Display panel

Abstract

A display panel comprises a substrate, a light-emitting element, a reflecting layer and a micro lens. The light-emitting element is arranged on the substrate and is provided with a forward light-emitting surface back to the substrate and a lateral light-emitting surface connected with the forward light-emitting surface; the reflecting layer is arranged on the substrate and covers the lateral light-emitting surface of the light-emitting element; the reflective layer has a flat surface facing away from the substrate. The forward light-emitting surface of the light-emitting element has a first height relative to the substrate surface of the substrate; the flat surface of the reflecting layer has a second height relative to the surface of the substrate; the first height is greater than the second height; the micro lens is arranged on the light-emitting element and covers the forward light-emitting surface.

Description

Technical Field

[0001] The present invention relates to a display panel, and more particularly to a display panel provided with light-emitting elements and microlenses. Background Art

[0002] In a self-emitting display panel, in addition to forward light emission, the light-emitting element may also emit light laterally. In order to increase the frontal brightness of the display panel, in addition to improving the light extraction efficiency of the light-emitting element itself, a concept of guiding the lateral light emitted by the light-emitting element to the forward light-emitting surface for emission and adding microlenses on the forward light-emitting surface has been proposed. For example, a reflective layer can be covered on the lateral light-emitting surface of the light-emitting element to reflect the lateral light and increase the probability of its emission from the forward light-emitting surface. However, the process margin of the reflective layer is easily reduced due to the position offset of the light-emitting element bonded to the substrate.

[0003] For example, if the thickness of the reflective layer is too small, it can only cover a part of the lateral light-emitting surface to meet the alignment requirements of subsequent film layers (such as a light-shielding layer used to improve color purity and contrast), but part of the forward light extraction efficiency will be sacrificed. On the contrary, if the thickness of the reflective layer is too large, it can completely cover the lateral light-emitting surface of the light-emitting element. Although the reuse rate of the lateral light can be maximized, the optical performance of the subsequent film layers is also likely to deteriorate due to the position offset of the light-emitting element. Therefore, how to balance the alignment requirements of subsequent film layers and the process margin when the light-emitting element has a position offset is still an urgent problem to be solved. Summary of the Invention

[0004] The present invention provides a display panel with better alignment accuracy between the microlens and the light-emitting element.

[0005] The display panel of the present invention includes a substrate, a light-emitting element, a reflective layer, and a microlens; the light-emitting element is disposed on the substrate and has a forward light-emitting surface facing away from the substrate and a lateral light-emitting surface connected to the forward light-emitting surface; the reflective layer is disposed on the substrate and covers the lateral light-emitting surface of the light-emitting element. The reflective layer has a flat surface facing away from the substrate; the forward light-emitting surface of the light-emitting element has a first height relative to the substrate surface of the substrate; the flat surface of the reflective layer has a second height relative to the substrate surface; the first height is greater than the second height; the microlens is disposed on the light-emitting element and covers the forward light-emitting surface.

[0006] In an embodiment of the display panel of the present invention, the reflective layer further has a protruding portion protruding from the flat surface, the protruding portion covers the lateral light-emitting surface, and the microlens covers the protruding portion of the reflective layer.

[0007] In an embodiment of the foregoing display panel of the present invention, the microlens has a lens width along a direction parallel to the surface of the substrate, and a lens height along the normal direction of the surface of the substrate, and the ratio of the lens height to the lens width is greater than or equal to 0.2 and less than or equal to 1.0.

[0008] In an embodiment of the foregoing display panel of the present invention, the light-emitting element has an element width along the direction, and the ratio of the lens width to the element width is greater than or equal to 1.0 and less than or equal to 1.5.

[0009] In an embodiment of the foregoing display panel of the present invention, it further includes:

[0010] A side-wing microlens, disposed on the reflective layer, wherein the microlens has a side wall surface surrounding the forward light-emitting surface, and the side-wing microlens covers the side wall surface of the microlens.

[0011] In an embodiment of the foregoing display panel of the present invention, the side-wing microlens covers the reflective layer and does not overlap the forward light-emitting surface of the light-emitting element along the normal direction of the surface of the substrate.

[0012] In an embodiment of the foregoing display panel of the present invention, there is a first included angle between the side wall surface of the microlens and the flat surface, and a second included angle between the side-wing microlens connecting a side-wing surface of the reflective layer and the flat surface, and the second included angle is less than the first included angle.

[0013] In an embodiment of the foregoing display panel of the present invention, it further includes:

[0014] A light-shielding layer, disposed on the reflective layer and covering the reflective layer and a side-wing surface of the side-wing microlens connecting the reflective layer.

[0015] In an embodiment of the foregoing display panel of the present invention, it further includes:

[0016] A flat layer, disposed on the reflective layer, wherein the microlens has a side wall surface surrounding the forward light-emitting surface, and the flat layer covers the side wall surface of the microlens.

[0017] In an embodiment of the foregoing display panel of the present invention, it further includes:

[0018] A side-wing microlens, disposed on the flat layer and covering the side wall surface of the microlens.

[0019] In an embodiment of the foregoing display panel of the present invention, it further includes:

[0020] A light-shielding layer, disposed on the flat layer and covering the flat layer and a side-wing surface of the side-wing microlens connecting the reflective layer.

[0021] Based on the above, in the display panel according to an embodiment of the present invention, since the reflective layer has a self-alignment characteristic with respect to the light-emitting element during the manufacturing process, the flat surface of the reflective layer will be closer to the substrate surface than the forward light-emitting surface of the light-emitting element. Accordingly, the offset error during the bonding of the light-emitting element to the substrate can be effectively avoided from affecting the manufacturing space of the reflective layer. In addition, by covering the forward light-emitting surface of the light-emitting element with a microlens, in addition to effectively increasing the alignment accuracy of the microlens with respect to the light-emitting element, the influence of the offset error during the bonding of the light-emitting element to the substrate on the subsequent film layer structure manufacturing process can also be significantly reduced. Description of the Drawings

[0022] Figure 1 is a cross-sectional schematic view of a display panel according to a first embodiment of the present invention.

[0023] Figures 2A to 2C is Figure 1 a cross-sectional schematic view of the manufacturing process of the display panel.

[0024] Figure 3 is a cross-sectional schematic view of a display panel according to a second embodiment of the present invention.

[0025] Figures 4A to 4D is Figure 3 a cross-sectional schematic view of the manufacturing process of the display panel.

[0026] Figure 5 is a cross-sectional schematic view of a display panel according to a third embodiment of the present invention.

[0027] Figures 6A to 6E is Figure 5 a cross-sectional schematic view of the manufacturing process of the display panel.

[0028] Among them, reference numerals:

[0029] 10, 20, 30: Display panel

[0030] 100: Substrate

[0031] 100s: Substrate surface

[0032] 105: Bonding pad

[0033] 120: Light-emitting element

[0034] 120es1: Forward light-emitting surface

[0035] 120es2: Lateral light-emitting surface

[0036] 121: First electrode

[0037] 122: Second electrode

[0038] 125: Epitaxial structure layer

[0039] 140: Reflective layer

[0040] 140fs: Flat surface

[0041] 140M: Reflective material layer

[0042] 140p: Protrusion

[0043] 150: Flat layer

[0044] 150M: Flat material layer

[0045] 160, 160A: Microlens

[0046] 160M: Microlens material layer

[0047] 160sw: Sidewall surface

[0048] 165, 165A: Flank microlens

[0049] 165M: Flank microlens material layer

[0050] 165s: Flank surface

[0051] 180: Light-shielding layer

[0052] 180M: Light-shielding material layer

[0053] 190: Encapsulation layer

[0054] A1, A2: Included angle

[0055] H1, H2: Height

[0056] H L : Lens height

[0057] M1, M2, M2a, M2b, M3: Photomask

[0058] OP1, OP2, OP2a, OP2b, OP3: Opening

[0059] W D : Element width

[0060] W L : Lens width

[0061] X, Z: Direction Detailed implementation manners

[0062] As used herein, "about", "approximate", "substantially", or "essentially" includes the stated value and an average within an acceptable deviation range of a particular value as determined by a person of ordinary skill in the art, taking into account the particular amounts of the measurements being discussed and the errors associated with the measurements (i.e., the limitations of the measurement system). For example, "about" can mean within one or more standard deviations of the stated value, or for example within ±30%, ±20%, ±15%, ±10%, ±5%. Further, "about", "approximate", "substantially", or "essentially" as used herein can be selected with respect to the nature of the measurement, the nature of the cut, or other properties, to provide a more acceptable deviation range or standard deviation, rather than applying a single standard deviation to all properties.

[0063] In the drawings, for clarity, the thicknesses of layers, films, panels, regions, etc. are exaggerated. It should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element, or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, no intervening elements are present. As used herein, "connected" can refer to physical and / or electrical connection. Further, "electrically connected" can mean that other elements are present between two elements.

[0064] In addition, relative terms such as "lower" or "bottom" and "upper" or "top" may be used herein to describe the relationship of one element to another element, as shown in the figures. It should be understood that the relative terms are intended to include different orientations of the device in addition to the orientations shown in the figures. For example, if the device in one figure is flipped, an element described as being on the "lower" side of another element will be oriented on the "upper" side of the other element. Thus, the exemplary term "lower" can include both the "lower" and "upper" orientations, depending on the particular orientation of the figure. Similarly, if the device in one figure is flipped, an element described as being "beneath" or "below" another element will be oriented as being "above" the other element. Thus, the exemplary terms "above" or "below" can include both the above and below orientations.

[0065] Exemplary embodiments are described herein with reference to cross-sectional views that are schematic illustrations of idealized embodiments. Accordingly, variations in the illustrated shapes as a result of, for example, manufacturing techniques and / or tolerances are to be expected. Thus, the embodiments described herein should not be construed as limited to the particular shapes of regions shown herein, but rather include, for example, shape variations resulting from manufacturing. For example, regions shown or described as flat will typically have rough and / or non-linear features. In addition, the sharp angles shown may be rounded. Thus, the regions shown in the figures are essentially schematic in nature, and their shapes are not intended to illustrate the exact shape of a region and are not intended to limit the scope of the patent application.

[0066] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals are used in the drawings and the description to refer to the same or like parts.

[0067] Figure 1 is a cross-sectional schematic view of a display panel according to a first embodiment of the present invention. Figures 2A to 2C is Figure 1 a cross-sectional schematic view of the manufacturing process of the display panel of. Please refer to Figure 1 , the display panel 10 includes a substrate 100 and a light-emitting element 120. The light-emitting element 120 is disposed on the substrate 100. In this embodiment, the substrate 100 is, for example, a circuit board provided with a pixel circuit layer (not shown) and a plurality of bonding pads 105, and the light-emitting element 120 is adapted to be bonded to the bonding pads 105 to electrically connect to the substrate 100. Although Figure 1 only one light-emitting element 120 is shown, it is understood that the display panel 10 may include a plurality of light-emitting elements 120, and these light-emitting elements 120 may be arranged in an array on the substrate 100.

[0068] For example, the light-emitting element 120 may be a micro light emitting diode (micro-LED), and includes a first electrode 121, a second electrode 122, and an epitaxial structure layer 125. The epitaxial structure layer 125 may include a first-type semiconductor layer (not shown), a second-type semiconductor layer (not shown), and a light-emitting layer (not shown), wherein the light-emitting layer is disposed between the first-type semiconductor layer and the second-type semiconductor layer. The first electrode 121 and the second electrode 122 are electrically connected to the first-type semiconductor layer and the second-type semiconductor layer, respectively. The first electrode 121 and the second electrode 122 of the light-emitting element 120 may be respectively bonded to two bonding pads 105 to realize the electrical connection relationship between the light-emitting element 120 and the substrate 100.

[0069] In this embodiment, the first electrode 121 and the second electrode 122 of the light-emitting element 120 may be disposed on the same side of the epitaxial structure layer 125 facing the substrate 100. More specifically, the light-emitting element 120 may be a flip-chip type micro-LED. In this embodiment, the light-emitting element 120 has a forward light-emitting surface 120es1 facing away from the substrate 100 and a lateral light-emitting surface 120es2 connecting the forward light-emitting surface 120es1. The lateral light-emitting surface 120es2 may surround the forward light-emitting surface 120es1.

[0070] To increase the light-emitting intensity of the light-emitting element 120 on the forward light-emitting surface 120es1, the display panel 10 further includes a reflective layer 140 on the substrate 100, and the reflective layer 140 covers the lateral light-emitting surface 120es2 of the light-emitting element 120. The reflective layer 140 is adapted to reflect the light emitted by the light-emitting layer (not shown) of the light-emitting element 120 toward the lateral light-emitting surface 120es2 back to the epitaxial structure layer 125, so as to increase the chance of the light being emitted from the forward light-emitting surface 120es1.

[0071] Specifically, the reflective layer 140 has a flat surface 140fs facing away from the substrate 100 and a protruding portion 140p protruding from the flat surface 140fs. It should be particularly noted that the forward light-emitting surface 120es1 of the light-emitting element 120 has a height H1 relative to the substrate surface 100s of the substrate 100, the flat surface 140fs has a height H2 relative to the substrate surface 100s, and the height H1 is greater than the height H2. That is to say, the light-emitting element 120 protrudes from the flat surface 140fs of the reflective layer 140.

[0072] On the other hand, the protruding portion 140p of the reflective layer 140 is disposed around the lateral light-emitting surface 120es2 of the light-emitting element 120 and covers a part of the lateral light-emitting surface 120es2 of the light-emitting element 120. More specifically, the protruding portion 140p covers the portion of the lateral light-emitting surface 120es2 that is higher than the flat surface 140fs. For example, in this embodiment, the covering relationship of the protruding portion 140p of the reflective layer 140 to a part of the lateral light-emitting surface 120es2 of the light-emitting element 120 is achieved by directly contacting the lateral light-emitting surface 120es2. That is, the protruding portion 140p can directly cover a part of the lateral light-emitting surface 120es2 of the light-emitting element 120. However, the present invention is not limited thereto. In other embodiments, other film layers may also be provided between the protruding portion 140p and the lateral light-emitting surface 120es2 of the light-emitting element 120.

[0073] To adjust the light-emitting pattern of the light-emitting element 120, the display panel 10 further includes a microlens 160 disposed on the light-emitting element 120. It should be particularly noted that the microlens 160 covers the forward light-emitting surface 120es1 of the light-emitting element 120 and the protruding portion 140p of the reflective layer 140. For example, in this embodiment, the microlens 160 directly contacts the forward light-emitting surface 120es1 of the light-emitting element 120 and the protruding portion 140p of the reflective layer 140. That is, the microlens 160 can directly cover the forward light-emitting surface 120es1 and the protruding portion 140p. However, the present invention is not limited thereto. In other embodiments, other film layers may also be provided between the microlens 160 and the light-emitting element 120 (and / or the protruding portion 140p), and the setting of the other film layers will not affect the covering relationship of the microlens 160 to the light-emitting element 120.

[0074] To increase the display contrast, a light-shielding layer 180 may be further disposed on the reflective layer 140 of the display panel 10. The light-shielding layer 180 covers the flat surface 140fs of the reflective layer 140 and the side wall surface 160sw of the microlens 160 around the forward light-emitting surface 120es1, and is used to absorb the light emitted in an unexpected direction and the ambient light. The display panel 10 may further include a packaging layer 190 covering the microlens 160 and the light-shielding layer 180. For example, in this embodiment, the light-shielding layer 180 is in direct contact with the flat surface 140fs of the reflective layer 140 and the side wall surface 160sw of the microlens 160 around the forward light-emitting surface 120es1. That is, the light-shielding layer 180 can directly cover the flat surface 140fs of the reflective layer 140 and the side wall surface 160sw of the microlens 160 around the forward light-emitting surface 120es1. However, the present invention is not limited thereto. In other embodiments, other film layers may be provided between the light-shielding layer 180 and the side wall surface 160sw of the reflective layer 140 and / or the microlens 160.

[0075] The manufacturing process of the display panel 10 will be exemplarily described below.

[0076] Please refer to Figure 2A , after the light-emitting element 120 is bonded to the bonding pad 105 of the substrate 100, a reflective material layer 140M covering the light-emitting element 120 is formed on the substrate surface 100s. The material of the reflective material layer 140M includes, for example, white or highly reflective materials. Then, an exposure and development process is performed on the reflective material layer 140M using a photomask M1. Among them, the photomask M1 has an opening OP1 overlapping the light-emitting element 120, and in any direction parallel to the substrate surface 100s, the width of the opening OP1 is greater than the width of the light-emitting element 120.

[0077] In this embodiment, the reflective material layer 140M is, for example, a negative photoresist, but not limited thereto. After the exposure and development process, the reflective material layer 140M forms a reflective layer 140, as Figure 2B shown. It should be specifically noted that the exposure process of the reflective material layer 140M is, for example, a weak exposure method. Therefore, after the development process, the portion of the reflective material layer 140M above the forward light-emitting surface 120es1 of the light-emitting element 120 will be removed, and only the portion covering the side light-emitting surface 120es2 remains. Thereby, self-alignment of the reflective layer 140 with respect to the light-emitting element 120 can be achieved. Even if the light-emitting element 120 has an unexpected position shift during the bonding process with the substrate 100, it will not affect the alignment accuracy of the reflective layer 140.

[0078] Next, a microlens material layer 160M is formed on the reflective layer 140, and the microlens material layer 160M is subjected to an exposure and development process using a photomask M2. The photomask M2 has an opening OP2 overlapping the light-emitting element 120, and in any direction parallel to the substrate surface 100s, the width of the opening OP2 can be greater than or equal to the width of the light-emitting element 120. In this embodiment, the microlens material layer 160M is made of, for example, an organic negative photoresist material, but is not limited thereto. After the exposure and development process, the microlens material layer 160M forms a microlens 160, as Figure 2B and Figure 2C shown. In this embodiment, the width of the opening OP2 of the photomask M2 is, for example, greater than the width of the light-emitting element 120. Therefore, the formed microlens 160 also covers the protrusion 140p of the reflective layer 140.

[0079] The exposure process of the microlens material layer 160M is, for example, a strong exposure method. Therefore, after the development process, the portion of the microlens material layer 160M above the forward light-emitting surface 120es1 of the light-emitting element 120 is retained, and the unexposed or under-exposed portions are removed. It should be particularly noted that the contour of the microlens 160 can be adjusted by the amount of exposure. Since the microlens 160 covers the forward light-emitting surface 120es1 of the light-emitting element 120, its alignment accuracy relative to the light-emitting element 120 can be greatly improved, thereby reducing the influence of the offset error of the light-emitting element 120 during bonding to the substrate 100 on the subsequent film layer structure process.

[0080] Please refer to Figure 2C , next, a light-shielding material layer 180M is formed on the reflective layer 140, and the light-shielding material layer 180M is subjected to an exposure and development process using a photomask M3. The photomask M3 has an opening OP3 overlapping the light-emitting element 120, and in any direction parallel to the substrate surface 100s, the width of the opening OP3 is greater than the width of the microlens 160. In this embodiment, the light-shielding material layer 180M is, for example, a negative photoresist, but is not limited thereto. After the exposure and development process, the light-shielding material layer 180M forms a light-shielding layer 180 as Figure 1 shown.

[0081] It should be particularly noted that the exposure process of the light-shielding material layer 180M is, for example, a weak exposure method. Therefore, after the development process, the portion of the light-shielding material layer 180M above the microlens 160 and overlapping the forward light-emitting surface 120es1 is removed, leaving only the portion covering the sidewall surface 160sw of the microlens 160. Thereby, self-alignment of the light-shielding layer 180 relative to the microlens 160 can be achieved. Even if the light-emitting element 120 has an unexpected position shift during the bonding process with the substrate 100, it will not affect the alignment accuracy of the light-shielding layer 180.

[0082] Finally, an encapsulation layer 190 is formed to cover the microlens 160 and the light-shielding layer 180. The material of the encapsulation layer 190 includes, for example, photoresist, resin, silica gel, or other suitable materials. Thus, the fabrication of the display panel 10 is completed. The display panel 10 includes a substrate 100, a light-emitting element 120, a reflective layer 140, and a microlens 160. The reflective layer 140 is disposed on the substrate 100 and covers the lateral light-emitting surface 120es2 of the light-emitting element 120. Since the reflective layer 140 has a self-alignment characteristic with respect to the light-emitting element 120 during the manufacturing process, the flat surface 140fs of the reflective layer 140 will be closer to the substrate surface 100s than the forward light-emitting surface 120es1 of the light-emitting element 120. Accordingly, the offset error of the light-emitting element 120 during bonding to the substrate 100 can be effectively prevented from affecting the manufacturing space of the reflective layer 140. On the other hand, the microlens 160 is disposed on the light-emitting element 120 and covers the forward light-emitting surface 120es1. Accordingly, in addition to effectively increasing the alignment accuracy of the microlens 160 with respect to the light-emitting element 120, the influence of the offset error of the light-emitting element 120 during bonding to the substrate 100 on the subsequent film layer structure (such as the light-shielding layer 180) manufacturing process can be significantly reduced. Figure 1 Shown in the figure is the fabrication of the display panel 10. The display panel 10 includes a substrate 100, a light-emitting element 120, a reflective layer 140, and a microlens 160. The reflective layer 140 is disposed on the substrate 100 and covers the lateral light-emitting surface 120es2 of the light-emitting element 120. Since the reflective layer 140 has a self-alignment characteristic with respect to the light-emitting element 120 during the manufacturing process, the flat surface 140fs of the reflective layer 140 will be closer to the substrate surface 100s than the forward light-emitting surface 120es1 of the light-emitting element 120. Accordingly, the offset error of the light-emitting element 120 during bonding to the substrate 100 can be effectively prevented from affecting the manufacturing space of the reflective layer 140. On the other hand, the microlens 160 is disposed on the light-emitting element 120 and covers the forward light-emitting surface 120es1. Accordingly, in addition to effectively increasing the alignment accuracy of the microlens 160 with respect to the light-emitting element 120, the influence of the offset error of the light-emitting element 120 during bonding to the substrate 100 on the subsequent film layer structure (such as the light-shielding layer 180) manufacturing process can be significantly reduced.

[0083] Some other embodiments will be listed below to illustrate the present invention in detail. The same components will be denoted by the same reference symbols, and the description of the same technical content will be omitted. For the omitted part, please refer to the foregoing embodiments and will not be repeated hereinafter.

[0084] Figure 3 is a cross-sectional schematic view of a display panel according to a second embodiment of the present invention. Figures 4A to 4D is Figure 3 a cross-sectional schematic view of the manufacturing process of the display panel. Please refer to Figure 3 , the difference between the display panel 20 of this embodiment and Figure 1 the display panel 10 is that the configuration of the microlens is different. Specifically, in this embodiment, the display panel 20 may further include a flank microlens 165 disposed on the reflective layer 140 and covering the sidewall surface 160sw of the microlens 160A. For example, in this embodiment, the flank microlens 165 directly contacts the sidewall surface 160sw of the microlens 160A. That is, the flank microlens 165 can directly cover the sidewall surface 160sw of the microlens 160A. However, the present invention is not limited thereto. In other embodiments, other film layers may be provided between the flank microlens 165 and the sidewall surface 160sw of the microlens 160A.

[0085] Specifically, the microlens 160A and the light-emitting element 120 respectively have a lens width W L and an element width W Dand has a lens height H along the normal direction (e.g., direction Z) of the substrate surface 100s L . In this embodiment, the microlens 160A may have a relatively large aspect ratio. Preferably, the lens height H L to the lens width W L has a ratio greater than or equal to 0.2 and less than or equal to 1.0, and the lens width W L to the element width W D has a ratio greater than or equal to 1.0 and less than or equal to 1.5.

[0086] Compared with Figure 1 the microlens 160, since the microlens 160A of this embodiment has a higher lens height, the focal length of the microlens 160A can be closer to the forward light-emitting surface 120es1 of the light-emitting element 120, so as to further improve the optical effect of the microlens 160A, such as the forward light-emitting efficiency, but not limited thereto.

[0087] It should be particularly noted that, in this embodiment, the side wing microlens 165 does not overlap the forward light-emitting surface 120es1 of the light-emitting element 120 along the normal direction (e.g., direction Z) of the substrate surface 100s. By providing the side wing microlens 165, the adjustment flexibility of the light-emitting pattern of the light-emitting element 120 can be further increased.

[0088] In this embodiment, since the side wall surface 160sw of the microlens 160A is covered with the side wing microlens 165, the light-shielding layer 180 provided on the reflective layer 140 covers the side wing surface 165s of the side wing microlens 165. Preferably, there is an angle A1 between the side wall surface 160sw of the microlens 160A and the flat surface 140fs, and there is an angle A2 between the side wing surface 165s of the side wing microlens 165 and the flat surface 140fs, and the angle A2 is less than the angle A1. For example, in this embodiment, the light-shielding layer 180 is in direct contact with the side wing surface 165s of the side wing microlens 165. That is, the light-shielding layer 180 can directly cover the side wing surface 165s of the side wing microlens 165. However, the present invention is not limited thereto. In other embodiments, other film layers may be provided between the light-shielding layer 180 and the side wing surface 165s of the side wing microlens 165.

[0089] Hereinafter, the manufacturing process of the display panel 20 will be exemplarily described.

[0090] Please refer to Figure 4A, after the light-emitting element 120 is bonded to the bonding pad 105 of the substrate 100, a reflective material layer 140M covering the light-emitting element 120 is formed on the substrate surface 100s. The material of the reflective material layer 140M includes, for example, white or highly reflective materials. Then, an exposure and development process is performed on the reflective material layer 140M using a photomask M1. Among them, the photomask M1 has an opening OP1 overlapping the light-emitting element 120, and in any direction parallel to the substrate surface 100s, the width of the opening OP1 is greater than the width of the light-emitting element 120.

[0091] In this embodiment, the reflective material layer 140M is, for example, a negative photoresist, but not limited thereto. After the exposure and development process, the reflective material layer 140M forms a reflective layer 140, as Figure 4B shown. It should be specifically noted that the exposure process of the reflective material layer 140M is, for example, a weak exposure method. Therefore, after the development process, the portion of the reflective material layer 140M above the forward light-emitting surface 120es1 of the light-emitting element 120 will be removed, leaving only the portion covering the side light-emitting surface 120es2. Thereby, self-alignment of the reflective layer 140 with respect to the light-emitting element 120 can be achieved. Even if the light-emitting element 120 has an unexpected position shift during the bonding process with the substrate 100, it will not affect the alignment accuracy of the reflective layer 140.

[0092] Next, a microlens material layer 160M is formed on the reflective layer 140, and an exposure and development process is performed on the microlens material layer 160M using a photomask M2a. Among them, the photomask M2a has an opening OP2a overlapping the light-emitting element 120, and in any direction parallel to the substrate surface 100s, the width of the opening OP2a can be greater than or equal to the width of the light-emitting element 120. In this embodiment, the microlens material layer 160M is made of, for example, an organic negative photoresist material, but not limited thereto. After the exposure and development process, the microlens material layer 160M forms a microlens 160A, as Figure 4C shown. In this embodiment, the width of the opening OP2a of the photomask M2a is, for example, greater than the width of the light-emitting element 120. Therefore, the formed microlens 160A also covers the protrusion 140p of the reflective layer 140.

[0093] The exposure process of the microlens material layer 160M is, for example, carried out in a strong exposure manner. Therefore, after the development process, the part of the microlens material layer 160M above the forward light-emitting surface 120es1 of the light-emitting element 120 will be retained, while the unexposed or under-exposed parts will be removed. It should be particularly mentioned that the profile of the microlens 160A can be adjusted by the amount of exposure. Since the microlens 160A covers the forward light-emitting surface 120es1 of the light-emitting element 120, its alignment accuracy relative to the light-emitting element 120 can be greatly improved, thereby reducing the influence of the offset error of the light-emitting element 120 during bonding to the substrate 100 on the subsequent film layer structure process.

[0094] Please refer to Figure 4C , then, a flank microlens material layer 165M is formed on the reflective layer 140, and the flank microlens material layer 165M is subjected to an exposure and development process using a photomask M2b. Among them, the photomask M2b has an opening OP2b overlapping the light-emitting element 120 and the microlens 160A, and in any direction parallel to the substrate surface 100s, the width of the opening OP2b is greater than Figure 4B the width of the opening OP2a of the photomask M2a in Figure 4D . As shown in

[0095] The exposure process of the flank microlens material layer 165M is, for example, carried out in a strong exposure manner. Therefore, after the development process, the unexposed or under-exposed parts in the microlens material layer 160M will be removed. It should be particularly mentioned that the profile of the flank microlens 165 can be adjusted by the amount of exposure. Preferably, the flank microlens 165 and the microlens 160A can have the same refractive index, and the materials selected can be the same or different selectively.

[0096] Please refer to Figure 4D , then, a light-shielding material layer 180M is formed on the reflective layer 140, and the light-shielding material layer 180M is subjected to an exposure and development process using a photomask M3. Among them, the photomask M3 has an opening OP3 overlapping the light-emitting element 120, and in any direction parallel to the substrate surface 100s, the width of the opening OP3 is greater than the widths of the microlens 160A and the flank microlens 165. In this embodiment, the light-shielding material layer 180M is, for example, a negative photoresist, but not limited thereto. After the exposure and development process, the light-shielding material layer 180M forms a light-shielding layer 180 as shown in Figure 3 .

[0097] Specifically, the exposure process of the light-shielding material layer 180M is, for example, a weak exposure method. Therefore, after the development process, the portions of the light-shielding material layer 180M above the microlens 160A and the flank microlenses 165 are removed, leaving only the portion covering the flank surface 165s of the flank microlenses 165. Thereby, self-alignment of the light-shielding layer 180 with respect to the microlens 160A and the flank microlenses 165 can be achieved. Even if the light-emitting element 120 has an unexpected positional shift during the bonding process with the substrate 100, it will not affect the alignment accuracy of the light-shielding layer 180.

[0098] Finally, an encapsulation layer 190 is formed to cover the microlens 160A, the flank microlenses 165, and the light-shielding layer 180. The material of the encapsulation layer 190 includes, for example, photoresist, resin, silica gel, or other suitable materials. Thus, the fabrication of the Figure 3 display panel 20 is completed. In this embodiment, by increasing the lens height H L of the microlens 160A, the forward light extraction efficiency of the display panel 20 can be effectively improved. In addition, the configuration of the flank microlenses 165 can increase the adjustment flexibility of the light extraction light pattern.

[0099] Figure 5 is a cross-sectional schematic view of a display panel according to the third embodiment of the present invention. Figures 6A to 6E is Figure 5 a cross-sectional schematic view of the manufacturing process of the Figure 5 display panel. Referring to Figure 3 this, the main difference between the display panel 30 of this embodiment and the

[0100] display panel 20 is: the configuration of the flank microlenses is different. Specifically, in this embodiment, the display panel 30 may further include a flat layer 150 disposed on the reflective layer 140 and covering a portion of the side wall surface 160sw of the microlens 160A close to the reflective layer 140. For example, in this embodiment, the flat layer 150 directly contacts a portion of the side wall surface 160sw of the microlens 160A. That is, the flat layer 150 can directly cover a portion of the side wall surface 160sw of the microlens 160A. However, the present invention is not limited thereto. In other embodiments, other film layers may be provided between the flat layer 150 and a portion of the side wall surface 160sw of the microlens 160A.

[0100] In this embodiment, the flank microlenses 165A may be disposed on the flat layer 150. Therefore, different from Figure 3 the flank microlenses 165 which cover a portion of the side wall surface 160sw of the microlens 160A close to the reflective layer 140, the flank microlenses 165A of this embodiment cover a portion of the side wall surface 160sw of the microlens 160A far from the reflective layer 140. That is to say, the setting height of the flank microlenses 165A of this embodiment with respect to the microlens 160A is Figure 3is higher than that of the side micro-lens 165, so as to further improve the forward light extraction efficiency of the display panel 30.

[0101] The manufacturing process of the display panel 30 will be exemplarily described below.

[0102] Please refer to Figure 6A , after the light-emitting element 120 is bonded to the bonding pad 105 of the substrate 100, a reflective material layer 140M covering the light-emitting element 120 is formed on the substrate surface 100s. The material of the reflective material layer 140M includes, for example, white or highly reflective materials. Then, an exposure and development process is performed on the reflective material layer 140M using a photomask M1. Among them, the photomask M1 has an opening OP1 overlapping the light-emitting element 120, and in any direction parallel to the substrate surface 100s, the width of the opening OP1 is greater than the width of the light-emitting element 120.

[0103] In this embodiment, the reflective material layer 140M is, for example, a negative photoresist, but not limited thereto. After the exposure and development process, the reflective material layer 140M forms a reflective layer 140, as Figure 6B shown. It should be specifically noted that the exposure process of the reflective material layer 140M is, for example, a weak exposure method. Therefore, after the development process, the portion of the reflective material layer 140M above the forward light extraction surface 120es1 of the light-emitting element 120 will be removed, and only the portion covering the side light extraction surface 120es2 remains. Thereby, self-alignment of the reflective layer 140 with respect to the light-emitting element 120 can be achieved. Even if the light-emitting element 120 has an unexpected position offset during the bonding process with the substrate 100, it will not affect the alignment accuracy of the reflective layer 140.

[0104] Next, a micro-lens material layer 160M is formed on the reflective layer 140, and an exposure and development process is performed on the micro-lens material layer 160M using a photomask M2a. Among them, the photomask M2a has an opening OP2a overlapping the light-emitting element 120, and in any direction parallel to the substrate surface 100s, the width of the opening OP2a can be greater than or equal to the width of the light-emitting element 120. In this embodiment, the micro-lens material layer 160M is made of, for example, an organic negative photoresist material, but not limited thereto. After the exposure and development process, the micro-lens material layer 160M forms a micro-lens 160A, as Figure 6C shown. In this embodiment, the width of the opening OP2a of the photomask M2a is, for example, greater than the width of the light-emitting element 120. Therefore, the formed micro-lens 160A also covers the protrusion 140p of the reflective layer 140.

[0105] The exposure process of the microlens material layer 160M, for example, adopts a strong exposure method. Therefore, after the development process, the part of the microlens material layer 160M above the forward light-emitting surface 120es1 of the light-emitting element 120 will be retained, while the unexposed or under-exposed parts will be removed. It should be particularly mentioned that the profile of the microlens 160A can be adjusted by the amount of exposure. Since the microlens 160A covers the forward light-emitting surface 120es1 of the light-emitting element 120, its alignment accuracy relative to the light-emitting element 120 can be greatly improved, thereby reducing the influence of the offset error of the light-emitting element 120 during bonding to the substrate 100 on the subsequent film layer structure process.

[0106] Please refer to Figure 6C and Figure 6D , then, a planarizing material layer 150M is formed on the reflective layer 140, and an exposure process is performed on the planarizing material layer 150M to form a planarizing layer 150. The material of the planarizing layer 150, for example, includes inorganic materials (such as silicon oxide, silicon nitride, or silicon oxynitride, but not limited thereto), organic materials (such as polyimide-based resins, epoxy-based resins, or acrylic-based resins, but not limited thereto), or other suitable materials.

[0107] Next, a flank microlens material layer 165M is formed on the planarizing layer 150, and an exposure and development process is performed on the flank microlens material layer 165M using a photomask M2b. Among them, the photomask M2b has an opening OP2b overlapping the light-emitting element 120 and the microlens 160A, and in any direction parallel to the substrate surface 100s, the width of the opening OP2b is greater than Figure 6B the width of the opening OP2a of the photomask M2a in Figure 6E . In this embodiment, the flank microlens material layer 165M is, for example, made of an organic negative photoresist material, but not limited thereto. After the exposure and development process, the flank microlens material layer 165M forms a flank microlens 165, as shown in

[0108] The exposure process of the flank microlens material layer 165M, for example, adopts a strong exposure method. Therefore, after the development process, the unexposed or under-exposed parts in the microlens material layer 160M will be removed. It should be particularly mentioned that the profile of the flank microlens 165 can be adjusted by the amount of exposure. In another variant embodiment not shown, the microlens material layer may also include a part located above the microlens 160A and be retained above the microlens 160A after the exposure and development process. That is to say, the adjustment of the surface profile of the microlens 160A overlapping the forward light-emitting surface 120es1 can be carried out simultaneously during the exposure and development process of the flank microlens.

[0109] Please refer to Figure 6EAfter the wing microlenses 165A are formed, a light shielding material layer 180M is formed on the flat layer 150, and the light shielding material layer 180M is exposed and developed using a mask M3. The mask M3 has an opening OP3 overlapping the light emitting element 120, and in any direction parallel to the substrate surface 100s, the width of the opening OP3 is greater than the width of the microlenses 160A and the wing microlenses 165. In the present embodiment, the light shielding material layer 180M is, for example, a negative photoresist, but is not limited thereto. After the exposure and development process, the light shielding material layer 180M is formed as follows: Figure 5 The light shielding layer 180 is shown.

[0110] It is particularly noted that the exposure process of the light shielding material layer 180M is, for example, a weak exposure method. Therefore, after the development process, the portion of the light shielding material layer 180M above the microlens 160A and the wing microlens 165 will be removed, leaving only the portion covering the wing surface 165s of the wing microlens 165. In this way, the light shielding layer 180 can be self-aligned relative to the microlens 160A and the wing microlens 165A. Even if the light emitting element 120 has an unexpected positional offset during the bonding process with the substrate 100, it will not affect the alignment accuracy of the light shielding layer 180.

[0111] Finally, a packaging layer 190 is formed to cover the microlens 160A, the side microlens 165A and the light shielding layer 180. The material of the packaging layer 190 includes, for example, photoresist, resin, silicone or other suitable materials. Figure 5 In the present embodiment, by raising the height of the side micro-lenses 165A relative to the micro-lenses 160A, the forward light extraction efficiency of the display panel 30 can be further improved.

[0112] In summary, in a display panel of an embodiment of the present invention, since the reflective layer has a self-alignment property relative to the light-emitting element during the manufacturing process, the flat surface of the reflective layer will be closer to the substrate surface than the forward light-emitting surface of the light-emitting element. Accordingly, it is possible to effectively avoid the offset error of the light-emitting element when it is bonded to the substrate from affecting the process space of the reflective layer. In addition, by covering the forward light-emitting surface of the light-emitting element with a microlens, in addition to effectively increasing the alignment accuracy of the microlens relative to the light-emitting element, it is also possible to significantly reduce the impact of the offset error of the light-emitting element when it is bonded to the substrate on the subsequent film structure process.

Claims

1. A display panel, characterized in that: include: a substrate; A light emitting element is disposed on the substrate and has a front light emitting surface facing away from the substrate and a side light emitting surface connected to the front light emitting surface; a reflective layer, disposed on the substrate and covering the lateral light-emitting surface of the light-emitting element, the reflective layer having a flat surface facing away from the substrate, wherein the front light-emitting surface of the light-emitting element has a first height relative to a substrate surface of the substrate, the flat surface of the reflective layer has a second height relative to the substrate surface, and the first height is greater than the second height; and A micro lens is arranged on the light emitting element and covers the forward light emitting surface.

2. The display panel according to claim 1, wherein: The reflective layer also has a protruding portion protruding from the flat surface, the protruding portion covers the lateral light-emitting surface, and the microlens covers the protruding portion of the reflective layer.

3. The display panel according to claim 1, wherein: The microlens has a lens width along a direction parallel to the substrate surface and a lens height along a normal direction of the substrate surface, and a ratio of the lens height to the lens width is greater than or equal to 0.2 and less than or equal to 1.

0.

4. The display panel according to claim 3, wherein: The light emitting element has an element width along the direction, and a ratio of the lens width to the element width is greater than or equal to 1.0 and less than or equal to 1.

5.

5. The display panel according to claim 1, wherein: Also includes: A wing microlens is disposed on the reflective layer, wherein the microlens has a side wall surface surrounding the forward light emitting surface, and the wing microlens covers the side wall surface of the microlens.

6. The display panel according to claim 5, wherein: The side micro lens covers the reflective layer and does not overlap the forward light emitting surface of the light emitting element along the normal direction of the substrate surface.

7. The display panel according to claim 5, wherein: A first angle is formed between the side wall surface of the micro lens and the flat surface, a second angle is formed between a side wing surface of the wing micro lens connected to the reflective layer and the flat surface, and the second angle is smaller than the first angle.

8. The display panel according to claim 5, wherein: Also includes: A light shielding layer is disposed on the reflective layer and covers the reflective layer and the side wing surface of the side wing micro lens connected to the reflective layer.

9. The display panel according to claim 1, wherein: Also includes: A flat layer is arranged on the reflective layer, wherein the microlens has a side wall surface surrounding the forward light-emitting surface, and the flat layer covers the side wall surface of the microlens.

10. The display panel according to claim 9, wherein: Also includes: A wing micro lens is disposed on the flat layer and covers the side wall surface of the micro lens.

11. The display panel according to claim 10, wherein: Also includes: A light shielding layer is disposed on the flat layer and covers the flat layer and a wing surface of the wing microlens connecting the reflective layer.

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