TWI866601B - Light emitting unit - Google Patents

Abstract

A light emitting unit includes a redistribution layer (RDL) and a plurality of micro light emitting elements. The RDL includes a plurality of electrode patterns, a plurality of pad patterns, an insulating layer and a plurality of conductive through holes. A first gap and a second gap are respectively provided between two adjacent electrode patterns and between corresponding two adjacent pad patterns. A third length of the overlapping area of an orthographic projection of the first gap on the pad patters and the pad patters in a first direction is less or equal to a second length of the second gap in the first direction. The micro light emitting elements are disposed on the RDL and electrically connected with the electrode patterns.

Description

Luminescent display unit

The present invention relates to a self-luminous display technology, and in particular to a luminous display unit.

After the micro-LED display unit is transferred from the epitaxial substrate to the film layer (such as blue film), during the process of using the ejector needle to pick up the parts (such as visual inspection (Sorting) and bonding (Bonding)), the micro-LED display unit without a transparent hard substrate (such as a glass substrate or a sapphire substrate) for protection will bend on the film layer. In addition, because some areas of the micro-LED display unit do not have a metal layer but only an insulating layer, the micro-LED display unit has insufficient support strength and cracks, which in turn affects the overall structural reliability and yield.

The present invention provides a light-emitting display unit that can avoid splitting to improve yield and has better structural reliability.

The present invention also provides a display device, which includes the above-mentioned light-emitting display unit and can have a better display yield.

The light-emitting display unit of the present invention includes a redistribution wiring layer and a plurality of micro-light-emitting elements. The redistribution wiring layer includes a plurality of electrode patterns, a plurality of pad patterns, an insulating layer and a plurality of conductive vias. The insulating layer is disposed between the electrode pattern and the pad pattern. The conductive via is disposed in the insulating layer and electrically connects the electrode pattern and the corresponding pad pattern. The electrode patterns are electrically independent of each other. There is a first gap and a second gap between two adjacent electrode patterns and between two corresponding adjacent pad patterns, respectively. The first gap and the second gap have a first length and a second length, respectively, in a first direction. A third length of the orthographic projection of the first gap on the pad pattern and the overlapping area of the pad pattern in the first direction is less than or equal to the second length of the second gap in the first direction. The micro-light-emitting element is arranged on the redistribution wiring layer and is electrically connected to the electrode pattern.

The light-emitting display unit of the present invention includes a redistribution wiring layer and a plurality of micro-light-emitting elements. The redistribution wiring layer includes a plurality of electrode patterns, a plurality of pad patterns, an insulating layer and a plurality of conductive vias. The insulating layer is disposed between the electrode pattern and the pad pattern. The conductive via is disposed in the insulating layer and electrically connects the electrode pattern with the corresponding pad pattern. The micro-light-emitting elements are disposed on the redistribution wiring layer and electrically connected to the electrode pattern. Part of the insulating layer is exposed between the micro-light-emitting elements. The light-emitting display unit has a first length in a first direction, and the insulating layer exposed between the micro-light-emitting elements has a second length in the first direction that is less than 50% of the first length. In the first direction, the insulating layer overlaps at least one of the electrode pattern and the pad pattern from a center line to an edge of the light-emitting display unit.

The display device of the present invention includes a driving substrate and a plurality of light-emitting display units. The driving substrate includes a plurality of pads. The light-emitting display units are electrically connected to the driving substrate through the pads, and each light-emitting display unit includes a redistribution wiring layer and a plurality of micro light-emitting elements. The redistribution wiring layer includes a plurality of electrode patterns, a plurality of pad patterns, an insulating layer and a plurality of conductive vias. The insulating layer is disposed between the electrode pattern and the pad pattern. The conductive via is disposed in the insulating layer and electrically connects the electrode pattern and the corresponding pad pattern. The electrode patterns are electrically independent of each other. There is a first gap and a second gap between two adjacent electrode patterns and between two corresponding adjacent pad patterns. The first gap and the second gap have a first length and a second length in a first direction, respectively. A third length in the first direction of the orthographic projection of the first gap on the pad pattern and the overlapping area of the pad pattern is less than or equal to the second length of the second gap in the first direction. The micro-luminescent element is arranged on the redistribution wiring layer and is electrically connected to the electrode pattern.

Based on the above, in the design of the light-emitting display unit of the present invention, there is a first gap and a second gap between two adjacent electrode patterns and between two corresponding adjacent pad patterns, and the first gap and the second gap have a first length and a second length in the first direction, respectively, wherein the third length of the orthographic projection of the first gap on the pad pattern and the overlapping area of the pad pattern in the first direction is less than or equal to the second length of the second gap in the first direction. With this design, the gaps between the electrode pattern and the pad pattern can be staggered, which can effectively avoid splitting, so as to improve the yield, so that the light-emitting display unit of the present invention can have better structural reliability. In addition, the display device including the light-emitting display unit of the present invention can have a better display yield.

In order to make the above features and advantages of the present invention more clearly understood, the following is a detailed description of the embodiments with the accompanying drawings.

10: Display device

100a, 100b: luminous display unit

110: Re-layout wiring layer

112a, 112b, 113: Electrode pattern

114a, 114b, 115: pad pattern

116: Insulation layer

118: Conductive vias

120: Micro light-emitting element

122: First color micro-luminescent element/red micro-luminescent element

124: First color micro-luminescent element/green micro-luminescent element

126: Second color micro-luminescent element/blue micro-luminescent element

130: Packaging colloid

200: Drive substrate

201: Upper surface

202: Lower surface

210:Pad

300: Driving circuit components

A1: First electrode pattern

A2: Second electrode pattern

A3: Third electrode pattern

B1: First pad pattern

B2: Second pad pattern

B3: Third pad pattern

C: Center line

D1: First direction

D2: Second direction

E1, L1, L1’: first length

E2, L2, L2’: Second length

G1, G1’: First gap

G2, G2’: The second gap

H1, W1: First distance

H2, W2: Second distance

L3, L3’: The third length

L4, L4’: the fourth length

P1: First spacing

P2: Second spacing

S1, S2: Edge

T:Thickness

T1: First thickness

T2: Second thickness

T3: The third thickness

W: Width

FIG1A is a top perspective schematic diagram of a light-emitting display unit according to an embodiment of the present invention.

Figure 1B is a schematic cross-sectional view along line I-I of Figure 1A.

Figure 2 is a top perspective schematic diagram of a light-emitting display unit according to another embodiment of the present invention.

Figure 3 is a schematic diagram of a display device according to an embodiment of the present invention.

FIG. 1A is a top perspective schematic diagram of a light-emitting display unit according to an embodiment of the present invention. FIG. 1B is a cross-sectional schematic diagram along line I-I of FIG. 1A. For the sake of clarity, the conductive vias of the redistribution wiring layer are omitted in FIG. 1A.

Please refer to FIG. 1A and FIG. 1B at the same time. In this embodiment, the light-emitting display unit 100a includes a redistribution wiring layer 110 and a plurality of micro-light-emitting elements 120. The redistribution wiring layer 110 includes a plurality of electrode patterns 112a, a plurality of pad patterns 114a, an insulating layer 116, and a plurality of conductive vias 118. The insulating layer 116 is disposed between the electrode pattern 112a and the pad pattern 114a. The conductive via 118 is disposed in the insulating layer 116 and electrically connects the electrode pattern 112a and the corresponding pad pattern 114a. The electrode patterns 112a are electrically independent of each other. There is a first gap G1 and a second gap G2 between two adjacent electrode patterns 112a and between two corresponding adjacent pad patterns 114a. The first gap G1 and the second gap G2 have a first length L1 and a second length L2 in a first direction D1, respectively. A third length L3 of the orthogonal projection of the first gap G1 on the pad pattern 114a and the overlapping area of the pad pattern 114a in the first direction D1 is less than or equal to the second length L2 of the second gap G2 in the first direction D1. A fourth length L4 of the orthogonal projection of the second gap G2 on the electrode pattern 112a and the overlapping area of the electrode pattern 112a in the first direction D1 is less than or equal to the first length L1 of the first gap G1 in the first direction D1. These micro-light-emitting elements 120 are disposed on the redistribution circuit layer 110 and are electrically connected to the electrode pattern 112a.

Specifically, in this embodiment, the electrode pattern 112a of the redistribution circuit layer 110 may be located above the pad pattern 114a. In one embodiment, the electrode pattern 112a is disposed on the top surface of the insulating layer 116, and one side of the pad pattern 114a may be aligned with the bottom surface of the insulating layer 116, that is, the pad pattern 114a is buried in the insulating layer 116, and a solder mask layer (not shown) is subsequently disposed on the bottom surface of the insulating layer 116 to have a smoother surface, but the present invention is not limited thereto. The electrode pattern 112a can be electrically connected to the corresponding pad pattern 114a through the conductive via 118 extending from the top surface of the insulating layer 116 to the pad pattern 114a. In other words, the upper layer of the redistribution wiring layer 110 is the electrode pattern 112a, and the lower layer is the pad pattern 114a. The material of the electrode pattern 112a and the material of the pad pattern 114a can be, for example, copper, and the material of the insulating layer 116 can be, for example, an organic insulating material or an inorganic insulating material, but is not limited thereto. The number of these micro-luminescent elements 120 is, for example, three, and they are arranged on the redistribution wiring layer 110 at intervals along the second direction D2 perpendicular to the first direction D1. In one embodiment, the micro-luminescent elements 120 may include red micro-luminescent elements 122, green micro-luminescent elements 124, and blue micro-luminescent elements 126, but are not limited thereto. One end of each of these micro-luminescent elements 120 is electrically connected to the electrode pattern 112a, and the other end of each of these micro-luminescent elements 120 is electrically connected to the electrode pattern 113. In other words, the light-emitting display unit 100a can be a common cathode design. The electrode pattern 113 is also electrically connected to the two pad patterns 115 below through the conductive via 118.

Please refer to FIG. 1A and FIG. 1B together. Part of the insulating layer 116 is exposed between these micro-light-emitting elements 120. In detail, the light-emitting display unit 100a has a first length E1 in the first direction D1, and a second length E2 of the insulating layer 116 exposed between the micro-light-emitting elements 120 in the first direction D1 is less than 50% of the first length E1. In a top view, in the first direction D1, the insulating layer 116 overlaps with at least one of the electrode pattern 112a and the pad pattern 114a from a center line C to an edge S1 of the light-emitting display unit 100a. In other words, the insulating layer 116 does not appear to be continuously exposed from the center line C to the edge S1. More specifically, the insulating layer 116 exposed between the micro-light-emitting elements 120 will not be continuously exposed.

Furthermore, the light-emitting display unit 100a of the present embodiment further includes a packaging resin 130, wherein the packaging resin 130 is disposed on the redistribution wiring layer 110 and covers the micro-light-emitting element 120. Here, the material of the packaging resin 130 is, for example, an organic polymer, acrylic or resin. The ratio of the thickness T (including the third thickness T3 of the insulating layer 116 plus the thickness of the packaging resin 130) to the width W (here, the width of the insulating layer 116 in the second direction D2) of the light-emitting display unit 100a is between 0.3 and 1. The width W mentioned here refers to the maximum width. In one embodiment, the width W may be, for example, 270 microns to 330 microns, but is not limited thereto. In one embodiment, the thickness T is, for example, 100 microns, and the width W is, for example, 300 microns, but not limited thereto. In cross-section, the electrode pattern 112a has a first thickness T1, the pad pattern 114a has a second thickness T2, and the insulating layer 116 has a third thickness T3. The first thickness T1 and the second thickness T2 are respectively less than the third thickness T3, and preferably, the ratio of the first thickness T1 or the second thickness T2 to the third thickness T3 is greater than 0.3 and less than or equal to 0.5. In one embodiment, the first thickness T1, the second thickness T2, and the third thickness T3 may be, for example, all less than 10 microns. In one embodiment, the first thickness T1 may be, for example, 4 microns, the second thickness T2 may be, for example, 3 microns, and the third thickness T3 may be, for example, 9 microns. Since the light-emitting display unit 100a is too wide and thin, the thin light-emitting display unit 100a is easily bent and broken during the pin manufacturing process, and the micro-light-emitting elements are arranged on the redistribution wiring layer 110 at intervals along the second direction D2, resulting in the insulation layer exposed in the middle being easily split because the redistribution wiring layer 110 cannot support these micro-light-emitting elements 120. Therefore, the yield is improved by strengthening the structural strength of the redistribution wiring layer 110.

In addition, please refer to FIG. 1A and FIG. 1B at the same time. In this embodiment, the electrode pattern 112a includes a first electrode pattern A1, a second electrode pattern A2, and a third electrode pattern A3 that are separated from each other. The pad pattern 114a includes a first pad pattern B1, a second pad pattern B2, and a third pad pattern B3 that are separated from each other. The orthographic projection of the second electrode pattern A2 on the pad pattern 114a overlaps the first pad pattern B1, the second pad pattern B2, and the third pad pattern B3. That is, the orthographic projection of the second electrode pattern A2 on the pad pattern 114a extends from the second pad pattern B2 to overlap the first pad pattern B1 and the third pad pattern B3, and can cover the second gap G2 between the first pad pattern B1 and the second pad pattern B2 and between the second pad pattern B2 and the third pad pattern B3. Preferably, the ratio of the overlapping area of the orthographic projection of the second electrode pattern A2 on the pad pattern 114a and the first pad pattern B1 or the third pad pattern B3 to the area of the first pad pattern B1 or the third pad pattern B3 is less than 0.1. That is, the ratio of the overlapping area of the orthographic projection of the second electrode pattern A2 on the pad pattern 114a and the first pad pattern B1 to the area of the first pad pattern B1 is less than 0.1, and the ratio of the overlapping area of the orthographic projection of the second electrode pattern A2 on the pad pattern 114a and the third pad pattern B3 to the area of the third pad pattern B3 is less than 0.1. On the other hand, the orthographic projections of the first gap G1 between the first electrode pattern A1 and the second electrode pattern A2 and between the second electrode pattern A2 and the third electrode pattern A3 on the pad pattern 114a are also covered by the first pad pattern B1 and the third pad pattern B3, respectively.

In short, since the electrode pattern 112a and the pad pattern 114a of the redistribution circuit layer 110 of the present embodiment are arranged in an overlapping manner, the first gap G1 of the upper electrode pattern 112a and the second gap G2 of the lower pad pattern 114a are staggered, that is, the orthographic projections do not overlap, and the orthographic projection of the first gap G1 overlaps the pad pattern 114a (that is, the first pad pattern B1 and the third pad pattern B3), and the orthographic projection of the second gap G2 overlaps the electrode pattern 112a (that is, the second electrode pattern A2), that is, the orthographic projection of the gap can overlap the electrode pattern 112a or the pad pattern 114a. In this way, the structural strength of the redistribution wiring layer 110 can be enhanced to improve the yield rate, so as to improve and avoid the problem of splitting caused by the ejection process in the prior art, and there is no need to set up a transparent hard material for protection, which can effectively reduce the process and manufacturing costs. Therefore, the light-emitting display unit 100a of this embodiment can have better structural reliability.

It must be noted here that the following embodiments use the component numbers and some contents of the previous embodiments, wherein the same numbers are used to represent the same or similar components, and the description of the same technical contents is omitted. For the description of the omitted parts, please refer to the previous embodiments, and the following embodiments will not be repeated.

FIG. 2 is a schematic top perspective view of a light-emitting display unit according to another embodiment of the present invention. For the sake of clarity, the conductive vias of the redistribution wiring layer are also omitted in FIG. 2. Please refer to FIG. 1A and FIG. 2 at the same time. The light-emitting display unit 100b of this embodiment is similar to the light-emitting display unit 100a of FIG. 1A. The difference between the two is that: in this embodiment, due to different electrical requirements, the top view shape of the electrode pattern 112b of this embodiment is different from the top view shape of the electrode pattern 112a in FIG. 1A. Also because the design of the electrode pattern 112b is different from the electrode pattern 112a, the top view shape of the first gap G1' of this embodiment (such as a Z shape) is different from the top view shape of the first gap G1 (such as a straight line). The third length L3' of the orthographic projection of the first gap G1' on the pad pattern 114b and the overlapping area of the pad pattern 114b in the first direction D1 is less than the second length L2' of the second gap G2' in the first direction D1. The fourth length L4' of the orthographic projection of the second gap G2' on the electrode pattern 112b and the overlapping area of the electrode pattern 112b in the first direction D1 is less than the first length L1' of the first gap G1' in the first direction D1. In one embodiment, the third length L3' may be less than 80% of the second length L2', preferably less than 50%, and the fourth length L4' may be less than 80% of the first length L1', preferably less than 50%.

Furthermore, in this embodiment, the micro-luminescent element 120 includes a plurality of first-color micro-luminescent elements 122 (or 124) and a second-color micro-luminescent element 126. The distance between two adjacent first-color micro-luminescent elements 122 (or 124) is a first distance P1, and the second-color micro-luminescent element 126 has a second distance P2 with the adjacent first-color micro-luminescent element 122 (or 124), and the second distance P2 is greater than the first distance P1. In other words, the distance between micro-luminescent elements 120 of the same color light (i.e., the first distance P1) is smaller than the distance between micro-luminescent elements 120 of different colors (i.e., the second distance P2). The distance described here refers to the minimum distance. In one embodiment, the first color micro-luminescent element 122 may be, for example, a red micro-luminescent element, or the first color micro-luminescent element 124 may be, for example, a green micro-luminescent element, and the second color micro-luminescent element 126 may be, for example, a blue micro-luminescent element. Here, the micro-luminescent element 120 includes two red micro-luminescent elements 122, one blue micro-luminescent element 126, and two green micro-luminescent elements 124, wherein the blue micro-luminescent element 126 is located between the red micro-luminescent element 122 and the green micro-luminescent element 124. The symmetrical configuration can reduce the design complexity of the corresponding electrode pattern 112b.

In addition, please refer to FIG. 2 again. In this embodiment, the insulating layer 116 has a width W in the second direction D2 perpendicular to the first direction D1, and the electrode pattern 112b is retracted by a first distance W1 relative to the insulating layer 116 in the second direction D2, and the pad pattern 114b is retracted by a second distance W2 relative to the insulating layer 116 in the second direction D2. Preferably, the ratio of the first distance W1 to the width W and the ratio of the second distance W2 to the width W can be, for example, between 0.05 and 0.15, respectively. If the above ratio is too small, it is not conducive to the bonding yield of the micro-light-emitting element 120 and the electrode pattern 112b, and the pad pattern 114b and the subsequent driver substrate; on the contrary, if the above ratio is too large, when bonding with the driver substrate, if the cutting tolerance causes the side wall of the pad pattern 114b to be exposed (i.e., not covered by the insulating layer 116), the solder bump will be squeezed onto the electrode pattern 112b due to heat pressing, resulting in a short circuit. In one embodiment, the first distance W1 and the second distance W2 can be, for example, 20 meters to 30 microns, respectively. In one embodiment, the first distance W1 and the second distance W2 may be different. For example, the first distance W1 may be greater than the second distance W2, so as to avoid short circuits caused by cutting tolerances during subsequent punching.

In addition, please refer to FIG. 2 again. The two adjacent pad patterns 114b and 115 arranged in the first direction D1 have a first distance H1 and a second distance H2, wherein the first distance H1 is closer to the edge S2 of the insulating layer 116 relative to the second distance H2, and the first distance H1 is greater than the second distance H2. With this design, a portion of space can be reserved to prevent and retain the solder bumps that are squeezed onto the insulating layer 116 due to subsequent thermal compression bonding, which can effectively improve the structural reliability of the light-emitting display unit 100b.

FIG3 is a schematic diagram of a display device according to an embodiment of the present invention. Referring to FIG3, in this embodiment, the display device 10 includes a driving substrate 200 and a plurality of light-emitting display units 100a as shown in FIG1B above, wherein the light-emitting display unit 100a is electrically connected to the upper surface 201 of the driving substrate 200. Specifically, the driving substrate 200 includes a plurality of pads 210 separated from each other, and the pad pattern 114a of the redistribution wiring layer 110 of each light-emitting display unit 100a is electrically connected to the driving substrate 200 through the pads 210. Each pixel in the pixel area of the display device 10 is formed by a light-emitting display unit 100a. In addition, the display device 10 of this embodiment further includes a driving circuit element 300, which is disposed on the lower surface 202 of the driving substrate 200 relatively far away from the light-emitting display unit 100a and is electrically connected to the driving substrate 200 to control multiple light-emitting display units to form a display screen.

It is worth mentioning that in other embodiments not shown, the light-emitting display unit can include at least any one of the light-emitting display units 100a and 100b according to the needs, and the present invention is not limited. In other words, the number of light-emitting display units can be one or more, and can be the same structure or different structures, which can be selected according to the needs. In addition, the driving substrate 200 of the present embodiment can be, for example, a complementary metal-oxide-semiconductor (CMOS) substrate, a liquid crystal on silicon (LCOS) substrate, a thin film transistor (TFT) substrate, a printed circuit board (PCB) or other substrates with working circuits, which are not limited here.

In summary, in the design of the light-emitting display unit of the present invention, there is a first gap and a second gap between two adjacent electrode patterns and between two corresponding adjacent pad patterns, and the first gap and the second gap have a first length and a second length in the first direction, respectively, wherein the third length of the orthographic projection of the first gap on the pad pattern and the overlapping area of the pad pattern in the first direction is less than or equal to the second length of the second gap in the first direction. With this design, the gaps between the electrode pattern and the pad pattern can be staggered, which can effectively avoid splitting, so as to improve the yield, so that the light-emitting display unit of the present invention can have better structural reliability. In addition, the display device including the light-emitting display unit of the present invention can have a better display yield.

Although the present invention has been disclosed as above by the embodiments, it is not intended to limit the present invention. Any person with ordinary knowledge in the relevant technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope of the attached patent application.

100a: Luminous display unit

110: Re-layout wiring layer

112a: Electrode pattern

114a:Pad pattern

116: Insulation layer

118: Conductive vias

120: Micro light-emitting element

122: First color micro-luminescent element/red micro-luminescent element

124: First color micro-luminescent element/green micro-luminescent element

126: Second color micro-luminescent element/blue micro-luminescent element

130: Packaging colloid

A1: First electrode pattern

A2: Second electrode pattern

A3: Third electrode pattern

B1: First pad pattern

B2: Second pad pattern

B3: Third pad pattern

G1: First gap

G2: Second gap

T:Thickness

T1: First thickness

T2: Second thickness

T3: The third thickness

W: Width

Claims (1)

A light-emitting display unit comprises: A redistribution wiring layer, comprising a plurality of electrode patterns, a plurality of pad patterns, an insulating layer and a plurality of conductive vias, wherein the insulating layer is disposed between the electrode patterns and the pad patterns, and the conductive vias are disposed in the insulating layer and electrically connect the electrode patterns and the corresponding pad patterns; and A plurality of micro-luminescent elements are arranged on the redistribution wiring layer and electrically connected to the electrode patterns, and a portion of the insulating layer is exposed between the micro-luminescent elements, wherein the light-emitting display unit has a first length in a first direction, and a second length of the insulating layer exposed between the micro-luminescent elements in the first direction is less than 50% of the first length, and in the first direction, the insulating layer overlaps with at least one of the electrode patterns and the pad patterns from a center line to an edge of the light-emitting display unit.