Apparatus and method for printing on substrates for display manufacturing - Patents.com

Abstract

An apparatus is provided for printing onto substrates for display manufacturing, the apparatus including an alignment station for aligning the substrate, a print station for printing onto the substrate, and an inspection station for inspecting the printed substrate for defects, the alignment station, the print station, and the inspection station arranged along a common axis, the common axis configured to move the substrate from the alignment station to the print station, and from the print station to the inspection station, the common axis further configured to move the printed substrate from the inspection station back to the print station, provided that defects are detected at the inspection station, the print station configured to correct the detected defects by reworking the printed substrate and reprinting onto the substrate.

Description

[Technical field]

[0001]

[0001] Embodiments of the present invention relate to apparatus and methods for printing on substrates for display manufacturing, particularly for manufacturing micro LED based displays, particularly displays including quantum dot based dyes. Embodiments of the present invention relate specifically to apparatus and methods for performing printing and rework operations on a substrate along a common axis. Further embodiments relate to an apparatus having a printhead and a printbar for printing on substrates for display manufacturing. [Background technology]

[0002]

[0002] In display manufacturing, several techniques are known and many approaches have been developed to provide displays with improved resolution and contrast characteristics. While LCD (Liquid Crystal Display) utilizes the dimming properties of liquid crystals to affect the light provided by a backlight source or reflector to generate color or monochrome images, OLED (Organic Light Emitting Diode) display technology provides organic materials that directly emit visible light in response to electrical power.

[0003]

[0003] OLED displays are known to have beneficial effects as opposed to LCDs, for example they can provide thinner and lighter displays, they achieve deeper black levels and higher contrast ratios, and they are flexible and transparent, allowing their use in multiple applications such as screens, televisions, and smartphones.

[0004]

[0004] The production of an OLED substrate is typically performed by coating organic materials on a substrate. The organic materials emit the primary colors red, blue, and green to produce pixels on the substrate. The coating process can be based, for example, on the evaporation of organic materials (e.g., host materials and dopant materials) deposited on the substrate to provide pixels of different colors on the substrate.

[0005]

[0005] In contrast to OLED technology, micro LEDs (light emitting diodes) allow for the provision of microscopically small pixels on a substrate. Micro LEDs are made of inorganic materials (e.g., indium gallium nitride (InGaN)) that are provided as semiconductor arrays, and they are capable of self-illumination in response to electrical power. Micro LED technology offers advantages in display manufacturing compared to OLED technology, such as the lifetime, brightness, and contrast of the resulting display. So far, the manufacture of micro LED arrays suitable for display manufacturing has been expensive and inefficient. Furthermore, it is difficult to provide color pixels.

[0006]

[0006] An approach to provide colored pixels in micro LED based displays is to use fluorescent dyes, which are excited by the light emitted by the micro LEDs and thus emit a specific radiation pattern, such as wavelength bands corresponding to the colors red, green and blue. Quantum dot dyes are suitable for this purpose. The dyes are typically applied by a printing process to specific locations on the substrate that correspond to the locations of the micro LEDs. A suitable printing process for providing the dyes on the substrate can be a limiting factor in the cost and time efficient production of high quality displays.

[0007] In view of the above, it would be beneficial to provide an improved apparatus or method for printing onto substrates for display manufacturing. Summary of the Invention

[0008] According to one aspect, there is provided an apparatus for printing onto a substrate for display manufacturing, the apparatus including an alignment station for aligning the substrate, a print station for printing onto the substrate, and an inspection station for inspecting the printed substrate for defects, the alignment station, the print station, and the inspection station arranged along a common axis, the common axis configured to move the substrate from the alignment station to the print station, and from the print station to the inspection station, the common axis further configured to move the printed substrate from the inspection station back to the print station, provided that defects are detected at the inspection station, the print station configured to correct the detected defects by reworking the printed substrate and reprinting onto the substrate.

[0009] According to a further aspect, there is provided a method for printing on a substrate for display manufacturing, the method including: loading a substrate at a loading position along a common axis, moving the substrate along the common axis from the loading position to an alignment station along the common axis, aligning the substrate, moving the substrate along the common axis from the alignment station to a print station along the common axis, printing on the substrate, moving the printed substrate along the common axis from the print station to an inspection station along the common axis, and inspecting the printed substrate. The method further includes, on a condition that a defect is detected in the printed substrate, performing the following four operations: moving the defective printed substrate back along the common axis from the inspection station to the print station, correcting the detected defect by reworking the defective printed substrate and reprinting on the substrate at the print station, moving the defective printed substrate along the common axis from the print station to the inspection station, and inspecting the reworked printed substrate. The method includes, provided that no defects are detected in the printed substrate, moving the printed substrate from the inspection station along the common axis for further processing.

[0010] According to an aspect, printing as described herein, such as printing in a print station of an apparatus as described herein, or a printing operation according to a method as described herein, may include printing an ink onto a substrate. The ink may be a UV ink, such as an ink containing phosphors or an ink containing quantum dot pigments. A UV ink may be defined by the ink's absorption at wavelengths or wavelength bands below 500 nm (e.g., in the range of 350 nm to 480 nm, below 450 nm, or between 385 nm and 400 nm). The UV ink may be excited by the absorption of light to fluoresce at higher wavelengths. Printing may include applying the ink to a predetermined location on the substrate. The predetermined location on the substrate may correspond to the location of one or more micro LEDs.

[0011] According to one aspect, the ink can be applied such that the ink is illuminated by a single micro LED or a specific or defined set of micro LEDs among many micro LEDs and not illuminated by other micro LEDs. According to one embodiment, the ink can be dispensed in the form of droplets onto a substrate to form an ink spot. The ink spot can be illuminated by a micro LED provided at a predetermined location of the ink spot, such that activation of the micro LED specifically illuminates the ink spot, but not other ink spots. The ink spot can be limited in size, for example, depending on the size of the micro LED and the illumination area provided by the micro LED when activated, and for example, such that the ink spot is not illuminated by other micro LEDs.

[0012]

[0011] According to one aspect, ink, such as an ink spot resulting from applying a droplet of ink onto a substrate, can form a component of a pixel of a display device. For example, a pixel can be composed of four adjacent ink spots each separately illuminated by four separate micro LEDs. For example, one ink spot provides red light, two ink spots provide green light, and one ink spot provides blue light when illuminated by a corresponding micro LED. In this embodiment, a pixel can include ink spots and corresponding micro LEDs arranged in a 2x2 pattern. Other pixel arrangements are suitable as well.

[0013] According to one aspect, printing may include inkjet printing, i.e., the use of an inkjet printhead and / or inkjet printing method. Inkjet printing may include ejecting ink from multiple nozzles in a printhead such that a droplet or series of droplets of ink is applied to a surface opposite the nozzles, such as a substrate as described herein. In some embodiments, inkjet printing may include delivering multiple smaller droplets to the same location. Inkjet printing is typically performed by moving the substrate to be printed relative to the printhead and timing the operation of the nozzles so that ink is ejected at the desired location.

[0014]

[0013] According to one embodiment, the substrate can be a glass substrate or a polymer substrate, in particular a substrate for display manufacturing. The substrate can have a size of 160mm x 120mm up to 640mm x 480mm, for example 320mm x 240mm, or above or below a given range. The substrate can be rectangular or of another shape. The substrate can be square, circular, hexagonal, or a collection of smaller substrates on a larger carrier substrate. The substrate can have a thickness of 0.1mm to 1mm, for example 0.5mm.

[0015] According to one aspect, the substrate may include structural features to aid in the specific application of the ink to the desired location. Such features may include surface modifications of the substrate to prevent the ink from spreading over a desired boundary, e.g., over a desired limited size of the ink spot. The substrate may be modified to further prevent undesired mixing of the inks, e.g., when a first drop or ink spot contacts a second drop or ink spot. Possible surface modifications may include providing a patterned substrate, such as a substrate having a patterned surface. The patterning of the substrate may include providing a pattern on the surface of the substrate that receives the ink. For example, a pattern of depressions in the substrate may be provided according to the desired pixel structure, i.e., the desired location of the ink spot. The substrate modification may be in the form of microwells in the substrate surface. The microwells receive the printed or ejected ink (e.g., the ejected ink droplets) and retain the ink therein, in particular until the ink is cured. Other types of structures may be suitable as well, for example barriers (particularly enclosures formed by hydrophilic inks (e.g., for hydrophobic inks) or hydrophobic barriers (e.g., for water-based inks) on the substrate surface to prevent the ink from spreading across the barrier). In beneficial embodiments, the surface modification of the substrate increases the spatial tolerance for applying ink droplets thereto, for example, an ink droplet may be dispensed anywhere within a well or other feature included in a pattern provided by the surface modification on the substrate, and the ink may then spread within the well, for example, to produce a desired uniform ink spot.

[0016]

[0015] According to one aspect, despite recent advances in the increased accuracy and repeatability of printing methods, particularly inkjet printing methods, and in the use of advanced surface structures as described above, the large number and small size of structures such as pixels used in the manufacture of modern display devices can sometimes result in errors during the printing process, resulting in a number of defects on the printed substrate. Possible defects include missing ink, uneven or incomplete application, mixing of two ink spots, application of ink spots in undesired locations, etc. To avoid discarding such defective substrates, the defective substrates can be reworked to correct the defects, resulting in a correctly printed substrate. Reworking can include application of ink to the locations where the ink spots are missing. Reworking can include cleaning and / or bleaching the ink in certain locations on the substrate, and applying ink to the cleaned and / or bleached locations.

[0017]

[0016] Known rework methods for reworking printed substrates, particularly for reworking printed substrates for display manufacturing, can be complex or time consuming and often require additional mechanical and manual interaction with the printed substrate, such as unloading the substrate from the main printing line and loading the substrate into a rework station.

[0018]

[0017] In view of the above, it is desirable to provide an apparatus according to the embodiments described herein that is suitable for printing on a substrate and further suitable for performing reworking of a printed substrate, and a method according to the embodiments described herein that includes operations for printing and reworking a printed substrate.

[0019]

[0018] The embodiments described herein are also directed to apparatus for carrying out the disclosed methods, including apparatus parts for carrying out each method aspect described. These method aspects may be implemented using hardware components, a computer programmed by appropriate software, any combination of the two, or in any other manner. Additionally, embodiments of the present disclosure are also directed to methods for operating the described apparatus, including method aspects for performing any function of the apparatus.

[0020]

[0019] So that the above features can be understood in detail, a more particular description may be had of the above briefly outlined embodiments by reference to the accompanying drawings, in which: [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 shows a schematic side view of a first embodiment of a printing device. [Diagram 2] FIG. 2 shows a schematic side view of a second embodiment of a printing apparatus; [Diagram 3] 1 illustrates a method of printing on a substrate, according to an embodiment. [Figure 4A] 1 shows a conventional printhead. [Figure 4B] 1 illustrates a printhead according to an embodiment described herein. [Figure 5A-5D] 1 illustrates an example of a printbar according to embodiments described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022]

[0020] Reference will now be made in detail to various embodiments, one or more examples of which are illustrated in the figures. In the following description of the drawings, like reference numerals refer to like components. Generally, only the differences with respect to individual embodiments will be described. Each example is provided by way of explanation only and is not meant to be limiting. Furthermore, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield still further embodiments. It is intended that this description include such modifications and variations.

[0023]

[0021] In this disclosure, reference is made to embodiments that include a substrate, which may be described in terms of its assigned attributes, such as a "printed substrate," a "defective substrate," or a "reworked substrate," which are intended to aid in the understanding of this disclosure and are not to be understood as limiting in any way.

[0024]

[0022] Figure 1 shows an apparatus 100 for printing on a substrate 150 for display manufacturing according to an embodiment. The apparatus includes an alignment station 110, a printing station 120 and an inspection station 130. The stations 110, 120 and 130 are arranged along a common axis 160. According to an embodiment, a substrate 150 is provided. The substrate 150 may be provided on or may comprise a substrate assembly, for example the substrate may be provided on a substrate holder, substrate carrier or the like. According to an embodiment, the substrate 150 may be a substrate to be printed, i.e. the apparatus 100 may be configured for a first printing of the substrate 150. According to a further embodiment, the substrate may be partially printed, i.e. the apparatus 100 may be configured for performing a printing operation of a series of printing operations.

[0025] According to an embodiment, as shown in Figure 1, the apparatus 100 can receive a substrate 150 at a substrate entry position and transport the substrate 150 to an alignment station 110. In Figure 1, the substrate is shown inside the alignment station 110. According to Figure 1, the transport of the substrate to the alignment station 110 is shown as transport 140. The transport of the substrate 150 can be performed by a common shaft 160 configured to transport the substrate.

[0026] According to an embodiment, the alignment station 110 aligns the substrate 150. Aligning the substrate 150 may include determining the position of the substrate 150, for example, by an optical alignment system. The position of the substrate may be determined relative to the apparatus 100 or a component of the apparatus 100, such as the common axis 160 or the print station 120. The determined position of the substrate 150 may include information about the lateral offset of the substrate 150 and / or the rotational offset of the substrate 150. The alignment station 110 may align the substrate 150 according to fiducial markers provided on the substrate 150 and / or the substrate holder, the edge position of the substrate 150, and / or the position of features including pixel structures provided on the substrate 150. The position of the features including pixel structures may include, for example, surface modifications on the substrate 150 as described above, the position of micro LEDs, or further such features.

[0027] According to an embodiment, aligning the substrate 150 may include performing corrective actions on the substrate 150, such as rotating and translating the substrate 150 along one or more axes to bring the substrate 150 into an aligned position. The corrective actions on the substrate 150 may be performed within the alignment station 110 and / or may be performed at a subsequent station, such as a second alignment station, or at another station, such as the print station 120. The corrective actions may be performed by the substrate holder, for example, at any position along the common axis 160.

[0028] According to an embodiment, aligning the substrate 150 may include providing the determined position of the substrate to further components of the apparatus 100, such as the print station 120 and / or the inspection station 130, and performing the station operations according to the determined position of the substrate 150. In this advantageous embodiment, the correction operation of the substrate 150 may be omitted. According to an embodiment, a possible offset may be corrected by performing an operation, such as printing on the substrate, according to the offset, so as to eliminate the offset. According to an embodiment, aligning the substrate 150 in the alignment station 110 may include determining the position of the substrate 150 and making the determined position of the substrate 150 available to further components of the apparatus 100, such as the print station 120. After receiving the determined position of the substrate 150, the print station 120 may print the substrate 150 at the desired position by adjusting the print position, i.e. the position where the ink is applied, according to the determined position.

[0029] According to an embodiment, as shown in Figure 1, the apparatus 100 is configured to transport the substrate 150 from the alignment station 110 to the print station 120. According to Figure 1, the transport of the substrate 150 to the print station 120 is shown as transport 142. The transport of the substrate 150 can be performed by a common shaft 160 configured to transport the substrate 150.

[0030] According to an embodiment, print station 120 prints on substrate 150. Operation of print station 120 may be performed according to the embodiments described herein, particularly those described in more detail herein with respect to printheads, printbars, ink types and applications, and other aspects or embodiments. After substrate 150 has been printed, it may be printed substrate 150.

[0031] According to an embodiment, as shown in Figure 1, the apparatus 100 is configured to transport the substrate 150 from the print station 120 to the inspection station 130. According to Figure 1, the transport of the substrate 150 to the inspection station 130 is shown as transport 144. The transport of the substrate 150 can be performed by a common shaft 160 configured to transport the substrate 150.

[0032] According to an embodiment, the inspection station 130 inspects the substrate 150, in particular the printed substrate 150. The inspection station 130 may be an optical inspection system, such as a visual inspection station, such as a camera-based visual inspection system or station. Inspecting the substrate 150 may include detecting defects on the substrate 150, in particular the printed defects, such as the defects mentioned above. The inspection station 130 may perform operations for detecting defects on the printed substrate 150. According to an embodiment, the inspection station 130 may manipulate the substrate 150, for example by manipulating a set of micro LEDs provided on the substrate 150, in order to detect whether the light emitted by the micro LEDs and / or the pigments (e.g. one or more ink spots) provided on the substrate 150, in particular the properties of the pigments, in particular the absorbed and / or emitted light of the pigments, correspond to desired parameters. According to one embodiment, the inspection station 130 can provide light to the substrate in the absorption wavelength range of a pigment provided on the substrate 150 (e.g., a pigment contained in an ink printed on the substrate 150 at the print station 120) to detect whether the light emitted by the pigment, e.g., at the emission wavelength of the pigment, corresponds to a desired parameter. According to an embodiment, the inspection station can localize defects on the substrate 150 and provide defect data, e.g., including the location and / or type of the defect, to further components of the apparatus 100, in particular the print station 120.

[0033] According to an embodiment, as shown in Fig. 1, the apparatus 100 may be configured to transport the substrate 150 from the inspection station 130 to a further processing station and / or to an unloading position (not shown). According to Fig. 1, the transport of the substrate 150 from the inspection station 130 is shown as transport 148. The transport of the substrate 150 may be performed by a common shaft 160 configured to transport the substrate 150. The transport 148 may be performed conditionally, i.e. only if no defects were detected at the inspection station 130.

[0034] According to an embodiment, as shown in Fig. 1, the apparatus 100 is configured to transport the substrate 150 back from the inspection station 130 to the print station 120. According to Fig. 1, the return transport of the substrate 150 from the inspection station 130 to the print station 120 is shown as transport 146. The transport of the substrate 150 can be performed by a common shaft 160 configured to transport the substrate 150. The transport 146 can be performed conditionally, i.e., if a defect is detected at the inspection station 130.

[0035]

[0033] According to an embodiment, as shown in FIG. 1, the apparatus 100, specifically the print station 120, is configured to rework the printed substrate 150 in order to correct defects on the substrate, such as defects detected by the inspection station 130, by printing again on the defective substrate 150, i.e., by reprinting or reworking the substrate 150. The print station 120 may be configured to receive data from other components of the apparatus 100, such as defect data provided by the inspection station 130. The print station 120 may be configured to evaluate the data and perform printing operations according to the data. In one embodiment, if a defect location is detected on the printed substrate 150, the defective substrate 150 is moved to the print station 120, and the defect is corrected by ejecting ink at the defect location. According to an embodiment, following reworking at the print station 120, the reworked substrate 150 may be transported again to the inspection station 130 for inspection by repeating the operations as described above.

[0036]

[0034] According to an embodiment, a number of redundant micro LEDs may be provided on a substrate. If a defect is detected, reprinting or reworking the substrate as described above may include using the print station 120 to print ink at a predetermined location corresponding to the location of the redundant micro LED. In one embodiment, a redundant micro LED may be provided next to a defective micro LED. If a defect based on a defective micro LED is detected, the redundant LED may be utilized to replace the function of the defective micro LED. It should therefore be understood that reworking a defective substrate is not limited to reworking a defective printed substrate.

[0037] 1, the apparatus 100 includes a common shaft 160. The common shaft is configured to move the substrate 150 from the alignment station 110 to the print station 120, and from the print station 120 to the inspection station 130. The common shaft 160 is further configured to move the printed substrate 150 from the inspection station 130 back to the print station 120, provided that defects are detected at the inspection station 130.

[0038]

[0036] According to an embodiment, the common axis 160 is specifically configured to maintain a defined position of the substrate 150 when moving the substrate 150 according to the above-mentioned operations. The defined position of the substrate 150 can be defined as not exceeding a deviation from an expected substrate 150 position. The defined position can be defined not exceeding a position deviation of the substrate. The position deviation of the substrate exceeds a minimum feature size of the substrate 150, such as a pixel, a well, or a size or spacing of a micro LED or a series of micro LEDs. The maximum position deviation can be in the range of 200 μm, 100 μm, 50 μm, specifically in the range of 40 μm to 60 μm, or in the range of 20 μm to 40 μm, or in the range of 5 μm to 20 μm, or in the range of 1 μm to 10 μm. The common axis 160 can be configured to transport the substrate 150 over a desired position of the substrate 150 in the apparatus 100. Common axis 160 can affect or move the movement of the substrate within or across the stations of apparatus 100, specifically print stations 120 and / or inspection station 130. According to an embodiment, once substrate 150 is aligned, common axis 160 can move substrate 150 to any position along the common axis such that the position of substrate 150 is known relative to apparatus 100 or components of apparatus 100.

[0039] According to an embodiment, the common axis 160 includes a stator of a linear motor, specifically a high-precision linear motor. The linear motor may be configured to move the substrate 150 along the common axis 160. The linear motor may be a linear induction motor. The linear motor may be a synchronous linear motor. The linear motor may be a piezoelectric linear motor. The linear motor may be a linear stepper motor. Additional linear motor technologies may be utilized. A combination of linear motor technologies may be utilized. According to an embodiment, the apparatus 100 includes a substrate holder. The substrate holder may include a reaction plate for engaging with a stator of the linear motor, the reaction plate including, for example, a set of magnets, permanent magnets, coils, latch structures, etc. The reaction plate may be a structure for engaging with the linear motor propelled by the linear motor. The substrate holder may include additional actuators for moving (e.g., rotating or translating) the substrate along additional axes other than the common axis 160, for example, for alignment or assistance in aligning the substrate.

[0040] According to embodiments, the common axis may be linear, as shown in Figure 1. According to further embodiments, the common axis may have further shapes, such as shapes provided by including corners or curves in the common axis. Non-linear arrangements of the common axis may beneficially reduce the floor space of the apparatus 100.

[0041]

[0039] Referring now to Figure 2, there is shown an apparatus 200 for printing substrates for display manufacture, according to an embodiment. The apparatus 200 includes some of the features of the apparatus 100. The apparatus 200 differs from the apparatus 100 in that a further processing station 222 is provided along the common axis 160 between the print station 120 and the inspection station 130.

[0042] According to an embodiment, the processing station 222 may be a secondary print station in addition to the print station 120. According to one example, the print station 120 may eject a first ink at a defined location on the substrate 150, and the secondary print station may eject a second ink at a defined location on the substrate 150. In this example, the first ink may be a first color ink and the second ink may be a second color ink. The secondary print station may provide redundancy, for example, in the event that the print station 120 fails.

[0043] According to an embodiment, the processing station 222 may be a curing station for curing the substrate 150 after printing. Curing the substrate 150 may include providing radiation, such as light or heat, in particular UV light, to the substrate 150 to cure ink printed on the substrate 150 at the print station 120.

[0044]

[0042] According to an embodiment, the processing station 222 may be a component of a rework process, such as a cleaning station and / or a bleaching station for cleaning or bleaching the substrate 150 or defined locations on the substrate 150 if defects are detected at the inspection station 130.

[0045] According to embodiments, the processing station 222 may be a combination of processing stations, such as several secondary print stations, a print station and a curing station, etc. According to embodiments, the processing station 222 may be an optional processing station, i.e., the operation of the processing station 222 may be optional or unrelated to the printing process described herein.

[0046] According to an embodiment, as shown in Fig. 2, the apparatus 200 is configured to transport the substrate 150 from the print station 120 to the processing station 222. According to Fig. 2, the transport of the substrate 150 to the processing station 222 is shown as transport 240. According to an embodiment, the apparatus 200 is further configured to transport the substrate 150 from the processing station 222 to the inspection station 130. According to Fig. 2, the transport of the substrate 150 from the processing station to the inspection station is shown as transport 242. According to an embodiment, the transport of the substrate 150 can be performed by a common shaft 160 configured to transport the substrate 150.

[0047] According to an embodiment, as shown in Fig. 2, the device 200 is configured to transport the substrate 150 back from the inspection station 130 to the printing station 120. This is done in particular by first transporting the substrate 150 to the processing station 222 and then transporting the substrate 150 from the processing station 222, i.e. through the processing station 222, to the printing station 120. According to Fig. 2, the return transport of the substrate 150 from the inspection station 130 to the printing station is shown as transport 244 and transport 246. The transport of the substrate 150 can be performed by a common shaft 160 configured to transport the substrate 150. The transports 244 and 246 are performed conditionally, i.e. if a defect is detected at the inspection station 130.

[0048]

[0046] Referring now to Figure 3, according to an embodiment, an apparatus 300 for printing on a substrate for display manufacturing is provided. The method may be performed according to the operations disclosed herein, in particular the operations performed by the embodiments described with respect to the apparatus described in relation to Figures 1 and / or 2. The method includes loading 302 a substrate at a loading position arranged along a common axis, moving 304 the substrate along the common axis from the loading position to an alignment station arranged along the common axis, aligning 306 the substrate, moving 308 the substrate along the common axis from the alignment station to a print station arranged along the common axis, printing 310 on the substrate, moving 312 the printed substrate along the common axis from the print station to an inspection station arranged along the common axis, and inspecting 314 the printed substrate. The method further includes, on condition that defects are detected in the printed substrate, performing the following four operations: moving the defective printed substrate back along the common axis from the inspection station to the print station 320, reworking the defective printed substrate to reprint the substrate at the print station to correct the detected defects 322, moving the defective printed substrate along the common axis from the print station to the inspection station 324, and inspecting the reworked printed substrate 326. The method includes, on condition that defects are not detected in the printed substrate, moving the printed substrate from the inspection station along the common axis 330 for further processing.

[0049] According to an embodiment, aligning 306 can be performed in an alignment station, such as alignment station 110. According to an embodiment, printing 310 can be performed in a printing station, such as printing station 120. According to an embodiment, inspecting 314 can be performed in an inspection station, such as inspection station 130. According to an embodiment, the movement operations, such as movement operations 304, 308, 312, 320, 324, 330, and / or 342, can be performed by or include a common axis movement, such as common axis 160. According to an embodiment, the method can include further operations, such as operations performed by processing station 222. According to an embodiment, the operations of the method can be performed in an alternative order or combination of operations, for example, aligning 306 the substrate can include alignment printing 310 on the substrate, for example printing 310 according to a specified position of the substrate.

[0050]

[0048] According to an embodiment, as shown in Figure 3, the method may specifically include repeating rework 340 if defects are found upon inspection after the first rework. Repeating the rework may include performing any of the actions from 320 through 326.

[0051]

[0049] According to an embodiment, as shown in FIG. 3, the method may specifically include, after reworking 322 the substrate and inspecting 326 the substrate, allowing further processing 342 if no further defects are detected on the substrate.

[0052] According to an embodiment, a print station disclosed herein, such as print station 120 or a station for performing printing 310, may include a print head, such as one or more print heads, for printing ink on a substrate. Possible print heads include ejection print heads, laser transfer print heads, or in particular inkjet print heads. The inkjet print head may be a ceramic inkjet print head suitable for high volume applications. The inkjet print head may be a piezo-actuated print head. The inkjet print head is suitable for ejecting ink droplets with a volume of 6-42 picoliters, in particular ink droplets with a volume of 1-10 picoliters. The print head may print an ink as described above, in particular a curable ink, in particular an ink containing a fluorescent dye, such as a quantum dot dye.

[0053]

[0051] Referring now to Figure 4A, a conventional inkjet printhead 400 is illustrated as an example, showing a portion of the surface of the printhead 400 facing the substrate to be printed. The printhead may be a commercially available printhead, for example a Xaar 1003 printhead. The printhead 400 has a number of nozzles 420 for ejecting ink, particularly in the form of droplets. Nine nozzles 420 are shown in Figure 4A, but only one nozzle is labeled with a reference number for better clarity of the drawing. A typical relative direction of movement of a substrate 410 is shown. As shown in Figure 4A, the nozzles of a conventional printhead are staggered with respect to the direction of movement of the substrate 410. When printing, the conventional printhead 400 typically operates such that the nozzles eject ink in a timed manner according to the staggered arrangement and the speed of the substrate, but if the substrate is printed while moving strictly in translation along the direction in which the nozzles are staggered, the effect of the staggered nozzle configuration is negated. However, if the substrate is printed at an angle to the printhead, i.e. in a direction that is not strictly parallel to the staggered nozzle direction, the spacing between the nozzles will be non-uniform, and therefore most or all of these printing angles are often ineffective when uniform spacing between the nozzles and the position of the ink ejected from the nozzles is desired.

[0054]

[0052] Referring now to Figure 4B, an embodiment of a printhead 401 is shown. The printhead 401 includes some of the features of the conventional printhead 400. The printhead 401 differs from the conventional printhead 400 in that the nozzles 420 are arranged in a linear fashion, specifically in a non-staggered fashion. An example of a staggered fashion is described in relation to the conventional printhead 400. A linear nozzle fashion may be defined as the nozzles 420 that have a maximum misalignment, offset, or misalignment in a direction perpendicular to the row of nozzles. The maximum misalignment, offset, or misalignment may be defined as less than 10% (e.g., less than 5%, less than 2%, less than 1%, or less than 0.1%) of the spacing between the nozzles.

[0055] According to an embodiment, as shown in FIG. 4B, the nozzles 420 may be equally spaced or uniform. That is, the distance between adjacent nozzles may be equal or effectively equal. The spacing of the nozzles may define the resolution of the nozzles 420 and / or the row of the print head 401. The print head 401 may have a plurality of nozzles spaced at least 150 nozzles per inch (npi), such as 150-160 npi or more than 160 npi. The print head may have a plurality of nozzles arranged in a line. The plurality of nozzles arranged in a line may include at least 250 nozzles, at least 300 nozzles, 300-500 nozzles, or at least 500 nozzles. In addition to a single row of nozzles, the print head 401 may have multiple rows of nozzles arranged in a line (e.g., two rows of nozzles, three rows of nozzles, or more than three rows of nozzles). The linearly arranged rows of nozzles may be two rows of nozzles spaced apart along the direction of movement of the substrate 410, specifically, two parallel rows of nozzles.

[0056] According to embodiments, the print head 401 is configured to deliver a single droplet of ink to each desired location on the substrate. Therefore, it is desirable for the location of the nozzles delivering ink onto the substrate to be aligned with the desired location on the substrate along the direction of movement of the substrate 410. The print head 401 may have a spacing of nozzles 420 as described above. According to some embodiments, the spacing of the nozzles may be less than the desired spacing for selectively printing on the substrate in the printing process. For example, the spacing of the desired locations on the substrate may be n nozzles per inch along a direction perpendicular to the direction of movement of the substrate 410, and the inherent spacing of the print head may be m nozzles per inch, where n>m. The spacing of the nozzles may be altered by angling the print head, i.e., the row of nozzles contained in the print head. Spacing m i depends on the angle α and the characteristic spacing m of the printheads as follows: m i = m sin α -1

[0057] According to an embodiment, the nozzles 420 of the print head 401 are arranged along a straight line. Thus, the spacing of the nozzles 420 remains uniform as described above, especially when angled. According to an embodiment, the angle α can be selected for the print head 401 such that the spacing of the nozzles 420 of the angled print head perpendicular to the direction of movement of the substrate 410 corresponds to the spacing of the desired locations to be printed on the substrate.

[0058] According to embodiments, the print head 401 can be provided at an angle between 0° and 90°. An angle of 90° corresponds to an arrangement as shown in FIG. 4B, where the row of nozzles extends perpendicular to the direction of movement of the substrate. An angle of 0° corresponds to the row of nozzles extending parallel to the direction of movement of the substrate. Further advantageous embodiments include providing the print head at an angle between 10° and 90°, or between 20° and 90°, in particular between 30° and 90°, 35° and 90°, or between 40° and 90°.

[0059]

[0057] Advantages of the embodiments include the ability to provide higher print resolution with a lower resolution printhead and greater flexibility in printing on a variety of substrates, particularly substrates having different feature resolutions, without the need to change printheads between multiple substrate batches containing substrates of different resolutions.

[0060] 5A and 5B, multiple arrangements of printheads 401 disposed within print bars 501, 502, 503, and 504 are shown viewed from above the surface of substrate 550, according to an embodiment. The print bars may be disposed on or within a print station, such as print station 120 or a station for printing 310. The print heads 401 may be print heads according to embodiments described herein. The print heads 401 may be stationary within print station 120 during printing of substrate 550. In particular, print station 120 may be configured such that the print heads do not need to move relative to the print station during printing. The print bars 501, 502, 503, and 504 may include multiple print heads 401, such as one print head, two print heads, three print heads, four print heads, five to eight print heads, or five to ten print heads. By increasing the number of print heads, the maximum printable size and / or the size of the substrate 550 to be printed on can be increased, specifically the maximum width of the substrate 550 along a direction perpendicular to the direction of movement of the substrate 510.

[0061] According to an embodiment, as shown in Figures 5A and 5B, the substrate 550 may be larger than the maximum printable size, however, it may be beneficial for the maximum printable size to be equal to or greater than the width of the substrate, specifically, for the entire area of ​​the substrate to be printable.

[0062] According to an embodiment, as shown in Figures 5A and 5B, the substrate 550 has a movement direction 510 through a print station including print bars 501, 502, 503, or 504. According to an embodiment, this movement can be effected by moving the substrate on a common axis, specifically with or by a common axis. The print bars 501, 502, 503, or 504 can be disposed inside the print station. The print bars 501, 502, 503, or 504 can be provided in a fixed position inside the print station during a printing process for printing on the substrate 550.

[0063] According to an embodiment, the print bars 501, 502, 503 or 504 may include actuators for modifying the position of the print bars 501, 502, 503 or 504, in particular with respect to the position of the substrate 550, such as a specific position provided by the alignment station 110. The change of position may include translating or rotating the print bars 501, 502, 503 or 504 with respect to the substrate 550. The modification of the position may allow for the alignment of the print station 120, in particular with respect to the substrate 550, for example, in response to a specific position of the substrate provided by the alignment station 110. In the context of the present disclosure, the alignment of the print stations, in particular the components of the print stations, such as the print heads 501, 502, 503 or 504, with respect to the substrate may be understood as the alignment of the substrate.

[0064] 5A and 5B, according to embodiments, print head 401 may be positioned at various angles within print bar 501, 502, 503, or 504 such that the angle of the row of nozzles 520 is positioned at angle 560, 562, 564, or 566 relative to the direction of movement of substrate 510. Specifically, if the desired spacing of features on substrate 550 does not correspond to the inherent spacing of nozzles of print head 401, the print head may be positioned at an angle for reasons discussed above.

[0065] According to an embodiment, as shown in Figure 5A, the printbar 501 may include printheads 401 arranged such that the angle 560 of the row of nozzles 520 relative to the direction of movement of the substrate is 45°. Additional angles 562, as shown in Figure 5B, may also be possible, as in the range of angles mentioned above. According to an embodiment, care is taken to ensure that there is no overlap or gap between the outermost positions of the row of nozzles 520 between the printheads 401 along a direction perpendicular to the direction of movement of the substrate 410, thereby making it possible to print any or any desired position of the substrate.

[0066] According to an embodiment, as shown in FIG. 5B, the print bar 502 may include print heads 401 arranged such that the angle 562 of the row of nozzles 520 relative to the direction of movement of the substrate is 60°. Additional angles 562 may be possible, such as the range of angles discussed above. According to an embodiment, the print bar 502 may be a print bar 501 in a second arrangement. According to an embodiment, the print heads 401 provided within the print bar 501 and / or 502 may be arranged such that the angles 560, 562 of the print heads are adjustable. The angles 560, 562 may be adjustable by providing an actuator for actuating the print heads 401. The angles 560, 562 may be adjustable according to the desired characteristics of the print station, such as the desired spacing of the nozzles relative to the direction of movement of the substrate 510, as discussed above.

[0067] According to an embodiment, as shown in Figures 5A and 5B, the print bars 501, 502 may be configured to rotate the print heads 401 disposed thereon. In the illustrated embodiment, the print bars may remain stationary within the print station 120. The print heads may be rotated within the print bars 501, 502 to adjust the angles 560, 562 of the print heads relative to the direction of movement of the substrate 510.

[0068] According to an embodiment, as shown in FIG. 5C, the printbar 503 may include printheads 401 arranged such that the angle 564 of the row of nozzles 520 with respect to the direction of movement of the substrate 410 is 90°. Further angles 562 may be possible, such as the range of angles mentioned above. Thus, the spacing of the nozzles in the row of nozzles 520 corresponds to the available spacing of the positions at which ink can be ejected by the nozzles. According to an embodiment, care is taken to ensure that there is no overlap or gap between the outermost positions of the row of nozzles 520 between the printheads 401 along a direction perpendicular to the direction of movement of the substrate 410, so that it is possible to print any position or desired position of the substrate. In contrast to the embodiment of FIG. 5A or 5B, the printheads 401 of the printbar 503 are not arranged along a single row or direction, but are provided in two rows of printheads, the two rows of printheads being offset along a direction that may be the direction of movement of the substrate 510. Additional arrangements of printheads within printbars 501, 502, 503, or 504 are possible, such as more than two rows of printheads, or a combination of staggered printheads and printheads at various angles in a printbar.

[0069] According to an embodiment, as shown in FIG. 5D, the printbar 504 may be disposed at a constant angle such that the angle 566 of the row of nozzles 520 relative to the direction of movement of the substrate 410 is 70°. Further angles 566 may be possible, such as the range of angles discussed above. According to an embodiment, the printbar 504 may be the second arrangement of the printbar 503 or may be disposed at an alternative angle. According to an embodiment, the printheads 401 disposed within the printbars 503 and / or 504 may be disposed such that the angles 564, 566 of the printheads within the printbar remain stationary. According to an embodiment, the printbars 503, 504 may be disposed such that the printbars can be rotated relative to the direction of movement of the substrate 510 to adjust the angles 560, 562. By providing actuators for actuating (i.e., rotating) the printbars, the angles 560, 562 may be adjusted. The angles 560, 562 may be adjustable according to the desired characteristics of the print station, such as the desired spacing of the nozzles relative to the direction of movement of the substrate 510, as described above.

[0070]

[0068] An advantage of embodiments relating to print stations, particularly embodiments relating to print heads and / or print bars including print heads, may be high flexibility in printing, particularly printing on substrates for display manufacturing, particularly printing on substrates having features of various sizes or spacing or desired print positions corresponding to the features.

[0071]

[0069] Advantages of the embodiments described herein may include the effect of an apparatus or method's ability to perform printing and, optionally, subsequent rework steps on a substrate within a single manufacturing process or line, thereby increasing manufacturing speed and productivity, reducing costs and labor, and eliminating the need for additional manufacturing tools such as separate rework stations. Additionally, the overall quality of the printed substrates and display devices based thereon may be improved without significantly increasing the number of rejected or defective substrates, thereby enabling the manufacture of larger or higher resolution printed substrates.

[0072]

[0070] While the above is directed to several embodiments, other and further embodiments may be devised without departing from the basic scope, which is determined by the claims that follow.

Claims

1. 1. An apparatus for printing onto a substrate for display manufacturing, comprising: an alignment station for aligning said substrate; a print station for printing onto the substrate; and an inspection station for inspecting the printed substrate for defects; Equipped with the alignment station, the print station, and the inspection station are disposed along a common axis; the common shaft is configured to move the substrate from the alignment station to the print station and from the print station to the inspection station; the common shaft is further configured to move the printed substrate from the inspection station back to the print station upon a condition that a defect is detected at the inspection station; The apparatus, wherein the print station is configured to correct the detected defects by reworking the printed substrate and reprinting on the substrate.

2. The apparatus of claim 1 , wherein the common shaft comprises a stator of a linear motor.

3. the apparatus comprising a substrate holder; The apparatus of claim 2 , wherein the substrate holder comprises a reaction plate for engaging the stator of the linear motor.

4. The alignment station includes: The apparatus of claim 3 , configured to align the substrate according to a reference marker provided on the substrate holder.

5. The alignment station, A fiducial marker provided on the substrate; an edge position of the substrate; Location of features including pixel structures on the substrate The apparatus of claim 1 , configured to align the substrate according to at least one of:

6. An apparatus according to claim 1 , wherein the print station comprises a printhead for printing ink onto the substrate.

7. The apparatus of claim 6 , wherein the ink comprises a fluorescent dye comprising a UV-excitable fluorescent quantum dot dye.

8. 6. An apparatus according to claim 1, wherein the print station comprises a print head, the print head comprising a plurality of nozzles for ejecting ink, the plurality of nozzles being arranged along a straight line.

9. 6. The apparatus of claim 1, wherein the print station comprises a print head, the print head comprising a plurality of nozzles spaced at at least 150 nozzles per inch.

10. The apparatus of claim 8, wherein the print head has at least 250 nozzles per row.

11. the print station includes a print bar; the printbar comprises at least one printhead; the print head includes a plurality of nozzles for ejecting ink; The plurality of nozzles are arranged along a straight line, the at least one printhead is arranged such that an array of nozzles of the at least one printhead is disposed at an angle relative to a direction of movement of the substrate through the print station; 6. An apparatus according to claim 1, wherein an angle of the row of nozzles of the at least one printhead relative to a direction of movement of the substrate through the print station is between 0° and 90°.

12. The apparatus of claim 11 , wherein the print head is positioned such that an angle of the print head relative to a direction of movement of the substrate through the print station is adjustable.

13. 7. The apparatus of claim 6, wherein the printhead is mounted stationarily within the print station during printing.

14. The apparatus of claim 1 , wherein the inspection station comprises a vision inspection system including a camera-based vision inspection system.

15. and a curing station configured to cure the substrate.

6. The apparatus of claim 1, wherein the common shaft is configured to move the substrate from the print station to the curing station and from the curing station to the inspection station.

16. 1. A method for printing onto a substrate for display manufacturing, comprising: placing the substrate on a placement location along a common axis; moving the substrate along the common axis from the placement position to an alignment station disposed along the common axis; aligning the substrate; moving the substrate along the common axis from the alignment station to a print station disposed along the common axis; printing on the substrate; moving the printed substrate along a common axis from the print station to an inspection station disposed along the common axis; Inspecting the printed board; Provided that a defect is detected in the printed substrate, a) moving the defective printed substrate back along the common axis from the inspection station to the printing station; b) reworking the defective printed substrate by reprinting the substrate at the print station to correct the detected defects; c) moving the defective printed substrate from the printing station to the inspection station along the common axis; and d) inspecting the reworked printed circuit board; and and providing that no defects are detected in the printed substrate, moving the printed substrate from the inspection station along the common axis for further processing. The method includes:

17. the substrate is configured to provide a plurality of micro LEDs for specifically illuminating a location on the substrate; 6. The device of claim 1, wherein selected micro LEDs of the plurality of micro LEDs comprise pixels of a display.

18. The substrate, configured to provide a plurality of micro-LEDs for specifically illuminating a location on the substrate; 17. The method of claim 16, wherein a selected micro LED of the plurality of micro LEDs comprises a pixel of a display.

19. the print station is configured to selectively print ink at a plurality of locations on the substrate; 6. The apparatus of claim 1, wherein the ink is configured to form a component of a pixel of a display device when illuminated by a micro LED.

20. The print station configured to selectively print ink at a plurality of locations on the substrate; 19. The method of claim 16 or 18, wherein the ink is configured to form a component of a pixel of a display device when illuminated by a micro LED.

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