FIELD OF TECHNOLOGY- The following relates to optical bonding of substrates and more specifically to embodiments of a machine, system, and method of automated optical bonding of substrates. 
BACKGROUND- Optical bonding of a transparent substrate, such as a sheet of glass, to another transparent substrate, or to a video screen such as an electronic display, may improve the ruggedness and enhance the optical clarity in ambient light. Bonding transparent substrates to each other presents many difficulties, including maintaining the structural integrity of the bonded substrates and manipulating the fill material used to bond the substrates. Specifically, air pockets may form in the fill material between the two substrates during the placement and bonding process. One cause of air pockets is attributed to the placement of a glass sheet onto another sheet of glass. Another cause is the inability to manipulate and work with the fill materials used in the optical bonding processes. The presence of air pockets between the bonded substrates results in cracks at locations where air pockets are present. 
- Accordingly, a need exists for an optical bonding machine, system, and method that address the difficulties in the art. 
SUMMARY- A first general aspect relates to a robotic placement machine configured to attach to a Y-axis actuator for moving left and right along an Y-axis and a X-axis actuator for moving back and forth along an X-axis, the robotic placement machine comprising a base operably connectable to at least one of the Y-axis actuator and the X-axis actuator, the base having a first end and a second end, a first Z axis actuator coupled to the first end of the base, the first Z axis actuator capable of moving up and down a first Z axis, a second Z axis actuator coupled to the second end of the base, the second Z axis actuator capable of moving up and down a second Z axis, and a pick and place plate operably connected to the first Z axis actuator and the second Z axis actuator, wherein the first Z axis actuator and the second Z axis actuator are each capable of moving independently of each other to tilt the pick and place plate. 
- A second general aspect relates to system comprising a first machine, wherein the first machine includes a valve coupled to a first end effector, the valve applying a material around a perimeter of a first substrate to form a dam, a second machine, wherein the second machine includes a custom head coupled to a second end effector, the custom head dispensing a fill material across a surface of the first substrate, wherein the dispensed fill material has a variable fill height, and a third machine, wherein the third machine includes a third end effector, the third end effector configured to pick a second substrate and controllably lower the second substrate onto the first substrate, wherein each of the first machine, second machine, and third machine are operably connected. 
- A third general aspect relates to an optical bonding method comprising dispensing dam material around a perimeter of the first substrate to form a dam, dispensing a fill material across a surface of the first substrate to achieve a largest fill height proximate a rear edge of the first substrate and a lowest fill height proximate a front edge of the first substrate, placing a second substrate into contact with the fill material proximate the rear edge of the first substrate at an angle relative to the first substrate, and controllably lowering the second substrate onto the first substrate until the second substrate is bonded to the first substrate to prevent and eliminate air bubbles between the first and second substrates. 
- A fourth general aspect relates to an optical bonding method comprising dispensing dam material around a perimeter of the first substrate to form a dam, dispensing a fill material across a surface of the first substrate to achieve a largest fill height proximate a middle portion of the first substrate, placing a second substrate into contact with the fill material proximate the middle portion of the first substrate, and controllably lowering the second substrate onto the first substrate substantially parallel to the first substrate until the second substrate is bonded to the first substrate to prevent and eliminate air bubbles between the first and second substrates. 
- The foregoing and other features of construction and operation will be more readily understood and fully appreciated from the following detailed disclosure, taken in conjunction with accompanying drawings. 
BRIEF DESCRIPTION OF THE DRAWINGS- Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein: 
- FIG. 1 depicts a front view of an embodiment of a system having an embodiment of a first system, second system, and a third system; 
- FIG. 2A depicts a top view of an embodiment of a first substrate; 
- FIG. 2B depicts a perspective view of an embodiment of the first substrate; 
- FIG. 3A depicts a top view of an embodiment of a second substrate; 
- FIG. 3B depicts a perspective view of the second substrate; 
- FIG. 4 depicts a front view of an embodiment of the first machine; 
- FIG. 5 depicts a perspective view of an embodiment of a first end effector; 
- FIG. 6A depicts a front view of an embodiment of the first end effector; 
- FIG. 6B depicts a top view of an embodiment of the first end effector; 
- FIG. 6C depicts a side view of an embodiment of the first end effector; 
- FIG. 7 depicts a top view of an embodiment of a first substrate having a dam; 
- FIG. 8 depicts a front view of an embodiment of a second machine; 
- FIG. 9 depicts a perspective view of an embodiment of a second end effector; 
- FIG. 10A depicts a top view of an embodiment of the second end effector; 
- FIG. 10B depicts a front view of an embodiment of the second end effector; 
- FIG. 10C depicts a side view of an embodiment of the second end effector; 
- FIG. 11 depicts a top view of an embodiment of the first substrate having some fill material dispensed within the dam; 
- FIG. 12 depicts a top view of an embodiment of the first substrate after fill material has been dispensed across its surface; 
- FIG. 13A depicts a cross-section view of a first embodiment of the first substrate after fill material has been dispensed across its surface; 
- FIG. 13A depicts a cross-section view of a second embodiment of the first substrate after fill material has been dispensed across its surface; 
- FIG. 14 depicts a front view of an embodiment of a third machine; 
- FIG. 15 depicts a perspective view of an embodiment of a third end effector; 
- FIG. 16A depicts a top view of an embodiment of the third end effector a distance above an underside assembly; 
- FIG. 16B depicts a perspective view of an embodiment of the third end effector a distance above an underside assembly; 
- FIG. 16C depicts a front view of an embodiment of the third end effector a distance above an underside assembly; 
- FIG. 16D depicts a side view of an embodiment of the third end effector a distance above an underside assembly; 
- FIG. 17A depicts a top view of an embodiment of the third end effector at initial contact with the first substrate; 
- FIG. 17B depicts a perspective view of an embodiment of the third end effector at initial contact with the first substrate; 
- FIG. 17C depicts a front view of an embodiment of the third end effector at initial contact with the first substrate; 
- FIG. 17D depicts a side view of an embodiment of the third end effector at initial contact with the first substrate; 
- FIG. 18A depicts a top view of an embodiment of the third end effector lowering at an angle onto the first substrate; 
- FIG. 18B depicts a perspective view of an embodiment of the third end effector lowering at an angle onto the first substrate; 
- FIG. 18C depicts a front view of an embodiment of the third end effector lowering at an angle onto the first substrate; 
- FIG. 18D depicts a side view of an embodiment of the third end effector lowering at an angle onto the first substrate; 
- FIG. 19A depicts a top view of an embodiment of the third end effector as the first substrate and the second substrate are bonded; 
- FIG. 19B depicts a perspective view of an embodiment of the third end effector as the first substrate and the second substrate are bonded; 
- FIG. 19C depicts a front view of an embodiment of the third end effector as the first substrate and the second substrate are bonded; 
- FIG. 19D depicts a side view of an embodiment of the third end effector as the first substrate and the second substrate are bonded; 
- FIG. 20A depicts a top view of a first embodiment of a second substrate lowering onto the first substrate causing a capillary effect on the fill material; 
- FIG. 20A depicts a top view of a second embodiment of a second substrate lowering onto the first substrate causing a capillary effect on the fill material; 
- FIG. 21 depicts a perspective view of an embodiment of a robotic placement machine; 
- FIG. 22 depicts a perspective view of an embodiment of the robotic placement machine, wherein the pick and place plate is in a horizontal position; and 
- FIG. 23 depicts a perspective view of an embodiment of the robotic placement machine, wherein the pick and place plate is in a tilted position. 
DETAILED DESCRIPTION- A detailed description of the hereinafter described embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. Although certain embodiments are shown and described in detail, it should be understood that various changes and modifications may be made without departing from the scope of the appended claims. The scope of the present disclosure will in no way be limited to the number of constituting components, the materials thereof, the shapes thereof, the relative arrangement thereof, etc., and are disclosed simply as an example of embodiments of the present disclosure. 
- As a preface to the detailed description, it should be noted that, as used in this specification and the appended claims, the singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise. 
- Referring to the drawings,FIG. 1 depicts an embodiment of system100. System100 may be an optical bonding system, liquid bonding system, liquid optical bonding system, glass lamination system, a system for bonding two transparent substrates together, and the like. System100 may include afirst machine30, asecond machine50, athird machine70, and a conveyor system90 connecting thefirst machine30, thesecond machine50, and thethird machine70. Eachmachine30,50,70 may perform one or more tasks to accomplish the bonding of two substrates. However, embodiments of system100 may include less than three machines and may include more than three machines depending on the number of tasks to be performed by each machine. System100 also includes afirst substrate10 and asecond substrate20, wherein thesecond substrate20 is bonded to thefirst substrate10. Thefirst substrate10 has a front edge11 (first end), amiddle portion13, and a rear edge12 (second end), as shown inFIGS. 2A and 2B. Thesecond substrate20 has a front edge21 (first end), amiddle portion23, and a rear edge22 (second end), as shown inFIGS. 3A and 3B. The first andsecond substrates10,20 may be transparent substrates. Embodiments of the first andsecond substrates10,20 may be sheets of glass of varying size (e.g. small and large), plastic, and the like. Further embodiments of thesecond substrate20 may be a protective, transparent sheet of glass to be placed onto thefirst substrate10, for example, thefirst substrate10 may be a glass display of an electronic device, such as a cell phone screen/cover or flat screen television screen. The first andsecond substrates10,20 may also be opaque or other than transparent, or one of the first andsecond substrates10,20 may be transparent while the other is opaque or other than transparent. The first andsecond substrates10,20 are bonded together with afill material5.Fill material5 may be an optically clear adhesive, such as DuPont® Vertak family of adhesives, or any clear adhesive that may quickly cure under UV and efficiently adhere to glass and similar surfaces. 
- Referring now toFIG. 4, embodiments of afirst machine30 of system100 may include aframe40, an X-axis actuator, a Y-axis actuator, a Z-axis actuator, and afirst end effector38. Thefirst machine30 may utilize a robotic platform to perform automated tasks with accuracy, precision, and repeatability. For example, thefirst machine30 may be a Gantry robot having three principal axes (Cartesian coordinates) controlling linear motion, wherein the horizontal member(s) may be supported at both ends. Thefirst machine30 may also be any robotic manipulator such as a selective compliant assembly robot arm (SCARA) system, linear robot, multi-axis robot arm system, and the like. However, an embodiment of thefirst machine30 will now be described as utilizing a Gantry robot for exemplary purposes. Thefirst end effector38 may refer to any device(s) attached to a X, Y, Z or other axis of movement to perform a variety of tasks, such as dispensing, picking and placing, routing, and the like. For instance, thefirst end effector38 is capable of rotation about the Z axis, and may move left and right along the Y axis by sliding along the Y axis actuator, and move back and forth along the X axis by sliding with the Y axis actuator as it slides along the X axis actuator. Additionally, thefirst end effector38 may move up and down on the Z-axis by sliding along the Z-axis actuator. The X-axis actuator, the Y-axis actuator, and the Z-axis actuator may be a ball screw slide, linear motion slide, a linear actuator, and the like. Moreover, theframe40 may provide a structure surrounding the components of thefirst machine30. Theframe40 may allow for panels to be attached providing an enclosure for thefirst machine30. The panels attached to theframe40 may be a combination of both solid panels and see-through panels, such as Plexiglas®, glass, plastic, and the like, to allow viewing of the operation of thefirst machine30. 
- FIGS. 4-6C depict an embodiment of afirst machine30 including at least one vacuum plate31 coupled to an underside32, afirst end effector38, aheight sensor34 coupled to the first end effector, at least onevalve33 coupled to thefirst end effector38, aUV wand45 coupled to thefirst end effector38, a light source proximate thefirst end effector38, avision system39, and a conveyor system90 for moving thefirst substrate10 to and from thefirst machine30. As thefirst substrate10 enters thefirst machine30 on conveyor system90, a vacuum plate coupled to an underside, or support substrate, may be raised up to thefirst substrate10. Alternatively, thefirst substrate10 may be lowered to the vacuum plate coupled to the underside. Other methods known to those skilled in the art may be used to place thefirst substrate10 into physical contact with the vacuum plate of thefirst machine30. When thefirst substrate10 is positioned above the vacuum plate, the vacuum plate may secure thefirst substrate10 in a flat position and prevent translational movement, sliding, shifting, etc., of thefirst substrate10. The underside of thefirst machine30 may include one or more vacuum plates, depending on the size of thefirst substrate10. Once thefirst substrate10 is held in place by the vacuum plate, aheight sensor34 coupled to thefirst end effector38 may engage thefirst substrate10 to probe the surface of thefirst substrate10, such as a target fill area and the perimeter of thefirst substrate10. Theheight sensor34 may probe the surface height of thefirst substrate10 to detect warpage or other deformities in the surface of thefirst substrate10. In one embodiment, theheight sensor34 may be a contact/touch probe relying on physical interaction between a probe arm and the surface of thefirst substrate10. In another embodiment, theheight sensor34 may be a laser probe which avoids physically contacting the surface of thefirst substrate10. 
- Theheight sensor34 may be connected to a mountingplate44a,wherein the mountingplate44ais connected to anindependent Z actuator49a,such as a ball screw slide, to allow for movement up and down along a Z axis. Theindependent Z actuator49amay be connected to the general structure of thefirst end effector38. Thus, theheight sensor34 may be able to move up and down independent of thefirst end effector38 through actuation of theindependent Z actuator49aassociated with theheight sensor34. A mounting plate, such as mountingplates44a,44b,may be any component(s), rigid or otherwise, that may be used to connect, secure, attach, etc., a component of thefirst machine30 to thefirst end effector38. Likewise, embodiments of afirst machine30 may include at least onevalve33 coupled to thefirst end effector38. The first valve33 (and/or valve assembly) may be connected directly or indirectly to a mountingplate44b,wherein the mountingplate44bis connected to anindependent Z actuator49b,such as a ball screw slide, to allow for movement up and down along a Z axis. Theindependent Z actuator49bmay be connected to the general structure of thefirst end effector38. Thus, thevalve33 may be able to move up and down independent of thefirst end effector38 through actuation of theindependent Z actuator49bassociated withvalve33. 
- Referring still toFIGS. 4-6C, at least onevalve33 may be coupled to thefirst end effector38 to create adam35 along a perimeter of thefirst substrate10. In other words, thedam35 may be applied along a perimeter of a predefined area wherefill material5 may be dispensed from acustom head53 of thesecond machine50, as shown inFIG. 7. Thedam35 may extend to the edges of thefirst substrate10 or may be a distance from the edges of thefirst substrate10. Thevalve33 may be a single dispensing valve. Moreover, movement of thefirst end effector38 along the perimeter of thefirst substrate10 whilevalve33 is coupled to thefirst end effector38 allowsvalve33 to dispense an amount of dam material necessary to create adam35 according to the required/desired properties and specifications.Dam35 material may include UV (ultraviolet) cure adhesive or material. Thedam35 may act as a spacer between thefirst substrate10 and thesecond substrate20 when the first andsecond substrates10,20 are bonded together. Thus, the height, girth, curvature, etc. of thedam35 may vary according to the space desired/required between the first and thesecond substrates10,20 when bonded. Embodiments ofdam35 include a height ranging from0.1mm and0.7 mm high, and a width ranging from0.2 mm to0.5 mm. Thedam35 may be applied as a bead along the perimeter of thefirst substrate10 or may be applied flat along the perimeter of thefirst substrate10, depending on the desired/required properties and specifications. Additionally, thedam35 may act as a retainer, barrier, wall, boundary, and the like, for thefill material5 dispensed on the surface of thefirst substrate10 in thesecond machine50. Thedam35 may also includevents36 to allow air to escape during the placement of thesecond substrate20 onto thefirst substrate10. In addition,excess fill material5 may also escape throughvents36 during some applications.Vents36 may be a gap, break in thedam35, aperture, slot, hole, opening, and the like. The number and placement ofvents36 may vary according to required/desired specifications. In one embodiment, vents36 may be placed at the two corners and at the middle of thedam35 adjacent to thefront edge11 of thefirst substrate10. In another embodiment, asingle vent36 may be placed at some point between the corners of thedam35 adjacent to thefront edge11. Other embodiments include a combination ofvents36 at the corners of thedam35 and at points between the corners of thedam35.Vents36 may also be located on thedam35 adjacent to the sides of thefirst substrate10 to assist the escape of air andexcess fill material5 if the flow offill material5 is irregular during placement of thesecond substrate20. 
- Embodiments of thefirst machine30 may also include a light source in communication with an ultraviolet (UV)wand45 coupled to thefirst end effector38. TheUV wand45 may be connected, directly or indirectly, to a mountingplate44c,wherein the mountingplate44cis connected to anindependent Z actuator49c,such as a ball screw slide, to allow for movement up and down along a Z axis. Theindependent Z actuator49cmay be connected to the general structure of thefirst end effector38. Thus, theUV wand45 may be able to move up and down independent of thefirst end effector38 through actuation of theindependent Z actuator49cassociated withUV wand45. A mounting plate, such as mountingplates44a,44b,44cmay be any component(s), rigid or otherwise, that may be used to connect, secure, attach, etc., a component of system100 to thefirst end effector38. The UV wand may emit ultraviolet light to semi-cure, stabilize, seal, and/or freeze thedam35 material after application to the surface of thefirst substrate10. Thedam35 material may slump or otherwise need to be stabilized after application; therefore, movement of thefirst end effector38 along the perimeter of the first substrate10 (i.e. along the dam35) while theUV wand45 is coupled to thefirst end effector38 allows the UV wand to emit UV light to stabilize thedam35 material. The emitted/transmitted light from theUV wand45 may come from a light source, wherein theUV wand45 is in communication with and/or connected to the light source with aguide cable47.Guide cable47 may connect theUV wand45 coupled to thefirst end effector38 to a light source that may be proximate thefirst end effector38. The light source may be a source of ultraviolet radiation. Embodiments offirst machine30 include a light source suspended from theframe40 or other structural component of thefirst machine30 proximate thefirst end effector38. Other embodiments include a light source external to thefirst machine30, wherein theguide cable47 connects theUV wand45 to the external light source. Even further embodiments include a light source coupled directly to thefirst end effector38. Those skilled in the art should appreciate that theguide cable47 may be a liquid filled cable, fiber optic cable, or similar cables associated with UV wands and UV light sources. 
- Further embodiments of thefirst machine30 of system100 may include avision system39 coupled to thefirst end effector38. Thevision system39 may be a camera or other suitable vision system capable of detecting the orientation, location, position, etc. of parts, such as thefirst substrate10, within thefirst machine30. 
- After one or more tasks associated with thefirst machine30 are completed, the vacuum plate may release thefirst substrate10, and then thefirst substrate10 may be forwarded to thesecond machine50 via conveyor system90, such as a conveyor belt. Those skilled in the art should appreciate that thefirst substrate10 may be manually loaded in and out of thefirst machine30. Furthermore, it should be understood that each task/component associated with thefirst machine30, including, inter alia,height sensor34 detecting surface height offirst substrate10,valve33 dispensing dam material to create adam35,UV wand45 to stabilize thedam35,vision system39 to monitor orientation of components, may be performed in separate machines. For instance, the tasks/components associated with thefirst machine30 may be performed in two or more machines, wherein thefirst substrate10 is transferred to each machine accordingly. 
- Referring now toFIG. 8, embodiments of asecond machine50 of system100 may include aframe60, an X-axis actuator, a Y-axis actuator, a Z-axis actuator, and asecond end effector58. Thesecond machine50 may utilize a robotic platform to perform automated tasks with accuracy, precision, and repeatability. For example, thesecond machine50 may be a Gantry robot having three principal axes (Cartesian coordinates) controlling linear motion, wherein the horizontal member(s) may be supported at both ends. Thesecond machine50 may also be any robotic manipulator such as a selective compliant assembly robot arm (SCARA) system, linear robot, multi-axis robot arm system, and the like. However, an embodiment of thesecond machine50 will now be described as utilizing a Gantry robot for exemplary purposes. Thesecond end effector58 may refer to any device(s) attached to a X, Y, Z or other axis of movement to perform a variety of tasks, such as dispensing, picking and placing, routing, and the like. For instance, thesecond end effector58 is capable of rotation about the Z axis, and may move left and right along the Y axis by sliding along the Y axis actuator, and move back and forth along the X axis by sliding with the Y axis actuator as it slides along the X axis actuator. Additionally, thesecond end effector58 may move up and down on the Z-axis by sliding along the Z-axis actuator. The X-axis actuator, the Y-axis actuator, and the Z-axis actuator may be a ball screw slide, linear motion slide, a linear actuator, and the like. Moreover, theframe60 may provide a structure surrounding the components of thesecond machine50. Theframe60 may allow for panels to be attached providing an enclosure for thesecond machine50. The panels attached to theframe60 may be a combination of both solid panels and see-through panels, such as Plexiglas®, glass, plastic, and the like, to allow viewing of the operation of thesecond machine50. 
- Embodiments of thesecond machine50 may include at least one vacuum plate coupled to an underside, or support frame, asecond end effector58, atreatment head54 coupled to thesecond end effector58, acustom head53 coupled to thesecond end effector54, avision system59, and a conveyor system90 for moving thefirst substrate10 to and from thesecond machine50. As thefirst substrate10 enters thesecond machine50 on conveyor system90, a vacuum plate coupled to an underside may be raised up to thefirst substrate10. Alternatively, thefirst substrate10 may be lowered to the vacuum plate coupled to the underside. Other methods known to those skilled in the art may be used to place thefirst substrate10 into physical contact with the vacuum plate. When thefirst substrate10 is positioned above the vacuum plate, the vacuum plate may secure thefirst substrate10 in a flat position and prevent translational movement, sliding, shifting, etc., of thefirst substrate10. The underside of thesecond machine50 may include one or more vacuum plates, depending on the size of thefirst substrate10. 
- With continued reference toFIG. 8, and additional reference toFIGS. 9-10C, thefirst substrate10 is held in place by the vacuum plate, atreatment head54 coupled to thesecond end effector58 may treat the surface of thefirst substrate10. In most embodiments, thetreatment head54 treats only the target fill area, wherein the target fill area may be defined as the surface area inside/within thedam35, or the majority of the surface area of thefirst substrate10. Treating the surface of thefirst substrate10 may require plasma treatment of the surface of thefirst substrate10 to change the surface energy of thefirst substrate10 to improve wetting and adhesion properties of the surface of thefirst substrate10. Thetreatment head54 may be referred to as a plasma head or surface treatment head. Moreover, movement of thesecond end effector58 back and forth across the target area may treat the surface of the first substrate with thetreatment head54 coupled to thesecond end effector58. Thetreatment head54 may be up to4 inches wide. Moreover, thetreatment head54 may be connected to a mountingplate64a,wherein the mountingplate64ais connected to anindependent Z actuator65a,such as a ball screw slide, to allow for movement up and down along a Z axis. Theindependent Z actuator65amay be connected to the general structure of thesecond end effector58. Thus, thetreatment head54 may be able to move up and down independent of thesecond end effector58 through actuation of theindependent Z actuator65aassociated with thetreatment head54. A mounting plate, such as mountingplates64a,64b,may be any component(s), rigid or otherwise, that may be used to connect, secure, attach, etc., a component ofsecond machine50 to thesecond end effector58. Likewise, embodiments of asecond machine50 may include acustom head53 coupled to thesecond end effector58. The custom head53 (and/or valve(s) assembly) may be connected directly or indirectly to a mountingplate64b,wherein the mountingplate64bis connected to anindependent Z actuator65b,such as a ball screw slide, to allow for movement up and down along a Z axis. Theindependent Z actuator65bmay be connected to the general structure of thesecond end effector58. Thus, thecustom head53 may be able to move up and down independent of thesecond end effector58 through actuation of theindependent Z actuator65bassociated with thecustom head53. A fluid reservoir may be operably attached to thecustom head53 through various means, such as a hose or other tube. The fluid reservoir may contain fillmaterial5, such as optically clear adhesive. 
- Furthermore, thecustom head53 may include a single dispensing valve or a plurality of dispensing valves for dispensing afill material5 onto thefirst substrate10. Thecustom head53 having a plurality of valves may speed up the fill process over a larger substrate due to a wider fill pattern, while a single dispensing valve may be helpful over smaller substrates due to a narrower fill pattern. Embodiments of thecustom head53 may include four, one inch-wide dispensing valves positioned in a side-by-side configuration, wherein each valve of the plurality of valves is level or substantially level with respect to the other valves forming thecustom head53. Those skilled in the art should appreciate that the configuration and placement of the valves of thecustom head53 may include other configurations and placement locations, but may typically remain proximate each other coupled to thesecond end effector58. Further embodiments ofcustom head53 may include anoutlet block66 positioned at the nozzle end of the dispensing valves to help generate the dispense pattern through each pass across thefirst substrate10. Moreover, thesecond machine50 may selectively operate thecustom head53 such that only one or more of the plurality of valves forming thecustom head53 dispensefill material5, while the other valves remain unused. The selective operation of the custom head53 (e.g. 2 of 4 valves dispensing fill material5) may be performed prior to operation of thesecond machine50 and/or during the operation of thesecond machine50. For instance, an embodiment of acustom head53 having four or more dispensing valves may operate only three of the four or more valves of thecustom head53, without the need for disassembly, and without the need to stop the functioning/operation of thesecond machine50. Because thesecond machine50 can selectively operate individual components of thecustom head53, the fill pattern may be narrowed or widened depending on the requirement/specification of the first substrate10 (e.g. size, fill area, time, etc). 
- Furthermore, movement of thesecond end effector58 following a fill pattern across thefirst substrate10 may dispense thefill material5 across the fill area of thefirst substrate10. The fill pattern of thefill material5 may start proximate thefront edge11 of thefirst substrate10, as shown inFIG. 11. Thefill material5 dispensed by thecustom head53 may start a distance from thedam35 proximate or otherwise near thefront edge11, and a distance from the sides of thefirst substrate10. The direction of the fill pattern may be from thefront edge11 to therear edge12 of thefirst substrate10, and generally, the surface of thefill material5 on thefirst substrate10 should not contain waves, divots, or other surface irregularities (i.e. the surface of thefill material5 may be smooth and continuous). Additionally, the movement of thesecond end effector58 may be to dispense a rectangular and/or linear pattern from one side to the other side, wherein one trip by thesecond end effector58 from side to side may be referred to as a pass. After a pass by thesecond end effector58, thesecond end effector58 may move a distance towards therear edge12, and make a pass back across (e.g. laterally) thefirst substrate10. The patterned movement of thesecond end effector58 may continue until reaching thedam35 proximate therear edge12. Those having skill in the requisite art should appreciate that thesecond end effector58 may follow various patterns and movements to apply thefill material5. Accordingly, thefill material5 may cover a large majority of the surface of thefirst substrate10. For example, thefill material5 may cover 85% to 95% of thefirst substrate10, as shown inFIG. 12. Each pass of thesecond end effector58 may dispense fillmaterial5 across (e.g. side-to-side) thefirst substrate10, between thedam35 or general target area in embodiments where nodam35 is formed, at a width corresponding to the number of operating valves and type of dispensing valve of thecustom head53. Thus, thecustom head53 may determine the width offill material5 being dispensed each pass of thesecond end effector58. 
- Moreover, with reference toFIGS. 11-13A, thefill material5 may be dispensed at a certain fill height, h. Fill height, h, may refer to the height of thefill material5 from the surface offirst substrate10, once dispensed from thecustom head53. The fill height, h, may be controlled by the speed of thesecond end effector58 during each pass across thefirst substrate10. For example, the slower thesecond end effector58 moves as it passes across thefirst substrate10, themore fill material5 may be dispensed at that location. The fill height, h, may also be controlled by the flow rates associated with the custom head53 (e.g. size of the outlets, types of valves, etc.) and ultimately by the amount offill material5 dispensed from thecustom head53. In most embodiments, thefill material5 is dispensed at a varying or variable fill height, h. In one embodiment, the variable fill height, h, may increase from thefront edge11 of thefirst substrate10 to arear edge12 of thefirst substrate10. In other words, the dispensedfill material5 may have a largest fill height, h, proximate or otherwise near therear edge12 of thefirst substrate10 and a lowest fill height, h, at thefront edge11 of thefirst substrate10. Embodiments of the varying fill height, h, may require thesecond end effector58 to make a first set of passes across thefirst substrate10 at a consistent first fill speed, then a second set of passes across thefirst substrate10 at a consistent second fill speed, and a third set of passes across thefirst substrate10 at a consistent third fill speed, wherein the first set of passes begins proximate thefront edge11, the third set of passes occurs proximate therear edge12, further wherein the first fill speed is faster than the second fill speed, and the third fill speed is the slowest fill speed. Further embodiments of the varying fill height, h, may include a plurality of fill zones67a,68a,69a.A fill zone67a,68a,69amay refer to a portion of the target fill area having a certain fill height, h, offill material5 depending on the fill rate of thecustom head53. Each fill zone67a,68a,69amay have the same fill height, h. Alternatively, each fill zone67a,68a,69amay have a fill height, h, which slightly increases in a direction toward therear edge12, as shown inFIG. 13A. Although only three fill zones67a,68a,69aare shown, those skilled in the art should appreciate that there may be more or less than three fill zones67a,68a,69a.Fill zone67a,the fill zone closest to thefront edge11, should have the lowest fill height, h. Fill zone68ashould have a fill height, h, greater than the fill zone67a,but less than fill zone69a.Accordingly, fill zone69a,or fill zone closes to therear edge12 should have the greatest fill height, h. 
- In another embodiment, with reference toFIG. 13B, the variable fill height, h, may be a constant height from thefront edge11 of thefirst substrate10 to amiddle portion13 of thefirst substrate10, and constant from therear edge12 to themiddle portion13, wherein the fill height, h, at themiddle portion13 is larger. In other words, the dispensedfill material5 may have a largest fill height, h, proximate or otherwise nearmiddle portion13 of thefirst substrate10 and a lowest fill height, h, proximate or otherwise near thefront edge11 andrear edge12 of thefirst substrate10. Embodiments of the varying fill height, h, may require thesecond end effector58 to make a first set of passes across thefirst substrate10 at a consistent first fill speed, then a second set of passes across thefirst substrate10 at a consistent second fill speed, and a third set of passes across thefirst substrate10 at a consistent third fill speed, wherein the first set of passes begins/occurs proximate or otherwise near thefront edge11, the second set of passes occurs proximate or otherwise near themiddle portion13, the third set of passes occurs proximate or otherwise near therear edge12, further wherein the first fill speed and the third fill speed is faster than the second fill speed. Further embodiments of the varying fill height, h, may include a plurality offill zones67b,68b,69b,as shown inFIG. 13B. Afill zone67b,68b,69bmay refer to a portion of the target fill area having a certain fill height, h, offill material5 depending on the fill rate of thecustom head53. Although only threefill zones67b,68b,69bare shown, those skilled in the art should appreciate that there may be more or less than three fillzones67b,68b,69b.Fillzone67b,can be the fill zone closest to thefront edge11. Fill zone68bcan be the fill zone proximate amiddle portion13. Fill zone69bcan be the fill zone closest to therear edge12. The fill zone68bshould have a fill height, h, greater than the fill height, h, offill zone67band fill zone69b.Accordingly, a fill zone proximate or otherwise near themiddle portion13 of thefirst substrate10, such as fill zone68b,should have the greatest fill height, h. 
- Further embodiments of thesecond machine50 of system100 may include avision system59 coupled to thesecond end effector58, and a heating system to heat thefill material5. Thevision system59 may be a camera or other suitable vision system capable of detecting the orientation, location, position, etc. of parts, such as thefirst substrate10, within thesecond machine50. Moreover, the heating system may include a heated valve(s) coupled to thesecond end effector58, a heated fluid hose through which thefill material5 travels from the fluid reservoir, or a heated fluid reservoir. Heating thefill material5 may help improve the wetting of thefill material5 by lowering the viscosity. The temperature range for heating the fill material may be between 30° C. to 50° C. 
- After one or more tasks associated with thesecond machine50 are completed, the vacuum plate may release thefirst substrate10, and then thefirst substrate10 may be forwarded to thethird machine70 via conveyor system90, such as a conveyor belt. Those skilled in the art should appreciate that thefirst substrate10 may be manually loaded in and out of thesecond machine50. Furthermore, it should be understood that each task/component associated with thesecond machine50, including, inter alia,treatment head54 treating the surface offirst substrate10,custom head53 dispensing fill material onto thefirst substrate10,vision system39 to monitor orientation of components, may be performed in separate machines. For instance, the tasks/components associated with thesecond machine50 may be performed in two or more machines, wherein thefirst substrate10 is transferred to each machine accordingly. 
- Referring now toFIGS. 14 and 15, embodiments of athird machine70 of system100 may include aframe80, anX axis actuator81, aY axis actuator82, and athird end effector78 having at least twoindependent Z actuators84a,84b.Thethird machine70 may utilize a robotic platform to perform automated tasks with accuracy, precision, and repeatability. For example, thethird machine70 may be a Gantry robot having three principal axes (Cartesian coordinates) controlling linear motion, wherein the horizontal member(s) may be supported at both ends. Thethird machine70 may also be any robotic manipulator such as a selective compliant assembly robot arm (SCARA) system, linear robot, multi-axis robot arm system, and the like. However, an embodiment of thethird machine70 will now be described as utilizing a Gantry robot for exemplary purposes. Thethird end effector78 may refer to any device(s) attached to a X, Y, Z or other axis of movement to perform a variety of tasks, such as dispensing, picking and placing, routing, and the like. Embodiments of thethird end effector78 may be a robotic placement system/machine, as described infra. For instance, thethird end effector78 may move left and right along the Y axis by sliding along theY axis actuator82, and move back and forth along the X axis by sliding with theY axis actuator82 as it slides along theX axis actuator81. Additionally, thethird end effector78 may move up and down on the Z axis by simultaneously actuating the firstindependent Z actuator84aand the secondindependent Z actuator84b.TheX axis actuator81, theY axis actuator82, and the first and secondindependent Z actuators84a,84bmay be a ball screw slide, linear motion slide, a linear actuator, and the like. Moreover, theframe80 may provide a structure surrounding the components of thethird machine70. Theframe80 may allow for panels to be attached providing an enclosure for thethird machine70. The panels attached to theframe80 may be a combination of both solid panels and see-through panels, such as Plexiglas®, glass, plastic, and the like, to allow viewing of the operation of thethird machine70. 
- Embodiments of thethird machine70 may include at least one vacuum plate coupled to anunderside assembly72, or support assembly, athird end effector78 including aheight sensor74 coupled to thethird end effector78, a pick andplace plate73 coupled to thethird end effector78, avision system59, and a conveyor system90 for moving thefirst substrate10 to thethird machine70, and for moving the bonded substrates to a cure oven, such as UV cure oven. As thefirst substrate10 enters thethird machine70 on conveyor system90, a vacuum plate coupled to anunderside assembly72 may be raised up to thefirst substrate10. Alternatively, thefirst substrate10 may be lowered to the vacuum plate coupled to theunderside assembly72. Other methods known to those skilled in the art may be used to place thefirst substrate10 into physical contact with the vacuum plate. When thefirst substrate10 is positioned above the vacuum plate, the vacuum plate may secure thefirst substrate10 in a flat position and prevent translational movement, sliding, shifting, etc., of thefirst substrate10. Theunderside assembly72 of thethird machine70 may include one or more vacuum plates, depending on the size of thefirst substrate10. 
- Asecond substrate20 may enter system100, in particular, thethird machine70 for optical bonding with thefirst substrate10. Thesecond substrate20 may be manually loaded in a slide table proximate or otherwise near thethird machine70 to introduce thesecond substrate20 into system100. Alternatively, the loading of thesecond substrate20 may be automated, such as a second conveyor system (e.g. conveyor belt). The location of the slide table for loading thesecond substrate20 may correspond to the location of the pick andplace plate73 of thethird end effector78. For instance, the slide table may be positioned such that thesecond substrate20 is loaded into thethird machine70 directly underneath or substantially underneath the pick andplace plate73 of thethird end effector78. In one embodiment, the slide table is positioned perpendicular to thethird machine70, wherein entry into thethird machine70 via slide table is proximate thethird end effector78. Once thesecond substrate20 is loaded proximate the pick andplace plate73, thethird end effector78 may lower down to engage thesecond substrate20 with the pick andplace plate73, wherein the pick andplace plate73 utilizes a vacuum force to secure (i.e. pick) thesecond substrate20. Alternatively, thesecond substrate20 may be raised to the pick andplace plate73; however, an automated or mechanical lift may be needed in addition to the manual loading, especially if the second substrate is a large sheet of glass. Accordingly, thethird end effector78 may be configured to pick thesecond substrate20 via the pick andplace plate73, wherein the pick andplace plate73 is coupled to thethird end effector78. 
- Moreover, aheight sensor74 coupled to thethird end effector78 may be used to locate and monitor alignment thesecond substrate20 as it enters thethird machine70. For example, theheight sensor74 may engage thesecond substrate20 to locate and align thesecond substrate20 with the pick andplace plate73. Theheight sensor74 may probe the surface of thesecond substrate20, and more specifically, the edges of thesecond substrate20 to ensure proper engagement with the pick andplace plate73. Furthermore, theheight sensor74 may be used to probe the surface (to determine the height) of thefirst substrate10 to locate the leading edge (i.e. rear edge12) of thefirst substrate10 and may determine the spatial location of the contact point between thesecond substrate20 and the first substrate10 (i.e. initial contact between therear edge12 of thefirst substrate10 and thefront edge21 of the second substrate20). Alternatively, theheight sensor74 may be used to probe the surface (to determine the height) of thefirst substrate10 to locate at least one therear edge12 and themiddle portion13 of thefirst substrate10 and may determine the spatial location of the contact point between thesecond substrate20 and the first substrate10 (i.e. initial contact between themiddle portion13 of thefirst substrate10 and themiddle portion23 of the second substrate20). In one embodiment, theheight sensor74 may be a contact/touch probe relying on physical interaction between a probe arm and the surface of thefirst substrate10. In another embodiment, theheight sensor74 may be a laser probe which avoids physically contacting the surface of thefirst substrate10. 
- Referring now toFIGS. 16A-19D, thethird end effector78 may be configured to pick and place asecond substrate20 onto thefirst substrate10 and controllably lower thesecond substrate20 onto the first substrate. As shown inFIG. 17D, thethird end effector78 may be configured to place asecond substrate20 onto thefirst substrate10 at a placement angle,0, and controllably lower thesecond substrate20 onto thefirst substrate10, wherein an initial contact between the first andsecond substrate10,20 occurs proximate therear edge12 of thefirst substrate10. As shown inFIG. 16D, thethird end effector78 may be configured to place thesecond substrate10 onto thefirst substrate10, wherein thesecond substrate20 is parallel or substantially parallel to the first substrate10 (i.e. controllably descend from position shown inFIG. 16D). 
- With reference toFIGS. 16A-16D, an embodiment of athird end effector78 positioned a distance above anunderside assembly72 is shown. In this position, thethird end effector78 has picked thesecond substrate10 and has moved into position proximate thefirst substrate10, which may be secured to a vacuum plate.FIGS. 17A-17D show an embodiment of athird end effector78 tilting to engage thefirst substrate10 at an angle. Through simultaneous actuation of at least two independentZ axis actuators84a,84b,thethird end effector78 may move up and down along a Z axis to descend towards the first substrate10 (or ascend away from the first substrate10). Through independent actuation of at least two Z-axis actuators84a,84b,thethird end effector78 may be able to tilt to achieve the desired angle of placement in embodiments where the contact between thefirst substrate10 and thesecond substrate20 is not parallel. Because the pick andplace plate73 is coupled to thethird end effector78, the pick andplace plate73 may also tilt according to the movement of thethird end effector78 Likewise, because thesecond substrate20 is secured to the pick andplace plate73, thesecond substrate20 may also tilt according to the movements of thethird end effector78. Therefore, the initial contact between thefirst substrate10 and thesecond substrate20 may be proximate therear edge12 of thefirst substrate10, at an angle of placement, Ø, between 0° and 20°. However, the angle of placement may be larger than 20° if required, and the capabilities of the two independent Z-axis actuators84a,84bmay be adjusted accordingly. 
- Once thesecond substrate20 has initially engaged thefirst substrate10, thethird end effector78 may controllably lower thesecond substrate20 onto thefirst substrate10, as shown inFIGS. 18A-18D. For instance, from the initial point of contact, thesecond substrate20 may be lowered at a calculated speed/velocity and angle. Controllably lowering thesecond substrate20 onto thefirst substrate10 may be gradual or proportional as thesecond substrate20 is placed onto thefirst substrate10. In other embodiments, controllably lowering thesecond substrate20 onto thefirst substrate10 may mean that the speed of placement may vary according to requirements/specifications of thesubstrates10,20 and/or fillmaterial5 being used. For example, as the angle between thesecond substrate20 and thefirst substrate10 decreases and nears zero degrees, thesecond substrate20 may be controllably slowed to allow proper contact between thesecond substrate20 and thefirst substrate10, and to control flow offill material5. Generally, the speed of placement is slow to avoid disrupting thefill material5 and inviting air bubbles to form between thesubstrates10,20 during the bonding process. Alternatively, controllably lowering thesecond substrate20 onto thefirst substrate10 may include a controlled descent of thethird end effector78 while thesecond substrate20 is operably attached to thethird end effector78 at an angle parallel to thefirst substrate10. 
- Moreover, controllably lowering thesecond substrate20 onto thefirst substrate10 may force thefill material5 to create a capillary or wave effect as it flows across the surface of thefirst substrate10 and/orsecond substrate20, as shown inFIG. 20A. In a first embodiment, air bubbles, formations, pockets, etc., may be prevented or eliminated because at the initial point of contact between therear edge12 of thefirst substrate10 and thefront edge21 of thesecond substrate20, thesecond substrate20 may immediately contact thefill material5. Contact with thefill material5 may be ensured because the largest fill height, h, is proximate therear edge12 of thefirst substrate10. Thus, the fill height, h, proximate therear edge12 of thefirst substrate10 may equal the height necessary to make immediate contact with thesecond substrate20 as thethird end effector78 places thesecond substrate20 into an initial contact position, as shown inFIG. 17D. As thesecond substrate20 is controllably lowered onto thefirst substrate10, thefill material5 may immediately begin flowing outward and towards thefront edge11 of thefirst substrate10. The varying (or declining fill height, h, fromrear edge12 to front edge11) fill height, h, across the surface of thefirst substrate10 may allow the smooth, wavelike flow of thefill material5, and may avoid overflow over the dam or fillmaterial5 passing through thevents36 in unnecessary excess. 
- In a second embodiment, air bubbles, formations, pockets, etc., may be prevented or eliminated because at the initial point of contact between thefirst substrate10 and thesecond substrate20, thesecond substrate20 may immediately contact thefill material5 at amiddle portion13,23 of thesubstrates10,20. Contact with thefill material5 may be ensured because the largest fill height, h, is proximate or otherwise near themiddle portion13 of thefirst substrate10. Thus, the fill height, h, proximate themiddle portion13 of thefirst substrate10 may equal the height necessary to make immediate contact with thesecond substrate20 as thethird end effector78 places thesecond substrate20 into an initial contact position, as shown inFIG. 16D. As thesecond substrate20 is controllably lowered onto thefirst substrate10, thefill material5 may immediately begin flowing outwards towards thefront edge11 andrear edge12 of thefirst substrate10. The varying (or declining fill height, h, from themiddle portion13 to thefront edge11 in one direction and to therear edge12 in an opposite direction) fill height, h, across the surface of thefirst substrate10 may allow the smooth, wavelike flow of thefill material5, and may avoid overflow over the dam or fillmaterial5 passing through thevents36 in unnecessary excess. 
- Accordingly, the capillary effect, or wavelike flow, of thefill material5 may prevent and eliminate the formation of air pockets during the bonding process, regardless of the size of thesubstrates10,20, as shown inFIG. 20B. Thethird end effector78 may controllably lower thesecond substrate20 onto thefirst substrate10 until the first andsecond substrates10,20 are bonded, as shown inFIGS. 19A-19D. In other words, thethird end effector78 may lower thesecond substrate20 onto thefirst substrate10 until the angle between thefirst substrate10 and thesecond substrate20 is 0° (i.e. flat), or until no space exists between the first andsecond substrates10,20. 
- Further embodiments of thethird machine70 of system100 may include avision system79 coupled to thethird end effector78 and a heating system. Thevision system79 may be a camera or other suitable vision system capable of detecting the orientation, location, position, etc. of parts, such as thefirst substrate10 and thesecond substrate20, within thethird machine70. Moreover, the heating system may include a heated valve(s) or other device for applying heat to the first andsecond substrates10,20. 
- Referring now toFIGS. 21-23, an embodiment of arobotic placement machine200 is shown. Therobotic placement machine200 may be used to place afirst substrate10, including a transparent substrate, onto asecond substrate20. Generally,robotic placement machine200 is used for optical bonding and similar glass lamination methods and systems. Therobotic placement machine200 may be configured to attach to a robotic platform capable of performing automated tasks with accuracy, precision, and repeatability. For example,robotic placement machine200 may be attached to a Gantry robot, or other robotic manipulator such as a selective compliant assembly robot arm (SCARA) system, linear robot, multi-axis robot arm system, and the like. Furthermore, therobotic placement machine200 may move left and right along the Y axis by sliding along theY axis actuator282, and move back and forth along the X axis by sliding with theY axis actuator282 as it slides along theX axis actuator281. TheX axis actuator281 may be interchangeable with theY axis actuator282. TheX axis actuator81 and theY axis actuator82 may be a ball screw slide, linear motion slide, a linear actuator, and the like. 
- Embodiments of therobotic placement machine200 may further include a base290 operably connected to theY axis actuator282, at least twoindependent Z actuators284a,284b,at least two mountingplates295a,295b,at least two bearingsystems220,240, a pick andplace plate250, anunderside251, at least oneUV wand275, aheight sensor274, and avision system279. Further embodiments of therobotic placement machine200 may be configured to attach, or may have, a Y-axis actuator282 for moving left and right along an Y axis and aX-axis actuator281 for moving back and forth along an X axis, and a base290 operably connectable to at least one of the Y-axis actuator281 and theX-axis actuator281, thebase290 having afirst end291 and asecond end291, a firstZ axis actuator284acoupled to the first end291of thebase290, the first Z-axis actuator284acapable of moving up and down a first Z axis, a secondZ axis actuator284bcoupled to thesecond end292 of thebase290, the secondZ axis actuator284bcapable of moving up and down a second Z axis, and a pick andplace plate250 operably connected to the firstZ axis actuator284aand the secondZ axis actuator284b,wherein the firstZ axis actuator284aand the secondZ axis actuator284bare each capable of moving independently of each other to tilt the pick andplace plate250. 
- Referring still toFIGS. 21-23, embodiments of arobotic placement machine200 may include a base290 operably connected to theY axis actuator282. The base290 may be directly or indirectly connected to theY axis actuator282. The base290 may be rigidly fixed to theY axis actuator282 or dynamically coupled to theY axis actuator282. Alternatively, thebase290 may be suspended from theY axis actuator282. The base290 may be a single structural component or a combination of structural components formed by rigid materials or by a combination of rigid and flexible materials that may provide structural integrity to therobotic placement machine200. The base290 may have afirst end291 and asecond end292. The firstZ axis actuator284amay be coupled to thefirst end291 of thebase290. Similarly, the secondZ axis actuator284bmay be coupled to thesecond end292 of thebase290. Embodiments of the first and secondZ axis actuators284a,284bmay be a ball screw slide, linear motion slide, a linear actuator, and the like. The first Z-axis actuator284amay operate independently of the second Z-axis actuator284b,but may function in unison as required. Accordingly, eachZ axis actuator284a,284bmay be actuated at different times, different speeds, etc. Thus, the firstZ axis actuator284aand the secondZ axis actuator284bare each capable of moving independently of each other to tilt the pick andplace plate250, and return the pick andplace plate250 back to a horizontal or substantially horizontal position. 
- Through simultaneous actuation of the first and secondZ axis actuators284a,284b,therobotic placement machine200 may move up and down, while keeping the pick andplace plate250 horizontal or substantially horizontal. Additionally, simultaneous actuation of the first and secondZ axis actuators284a,284bmay move therobotic placement machine200 up and down, while the pick andplace plate250 is tilted at an angle, maintaining the tilt angle during movement. Through independent actuation of the first and secondZ axis actuators284a,284b,therobotic placement machine200 may move or tilt the pick andplace plate250 from 0° to 20° with respect to a horizontal position. In some embodiments, independent actuation of the first and secondZ axis actuators284a,284bmay achieve tilt of the pick andplace plate250 and movement up and down along a Z axis. 
- Embodiments ofrobotic placement machine200 may also include afirst mounting plate295acoupled to the first Z-axis actuator284a,wherein the first Z-axis actuator284ais coupled to asecond surface297aof the mountingplate295a.Similarly, embodiments ofrobotic placement machine200 may include asecond mounting plate295bcoupled to the second Z-axis actuator284b,wherein the second Z-axis actuator284bis coupled to asecond surface297bof thesecond mounting plate295b.A mounting plate, such as mountingplates295a,295bmay be any component(s), rigid or otherwise, that may be used to connect, secure, attach, etc., the first and secondZ axis actuator284a,284bto a first andsecond bearing system220,240, respectively. For instance, afirst bearing system220 may be coupled to afirst surface296aof the first mountingplate295a.Similarly, asecond bearing system240 may be coupled to afirst surface296bof thesecond mounting plate295b.The operable communication between the first and second Z-axis actuators284a,284bmay allow therobotic placement machine200 to tilt as a single unit. In other words, the first andsecond bearing systems220,240 may mechanically allow and/or facilitate the tilt of the pick andplace plate250. Furthermore, first andsecond bearing systems220,240 may improve the efficiency and reduce the friction resulting from the actuation of the first and secondZ axis actuators284a,284b.Embodiments of the first andsecond bearing systems220,240 may include a bearing fitted within a housing fastened to the underside, capable of supporting a shaft to facilitate the tilt of the pick andplace plate250. Those skilled in the requisite art should appreciate that other bearing systems may be employed to facilitate the tilting of therobotic placement machine200, and should not be limited to the embodiments disclosed herein. 
- Moreover, the first andsecond bearing systems220,240 may also be coupled to anunderside251 or support substrate of therobotic placement machine200. Theunderside251 may be coupled, or in mechanical communication with a pick andplace plate250. In some embodiments, therobotic placement machine200 may include more than one pick andplace plate250 coupled to theunderside251. The pick andplace plate250 may be configured to pick, secure, grab, attach to, etc. a transparent substrate, such assecond substrate10. The pick andplace plate250 may be a vacuum plate configured to lock onto a substrate for controllable placement onto another substrate, such asfirst substrate10. 
- Further embodiments ofrobotic placement machine200 may include at least oneUV wand275 positioned on theunderside251. The UV wands245 may have the same structure and function ofUV wand45, described supra. Embodiments ofrobotic placement machine200 may include a plurality ofUV wands245 positioned proximate the edges of theunderside251 at locations where vents, such asvents36, may exist on a dam, such asdam35, wherein the dam is along a perimeter of a substrate configured to be bonded to another substrate placed byrobotic placement machine200. The UV wands245 may stabilize UV material used as dam and/or fill material, and may function when therobotic placement machine200 has placed a substrate onto another substrate having a dam, wherein the bonding may disrupt the dam material. Embodiments ofrobotic placement machine200 may also include aheight sensor274 to detect a surface height of a substrate.Height sensor274 may share the same function and structure asheight sensor74, described supra. Further embodiments ofrobotic placement machine200 may include avision system279 to detect an orientation of components associated with therobotic placement machine200. Thevision system279 may share the same function and structure asvision system79, described supra. 
- With reference toFIGS. 1-23, a first method of optical bonding is now described. The method of optical bonding may include the steps of dispensing afill material5 across a surface of thefirst substrate10 to achieve a largest fill height, h, proximate arear edge12 of thefirst substrate10 and a lowest fill height, h, proximate afront edge11 of thefirst substrate10, placing asecond substrate20 into contact with thefill material5 proximate therear edge12 of thefirst substrate10 at an angle relative to thefirst substrate10, and controllably lowering thesecond substrate20 onto thefirst substrate10 until thesecond substrate20 is bonded to thefirst substrate10 to prevent and eliminate air bubbles between the first andsecond substrates10,20. Further steps may include tracing providing afirst substrate10, dispensing dam material around a perimeter of thefirst substrate10 to form a dam35 (although some embodiments of the method may not include forming a dam; the frame may act as a dam), the dam material with aUV wand45 to stabilize the dam material, treating the surface of thefirst substrate10 with atreatment head53 prior to dispensingfill material5 onto the surface of thefirst substrate10, locating and aligning thesecond substrate20 for placement ontofirst substrate10, locating therear edge12 of thefirst substrate10 with aheight sensor74, and placing the bonded substrates into a cure oven. 
- Referring again toFIGS. 1-23, a second method of optical bonding is now described. The method of optical bonding may include the steps of dispensing afill material5 across a surface of thefirst substrate10 to achieve a largest fill height, h, proximate amiddle portion13 of thefirst substrate10, placing asecond substrate20 into contact with thefill material5 proximate themiddle portion13 of thefirst substrate10 substantially parallel or parallel to thefirst substrate10, and controllably lowering thesecond substrate20 onto thefirst substrate10 until thesecond substrate20 is bonded to thefirst substrate10 to prevent and eliminate air bubbles between the first andsecond substrates10,20. Further steps may include tracing providing afirst substrate10, dispensing dam material around a perimeter of thefirst substrate10 to form a dam35 (although some embodiments of the method may not include forming a dam; the frame may act as a dam), the dam material with aUV wand45 to stabilize the dam material, treating the surface of thefirst substrate10 with atreatment head53 prior to dispensingfill material5 onto the surface of thefirst substrate10, locating and aligning thesecond substrate20 for placement ontofirst substrate10, locating arear edge12 of thefirst substrate10 with aheight sensor74, and placing the bonded substrates into a cure oven. 
- While this disclosure has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the present disclosure as set forth above are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention, as required by the following claims. The claims provide the scope of the coverage of the invention and should not be limited to the specific examples provided herein.