TWI889459B - Micro light-emitting diode display panel - Google Patents

Abstract

A micro light-emitting diode (micro-LED) display panel including a substrate, a first light blocking layer, a second light blocking layer, and a plurality of micro-LEDs is provided. The first light blocking layer is disposed on the substrate. The second light blocking layer is disposed on the first light blocking layer. The second light blocking layer defines a plurality of pixel units arranged in an array. The micro-LEDs are disposed on the first blocking layer. At least one of the micro-LEDs is disposed on each of the pixel units. A gap exists between a part of the second light blocking layer and the first light blocking layer. A filling structure is in the gap. A material of the filling structure is different from a material of the second light blocking layer.

Description

Micro LED Display Panel

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

With the advancement of display technology, micro-LED display panels have been developed. In addition to using multiple red micro-LED chips, multiple green micro-LED chips, and multiple blue micro-LED chips in an alternating arrangement to form a color screen, another type of micro-LED display panel uses a plane layer formed on the display backplane and a baffle formed on the plane to form multiple pixel spaces, wherein the micro-LED chips are arranged in the pixel space. Then, a wavelength conversion material is filled in the pixel space to convert the color of the light emitted by the LED chip into another color, so that a color screen can also be formed.

When manufacturing a structure for accommodating wavelength conversion materials, the planar layer and the baffle can be formed separately by lithography process. However, due to the instability of the process, there are gaps at the bottom of the planar layer and the baffle. The gaps will cause the wavelength conversion material to overflow to other pixels through the gaps when the wavelength conversion material is subsequently injected into the pixel space. This can easily cause color crosstalk between adjacent pixels or cause the micro-LED display panel to produce impure color output.

The present invention provides a micro-LED display panel, which can effectively improve the problem of color crosstalk between adjacent pixels.

An embodiment of the present invention provides a micro-LED display panel, comprising a substrate, a first light-shielding layer, a second light-shielding layer and a plurality of micro-LEDs. The first light-shielding layer is disposed on the substrate, and the second light-shielding layer is disposed on the first light-shielding layer, wherein the second light-shielding layer defines a plurality of pixel units arranged in an array. These micro-LEDs are arranged on the first light-shielding layer, wherein at least one of these micro-LEDs is disposed in each pixel unit. There is a gap between a portion of the second light-shielding layer and the first light-shielding layer, and a filling structure is provided in the gap, and the material of the filling structure is different from the material of the second light-shielding layer.

In the micro-LED display panel of the embodiment of the present invention, since a filling structure is used to fill the gap to repair the defect of the gap, when the wavelength conversion material is subsequently injected into the pixel unit, the wavelength conversion material will not overflow to the adjacent pixel unit through the gap to cause the problem of color crosstalk. Therefore, the micro-LED display panel of the embodiment of the present invention can achieve color output with higher color purity.

1A to 1C are partial cross-sectional schematic diagrams for illustrating the manufacturing process of a micro-LED display panel of an embodiment of the present invention. Referring to FIG. 1A to 1C, the micro-LED display panel 100 of the present embodiment includes a substrate 110, a first light shielding layer 120, a second light shielding layer 130 and a plurality of micro-LEDs 140. The first light shielding layer 120 is disposed on the substrate 110, the second light shielding layer 130 is disposed on the first light shielding layer 120, and the second light shielding layer 130 exposes a portion of the first light shielding layer 120, wherein the second light shielding layer 130 defines a plurality of pixel units U arranged in an array. The micro-LEDs 140 are disposed on the first light shielding layer 120 , wherein each pixel unit U is provided with at least one of the micro-LEDs 140 ( FIGS. 1A to 1C take one as an example).

In this embodiment, the substrate 110 is, for example, a circuit backplane, which may be a glass or plastic substrate with conductive circuits disposed thereon, or a silicon substrate with conductive circuits disposed thereon.

There is a gap G between a portion of the second light shielding layer 130 and the first light shielding layer 120, and a filling structure 150 is provided in the gap G. The material of the filling structure 150 is different from the material of the second light shielding layer 130. In the present embodiment, the material of the first light shielding layer 120 and the second light shielding layer 130 is, for example, a resin or a polymer material, which is suitable for a lithography process. In some embodiments, the material of the first light shielding layer 120 and the second light shielding layer 130 is, for example, a light-absorbing resin material, or a light-reflecting resin material. The filling structure 150 is, for example, formed by solidifying transparent ink, and the material of the filling structure 150 is, for example, acrylic polymer, or the material of the filling structure 150 can also be formed by mixing titanium dioxide or zirconium dioxide nanoparticles in acrylic polymer, so that the filling structure 150 also has a light scattering effect.

In the manufacturing process of the micro-LED display panel 100 of the present embodiment, after the micro-LED 140 is disposed on the substrate 110 and the first light shielding layer 120 and the second light shielding layer 130 are manufactured on the substrate 110 by a lithography process, a defect such as a gap G may be generated between a portion of the second light shielding layer 130 and the first light shielding layer 120. Therefore, as shown in FIG1A , the material of the filling structure 150 is filled into a pixel unit U (such as the middle pixel unit U in FIG1A ). The material of the filling structure 150 overflows into the adjacent pixel units U (such as the two pixel units U on the left and right of FIG1A ) through the gap G, and the material of the filling structure 150 fills the gap. Since the filling structure 150 is formed by, for example, solidifying transparent ink, even if it overflows to the adjacent pixel unit U through the gap G, it will not cause adverse effects on the color purity of the adjacent pixel unit U. Then, after the material of the filling structure 150 is cured by light or heat, or after the material of the filling structure 150 is naturally cured, the filling structure 150 can repair the defect of the gap G. In this way, when the wavelength conversion material 160 is filled in a pixel unit U (such as the pixel unit U on the left in FIG. 1B ) as shown in FIG. 1B , the wavelength conversion material 160 will not overflow to the adjacent pixel unit U through the gap G.

In the present embodiment, at least one pixel unit U is provided with a wavelength conversion material 160, and FIG. 1C takes the pixel unit U on the left as an example in which the wavelength conversion material 160 is provided, and the other pixel units U may be provided with a flattening layer 170. The material of the flattening layer 170 may be a transparent material, or may be a material formed by mixing scattering particles in a transparent material, wherein the scattering particles may scatter the light emitted by the micro-LED 140 to achieve a wider viewing angle. The wavelength conversion material 160 is, for example, a quantum dot material, or a fluorescent powder. In the present embodiment, the micro-LED 140 is a micro-LED chip, which may be divided into a blue light micro-LED 140b and a green light micro-LED 140g. In addition, the wavelength conversion material 160 is, for example, a red quantum dot material, which can convert the blue light emitted by the blue micro-LED 140b into red light to form a red sub-pixel (i.e., the pixel unit on the left of FIG. 1C ). In the pixel unit U in the middle of FIG. 1C , the green light emitted by the green micro-LED 140g penetrates the planarization layer 170 to form a green sub-pixel. In the pixel unit U on the right of FIG. 1C , the blue light emitted by the blue micro-LED 140b penetrates the planarization layer 170 to form a blue sub-pixel. FIG. 1C shows a partial cross-sectional view of the micro-LED display panel 100. In practice, the micro-LED display panel 100 may include more red sub-pixels, green sub-pixels, and blue sub-pixels that are alternately arranged, thereby forming a color image.

In another embodiment, in the space of the pixel unit U not filled with the wavelength conversion material 160 (such as the two pixel units U in the middle and on the right of FIG. 1C ), the planarization layer 170 may not be filled. In other words, the planarization layer 170 may be selectively used, that is, the planarization layer 170 is not necessarily used.

In the present embodiment, the filling structure 150 extends to at least one pixel unit U adjacent to the gap G, and is disposed on a peripheral surface 142 of the micro-LED 140 in at least one pixel unit U adjacent to the gap G. In addition, in the present embodiment, the filling structure 150 is further disposed on a top surface 144 of the micro-LED 140 in at least one pixel unit U adjacent to the gap G, so as to serve as a flat layer or a protective layer above the micro-LED 140 for subsequently filling the wavelength conversion material 160 in the space of the pixel unit U.

In the micro-LED display panel 100 of the present embodiment, since the filling structure 150 is used to fill the gap G to repair the defect of the gap G, when the wavelength conversion material 160 is subsequently injected into the pixel unit U, the wavelength conversion material 160 will not overflow to the adjacent pixel unit U through the gap G to cause the problem of color crosstalk. Therefore, the micro-LED display panel 100 of the present embodiment can achieve color output with higher color purity.

FIG2 is a partial cross-sectional schematic diagram of a micro-LED display panel of another embodiment of the present invention. Referring to FIG2 , the micro-LED display panel 100a of the present embodiment is similar to the micro-LED display panel 100 of FIG1C , and the main difference between the two is that, in the three pixel units U of FIG1C , the green micro-LED 140g is arranged in the center, and the two blue micro-LEDs 140b are arranged on both sides; however, in the present embodiment, as shown in FIG2 , the green micro-LED 140g is arranged on one side, and the two blue micro-LEDs 140b are arranged in the center and the other side, respectively.

FIG3 is a partial cross-sectional schematic diagram of a micro-LED display panel of another embodiment of the present invention. Referring to FIG3 , the micro-LED display panel 100b of the present embodiment is similar to the micro-LED display panel 100a of FIG2 , and the main differences between the two are as follows. In the micro-LED display panel 100b of the present embodiment, the green sub-pixel (such as the pixel unit U on the right side of FIG3 ) is formed by using a blue micro-LED 140b and a wavelength conversion material 160g filled in the pixel unit U, wherein the wavelength conversion material 160g is, for example, a green quantum dot material, which can convert the blue light emitted by the blue micro-LED 140b into green light. That is, the wavelength conversion material 160 used in this embodiment includes two types of wavelength conversion material 160r and wavelength conversion material 160g, wherein the wavelength conversion material 160r is a red quantum dot material, and the wavelength conversion material 160g is a green quantum dot material. In this way, the structure of FIG. 3 can also form a red sub-pixel, a green sub-pixel, and a blue sub-pixel, wherein the planarization layer 170 is located in the central pixel unit U, so the blue sub-pixel is located in the center, for example.

FIG4 is a partial cross-sectional schematic diagram of a micro-LED display panel of another embodiment of the present invention. Referring to FIG4 , the micro-LED display panel 100c of this embodiment is similar to the micro-LED display panel 100b of FIG3 , and the main differences between the two are as follows. In the micro-LED display panel 100c of this embodiment, the wavelength conversion material 160g using green quantum dots is located in the pixel unit U in the center of FIG4 , and the flattening layer 170 is located in the pixel unit U on one side of FIG4 .

In addition, in the present embodiment, the maximum height J of the gap G around the at least one pixel unit U relative to the substrate 110 is smaller than the height C1 of the micro-LED 140 in the at least one pixel unit U relative to the substrate 110, and in the at least one pixel unit U, the top surface 144 of the micro-LED 140 is exposed outside the filling structure 150. In addition, in the present embodiment, in the at least one pixel unit U, the upper surface 152 of the filling structure 150 is flush with the top surface 144 of the micro-LED 140.

FIG. 5A and FIG. 5B are partial cross-sectional schematic diagrams for illustrating the manufacturing process of a micro-LED display panel of another embodiment of the present invention. Referring to FIG. 5A and FIG. 5B , the micro-LED display panel 100d of the present embodiment is similar to the micro-LED display panel 100c of FIG. 1C , and the main differences between the two are as follows. In the present embodiment, a first height H1 of the filling structure 150 relative to the substrate 110 in one pixel unit U is different from a second height H2 of the filling structure 150 relative to the substrate 110 in another pixel unit U. Specifically, when the fluidity of the material of the filling structure 150 filled in the central pixel unit U is poor (or the viscosity coefficient is high), the material of the filling structure 150 in the central pixel unit U will encounter some resistance when flowing to the pixel units U on both sides through the gap G, causing the first height H1 of the filling structure 150 in the central pixel unit U relative to the substrate 110 to be higher than any one of the second height H2 and the third height H3 of the filling structure 150 in the pixel units U on both sides relative to the substrate 110.

In addition, in the present embodiment, the height of the filling structure 150 in the pixel unit U having the wavelength conversion material 160 (such as the pixel unit U on the left side of FIG. 5B ) relative to the substrate 110 (i.e., the second height H2) is smaller than the height of the filling structure 150 in the pixel unit U not having the wavelength conversion material 160 (such as the pixel unit U in the center of FIG. 5B ) relative to the substrate 110 (i.e., the first height H1). In this way, the wavelength conversion material 160 can have a thicker thickness, thereby achieving a better wavelength conversion effect.

6A and 6B are partial cross-sectional schematic diagrams for illustrating the manufacturing process of a micro-LED display panel of another embodiment of the present invention. Referring to FIG. 6A and FIG. 6B , the micro-LED display panel 100e of this embodiment is similar to the micro-LED display panel 100d of FIG. 5B , and the main differences between the two are as follows. In the step of FIG. 6A , the material of the filling structure 150 is filled in the pixel unit U on one side (e.g., the left side) of FIG. 6A . Since the material of the filling structure 150 has poor fluidity (or high viscosity coefficient) in this embodiment, it will encounter some resistance when it overflows through the two gaps G to the pixel unit U on the right side of FIG. 6A , so that the third height H3′ of the filling structure 150 relative to the substrate 110 in the pixel unit U on the right side is the lowest. On the other hand, the material of the filling structure 150 will also encounter some resistance when it overflows through the gap G to the pixel unit U in the center of FIG. 6A , so that the first height H1′ of the filling structure 150 relative to the substrate 110 in the center pixel unit U is centered, and the second height H2′ of the filling structure 150 relative to the substrate 110 in the pixel unit U on the left side is the highest. In short, the second height H2' is greater than the first height H1', and the first height H1' is greater than the third height H3'. In other words, the heights of the plurality of continuously distributed filling structures 150 decrease from left to right in a step-like manner. However, in other embodiments, the heights of the plurality of continuously distributed filling structures 150 may also increase from left to right in a step-like manner.

In the two embodiments of FIG. 5A to FIG. 6B , the height of the filling structure 150 in each pixel unit U is different, depending on which pixel unit U the material of the filling structure 150 is filled from, and the farther the pixel unit U is from the filling position, the lower the height of the filling structure 150 .

Fig. 7 is a partial cross-sectional schematic diagram of a micro-LED display panel according to another embodiment of the present invention. Referring to Fig. 7, the micro-LED display panel 100f of this embodiment is similar to the micro-LED display panel 100 of Fig. 1C, and the main differences between the two are as follows. In the micro-LED display panel 100f of the present embodiment, the maximum height of the gap around at least one pixel unit U relative to the substrate 110 (for example, the height J1 of the larger gap G1 relative to the substrate 110) is greater than the height C1 of the micro-LED in the at least one pixel unit U (such as the micro-LED 140 on the left) relative to the substrate 110, and the filling structure 150 in the at least one pixel unit U covers the top surface 144 of the micro-LED 140 in the at least one pixel unit U. In the present embodiment, the ratio of the height C1 of the micro-LED 140 in the at least one pixel unit U relative to the substrate 110 to the height (equal to the first height H1 in the present embodiment, for example) of the filling structure 150 in the at least one pixel unit U relative to the substrate 110 is greater than 0.8 and less than 1, for example, 0.85 or 0.9. On the other hand, the height J2 of the smaller gap G2 relative to the substrate 110 is smaller than the height J1.

In addition, in the present embodiment, the gap G between a portion of the second light shielding layer 130 and the first light shielding layer 120 is a plurality of gaps of different heights (such as gaps G1 and G2), and the height of the filling structure 150 extending to the adjacent pixel unit U relative to the substrate 110 (in the present embodiment, for example, equal to the first height H1) is greater than the height J1 of the maximum height of the gap G1 relative to the substrate 110.

FIG8 is a partial cross-sectional schematic diagram of a micro-LED display panel of another embodiment of the present invention. Referring to FIG8 , the micro-LED display panel 100g of the present embodiment is similar to the micro-LED display panel 100f of FIG7 , and the main differences between the two are as follows. Compared with the material of the filling structure 150 used in FIG7 , the material of the filling structure 150 of the present embodiment has poor fluidity (or a higher viscosity coefficient) during filling, so the first height H1 of the filling structure 150 relative to the substrate 110 in the middle pixel unit U is the highest, and the height of the filling structure 150 extending to other adjacent pixel units U relative to the substrate 110 (such as the second height H2 and the third height H3) is positively correlated with the size of the gap G between the filling structure 150 and the middle pixel unit U. For example, if the height J1 of the gap G1 relative to the substrate 110 is larger, then the height of the filling structure 150 in the adjacent pixel unit U next to the gap G1 relative to the substrate 110 (i.e., the second height H2) will be larger. In contrast, if the height J2 of the gap G2 relative to the substrate 110 is smaller, then the height of the filling structure 150 in the adjacent pixel unit U next to the gap G2 relative to the substrate 110 (i.e., the third height H3) will be smaller.

FIG9 is a partial cross-sectional schematic diagram of a micro-LED display panel of another embodiment of the present invention. Referring to FIG9 , the micro-LED display panel 100h of the present embodiment is similar to the micro-LED display panel 100d of FIG5B , and the height of the filling structure 150 in the pixel unit U provided with the wavelength conversion material 160 relative to the substrate 110 (such as the second height H2”) is smaller than the height of the filling structure 150 in the pixel unit U not provided with the wavelength conversion material relative to the substrate 110 (such as the first height H1” or the third height H3”). Furthermore, in the pixel unit U provided with the wavelength conversion material 160 (such as the red quantum dot material), the filling structure 150 is not The top surface 144 of the micro-LED 140 is covered by the filling structure 150, so that the wavelength conversion material 160 can be thicker, thereby further improving the wavelength conversion efficiency and color purity. In this embodiment, the height J1 of the gap G1 around the pixel unit U relative to the substrate 110 is less than the height C1 of the micro-LED 140 relative to the substrate 110, and the filling structure 150 in the pixel unit U will not cover the top surface 144 of the micro-LED 140. However, in other embodiments, when the height J1 is greater than the height C1, the filling structure 150 in the pixel unit U will cover the top surface 144 of the micro-LED 140.

In summary, in the micro-LED display panel of the embodiment of the present invention, since the filling structure is used to fill the gap to repair the defect of the gap, when the wavelength conversion material is subsequently injected into the pixel unit, the wavelength conversion material will not overflow to the adjacent pixel unit through the gap to cause the problem of color crosstalk. Therefore, the micro-LED display panel of the embodiment of the present invention can achieve color output with higher color purity.

100, 100a, 100b, 100c, 100d, 100e, 100f, 100g, 100h: micro-LED display panel 110: substrate 120: first light shielding layer 130: second light shielding layer 140: micro-LED 140b: blue light micro-LED 140g: green light micro-LED 142: surrounding surface 144: top surface 150: filling structure 152: upper surface 160, 160g, 160r: wavelength conversion material 170: flat layer C1, J1, J2: height G, G1, G2: gap H1, H1', H1": first height H2, H2’, H2”: Second height H3, H3’, H3”: Third height J: Maximum height U: Pixel unit

Figures 1A to 1C are partial cross-sectional schematic diagrams for illustrating the manufacturing process of a micro-LED display panel of an embodiment of the present invention. Figure 2 is a partial cross-sectional schematic diagram of a micro-LED display panel of another embodiment of the present invention. Figure 3 is a partial cross-sectional schematic diagram of a micro-LED display panel of another embodiment of the present invention. Figure 4 is a partial cross-sectional schematic diagram of a micro-LED display panel of another embodiment of the present invention. Figures 5A and 5B are partial cross-sectional schematic diagrams for illustrating the manufacturing process of a micro-LED display panel of another embodiment of the present invention. Figures 6A and 6B are partial cross-sectional schematic diagrams for illustrating the manufacturing process of a micro-LED display panel of another embodiment of the present invention. FIG. 7 is a partial cross-sectional schematic diagram of a micro-LED display panel of another embodiment of the present invention. FIG. 8 is a partial cross-sectional schematic diagram of a micro-LED display panel of another embodiment of the present invention. FIG. 9 is a partial cross-sectional schematic diagram of a micro-LED display panel of another embodiment of the present invention.

100: Micro-LED display panel

110:Substrate

120: First light shielding layer

130: Second light shielding layer

140: Micro LED

140b: Blue light micro diode

140g: Green light micro diode

142:Surrounding surface

144: Top

150: Filling structure

160: Wavelength conversion material

170: Leveling layer

G: Gap

U: Pixel unit

Claims (11)

A micro-LED display panel comprises: a substrate; a first light shielding layer disposed on the substrate; a second light shielding layer disposed on the first light shielding layer, wherein the second light shielding layer defines a plurality of pixel units arranged in an array; and a plurality of micro-LEDs disposed on the first light shielding layer, wherein each pixel unit is provided with at least one of the micro-LEDs, wherein a gap is provided between a portion of the second light shielding layer and the first light shielding layer, and the gap has a filling structure, and the material of the filling structure is different from the material of the second light shielding layer. A micro-luminescent diode display panel as described in claim 1, wherein the filling structure extends to at least one pixel unit adjacent to the gap, and is arranged on a peripheral surface of the micro-luminescent diode in the at least one pixel unit adjacent to the gap. The micro-luminescent diode display panel as described in claim 2, wherein the filling structure is further configured on a top surface of the micro-luminescent diode in at least one pixel unit adjacent to the gap. A micro-LED display panel as described in claim 2, wherein a first height of the filling structure relative to the substrate in one pixel unit is different from a second height of the filling structure relative to the substrate in another pixel unit. A micro-LED display panel as described in claim 1, wherein a wavelength conversion material is provided in at least one pixel unit. In the micro-LED display panel as described in claim 5, a height of the filling structure in the pixel unit provided with the wavelength conversion material relative to the substrate is smaller than a height of the filling structure in the pixel unit not provided with the wavelength conversion material relative to the substrate. The micro-LED display panel as described in claim 1, wherein the gap between part of the second light-shielding layer and the first light-shielding layer is a plurality of gaps of different heights, and the height of the filling structure extending to the adjacent pixel unit relative to the substrate is greater than the height of the maximum gap relative to the substrate. A micro-LED display panel as described in claim 1, wherein the maximum height of the gap around the at least one pixel unit relative to the substrate is greater than the height of the micro-LED in the at least one pixel unit relative to the substrate, and the filling structure in the at least one pixel unit covers a top surface of the micro-LED in the at least one pixel unit. A micro-LED display panel as described in claim 8, wherein a ratio of a height of the micro-LED in at least one pixel unit relative to the substrate to a height of the filling structure in at least one pixel unit relative to the substrate is greater than 0.8 and less than 1. A micro-LED display panel as described in claim 1, wherein the maximum height of the gap around the at least one pixel unit relative to the substrate is smaller than the height of the micro-LED in the at least one pixel unit relative to the substrate, and in the at least one pixel unit, a top surface of the micro-LED is exposed outside the filling structure. A micro-luminescent diode display panel as described in claim 10, wherein in the at least one pixel unit, the two upper surfaces of the filling structure are flush with a top surface of the micro-luminescent diode.

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