Display device manufacturing method

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] To achieve larger display areas, higher quality, and lower costs, it is desirable to replace the semiconductor manufacturing process with a printing process for display device manufacturing. Examples of display devices whose manufacturing process can be replaced with a printing process include organic EL display devices and quantum dot display devices.

[0003] For example, an organic EL display device typically 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. A semiconductor element, for example, contains an organic semiconductor material that connects a source electrode and a drain electrode disposed on a substrate surface. An organic EL element, for example, has a light-emitting layer containing an organic EL material laminated on an anode electrode disposed on a substrate, 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 area to be printed (including the electrode surface) has high wettability, and that the upper surface of the bank has low wettability. This is to prevent the ink from leaking outside the intended area. Fluorine components are generally known to reduce the energy of a material surface and reduce wettability. Therefore, a technique for plasma treating the bank surface using a fluorocarbon gas is known to form a bank with a low-wettability upper surface (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-resolution devices such as smartphones. To improve the resolution of display devices, one method has been to arrange the highly visible green subpixels in the RGB (red, green, blue) subpixel array in twice the number of red and blue subpixels. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-52835 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) measuring 85 μm in length and width contains a total of four subpixels. It was difficult to land inks of each color on four subpixels in such a small pixel using an inkjet device without mixing them.

[0008] In view of the above circumstances, an object of the present disclosure is to provide a display device that can display 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, each of the pixels comprising a plurality of sub-pixels, at least one of the sub-pixels being formed in an elongated shape such that the length in a first direction in a planar view is shorter than the length in a second direction perpendicular to the first direction, and at least one of the sub-pixels that emits a color different from that of the at least one of the sub-pixels being formed in an elongated shape such that the length in the second direction in a planar view is shorter than the length in the first direction. [Effects 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 explanation 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] 10 is a plan view of a display device according to a second embodiment of the present disclosure; [Figure 2B] FIG. 10 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. 10 is a plan view of a display device according to a second modified example of the second embodiment of the present disclosure. [Figure 3] 10 is a plan view of a display device according to a third embodiment of the present disclosure; [Figure 4] FIG. 10 is a plan view of a display device according to a fourth embodiment of the present disclosure. [Figure 5] FIG. 10 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 INVENTION

[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] As shown in Fig. 1, a plurality of pixels 102 are arranged in a matrix on a substrate 101 of a display device 100. The pixel 102 is the smallest unit that constitutes an image and is also called a picture element. The pixel 102 includes sub-pixels 103 of each color.

[0015] The subpixels 103 are recesses defined by banks 111. For example, red subpixels 104 are formed by injecting ink made of a red luminescent material into the subpixels 103. Similarly, green and blue subpixels 105 and 106 are formed by injecting ink made of a green and blue luminescent material into the subpixels 103, respectively. The red subpixels 104, 105, and 106 emit red, green, and blue light, respectively, when an electric field is applied. The color of the pixel 102 is determined by the intensity of the light emitted by the red subpixels 104, 105, and 106. Note that, to improve the image quality of the display device 100, subpixels 103 that emit 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 produce 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 ink landing position of an inkjet device typically varies by several micrometers. The variation in 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 landing position in the direction D2 (second direction) in which the nozzles are aligned perpendicular to the printing direction D1 (hereinafter, sometimes referred to as the "nozzle alignment direction"). One possible method for correcting the variation in landing position in the nozzle alignment direction D2 is to eject ink from each nozzle after shifting the stage on which the substrate 101 is placed in the nozzle alignment direction D2, but this is not practical because it requires a long printing time. The present disclosure is effective in producing display devices 100 using inkjet devices with 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 in which the ink lands will be elongated, with its length in the printing direction D1 being shorter than its length in the nozzle arrangement direction D2. Therefore, by making the shape of the subpixel 103 elongated, with its length in the printing direction D1 being shorter than its 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. Furthermore, 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 array 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. Inkjet devices generally have an accuracy of correcting the landing position in the printing direction D1 that is at least 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 no more than 0.5 times (no more than half) the length L2 in the nozzle array 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 has an elliptical shape in plan view, similar to the green subpixel 105 of the first embodiment. The red subpixel 204 and the green subpixel 205 have a rectangular shape in plan view. The areas of the red subpixel 204 and the blue subpixel 206 in plan view are larger than the area of ​​the green subpixel 205 in plan view. The outer shapes of the red subpixel 204 and the blue subpixel 206 in plan view are larger than the outer shape of the green subpixel 205 in plan view.

[0023] Here, because green has higher visibility than red and blue, the visibility of green, red, and blue can be made approximately the same even if the area of ​​the green subpixel 205 is smaller than the areas of the red subpixel 204 and the blue subpixel 206. However, if the area of ​​the green subpixel 205 is smaller than the areas of the red subpixel 204 and the blue subpixel 206, it becomes more difficult for ink from an inkjet device to land on the green subpixel 205 than on the red subpixel 204 and the blue subpixel 206, increasing the likelihood that ink will land outside the green subpixel 205. Therefore, as in the second embodiment, forming the green subpixel 205 in a planar view as an ellipse defined by its minor axis parallel to the printing direction D1 and its major axis parallel to the nozzle arrangement direction D2 is effective for landing ink 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 subpixels 204 and blue subpixels 206 need to be larger than that of the green subpixel 205. If all the subpixels 203 were formed in an ellipse defined by a minor axis parallel to the printing direction D1, the subpixels 203 could not be arranged at high density on the limited area of ​​the substrate 201. Therefore, by making the red subpixels 204 and 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 shape of all subpixels 203 in a plan view be a shape that includes the required landing area 207. The required landing area 207 is the minimum area necessary for ink to land without missing the subpixel 203, taking into account variations in the landing position of ink ejected from the inkjet device. If the shape of the subpixels 203 in a plan view is a shape that does not include the required landing area 207, defects such as ink not landing on the subpixel 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 brightness while achieving high definition.

[0027] Note that all subpixels 203 may be formed in the shapes shown in FIGS. 2B and 2C as long as their planar shapes encompass the required landing area 207. All subpixels 203 can be designed taking into account the required brightness and material properties for each color, the difficulty of ink being deposited at the appropriate position by an inkjet device, and other factors. The configuration of FIG. 2B is effective when the red subpixel 204 and blue subpixel 206 are required to be 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 larger than the green subpixel 205 and 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 difficulties in 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 lowest brightness, so to improve landing likelihood, it is formed in an elliptical shape in plan view, similar to the green subpixel 105 of the first embodiment. The green subpixel 305 is composed of only a landing area 305A. The red subpixel 304 has a landing area 304A and an ink inflow area 304B. The blue subpixel 306 has a landing area 306A and an ink inflow area 306B.

[0031] The landing areas 304A, 305A, and 306A are areas where ink ejected from the inkjet device lands. The landing areas 304A, 305A, and 306A are elliptical in plan view, with a minor axis parallel to the printing direction D1 and a major axis parallel to the nozzle alignment direction D2. The landing areas 304A, 305A, and 306A preferably have a shape that encompasses the required landing area 207. The required landing area 207 is determined based on the landing accuracy of each color of ink in the inkjet device. The length of the required landing area 207 in the printing direction D1 can be, for example, between 1 μm and 30 μm, and the length in the nozzle alignment direction D2 can be between 10 μm and 50 μm. However, the length of the required landing area 207 can be set outside the above range depending on the landing accuracy of each color of ink.

[0032] The ink inflow areas 304B and 306B are areas for allowing ink that has landed on the landing areas 304A and 306A to flow in. The ink inflow areas 304B and 306B have a rectangular or trapezoidal shape with arc-shaped corners when viewed from above.

[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, ink that lands 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 a single subpixel 303. Note that because ink inflow regions 304B and 306B are not generally involved in ink landing, 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 ink landing, increase the degree of freedom in designing the area of ​​the subpixels 303, and achieve high-density arrangement. Furthermore, even in 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, the mixing of ink into subpixels of other colors will be referred to as "color mixing." In the fourth embodiment, a display device that can prevent color mixing while achieving 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 of only a landing area 405A. The red subpixel 404 has a landing area 404A and an ink inflow area 404B. The blue subpixel 406 has a landing area 406A and an ink inflow area 406B.

[0038] The planar shape of the landing regions 404A, 405A, and 406A is preferably elliptical, defined by a minor axis parallel to the printing direction D1 and a major axis parallel to the nozzle arrangement direction D2, and encompasses the required landing region 207. The landing regions 404A, 405A, and 406A have higher wettability than the bank 411 surrounding the subpixel 403. The landing regions 404A, 405A, and 406A include luminous regions 404C, 405C, and 406C and non-luminous regions 404D, 405D, and 406D. The luminous regions 404C, 405C, and 406C are located in the centers of the landing regions 404A, 405A, and 406A, and emit light when an electric field is applied. Light-emitting regions 404C, 405C, and 406C are not restricted in size by the required landing region 207, and are therefore formed, for example, in a circular or elliptical shape in plan view. Non-light-emitting regions 404D, 405D, and 406D are formed in a shape that surrounds 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] Ink is ejected from the inkjet device toward landing regions 404A, 405A, and 406A of subpixel 403. For example, as shown in Figure 4, when ink 420 misses light-emitting region 405C of green subpixel 405 and lands in the 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 flows further 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, since 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] Ink inflow regions 404B and 406B are present in the red subpixel 404 and the blue subpixel 406. By making the wettability of the ink inflow regions 404B and 406B equal to that of the light-emitting regions 404C and 406C or slightly higher than that of the non-light-emitting regions 404D and 406D, ink that arrives at the light-emitting regions 404C and 406C can be made to wet and spread into the light-emitting regions 404C and 406C and the ink inflow regions 404B and 406B.

[0041] According to the fourth embodiment described above, for brightness design purposes, the sizes of the red subpixel 404 and the blue subpixel 406 are made sufficiently larger than the green subpixel 405, and when high resolution is desired, it is possible to reduce the light-emitting area 405C while ensuring the landing area 405A of the green subpixel 405. Furthermore, when the ink landing accuracy of the red subpixel 404 or the blue subpixel 406 is low, it is possible to reduce landing defects.

[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 alignment direction D21 is worse than in the first printing direction D11, so the landing required region 507A is elliptical, defined by a minor axis parallel to the first printing direction D11 and a major axis parallel to the first nozzle alignment direction D21. To match the shape of this landing required region 507A, the green subpixel 505 is formed in an elliptical shape, defined by a minor axis parallel to the first printing direction D11 and a major axis parallel to the first nozzle alignment direction D21 in a plan view.

[0045] On the other hand, the red subpixels 504 and 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 blue subpixels 506, the landing accuracy in the second nozzle alignment direction D22 (first direction) is worse than in the second printing direction D12, so the landing required region 507B is elliptical, defined by a minor axis parallel to the second printing direction D12 and a major axis parallel to the second nozzle alignment direction D22. To match the shape of this landing required region 507B, the red subpixels 504 and blue subpixels 506 are formed as rectangles whose long sides are parallel to the second nozzle alignment 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 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. 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 minimize the area of ​​the green subpixel 605 and ensure stable ink landing, the green subpixel 605 is formed in an elliptical shape in plan view, similar to the green subpixel 105 of the first embodiment, and encompasses the required landing area 207.

[0051] The red subpixels 604 and blue subpixels 606 are formed, for example, in a trapezoidal shape with their upper bases parallel to the length L2 in the nozzle alignment direction in a plan view. The red subpixels 604 and blue subpixels 606 are formed in a shape that encompasses the required landing area 207 on the side of the base that is longer than the center of the trapezoid's height. The red subpixels 604 and blue subpixels 606 are arranged alternately along the printing direction D1 and the length L2 in the nozzle alignment direction. The red subpixels 604 are formed so that their shorter base is located further forward in the printing direction D1 (upper side in FIG. 6) than their longer base. The blue subpixels 606 are formed so that their shorter base is located further backward in the printing direction D1 (lower side in FIG. 6) than their longer base.

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

[0053] According to the sixth embodiment 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 the larger ink volume to the subpixel 603 with the smaller ink volume via the ink flow paths 604E, 605E, and 606E, thereby suppressing variations in the ink volumes of the adjacent subpixels 603. Furthermore, even if a nozzle that ejects ink onto a specific subpixel 603 becomes clogged, some 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 variations 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 arranged alternately along the printing direction D1 and the nozzle alignment 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 located 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 in the printing direction D1 (the upper side in FIG. 7) and to the adjacent green subpixel 705 on one side in 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 approximately 30° with respect to the nozzle alignment direction D2. In other words, ink flow paths 704E, 706E connecting red subpixels 704 or blue subpixels 706 that emit red or blue light, respectively, which are an example of a first color, extend obliquely relative to the direction in which ink flow path 705E connecting green subpixels 705 that emit green light, which are an example of a second color, extends. Note that 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 ink ejection volume occur due to vibrations of the inkjet device or pulsation of the pump that supplies ink to the nozzle head, ink can be made 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, variations in ink volume between the subpixels 703 connected by the ink flow paths 704E, 705E, and 706E can be suppressed, and the brightness difference between the subpixels 703 can be reduced.

[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 ink landing accuracy into consideration, the red subpixel 804 and the green subpixel 805 are formed in an elliptical shape in 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, even if the landing accuracy of blue ink is lower than that of red or green ink, it does not matter in terms of the size of the subpixel 803, so the blue ink can be applied in large droplets using a nozzle with an ejection hole of, for example, 30 μm or more. Furthermore, the area occupied by the bank 811 per unit area can be minimized, allowing for higher resolution.

[0064] Although the eighth embodiment illustrates a case in which the blue subpixel 806 is larger than the subpixels 803 of other colors, the size of the subpixel 803 of any color may be larger than the subpixels 803 of other colors for reasons such as low brightness, a short life span of the light-emitting material, low sensitivity of the human eye, or low manufacturing costs of the material. Also, in FIG. 8, the blue subpixel 806 may be divided by connecting adjacent banks 811 with other banks.

[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 elliptical, defined by a minor axis parallel to the printing direction D1 and a major axis parallel to the nozzle arrangement direction D2, and is a shape that encompasses the required landing area 207. The non-landing area 905B is an area where ink does not land and emits light when an electric field is applied. Therefore, the shape of the non-landing area 905B can be determined without being restricted by the required landing area 207. In the ninth embodiment, the non-landing area 905B is circular. The landing area 905A and the non-landing area 905B are connected by an ink flow path 905E.

[0068] Some of the ink that lands in impact area 905A flows into non-impact area 905B via ink flow path 905E. This ink flow causes impact area 905A and non-impact area 905B to emit light. Note that there is a concern that the difference in area between impact area 905A and non-impact area 905B may result in a difference in the amount of green light emitted, but this problem can be resolved by controlling the strength of the electric field applied to impact area 905A and non-impact area 905B.

[0069] According to the ninth embodiment described above, in addition to the impact area 905A, the non-impact area 905B, which is not restricted by the required impact area 207, can also be illuminated, thereby achieving high resolution while also achieving miniaturization in particular in the nozzle arrangement direction D2.

[0070] [Modification of the embodiment] It goes without saying that 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 the bank 411 surrounding the landing regions 404A, 405A, and 406A may be higher than the wettability of a second-width region of the bank 411 surrounding the 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, if part of the red ink ejected targeting the landing region 404A of the red subpixel 404 lands in the region between the landing region 404A and the ink inflow region 406B of the green subpixel 406, the part of the ink can be drawn into the landing region 404A, which has 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 an ink flow path 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 another red subpixel 604 via an 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, and 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 plurality of subpixels 103 that emit light of the same color, the shape of at least one subpixel 103 may be different from the shapes of the other subpixels 103. For example, among the plurality of red subpixels 104, the shape of at least one red subpixel 104 may be different from the shapes of 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 that emit light of the same color may be different from the area of ​​the other subpixels 103. Also, the areas of adjacent subpixels 103 that emit 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. Also, similar modifications may be applied to the second to ninth embodiments.

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

[0078] The display device according to the present disclosure is extremely useful and has high industrial applicability because it can achieve the highest possible resolution 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 subpixels 105,205,305,405,505,605,705,805,905 Green subpixels 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 print direction D2 Nozzle arrangement direction D21 First 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 such that a length in a first direction in a plan view is shorter than a length in a second direction perpendicular to the first direction, a display device manufacturing method, wherein at least one of the sub-pixels that emits a color different from that of the at least one sub-pixel is formed in an elongated shape whose length in the second direction in plan view is shorter than its length in the first direction, a first step of forming the at least one sub-pixel by printing along the first direction using an inkjet device; a second step of forming the subpixel that emits a color different from the at least one subpixel by performing printing along the second direction with the inkjet device. A method for manufacturing a display device.

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

3. The method of manufacturing a 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. 4. The method of manufacturing a display device according to claim 3, wherein the outer shape of the subpixel having the non-smallest area in plan view among the plurality of subpixels is larger than the outer shape of the subpixel having the smallest area in plan view.

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

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

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

8. a part of the subpixel constitutes a light-emitting region that emits light when an electric field is applied thereto; The method for manufacturing a display device according to claim 6 , wherein the wettability of the light-emitting region is higher than the wettability of a region other than the light-emitting region in the subpixel.

9. 9. The method for manufacturing a 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 allow a portion of ink that has landed on one subpixel to flow into the other subpixel.

10. 10. The method for manufacturing a display device according to claim 9, wherein the ink flow paths connecting the sub-pixels that emit light of a first color extend in a direction oblique to a direction in which the ink flow paths connecting the sub-pixels that emit light of a second color extend.

11. The method for manufacturing a display device according to claim 9 or 10, 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 method for manufacturing a display device according to claim 9 , wherein the plurality of sub-pixels that emit light of one predetermined color are connected in a matrix via the ink flow path.

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

14. 14. The method of claim 13, wherein adjacent sub-pixels that emit the same color have different shapes.

15. The method for manufacturing a display device according to claim 1 , wherein an area of ​​at least one of the plurality of subpixels emitting light of the same color is different from an area of ​​the other subpixels.

16. 16. The method of claim 15, wherein adjacent sub-pixels that emit light of the same color have different areas.

17. In the first process and the second process, the printing direction of the inkjet device can be changed by 90 degrees from the first direction to the second direction by changing the moving direction of the stage on which the substrate is placed and the angle of the nozzle head, by rotating the stage by 90 degrees, or by using a plurality of the inkjet devices. The method for manufacturing a display device according to claim 16.

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