Display panel having first, second, and third electrodes

This application claims the priority benefit of Taiwan application serial no. 107122649, filed on Jun. 29, 2018. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification.

The invention relates to a display panel. More particularly, the invention relates to a display panel including a black matrix.

A black matrix in a display panel generally includes a plurality of openings corresponding to a plurality of pixel regions, so as to accommodate color filter layers. Nevertheless, the openings of the black matrix are subject to limitation of a minimum size owing to process limitation. As such, size of pixels cannot be further reduced, and development of high resolution of the display panels is thus affected.

At least one embodiment of the invention provides a display panel capable of reducing size of pixels.

In at least one embodiment of the invention, a display panel includes a scan line, a first data line, a second data line, a first switching element, a second switching element, a first electrode, two second electrodes, a third electrode, a black matrix, and a plurality of color filter layers. The first data line and the second data line substantially extend in a first direction. The scan line substantially extends in a second direction. The first switching element is electrically connected to the scan line and the first data line. The second switching element is electrically connected to the second data line. The first electrode includes at least two first openings. The two second electrodes are electrically connected to the first switching element and the second switching element respectively through the at least two first openings. The third electrode includes two first body portions, a second body portion, and at least two branch portions. The two first body portions substantially extend in the first direction. The second body portion is located between the two first body portions and substantially extends in the first direction. The at least two branch portions are respectively connected to one of the two first body portions and the second body portion. The black matrix includes a plurality of second openings. The black matrix substantially shields at least a portion of the first data line. Two neighboring color filter layers are disposed corresponding to one of the plurality of second openings and form an overlapped structure. The overlapped structure substantially shields at least a portion of the second data line in the second opening.

To sum up, in the at least one embodiment of the invention, two color filter layers are designed to be disposed in one second opening of the black matrix, and a portion of the second data line which is not covered by the black matrix is shielded by both of the overlapped structure and the second body portion of the third electrode, and thereby, size of pixels is reduced and a light leakage is prevented.

To make the aforementioned characteristics and advantages more comprehensible, several embodiments accompanied with drawings are described in detail as follows.

The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.

FIG. 1 is a schematic top view of a display panel according to an embodiment of the invention.

FIG. 2A is an enlarged view of a region R of the display panel in FIG. 1 .

FIG. 2B is a schematic top view of the display panel of FIG. 2A with a black matrix and a plurality of color filter layers omitted.

FIG. 2C is a schematic top view of a first electrode and a third electrode in FIG. 2B .

FIG. 3 is a schematic cross-sectional view taken along a cross-sectional line A-A′ in FIG. 2A .

FIG. 4 is a schematic top view of a display panel according to another embodiment of the invention.

The invention will be described more comprehensively below with reference to the drawings for the embodiments. However, the invention may also be implemented in different forms rather than being limited by the embodiments described in the invention. Thicknesses of layers and regions in the drawings are enlarged for clarity. The same reference numbers are used in the drawings and the description to indicate the same or like parts, which are not repeated in the following embodiments. Further, the language used to describe the directions such as up, down, left, right, front, back or the like in the reference drawings is regarded in an illustrative rather than in a restrictive sense. As such, the directional terminology is used for purposes of illustration and is in no way limiting.

FIG. 1 is a schematic top view of a display panel according to an embodiment of the invention. FIG. 2A is an enlarged view of a region R of the display panel in FIG. 1 . FIG. 2B is a schematic top view of the display panel of FIG. 2A with a black matrix and a plurality of color filter layers omitted. FIG. 2C is a schematic top view of a first electrode and a third electrode in FIG. 2B . FIG. 3 is a schematic cross-sectional view taken along a cross-sectional line A-A′ in FIG. 2A .

With reference to FIG. 1 , FIG. 2A , FIG. 2B , FIG. 2C , and FIG. 3 together, in this embodiment, a display panel 10 includes a scan line SL, first data lines DL 1 , a second data line DL 2 , a first switching element T 1 , a second switching element T 2 , a first electrode CM 1 , two second electrodes PE 1 and PE 2 , a third electrode CM 2 , a black matrix BM, and a plurality of color filter layers CF 1 , CF 2 , and CF 3 . In addition, the display panel 10 may further includes a first substrate 100 , a second substrate 200 , insulation layers IL 1 and IL 2 , planarization layers PL 1 and PL 2 , and a display medium layer 140 . For illustrative convenience, only a partial region of the display panel 10 is shown in FIG. 1 . A person having ordinary skill in the art may understand a structure or a layout of the display panel 10 according to the following embodiments.

In this embodiment, the first substrate 100 and the second substrate 200 are disposed opposite to each other. The material of the first substrate 100 and the second substrate 200 may be glass, quartz, organic polymers, or other suitable materials, or a combination of at least two of the foregoing materials.

In this embodiment, the scan line SL, the first data lines DL 1 , the second data line DL 2 , the first switching element T 1 , the second switching element T 2 , the first electrode CM 1 , the two second electrodes PE 1 and PE 2 , and the third electrode CM 2 are disposed on the first substrate 100 .

The first data lines DL 1 and the second data line DL 2 substantially extend in a first direction E 1 and are arranged in a second direction E 2 , and the scan line SL substantially extends in the second direction E 2 . Nevertheless, the invention is not limited thereto. In some embodiments, the second direction E 2 is substantially perpendicular to the first direction E 1 , but the invention is not limited thereto. Although the scan line SL, the first data lines DL 1 , and the second data line DL 2 in this embodiment are exemplified as being straight lines, the invention is not limited thereto. In other embodiments, the scan line SL, the first data lines DL 1 , and the second data line DL 2 may be shaped as a zigzag shape or other shapes. The second data line DL 2 is located between two neighboring first data lines DL 1 . Considering electrical conductivity, the scan line SL, the first data lines DL 1 , and the second data line DL 2 are generally made of metal, but the invention is not limited thereto. In other embodiments, the scan line SL, the first data lines DL 1 , and the second data line DL 2 may be made of other conductive materials (e.g., alloy, metal nitride, metal oxide, metal oxynitride) or a stack layer having metal and the aforesaid conductive materials.

The first switching element T 1 is electrically connected to the scan line SL and the first data line DL 1 . The second switching element T 2 is electrically connected to the scan line SL and the second data line DL 2 . In this embodiment, the first switching element T 1 and the second switching element T 2 are exemplified as being top-gate thin film transistors, but the invention is not limited thereto. The first switching element T 1 and the second switching element T 2 may be bottom-gate thin film transistors or switching elements of other types in other embodiments. In this embodiment, each of the first switching element T 1 and the second switching element T 2 includes two gates, but the invention is not limited thereto. Each of the first switching element T 1 and the second switching element T 2 may include one gate only.

In this embodiment, the first switching element T 1 includes a first gate G 1 A, a second gate G 1 B, a channel layer CH 1 , a source S 1 , and a drain D 1 . The first gate G 1 A and the second gate G 1 B are electrically connected to the scan line SL, and the source S 1 is electrically connected to the first data line DLL The second switching element T 2 includes a first gate G 2 A, a second gate G 2 B, a channel layer CH 2 , a source S 2 , and a drain D 2 . The first gate G 2 A and the second gate G 2 B are electrically connected to the scan line SL, and the source S 2 is electrically connected to the second data line DL 2 . The source S 1 and the source S 2 may electrically connected to the channel layer CH 1 and the channel layer CH 2 respectively through a contact hole H 1 and a contact hole H 2 , and the drain D 1 and the drain D 2 may electrically connected to the channel layer CH 1 and the channel layer CH 2 respectively through a contact hole H 3 and a contact hole H 4 .

The channel layer CH 1 overlaps the first gate G 1 A and the second gate G 1 B. An insulation layer GI may be sandwiched between the channel layer CH 1 and the first gate G 1 A and between the channel layer CH 1 and the second gate G 1 B, so as to separate the channel layer CH 1 from the first gate G 1 A and the second gate G 1 B. The channel layer CH 2 overlaps the first gate G 2 A and the second gate G 2 B. The insulation layer GI is sandwiched between the channel layer CH 2 and the first gate G 2 A and between the channel layer CH 2 and the second gate G 2 B, so as to separate the channel layer CH 2 from the first gate G 2 A and the second gate G 2 B. In this embodiment, the channel layer CH 1 and the channel layer CH 2 are exemplified as being U-shaped, but the invention is not limited thereto. The channel layer CH 1 and the channel layer CH 2 may be shaped as a L shape or other shapes.

In this embodiment, an insulation layer IL 0 is disposed on the first gate G 1 A, the first gate G 2 A, the second gate G 1 B, the second gate G 2 B, and the insulation layer GI. In this embodiment, the first data lines DL 1 and the second data line DL 2 are disposed on the insulation layer IL 0 . In this embodiment, the contact holes H 1 , H 2 , H 3 , and H 4 penetrate the insulation layer IL 0 and the insulation layer GI.

A light-shielding layer SM may be selectively disposed between the channel layer CH 1 and the first substrate 100 or between the channel layer CH 2 and the first substrate 100 , as shown in FIG. 2B . A current leakage problem of the first switching element T 1 and the second switching element T 2 may be solved through the light-shielding layer SM. In this embodiment, the material of the light-shielding layer SM may include any light-shielding material commonly known to people having ordinary skills in the art, e.g., molybdenum, molybdenum-aluminum-molybdenum, titanium-aluminum-titanium, or other metals which do not allow light to pass through or black resin, so as to shield light rays. In other embodiments, the light-shielding layer SM may selectively not to be disposed.

The planarization layer PL 1 is disposed on the first substrate 100 and covers the scan line SL, the first data lines DL 1 , the second data line DL 2 , the first switching element T 1 , and the second switching element T 2 . The planarization layer PL 1 includes, for example, contact holes H 5 and H 6 . In this embodiment, the planarization layer PL 1 may be made of an inorganic material (e.g., silicon oxide, silicon nitride, silicon oxynitride, or a stack layer having at least two of the above materials), an organic material (e.g., polyimide resin, epoxy resin, or acrylic resin), or a combination of both, but the invention is not limited thereto. The planarization layer PL 1 may be a single-layer structure, but the invention is not limited thereto. In other embodiments, the planarization layer PL 1 may be a multi-layer structure. The planarization layer PL 1 provides favorable flatness to facilitate subsequent formation of the first electrode CM 1 .

The first electrode CM 1 is disposed on the planarization layer PL 1 . In this embodiment, the first electrode CM 1 has two first openings O 11 and O 12 . The first opening O 11 , for example, overlaps the contact hole H 5 , and the first opening O 12 , for example, overlaps the contact hole H 6 , but the invention is not limited thereto. The material of the first electrode CM 1 may include a metal oxide conductive material, such as indium tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, indium gallium zinc oxide, other suitable oxides, or a stack layer including at least two of the above.

The insulation layer IL 1 is disposed on the planarization layer PL 1 and covers the first electrode CM 1 . The insulation layer ILL for example, includes contact holes H 7 and H 8 . The contact hole H 7 , for example, overlaps the first opening O 11 and the contact hole H 5 , and the contact hole H 8 , for example, overlaps the first opening O 12 and the contact hole H 6 , but the invention is not limited thereto. The insulation layer IL 1 may be made of an inorganic material (e.g., silicon oxide, silicon nitride, silicon oxynitride, or a stack layer having at least two of the above materials), an organic material (e.g., polyimide resin, epoxy resin, or acrylic resin), or a combination of both, but the invention is not limited thereto. In this embodiment, the insulation layer IL 1 may be a single-layer structure, but the invention is not limited thereto. In other embodiments, the insulation layer IL 1 may be a multi-layer structure.

The two second electrodes PE 1 and PE 2 are disposed on the insulation layer IL 1 . In this embodiment, the second electrode PE 1 is electrically connected to the drain D 1 of the first switching element T 1 , and the second electrode PE 2 is electrically connected to the drain D 2 of the second switching element T 2 . In this embodiment, the second electrode PE 1 is electrically connected to the drain D 1 through the first opening O 11 and the contact holes H 5 and H 7 overlapped with each other, and the second electrode PE 2 is electrically connected to the drain D 2 through the first opening O 12 and the contact holes H 6 and H 8 overlapped with each other. The material of the second electrodes PE 1 and PE 2 may include a metal oxide conductive material, such as indium tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, indium gallium zinc oxide, other suitable oxides, or a stack layer including at least two of the above. Each of the second electrodes PE 1 and PE 2 may include a slit (not shown), but the invention is not limited thereto.

The insulation layer IL 2 is disposed on the insulation layer IL 1 and covers the second electrodes PE 1 and PE 2 . The insulation layer IL 2 may be made of an inorganic material (e.g., silicon oxide, silicon nitride, silicon oxynitride, or a stack layer having at least two of the above materials), an organic material (e.g., polyimide resin, epoxy resin, or acrylic resin), or a combination of both, but the invention is not limited thereto. In this embodiment, the insulation layer IL 2 may be a single-layer structure, but the invention is not limited thereto. In other embodiments, the insulation layer IL 2 may be a multi-layer structure.

The third electrode CM 2 is disposed on the insulation layer IL 2 . In this embodiment, the third electrode CM 2 includes two first body portions 110 A and 110 B, a second body portion 120 , at least two branch portions 130 A and 130 B, and a plurality of opening holes OP. A portion of the first electrode CM 1 overlaps the opening holes OP. In this embodiment, the opening holes OP are exemplified as being trapezoidal-shaped, but the invention is not limited thereto, and the opening holes OP may be shaped as a rectangle, a circle, or other suitable shapes.

The first body portions 110 A and 110 B substantially extend in the first direction E 1 . The first body portions 110 A and 110 B substantially are parallel to an extending direction of the first data line DL 1 . In some embodiments, the first body portion 110 A entirely overlaps the first data line DL 1 . That is, the width of the first body portion 110 A in the second direction E 2 is approximately equal to the width of the first data line DL 1 in the second direction E 2 , and the first body portion 110 A and the first data line DL 1 overlap in an aligned manner. Nevertheless, the invention is not limited thereto. In other embodiments, the first body portions 110 A and 110 B partially overlap two neighboring first data lines DL 1 respectively.

The second body portion 120 is located between the first body portions 110 A and 110 B and substantially extends in the first direction E 1 . The second body portion 120 substantially is parallel to an extending direction of the second data line DL 2 . In some embodiments, the second body portion 120 entirely overlaps the second data line DL 2 . That is, the width of the second body portion 120 in the second direction E 2 is approximately equal to the width of the second data line DL 2 in the second direction E 2 , and the second body portion 120 and the second data line DL 2 overlap in an aligned manner. Nevertheless, the invention is not limited thereto. In other embodiments, the second body portion 120 partially overlaps the second data line DL 2 .

The branch portions 130 A and 130 B are respectively connected to the corresponding first body portions 110 A and 110 B and the second body portion 120 . The branch portion 130 A is connected between the first body portion 110 A and the second body portion 120 , and the branch portion 130 B is connected between the first body portion 110 B and the second body portion 120 . The branch portion 130 A, for example, extends from the first body portion 110 A towards the second body portion 120 , and the branch portion 130 B, for example, extends from the first body portion 110 B towards the second body portion 120 . In some embodiments, the width of the branch portion 130 A gradually decreases in a direction away from the first body portion 110 A, and the width of the branch portion 130 B gradually decreases in a direction away from the first body portion 110 B. In this embodiment, at least one of the branch portions 130 A and 130 B is trapezoidal-shaped or shaped approximately as a trapezoidal structure, which should however not be construed as being limited to the embodiment set forth herein. In other embodiments, the branch portions 130 A and 130 B may be shaped as a triangle or other geometric shapes.

The black matrix BM is disposed on the second substrate 200 . The material of the black matrix BM is, for example, black resin, metal with low reflectivity (e.g., chromium), or other suitable materials. The black matrix BM includes a plurality of second openings O 2 . The second openings O 2 , for example, are rectangular-shaped, which should however not be construed as being limited to the embodiment set forth herein. In this embodiment, the width W 1 of each of the second openings O 2 in the second direction E 2 is 8 microns to 15 microns, and the distance W 2 between two neighboring second openings O 2 in the second direction E 2 is 1 micron to 6 microns, which should however not be construed as being limited to the embodiment set forth herein. In this embodiment, the second openings O 2 , for example, are aligned in the first direction E 1 and the second direction E 2 and thus are arranged along straight lines. The black matrix BM at least shields a portion of the first data line DL 1 and a portion of the scan line SL substantially. In this embodiment, the black matrix BM entirely shields the first data line DL 1 and the scan line SL. Each of the second openings O 2 simultaneously overlap the corresponding second electrodes PE 1 and PE 2 , as shown in FIG. 3 , which should however not be construed as being limited to the embodiment set forth herein.

The color filter layers CF 1 , CF 2 , and CF 3 are disposed on the second substrate 200 . The color filter layers CF 1 , CF 2 , and CF 3 are respectively a red filter layer, a green filter layer, and a blue filter layer, which should however not be construed as being limited to the embodiment set forth herein. In this embodiment, the color filter layers CF 1 arranged in the first direction E 1 have the same color, the color filter layers CF 2 arranged in the first direction E 1 have the same color, and the color filter layers CF 3 arranged in the first direction E 1 have the same color. For instance, the color filter layers CF 1 are arranged in the first direction E 1 to form a first column of color filter layers, the color filter layers CF 2 are arranged in the first direction E 1 to form a second column of color filter layers adjacent to the first column of color filter layers, and the color filter layers CF 3 are arranged in the first direction E 1 to form a third column of color filter layers adjacent to the second column of color filter layers. In this embodiment, two neighboring color filter layers of the color filter layers CF 1 , CF 2 , and CF 3 arranged in the second direction E 2 have different colors.

Two neighboring color filter layers of the color filter layers CF 1 , CF 2 , and CF 3 may form an overlapped structure OS in the second opening O 2 . For instance, a portion of the color filter layer CF 2 covers a portion of the color filter layer CF 1 to form the overlapped structure OS. The overlapped structure OS includes a portion CF 1 _ 1 of the first color filter layer and a portion CF 2 _ 1 of the second color filter layer. The width W 3 of the overlapped structure OS in the second direction E 2 is, for example, 0.5 microns to 10 microns. In this embodiment, the width W 3 of overlapped structure OS in the second direction E 2 is 3 microns. In this embodiment, the overlapped structure OS may shield a portion of the second data line DL 2 , and in this way, the overlapped structure OS and the black matrix BM may shield the second data line DL 2 together. In this embodiment, the width W 3 of the overlapped structure OS in the second direction E 2 and the distance W 2 between two neighboring second openings O 2 in the second direction E 2 may be equal, but the invention is not limited thereto.

The planarization layer PL 2 is disposed on the second substrate 200 and covers the black matrix BM and the color filter layers CF 1 , CF 2 , and CF 3 . The planarization layer PL 2 may be made of an inorganic material (e.g., silicon oxide, silicon nitride, silicon oxynitride, or a stack layer having at least two of the above materials), an organic material (e.g., polyimide resin, epoxy resin, or acrylic resin), or a combination of both, but the invention is not limited thereto. In this embodiment, the planarization layer PL 2 may be a single-layer structure, but the invention is not limited thereto. In other embodiments, the planarization layer PL 2 may be a multi-layer structure. In other embodiments, the planarization layer PL 2 may be located between the black matrix BM and the color filter layer.

The display medium layer 140 is disposed between the first substrate 100 and the second substrate 200 , and the display medium layer 140 is disposed between the third electrode CM 2 and the planarization layer PL 2 . In this embodiment, the display medium layer 140 is a liquid crystal layer, and the liquid crystal layer includes a plurality of liquid crystal molecules. The liquid crystal molecules may be positive liquid crystal molecules, negative liquid crystal molecules, or other suitable liquid crystal molecules. Nevertheless, the invention is not limited thereto. In other embodiments, the display medium layer 140 may be other non-self-luminous element (e.g., an electrophoresis element, an electrowetting element, or other suitable elements). In other embodiments, the display medium layer 140 may be a self-luminous element (e.g., a light-emitting diode or other suitable elements).

In this embodiment, as two neighboring color filter layers are correspondingly disposed in one single second opening O 2 of the black matrix BM, a breakthrough regarding limitation of a minimum size of the second opening O 2 can be made. In addition, a portion of the second data line DL 2 exposed by the second opening O 2 may be shielded by the overlapped structure OS. Besides, an electric field at the second body portion 120 of the third electrode CM 2 may affect tilting of the liquid crystal molecules, and a vertical dark line may thus be generated. The vertical dark line may shield the portion of the second data line DL 2 exposed by the second opening O 2 , and thus, a light leakage may be further prevented.

FIG. 4 is a schematic top view of a display panel according to another embodiment of the invention. It should be noted that the reference numerals and a part of the contents in FIG. 1 are also used to describe FIG. 4 , in which the same reference numerals are used to represent identical or similar elements, and thus descriptions of the same technical contents are omitted. Please refer to the descriptions of the previous embodiments for the omitted contents, which will not be repeated hereinafter.

With reference to FIG. 4 , a difference between a display panel 20 illustrated in FIG. 4 and the display panel 10 illustrated in FIG. 1 is that the second openings O 2 of the black matrix BM are arranged in a staggered manner in the first direction E 1 .

In this embodiment, the second openings O 2 of the black matrix BM are arranged in a staggered manner in the first direction E 1 . The second openings O 2 at a first row R 1 and the second openings O 2 at a third row R 3 are aligned in the first direction E 1 , and the second openings O 2 at a second row R 2 and the second openings O 2 at a fourth row R 4 are aligned in the first direction E 1 . The overlapped structures OS located at two neighboring rows in the second openings O 2 are arranged in a staggered manner.

In this embodiment, corresponding to the second openings O 2 , a portion of the overlapped structures OS shields a portion of the first data line DL 1 , and another portion of the overlapped structures OS shields a portion of the second data line DL 2 . The overlapped structures OS and the black matrix BM may shield the scan line SL, the first data line DL 1 , and the second data line DL 2 together.

In this embodiment, given that the second openings O 2 of the black matrix BM are arranged in a staggered manner in the first direction E 1 , color dot shifts generated by the overlapped structure OS or vertical traces generated by non-uniformity of images in display may be reduced. For instance, when the display panel 20 is adopted to display images, the overlapped structures OS located at two neighboring rows (e.g., the first row R 1 and the second row R 2 ) in the second openings O 2 are not located on the same straight line. Hence, uneven brightness distribution of vertical images generated by the overlapped structures OS may be improved, and that the uniformity of images in display of the display panel 20 is enhanced.

In view of the foregoing, in at least one embodiment of the invention, two color filter layers are designed to be disposed in one second opening of the black matrix, and thereby a breakthrough regarding the limitation of the minimum size of the second openings can be made, size of pixels is reduced and a higher resolution is provided. In addition, a portion of the second data line which is not covered by the black matrix is shielded by the overlapped structure formed by two neighboring color filter layers and the second body portion of the third electrode together, and thereby a light leakage is further prevented.

It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure covers modifications and variations provided that they fall within the scope of the following claims and their equivalents.