Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C63/00—Lining or sheathing, i.e. applying preformed layers or sheathings of plastics; Apparatus therefor
  • B29C63/0004—Component parts, details or accessories; Auxiliary operations
  • B29C63/0013—Removing old coatings
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/26—Processing photosensitive materials; Apparatus therefor
  • G03F7/34—Imagewise removal by selective transfer, e.g. peeling away

Definitions

• This invention relates to methods and apparatus for peeling or otherwise removing media from substrates.
• Particular embodiments of this invention are provided in imaging machines, where media incorporating donor material are imaged to impart donor material onto substrates and, after imaging, are removed from the substrates.
• Color displays such as liquid crystal displays and the like, typically incorporate color filters used to provide pixels with color.
• One technique for fabricating color filters involves a laser-induced thermal transfer process.
• a particular prior art thermal transfer process is illustrated schematically in Figure IA.
• a substrate 10 (often referred to as a "receiver element") is overlaid with a donor element 12
• Donor sheet (often referred to as a "donor sheet").
• substrate 10 is typically made of glass and has a generally planar shape.
• Donor element 12 is typically a sheet which is relatively thin and relatively flexible when compared to substrate 10.
• Donor element 12 may be made of plastic, for example.
• Donor element 12 incorporates donor material (not shown).
• the donor material may comprise a colorant, a pigment or the like used to fabricate the color filter.
• Donor element 12 is image -wise exposed to selectively transfer donor material from donor element 12 to substrate 10.
• Some exposure methods involve controlling a radiation source to emit radiation beams.
• one or more controllable lasers 14 are employed to provide one or more corresponding laser beams 16.
• laser beam(s) 16 induce the transfer of donor material from the imaged regions of donor element 12 to corresponding regions of substrate 10.
• Controllable laser(s) 14 may comprise diode laser(s) which are relatively easy to modulate, have relatively low cost and have relatively small size. Such laser(s) 14 are controllable to directly image-wise expose donor element 12.
• masks (not shown) are used to image-wise expose donor element 12.
• a first donor element 12 may be used to apply red colorant to substrate 10
• a second donor element 12 may be used to apply green colorant
• a third donor element 12 may be used to apply blue colorant.
• a given imaged donor element 12 is removed from substrate 10 prior to application and use of a subsequent donor element 12.
• donor element 12 is removed from substrate 10 using a roller 18 incorporating one or more suction features 20.
• Roller 18 is brought into proximity of edge 12A of donor element 12 (as shown by arrow 19) and then suction is applied through suction features 20, such that edge 12A of donor element 12 is secured to suction features 20.
• Roller 18 is then rotated (as shown by arrow 22) and translated (as shown by arrow 24) to wind donor element 12 off of substrate 10 and onto the circumferential surface 18A of roller 18 to thereby peel donor element 12 from substrate 10.
• FIG. 1B shows a portion of donor element 12 positioned on top of substrate 10. A region of the donor element 12 has been exposed to form an imaged region 25. Imaged region 25 is separated from non-imaged region 27 by imaged edge 25 A.
• donor material may not remain evenly distributed along a region of substrate 10 corresponding to imaged edge 25 A. Rather, the amount of donor material that remains transferred to this region can be less than desired and the distribution of the transferred donor element along this region can be uneven. This can lead to the formation an edge 25B which includes fractures and other various discontinuities. These fractured edges can result in objectionable visual artifacts in the final image. In addition, donor material can also extend into non- imaged region 27, which is also undesirable.
• the present invention relates to a method for imaging a media.
• the media is placed on a support which supports a substrate and the media in a layered configuration.
• An imaging head is operated to image the media by directing radiation beams towards a surface of the imaged media while effecting relative movement between the imaging head and the support.
• a roller such as, for example, an idler roller, is brought into contact with the imaged media.
• the roller can be brought into contact with an un-imaged region of the surface of the imaged media, the un-imaged region corresponding to a region of the surface of the imaged media that is not impinged by the radiation beams.
• the un-imaged region could be an edge portion of the media.
• the roller is rotatable about an axis of rotation. Relative movement is effected between the axis of rotation of the roller and the support to cause the roller to roll along a rolling direction on the regions of the surface of the imaged media impinged by the radiation beams.
• the roller can be caused to roll on the surface of the imaged media along a direction that leads away from the edge portion.
• the imaged media is then removed from the substrate.
• the imaged media can be removed by wrapping a portion of the imaged media over a portion of a cylindrical surface of the roller while peeling the imaged media from the substrate.
• the peeling direction can be in the same direction as, or an opposite direction to, the rolling direction.
• the rolling direction can be, but is not necessarily, parallel to the scan direction, a conveyance direction of the support or a direction of a stripe feature formed on the substrate.
• an additional media can be placed on the substrate on the support in layered configuration. The additional media can be imaged while effecting relative movement between the imaging head and the support. The imaged additional media can then be removed from the substrate while effecting relative movement between the axis of rotation of the roller and the support.
• a take up roller can be used to spool a portion of the imaged media while not rolling the take-up roller on the surface of the media. A portion of the imaged media can be spooled onto the take-up roller while removing the imaged media from the substrate.
• a brake such as, for example, a magnetic particle brake or other suitable brake is used to selectively apply drag to the roller while rolling the roller on a portion of the surface of the imaged media.
• a method for imaging a media includes providing a support for supporting a substrate and the media in a layered configuration.
• An imaging head is operated to emit radiation beams towards the media to image the media while the media and the substrate are in the layered configuration.
• a roller is brought into contact with a surface of the imaged media.
• Drag such as, for example, rotational drag, is selectively applied to the roller while rolling the roller on the surface of the imaged media.
• the drag can be applied with a brake or can be applied by activating an actuator.
• the imaged media is removed from the substrate.
• the roller can be rolled on the surface of the imaged media prior to, or at the same time as, the imaged media is peeled from the substrate.
• the roller can be rolled along a plurality of different directions on the surface of the imaged media and the drag can be selectively applied in different amounts, at different times, to the roller as the roller is rolled on the surface along each of the directions.
• the roller can be rolled on the surface of the imaged media while maintaining the imaged media and the substrate in the layered configuration.
• the roller can be rolled on the surface of the imaged media while peeling the media from the substrate.
• a contact roller can roll on the surface imaged media and a portion of the imaged media can be wrapped over a portion of a surface of the contact roller while peeling the imaged media from the substrate.
• a take-up roller can be used to spool a portion of the imaged media while not rolling the take-up roller on the surface of the imaged media.
• the portion of the imaged media can be spooled onto the take-up roller while peeling the imaged media from the substrate.
• a substrate is supported on a support.
• a donor element is positioned on the substrate after supporting the substrate on the support.
• An imaging head is operated to image the donor element by directing radiation beams towards the donor element.
• a roller which is rotatable about an axis of rotation, is brought into contact with a surface of the imaged donor element.
• a plurality of relative movements are effected between the axis of rotation of the roller and the imaged donor element to cause the roller to roll on one or more imaged regions of the imaged donor element a plurality of times.
• the roller can be rolled in the same direction or different directions each time it is rolled on the one or more imaged regions. Differing amounts of drag can be applied, with a brake or other device, to the roller as roller rolls on the one or more imaged regions of the imaged donor element during one relative movement between the axis of rotation of the roller and the imaged donor element than during another relative movement between the axis of rotation of the roller and the imaged donor element.
• the imaged donor element is removed from the substrate during a relative movement between the axis of rotation of the roller and the imaged donor element.
• the substrate is removed from the support after the imaged donor element is removed from the substrate.
• the substrate is not removed from the support during any relative movement of the plurality of relative movements between the axis of rotation of the roller and the imaged donor element.
• a second donor element can be positioned on the substrate and imaged. The second donor element can be removed from the substrate while effecting relative movement between the axis of rotation of the roller and the imaged second donor element.
• an apparatus for imaging media which includes a support adapted to support a substrate and the media in a layered configuration.
• An imaging head is adapted to emit radiation beams towards the media to image the media.
• a roller is provided and a brake is adapted to selectively apply drag to the roller.
• a chassis supports the roller such that the roller is rotatable relative to the chassis.
• a controller which can include one or more controllers, is configured to operate the imaging head to emit the radiation beams towards the media.
• the controller effects relative movement between the chassis and the support to bring the roller in the vicinity of the imaged media while the imaged media and the substrate are in the layered configuration.
• the controller also effects a plurality of relative movements between the chassis and the support to cause the roller to roll on a surface of the imaged media a plurality of times.
• the controller can control the brake to selectively vary the drag applied to the roller between one relative movement between the chassis and the support and another relative movement between the chassis and the support.
• Figure IA shows a prior art thermal transfer process in which an imaged donor element is peeled from a substrate
• Figures IB and 1C shows the formation of edge discontinuities when an imaged donor element is conventionally peeled from a substrate
• Figure 2A schematically shows a plan view of an image forming system according to an example embodiment of the invention
• Figure 2B schematically shows a partial cross-sectional view of the imaging system of Figure 2A
• Figure 2C schematically shows rolling a contact roller on an imaged donor element prior to the removal of the imaged donor element from a substrate as per an example embodiment of the invention
• Figures 2D, 2E and 2F schematically show a series of operations employed by a sheet removal apparatus to remove the donor element of Figure 2C as per an example embodiment of the invention
• Figure 3 shows a flow chart representing method according to an example embodiment of the invention.
• Figure 4 shows a schematic force diagram representing the motion of a contact roller as it rolls on an imaged donor element supported by a substrate.
• Figure 3 shows a flow chart representative of a method for removing an imaged media that is supported on a substrate as per an example embodiment of the invention.
• the various steps illustrated in Figure 3 are described with reference to an apparatus 100, portions of which are shown in Figures 2A - 2F according to an example embodiment of the invention. This is for the purpose of illustration only and other suitable image forming apparatus can be used with the present invention.
• the media is processed to form an image.
• the image is formed by imaging techniques (i.e. also known as exposure techniques). Imaging techniques can employ beams of radiation (e.g. laser beams) to form an image on a surface. These images can be formed in various ways.
• imaging techniques can be used to change a property or characteristic of an image modifiable layer to form an image thereon.
• Imaging techniques can be used to ablate a surface to form an image thereon.
• Imaging techniques can be used to facilitate a transfer of donor material to a surface to form an image thereon.
• Imaging head 102 comprising a radiation source (not shown) such as a laser is provided to transfer donor material (also not shown) from a donor element 112 to a surface of substrate 110 (shown in broken lines in Figure 2A).
• Imaging head 102 can include one or more channels 114.
• imaging head 102 includes an arrangement of channels 114; each of the channels 114 being individually controllable to emit radiation beams 116 (not shown in Figure 2A).
• Imaging head 102 is operated to direct the radiation beams 116 to impinge on various regions of donor element 112.
• Imaging electronics 103 control the emission of radiation beams 116 from channels 102 in accordance with image data 104 provided by controller 108.
• imaging head 102 In this illustrated embodiment, substrate 110, imaging head 102, or a combination of both, are moved relative to one another while channels 114 are controlled in response to image data 104 to scan the radiation beams 116 over donor element 112 in an image-wise fashion.
• imaging head 102 is stationary and substrate 110 is moved.
• substrate 110 is stationary and imaging head 102 is moved.
• both the imaging head 102 and substrate 110 are moved.
• imaging head 102 exposes donor 112 in a step and repeat fashion. In these embodiments, relative movement between imaging head 102 and donor element 112 can occur between shots of exposure.
• donor element 112 can be too large to be imaged within a single exposure or scan. Multiple exposures or scans of imaging head 102 can be required to complete an image.
• FIG. 1 shows a schematic plan view of the image forming systems of apparatus 100.
• a support 101 is provided for supporting substrate 110 and donor element 112 in a layered configuration.
• support 101 is adapted to convey substrate 110 and donor element 112 along a path aligned with main-scan axis 42.
• support 101 is movable along a plurality of conveyance directions (i.e. forward direction 42A and reverse direction 42B).
• Forward direction 42A is opposite to reverse direction 42B.
• Support 101 can reciprocate between forward direction 42 A and reverse direction 42B.
• Imaging head 102 is movably supported on support 105 which straddles support 101.
• imaging head 102 is movable along a path aligned with sub- scan axis 44. In this embodiment, imaging head 102 can move along away direction
• imaging head 102 can bi-directionally scan radiation beams 116 over donor element 112 to form an image. Bidirectional scanning techniques can enhance imaging productivity since scans can be made in each of the opposing scan directions.
• Motion system 109 is provided to cause the motion of support 101 and/or imaging head 102 and can include suitable drives, transmission members and/or guide members. Motion system 109 can include one or more motion systems. Those skilled in the art will realize that separate motion systems can also be used to operate different systems within apparatus 100. Controller 108, which can include one or more controllers is used to control one or more systems of apparatus 100, including but not limited to, motion system 109. Controller 108 can cause image data 104 to be transferred to imaging head 102 and control the imaging head to emit radiation beams 116 in accordance with this data. Controller 108 may also control systems other than apparatus 100.
• Controller 108 may be configured to execute suitable software and may include one or more data processors, together with suitable hardware, including by way of non- limiting example: accessible memory, logic circuitry, drivers, amplifiers, A/D and D/ A converters, input/output ports and the like. Controller 108 may comprise, without limitation, a microprocessor, a computer-on-a-chip, the CPU of a computer or any other suitable microcontroller. Controller 108 can be associated with a materials handling system.
• FIG. 2 B shows a schematic partial cross-sectional view of the image forming systems of apparatus 100.
• substrate 110 can be secured to support 101 by a variety of techniques known in the art (e.g. suction).
• donor element 112 is positioned in a layered configuration with substrate 110 in which donor element 112 is laid on substrate 110 after substrate 110 is supported on support 101.
• support 101 comprises stands 118 which are transversely spaced apart from the edges of substrate 110 and which have heights that are substantially similar to the thickness of substrate 110.
• Support 101 also comprises one or more suction features 120 which apply suction in the spaces 122 between stands 118 and substrate 110. This suction secures donor element 112 to substrate 110. It will be appreciated by those skilled in the art that there are other additional and/or alternative techniques for securing donor element 112 to substrate 110 and the invention should be understood to accommodate such additional and/or alternative donor element securing techniques.
• the transfer of donor material from donor element 112 to substrate 110 may be implemented using a variety of laser-induced thermal transfer techniques, for example.
• laser-induced thermal transfer processes used by the invention include: laser-induced “dye transfer” processes, laser-induced “melt transfer” processes, laser- induced “ablation transfer” processes, and laser-induced “mass transfer” processes.
• the make-up of substrate 110, donor element 112, and the donor material depend on the particular imaging application.
• imaging apparatus 100 is used to fabricate color filters for displays on substrate 110.
• substrate 110 is typically made of a transparent material (e.g. glass)
• donor element 112 is typically made of plastic and the donor material typically comprises one or more colorants.
• colorants may include suitable dye-based or pigment-based compositions, for example.
• the donor material may also comprise one or more suitable binder materials.
• imaging head 102 is constrained to emit radiation beams 116 such that they impinge various areas of imaged region 112B of donor element 112. Consequently, region 112A of donor element 112 remains as a non-imaged area, and may in some cases provide a border around imaged region 112B. Accordingly, in the illustrated embodiment, donor material is only transferred from donor element 112 onto imaged region HOB of substrate 110 and not onto the non-imaged region HOA of substrate 110. In the illustrated embodiment, portions 113 of non-imaged region 112A overhang substrate 110 and are supported by stands 118. At the conclusion of the imaging process, donor element 112 is removed from substrate 110. In this example embodiment, it is desired that donor element 112 be removed from substrate 110 in a manner that reduces the presence of fractures and other discontinuities at the edges of various features that are formed on substrate 110.
• FIG. 2C is a schematic partial side view depicting one end of support 101, substrate 110 and imaged donor element 112.
• sheet removal apparatus 129 comprises a chassis 136 and a plurality of rollers (i.e. contact roller 130 and take-up roller 132) which are mechanically coupled to chassis 136 by a corresponding pair of roller couplings (contact roller coupling 138 and take- up roller coupling 140).
• Rollers 130, 132 are preferably substantially cylindrical in shape.
• Contact roller coupling 138 and take-up roller coupling 140 permit their respective rollers 130,
• take-up roller coupling 140 comprises an actuator 133 which effects movement of the axis 132A of take-up roller 132 with respect to chassis 136.
• Take-up roller axis-position actuator 133 is referred to herein as the "take-up roller axis-position actuator 133".
• Take-up roller axis-position actuator 133 may be controlled by controller 108 using signal 135.
• Take-up roller axis-position actuator 133 may generally comprise any suitably coupled actuator.
• Non-limiting examples of actuators which may be used to provide take-up roller axis-position actuator 133 include suitably coupled electric motors and/or pneumatic actuators.
• take-up roller coupling 140 also comprises a take-up roller rotational actuator 139 which causes rotation of take-up roller 132 about its axis 132A.
• Take-up roller rotational actuator 139 may be controlled by controller 108 using signal 141.
• take-up roller rotational actuator 139 comprises a suitably coupled motor, but take-up roller rotational actuator 139 may generally comprise any suitably configured actuator.
• take-up roller 132 also comprises one or more suction features 134.
• Suction features 134 may comprise orifices coupled in fluid communication to a source of suction 143.
• suction source 143 may comprise a mechanism for creating a positive or negative pressure differential, such as a suitably configured pump or the like.
• Suction source 143 may be controlled by controller 108 using signal 145 which may also control one or more valves or similar components (not shown) related to the application of suction by suction source 143.
• contact roller 130 is a non-driven "idler" roller. In alternative embodiments, contact roller 130 may be rotationally driven.
• Sheet removal apparatus 129 also comprises one or more chassis-position actuators 131 which cause relative movement between support 101 and chassis 136. Relative movement between support 101 and chassis 136, results in corresponding movement between support 101 and rollers 130 and 132.
• chassis- position actuators 131 cause movement of chassis 136 relative to support 101 to effect relative movement between support 101 and chassis 136.
• chassis-position actuators 131 cause movement of support 101 relative to chassis 136 to effect relative movement between support 101 and chassis 136.
• Chassis-position actuators 131 may generally comprise any one or more suitably coupled actuators.
• Non-limiting examples of actuators which may be used to provide chassis-position actuators 131 include, suitably coupled electric motors and/or pneumatic actuators.
• controller 108 uses signal to cause chassis-position actuators 131 to create relative movement between chassis 136 and support 101, such that chassis 136 and the rest of sheet removal apparatus 129 are positioned in the vicinity of one edge portion 115A of donor element 112 (see Figure 2C).
• sheet removal apparatus 129 approaches donor element 112 from a vertical direction.
• chassis-position actuators 131 cause sheet removal apparatus 129 to approach donor element 112 (or donor element 112 to approach sheet removal apparatus 129) from other directions.
• step 310 sheet removal apparatus 129 moves toward donor element 112 until contact roller 130 makes contact with donor element 112.
• contact roller 130 contacts donor element 112 in non-imaged region 112A (i.e. outside of imaged region 112B).
• This positioning of the contact between contact roller 130 and donor sheet 112 avoids an impact of contact roller 130 in imaged region 112B of donor element 112 and prevents any corresponding degradation of the image in corresponding imaged region 11OB of substrate 110 that can result from such an impact.
• take-up roller 132 has not been brought into contact with donor element 112.
• take-up roller axis-position actuator 133 is controlled to cause take-up roller 132 to not contact donor element 112.
• contact roller 130 is rolled on the surface of a portion of imaged donor element 112.
• contact roller 130 is rolled on a portion of imaged donor element 112 that includes imaged region 112B.
• contact roller 130 is rolled on the regions of donor element 112 that were impinged by radiation beams during step 300.
• contact roller 130 is rolled along a path that extends from non- imaged region 112A in the vicinity of the edge portion 115A over imaged region 112B to non-imaged region 112A in the vicinity of edge portion 115B.
• Controller 108 uses signal 137 to cause chassis-position actuators 131 to move chassis 136 (including rollers 130, 132) along a rolling direction (as shown by arrow 148A) to cause contact roller 130 to roll on the supported donor element 112.
• contact roller 130 rotates (as shown by arrow 144) as it is rolled on imaged donor element 112. As shown in Figure 2C, this causes the rotation axis 130A of contact roller 130 to move along the direction of arrow 148A.
• Figure 2C shows that contact roller 130 is rolled on the imaged donor element 112 while imaged donor element 112 and substrate 110 remain positioned in their layered configuration.
• the inventors have surprisingly determined that rolling a roller such as contact roller 130 on the imaged donor element 112 can be used to reduce the presence of artifacts such as edge discontinuities when imaged donor element 112 is subsequently removed from substrate 110.
• the inventors have discovered that rolling the imaged donor element 112 prior to its removal from substrate 110 can lead to a reduced fracturing of the donor material at the edges of imaged features, especially when donor element 112 is peeled from substrate 110.
• one possible cause for the improved visual characteristics of the formed images may arise from the presence of "micro-slippage" between imaged donor element 112 and substrate 110 as contact roller 130 is rolled on imaged donor element 112.
• Figure 4 illustrates a schematic force diagram representing the motion of contact roller 130 as it rolls on supported donor element 112. With the exception of interface force F, all of the forces and moments are shown acting on contact roller 130.
• the forces acting on contact roller 130 include the load W exerted on contact roller 130.
• Load W can include a force exerted on contact roller 130 by chassis-position actuators 131.
• Force P represents the force required to move contact roller on the surface of the supported donor element 112 along direction of arrow 148A and in this illustrated embodiment is provided by chassis-position actuators 131.
• Couple M represents the frictional resistance or drag that is exerted on contact roller and opposes rotational direction of arrow 144.
• Contact roller 130 can include a compliant surface which can lead to various deformations at the point of contact between the roller 130 and the supported donor element 112. Such a deformation is shown at area 170 in Figure 4. These deformations cause contact between contact roller 130 and donor element 112 to take place not at a single contact line but rather, over a certain area which can give rise to "rolling resistance". Although the deformation shown in Figure 4 is confined to contact roller 130, it is to be understood that deformation can also occur on the surface that the roller rolls along.
• Figure 4 shows that the resultant of the forces applied over this area by supported donor element 112 on contact roller 130 is reaction force R which is applied at point 171.
• Point 171 is not located directly underneath the rotation axis 130A, but slightly in front of it.
• Point 171 is displaced from center of rotation 172 by distance b.
• Distance b is known in the art as the coefficient of rolling resistance. It is to be noted however that b is not a dimensionless coefficient since it is expressed in units of length.
• a component of reaction force R is the friction force fi between contact roller 130 and supported donor element 112.
• An interface force F also exists between donor element 112 and substrate 110.
• the radius of contact roller 130 is shown as "r".
• a summation of the moments acting on contact roller 130 about point 171 may be expressed by the following relationship (i.e. assuming the roller is moving with a constant speed):
• Interface force F is dependant on various factors which can include the hold down force between imaged donor element 112 and substrate 110 (e.g. an applied suction between donor element 112 and substrate 110), load W and various frictional parameters pertaining to the donor element-to-substrate interface. Other factors can include the shear forces that must be overcome to shear the donor material at the boundaries of various image features that are formed.
• donor material at the boundaries of imaged features may shear as friction force fi causes a localized shearing of imaged donor element 112 in the vicinity of the imaged feature boundaries.
• the localized shearing of the donor material may in turn reduce the amount of fracturing that can occur at the imaged feature boundaries when imaged donor element 112 is peeled from substrate 110.
• the inventors have found that rolling contact roller 130 across imaged region 112A noticeably promotes reduction of artifacts along the edges of the features formed in imaged region HOB of substrate 110 when imaged donor element 112 is removed from substrate 110. Friction force fi may be increased to desired levels in various ways.
• Relationship (3) suggests that friction force fi can be increased by increasing load W or by employing contact rollers 130 having a reduced radius r. This can be done in various embodiments of the invention while in other embodiments of the invention various factors may limit the extent of allowable changes associated with these parameters. For example, excessive increases in load W may lead to contact stresses sufficient for damaging the donor material that has been transferred to substrate 110 thereby reducing the visual quality of the final image. Reducing the size of contact roller 130 may lead to undesirable deflections in the roller which can adversely impact the ability of contact roller 130 to uniformly roll over donor element 112. Reducing the size of contact roller 130 may also promote the aforementioned contact stress problems. Increase in load W may also increase interface force F.
• contact roller 130 includes material or geometry that gives rise to a coefficient of rolling resistance b sufficient to achieve a desired image quality once the imaged donor element 112 is peeled from substrate 110.
• various frictional attributes between contact roller 130 and donor element 112 are adjusted to achieve a desired image quality. These frictional attributes can include adjusting material properties of one or both of contact roller 130 and donor element 112 to change associated coefficients of friction, for example.
• Relationship (3) also suggests that friction force fi can also be increased by increasing the drag created by couple M.
• a brake 200 is employed to selectively adjust the drag on contact roller 130 to a desired level suitable for reducing artifacts such as the aforementioned edge discontinuities.
• Brake 200 is controlled by signal 201 to selectively apply a desired amount of drag to contact roller 130 as it is rolled over the surface of supported donor element 112.
• Brake 200 can be actuated by various actuators controlled by signal 201.
• the use of brake 200 can be particularly advantageous especially in applications in which contact roller 130 performs various different functions.
• the amount of drag applied to contact roller as required by a specific function can be easily tailored by appropriately activating brake 200 in accordance with the desired amount of drag required by that function.
• brake 200 can be selectively activated as per the requirements of a particular function required of contact roller 130 thereby allowing contact roller 130 to perform different functions.
• one of the functions of brake 200 is to selectively apply a sufficient amount of drag to contact roller 130 during step 320 to improve visual qualities of the formed imaged when imaged donor element 112 is subsequently removed from substrate 110.
• contact roller 130 is controlled to roll along a rolling direction that is substantially parallel to a direction that donor element 112 is subsequently peeled along to remove donor element 112 from substrate 110.
• debris created by the braking action of brake 200 is not desired in particular applications (e.g. the formation of color f ⁇ lters in clean room environments).
• brakes 200 that minimize the generation of such debris are preferred.
• Such brakes can include magnetic particle brakes and hysteresis brakes, for example.
• brake 200 is selectively controlled to apply rotational drag to contact roller 130.
• drag can be selectively used in other ways.
• contact roller 130 can be a driven roller which is controlled to move chassis 136 as the contact roller 130 is driven to roll over imaged donor element 112.
• Various actuators can be controlled to selectively apply forces that restrict the movement of chassis 136.
• Various actuators can be controlled to selectively apply linear drag forces to chassis 136.
• contact roller 130 is rolled along a rolling direction (i.e. the direction of arrow 148A in Figure 2C) that is substantially parallel to direction of movement that support 101 was conveyed along during the image forming step 300.
• the rolling direction is substantially parallel to main-scan axis 42.
• the rolling direction can be substantially parallel to a direction that the radiation beams were scanned along during the imaging of donor element 112.
• patterns of features can be imaged during step 300.
• the imaged features in the patterns can repeat along one or more directions and contact roller 130 can be controlled to roll along a rolling direction that is substantially parallel to one of these one or more directions.
• patterns of continuous stripe features or interrupted stripe features can be imaged during step 300.
• Contact roller 130 can be controlled to roll along a rolling direction that is substantially parallel to a direction in which the continuous or interrupted stripe features extend along.
• the various imaged features formed in step 300 may be formed with an orientation that is selected in accordance with a particular rolling direction that contact roller 130 is subsequently rolled along.
• a particular orientation of the imaged features can be selected to facilitate improved visual qualities in the final image when the contact roller 130 is rolled on donor element 112 and donor element 112 is subsequently removed from substrate 110.
• Imaged donor element 112 is removed from substrate 110 in step 330.
• donor element 112 is removed after contact roller 130 has rolled across imaged region 112B to un-imaged region 112A in the vicinity of edge portion 115B.
• signal 135 causes take-up roller axis-position actuator 133 to move take-up roller 132 into the vicinity of imaged donor element 112.
• take-up roller 132 moves into the vicinity of non-imaged region 112A of donor element 112 at a location that is further from imaged region 112B than the location of contact roller 130. In this illustrated embodiment, take-up roller 132 moves into the vicinity of portion 113 of non-imaged region 112 A. In currently preferred embodiments, take-up roller 132 moves into the vicinity of portion 113 at a location which at least partially overlies stand 118. In some embodiments, take-up roller 132 moves into the vicinity of non-imaged region 112A at a location that is spaced further from the edge of substrate 110 than suction features 120 which secure donor element 112 to substrate 110.
• controller 108 uses signal 145 to cause suction source 143 to apply suction through suction features 134.
• the application of suction through suction features 134 causes a portion of non- imaged region 112A (including edge portion 115B) to adhere to take-up roller 132 (i.e. suction features 134 secure a portion of non-imaged region 112A to take-up roller 132).
• take-up roller 132 contacts donor element 112 in non- imaged region 112A and suction is applied directly to secure donor element 112 to take-up roller 132.
• take-up roller 132 need not contact donor element 112 before suction is applied.
• controller 108 may turn off or reduce the suction applied by suction features 120 prior to or during the application of suction through suction features 134.
• suction features 134 are located in one or more known locations on the cylindrical surface of take-up roller 132.
• controller 108 preferably uses signal 141 to operate take-up roller rotational actuator 139 in a "position mode". In position mode operation, controller 108 uses a control technique which causes actuator 139 to move take-up roller 132 at any velocity (within its controllable velocity range) to achieve a desired position.
• take-up roller 132 is a position where suction features 134 are located proximate to donor element 112.
• take-up roller 132 is shown as having suction features in only one circumferential location on its cylindrical surface.
• take-up roller 132 may comprise suction features at a plurality of circumferential locations on its cylindrical surface.
• Figure 2E shows that once edge portion 115B of donor element 112 is secured to the cylindrical surface of take-up roller 132, controller 108 uses signal 135 to cause take-up roller axis-position actuator 133 to move take-up roller 132 away from substrate 110 (i.e. in a direction that has at least a component in the direction of arrow 146).
• take-up roller axis-position actuator 133 causes movement of take-up roller 132 with respect to chassis 136 and with respect to contact roller 130 while chassis 136 and contact roller 130 remain in the same positions.
• Edge portion 115B of donor element 112 and possibly some of non-imaged region 112A move away from support 101 when take-up roller 132 moves in this manner.
• contact roller 130 preferably remains in contact with, and may exert force against, donor element 112. Consequently, a portion of donor element 112 on one side of contact roller 130 (i.e. the side away from take-up roller
• the effective area of contact between contact roller 130 and donor element 112 is less than 10% of the circumferential surface area of contact roller 130. In other embodiments, this ratio is less than 5%. In some embodiments, the force applied between contact roller 130 and donor element 112 is less than the force of gravity acting on contact roller 130 (i.e. chassis 136 supports some of the weight of contact roller 130).
• the movement of take-up roller 132 away from substrate 110 may also comprise movement of take-up roller 132 in one or more directions that are tangential to substrate 110.
• take-up roller axis position actuator 133 may cause take-up roller 132 to move on a curved path.
• controller 108 may use signal 141 to cause take-up roller rotational actuator 139 to pivot take-up roller 132 about its axis 132A.
• Such pivotal motion of take-up roller 132 can be used to take-up any slack in the portion of imaged donor element 112 which has been peeled from substrate 110 or to otherwise track a desired tension on this portion of imaged donor element 112.
• controller 108 may use signal 141 to control take-up roller rotational actuator 139 in "torque mode".
• torque mode operation controller 108 uses a control technique which causes actuator 139 to move take-up roller 132 at any velocity (within its controllable velocity range) to track a desired torque.
• peel angle ⁇ is less than thirty (30) degrees depending in part on the media (i.e. the donor material, substrate 110 and donor element 112). In currently preferred embodiments, peel angle ⁇ is less than five (5) degrees.
• controller 108 uses signal 137 to cause chassis- position actuators 131 to move chassis 136 (including rollers 130, 132) in the direction of arrow 148B and uses signal 141 to cause take-up roller rotation actuator 139 to simultaneously rotate take-up roller 132 with respect to chassis 136 and support 101 in the direction of arrow 147.
• This simultaneous movement of chassis 136 and rotation of take-up roller 132 pulls donor element around contact roller 130 and peels donor element 112 from substrate 110.
• Contact roller 130 rotates in the direction of arrow 146 as it is rolled on imaged donor element 112 along a peeling direction (i.e. along the direction of arrow 148B.
• this rotation causes the rotation axis 130A of contact roller 130 to move along the direction of arrow 148B.
• the direction of arrow 148B is opposite to the direction of arrow 148A that contact roller 130 was rolled along in step 320.
• the peeling direction associated with the movement of contact roller 130 during step 330 is opposite to the rolling direction associated with the movement of contact roller 130 during step 320.
• controller 108 uses signal 141 to operate take-up roller rotational actuator 139 in a "torque mode", where controller 108 causes take-up roller 132 to rotate at any velocity (within its controllable velocity range) to achieve a desired torque.
• take-up roller rotational actuator 139 operates in torque mode to track this desired torque, the peeling tension on donor element 112 is maintained relatively close to the desired peeling tension.
• controller 108 uses signal 141 to operate take-up roller rotational actuator 139 in a "position mode” to track a position that is synchronized with the translational position of chassis 136.
• donor element 112 is "spooled up" by (i.e. winds around the cylindrical surface of) take-up roller 132.
• Contact roller 130 remains in contact with the portion of donor element 112 which is still on substrate 110 and may apply a force against donor element 112.
• contact roller 130 is an idler roller.
• Contact roller 130 prevents donor element 112 from separating prematurely from substrate 110 and ensures that donor element 112 is separated from substrate 110 at the desired peel angle ⁇ .
• brake 200 is controlled to apply a different amount of drag to contact roller 130 as the contact roller is rolled on the surface of imaged donor element 112 during the separation and removal of imaged donor element 112 from substrate 110 than during the post imaging rolling sequence corresponding to step 320. That is, a plurality of relative movements between the rotation axis 130A of contact roller 130 and imaged donor element 112 and support 101 were enabled to cause contact roller to roll over imaged region 112B a plurality of times (i.e. in steps 320 and 330). During one of the plurality of relative movements, donor element 112 was removed from substrate 110 by the peeling method described. In this illustrated embodiment, brake 200 was selectively controlled to apply different amounts of drag to contact roller 130 during each of the relative movements.
• Different amounts of the selectively applied drag can include larger or smaller amounts of drag than the amount of drag that was applied in step 320.
• brake 200 is controlled to apply less drag during step 330 than during step 320. In this embodiment, substantially no additional drag to contact roller 130 was applied by brake 200 during the removal of donor element 112 from substrate 110. It is to be noted however, that brake 200 may provide some form of minimal drag even when un-actuated. Brake 200 can be actuated to apply varying amounts of drag for varying durations to contact roller 130 and these amounts and durations can vary in accordance with a requirement of an application involving contact roller 130. Brake 200 can be controlled to selectively apply different amounts of drag to contact roller 130 at various positions along a path that contact roller 130 is rolled along.
• Print-through effects can arise when a donor element is wrapped around a roller as the roller is translated to peel the donor element from an underlying substrate (i.e. see Figure IA). Since the media edge can have a non-negligible thickness, the edge of the media that is initially secured to the roller can cause a portion of the unpeeled donor element to exhibit a discontinuity when the secured edge is rolled over it. Since take- up roller 132 is spaced-apart from substrate 110, the image imparted onto substrate 110 is unaffected when the portion of donor sheet 112 being wound onto take-up roller 132 overlaps edge portion 115B.
• controller 108 may use signal 137 to cause chassis-position actuator 131 to move chassis 136 away from donor element 112 and may use signal 141 to cause take-up roller rotational actuator 139 to rotate take-up roller 132 so as to take-up the "tail" of donor element 112. Controller 108 may operate take-up roller rotational actuator 139 in a position mode during this portion of the donor element 112 removal process.
• a second donor element 112 (e.g. a donor element 112 of a different color) can be positioned on substrate 110 and a method similar to that taught by the invention can be employed to further image the second donor element 112 and remove the second donor element 112 when it has been imaged.
• substrate 110 is removed from support 101 in step 340.
• Donor element removal apparatus 129 need not remove substrate 110 from support 101 as other mechanisms as known in the art can be employed.
• substrate 110 is not removed from support 101 during any of the plurality of relative movements between the rotation axis 130A of contact roller 130 and imaged donor element 112 that were enabled to cause contact roller to roll over imaged region 112B a plurality of times in preceding steps.
• Pre-rolling the imaged donor element 112 prior to the removal of imaged donor element 112 from substrate 110 can be used to reduce artifacts that can arise when donor element 112 is removed from substrate 110.
• the amount of the donor material that remains transferred to the surface of the substrate 110 when the imaged donor element 112 is peeled from the substrate can be adjusted by pre-rolling contact roller 130 on imaged donor element 112 prior to its removal. Artifacts such as edge discontinuities can be reduced by this adjustment of the amount of donor material that remains transferred to the surface of the substrate.
• the inventors have found that variations in the amount and distribution of donor material that is intended to be transferred to a particular region of substrate 110 can be reduced by rolling contact roller 130 on donor element 112 prior to its removal from substrate 110 especially when the particular region is in the vicinity of an edge portion of a feature formed on substrate 110.
• rolling contact roller 130 was used in both the pre-rolling steps and the peeling steps, one skilled in the art will quickly ascertain that different rolling members can be used in each of these steps.
• Contact roller 130 can include a roller whose function is dedicated solely to the pre-rolling aspects of the invention.
• the displays can be LCD displays.
• the displays can be organic light-emitting diode (OLED) displays.
• OLED displays can include different configurations. For example, in a fashion similar to LCD display, different color features can be formed into a color filter used in conjunction with a white OLED source.
• different color illumination sources in the display can be formed with different OLED materials in various embodiments of the invention.
• the OLED based illumination sources themselves control the emission of colored light without necessarily requiring a passive color filter.
• OLED materials can be transferred to suitable media. OLED materials can be transferred to a receiver element with laser-induced thermal transfer techniques.
• chassis-position actuators 132 A rotation axis

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• 2008
  • 2008-10-02 KR KR1020107008417A patent/KR20100074201A/ko not_active Withdrawn
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  • 2008-10-02 WO PCT/US2008/078518 patent/WO2009051966A1/en not_active Ceased
  • 2008-10-02 JP JP2010530018A patent/JP2011516899A/ja active Pending
  • 2008-10-02 EP EP08839992A patent/EP2200811A1/en not_active Withdrawn
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