Patent Publication Number: US-2022216446-A1

Title: Display panel

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a Divisional Application of the U.S. application Ser. No. 16/692,168, filed Nov. 22, 2019, which claims priority to Taiwan Application Serial Number 108109847, filed Mar. 21, 2019, all of which are herein incorporated by reference in their entireties. 
    
    
     BACKGROUND 
     Field of Invention 
     The present disclosure relates to a display panel. 
     Description of Related Art 
     With the development of technology, light-emitting diodes have become common and widely used in commercial applications. Light-emitting diodes have many advantages, such as low energy consumption and fast switching. Therefore, conventional light-emitting elements have gradually been replaced by light-emitting diode light sources. Light-emitting diode technology has also begun to develop in display technology. For example, display technology for forming a light-emitting diode and using the light-emitting diode as a pixel has been developed in recent years. 
     To this, in response to the development of organic light-emitting diodes, organic light-emitting diodes have been further applied to display technology. The display device using the organic light-emitting diode may display images without the backlight module, so that the display device may display a better quality black image, and may also be designed to be thinner and lighter. In view of this, the issues related to the display device applying the organic light-emitting diode have become one of the research and development directions in the current related fields. 
     SUMMARY 
     An embodiment of the present disclosure provides a display panel having a non-rectangular display region. The display panel includes a substrate, a pixel definition layer, a first organic material layer, and a second organic material layer. The pixel definition layer is disposed on the substrate, and defines a first pixel area and a second pixel area on the substrate. The first organic material layer is disposed in the first pixel area and has a first light-emitting region. The second organic material layer is disposed in the second pixel area and has a second light-emitting region. The first organic material layer and the second organic material layer have the same material and the same vertical projection area on the substrate, and the vertical projection area of the first light-emitting region on the substrate is smaller than the vertical projection area of the second light-emitting region on the substrate. 
     With the above configuration, the organic material layer having the first portion and the second portion may be used to define the boundary of the display region. In the case where the interface between the first portion and the second portion is a curved surface or an arc surface, the display region may be made to be a non-rectangular pattern. That is, the display panel may present a non-rectangular display region without using additional shields. 
     It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawings as follows: 
         FIG. 1A  is a schematic top view showing a display panel according to a first embodiment of the present disclosure; 
         FIG. 1B  is a schematic cross-sectional view of the line segment  1 B- 1 B′ of  FIG. 1A ; 
         FIG. 2A  is a top view showing the manufacturing method of the display panel in the manufacturing stage according to the first embodiment of the present disclosure; 
         FIG. 2B  is a schematic cross-sectional view of the line segment  2 B- 2 B′ of  FIG. 2A ; 
         FIG. 3A  is a top view showing the manufacturing method of the display panel in the manufacturing stage according to the first embodiment of the present disclosure; 
         FIG. 3B  is a schematic cross-sectional view of the line segment  3 B- 3 B′ of  FIG. 3A ; 
         FIG. 4  is a schematic top view showing a display panel according to a second embodiment of the present disclosure; 
         FIG. 5  is a top view showing the manufacturing method of the display panel in the manufacturing stage according to the third embodiment of the present disclosure; and 
         FIG. 6  is a top view showing the manufacturing method of the display panel in the manufacturing stage according to the fourth embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments of the present disclosure are disclosed in the following drawings, and for the sake of clarity, the practical details are also discussed in the following description. However, it should be understood that these practical details are not intended to limit the present disclosure. That is, in some embodiments of the present disclosure, these practical details are not necessary. In addition, some of the conventional structures and elements are shown in the drawings in a simplified schematic manner in order to simplify the drawings. 
     The words “first,” “second,” “third,” etc. are used herein to describe various elements, components, regions, and layers. However, these elements, components, regions, and layers should not be limited by these terms. These terms are used to identify a single element, component, region, or layer. Thus, a singular element, component, region, or layer may be hereinafter referred to as a second element, component, region, layer, without departing from the spirit of the present disclosure. 
     As used herein, “about,” “approximately” or “substantially” includes the values and average values within acceptable ranges of the particular value determined by one of ordinary skill in the art, in view of the discussion, considering the measurement and the specific number of errors associated with the measurement (i.e., the limits of the measurement system). For example, “about” or “substantially” may mean within one or more standard deviations of the value, such as within ±30%, ±20%, ±10%, ±5%. 
     The display panel of the present disclosure may form a display region by using light-emitting elements, wherein the organic light-emitting element may provide a non-rectangular display region after the modification process, wherein the “non-rectangular” may be an ellipse, a triangle, a polygon with four or more edges. 
     Refer to  FIGS. 1A and 1B ,  FIG. 1A  is a schematic top view showing a display panel  100 A according to a first embodiment of the present disclosure, and  FIG. 1B  is a schematic cross-sectional view of the line segment  1 B- 1 B′ of  FIG. 1A . The display panel  100 A includes a substrate  110 , a first electrode layer  120 , a pixel definition layer  130 , a plurality of light-emitting elements  140 , and a second electrode layer  160 . In some embodiments, the substrate  110  may be a thin film transistor array substrate, and the thin film transistor array substrate may have a thin film transistor array configured by a plurality of thin film transistors. The thin film transistor may be used as a switching element in the display panel  100 A. In some other embodiments, the substrate  110  may be a circuit layer substrate, and the circuit layer substrate may have lines electrically connected to the driving element. 
     The first electrode layer  120  is disposed on the substrate  110 , and the first electrode layer  120  may include a plurality of blocks, such as the first block  122  and the second block  124 . The first block  122  and the second block  124  may be separated from each other, such that the first block  122  and the second block  124  may be respectively applied with different voltages. In some embodiments, the first block  122  and the second block  124  of the first electrode layer  120  may be electrically connected to different thin film transistors, so that the act of applying a voltage to the first block  122  may be independent to the act of applying a voltage to the second block  124 . In some embodiments, the first block  122  and the second block  124  of the first electrode layer  120  may be electrically connected to different lines, so that the act of applying a voltage to the first block  122  is still independent to the act of applying a voltage to the second block  124 . The plurality of blocks of the first electrode layer  120  may be formed by patterning the same conductive layer, where the conductive layer may include a metal material such as aluminum, molybdenum, silver, or combinations thereof. 
     The pixel definition layer  130  is disposed on the substrate  110  and partially covers the first electrode layer  120 . The pixel definition layer  130  may be located between the plurality of blocks of the first electrode layer  120 . For example, the pixel definition layer  130  may be located between the first block  122  and the second block  124  of the first electrode layer  120 , such that the first block  122  and the second block  124  are separated by the pixel definition layer  130 . The pixel definition layer  130  may define a plurality of pixel regions on the substrate  110 , such as the first pixel region  132  and the second pixel region  134  of  FIG. 1B . Each pixel region may correspond to a different block of the first electrode layer  120 . For example, the vertical projections of the first pixel region  132  and the second pixel region  134  on the substrate  110  overlap the first block  122  and the second block  124  of the first electrode layer  120 , respectively. The material of the pixel definition layer  130  may be an organic material or an inorganic material, such as epoxy resin, yttrium oxide (SiOx), tantalum nitride (SiNx), a composite layer composed of yttrium oxide and tantalum nitride, or other suitable dielectric material. 
     The plurality of light-emitting elements  140  are respectively disposed on different blocks of the first electrode layer  120 , such that the first electrode layer  120  may serve as a driving electrode of the light-emitting element  140 . The plurality of light-emitting elements  140  are respectively located in different pixel regions. Each light-emitting element  140  includes an organic material layer  141 , and the plurality of light-emitting elements  140  may be configured in an array form. The organic material layer  141  of the light-emitting element  140  is biased to form a light-emitting region, and the light-emitting regions may collectively serve as the display region  102  of the display panel  100 A. That is, the plurality of light-emitting elements  140  may be used as light-emitting pixels, and the display region  102  is formed by aggregating, and the boundary contour of the organic material layer  141  of the light-emitting element  140  coincides with the boundary contour of the display region  102 . 
     The second electrode layer  160  is disposed on the pixel definition layer  130  and covers the plurality of light-emitting elements  140  to serve as a common electrode. The second electrode layer  160  may include a transparent conductive material, such as indium tin oxide, indium zinc oxide, zinc oxide, indium gallium zinc oxide or other suitable materials. 
     To facilitate understanding, the light-emitting element  140  in  FIG. 1A  is shown to have the same mesh bottom as the organic material layer  141  of  FIG. 1B . In addition, for convenience of explanation, the following description will be made with the first light-emitting element  142  and the second light-emitting element  144  in the light-emitting element  140 . The structural description of the first light-emitting element  142  or the second light-emitting element  144  may be applied to other corresponding light-emitting elements  140 . Further, the plurality of light-emitting elements  140  may respectively provide different color lights in accordance with the arrangement order. For example, the first light-emitting element  142  of  FIG. 1A  may provide red color light, the second light-emitting element  144  of  FIG. 1A  may provide green color light, and then, from the light-emitting element  140  of  FIG. 1A , along the left direction, the color lights provided by the plurality of light-emitting elements  140  may be blue, red, and green in order, and are repeatedly arranged according to this rule. That is, in the lateral direction, the light-emitting elements  140  may be periodically arranged in a group of three colors (blue, red, green). In the longitudinal direction, the light-emitting element  140  may be a color light that provides the same color. 
     The first light-emitting element  142  is located within the first pixel region  132  and may serve as a pixel on the boundary of the display region  102 , that is, the first light-emitting element  142  is located at the edge of the display region  102 . The first light-emitting element  142  is disposed between the first block  122  of the first electrode layer  120  and the second electrode layer  160  and contacts the first block  122  of the first electrode layer  120  and the second electrode layer  160 . When the first block  122  of the first electrode layer  120  is applied with a voltage by the substrate  110 , the first light-emitting element  142  may generate electroluminescence by the bias voltage generated by the first block  122  of the first electrode layer  120  and the second electrode layer  160 . 
     In some embodiments, the first light-emitting element  142  may be a multi-layered structure. For example, the first light-emitting element  142  may include a first carrier transport layer  152 , a first organic material layer  146 , and a second carrier transport layer  154  that are sequentially stacked from the first block  122  of the first electrode layer  120 . When the first electrode layer  120  and the second electrode layer  160  are respectively an anode and a cathode, the first carrier transport layer  152  and the second carrier transport layer  154  may respectively be a hole transport layer and an electron transport layer. The present disclosure is not limited thereto. Although the first light-emitting element  142  of  FIG. 1B  is illustrated as a three-layer structure, in some other embodiments, the first light-emitting element  142  may further include at least one layer of a carrier barrier layer, at least one layer of carrier injection layer, or combinations thereof. 
     The first organic material layer  146  of the first light-emitting element  142  includes a first portion  148  and a second portion  150  that are connected to each other. The first portion  148  and the second portion  150  may be formed of the same organic layer body, and then the first portion  148  may be modified so that the material properties of the first portion  148  are different from the material properties of the second portion  150 . The material properties include a minimum turn-on voltage, energy gap, impedance, and/or carrier mobility. In some embodiments, the minimum turn-on voltage of the first portion  148  is different from the minimum turn-on voltage of the second portion  150 , and the ratio of the minimum turn-on voltage of the first portion  148  to the minimum turn-on voltage of the second portion  150  is between 2 and 7. In some embodiments, the energy gap of the first portion  148  may be different from the energy gap of the second portion  150 . For example, the energy gap of the first portion  148  may be substantially different from the energy gap of the second portion  150  by 0.8 eV to 1.2 eV. In some embodiments, the impedance of the first portion  148  may be different from the impedance of the second portion  150 . For example, the ratio of the impedance of the first portion  148  to the impedance of the second portion  150  may be between 8 and 12. In some embodiments, the carrier mobility of the first portion  148  may be different from the carrier mobility of the second portion  150 . For example, the ratio of the carrier mobility of the first portion  148  to the carrier mobility of the second portion  150  may be between 8 and 12. 
     On the other hand, since the first portion  148  and the second portion  150  of the first organic material layer  146  are formed of the same organic layer body, the first portion  148  and the second portion  150  of the first organic material layer  146  may have substantially the same kind of organic molecules. In some embodiments, the modified first portion  148  and the second portion  150  may have the same kind of organic light-emitting material. In some other embodiments, the second portion  150  can have an organic light-emitting material, while the modified first portion  148  has a derivative of the organic light-emitting material of the second portion  150 . For example, the first portion  148  and the second portion  150  may be formed of the same organic polymer layer body. After modifying the first portion  148 , the organic light-emitting materials of the first portion  148  and the second portion  150  may have the same main chain, while the organic light-emitting materials of the first portion  148  and the second portion  150  have distinct branch chains. In addition, since the first portion  148  and the second portion  150  are formed of the same organic layer body, the first portion  148  and the second portion  150  may have substantially the same thickness. 
     The bias voltage generated by the first block  122  of the first electrode layer  120  and the second electrode layer  160  may generate illumination by the electron-hole recombination mechanism in the first organic material layer  146  of the first light-emitting element  142 . Since the material properties of the first portion  148  and the second portion  150  are different, the brightness of the first portion  148  may be different from the brightness of the second portion  150  when a bias voltage is applied to the first light-emitting element  142 . For example, under the bias voltage of the first light-emitting element  142 , the illuminating brightness of the first portion  148  may be less than the illuminating brightness of the second portion  150 . More specifically, when the bias voltage applied to the first light-emitting element  142  may cause the second portion  150  to illuminate and may not cause the first portion  148  to illuminate, the illuminance of the first portion  148  approaches zero. 
     Since the second portion  150  may emit light and the first portion  148  cannot emit light when the first organic material layer  146  is biased, the boundary of the display region  102  can be defined by the first organic material layer  146 . That is, the interface between the first portion  148  and the second portion  150  of the first organic material layer  146  is the boundary of the display region  102 . In some embodiments, the interface between the first portion  148  and the second portion  150  of the first organic material layer  146  in the direction perpendicular to the substrate  110  is a curved surface or an arc surface. Therefore, the display panel  100 A can present a curved or arc display region  102  without using an additional shield. 
     The second light-emitting element  144  is located within the second pixel region  134  and may serve as a pixel on the boundary of the display region  102 , that is, the second light-emitting element  144  is located distant from the edge of the display region  102  with respect to the first light-emitting element  142 . The second light-emitting element  144  is disposed between the second block  124  of the first electrode layer  120  and the second electrode layer  160  and contacts the second block  124  of the first electrode layer  120  and the second electrode layer  160 . When the second block  124  of the first electrode layer  120  is applied with a voltage by the substrate  110 , the second light-emitting element  144  may generate electroluminescence by the bias voltage generated by the second block  124  of the first electrode layer  120  and the second electrode layer  160 . Since the act of applying a voltage to the first block  122  may be independent of the act of applying a voltage to the second block  124 , the illumination intensity of the first light-emitting element  142  and the illumination intensity of the second light-emitting element  144  may be independently controlled by the first block  122  and the second block  124  of the first electrode layer  120 . 
     In some embodiments, the second light-emitting element  144  may be a multi-layered structure, and the number of layers thereof may be the same as that of the first light-emitting element  142 . For example, the second light-emitting element  144  may include a third carrier transport layer  158 , a second organic material layer  156 , and a fourth carrier transport layer  159  that are sequentially stacked from the second block  124  of the first electrode layer  120 . When the first electrode layer  120  and the second electrode layer  160  are respectively an anode and a cathode, the third carrier transport layer  158  and the fourth carrier transport layer  159  may respectively be a hole transport layer and an electron transport layer. Similarly, the present disclosure is not limited thereto, although the second light-emitting element  144  of  FIG. 1B  is illustrated as a three-layer structure, in some other embodiments, the second light-emitting element  144  may further include at least one layer of a carrier barrier layer, at least one layer of carrier injection layer, or combinations thereof. 
     The layer body of the first light-emitting element  142  and the second light-emitting element  144  having the same function (for example, lifting the carrier transmission benefit) may be formed by the same process and formed of the same material. For example, the first carrier transport layer  152  of the first light-emitting element  142  and the third carrier transport layer  158  of the second light-emitting element  144  may be formed by the same process and formed of the same material, and thus have substantially the same thickness. Similarly, the second carrier transport layer  154  of the first light-emitting element  142  and the fourth carrier transport layer  159  of the second light-emitting element  144  may be formed by the same process and formed of the same material, and thus have substantially the same thickness. 
     In addition, the first organic material layer  146  and the second organic material layer  156  may have the same distribution area, but have different illumination region areas. Further, under the bias voltage, since the first portion  148  of the first organic material layer  146  cannot emit light as the second portion  150 , the area of the light-emitting region of the second organic material layer  156  (hereinafter referred to as the second light-emitting region) will be larger than the area of the light-emitting region of the first organic material layer  146  (hereinafter referred to as the first light-emitting region). That is, although the vertical projection areas of the first organic material layer  146  and the second organic material layer  156  on the substrate  110  are substantially the same, but the vertical projection area of the first light-emitting region of the first organic material layer  146  on the substrate  110  is smaller than that of the second light-emitting region of the second organic material layer  156 , such that the first light-emitting element  142  including the first organic material layer  146  is suitable to be a pixel on the boundary of the display region  102 , and the second light-emitting element  142  including the second organic material layer  156  is suitable to be a pixel within the boundaries of the display region  102 . That is, a vertical projection position of the first organic material layer  146  on the substrate  110  is adjacent to an edge of the substrate  110  with respect to a vertical projection position of the second organic material layer  156  on the substrate  110 . 
     On the other hand, as illustrated in  FIG. 1A , the first light-emitting element  142  and the light-emitting element  140 ′ may have the same properties by including the same material (for example, the same organic light-emitting material, and the formed thicknesses of the organic light-emitting materials are also substantially the same), and therefore are used to provide the same color light, for example, to provide red light. For the first light-emitting element  142  and the light-emitting element  140 ′, the first light-emitting element  142  is located at an edge of the display region  102 , and the light-emitting element  140 ′ is located distant from the edge of the display region  102  with respect to the first light-emitting element  142 , and the light-emitting region of the light-emitting element  142  is smaller than that of the light-emitting element  140  due to the presence of the first portion  148  that cannot emit light. In some embodiments, a ratio of an illuminating area of the first light-emitting pixel to an illuminating area of the second light-emitting pixel is greater than 0 and less than or equal to 0.95. 
     The method of manufacturing the display panel  100 A and the steps of performing the modification process will be described below. Refer to  FIGS. 2A and 2B ,  FIG. 2A  is a top view showing the manufacturing method of the display panel  100 A in the manufacturing stage according to the first embodiment of the present disclosure, and  FIG. 2B  is a schematic cross-sectional view of the line segment  2 B- 2 B′ of  FIG. 2A . As shown in  FIGS. 2A and 2B , the first electrode layer  120  may be formed on the substrate  110 , and the first electrode layer  120  may be patterned into a plurality of blocks, such as the first block  122  and the second block  124 . The pixel definition layer  130  may be formed on the substrate  110  and partially covers the first electrode layer  120 . The formed pixel definition layer  130  may have a plurality of openings  138  to define a plurality of pixel regions, such as a first pixel region  132  and a second pixel region  134 . 
     Next, a plurality of light-emitting elements  140 , such as a first light-emitting element  142  and a second light-emitting element  144 , may be formed in the plurality of openings  138  of the pixel definition layer  130 , respectively. In this stage of fabrication, the structures of the different light-emitting elements  140  may be similar or even identical to each other, for example, each of the light-emitting elements  140  includes an organic material layer  141  and two carrier transport layers  143  and  145 . Further, for the light-emitting element  140  that provides the same-color light (for example, red), for example, the first light-emitting element  142  and the light-emitting element  140 ′ of  FIG. 2A , in addition to the identical three-layer structure, even the material and thickness of the corresponding layer bodies (for example, the organic material layer or the carrier transport layer included in each of the first light-emitting element  142  and the light-emitting element  140 ′) are also substantially the same. In some embodiments, the material and thickness of the organic material layer or the carrier transport layer respectively provided for the light-emitting elements  140  that provide the distinct lights (for example, red and green) may be identical. After the light-emitting element is formed, the second electrode layer  160  may be formed on the light-emitting element  140  such that the second electrode layer  160  covers the light-emitting element  140 . After this stage, when a bias voltage is applied to the light-emitting element  140  through the first electrode layer  120  and the second electrode layer  160 , the light-emitting element  140  can be caused to generate electroluminescence. 
     Refer to  FIGS. 3A and 3B ,  FIG. 3A  is a top view showing the manufacturing method of the display panel  100 A in the manufacturing stage according to the first embodiment of the present disclosure, and  FIG. 3B  is a schematic cross-sectional view of the line segment  3 B- 3 B′ of  FIG. 3A . The manufacturing phase of  FIG. 3A  continues after the manufacturing phase of  FIG. 2A . As shown in  FIGS. 3A and 3B , a mask  170  having a circular shape and having an arc boundary contour may be disposed on the second electrode layer  160 . In some other embodiments, a protective layer may be formed on the second electrode layer  160 , and then the mask  170  may be disposed on the protective layer. 
     After disposing the mask  170 , a portion of the light-emitting element  140  may be completely shielded by the mask  170 , while another portion of the light-emitting element  140  are partially shielded by the mask  170 , and thus a portion of the area may be exposed. For example, a portion of the first organic material layer  146  of the first light-emitting element  142  is shielded by the mask  170 , while another portion of the first organic material layer  146  of the first light-emitting element  142  is not shielded by the mask  170  and thus is exposed. In addition, the second organic material layer  156  of the second light-emitting element  144  is completely shielded by the mask  170 . 
     Next, the display panel  100 A can be irradiated with ultraviolet light  172  to perform a modification process. During the illumination of the ultraviolet light  172 , the ultraviolet light  172  illuminates the mask  170  and the portion of the organic material layer that is not shielded and exposed by the mask  170 . For example, the portion of the first organic material layer  146  of the first light-emitting element  142  that is not shielded by the mask  170  is exposed to ultraviolet light  172 . 
     For organic materials that are exposed to ultraviolet light  172 , ultraviolet light  172  irradiation may cause photochemical reactions of organic molecules, such as fragmentation, dimerization, photo-oxidation, where the photooxidation may in turn lead to exciton quenching. That is, there is a difference between the organic material irradiated by the ultraviolet light  172  and the organic material not irradiated by the ultraviolet light  172 , wherein the difference may be a difference in energy gap, impedance or carrier mobility, so that the organic material irradiated by the ultraviolet light  172  and the organic material not irradiated by the ultraviolet light  172  exhibit different luminescence performances at the same bias voltage. For example, a portion of the first organic material layer  146  of the first light-emitting element  142  that is irradiated by the ultraviolet light  172  may become the first portion  148  described above, and the first organic material layer  146  of the first light-emitting element  142  that is not irradiated by the ultraviolet light is the second portion  150  described above, wherein the first portion  148  and the second portion  150  exhibit different luminescence performances at the same bias voltage. In other words, through the modification process, the brightness provided by the first portion  148  when biased can be made less than the brightness provided by the second portion  150  when biased. Alternatively, the second portion  150  may emit light and the first portion  148  may not emit light under the same bias voltage. After the manufacturing stage is finished, the mask  170  can be removed to obtain the structure as shown in  FIG. 1A . 
     On the other hand, after irradiating the ultraviolet light  172 , the boundary position of the display region  102  (see  FIG. 1A ) can be defined by “the interface between the normal light-emitting portion and the abnormal light-emitting portion in the organic material layer,” and the defined display region has the same shape as the mask  170 . That is, since the organic material shielded by the mask  170  can normally emit light when biased, the shape of the display region is correspondingly the shape of the mask  170 . In the case where the mask  170  used in  FIG. 3A  is circular and has an arc boundary contour, the defined display region will also be the same circular shape and the same arc boundary contour as the mask  170 . In some other embodiments, other patterned masks, such as a pattern with curved or arc boundaries (or masks with distinct boundary contours), may be used to define the display region  102  (see  FIG. 1A ) as having a curved boundary or an arc boundary. 
     In addition, since the defined non-rectangular display region  102  (see  FIG. 1A ) is formed by the mask  170  and the ultraviolet light  172  irradiation, the light-emitting elements  140  at the boundary and inside the boundary of the display region (see  FIG. 1A ) may exhibit better uniformity. For example, for the first light-emitting element  142  and the light-emitting element  140 ′ that provide the same color light (for example, red), the first light-emitting element  142  and the light-emitting element  140 ′ are simultaneously formed at the same manufacturing stage, the manufacturing process parameters thereof are substantially the same and thus the illuminating performance are the same, thereby preventing the display panel  100 A from having a non-uniform brightness condition. 
     Please refer to  FIG. 3A . According to the foregoing, for the organic material layer  141  partially shielded by the mask  170 , it may coincide with the boundary contour of the different positions of the mask  170 . For example, the third light-emitting element  180  of the display panel  100 A is adjacent to the first light-emitting element  142  and is separated from the first light-emitting element  142  by the pixel definition layer  130 . The third light-emitting element  180  includes a portion of the third organic material layer  182  that is exposed to ultraviolet light  172  (see  FIG. 3B ) to form a third portion  184  and a fourth portion  186  that are connected to each other. In the stage of irradiating by ultraviolet light  172  (see  FIG. 3B ), the third portion  184  of the third organic material layer  182  is irradiated by ultraviolet light  172  (see  FIG. 3B ), while the fourth portion  186  is not irradiated by ultraviolet light  172  (see  FIG. 3B ). Therefore, when the third organic material layer  182  is biased, the luminance of the third portion  184  may be smaller than that of the fourth portion  186 . This mechanism may be similar to the first organic material layer  146 , and the details thereof are not described herein again. 
     The interface between the first portion  148  and the second portion  150  of the first organic material layer  146  may overlap with the boundary contour of the mask  170  at one location, while the interface between the third portion  184  and the fourth portion of the third organic material layer  182  will overlap the boundary contour of the other portion of the mask  170  at another location. That is, in the case where the mask  170  is circular, the interface between the first portion  148  and the second portion  150  of the first organic material layer  146  and the interface between the third portion  184  and the fourth portion  186  of the third organic material layer  182  overlap the boundary contour of the circle at different locations. In some other embodiments, the mask  170  can be other patterns, such as ovals, triangles, or polygons having more than four edges, and the interfaces described above still overlap the boundary contour of the patterns at different locations. 
     That is, the extension line of the boundary line connecting the first portion  148  and the second portion  150  of the first organic material layer  146  coincides with the extension line of the boundary line connecting the third portion  184  and the fourth portion  186  of the third organic material layer  182 . “The extension line of the boundary line” refers to the extension according to the rule of the contour change of the pattern. For example, when the boundary line connecting the first portion  148  and the second portion  150  of the first organic material layer  146  and the boundary line connecting the third portion  184  and the fourth portion  186  of the third organic material layer  182  are line segments in the same direction, their extension lines will be two lines that coincide. When the boundary line connecting the first portion  148  and the second portion  150  of the first organic material layer  146  and the boundary line connecting the third portion  184  and the fourth portion  186  of the third organic material layer  182  are line segments of the same circle, their extension lines will be two arcs with the same curvature. 
     Reference is made to  FIG. 4  again, which is a schematic top view of the display panel  100 B according to the second embodiment of the present disclosure. At least one difference between the present embodiment and the first embodiment is that the display region  102  of the display panel  100 B of the present embodiment has a ring shape. Further, the outer edge boundary and the inner edge boundary of the display region  102  of the display panel  100 B are concentric circles. In the manufacturing stage of the display panel  100 B of the present embodiment, the light-emitting element  140  formed in the central region may be omitted. Also, in the stage of ultraviolet light irradiation, the mask may have a ring shape, so that the defined display region  102  will be the same ring shape as the mask. Therefore, in addition to that the light-emitting elements  140  arranged in the outermost side of the light-emitting element array may be “partially illuminable (for example, the second portion  150  of the first embodiment) and the other portion may not emit light (for example, the first portion  148  of the first embodiment),” the light-emitting elements  140  arranged at the innermost side of the light-emitting element array (i.e., the light-emitting elements  140  closest to the central region) may also be “partially illuminable and the other portion being unable to emit light.” 
     It should be understood that the shape of the display region of the display panel of the present disclosure is not limited to the above embodiment. In other embodiments, the display area of other non-rectangular patterns may be formed by changing the shape of the mask. Furthermore, the outer edge boundary and the inner edge boundary of the display region may be different patterns, for example, the outer edge boundary and the inner edge boundary may be elliptical and circular, respectively. 
     The above embodiments achieve the modification effect by irradiating ultraviolet light. However, the present disclosure is not limited thereto.  FIG. 5  is a cross-sectional view showing the manufacturing method of the display panel  100 C in the manufacturing stage according to the third embodiment of the present disclosure. The cross-sectional position of  FIG. 5  corresponds to that of  FIG. 3B . 
     As shown in  FIG. 5 , after forming the organic material layer  141  of the light-emitting element  140 , the mask  190  is first disposed on the display panel  100 C, and a portion of the organic material layer  141  is completely shielded by the mask  190 . Another portion of the organic material layer  141  is partially shielded by the mask  190 , and thus a portion of the organic material layer  141  is exposed. In this embodiment, the mask  190  may be a protective layer formed on the pixel definition layer  130  and the organic material layer  141 , wherein the material of the protective layer may be an organic material or an inorganic material, such as an epoxy resin, a cerium oxide (SiOx), tantalum nitride (SiNx), a composite layer composed of tantalum oxide and tantalum nitride or other suitable dielectric material. 
     Then, the display panel  100 C and the mask  190  thereon are placed in a high-humidity environment, so that the organic material layer  141  not covered by the mask  190  is modified by water and oxygen in the environment. For example, the water-oxygen environment  192  may undergo an oxidation reaction with the organic material layer  141 , wherein the oxidation reaction involves a photochemical reaction and an electrochemical reaction, so that the material properties of the organic material layer  141  not covered by the mask  190  are different from those of the organic material layer  141  covered by the mask  190 . Therefore, a part of the light-emitting element  140  can be formed to have a normal light-emitting portion and an abnormal light-emitting portion by the water-oxygen environment  192 . For example, the first light-emitting element  142  can be configured to form the first organic material layer  146  to have the first portion  148  and the second portion  150  as described above. 
       FIG. 6  is a cross-sectional view showing the manufacturing method of the display panel  100 C in the manufacturing stage according to the fourth embodiment of the present disclosure. The cross-sectional position of  FIG. 6  corresponds to that of  FIG. 3B . At least one difference between the present embodiment and the third embodiment is that in the present embodiment, after the second electrode layer  160  is formed, the mask  194  is further provided on the display panel  100 D. A portion of the second electrode layer  160  may be completely shielded by the mask  194 , while another portion of the second electrode layer  160  is partially shielded by the mask  194 , and thus a portion of the second electrode layer  160  is exposed, as indicated by the labeled second electrode layer  160 ′. 
     Then, the display panel  100 D and the mask  194  thereon are placed in a high-humidity environment, thereby chemically reacting the exposed second electrode layer  160 ′ by the water-oxygen environment  196 , thereby oxidizing the metal and generating hydrolyzed derivatives. The generated hydrolyzed derivative may further react with the inner layer of the lower light-emitting element  140  and cause crystal deformation, thereby forming the part of the light-emitting element  140  to have the normal light-emitting portion and the abnormal light-emitting portion, for example, the first organic material layer  146  of the first light-emitting element  142  can be formed into the aforementioned first portion  148  and second portion  150  by this mechanism. 
     In summary, the display panel of the present disclosure includes a plurality of light-emitting elements, wherein the light-emitting elements can be arranged in an array to define a display region of the display panel. The organic material layer of the light-emitting element positioned at the outermost side of the array may be formed to have a portion that can normally emit light and a portion that cannot emit light normally, and the interface between the portion that can normally emit light and the portion that cannot normally emit light is the boundary of the display region. In the organic material layer of the light-emitting element at the outermost side of the array, the interface between the portion that can normally emit light and the portion that cannot normally emit light may be curved or arch, such that the display region of the display panel is a non-rectangular pattern. That is, the display panel may present a non-rectangular display region without using additional shields. Since the shield is not used, the layer configuration of the surface of the display panel can be facilitated. On the other hand, since the non-rectangular display region is realized by modifying the organic material layer of the light-emitting element, the light-emitting element can be formed under the same conditions at the same manufacturing stage, thereby preventing the display panel from having non-uniform brightness. 
     Although the present disclosure has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein. It will be apparent to those skilled in the art that various modifications and variations may be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims.