Jet control using substrate alignment features and print area alignment features

Abstract

In a printing method, at least one image of a substrate loaded in a printing system is acquired. Based on the at least one image, an actual position of a first alignment feature on the substrate in a reference system of the printing system is determined. Based on the actual position of the first alignment feature, an expected position of a second alignment feature on the substrate is determined. Based on the at least one image and the expected position of the second alignment feature, an actual position of the second alignment feature in a reference system of the printing system is determined. Based on the actual position of the second alignment feature, a target position of a printing area on the substrate is determined. Based on the target position of the printing area, a printing material is controlled to be ejected onto the substrate in the printing area.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 782,442 filed on December 20, 2018, U.S. Provisional Patent Application No. 62 / 891,807 filed on August 26, 2019, and U.S. Non-Provisional Application No. 16 / 716,143 filed on December 16, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] In general, embodiments of the present application relate to inkjet printing systems. In particular, jetting control methods, systems and / or devices used in inkjet printing systems are described. Background Art

[0004] Inkjet printing is common in office and home printers, as well as industrial printers for making displays, printing large written materials, incorporating materials into manufactured products such as PCBs, and constructing biological products such as tissues. Some printing applications, such as printing luminescent materials on display substrates, require extremely high positioning accuracy of the dispensing nozzle and / or the printing substrate. In some cases, if the placement error of the droplets of the printed material exceeds about 15μm, printing errors will result. Achieving this extremely high accuracy is affected by countless factors, such as manufacturing tolerances of printer components, thermal expansion, thermal non-uniformity, vibration, and the evolution of the characteristics of printer components over time. Differences in substrate preparation can also cause errors. In particular, before printing the luminescent material on the display substrate, the positioning pieces of the luminescent material are sometimes printed on the substrate. Changes or errors in the printing position can cause and compound errors in printing the luminescent material. In this aspect, a method, system and / or device for controlling the ejection of printing material in an inkjet printer is proposed. Summary of the invention

[0005] In a printing method according to one embodiment, at least one image of a substrate loaded in a printing system is acquired. Based on the at least one image, an actual position of a first alignment feature on the substrate in a reference system of the printing system is determined. Based on the actual position of the first alignment feature, an expected position of a plurality of second alignment features on the substrate is determined. Based on the at least one image and the expected position of the second alignment feature, the actual position of the plurality of second alignment features in the reference system of the printing system is determined. Based on the actual position of the second alignment feature, target positions of a plurality of printing areas on the substrate are determined. Based on the target positions of the printing areas, a printing material is controlled to be ejected onto the substrate in the plurality of printing areas.

[0006] In one embodiment, a printing system includes a substrate support for supporting a substrate; a print head assembly having a dispensing nozzle; at least one imaging device; and a controller. The controller is used to control the at least one imaging device to capture a first image of a plurality of first alignment features on the substrate. The controller is also used to determine the actual position of the first alignment features in a reference system of the printing system based on the first image. The controller is also used to determine the expected position of a plurality of second alignment features based on the actual position of the plurality of first alignment features. The controller is also used to control the relative positioning of the at least one imaging device and the substrate support based on the expected position of the second alignment features, so that the second alignment features can be imaged using the at least one imaging device. The controller is also used to control the at least one imaging device to capture a second image of the second alignment feature. The controller is also used to determine the actual position of the second alignment feature in the reference system of the printing system based on the second image. The controller is also used to determine the target position of a printing area corresponding to a group of the second alignment features based on the actual position of the second alignment features. The controller is also used to control the printing material from the dispensing nozzle of the print head assembly to be ejected onto the substrate in the printing area based on the target position of the printing area.

[0007] In one embodiment, a controller for a printing system includes at least one processor. The processor is used to receive image data of at least one alignment feature among a plurality of alignment features on a substrate that supports a printing job in the printing system. The processor is also used to determine the actual positions of the plurality of alignment features in a reference system of the printing system based on the image data. The processor is also used to determine the target positions of the pixels at the corners of a printing area on the substrate based on the actual positions of the plurality of alignment features. The processor is also used to determine the target positions of the pixels along the edge of the printing area based on the target positions of the pixels at the corners of the printing area. The processor is also used to determine the target positions of the pixels in the printing area based on the target positions of the pixels along the edge of the printing area. The processor is also used to control the ejection of printing material from a dispensing nozzle of a print head assembly of the printing system onto the substrate in the printing area based on the target positions of the pixels in the printing area.

[0008] In one embodiment, a flat panel display is made by a printing method, wherein at least one image of a substrate loaded in a printing system is acquired; based on the at least one image, an actual position of a first alignment feature on the substrate in a reference system of the printing system is determined; based on the actual position of the first alignment feature, expected positions of a plurality of second alignment features on the substrate are determined; based on the at least one image and the expected position of the second alignment feature, the actual positions of the plurality of second alignment features in the reference system of the printing system are determined; based on the actual position of the second alignment feature, target positions of a plurality of printing areas on the substrate are determined; and based on the target positions of the printing areas, the printing material is controlled to be ejected onto the substrate in the plurality of printing areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Various aspects of the present disclosure may be better understood with reference to the accompanying drawings and the following detailed description. It should be noted that, according to standard industry practice, the various features are not drawn to scale. In fact, the size of the various features may be arbitrarily increased or decreased for clarity.

[0010] Figure 1 It is a top-down isometric view of the printing system.

[0011] Figure 2 is a schematic top view of a printing system according to one embodiment.

[0012] Figure 3A is a schematic side view of a printing system according to one embodiment.

[0013] Figure 3B In the example Figure 3A Schematic top view of a substrate of a printing system.

[0014] Figure 4 is a flow chart of a printing method according to one embodiment.

[0015] Figures 5A-5D is based on Figure 4 Schematic plan view of a substrate or portion of a substrate processed during the various operations of the printing method shown.

[0016] Fig. 6A is a flow chart of a printing method according to one embodiment.

[0017] Figure 6B is based on Fig. 6A A schematic plan view of a printing area on a substrate processed by the printing method shown.

[0018] Figure 7 is a flow chart of a printing method according to one embodiment.

[0019] Figure 8is a block diagram of a controller according to one embodiment.

[0020] Fig. 9 is a schematic isometric view of a printing assembly according to one embodiment. DETAILED DESCRIPTION

[0021] The present disclosure then provides many different embodiments or examples to realize different features of the present invention. The specific examples of parts, values, operations, materials, configurations, etc. described below are intended to simplify the present disclosure. Of course, these examples are exemplary only and not restrictive. Other parts, values, operations, materials, configurations, etc. are expected. For example, for the purpose of brevity and clarity, the reference numbers and / or letters in each example of the present disclosure may be repeated, but the repetition itself does not indicate the relationship between the various embodiments and / or configurations discussed. For ease of explanation, spatial relationship terms such as "below", "below", "lower", "above", "upper", etc. may be used in this article to describe the relationship between an element or feature as shown in the figure and other elements or features. Spatial relationship terms are intended to include different directions when the device is used or operated except for the directions shown in the figure. If the device adjusts the direction (rotates 90 degrees or is in other directions) in other cases, the spatial relationship descriptors used in this article will be interpreted accordingly.

[0022] Some inkjet printing applications rely on high-precision positioning of the dispensing nozzle and / or the printing substrate to obtain high-quality printed products. In order to accurately dispense printing material to a small target location on a substrate using an inkjet printing system, it is necessary to determine the actual position of the substrate and / or its printing area in the reference frame of the inkjet printing system. Then, high-precision printing is performed using the actual position of the printing area defined by the reference frame of the printing system. The actual position of the printing area is determined based on one or more printing area alignment features on the substrate. The actual position of the printing area alignment feature is in turn determined based on one or more substrate alignment features. Therefore, in at least one embodiment, the actual position of all printing areas on the substrate can be determined in a single reference frame of the printing system, and a single "trigger" plan for the printing job can be formulated to print at all printing areas on the substrate while allowing for substrate manufacturing and / or printer measurement errors. Therefore, printing speed and accuracy are improved. This arrangement is superior to other methods, which provide a limited set of marks to determine the position of the substrate without a separate set of marks to determine the position of each printing area, and therefore, cannot correct errors between printing areas on the substrate.

[0023] Figure 1 is a top isometric view of printing system 100 .

[0024] The printing system 100 has a substrate support 102, a printing assembly 104, and a holder assembly 106 for manipulating the substrate for printing. The printing system 100 is built on a base 108, which in one example is a massive object to minimize the transmission of vibrations to the operating parts of the printing system 100. In one example, the base 108 is a block of granite. The substrate support 102 is located on the base 108 and includes a support surface 110 and a device to make the support surface 110 substantially frictionless. In one example, the support surface 110 is a pneumatic workbench that provides an air cushion on which the substrate floats. The support surface 110 has a plurality of holes 112 from which gas jets flow to provide an upward force to maintain the substrate at a desired height above the support surface 110. Some holes are also used to controllably exhaust gas from the air cushion that floats the substrate, thereby precisely controlling the height of the substrate locally.

[0025] The printing assembly 104 includes a dispenser assembly 114 disposed on a printing support 116. The printing support 116 is disposed relative to the substrate support 102 so that the dispenser assembly 114 is structurally positioned relative to the substrate on the substrate support 102, and the printing material is accurately applied to the substrate. The printing support 116 includes a guide rail or beam 117 that crosses the substrate support 102, so that the dispenser assembly 114 crosses the substrate support 102 and deposits the printing material to any position on the substrate from one side of the printing support 116 to the other side. In one example, the printing support 116 is attached to the base 108 and extends from the base 108, thereby stably supporting the dispenser assembly 114. Two brackets 120 extend from the base 108 (on the opposite side of the substrate support 102) to the guide rail 117 (across the substrate support 102). In one example, the bracket 120 and the guide rail 117 are made of the same material as the base 108. In one example, the bracket 120, the rail 117, the rail 117 and the base 108 are integrally formed from a single piece of granite.

[0026] The dispenser assembly 114 includes at least one print head assembly 119 and a print assembly controller 118, which includes electronic devices and / or sensors for controlling functional parameters of the print head assembly 119, such as the position, timing, duration, type of printed material, dispensing, etc. of the print head assembly 119 along the print support 116. The print head assembly 119 can be moved along the guide rail 117 of the print support 116 by operating a print carriage 122, which is coupled to the print support 116 to translate the print head assembly 119 along the guide rail 117 from one end of the guide rail 117 to the other end. In one example, the print carriage 122 is driven by a motor or servo motor. In order to simplify the drawings, power and signal conduits are omitted.

[0027] substrate ( Figure 1 104) is positioned below the printing assembly 104 by a holder assembly 106. When loading, the holder assembly 106 securely contacts the substrate and moves the substrate along the substrate support 102 to position the substrate relative to the printing assembly 104, which dispenses printing material onto the substrate in a precise manner. The holder assembly 106 is located on one side of the substrate support 102 and extends along the substrate support 102 in a first direction to translate the substrate along the first direction when printing. Figure 1 The first direction is indicated by arrow 124. The first direction 124 is sometimes referred to as the "Y direction" or the "scanning direction". The print head assembly 119 moves along a second direction under the guidance of the track 117, and the second direction is substantially transverse to the first direction. The track 117 is substantially in Figure 1 The rail 117 extends in a second direction indicated by arrow 126. The second direction 126 is sometimes referred to as the "X direction" or "cross-scan direction", and the rail 117 is referred to as an "X beam". Figure 1 The arrow 125 in the figure represents a third direction, which is substantially transverse to the first and second directions. The third direction 125 is referred to as the "Z direction". The X, Y, and Z directions are the axis directions of a coordinate system (as a reference system of the printing system 100), as shown by arrows 124, 125, and 126. In one example, the origin of the coordinate system is a fixed point, for example, related to the base 108, or the starting position of the dispenser assembly 114.

[0028] The fixture assembly 106 is disposed on a fixture assembly support 128, which in one example is a rail extending substantially along the entire length of the substrate support 102 along an edge 130 of the substrate support 102 in a first direction. In one example, the fixture assembly support 128 is attached to the base 108, stably supporting the fixture assembly 106. In one example, the fixture assembly support 128 and the base 108 are made of the same material. In one example, the fixture assembly support 128, the base 108 and the printing support 116 are integrally formed from a piece of granite. The fixture assembly support 128 is referred to as a "Y-beam". The fixture assembly 106 moves along the fixture support 128 during operation to position a firmly held substrate at any position on the substrate support 102, and the printing assembly 104, for example by operating the printing assembly controller 118, positions the print head assembly 119 to contact a precise position on the substrate to dispense printing material.

[0029] The system controller 129 receives signals sent by various sensors deployed throughout the printing system 100 and sends signals to various components of the printing system 100 to control printing. The system controller 129 is operably connected to the printing assembly controller 118 and the fixture assembly controller 131, for example, through a network, and the fixture assembly controller 131 controls the operation of the fixture assembly 106. One or more of the substrate support 102, the printing assembly 104, the fixture assembly 106, and other auxiliary systems (such as an environmental control system and a material management system) have sensors operably connected to the system controller 129, and send signals related to the status of each component to the system controller 129 during the printing operation. The system controller 129 includes data and instructions for determining the control signals sent to each controlled component of the printing system 100. In one embodiment, two or more of the system controller 129, the printing assembly controller 118, and the fixture assembly controller 131 are integrated into a single controller. In one embodiment, at least one of the system controller 129 , the printing component controller 118 , and the fixed component controller 131 is implemented as several controllers distributed in the printing system 100 and connected to each other through a network. Figure 7 An example configuration of a controller according to one embodiment is described. For the sake of brevity, reference to a “controller” in the following description refers to any one or more controllers in the printing system 100 .

[0030] In order to perform precise inkjet printing, droplets of printing material are placed in small areas on the substrate accordingly. For example, in some cases, droplets of printing material with a diameter of 5-10 μm are placed in an area of ​​10-15 μm on the substrate. This is usually done when the substrate moves along the Y direction (scanning direction) to minimize printing time. This extremely high precision is affected by many factors, such as minor defects in the size and / or position of various parts of the printing system 100, changes in these sizes with temperature, inaccuracies in the substrate, inaccuracies in the translation speed of the substrate, the dispenser assembly 114 and the fixture assembly 106, inaccuracies in the distance between the substrate and the print head assembly 119, etc. For example, if the position of the dispensing nozzle of the print head assembly 119 in the reference system of the printing system 100 cannot be accurately understood or controlled, it is difficult to control the droplets of printing material sprayed by the dispensing nozzle of the print head assembly 119, and when the substrate is in the correct position, it is difficult for the droplets of printing material to reach the target position. In some aspects, nozzle mapping is required to determine or control the position of the dispensing nozzle in the reference frame of the printing system 100. In other aspects, features of the substrate are identified and mapped into the reference frame of the printing system 100 to compensate for any deviations of the substrate.

[0031] Figure 2is a schematic top view of a printing system 200 according to one embodiment. In one embodiment, the printing system 200 includes one or more features of the printing system 100 described herein.

[0032] Printing system 200 includes a substrate support that supports a substrate in a manner similar to substrate support 102 of printing system 100. For simplicity, Figure 2 The substrate support is not shown in the figure, but the substrate 208 on the substrate support is shown. The printing system 200 also includes a print head assembly 119 having a dispensing nozzle 206. In fact, in Figure 2 The dispensing nozzle 206 may not be visible in such a plan view, but for the purpose of illustration, Figure 2 The marking of the dispensing nozzle 206 is shown in FIG. The dispensing nozzle 206 represented by a circle is shown on the upper surface of the print head assembly 119, but in fact the dispensing nozzle 206 is actually located at the same Figure 2 The nozzle surface (not visible) of the print head assembly 119 is opposite to the upper surface visible in FIG. Thus, the circle representing the dispensing nozzle 206 shows the location of the dispensing nozzle 206 on the nozzle surface opposite to the visible upper surface. The printing system 20 also includes a controller 118 and at least one imaging device 118 coupled to the controller 10.

[0033] exist Figure 2 In an example configuration, the printing system 200 includes two imaging devices, namely a first imaging device 201 and a second imaging device 202. In one example, the first imaging device 201 and the second imaging device 202 both include cameras having a set of image sensors arranged in multiple columns and rows to capture image data. Examples of image sensors include, but are not limited to, CMOS (complementary metal oxide semiconductor) sensors and CCD (charge coupled device) sensors. The first imaging device 201 has a first low resolution and a wide field of view 268. The second imaging device 202 has a second high resolution and a narrow field of view 288. The configurations of the imaging devices described are exemplary, and other configurations are also within the scope of the embodiments. In other examples, as long as the imaging device has a sufficiently wide viewing angle and / or a sufficiently high resolution, a single imaging device is sufficient for the image acquisition described herein. In other examples, imaging devices with adjustable viewing angles and / or adjustable resolutions are used.

[0034] At least one of the first imaging device 201 and the second imaging device 202 is movable relative to the substrate support and, therefore, relative to the substrate 208 on the substrate support. For example, the first imaging device 201 is mounted at the distal end of an arm 262, the proximal end of which is attached to a pivot 264. The pivot 264 is mounted on and slides along a rail 266, which is supported by one of the brackets 120, i.e., bracket 120A. The arm 262 can be telescoped (as shown by arrow 272) to adjust its length. The arm 262 can also rotate about the pivot 264 as shown by arrow 274, and the proximal end of the arm 262 can move along the rail 266 as shown by arrow 276. Similarly, the second imaging device 202 is mounted at the distal end of an arm 282, the proximal end of which is attached to a pivot 284. The pivot 284 is mounted on and slides along a rail 286, which is supported by another bracket 120, i.e., bracket 120B. The arm 282 can be telescoped to adjust its length. The described movement of the first imaging device 201 and / or the second imaging device 202 is exemplary, and other configurations are also within the scope of the embodiments.

[0035] The movement of the first imaging device 201 and / or the second imaging device 202 relative to the substrate 208 is controlled by the controller 118 through a precision positioning device such as a servo motor. Therefore, for the controller 118, the actual position of the first imaging device 201 and / or the second imaging device 202 in the reference frame of the printing system 200 is known, and the controller 118 can use the actual position to determine the actual position of one or more marks identified in the image captured by the first imaging device 201 and / or the second imaging device 202.

[0036] In one example, a first imaging device 201 having a larger field of view 268 may be used to first capture a wide-area intermediate image of the substrate 208, thereby increasing the likelihood that the intermediate image includes a mark 290 on the substrate 208. Based on the captured wide-area image, the controller 118 uses a known algorithm as described herein to identify the mark 290. The actual position of the identified mark 290 is determined based on at least the actual position of the first imaging device 201 when the wide-area image is captured. However, due to the low resolution of the first imaging device 201, in some cases, the actual position of the identified mark 290 determined based on such a low-resolution wide-area image may not be accurate enough. In this case, the second imaging device 202 having a higher resolution is moved to the position of the mark 290 in the wide-area image under the control of the controller 118 to capture another high-resolution image, so that the actual position of the mark 290 in the reference system of the printing system can be determined with high accuracy. The actual position of the mark 290 is then used to determine the actual position of one or more printing areas on the substrate 208, as described herein. The high accuracy of determining the actual position of the mark 290 helps to improve printing accuracy.

[0037] In another example, the second imaging device 202 can be moved under the control of the controller 118 so that the expected position of the mark 290 can fall within the field of view 288 of the second imaging device 202. The expected position (or predetermined position) of the mark 290 can be known from, for example, pattern data provided to the printing system 200 for a print job to print on the substrate 208. In one example, the pattern data includes an ideal position or expected position of the feature in a reference system of the printing system, and the ideal position or expected position is consistent with the ideal position or expected position information used to manufacture the previous layer (e.g., black matrix). The ideal position or expected position can be obtained from a CAD (computer-aided design) drawing of the manufacturing substrate.

[0038] If the mark 290 does exist within the narrower field of view 288 of the second imaging device 202, the mark 290 can be identified from the high-resolution image captured by the second imaging device 202, and the actual position of the mark 290 can be determined with high accuracy based on at least the actual position of the second imaging device 202 when the high-resolution image was captured, without the need to capture another image. However, if the mark 290 is not within the narrower field of view 288 of the second imaging device 202 due to substrate manufacturing errors or mark installation errors, and the mark 290 cannot be identified from the high-resolution image captured by the second imaging device 202, the first imaging device 201 with a wider field of view 268 is moved in to capture an intermediate wide-area image for identifying the mark 290, and then the actual position of the mark 290 is accurately determined by the second imaging device 202, as described above.

[0039] The order of using two imaging devices to capture multiple images of the mark described above is exemplary. In other examples, a single imaging device with an adjustable field of view and / or adjustable resolution (e.g., with a zoom function) can be used instead of multiple imaging devices to capture wide-area images and high-resolution images. In another example, a single image with both high resolution and large coverage of the substrate may be sufficient to obtain a high-precision mark without the need for multiple images, as described below with respect to Figure 3A and Figure 3B Description.

[0040] Figure 3A is a schematic side view of a printing system 300 according to one embodiment. Figure 3B In the example Figure 3A300. In one embodiment, printing system 300 includes one or more features of printing system 100 and printing system 200 described herein. In contrast to printing system 200 in which one or more imaging devices each have a set of image sensors arranged in multiple columns and multiple rows, printing system 300 includes at least one line scan imager having image sensors arranged in a row. The printing system may use the method described above. Figure 2 The imaging device described with a set of image sensors can also be used as described with respect to Figure 3A and 3B A line scan imager having a row of image sensors is described.

[0041] like Figure 3A As shown, the printing system 300 includes a substrate support 102, a print head assembly 119, and a line scan imager 303. The print head assembly 119 is movably coupled to the printing support 116 and is placed facing the substrate support 102. The line scan imager 303 is coupled to the printing support 116 or the print head assembly 119 and is also placed facing the substrate support 102. The line scan imager 303 can move along the printing support 116.

[0042] The print head assembly 119 includes a dispensing nozzle 206 extending to the substrate support 102. The print head assembly 119 and the line scan imager 303 are placed facing the print support 102 in the ejection direction 325, and the printing material will be ejected from the dispensing nozzle 206 of the print head assembly 119 to the substrate 308 of the substrate support 102 in the ejection direction 325. Here, the print head assembly 119 is coupled to the guide rail 117 through an air bearing assembly or other low friction coupling device (not shown), and a linear actuator moves the print head assembly 119 along the cross-scan direction. The linear actuator includes, for example, a motor or other drive and is coupled between the print head assembly 119 and one or both of the brackets 120A and 120B. The line scan imager 303 is coupled to the printing carriage 322 carrying the print head assembly 119, so that it can move relative to the substrate support 102 along the guide rail 117 of the print support 116 with the print head assembly 119. Line scan imager 303 is coupled to rail 313 supported by print carriage 322 so as to be movable along rail 313 by, for example, a motor or servo motor. Thus, for example, controller 118 may control line scan imager 303 to move along print support 116 by movement of print head assembly 119 along print support 116 or by movement of line scan imager 303 relative to print head assembly 119 along rail 313 or by both. In another example, line scan imager 303 is fixed to print carriage 322 and may be moved along print support 116 by movement of print carriage 322 and print head assembly 119. In another example, line scan imager 303 is coupled to print support 116 and may be movable independently of print head assembly 119. In another example, printing system 300 includes multiple line scan imagers like line scan imager 303 so that multiple images of substrate 308 are captured during a single pass of the line scan imager in the Y direction.

[0043] The line scan imager 303 is used to capture at least one image, the image including at least one mark on the substrate 308. The line scan imager 303 converts the image into data or signals and sends them to the controller 118 or another controller of the printing system 300 (e.g. Figure 1 The controller 118 receives the signal converted into image data, or the image data sent by the line scan imager 303. Based on the image data, the controller 118 determines the actual position of at least one mark, such as Figure 2The actual location of one or more printing areas of substrate 308 is then determined based on the actual location of the markings, as described herein. The determination of the printing area is a process for controlling printing system 300 to perform high-precision printing. Another optional process facilitates nozzle mapping. With respect to nozzle mapping, printing system 300 includes an imaging device 302 oriented in a Z direction opposite to jetting direction 325 for capturing at least one image including a plurality of markings on a bottom surface (or nozzle surface) 329 of printhead assembly 119. The captured image is sent to controller 118 or another controller of printing system 300, such as Figure 3A As shown, the controller 118 is connected to the imaging device 302. For example, the controller 118 identifies the mark on the nozzle surface 329 of the printing nozzle assembly 119 from the image sent by the imaging device 302, and maps the position of the dispensing nozzle 206 to the reference system of the printing system 300. According to the mapped position (or actual position) of one or more printing areas of the substrate 308 and the mapped position of the dispensing nozzle 206 in the same reference system, the printing material in the dispensing nozzle 206 is controlled to be ejected to one or more printing areas of the substrate 308. Because the mapped position of the dispensing nozzle 206 and one or more printing areas reflects the actual position of the dispensing nozzle 206 and one or more printing areas with high accuracy, the printing accuracy is improved. In an example configuration, the imaging device 302 for nozzle mapping is a line scanning imager, which collects an image including the nozzle surface 329 of the printing nozzle assembly 119 while the printing nozzle assembly 119 passes through the imaging device 302 in the scanning direction (X direction). In at least one embodiment, the imaging device 302 is omitted.

[0044] Figure 3B In the example Figure 3A 308 of the printing system 300. More specifically, for comparison, Figure 3B The substrates 308 are shown placed side by side (as shown in FIG. Figure 3A The plan view of the spray direction 325 in FIG. 300 is similar to the plan view of the line scan imager 303 (such as from the Figure 3A A combined view of a planar top view of the bottom surface (looking upward in the Z direction).

[0045] The line scanner imager 303 includes a plurality of image sensors 332. Figure 3BIn an example configuration, all of the image sensors 332 of the line scanner imager 303 are arranged in a row, such as line 331, along a cross-scan direction (X direction). In another embodiment (not shown), the image sensors 332 of the line scan imager 303 are arranged in more than one row. For example, the image sensors 332 in the first row are used as primary image sensors to collect image data, while the image sensors 332 in the second row can be used as redundant or secondary sensors to provide image data in the event of a failure of one or more primary image sensors, or as additional sensors to improve the signal-to-noise ratio of the image data. The image sensors 332 are optoelectronic devices that collect light reflected from the substrate 308 toward the line scan imager 303 and record electrical signals based on the collected light. As the substrate 308 moves below and relative to the line scan imager 303 in the scan direction (Y direction), the image sensors 332 collect an image including one or more marks on the substrate 308 as described herein. In this regard, the image acquisition performed by the line scan imager 303 is similar to the image acquisition performed by a copier or scanner using a similar linear light sensor arrangement. In order to acquire images including marks or features with sizes in the range of several microns, such as 5-10 microns, the image sensor 332 is configured to provide a high resolution of, for example, about 0.1 microns. Examples of image sensors include, but are not limited to, CMOS (complementary metal oxide semiconductor) sensors and CCD (charge coupled device) sensors.

[0046] To acquire an image using the line scan imager 303, the line scan imager 303 is moved in the X direction under the control of the controller 118 to a position where the mark to be acquired may fall within the field of view of the line scan imager 303. The line scan imager 303 is then temporarily fixed in the X direction relative to the substrate support, and the substrate support moves the substrate 308 in the Y direction for image acquisition to acquire the mark. For example, during the movement of the substrate 308 in the Y direction, the line scan imager 303 passes through the area of ​​the substrate 308 between the lines 373, 374. The width of this area, or the distance between the lines 373, 374, corresponds to the length of the line 331 of the image sensor 332 in the X direction. The controller 118 controls the line scan imager 303 to acquire an image of the area 383, 384, 385 (hereinafter referred to as image 383, 384, 385) between the lines 373, 374. Image 383 is acquired at the position where the mark 520 is expected to be found. Similarly, image 384 is captured at the locations where marks 522 and 560 are expected to be found, and image 385 is captured at the location where mark 562 is expected to be found. The expected locations of the marks on substrate 308 are contained in the pattern data provided to the printing system for printing on substrate 308. The pattern data includes at least the printing data of the pattern to be printed on substrate 308 as coordinates in the reference system of the printing system. Before capturing the images, the controller 118 controls the movement of the line scan imager 303 in the X direction based on the pattern data so that the expected locations of the marks to be imaged fall within the field of view of the line scan imager 303, for example, the expected locations of marks 520, 542, 560, 562 fall within the area between lines 373, 374. In at least one embodiment, some of images 383, 384, 385 are combined into one image. For example, marks 520 and 522 may be contained in one image extending along the Y direction, and marks 560 and 562 may be contained in another image extending along the Y direction. The images captured by the line scan imager 303 in the printing system 300 are used in a manner similar to the way the images captured by the first imaging device 201 and / or the second imaging device 202 of the printing system 200 are used. However, depending on the size or length of the line 331 of the image sensor 332 in the X direction and / or the length of the captured image / area in the Y direction, the line scan imager 303 can capture high-resolution images covering a wide area. Therefore, when using the line scan imager 303, multiple image captures can be avoided, as described in the examples with respect to the first imaging device 201 and / or the second imaging device 202.

[0047] Now describe Figure 3B308, which will be used as an example substrate, is mapped into a reference frame of the printing system according to some embodiments using one or more imaging devices as described with respect to printing system 200 and / or one or more line scan imagers as described with respect to printing system 300. In one example, substrate 308 is a glass substrate, but other materials such as plastic or ceramic may also be used with the various printers described herein.

[0048] The substrate 308 includes at least one substrate alignment feature and a plurality of print area alignment features. An alignment feature may be any feature having one or more known characteristics, which refers to at least one of the position or orientation of an object, which may be captured in image data and may be identified from the captured image data. The substrate alignment feature indicates at least one of the position or orientation of the substrate. The print area feature refers to at least one of the position or orientation of at least one print area on the substrate. For example, the alignment feature may be a mark, sometimes referred to as a "reference mark," having one or more known characteristics, such as pattern, orientation, size, and position on the substrate 308. The mark is attached (e.g., by an adhesive), or etched or machined, or printed or coated on the substrate 308. Other ways of providing marks on the substrate may be used. Marks of any number and / or shape and / or material and / or orientation may be used. Any mark may include text, a barcode, a company name, and / or a logo. The greater the number of marks and / or the more complex the shape of the marks, the greater the accuracy of the position of the print area determined using the marks. Alignment features may also include features inherent to or included in the substrate 308. In one example, one or more edges and / or one or more corners of substrate 308 can be used as alignment features. In yet another example, features included on substrate 308 in previous processing can be used as alignment features. Examples of such features include pixel wells or sub-pixel wells in black matrix material, or other pixel or area definition where the printed material will be deposited. For simplicity only, indicia are used as alignment features in the following description of exemplary embodiments.

[0049] exist Figure 3BIn an example configuration, the substrate 308 includes one or more substrate marks 501, 511, 521, 531 arranged at one or more corners of the substrate 308 as substrate alignment features. Each substrate mark 501, 511, 521, 531 is in the shape of a cross, and its position and direction can be known from the pattern data. The substrate marks 501, 511, 521, 531 together accurately indicate the position of the substrate 308 in the reference system of the printing system. The shape and / or size and / or number and / or orientation and / or relative position within the substrate of the substrate marks 501, 511, 521, 531 are merely exemplary. Other configurations are also within the scope of various embodiments. For example, assuming that the substrate mark 501 has a known spatial relationship with the corresponding corner 301 of the substrate 308, then a single substrate, such as the substrate mark 501, may be sufficient to indicate the position of the substrate 308. In another example, the edge or corner of the substrate 308 can be used as a substrate mark. While in some cases only one substrate mark may be sufficient, when more than one substrate mark is provided on the substrate 308, the accuracy of material deposition may be increased.

[0050] In addition to the substrate mark, the substrate 308 also includes a plurality of printing area marks for identifying the plurality of printing areas and mapping the plurality of printing areas to the reference system of the printing system. For simplicity, the printing area marks are referred to as "marks" in the following description. Figure 3B In an example configuration, the substrate 308 includes seven printing areas sp1 to sp7, each of which corresponds to, for example, a display panel to be manufactured. In order to identify the location of the printing area, each printing area of ​​the substrate 308 includes one or more markings. Specifically, each of the printing areas sp1 to sp5 is identified by a set or group of four markings at its corners, while the printing areas sp6 and sp7 share a common set of four markings 590, 592, 594, 596 at the corners of their areas. Figure 3B In the figure, for the sake of simplicity, some reference numerals of the marks are omitted. Marks 510, 512, 514, 516 on the substrate 308 are used to identify the printing area sp1, marks 520, 522, 524, 526 on the substrate 308 are used to identify the printing area sp3, and marks 560, 562, 564, 566 on the substrate 308 are used to identify the printing area sp4.

[0051] In some other methods, a limited set of marks is provided to define the entire substrate, and no separate set of marks is provided for each printing area. For example, some methods may only include substrate marks 501, 511, 521, 531 on the substrate 308, and then use the substrate marks 501, 511, 521, 531 to calculate the position information of the printing area based on the layout design information of the substrate and assuming that the printing area is perfectly arranged on the substrate as expected. Such methods may not be able to solve and remedy the situation where the printing area cannot be arranged as expected due to, for example, substrate manufacturing errors. For example, Figure 3B As shown, the printing area sp1 has a placement error compared to other printing areas. The placement error can include XY offset, rotation, scaling, skew and keystone (imaging verticality) errors. The calculated position of the printing area is inaccurate, especially these printing areas with placement errors, which affects the printing accuracy of other methods.

[0052] Figure 4 is a flow chart of a printing method 400 according to one embodiment. Figures 5A-5D is based on Figure 4 A schematic plan view of a substrate 308 or a portion of a substrate 308 processed by various operations of the printing method is shown. The printing method 400 may be performed by or under the control of at least one controller described herein in any of the printing systems 100, 200, and 300. In the following description, the printing method 400 is performed by or under the control of the controller 118.

[0053] In operation 405, at least one image of a substrate loaded in the printing system is acquired. For example, the controller 118 acquires at least one image of a substrate 308 loaded in the printing system 200 or 300 from the first imaging device 201 and / or the second imaging device 202 of the printing system 200 or the line scan imager 303 of the printing system 300, respectively. The at least one image is acquired at the expected position of the target mark. In the following description, the line scan imager 303 is used for image acquisition.

[0054] Figure 5A 5 is a schematic plan view of a portion of substrate 308 where substrate mark 501 is located according to pattern data. An image 506 of the portion of substrate 308 is collected and sent as a signal or image data to controller 118 for mark recognition. According to the pattern data of substrate 308, such as Figure 5AThe substrate mark 501 in its intended form shown by the dashed line has a cross shape. The cross is formed by the vertical element 502 and the horizontal element 503 intersecting each other at the center point 504, and the vertical element 502 and the horizontal element 503 are oriented in the Y direction and the X direction respectively. From the pattern data, it can be seen that the XY coordinate system of the center point 504 in the reference system of the printing system is the expected position 504A of the substrate mark 501. Figure 5A The dashed lines in FIG. 5 are for illustration purposes and are not captured in the image 506. The image 506 is captured by moving the line scan imager 303 under the control of the controller 118 to a position where the substrate mark 501 may fall within the field of view of the line scan imager 303 at its expected position, and then capturing the image 506. The controller 118 acquires or generates data representing the captured image 506 from the transmission of the line scan imager 303.

[0055] In operation 415, an actual position of a first alignment feature on the substrate is determined based on the at least one acquired image. Figure 5A , the controller 118 determines the actual location of the substrate mark 501 based on the data representing the image 506. To this end, the controller 118 performs a mark recognition process to recognize the substrate mark 501 from the image data using known characteristics of the substrate mark 501 included in the pattern data stored in the controller 118 and / or accessible by the controller 118. Image processing algorithms and / or software and / or programs for recognizing objects based on known characteristics of the objects, such as pattern, position, size and / or orientation, are known in the field of image processing and are not described in detail herein.

[0056] When the substrate mark 501 cannot be identified from the captured image 506, the controller 118 controls the line scan imager 303 to retake the image. In one example, retaking the image involves repositioning the line scan imager 303 to a new position along the X direction to better correspond to the expected position 504A of the substrate mark 501. In another example, retaking the image involves adjusting the resolution and / or field of view of the line scan imager 303 to image a wider area of ​​the substrate 308. When an imaging device, such as a camera, is used for image capture, as described in detail in detail in the embodiment of the present invention, the line scan imager 303 may be used to capture the substrate mark 501. Figure 2 Then, the controller 118 performs the mark recognition process again to recognize the substrate mark 501 from the recaptured image.

[0057] In at least one embodiment, it may not be necessary to capture the entire mark. Instead, when a portion of the mark is sufficient to determine the position of the mark, capturing an image including the portion is sufficient to define the entire substrate. Therefore, as used herein, "one or more images including one or more marks" or similar expressions do not require that the entire mark be captured from the image; rather, it is sufficient to capture a portion that allows the mark to be identified from the image of the captured portion for subsequent determination of the mark's position.

[0058] Identifying a mark means that the controller has determined that an image (either a single image or a composite image) contains the mark. When the controller identifies a mark, a process is triggered to map the mark into the reference system of the printing system by determining the actual position of the mark in the reference system of the printing system. As a result of the mark identification and mapping process, the identified substrate mark 501 is found at the actual position 504B in the reference system of the printing system, whether or not the image is re-photographed, as shown in FIG. Figure 5A , as shown by the solid line in . The controller 118 can determine the actual position of the identified substrate mark 501 based on the known actual position of the image captured by the line scan imager 303. The XY coordinate system of the actual position 504B is offset from the XY coordinate system of the expected position 504A. The orientation of the identified substrate mark 501 may also be different from its expected orientation, as shown by the angle α between the vertical element 502 of the identified substrate mark 501 at the actual position 504B and the Y direction. In one example, the image acquisition and mark recognition processing described is performed to obtain more than one substrate mark, such as substrate marks 501, 511, 521, 531 on the substrate 308. In another example, the actual position of one or more other substrate marks 511, 521, 531 is calculated based on the determined actual position of the substrate mark 501 and the pattern data including the known relationship between the substrate marks. The controller 118 utilizes the determined actual position and / or orientation and / or other actual characteristics of the one or more substrate marks and based on the known relationship between the one or more substrate marks in the pattern data and the substrate 308 to determine the actual position and / or orientation of the substrate 308. The controller 118 may utilize the determined actual position and / or orientation of the substrate 308 to fundamentally adjust the substrate 308 and / or correct the print data of the pattern to be printed on the substrate 308.

[0059] In operation 425, expected positions of a plurality of second alignment features on the substrate are determined based on the actual positions of the first alignment features. For example, the controller 118 calculates the expected positions of the print area marks using the actual positions and / or orientations of the one or more substrate marks 501, 511, 521, 531 determined in operation 415 and based on a known relationship between the one or more substrate marks and the print area marks in the pattern data. Bilinear interpolation is an exemplary method of calculating the expected positions of the print area marks, which includes one or more interpolation operations, such as translation, rotation, tilt, and scaling.

[0060] Figure 5B 4 shows a schematic plan view of the substrate 308 as determined by the controller 118 as a result of operation 425. Figure 5B , the actual positions of substrate marks 501, 511, 521, 531 are determined by operation 415 and are shown in solid lines at their actual positions. Print area marks have not yet been identified or mapped and are shown in dashed lines at their respective intended positions. It should be noted that in this example, it is still desirable to Figure 3B The marks 510 , 512 , 514 , 516 corresponding to the offset printing area sp1 are close to the ideal positions or expected positions defined by the pattern data.

[0061] In operation 435, the actual position of the second alignment feature is determined based on the at least one image and the expected position of the second alignment feature. For example, the controller 118 performs a mark recognition process on an area of ​​the image acquired in operation 405 in which the expected position determined in operation 425 represents a possible location of the print area mark. This is possible in the following case, that is, in operation 405, for example, the image acquired by the line scan imager 303 is a high-resolution image covering a large area of ​​the substrate 308, wherein the substrate 308 has one or more substrate marks and one or more print area marks. It can be seen that the acquired image already contains one or more print area marks, and the same image can be processed without retaking the image. In the case where the acquired image does not cover all print area marks, other images are acquired in a manner similar to operation 405.

[0062] The actual positions of the identified printing area marks are determined from the captured image data in a manner similar to operation 415. All printing area marks representing printing areas can be identified, and their actual positions can be determined from the captured image. For example, all printing area marks 520, 522, 524, 526 representing printing area sp3 can be identified, and their actual positions can be determined from the captured image. This configuration provides high-precision printing area clarity. However, in some cases, the actual position of at least one printing area mark representing a printing area can be calculated based on the actual positions of other printing area marks representing the same printing area. For example, some printing area marks 510, 512, 514 representing printing area sp1 are identified, and their actual positions are determined based on the captured image; however, the actual position of the remaining printing area mark 516 representing the same printing area sp1 is calculated based on the actual positions of the other printing area marks 510, 512, 514 that have been determined. This configuration sacrifices some accuracy in printing area clarity in order to speed up processing. As Figure 3B As shown, when the printing area sp1 is obviously misaligned, this sacrifice of accuracy may affect the printing precision and ultimately the quality of the printed product.

[0063] Figure 5C 4 shows a schematic plan view of the substrate 308 as determined by the controller 118 as a result of operation 435. Figure 5C , after operations 415 and 435, all substrate marks and print area marks have been mapped into the reference system of the printing system and are shown in solid lines at their actual locations. Since the printing area represented by the print area mark has not yet been obtained, it is shown in dashed lines. In other words, the coordinates of each printing position in each printing area in the reference system of the printing system have not yet been determined. The controller 118 has now determined and may have quantified and / or marked that the printing area sp1 is not in its expected position ( Figure 5B ), but it is actually placed in the wrong place ( Figure 5C ). As described herein, such detected placement error of the printing area sp1 allows the controller 118 to make corrections to improve printing accuracy. In at least one embodiment, not all printing area marks are processed simultaneously. For example, the printing area marks corresponding to the printing area sp1 and the printing area sp2 are processed first so that printing can be performed in the printing area sp1 and the printing area sp2. While the printing operation is being performed in the printing area sp1 and the printing area sp2, the printing area marks corresponding to the next printing area to be printed, i.e., the printing area sp3 and the printing area sp4, are mapped, and so on. This configuration reduces the processing time and printing time of the entire substrate 308 by parallel operation.

[0064] In operation 445, based on the actual position of the second alignment feature, the target position of multiple printing areas on the substrate is determined. The "target position" of the printing area or pixel used in this article is the actual position of the printing area or pixel in the reference system of the printing system, and the position of the printing head assembly that controls the printing system to deposit the printing material. The pattern data may include a coordinate diagram that presents the expected position of the mark and at least the corners of the corresponding printing area, for example, as an XY coordinate system in the reference system of the printing system or substrate. Taking the printing area sp3 as an example, once the controller 118 maps the marks 520, 522, 524 and 526, the actual positions of the marks 520, 522, 524 and 526 are compared with their known / expected positions in the pattern data. By comparison, the controller 118 obtains the conversion relationship between the positions of the marks 520, 522, 524 and 526 determined from the captured image and their known / expected positions in the pattern data. The controller 118 uses the obtained relationship and the expected positions of the corresponding corners 540, 542, 544 and 546 of the printing area sp3 in the pattern data to determine the actual positions of the corners 540, 542, 544 and 546 of the printing area sp3 in the reference system of the printing system.

[0065] Then, the controller 118 determines the actual positions of all pixels to be printed in the printing area sp3 according to the actual positions of the corners 540, 542, 544, and 546. An example method for determining the actual positions of the pixels according to the corners is bilinear interpolation, including one or more interpolation operations, such as translation, rotation, tilt, and scaling. Alternatively, in a thin film encapsulation (TFE) application, in which the film is to be deposited on the printing area sp3 instead of printing individual pixels, the controller 118 determines the actual position of the boundary of the printing area sp3 according to the actual positions of the corners 540, 542, 544, and 546. The determination of the actual position of the mark, the printing area corner, the pixel or the boundary in the reference system of the printing system is also referred to as mapping in this article. In some embodiments, the controller 118 performs nozzle mapping in a similar manner to determine the actual position of the dispensing nozzle of the printing nozzle assembly 119 based on the nozzle surface mark (not shown) contained in the nozzle surface 329 and one or more images taken by the imaging device 302 containing the nozzle surface mark.

[0066] Figure 5D 4 shows a schematic plan view of the substrate 308 determined by the controller 118 as a result of operation 445. Figure 5D In the example, all substrate marks, print area marks, and print areas have been mapped in operations 415, 435, 445 and are shown in solid lines at their actual or target locations. This is just one example. As described above, one or more print areas may be processed while a print operation is being performed in one or more other print areas.

[0067] Although in the above description, the identification and mapping of printing areas involves collecting and processing marks for each printing area separately, the present disclosure is not limited thereto. For example, the clarity of the printing area may involve collecting and processing a set of marks 590, 592, 594, 596 common to several printing areas, such as Figure 5D When all common marks 590, 592, 594, 596 have been acquired and identified, the actual positions of the pixels or boundaries of the printing areas sp6 and sp7 are determined, for example, by interpolation, based on the actual positions of the common marks 590, 592, 594, 596 and based on the pattern data indicating the expected positions or the relationships of the printing areas sp6 and sp7 relative to the marks 590, 592, 594, 596.

[0068] In operation 455, based on the established target position of the printing area, the printing material is controlled to be ejected onto the substrate in the plurality of printing areas. For example, based on the actual position of the pixel point or boundary of the printing area sp3 in the reference system of the printing system and / or the actual position of the dispensing nozzle of the printing nozzle assembly 119 in the reference system of the printing system, the controller 118 controls the printing material to be ejected from the dispensing nozzle of the printing nozzle assembly 119 to the printing area sp3 of the substrate 308. In one embodiment, the printing material ejection control includes physical adjustment of the substrate 308 and / or the printing nozzle assembly 119, and / or logical modification of the printing data for generating a control signal of the dispensing nozzle to eject the printing material. Since the determined actual position of the dispensing nozzle and / or the printing area sp3 accurately reflects the real physical position of the dispensing nozzle and the printing area sp3, the printing accuracy is improved.

[0069] Specifically, the actual position of the dispensing nozzle and the printing area are in the same reference frame of the printing system and are used by the controller 118 to control when and / or which dispensing nozzles to eject the printing material based on the pattern data, which includes coordinates in the reference frame of the printing data or substrate. For example, if the position of the printing nozzle is found to be different from its expected position by a distance d, then the ink droplets ejected according to the existing printing plan will arrive at a position different from its target position t by a distance d. If the distance d has an x-component (the distance in the x direction) d x , the print head assembly can be adjusted -d x If the printing nozzle is at an average distance in the X direction deviates from its intended position, the printed component can be adjusted to compensate. If the distance d has a y-component d y, then the global delay trigger dy / v can be used to adjust the printing plan, where v is the translation speed of the substrate in the Y direction, and the average distance of the y-vector is Thereby, a printed product with high printing accuracy can be obtained.

[0070] In one embodiment, printed products manufactured by the printing method include, but are not limited to, solar panels and flat panel displays, such as organic light emitting diode (OLED) displays.

[0071] Fig. 6A is a flow chart of a printing method 600 according to one embodiment. Figure 6B is based on Fig. 6A FIG. 6 is a schematic plan view of a printing area sp3 on a substrate 308 processed by the printing method 600. For ease of explanation, the printed area sp3 is enlarged. Figure 6B The printing method 600 may be performed by or under the control of at least one controller described herein in any of the printing systems 100, 200, and 300. In the following description, the printing method 600 is performed by or under the control of the controller 118. In one embodiment, the printing method 600 includes one or more features of the printing method 400 described herein.

[0072] In operation 605, at least one image including the alignment features on the substrate is acquired. For example, in a manner similar to operation 405 in the printing method 400, the controller 118 acquires at least one image including one or more marks from the first imaging device 201 and / or the second imaging device 202 of the printing system 200 or the line scan imager 303 of the printing system 300.

[0073] In operation 615, the actual positions of the plurality of alignment features in the reference system of the printing system are determined based on the at least one image. For example, the controller 118 determines the actual positions of the marks 520, 522, 524, 526 representing the printing area sp3 based on the acquired images in a manner similar to operations 415 and / or 435 in the printing method 400.

[0074] In operation 625, the target position of the pixel point at the corner of the printing area on the substrate is determined based on the actual position of the alignment feature. For example, the controller 118 compares the actual position of the mark 520, 522, 524, 526 with its predetermined position in the pattern data, thereby obtaining a relationship or conversion function between the actual position of the mark 520, 522, 524, 526 (e.g., determined based on the collected image) and its predetermined position in the pattern data. The controller 118 uses the obtained conversion function and the predetermined position of the corner 540, 542, 544, 546 in the pattern data to determine the actual position of the corner 540, 542, 544, 546.

[0075] In operation 635, the target position of the pixel point on the edge of the printing area is determined based on the target position of the pixel point at the corner of the printing area. Figure 6B As shown, the controller 118 determines the first side 620 of the printing area sp3 according to the actual positions of the corners 540 and 546, determines the second side 630 of the printing area sp3 according to the actual positions of the corners 540 and 542, determines the third side 640 of the printing area sp3 according to the actual positions of the corners 542 and 544, and determines the fourth side 650 of the printing area sp3 according to the actual positions of the corners 544 and 546.

[0076] For TFE applications, the controller 118 may now proceed to operation 655 to control the print head assembly to deposit a thin film on the print area sp3 within the boundaries defined by the determined edges 620, 630, 640, 650 of the print area sp3.

[0077] For printing at a single pixel point of the printing area sp3, the controller 118 determines the actual positions of the pixels 622 and 624 on the determined first side 620 based on the number of pixels in each row of the printing area sp3 in the X direction in the image data (e.g., the pixels are evenly distributed along the first side 620). Similarly, the controller 118 determines the actual positions of the pixels 642 and 644 on the determined third side 640 based on the same number of pixels in each row.

[0078] In operation 645, the target position of the pixel point in the printing area is determined based on the target position of the pixel point along the edge of the printing area. Figure 6BAs shown, the controller 118 determines the actual position of the pixel points 631 and 671 on the determined second side 630 based on the number of pixels in each column of the printing area sp3 in the Y direction in the pattern data. Similarly, the controller 118 determines the actual position of the pixel points 636 and 676 on the determined fourth side 650 based on the same number of pixels in each column. For the pixel points inside the printing area sp3, the controller 118 first determines the column 660 of the pixel points based on the corresponding determined pixel points 622 and 642 on the corresponding first and third sides 620 and 640, and then the controller 118 determines the actual position of the pixel points 632 and 672 on the determined column 660 based on the number of pixels in each column. Similarly, the controller 118 determines the column 670 of the pixel points based on the corresponding determined pixel points 624 and 644 on the corresponding first and third sides 620 and 640, and then determines the actual position of the pixel points 634 and 674 on the determined column 670 based on the number of pixels in each column. The above process is repeated until the actual positions of all pixels in the printing area sp3 are determined.

[0079] In at least one embodiment, operations 625 , 635 , 645 of printing method 600 are performed in operation 445 of printing method 400 to determine a target position of a print area on a substrate based on an actual position of a print area mark.

[0080] In operation 655 , based on the target position of the pixel point in the printing area, the printing material is controlled to be ejected from the dispensing nozzle of the print head assembly onto the substrate in the printing area. For example, the controller 118 controls the ejection of the printing material in a manner similar to operation 455 in the printing method 400 .

[0081] Figure 7 is a flow chart of a printing method 700 according to one embodiment. The printing method 700 may be performed in any of the printing systems 100, 200, and 300 by or under the control of at least one controller described herein. In the following description, the printing method 700 is performed by or under the control of the controller 118. In one embodiment, the printing method 700 includes one or more features of the printing methods 400, 600 described herein.

[0082] In operation 705, at least one imaging device is controlled to acquire a first image of a plurality of first alignment features on the substrate. For example, the controller 118 controls the first imaging device 201 and / or the second imaging device 202 to acquire one or more first images including the substrate marks 501, 511, 521, 531 on the substrate 308 in a manner similar to operation 405 in the printing method 400 described above.

[0083] In operation 715, based on the first image, the actual position of the first alignment feature in the reference system of the printing system is determined. For example, the controller 118 performs a mark recognition process on the acquired first image to recognize substrate marks 501, 511, 521, 531 from the acquired first image, and then determines the actual position of the recognized substrate marks in a manner similar to operation 415 in the printing method 400. In some cases, multiple image acquisitions are performed by multiple imaging devices, such as with respect to Figure 2 Description.

[0084] In operation 725 , the expected positions of the plurality of second alignment features are determined based on the actual positions of the plurality of first alignment features. For example, the controller 118 determines the expected positions of the print zone marks based on the actual positions of the substrate marks in a manner similar to operation 425 in the printing method 400 .

[0085] In operation 727, based on the expected position of the second alignment feature, the relative position of the at least one imaging device and the substrate support supporting the substrate is controlled so as to image the second alignment feature using the at least one imaging device. For example, the controller 118 performs control to reposition the first imaging device 201 and / or the second imaging device 202 so that the one or more expected positions of the one or more printing area marks determined in operation 725 can fall within the field of view of the first imaging device and / or the second imaging device 202.

[0086] In operation 729, the at least one imaging device is controlled to capture a second image of the second alignment feature. For example, after repositioning in operation 727, the controller 118 controls the first imaging device 201 and / or the second imaging device 202 to capture one or more second images including the expected location of the one or more printed area marks.

[0087] In operation 735, based on the second image, the actual position of the second alignment feature in the reference frame of the printing system is determined. For example, the controller 118 performs a mark recognition process on the second image acquired in operation 729 to identify one or more print area marks from the acquired second image, and then determines the actual position of the identified print area marks in a manner similar to operation 715. In some cases, multiple image acquisitions are performed by multiple imaging devices, such as with respect to Figure 2 Description.

[0088] In the event that the field of view of the first imaging device 201 and / or the second imaging device 202 is not wide enough to capture one or more print area marks and / or substrate marks in the first image, at least one imaging device may be repositioned according to operation 727 and subsequent images may be captured according to operation 729. Figure 4The images captured by a line scan imager such as line scan imager 303 can cover a sufficiently wide area of ​​substrate 308 to capture target marks, and a separate image capture process can be avoided.

[0089] In operation 745, a target position of a print area corresponding to the second alignment feature set is determined based on the actual position of the second alignment feature. For example, the controller 118 determines the target position of the print area based on the actual position of the corresponding set of print area marks in a manner similar to operation 445 and / or operations 625, 635, 645.

[0090] In operation 755 , the printing material is controlled to be ejected from the dispensing nozzle of the print head assembly onto the substrate of the printing area based on the target position of the area printing. For example, the controller 118 controls the ejection of the printing material in a manner similar to operation 455 .

[0091] In some cases, a line scan imager may be used to calibrate the position of the substrate on the substrate support 102 ( Figure 1 ). Thus, instead of performing the above-described operation 755, or in addition to performing the above-described operation 755, a repositioning operation may be performed to improve the position of the substrate on the substrate support. In one example, the actual position of the substrate mark may be compared with the desired position of the substrate mark based on the pattern data of the substrate, and a deviation parameter may be determined using any controller or processor described herein. The deviation parameter may be determined in a variety of ways. In one example, the deviation of each substrate mark from its designed position may be determined, and the deviation parameter may be set to a maximum deviation. In another example, the deviation parameter may be set to an average deviation. In another example, the deviation parameter may be set to a deviation of a predetermined substrate mark.

[0092] The deviation parameter is then compared to the tolerance to determine whether the substrate needs to be repositioned. Any controller or processor described herein can perform the comparison. If the substrate needs to be repositioned, the printing system is controlled to perform the standard substrate positioning procedure again. This process can be repeated until the deviation parameter is within the tolerance, at which time the above-mentioned operation 755 can be performed.

[0093] The described methods include example operations, but they are not necessarily performed in the order shown. Operations may be appropriately added, replaced, changed in order, and / or deleted within the spirit and scope of the embodiments of the present disclosure. Embodiments formed by combinations of different features and / or different embodiments are also within the scope of the present disclosure and are apparent to those of ordinary skill in the art who have read the present disclosure.

[0094] Figure 8 is a block diagram of a controller according to one embodiment. In one embodiment, by Figure 8One or more controllers 800 are implemented Figure 1-7 One or more devices and / or systems and / or operations described in.

[0095] The controller 800 includes a hardware processor 802, a storage device 804 including at least one non-transitory computer-readable storage medium, a bus 808, an I / O (input / output) interface 810, and a network interface 812. The processor 802 is coupled to the storage device 804, the I / O interface 810, and the network interface 812 via the bus 808. The network interface 812 can be connected to a network 814 so that the processor 802 and the storage device 804 can communicate with other devices via the network 814. The processor 802 is used to execute computer program instructions encoded in the storage device 804 and / or access data stored in the storage device 804, so that the controller 800 performs operations related to Figure 1-7 One or more functions and / or operations described.

[0096] Processor 802 includes one or more of a central processing unit (CPU), a multiprocessor, a distributed processing system, an application specific integrated circuit (ASIC), and / or a suitable hardware processing unit.

[0097] The storage device 804 includes one or more of an electronic, magnetic, optical, electromagnetic, infrared, and / or semiconductor system (or device or apparatus) for non-temporarily storing instructions and / or data. For example, the storage device 804 includes a semiconductor or solid-state memory, a magnetic tape, a removable computer disk, a random access memory (RAM), a read-only memory (ROM), a hard disk, and / or an optical disk. As examples of optical disks, the storage device 804 includes a compact disk-read only memory (CD-ROM), a compact disk-read / write (CD-R / W), and / or a digital versatile disk (DVD).

[0098] The I / O interface 810 is a circuit that can be connected to an external circuit. For example, the I / O interface 810 includes one or more of a keyboard, a key, a mouse, a trackball, a touchpad, a cursor direction key, a card reader, a communication port, a display, a signal light, a printer, and / or an audio device, and is used to communicate information with the processor 802. In one example, the I / O interface 810 is omitted.

[0099] The network interface 812 is a circuit that allows the controller 800 to communicate with the network 814, and one or more other controllers and / or image acquisition / processing devices are connected to the network 814. For example, the network interface 812 includes one or more wireless network interfaces such as Bluetooth, WIFI, WIMAX, GPRS, WCDMA, etc.; or a wired network interface, such as ETHERNET, USB, or IEEE-1394. In one example, the network interface 812 is omitted.

[0100] By executing on Figure 1-7 Some or all of the functions and / or operations described above, the controller 800 can implement Figure 1-7 One or more of the advantages and / or effects described.

[0101] If the layout of the substrate is known in advance so that the printing system can be configured to utilize the substrate layout, the alignment features on the substrate can be quickly located. If a series of substrates with similar or identical layouts are to be processed, the printing system can be configured to quickly locate the alignment features on consecutive substrates by positioning and activating the camera to focus on the likely location of the alignment features.

[0102] In one instance, a substrate has six panels defined across the width of the substrate. The panels can define a single display device to be formed on the substrate or a group of display devices to be formed on the substrate. The supplementary figures attached in the Appendix to this application summarize the configuration of a camera for a printing system to quickly acquire and locate alignment marks for such a substrate. Here, the substrate has one or more first alignment features, sometimes also referred to as fiducial marks, and each panel on the substrate is defined using one or more second alignment features. Because it is known in advance that the substrate has six panels of substantially the same size and shape evenly spaced across the width of the substrate, the camera or line imager can be positioned along the printing support, as described herein, and actuated to locate the first alignment feature and the second alignment feature.

[0103] In this case, a first camera system including one or more cameras captures a wide image of one or more areas of the substrate. The substrate is scanned from an input side of the printing system to an output side of the printing system for a first scan, and the first camera system captures a first image or multiple first images of the substrate during the first scan. The first scan captures images of at least two first alignment features and may also capture one or more second alignment features. The first scan may capture an image of the entire substrate, or the first scan may capture only areas where the first alignment features are expected to be found on the substrate. Therefore, a single first image may include more than one first alignment feature captured and logically combined in multiple images, or the first scan may capture multiple first images.

[0104] The substrate is typically positioned at the input end of a printing system for processing. The substrate rests on a positioning feature, such as a physical post or bank, which initializes the position of the substrate. A substrate positioning system is securely connected to the substrate for further positioning. The substrate typically has a first end and a second end that are opposite and a first side and a second side that are opposite. The first end of the substrate passes through each imaging system and then the second end passes through each imaging system. As described above, the first image or multiple first images include at least two first alignment features and may include more than two first alignment features. If the two first alignment features are located at the first end of the substrate, then the first scan may only be a partial scan of the substrate, imaging only the first alignment features that are expected to be found near the first end.

[0105] In one case, the first alignment features are expected to be located near the corners of the substrate, so wide area cameras can be located on both sides of the substrate processing surface of the printing system to capture wide area images of the substrate near these expected locations. Each wide area camera has a field of view large enough to eliminate errors that may occur in locating the first alignment features, so the wide area camera will almost certainly capture the first image (or images). In one embodiment, the positioning error of the first alignment features is about 2 mm, and a wide area camera with a field of view of 10-13 mm is used.

[0106] The first image (or images) is analyzed using image processing software to identify alignment features therein. The image processing software searches for the first alignment feature based on a local search informed by an expected position of the first alignment feature. The expected position is defined as a coordinate in a first coordinate system defined by the printing system, as described elsewhere herein, and is based on a predefined layout of the substrate, the layout including the coordinates of the alignment feature in a second coordinate system defined by the substrate. When the substrate is loaded into the input side of the printing system, a mathematical transformation of the second coordinate system associated with the first coordinate system is based at least in part on a starting position of the substrate. Therefore, by converting the coordinates of the alignment features from the predefined layout to the first coordinate system using a mathematical transformation, the expected positions of all alignment features, including the first alignment feature and the second alignment feature, are known.

[0107] By determining the x-coordinate and y-coordinate of each first alignment feature, the image processing software determines at least the alignment of the first alignment features. As described herein, the y-direction is the scanning direction of the substrate, and the x-direction is the direction perpendicular to the y-direction in the plane of the substrate. If the first alignment features should have the same x-coordinate value, the degree to which the x-coordinates of the first alignment features are different indicates the rotation error of the substrate. As described elsewhere herein, the substrate positioning system is operable to incrementally rotate the substrate so that it aligns the x-coordinates of the first alignment features according to the alignment error determined from processing one or more images of the substrate. The rotation angle can be defined as the difference in the x-coordinates of the first alignment features divided by the difference in the y-coordinates of the first alignment features, in radians. The positioning system can also position the substrate to correct the global x-error of the substrate within the deviation range of the aligned x-coordinates of the first alignment features from the expected position of the substrate in the predefined substrate processing scheme. Alternatively, in order to capture the image of the alignment feature, the position of the camera can be adjusted for the global x-error of the substrate.

[0108] The positioning system can also be used to position a substrate or a portion of a substrate in the z direction, which is a direction substantially perpendicular to the substrate processing surface of the printing system (and perpendicular to the x and y directions). The positioning system may have a precision z-actuating component, such as a z-axis linear actuator connected to the substrate engaging portion of the positioning system, to perform z-direction positioning of the substrate portion engaged with the positioning system. In many cases, the substrate engages with the positioning system at the edge of the substrate, so the z-actuating component positions the edge of the substrate in the z direction. This can play a role in at least slightly positioning the entire substrate in the z direction and / or positioning the edge of the substrate in the z direction. In many cases, the substrate floats on an air cushion that accurately defines the gap between the substrate and the substrate processing surface, regardless of the movement of the positioning system. The air cushion and the positioning system work together to accurately position the substrate above the substrate processing surface at a distance predefined in the substrate processing scheme, and can flatten the substrate with high precision over the entire range of the substrate, including the edge portion where the positioning system engages the substrate.

[0109] The image processing and alignment operations described above may be performed while the substrate is positioned at the output side of the printing system after the first scan. If the substrate is not fully scanned to the output side of the printing system during the first scan, the substrate may remain in a partially scanned position while the image processing and alignment are performed, or the substrate may be moved back to the input end of the printing system for alignment. After the substrate is processed and positioned according to the substrate processing plan, a second scan is performed, wherein the positioning system moves the substrate from the output side of the printing system to the input side, or vice versa. During the second scan, a second camera system including one or more cameras captures multiple second images of the substrate. Each camera of the second camera system is positioned according to the expected position of the one or more second alignment features to correct the expected position in the predefined substrate layout according to the alignment operations performed after the first scan.

[0110] The second camera system has high magnification cameras to capture high resolution images of the second alignment features. In one case, the field of view of the high magnification cameras is approximately 1 mm, so each high magnification camera can capture alignment features that are less than 1 mm in size, and if the alignment features are spaced less than 1 mm apart, more than one alignment feature may be captured in a single scan. Typically, when scanning the substrate, the cameras of the second camera system are activated when the alignment feature to be imaged arrives within the field of view of one of the cameras of the second camera system, and are turned off when the alignment feature is expected to disappear from the field of view. The predefined layout of the substrate is used to determine the expected arrival time of the alignment features into the field of view of the cameras, and corrections are made for any positioning of the substrate performed during calibration.

[0111] The second scan can capture images of all the second alignment features. However, in some cases, it may not be possible to capture images of all the second alignment features in one scan. For example, if some of the second alignment features are too close to be imaged by one camera at the speed of the second scan, one or more of the second alignment features may be missed during the second scan due to the cycle time of the camera, and a third scan may be required to capture those missed second alignment features. In this case, an alternative approach is to slow down the scan speed so that all features are imaged in one scan. Another option is to use multiple cameras to image the alignment features in a column.

[0112] Each second image is processed by image processing software to determine the actual position of at least two second alignment features for each panel defined on the substrate. Because the layout of the substrate is usually known in advance, the camera of the second camera system is deployed to capture images of each panel defined on the substrate. Therefore, each camera of the second camera system captures images of at least two alignment features for each panel defined on the substrate. The camera of the second camera system is a high-power camera with a limited field of view, but because the substrates are aligned, the camera of the second camera system is positioned using the expected position of the second alignment features in the predefined layout, and each second image contains a high-resolution image of at least one second alignment feature. The accurately determined actual position of the second alignment features is used to adjust the printing scheme to account for any errors in positioning the panel on the substrate.

[0113] In the case where six panels are defined across the width of the substrate, the second camera system may include six high-power cameras positioned at locations where the second alignment features are expected to appear on the substrate. When scanning the substrate during the second scan, each camera of the second camera system captures one or more images of the substrate. If necessary, multiple images can be logically stitched together by image processing software, or images can be captured only near the expected locations of the alignment features so that there are gaps between the locations of the images. In any case, the six high-power cameras capture images of at least two second alignment features for each panel defined on the substrate. Capturing more than two images of the second alignment features for each panel can increase the certainty of panel positioning and system calibration.

[0114] It should be noted that a printing system configured with a single camera can be used to align and calibrate the printing system with substrates having different layouts and sizes. In general, if the printing system has n high-power cameras and the substrate has m panels, the substrate with m panels can be aligned and calibrated with the printing system if m is less than n. Since the travel range of the high-power cameras is known and the cameras can be positioned based on the known travel range, if the number of cameras is the same as the number of panels, the cameras can be positioned at the expected position x of the alignment feature. The same is true for substrates with portions having different panel layouts. For example, the substrate can have a first portion that defines three panels; and a second portion that defines six panels. A portion of the six high-power cameras of the second camera system, in this example three cameras, can be used to image the second alignment features of the three panels of the first portion, and all cameras can be used to image the second alignment features of the panels of the second portion. If the number of panels in the second portion is less than the total number of cameras of the second camera system, a second portion of the cameras of the second camera system can be used to image the second alignment features of the panels of the second portion.

[0115] The first camera system and the second camera system are respectively coupled to the printing support substantially as described elsewhere herein. Each camera has a carriage that is connected to a rail of the printing support. The printing support may be defined as having two rails, each camera system being supported by one rail. Alternatively, the two camera systems are supported by only one rail. In the case of two rails, the camera of the first camera system may be coupled to and driven along the first rail, while the camera of the second camera system may be coupled to and driven along the second rail. Thus, the range of motion of each camera of the first camera system is limited by the adjacent camera, but since the camera of the first camera system is a wide-angle camera, the first image can be captured by positioning the camera of the first camera system at a location where the first alignment feature is expected to appear. The same is true for the camera of the second camera system. If portions of the substrate have a different panel layout that requires repositioning the camera during the second scan, the camera of the second camera system may also be repositioned during the second scan. In some cases, the camera of the second camera system may be slightly moved during the scan to capture an image of the second alignment feature having a near x-coordinate.

[0116] Fig. 9 is an isometric schematic diagram of a printing assembly 900 according to one embodiment. The printing assembly 900 has a plurality of cameras deployed in a first camera system 902 and a second camera system 904. The printing assembly 900 can be used to practice the above-described embodiments using the first camera system and the second camera system. The first camera system 902 includes a plurality of first cameras 906, and the second camera system 904 includes a plurality of second cameras 908. The first camera 906 and the second camera 908 can be the same type of camera or different types of cameras. In one embodiment, the first camera 906 is a wide-angle camera, and the second camera 908 is a high-resolution camera.

[0117] The printing assembly 900 has a printing support 910 similar to Figure 1 The printing support 910 supports the first camera 906 and the second camera 908 to cross the substrate 912 supported by the substrate support 914 below the printing support 910. Not shown here, the dispenser assembly 114 can be connected to the printing support 910, such as Figure 1 Note: The dimensions of the printing support 910, substrate 912, and substrate support 914 are shown truncated.

[0118] The first camera 906 and the second camera 908 are coupled to and supported by the printing support 910 in a spaced relationship from the substrate support 914, thereby providing a gap between the printing support 910 and the device supported by the substrate 912. The cameras 906 and 908 are each coupled to a camera bracket 916. The camera brackets 916 coupled to the first camera 906 are each coupled to a first rail of the printing support 910, which is not visible here, but can be a groove located in the lower surface of the printing support 910 facing the substrate support 914. The camera bracket 916 coupled to the second camera 908 is coupled to the second rail of the printing support 910 in a similar manner. The camera brackets 916 are configured to move relative to each other on the two rails without colliding, thereby enabling the first camera 906 and the second camera 908 to be positioned along the printing support 910 without interference between any of the first cameras 906 and any of the second cameras 908. This enables the first camera 906 to be moved and positioned at any desired position relative to the substrate 912, while also positioning the second camera 908 at any desired position independent of the first camera 906. Typically each camera support 916 has an actuator, such as a driven wheel or air bearing, which engages a groove or shelf formed on the lower surface or in the upper surface of the support 910 to provide positioning capabilities. The cameras 906 and 908 are coupled to the camera support 916 in an orientation that allows the field of view of each camera 906 and 908 to encompass a portion of the substrate 912. It should be noted that some cameras 906 and 908 may be fixed to the printing support 910 and not movable relative to the printing support 910, but at least some cameras 906 and 908 may be movable relative to the printing support 910. For example, the outer cameras of each camera group may be fixed, while the cameras between the outer cameras may be actuated.

[0119] The features of several embodiments are summarized above so that those skilled in the art can better understand aspects of the present disclosure. Those skilled in the art will appreciate that other processes and structures can be easily designed or modified based on the present disclosure to achieve the same purpose and / or the same advantages as the embodiments described herein. Those skilled in the art will also appreciate that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that various changes, substitutions, and modifications may be made without violating the spirit and scope of the present disclosure.

Claims

1. A printing method, characterized in that: include: floating the substrate on an air-bearing substrate support of a printing system; Acquire a low-resolution image and a high-resolution image of a substrate loaded in a printing system, wherein Low-resolution images are acquired by a wide-angle camera, and High-resolution images are acquired by a high-magnification camera; determining an actual position of a first alignment feature on the substrate in a reference frame of the printing system based on the low resolution image; determining expected positions of a plurality of second alignment features on the substrate based on the actual positions of the first alignment features; determining actual positions of the plurality of second alignment features in a reference system of the printing system based on the expected positions of the second alignment features and the high resolution image; determining target positions of a plurality of printing areas on the substrate based on the actual position of the second alignment feature; as well as controlling the ejection of printing material onto the substrate in the plurality of printing areas based on the target positions of the printing areas, wherein controlling the ejection of printing material comprises moving the print head assembly along the printing support while ejecting the printing material from the dispensing nozzle of the print head assembly onto the printing area of ​​the substrate, and The print head assembly includes a dispensing nozzle extending to an air bearing substrate support, and the print head assembly is movable along a guide rail of the print support by operating a print carriage.

2. The printing method according to claim 1, characterized in that: the low-resolution image comprising the first alignment feature, the high resolution image includes the second alignment feature, and Based on the expected position of the second alignment feature, a high-power camera is positioned to acquire the high-resolution image.

3. The printing method according to claim 2, characterized in that: The wide angle camera captures a low resolution image during a first scan of the substrate from an input side of the printing system to an output side of the printing system; and The high-power camera captures the high-resolution image during a second scan of the substrate from the output side of the printing system to the input side of the printing system.

4. The printing method according to claim 3, characterized in that: Also includes: The substrate is aligned between the first scan and the second scan.

5. The printing method according to claim 4, characterized in that: Aligning the substrate includes aligning the substrate along two orthogonal directions.

6. The printing method according to claim 1, characterized in that: Also includes: A placement error of the substrate is determined, wherein determining target positions of the plurality of print areas includes compensating for the placement error.

7. The printing method according to claim 2, characterized in that: Also includes: before acquiring the low-resolution image with the wide-angle camera, moving the wide-angle camera along the print support to a position corresponding to the expected position of the first alignment feature on the substrate; and Prior to acquiring a high-resolution image, a high-magnification camera is moved along the print support to a position corresponding to the expected position of the second alignment feature on the substrate.

8. The printing method according to claim 1, characterized in that: The low-resolution image is acquired during a first scan of the substrate from an input side of the printing system to an output side of the printing system; and the high-resolution image is acquired during a second scan of the substrate from an output side of the printing system to an input side of the printing system.

9. The printing method according to claim 8, characterized in that: Also includes: The substrate is aligned between the first scan and the second scan.

10. The printing method according to claim 9, characterized in that: Aligning the substrate includes aligning the substrate along two orthogonal directions.

11. The printing method according to claim 10, characterized in that: Also includes: A placement error of the printed area is determined.

12. The printing method according to claim 11, characterized in that: The placement error is an alignment error or a rotation error.

13. The printing method according to claim 12, characterized in that: Also includes: The actual position of the edge of the printing area is determined.

14. The printing method according to claim 13, characterized in that: Also includes: A relationship between the expected position and the actual position of the second alignment feature is determined.

15. A printing method, characterized in that: include: floating the substrate on an air-bearing substrate support of a printing system; capturing a plurality of low-resolution images of a substrate loaded in a printing system with a camera configured to have a first resolution or a first field of view during a plurality of scans of the substrate; determining actual positions of a plurality of first alignment features on the substrate in a reference frame of the printing system based on the low resolution image; adjusting the camera to have a second resolution or a second field of view, wherein the second resolution is higher than the first resolution and the second field of view is narrower than the first field of view; During the plurality of scans, acquiring a plurality of high-resolution images of the substrate with the camera adjusted to have a second resolution or a second field of view; determining expected positions of a plurality of second alignment features on the substrate based on an actual position of at least one of the first alignment features; determining an actual position of the second alignment feature in a reference frame of the printing system based on the expected position of the second alignment feature and the high resolution image; determining target positions of a plurality of printing areas on the substrate based on the actual position of the second alignment feature; as well as Based on the target position of the printing area, controlling the printing material to be ejected onto the substrate in the printing area, wherein controlling the ejection of printing material comprises moving the print head assembly along the printing support while ejecting the printing material from the dispensing nozzle of the print head assembly onto the printing area of ​​the substrate, and The print head assembly includes a dispensing nozzle extending to an air bearing substrate support, and the print head assembly is movable along a guide rail of the print support by operating a print carriage.

16. The printing method according to claim 15, characterized in that: Also includes: Before starting the multiple scans, the camera is moved to a target position.

Images