Display device

Abstract

To provide a display device that can cause high-definition pictures to be displayed even when manufactured using an ink jet device.SOLUTION: A display device comprises: a substrate; and a plurality of pixels formed on a principal surface of the substrate. Each of the pixels includes a plurality of sub-pixels. At least one of the sub-pixels is formed in a long shape having a length in a first direction in a plane view that is shorter than a length in a second direction orthogonal to the first direction. At least one of the sub-pixels coloring different in color from the at least one sub-pixel is formed into a long shape in which a length in the second direction in the plane view is shorter than that in the first direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a display device. [Background technology]

[0002] In order to increase the display area, improve quality, and reduce costs, it is desirable to replace the semiconductor manufacturing process with a printing process for the manufacturing method of display devices. Examples of display devices whose manufacturing method can be replaced with a printing process include organic electroluminescence (EL) display devices and quantum dot display devices.

[0003] For example, an organic EL display device usually has a functional layer containing an organic functional material disposed between an anode and a cathode. Depending on the function of the organic functional material, organic devices such as semiconductor elements (transistors), light-emitting elements, and liquid crystal elements can be obtained. The semiconductor element contains an organic semiconductor material that connects a source electrode and a drain electrode disposed on a substrate surface, for example. The organic EL element has a light-emitting layer containing an organic EL material laminated on an anode electrode disposed on a substrate, for example, and the light-emitting layer is further sandwiched between cathode electrodes.

[0004] In order to pattern a functional material on an electrode, a barrier (i.e., a bank) is formed surrounding the electrode surface, and a composition containing the functional material is printed in the area defined by the bank. The material of the bank may be a resin. When printing an ink containing a functional material in an area including the electrode surface defined by the bank, it is generally preferable that the wettability of the area to be printed (including the electrode surface) is high, and that the wettability of the upper surface of the bank is low. This is to prevent the ink from leaking out to areas other than the intended area. It is generally known that fluorine components reduce the energy of the surface of a material and reduce wettability. Therefore, in order to form a bank with a low wettability upper surface, a technique is known in which the bank surface is plasma-treated using a fluorocarbon gas (see, for example, Patent Document 1).

[0005] On the other hand, in recent years, the relatively low cost of producing display devices using printing methods has led to demand for their application to small, high-definition devices such as smartphones. In order to improve the definition of display devices, a method has been adopted in which the number of highly visible green subpixels is twice as many as the number of red and blue subpixels in the arrangement of RGB (red, green, blue) subpixels. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2005-52835 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the above method of arranging twice as many green subpixels as red and blue subpixels, for example, in the case of a 300 ppi display device, a square (pixel) of 85 μm in length and width contains a total of four subpixels. It was difficult to land ink of each color on four subpixels in such a small pixel using an inkjet device without mixing the inks.

[0008] In view of the above circumstances, an object of the present disclosure is to provide a display device capable of displaying high-definition images even when manufactured using an inkjet device. [Means for solving the problem]

[0009] The display device of the present disclosure comprises a substrate and a plurality of pixels formed on a main surface of the substrate, the pixels comprising a plurality of sub-pixels, at least one of the sub-pixels being formed in an elongated shape whose length in a first direction in a planar view is shorter than its length in a second direction perpendicular to the first direction, and at least one of the sub-pixels, which emits a color different from that of the at least one of the sub-pixels, being formed in an elongated shape whose length in the second direction in a planar view is shorter than its length in the first direction. Effect of the Invention

[0010] According to the display device of the present disclosure, even when manufactured using an inkjet device, it is possible to display high-definition images. [Brief description of the drawings]

[0011] [Figure 1] 1 is a plan view of a display device according to a first embodiment of the present disclosure; [Figure 2A] 1 is a plan view of a display device according to a second embodiment of the present disclosure; [Figure 2B] FIG. 11 is a plan view of a display device according to a first modified example of the second embodiment of the present disclosure. [Figure 2C] FIG. 11 is a plan view of a display device according to a second modified example of the second embodiment of the present disclosure. [Diagram 3] 11 is a plan view of a display device according to a third embodiment of the present disclosure; [Figure 4] FIG. 13 is a plan view of a display device according to a fourth embodiment of the present disclosure. [Diagram 5] FIG. 13 is a plan view of a display device according to a fifth embodiment of the present disclosure. [Figure 6] FIG. 13 is a plan view of a display device according to a sixth embodiment of the present disclosure. [Figure 7] FIG. 13 is a plan view of a display device according to a seventh embodiment of the present disclosure. [Figure 8] FIG. 13 is a plan view of a display device according to an eighth embodiment of the present disclosure. [Figure 9]FIG. 13 is a plan view of a display device according to a ninth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present disclosure will be described. Note that the configurations of the following first to ninth embodiments can be combined within an applicable range.

[0013] [First embodiment] First, a first embodiment of the present disclosure will be described. Fig. 1 is a plan view of a display device according to the first embodiment of the present disclosure.

[0014] 1, a plurality of pixels 102 are arranged in a matrix on a substrate 101 of a display device 100. The pixels 102 are the smallest units that make up an image, and are also called picture elements. The pixels 102 include sub-pixels 103 of each color.

[0015] The subpixels 103 are recesses partitioned by banks 111. For example, a red subpixel 104 is formed by injecting an ink of a red light-emitting material into the subpixel 103. Similarly, a green subpixel 105 and a blue subpixel 106 are formed by injecting ink of a green light-emitting material and an blue subpixel 106 into the subpixel 103, respectively. When an electric field is applied, the red subpixel 104, the green subpixel 105 and the blue subpixel 106 emit red, green and blue light, respectively. The color of the pixel 102 is determined by the intensity of the light emitted by the red subpixel 104, the green subpixel 105 and the blue subpixel 106. In order to improve the image quality of the display device 100, a subpixel 103 that emits white or yellow light may be added to the pixel 102.

[0016] In the present disclosure, it is assumed that an inkjet device is used to manufacture the display device 100. Specifically, it is assumed that ink of each color is deposited on each subpixel 103 and the deposited ink is dried to form a functional film. The functional film thus formed has a light-emitting function and a color conversion function.

[0017] The landing position of ink by an inkjet device usually varies by about several μm. The variation in the landing position in the printing direction D1 (first direction) can be corrected by adjusting the ink ejection timing for each nozzle. However, it is difficult to correct the variation in the landing position in the direction (second direction) D2 in which the nozzles are aligned perpendicular to the printing direction D1 (hereinafter, sometimes referred to as the "nozzle alignment direction"). As a method for correcting the variation in the landing position in the nozzle alignment direction D2, a method of ejecting ink from each nozzle after shifting the stage on which the substrate 101 is placed in the nozzle alignment direction D2 is considered, but this is not practical because it requires a long printing time. The present disclosure is effective in the production of a display device 100 by an inkjet device having such characteristics.

[0018] For example, if the variation in landing position in the printing direction D1 is ±10 μm and the variation in landing position in the nozzle arrangement direction D2 is ±20 μm, the range where the ink lands will be an elongated shape with the length in the printing direction D1 shorter than the length in the nozzle arrangement direction D2. Therefore, by making the shape of the subpixel 103 elongated with the length in the printing direction D1 shorter than the length in the nozzle arrangement direction D2, it is possible to prevent the ink from landing outside the subpixel 103. In the first embodiment, the shape of each subpixel 103 in a plan view is formed as an ellipse defined by a minor axis parallel to the printing direction D1 and a major axis parallel to the nozzle arrangement direction D2. Also, the shape of each subpixel 103 is formed as an ellipse with a length L1 in the printing direction D1 (hereinafter sometimes referred to as the "printing direction length") of 20 μm or more and a length L2 in the nozzle arrangement direction D2 (hereinafter sometimes referred to as the "nozzle arrangement direction length") of 40 μm or more.

[0019] The ratio of the length L1 in the printing direction to the length L2 in the nozzle arrangement direction, which defines the elongated shape of each subpixel 103, can be changed depending on the ejection accuracy of the inkjet device and the landing position correction function in the printing direction D1. In inkjet devices, the accuracy of correcting the landing position in the printing direction D1 is generally more than twice as accurate as the ink ejection accuracy. For this reason, it is desirable to design the length L1 in the printing direction of the subpixel 103 to be 0.5 times or less (half or less) the length L2 in the nozzle arrangement direction.

[0020] [Second embodiment] Next, a second embodiment of the present disclosure will be described. Fig. 2A is a plan view of a display device according to the second embodiment of the present disclosure. Fig. 2B is a plan view of a display device according to a first modified example of the second embodiment of the present disclosure. Fig. 2C is a plan view of a display device according to a second modified example of the second embodiment of the present disclosure.

[0021] 2A, a plurality of pixels 202 are arranged in a matrix on a substrate 201 of a display device 200. Each pixel 202 includes sub-pixels 203 of each color.

[0022] The subpixels 203 include a red subpixel 204, a green subpixel 205, and a blue subpixel 206. The green subpixel 205 is formed in an elliptical shape in a plan view, similar to the green subpixel 105 of the first embodiment. The red subpixel 204 and the green subpixel 205 are formed in a rectangular shape in a plan view. The areas of the red subpixel 204 and the blue subpixel 206 in a plan view are larger than the area of ​​the green subpixel 205 in a plan view. The outer shapes of the red subpixel 204 and the blue subpixel 206 in a plan view are larger than the outer shape of the green subpixel 205 in a plan view.

[0023] Here, since green has a higher visibility than red and blue, the visibility of green, red, and blue can be made substantially the same even if the area of ​​the green subpixel 205 is made smaller than the areas of the red subpixel 204 and blue subpixel 206. However, if the area of ​​the green subpixel 205 is made smaller than the areas of the red subpixel 204 and blue subpixel 206, it becomes more difficult to cause ink from an inkjet device to land on the green subpixel 205 compared to the red subpixel 204 and blue subpixel 206, and the possibility that ink will land outside the green subpixel 205 increases. Thus, as in the second embodiment, forming the shape of the green subpixel 205 in a plan view into an ellipse defined by a minor axis parallel to the printing direction D1 and a major axis parallel to the nozzle arrangement direction D2 is effective for causing ink to land on the green subpixel 205.

[0024] On the other hand, to increase the luminance of red and blue more than that of green, the areas of the red subpixel 204 and the blue subpixel 206 need to be larger than that of the green subpixel 205. If all the subpixels 203 are formed in an ellipse defined by a minor axis parallel to the printing direction D1, the subpixels 203 cannot be arranged at high density on the substrate 201 having a limited area. Therefore, by making the red subpixels 204 and the blue subpixels 206 quadrangular in plan view as in the second embodiment, the subpixels 203 can be arranged at high density.

[0025] However, it is preferable that the shapes of all subpixels 203 in a plan view are shapes that include required landing areas 207. Required landing areas 207 are the minimum areas necessary for ink to land without missing subpixels 203, when taking into consideration variations in the landing positions of ink ejected from an inkjet device. If the shapes of subpixels 203 in a plan view are made to not include required landing areas 207, defects such as ink not landing on subpixels 203 will frequently occur.

[0026] According to the second embodiment as described above, it is possible to provide the display device 200 that can ensure the necessary luminance while achieving high definition.

[0027] If the planar shape of all the subpixels 203 includes the required landing area 207, all the subpixels 203 may be formed in the shapes shown in FIG. 2B and FIG. 2C. All the subpixels 203 can be designed taking into consideration the brightness and material properties required for each color, the difficulty of ink landing at an appropriate position by an inkjet device, and the like. The configuration of FIG. 2B is effective when it is desired to make the red subpixel 204 and the blue subpixel 206 sufficiently large relative to the green subpixel 205, which is the smallest subpixel 203. In the configuration of FIG. 2C, the blue subpixel 206 is made larger relative to the green subpixel 205 and the red subpixel 204. The configuration of FIG. 2C is effective when the emission intensity of blue is lower than that of other colors due to the difficulty of developing blue materials or other reasons.

[0028] [Third embodiment] Next, a third embodiment of the present disclosure will be described. Fig. 3 is a plan view of a display device according to the third embodiment of the present disclosure.

[0029] 3, a plurality of pixels 302 are arranged in a matrix on a substrate 301 of a display device 300. Each pixel 302 includes sub-pixels 303 of each color.

[0030] The green subpixel 305 has higher visibility than the other colors and requires the smallest luminance, so in order to improve the likelihood of landing, it is formed in an elliptical shape in a plan view similar to the green subpixel 105 of the first embodiment. The green subpixel 305 is composed of only a landing region 305A. The red subpixel 304 has a landing region 304A and an ink inflow region 304B. The blue subpixel 306 has a landing region 306A and an ink inflow region 306B.

[0031] The landing areas 304A, 305A, and 306A are areas for landing the ink discharged from the inkjet device. The landing areas 304A, 305A, and 306A are formed in an elliptical shape in plan view, defined by a minor axis parallel to the printing direction D1 and a major axis parallel to the nozzle arrangement direction D2. The landing areas 304A, 305A, and 306A are preferably shaped in plan view to include the landing required area 207. The landing required area 207 is determined depending on the landing accuracy of each color ink in the inkjet device. The landing required area 207 can have a length in the printing direction D1 of, for example, 1 μm to 30 μm, and a length in the nozzle arrangement direction D2 of, for example, 10 μm to 50 μm. However, the length of the landing required area 207 can be set outside the above range depending on the landing accuracy of each color ink.

[0032] The ink inflow areas 304B and 306B are areas for allowing the ink that has landed on the landing areas 304A and 306A to flow in. The ink inflow areas 304B and 306B are formed in a shape such as a rectangle or trapezoid with arc-shaped corners in a plan view.

[0033] Ink is ejected from the inkjet device toward landing regions 304A, 305A, and 306A of subpixel 303. In red subpixel 304 and blue subpixel 306, the ink that has landed in landing regions 304A and 306A spreads toward ink inflow regions 304B and 306B, forming a functional film layer. Landing regions 304A and 306A on which functional films are formed by ink and ink inflow regions 304B and 306B function together as one subpixel 303. Note that since ink inflow regions 304B and 306B are basically not involved in the landing of ink, they can be designed to any size without being restricted by the size of required landing region 207.

[0034] According to the third embodiment described above, it is possible to improve the likelihood of landing, improve the degree of freedom in designing the area of ​​the sub-pixels 303, and achieve high-density arrangement. Furthermore, even in the case of a print-type display device 300 that requires a wide shape in the nozzle arrangement direction D2 for ink landing, high definition can be achieved.

[0035] [Fourth embodiment] Next, a fourth embodiment of the present disclosure will be described. Fig. 4 is a plan view of a display device according to the fourth embodiment of the present disclosure. Hereinafter, mixing of ink into subpixels of other colors is referred to as "color mixing." In the fourth embodiment, a display device that can prevent color mixing while realizing high definition will be described.

[0036] 4, a plurality of pixels 402 are arranged in a matrix on a substrate 401 of a display device 400. Each pixel 402 includes sub-pixels 403 of each color.

[0037] The green subpixel 405 is composed only of a landing region 405A. The red subpixel 404 has a landing region 404A and an ink inflow region 404B. The blue subpixel 406 has a landing region 406A and an ink inflow region 406B.

[0038] The shape of landing regions 404A, 405A, 406A in a plan view is preferably an ellipse defined by a minor axis parallel to printing direction D1 and a major axis parallel to nozzle arrangement direction D2, and is a shape that encompasses required landing region 207. Landing regions 404A, 405A, 406A have higher wettability than bank 411 surrounding subpixel 403. Landing regions 404A, 405A, 406A include light emitting regions 404C, 405C, 406C and non-light emitting regions 404D, 405D, 406D. Light emitting regions 404C, 405C, 406C are located in the center of landing regions 404A, 405A, 406A, and are regions that emit light when an electric field is applied. Since light emitting regions 404C, 405C, and 406C are not restricted in size by the required landing region 207, they are formed, for example, in a circular or elliptical shape in a planar view. Non-light emitting regions 404D, 405D, and 406D are formed in a shape surrounding light emitting regions 404C, 405C, and 406C. The wettability of light emitting regions 404C, 405C, and 406C is equal to or greater than the wettability of non-light emitting regions 404D, 405D, and 406D. In other words, the wettability of each region satisfies the following relationship. Bank < Non-light emitting area < Light emitting area

[0039] The inkjet device ejects ink toward landing regions 404A, 405A, and 406A of subpixel 403. For example, as shown in Fig. 4, when ink 420 misses light-emitting region 405C of green subpixel 405 and lands in a region extending from non-light-emitting region 405D to bank 411, the landing ink 420 is first drawn into landing region 405A due to the high wettability of landing region 405A. Then, ink 420 drawn into landing region 405A further flows into light-emitting region 405C, which has a higher wettability than non-light-emitting region 405D, and reaches the center of light-emitting region 405C. Depending on the volume of the ink 420 that has landed, ink may be present only in the light-emitting areas 404C, 405C, and 406C, or ink may be present in both the light-emitting areas 404C, 405C, and 406C and the non-light-emitting areas 404D, 405D, and 406D. However, because the non-light-emitting areas 404D, 405D, and 406D do not contribute to light emission, there is no problem with quality in either case.

[0040] Furthermore, ink inflow regions 404B, 406B exist in the red subpixel 404 and the blue subpixel 406. By making the wettability of the ink inflow regions 404B, 406B equal to that of the light emitting regions 404C, 406C or slightly higher than that of the non-light emitting regions 404D, 406D, ink that arrives at the light emitting regions 404C, 406C can be made to wet and spread into the light emitting regions 404C, 406C and the ink inflow regions 404B, 406B.

[0041] According to the fourth embodiment as described above, for luminance design, the sizes of red subpixel 404 and blue subpixel 406 are made sufficiently larger than green subpixel 405, and when high definition is desired, light emitting area 405C can be made small while ensuring landing area 405A of green subpixel 405. Furthermore, when the ink landing accuracy of red subpixel 404 or blue subpixel 406 is low, landing defects can be reduced.

[0042] [Fifth embodiment] Next, a fifth embodiment of the present disclosure will be described. Fig. 5 is a plan view of a display device according to the fifth embodiment of the present disclosure.

[0043] 5, a plurality of pixels 502 are arranged in a matrix on a substrate 501 of a display device 500. Each pixel 502 includes sub-pixels 503 of each color.

[0044] Of the subpixels 503 of each color, the green subpixel 505 is formed by printing in the first printing direction D11. When forming the green subpixel 505, the landing accuracy in the first nozzle arrangement direction D21 is worse than that in the first printing direction D11, so the landing required region 507A becomes an ellipse defined by a minor axis parallel to the first printing direction D11 and a major axis parallel to the first nozzle arrangement direction D21. In accordance with the shape of this landing required region 507A, the green subpixel 505 is formed in an ellipse defined by a minor axis parallel to the first printing direction D11 and a major axis parallel to the first nozzle arrangement direction D21 in a plan view.

[0045] On the other hand, the red subpixels 504 and the blue subpixels 506 are formed by printing in a second printing direction D12 (second direction) that is perpendicular to the first printing direction D11. When forming the red subpixels 504 and the blue subpixels 506, the landing accuracy in the second nozzle arrangement direction D22 (first direction) is worse than that in the second printing direction D12, so the landing required region 507B becomes an ellipse defined by a minor axis parallel to the second printing direction D12 and a major axis parallel to the second nozzle arrangement direction D22. To match the shape of this landing required region 507B, the red subpixels 504 and the blue subpixels 506 are formed as rectangles whose long sides are parallel to the second nozzle arrangement direction D22 in a plan view.

[0046] Examples of methods for changing the printing direction to the first printing direction D11 or the second printing direction D12 include changing the stage movement direction and the angle of the nozzle head, rotating the stage by 90 degrees, or using multiple inkjet devices.

[0047] According to the fifth embodiment as described above, the degree of freedom in the layout of the sub-pixels 503 is improved, and higher definition can be achieved.

[0048] [Sixth embodiment] Next, a sixth embodiment of the present disclosure will be described below. Fig. 6 is a plan view of a display device according to the sixth embodiment of the present disclosure.

[0049] 6, a plurality of pixels 602 are arranged in a matrix on a substrate 601 of a display device 600. Each pixel 602 includes sub-pixels 603 of each color.

[0050] In order to make the area of ​​the green subpixel 605 as small as possible and ensure the stability of ink landing, the green subpixel 605 is formed in an elliptical shape in a planar view similar to the green subpixel 105 of the first embodiment, and is an elliptical shape that encompasses the required landing area 207.

[0051] The red subpixel 604 and the blue subpixel 606 are formed, for example, in a trapezoid whose upper base is parallel to the length L2 in the nozzle arrangement direction in a plan view. The red subpixel 604 and the blue subpixel 606 are formed in a shape that includes the landing required region 207 on the base side that is longer than the center in the height direction of the trapezoid. The red subpixel 604 and the blue subpixel 606 are arranged alternately along the printing direction D1 and the length L2 in the nozzle arrangement direction. The red subpixel 604 is formed so that the shorter base side is located further forward in the printing direction D1 (upper side in FIG. 6) than the longer base side. The blue subpixel 606 is formed so that the shorter base side is located further backward in the printing direction D1 (lower side in FIG. 6) than the longer base side.

[0052] The green subpixels 605 aligned in the long side direction of the ellipse (nozzle arrangement direction D2) are connected to each other at the center of the short side direction via an ink flow path 605E. The red subpixels 604 aligned in the direction parallel to the base of the trapezoid (nozzle arrangement direction D2) are connected to each other at the long side of the base via an ink flow path 604E. The blue subpixels 606 aligned in the direction parallel to the base of the trapezoid are connected to each other at the long side of the base via an ink flow path 606E. The ink flow paths 604E, 605E, and 606E have a function of causing a part of the ink that has landed on the subpixel 603 located at one end side of the ink flow paths 604E, 605E, and 606E to flow into the subpixel 603 located at the other end side. The ink flow paths 604E, 605E, and 606E may be formed in a curved shape.

[0053] According to the sixth embodiment as described above, when the volumes of ink that land on adjacent subpixels 603 are different, ink is caused to flow from the subpixel 603 with a larger ink volume to the subpixel 603 with a smaller ink volume via the ink flow paths 604E, 605E, and 606E, thereby suppressing the variation in the ink volumes of the adjacent subpixels 603. Even if a nozzle that ejects ink onto a specific subpixel 603 becomes clogged, a portion of the ink that landed on the subpixel 603 adjacent to the specific subpixel 603 is caused to flow into the specific subpixel 603 via the ink flow paths 604E, 605E, and 606E, thereby suppressing the variation in the ink volumes of the adjacent subpixels 603. Therefore, the brightness difference between the subpixels 603 can be reduced.

[0054] [Seventh embodiment] Next, a seventh embodiment of the present disclosure will be described. Fig. 7 is a plan view of a display device according to the seventh embodiment of the present disclosure.

[0055] 7, a plurality of pixels 702 are arranged in a matrix on a substrate 701 of a display device 700. Each pixel 702 includes sub-pixels 703 of each color.

[0056] The red subpixels 704 and blue subpixels 706 are alternately arranged along the printing direction D1 and the nozzle arrangement direction length L2. The red subpixels 704 aligned in a direction tilted at 45 degrees to the printing direction D1 are connected to each other via ink flow paths 704E. The blue subpixels 706 aligned in a direction tilted at 45 degrees to the printing direction D1 are connected to each other via ink flow paths 706E.

[0057] The green subpixel 705 is disposed in an area surrounded by a pair of red subpixels 704 and a pair of blue subpixels 706. Each green subpixel 705 is connected via an ink flow path 705E to the adjacent green subpixel 705 on the front side of the printing direction D1 (the upper side in FIG. 7) and to the adjacent green subpixel 705 on one side of the nozzle alignment direction D2 (the right side in FIG. 7). The ink flow path 705E extending in the printing direction D1 extends in a direction approximately parallel to the printing direction D1. The ink flow path 705E extending in the nozzle alignment direction D2 extends in a direction inclined at about 30° with respect to the nozzle alignment direction D2. In other words, the ink flow paths 704E, 706E connecting the red subpixels 704 or the blue subpixels 706 that emit red or blue light, which are an example of a first color, extend in an oblique direction relative to the extension direction of the ink flow path 705E connecting the green subpixels 705 that emit green light, which is an example of a second color. The ink flow paths 704E, 705E, 706E may be formed in a curved shape.

[0058] According to the seventh embodiment described above, even if variations in the ink ejection volume occur due to vibrations of the inkjet device or pulsations of the pump that supplies ink to the nozzle head, ink can be caused to flow in and out via the ink flow paths 704E, 705E, and 706E between subpixels 703 of the same color that have different ejection timings. Therefore, it is possible to suppress variations in the ink volume of the subpixels 703 connected by the ink flow paths 704E, 705E, and 706E, and it is possible to reduce the brightness difference between the subpixels 703.

[0059] [Eighth embodiment] Next, an eighth embodiment of the present disclosure will be described. Fig. 8 is a plan view of a display device according to the eighth embodiment of the present disclosure.

[0060] 8, a plurality of pixels 802 are arranged in a matrix on a substrate 801 of a display device 800. Each pixel 802 includes sub-pixels 803 of each color.

[0061] Taking into consideration the ink landing accuracy, the red subpixel 804 and the green subpixel 805 are formed in an elliptical shape in a plan view, similar to the green subpixel 105 of the first embodiment. An annular bank 811 is formed around each of the red subpixel 804 and the green subpixel 805. The bank 811 has the function of insulating adjacent subpixels 803 and the function of preventing color mixing.

[0062] The blue subpixel 806 is formed by the area on the substrate 801 other than the red subpixel 804 , the green subpixel 805 , and the bank 811 .

[0063] According to the eighth embodiment described above, it is possible to apply the blue ink in large droplets using a nozzle having an ejection hole of, for example, 30 μm or more, since there is no problem even if the landing accuracy of the blue ink is lower than that of the red and green inks in terms of the size of the subpixels 803. In addition, the area occupied by the bank 811 per unit area can be minimized, and high definition can be achieved.

[0064] In the eighth embodiment, the blue subpixel 806 is larger than the subpixels 803 of other colors, but the subpixels 803 of any color may be larger than the subpixels 803 of other colors for reasons such as low brightness, short life span of the luminescent material, low sensitivity of the human eye, low manufacturing cost of the material, etc. In addition, in FIG. 8, the blue subpixels 806 may be divided by connecting adjacent banks 811 with another bank.

[0065] [Ninth embodiment] Next, a ninth embodiment of the present disclosure will be described. Fig. 9 is a plan view of a display device according to the ninth embodiment of the present disclosure.

[0066] 9, a plurality of pixels 902 are arranged in a matrix on a substrate 901 of a display device 900. Each pixel 902 includes sub-pixels 903 of each color.

[0067] The green subpixel 905 has a smaller area than the red subpixel 904 and the blue subpixel 906. The green subpixel 905 includes a landing area 905A and a non-landing area 905B. The landing area 905A is an area where ink lands and emits light when an electric field is applied. The landing area 905A is preferably formed in an elliptical shape defined by a minor axis parallel to the printing direction D1 and a major axis parallel to the nozzle arrangement direction D2, and has a shape that includes the landing required area 207. The non-landing area 905B is an area where ink does not land and emits light when an electric field is applied. For this reason, the shape of the non-landing area 905B can be determined without being restricted by the landing required area 207. In the ninth embodiment, the non-landing area 905B is formed in a circular shape. The landing area 905A and the non-landing area 905B are connected by an ink flow path 905E.

[0068] A portion of the ink that has landed in landing area 905A flows into non-landing area 905B via ink flow path 905E. This inflow of ink can cause landing area 905A and non-landing area 905B to emit light. There is a concern that a difference in the amount of green light emitted will occur due to the difference in area between landing area 905A and non-landing area 905B, but this problem can be resolved by controlling the strength of the electric field applied to landing area 905A and non-landing area 905B.

[0069] According to the ninth embodiment described above, in addition to the impact area 905A, the non-impact area 905B that is not restricted by the required impact area 207 can also be illuminated, thereby enabling the nozzle arrangement direction D2 in particular to be made smaller while also achieving higher definition.

[0070] [Modification of the embodiment] Needless to say, the present disclosure is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present disclosure.

[0071] For example, in the fourth embodiment, the wettability of a first width region of bank 411 surrounding landing regions 404A, 405A, and 406A may be made higher than the wettability of a second width region of bank 411 surrounding ink inflow regions 404B and 406B. Here, the first width and the second width may be the same or different. With this configuration, for example, when part of red ink ejected aiming at landing region 404A of red subpixel 404 lands in a region between landing region 404A and ink inflow region 406B of green subpixel 406, the part of the ink can be drawn toward landing region 404A, which has a higher wettability.

[0072] For example, in the sixth and seventh embodiments, among the multiple subpixels 603, 703 that emit light of the same color, at least one subpixel 603, 703 may not be connected to the ink flow paths 604E, 605E, 606E, 704E, 705E, 706E. For example, among the multiple red subpixels 604, at least one red subpixel 604 may not be connected to the other red subpixels 604 via the ink flow path 604E.

[0073] For example, in the sixth and seventh embodiments, a plurality of sub-pixels 603, 703 that emit light of a predetermined color may be connected in a matrix via ink flow paths 604E, 605E, 606E, 704E, 705E, 706E. For example, four green sub-pixels 705 may be connected in a matrix via an ink flow path 705E.

[0074] For example, in the first embodiment, among the multiple subpixels 103 emitting light of the same color, at least one subpixel 103 may have a different shape from the other subpixels 103. For example, among the multiple red subpixels 104, at least one red subpixel 104 may have a different shape from the other red subpixels 104. Similar modifications may also be applied to the second to ninth embodiments.

[0075] For example, in the first embodiment, adjacent sub-pixels 103 that emit light of the same color may have different shapes. For example, adjacent red sub-pixels 104 may have different shapes. Similar modifications may also be applied to the second to ninth embodiments.

[0076] For example, in the first embodiment, the area of ​​at least one of the subpixels 103 emitting light of the same color may be different from the area of ​​the other subpixels 103. Furthermore, the areas of adjacent subpixels 103 emitting light of the same color may be different from each other. For example, the area of ​​at least one of the multiple red subpixels 104 may be different from the area of ​​the other red subpixels 104, or the areas of adjacent red subpixels 104 may be different from each other. Furthermore, similar modifications may be applied to the second to ninth embodiments.

[0077] For example, in the first embodiment, an ellipse is given as an example of the elongated shape of the sub-pixel 103, but the shape may be any shape in which the length L1 in the printing direction is shorter than the length L2 in the nozzle arrangement direction, such as a rectangle or a diamond. Similar modifications may also be applied to the second to ninth embodiments. [Industrial Applicability]

[0078] INDUSTRIAL APPLICABILITY The display device according to the present disclosure is extremely useful and has high industrial applicability since it is possible to achieve the highest possible resolution by using a printing method. [Explanation of symbols]

[0079] 100,200,300,400,500,600,700,800,900 display devices 101,201,301,401,501,601,701,801,901 Board 102,202,302,402,502,602,702,802,902 pixels 103,203,303,403,503,603,703,803,903 subpixels 104,204,304,404,504,604,704,804,904 Red subpixel 105,205,305,405,505,605,705,805,905 Green subpixel 106,206,306,406,506,606,706,806,906 Blue subpixels 111,411,811 Bank 207,507A,507B Required landing area 304A, 305A, 306A, 404A, 405A, 406A, 905A Ink landing area 304B, 306B, 404B, 406B Ink inflow area 404C, 405C, 406C Light-emitting area 404D, 405D, 406D Non-luminous area 420 Ink 604E, 605E, 606E, 704E, 705E, 706E, 905E Ink flow path 905B Non-Impact Area D1 Print direction D11 First printing direction D12 Second Printing Direction D2 Nozzle arrangement direction D21 1st nozzle arrangement direction D22 Second nozzle arrangement direction

Claims

1. A substrate; a plurality of pixels formed on the substrate; The pixel comprises a plurality of sub-pixels; At least one of the sub-pixels is formed in an elongated shape whose length in a first direction in a plan view is shorter than its length in a second direction perpendicular to the first direction, A display device, wherein at least one of the subpixels that emits a color different from that of the at least one subpixel is formed in an elongated shape whose length in the second direction in a planar view is shorter than its length in the first direction.

2. 2. The display device of claim 1, wherein the length of the at least one subpixel in the first direction is less than or equal to 0.5 times its length in the second direction.

3. The display device according to claim 1 , wherein the subpixel having the smallest area among the plurality of subpixels is formed in the elongated shape.

4. The display device according to claim 3 , wherein an outer shape in a plan view of the subpixel whose area is not the smallest among the plurality of subpixels is larger than an outer shape in a plan view of the subpixel whose area is the smallest.

5. The display device according to claim 4 , wherein the subpixel having a non-smallest area is formed in an elongated shape having a length in the first direction longer than a length in the second direction.

6. The at least one sub-pixel comprises: a landing area on which ink is landed, the landing area being formed in an elongated shape with a length in the first direction being shorter than a length in the second direction; The display device according to claim 1 , further comprising: an ink inflow area connected to the landing area and configured to receive a portion of the ink that has landed on the landing area.

7. The display device according to claim 6 , wherein the wettability of the banks that divide the sub-pixels is lower than the wettability of the landing areas.

8. A portion of the subpixel constitutes a light-emitting region that emits light when an electric field is applied thereto, The display device according to claim 6 or 7, wherein the wettability of the light-emitting region is higher than the wettability of a region other than the light-emitting region of the subpixel.

9. 9. The display device according to claim 1, further comprising an ink flow path configured to connect the subpixels that emit light of the same color and to cause a portion of ink that has landed on one subpixel to flow into the other subpixel.

10. 10. The display device according to claim 9, wherein an ink flow path connecting the sub-pixels that emit light of a first color extends in a direction oblique to a direction in which an ink flow path connecting the sub-pixels that emit light of a second color extends.

11. 11. The display device according to claim 9, wherein at least one subpixel among the plurality of subpixels that emit light of the same color is not connected to the ink flow path.

12. The display device according to claim 9 , wherein the sub-pixels emitting light of one predetermined color are connected in a matrix form via the ink flow path.

13. 13. The display device according to claim 1, wherein the shape of at least one of the sub-pixels emitting the same color is different from the shapes of the other sub-pixels.

14. 14. The display device of claim 13, wherein adjacent subpixels that emit the same color are different in shape.

15. 15. The display device according to claim 1, wherein an area of ​​at least one of the sub-pixels emitting the same color is different from an area of ​​the other sub-pixels.

16. 16. The display device of claim 15, wherein adjacent subpixels that emit the same color have different areas.

Images