each of the drawings is only used to illustrate the structural relationship and related functions of the present invention. Therefore, the size or shape or size of each part is not set according to actual proportions and is not intended to limit the present invention: Referring to FIG. 1, the micro-light emitting diode (LED) display of this embodiment is composed of a plurality of light-emitting units 1 arranged on a substrate ( Chip) 1a and an array is formed, wherein each light-emitting unit 1 (refer to the lower left corner of FIG. 1) is arranged and electrically arranged by a red LED chip 10, a green LED chip 20, and a blue LED chip 30 It is constituted without limitation by being disposed on a carrier board 40, for example, the carrier board 40 of the light-emitting unit 1 can be integrated with the substrate 1a of the micro-light-emitting diode display, that is, the red LED chip of each light-emitting unit 1. 10. The green LED chip 20 and the blue LED chip 30 can be directly arranged and electrically connected to the substrate 1a, but the invention is not limited thereto.

Referring to FIG. 2, the carrier board 40 has a first surface 41 and an opposite second surface 42. The red, green, and blue LED chips 10, 20, and 30 are operated by flip-chip packaging without limitation. The first surfaces 11, 21, and 31 of the red, green, and blue LED chips 10, 20, and 30 can be electrically connected to the corresponding positions 10a, 10a, respectively, which are predetermined on the first surface 41 of the carrier board 40. 20a, 30a (see the light-emitting unit 1 shown in the lower left corner of FIG. 1), and the connection lines 43 (43a, 43b, 43c) preset by the carrier board 40 are shown in FIG. 2 but are not limited The present invention provides the power required for the red, green, and blue LED chips 10, 20, and 30 to emit light, respectively.

The main feature of the light-emitting unit 1 of the present invention is that among the red LED wafer 10, the green LED wafer 20, and the blue LED wafer 30 included in the light-emitting unit 1, there is at least one LED wafer (10) and the wafer it has The height is relatively greater than the height of each of the other LED chips (20, 30).

Here, FIG. 2 is taken as an example for illustration, but is not limited. The LED chip 10 is a red LED chip, and the height of the LED chip 10 is between the first surface 11 and the second surface 12 of the LED chip 10. The distance is relatively larger than the heights of the other LED chips, namely the green LED chip 20 and the blue LED chip 30. Therefore, the height of the relatively large LED chip 10 is the same as that of the other LED chips, namely the green LED chip 20 and the blue LED chip 30. A height difference is formed between the heights. In addition, referring to FIGS. 1 and 2, at least one groove 44 is further provided on the first surface 41 of the carrier plate 40 for inserting and forming LED chips 10 having a relatively high height. Electrically connected, wherein each groove 44 has a depth, and the depth is approximately equal to the height difference, so that the red LED chip 10, the green LED chip 20, and the blue LED chip 30 are packaged in the light emitting unit. After the carrier board 40 of 1 is mounted, each LED chip (10, 20, 30) can form a coplanar state on the carrier board 40. As shown in FIG. 2, each LED chip (10, 20, 30) is flush with A A flat surface, thereby enabling the micro-light emitting diode display to maintain good light emission uniformity at different viewing angles.

The red LED chip 10, the green LED chip 20, and the blue LED chip 30 are disposed at corresponding positions 10a, 20a, and 30a on the first surface 41 of the carrier board 40 of the light emitting unit 1, and a linear arrangement can be formed as shown in FIG. 3 The red LED chip 10 must be located at the top corner of the isosceles triangle, the green LED chip 20 and the blue LED. The wafer 30 must be located at two corners of the isosceles triangle.

Referring to the embodiments shown in FIGS. 1 to 8, among the red LED chip 10, the green LED chip 20, and the blue LED chip 30 included in the light-emitting unit 1, the LED chip 10 having a relatively high height is a red LED chip. The other LED chips 20 and 30 having relatively small heights are the green LED chip 20 and the blue LED chip 30 respectively, but the invention is not limited thereto. In addition, in the embodiments shown in FIGS. 1 to 8, the green LED chip 20 and the blue LED chip 30 have approximately the same height but are not intended to limit the present invention, so the red LED chip 10 The height is relatively larger than the height of the green LED chip 20 and the blue LED chip 30, so the height difference is formed between the two.

Referring to FIGS. 2 and 4, the red LED chip 10, the green LED chip 20, and the blue LED chip 30 are all horizontal wafers, and each wafer (10, 20, 30) has at least two crystal pads (13/14, 23/24, 33/34), the at least two crystal pads (13/14, 23/24, 33/34) are separately provided on the first side (11, 21, 31), wherein when each chip (10, 20, 30) is electrically connected to the carrier board 40 in a flip-chip package, it is provided on the first side of each chip (10, 20, 30) Each crystal pad (13, 14, 23, 24, 33/34) on (11, 21, 31) can be electrically connected to the connection lines preset on the carrier board 40 by the conductive material 50 respectively. 43 (43a, 43b, 43c).

Each connection line 43 (43a, 43b, 43c) preset on the carrier board 40 of the light-emitting unit 1 includes a planar circuit layer, a perforated circuit, or a combination thereof, as shown in Figs. 2, 4, 6, and 8. Since the production of each connection line 43 (43a, 43b, 43c) is made according to design needs using existing technology such as printed circuit board (PCB) manufacturing techniques, it will not be repeated here.

In addition, referring to FIGS. 5-6 or 7-8, when the red LED wafer 10 is a vertical wafer and the green LED wafer 20 and the blue LED wafer 30 are horizontal wafers, the red LED wafer 10 has at least two crystals. At least one of the crystal pads 14 is disposed on the first surface 11 of the LED chip 10, and the other of the at least one crystal pad 13 is disposed on the opposite second surface 12 as shown in FIGS. 6 and 8. Then, when each chip (10, 20, 30) is provided on the carrier board 40 in a flip-chip package and is electrically connected to each other, at least one crystal pad 14 provided on the first surface 11 of the red LED chip 10 and The crystal pads 23 and 24, 33, and 34 provided on the first surfaces 21 and 31 of the green LED chip 20 and the blue LED chip 30 are respectively electrically connected to the carrier board 40 by a conductive material 50 to be electrically connected to the carrier board 40 separately. Each connection line 43 (43a, 43b, 43c) is provided, and at least one crystal pad 13 provided on the second surface 12 of the red LED chip 10 is further electrically connected to the carrier plate 40 provided by a conductive material 50a. The predetermined connection line 43 a is located on the first surface 41 and located on the outer edge of the groove 44.

Referring to FIGS. 7 and 8 again, for design or production needs, a corresponding position 20a, 30a of the green LED chip 20 and the blue LED chip 30 may be provided on the first surface 41 of the carrier board 40, and a groove 44a may be further provided. The green LED chip 20 is inserted into the blue LED chip 30 to form an electrical connection. The groove 44 a functions similarly to the groove 44, and is mainly used to make the red LED chip 10 and the green LED chip 20. After the blue LED chip 30 is packaged on the carrier board 40, each LED chip (10, 20, 30) can form a coplanar state on the carrier board 40. As shown in FIG. 8, each LED chip (10, 20, 30) 30) All are flush with the A plane.

In addition, referring to FIGS. 2, 4, 6, and 8, in order to protect the stability of each LED chip (10, 20, 30) in each groove 44 or 44a, it is necessary to further fill in each groove 44 or 44a. At least one protective material 60.

In addition, for the design or production of the microluminescent diode display, the carrier plate 40 of the light emitting unit 1 may be integrated with the substrate 1a of the microluminescent diode display, that is, the red LED chip 10 of each light emitting unit 1, The green LED chip 20 and the blue LED chip 30 can also be directly arranged and electrically connected to the substrate 1a without using the carrier board 40, but the invention is not limited thereto.

The co-planar structure of the light emitting unit of the micro LED display of the present invention has at least the following advantages compared with the prior art in the art:

(1) In the present invention, the depth of each groove 44 (or 44a) provided on the carrier board 40 (or the substrate 1a) is designed to be approximately equal to that between the LED chips (10, 20, 30). The height difference enables the red LED chip 10, the green LED chip 20, and the blue LED chip 30 to be packaged on the carrier board 40 (or the substrate 1a), and then the LED chips (10, 20, 30) can form a coplanar state. As a result, the micro-luminescent diode display can maintain good uniformity of light emission at different viewing angles.

(2) In the present invention, the technology of providing the groove 44 (or 44a) on the carrier board 40 (or the substrate 1a), regardless of the structure type of the red, green, and blue LED chips (10, 20, 30) used is Both vertical and horizontal wafers are applicable, which is beneficial to the manufacturing side's choice of the red, green, and blue LED wafer (10, 20, 30) structure types and effectively reduces costs.

(3) The technology for providing a recess 44 (or 44a) on the carrier board 40 (or substrate 1a) of the present invention is not only sufficient to solve the problem that the LED chips (10, 20, 30) of the prior art cannot form a coplanar surface, and Does not affect the original packaging process.

The above descriptions are merely preferred embodiments of the present invention, and are only illustrative, not restrictive, for those skilled in the art. Those skilled in the art understand that they can be modified within the spirit and scope defined by the claims of the present invention. Many changes, modifications, and even equivalent changes will be made, but all will fall into the protection scope of the present invention.

Claims (10)

    A co-planar structure of a light emitting unit of a micro LED display, wherein the micro light emitting diode display is formed by arranging a plurality of light emitting units on a substrate to form an array, wherein the light emitting unit is composed of The red LED chip, the green LED chip, and the blue LED chip are arranged and electrically connected to each other on a carrier board. The carrier board has a first surface and an opposite second surface. The red LED chip, the green LED The chip and the blue LED chip are packaged in flip-chip mode so that the first side of each LED chip is electrically connected to each of the predetermined corresponding positions on the first side of the carrier board, and the carrier board The preset connection lines respectively provide the power required for the red LED chip, the green LED chip, and the blue LED chip to emit light; the light-emitting unit is characterized in that the red LED chip and the green LED chip included in the light-emitting unit And the height of at least one LED chip in the blue LED chip is relatively larger than the height of the remaining LED chips, so that a height difference is formed between the height of each LED chip having a relatively large height and the height of the remaining LED chips; In the On the first side of the carrier board, a groove is provided at each corresponding position of each LED chip having a relatively high height, and each LED chip having a relatively high height is inserted and formed into an electrical connection, wherein each groove has A depth and the depth is approximately equal to the height difference, so that when the red LED chip, the green LED chip, and the blue LED chip emit light, the second surface of each LED chip can form a coplanar state.         The co-planar structure of the light-emitting unit of the micro-emitting diode display according to claim 1, wherein the relatively large LED chip is the red LED chip, and the other LED chips are the green LED chip and the blue LED chip. .         The co-planar structure of the light-emitting unit of the micro-emitting diode display as described in claim 2, wherein the green LED chip and the blue LED chip have approximately the same height, so the height of the red LED chip is relatively greater than The heights of the green LED chip and the blue LED chip thus form the height difference between the two.         The co-planar structure of the light-emitting unit of the micro-emitting diode display according to claim 2, wherein the positions where the red LED chip, the green LED chip, and the blue LED chip are disposed on the first surface of the carrier board form a linear arrangement Or, an isosceles triangle arrangement. When an isosceles triangle arrangement is formed, the red LED chip is located at the top corner of the isosceles triangle and the green LED chip and the blue LED chip are located at the two corners of the isosceles triangle.         The co-planar structure of the light emitting unit of the micro-emitting diode display according to claim 2, wherein when the red LED chip, the green LED chip, and the blue LED chip are all horizontal wafers, each wafer has at least two crystal pads. And the at least two crystal pads are separately provided on the first surface of each LED chip, and when each LED chip is electrically connected to the carrier board in a flip-chip manner, the first wafer is provided on the first surface of each LED chip. Each crystal pad on the surface can be separately and electrically connected to each connection line preset on the carrier board by a conductive material.         The co-planar structure of the light-emitting unit of the micro-emitting diode display according to claim 2, wherein the red LED chip is a red LED chip when the red LED chip is a vertical chip and the green LED chip and the blue LED chip are horizontal chips. There are at least two crystal pads and at least one crystal pad is disposed on the first surface of the red LED chip, and the other at least one crystal pad is disposed on the opposite second surface of the red LED chip; When provided on the carrier board in a flip-chip manner, at least one crystal pad provided on the first surface of the red LED chip and each of the green LED chip and the blue LED chip on the first surface are electrically connected. The crystal pad can be electrically connected to each of the connection lines preset on the carrier board by a conductive material separately, and at least one crystal pad provided on the second surface of the red LED chip is electrically connected to the carrier board by a conductive material. It is arranged on the first surface of the carrier board and is located on a predetermined connection line on the outer edge of the groove.         The light-emitting unit of the micro-light-emitting diode display according to claim 1 has a coplanar structure, wherein each connection line preset on the carrier board includes a flat-type circuit layer, a perforated line, or a combination thereof.         The co-planar structure of the light-emitting unit of the micro-light-emitting diode display according to claim 2, wherein a groove is further provided on the first surface of the carrier board at a position corresponding to the green LED chip and the blue LED chip. The green LED chip and the blue LED chip are respectively placed and electrically connected.         The co-planar structure of the light-emitting unit of the micro-luminescent diode display according to claim 1, wherein each of the grooves is further filled with at least one protective material.         The light-emitting unit of the micro-light-emitting diode display according to claim 1 has a coplanar structure, wherein the carrier plate of the light-emitting unit 1 is integrated with the substrate of the micro-light-emitting diode display.