processing method

Abstract

The present invention discloses a method comprising: providing an assembly temporarily adhered to at least one carrier on at least one side by an adhesive element, the assembly including at least one plastic support sheet; heating the assembly while compressing the assembly and the adhesive element, wherein during heating the assembly and the adhesive element under compression, the adhesive strength of the adhesive element to the carrier and / or the assembly is partially reduced; and wherein after partially or completely removing the pressure on the assembly and the adhesive element under compression, further heating of the adhesive element can further reduce the adhesive strength of the adhesive element to the carrier and / or the assembly.

Description

[0001] This divisional application is a divisional application of Chinese Invention Patent Application No. 201780029194.X (International Application No. PCT / EP2017 / 061319), entitled "Carrier Release Technology", filed on May 11, 2017. Technical Field

[0002] The processing of the assembly may include temporarily supporting the assembly between two carriers that are releasably adhered to the assembly. Summary of the Invention

[0003] The inventors of this application have worked to improve the technology by making the carrier detach from the assembly after processing.

[0004] A method is provided comprising: providing an assembly temporarily adhered to opposite sides of an individual carrier by means of individual adhesive elements, the assembly including at least one plastic support sheet; heating the assembly while simultaneously mechanically compressing the assembly between the carriers, wherein during the heating of the assembly, the adhesion strength of one of the adhesive elements to the individual carrier and / or the assembly under mechanical compression is partially reduced; and wherein after partially or completely relieving the pressure on the assembly under mechanical compression between the two carriers, the adhesion strength of the adhesive elements to the carriers and / or the assembly can be further reduced by further heating the adhesive elements.

[0005] According to one specific embodiment, the method further includes: after partially or completely reducing the pressure on the assembly caused by mechanical compression between the two carriers, further heating the adhesive element to further reduce the adhesive strength of the adhesive element to the carrier and / or the assembly, and releasing the adhesive element from the carrier and / or the assembly.

[0006] According to one specific embodiment, partially reducing the adhesive strength of the adhesive element to the carrier and / or the assembly while mechanically compressing the assembly between the carriers comprises: creating an air pocket at the point where the adhesive element contacts the carrier and / or the assembly to reduce the contact area between the solid material of the adhesive element and the carrier and / or the assembly; and wherein further reducing the adhesive strength between the at least one adhesive element and the carrier and / or the assembly comprises: thermally expanding the solid material of the adhesive element to sever the contact between the solid material of the adhesive element and the carrier and / or the assembly at the location between the air pockets.

[0007] According to one specific embodiment, the method further includes releasing one of the carrier and the assembly from the adhesive element without releasing the other of the carrier and the assembly from the adhesive element.

[0008] According to one specific embodiment, the assembly includes a liquid crystal display component comprising two plastic support sheets and a spacer for creating a space between the two plastic support sheets to receive liquid crystal material.

[0009] According to one embodiment, the assembly includes two plastic support sheets, and the carrier is an individual plastic support sheet used to support the plastic support sheets during the processing of stacking the two support sheets together to form the assembly.

[0010] According to one embodiment, the adhesive element located on at least one side of the assembly includes a support sheet and two adhesive layers supported on the opposite side of the support sheet.

[0011] According to one embodiment, the assembly includes a plastic support sheet supporting a stack of conductors, semiconductors, and insulating layers that define an active matrix array of thin-film transistors (TFTs).

[0012] According to one embodiment, the method further includes: detaching one of the carriers from the assembly without detaching the other of the carriers from the assembly, and subsequently stripping the assembly from the other of the carriers.

[0013] According to one embodiment, the heating operation to partially reduce adhesive strength also includes curing the adhesive included in the assembly.

[0014] According to one embodiment, heating the adhesive element to partially reduce the adhesive strength includes establishing a temperature gradient covering the adhesive element and assembly, which is smaller than the minimum temperature gradient covering the adhesive element and assembly established during further heating of the adhesive element to further reduce the adhesive strength.

[0015] According to one specific embodiment, the method further includes: after heating and simultaneously mechanically compressing the assembly between the carriers, cooling the assembly while continuing to mechanically compress the assembly between the carriers; wherein during the heating and / or cooling of the assembly under mechanical compression, the adhesive strength of one of the adhesive elements to the individual carrier and / or to the assembly is partially reduced; and wherein the adhesive strength of the adhesive element to the carrier and / or to the assembly can be further reduced by further heating the adhesive element after partially or completely reducing the pressure of the assembly under mechanical compression between the two carriers.

[0016] A method is provided comprising: providing an assembly temporarily adhered to opposite sides to individual carriers via individual adhesive elements, the assembly including at least one plastic support sheet; heating the assembly and the adhesive elements while generating gas within the at least one adhesive element, while compressing the assembly between the carriers under a pressure that suppresses wrinkling of the plastic support sheet due to the heating, while maintaining the generated air pocket at the interface between the carrier and the at least one adhesive element and / or at the interface between the assembly and the at least one adhesive element.

[0017] According to one specific embodiment, the heating is performed while curing an adhesive included in the assembly, and the air bag is held at the interface(s) when the adhesive has been cured.

[0018] According to one specific embodiment, the method further includes: after at least partially relieving the pressure of the assembly compressed between the two carriers, further heating the at least one adhesive element to reduce the adhesive strength between (i) the carriers and / or the assembly and (ii) the solid material of the at least one adhesive element located around the air bag.

[0019] According to one specific embodiment, the method further includes cooling the assembly and the adhesive element, simultaneously continuously mechanically compressing the assembly between the two carriers before at least partially reducing the pressure of the assembly being mechanically compressed between the two carriers and further heating the at least one adhesive element to further reduce the adhesion strength between the carrier and / or the assembly and the solid material of the at least one adhesive element located around the air bag.

[0020] A method is also provided, comprising: providing an assembly temporarily adhered to opposite sides to an individual carrier by means of individual adhesive elements, the assembly including at least one plastic support sheet; heating the assembly to completely cure an adhesive included in the assembly, wherein the adhesive strength of the at least one adhesive element to the adjacent carrier and / or assembly is partially reduced during the heating, and can be further reduced by further heating after the adhesive included in the assembly has been completely cured.

[0021] According to one embodiment, the adhesion strength of the at least one adhesive element to the adjacent carrier and / or assembly can be further reduced by first cooling and then further heating after the adhesive included in the assembly has been fully cured.

[0022] According to one embodiment, the adhesive included in the assembly secures the two components together within the assembly. Attached Figure Description

[0023] Specific embodiments of the present invention are described below by way of example only, with reference to the accompanying illustrations, wherein:

[0024] Figure 1 The illustration shows an example of a technique according to a specific embodiment of the present invention; and

[0025] Figure 2 The illustration shows an example of a process in which an adhesive layer is released from an easy carrier. Detailed Implementation

[0026] The following description is an example of stacking two thin-film components to form a side array assembly providing a liquid crystal display (LCD) device, but the same technology is equally applicable to stacking components to form an assembly providing a single LCD device or one or more other types of devices, such as, for example, one or more encapsulated organic light-emitting device (OLED) displays containing pixels of organic light-emitting material whose light emission is controlled by an active matrix array.

[0027] refer to Figure 1 A first flexural component 8 is releasably secured to a rigid carrier 4 via an adhesive element 6. During the processing of the assembly, the adhesive strength of the first flexural component 8 to both the rigid carrier 4 and the flexural component is high enough to withstand excessive thermal expansion of the first flexural component 8, but not so high as to prevent the adhesive element 6 from peeling off from at least the assembly after processing, or (ii) can be reduced after processing of the assembly to facilitate the release of the adhesive element 6 from at least the assembly. For example, the adhesive element 6 may be a single pressure-sensitive adhesive layer, or a single adhesive layer whose adhesive strength to one or more of the first flexural component 8 and the rigid carrier 4 can be reduced by increasing the temperature (thermal release), by decreasing the temperature (cold release), or by exposure to ultraviolet (UV) radiation (UV release). The adhesive element 6 may also include two adhesive layers located on opposite sides of a support film, wherein the two layers may, for example, include any combination of a pressure-sensitive adhesive, a heat-release adhesive, a cold-release adhesive, and a UV-release adhesive.

[0028] In this example, the first flexure component 8 includes a plastic support film that supports an alignment film for controlling the orientation of liquid crystal molecules in a portion of the liquid crystal material adjacent to the alignment film, and may also support a common electrode used by the array of one or more other components, such as an LCD device, if the LCD device is of the type that is operated by electrodes located on opposite sides of the liquid crystal material by generating an electric field in the liquid crystal material.

[0029] The second flexural assembly 12 is releasably and securely attached to another rigid carrier 16 via a double-sided adhesive unit 14, the double-sided adhesive unit comprising a support film 14b supporting a thermally release adhesive layer 14c adjacent to the carrier 16 and a second adhesive layer 14a adjacent to the second flexural assembly 12. In this example, during the processing of the assembly, the adhesive strength of the second adhesive layer 14a to the second flexural assembly 12 is high enough to withstand excessive thermal expansion of the assembly, but not (i) too high to prevent the adhesive element from peeling off from the assembly after processing or (ii) able to decrease after the assembly is processed to facilitate the release of the second adhesive layer 14a from the assembly. The second adhesive layer 14a may, for example, comprise (a) a pressure-sensitive adhesive, (b) a thermally release adhesive layer having a release temperature higher than that of the first adhesive layer 14c, (c) a cold-release adhesive layer, or (d) a UV-release adhesive layer. The second flexural assembly 12 may include a plastic support film supporting: (i) a stack of conductors, semiconductors, and insulators / dielectric layers defining individual groups of active matrix circuitry for controlling the electric field within the liquid crystal medium for use in an LCD device, and (ii) a spacer structure 10 for creating a space between the first flexural assembly 8 and the second flexural assembly 12 to receive liquid crystal material for the array of the LCD device. Before forming the aforementioned active matrix layer stack and the spacer structure located on the plastic support film, the plastic support film of the second flexural assembly 12 may be loosely and securely attached to the carrier 16. In other words, during the formation of the component on the plastic support film, the carrier 16 can be used to support the plastic support film to generate the second flexural component 12, and the bilateral adhesive unit 14 then functions to resist excessive thermal distortion of the plastic support film during the heating step for forming the component on the plastic support film; and / or restore the plastic support film to its original position on the carrier 16 when the plastic support film is cooled after a heating step.

[0030] In this example, at least one of the first flexural assembly 8 and the second flexural assembly 12 is configured with a thermosetting adhesive for firmly bonding the two flexural assemblies together. The first flexural assembly 8 and the second flexural assembly 12 are then aligned with each other (e.g., a component including alignment marks is part of the second flexural assembly and can be observed from above via the light-transmitting carrier (e.g., glass) 4, the light-transmitting adhesive element 6, and the light-transmitting first flexural assembly 8) and mechanically compressed together between the carriers 4 and 16. Figure 1B). Despite mechanical compression, the assembly (and carriers 4, 16) is uniformly heated in an oven while the adhesive between the first flexure component 8 and the second flexure component 12 of the assembly is fully cured (to establish a zero temperature gradient covering the assembly). Whether the adhesive between the two flexure components is fully cured or not can be determined, for example, by subjecting the assembly to a peel strength test and comparing the measured peel strength with a known or predetermined maximum peel strength for the particular adhesive used. Meanwhile, the presence of uncured adhesive within the assembly between the two flexure components, for example, has a damaging effect on liquid crystal materials; the presence of uncured adhesive (i.e., the inability to fully cure the adhesive) itself contributes to performance degradation of the liquid crystal display device.

[0031] This heating operation may consist of raising the oven temperature in a series of steps and maintaining the oven at each step temperature for an additional period of time. The heating operation required to cure the adhesive includes raising the temperature of the assembly to a temperature at which the plastic support film within the assembly tends to wrinkle, but as discussed below, the pressure mechanically compressing the assembly between the carriers is high enough to substantially prevent any significant wrinkling.

[0032] After sufficient heating has been performed to fully cure the adhesive between the first flexural assembly 8 and the second flexural assembly 12, the temperature of the oven is reduced and the assembly and carrier inside the oven are allowed to cool, while the assembly between the two carriers is continuously compressed to prevent wrinkling of the plastic film during the cooling process. In this example, the adhesive used for the adhesive element 6 (between the first flexural assembly and the rigid carrier 4) and the adhesive used for the second adhesive layer 14a maintain their adhesion to the adhesive strength of the assembly / carrier during the heating process to fully cure the adhesive between the first flexural assembly 8 and the second flexural assembly 12. On the other hand, the thermally released adhesive used for the thermally released adhesive layer 14c is a material that generates gas during the heating process of the assembly to cure the adhesive between the first flexural assembly 8 and the second flexural assembly 12. As explained below, the generated gas forms an air pocket at the interface between the pyrolytic adhesive layer 14c and the rigid carrier 16, and the formation of the air pocket serves to partially reduce the adhesive strength between the pyrolytic adhesive layer 14c and the carrier 16. The pressure compressing the assembly between the carriers 4 and 16 is (i) low enough to maintain the gas generated in the pyrolytic adhesive layer 14c as an air pocket at the interface between the pyrolytic adhesive layer 14c and the carrier 16 (i.e., to prevent the gas generated in the pyrolytic adhesive layer 14c from being laterally discharged between the pyrolytic adhesive layer 14c and the carrier 16), but (ii) high enough to prevent wrinkling (out-of-plane distortion) of the plastic support film within the assembly during the process of heating the assembly to cure the adhesive between the two flexural components.

[0033] The generation of gas within the pyrolytic adhesive layer 14c and the retention of the generated gas at the interface between the pyrolytic adhesive layer 14c and the carrier 16 can be detected by performing the heating operation under a vacuum and monitoring the pressure change within the vacuum chamber; and / or by remote analysis, for example, by spectroscopic methods, at the interface between the pyrolytic adhesive layer 14c and the carrier 16.

[0034] After cooling the assembly to a temperature at which the plastic support film within the assembly no longer tends to wrinkle (during this cooling operation, the air bag is continuously maintained at the interface between the pyrolytic adhesive layer 14c and the rigid carrier 16), the mechanical compression of the assembly between the carriers ends, and the bonding of the assembly to the carriers 4 and 16 is achieved by placing the carrier 16 and the pyrolytic adhesive layer 14c adjacent to the surface of the hot plate on a hot plate, thereby establishing a temperature gradient covering the bonding between the two adhesive units 14 and the assembly. Without mechanical compression of the assembly between the carriers 4 and 16, the hot plate is used to raise the temperature of the pyrolytic adhesive layer 14c to a temperature at which, without mechanical compression, the pyrolytic adhesive layer 14c thermally expands to a range sufficient to further reduce the adhesive strength between the pyrolytic adhesive layer 14c and the rigid carrier 16. This further heating of the thermally released adhesive layer 14c is performed at a temperature that does not increase the temperature of the assembly to a level where the plastic support film within the assembly tends to wrinkle significantly. In one example, the temperature at which the thermally released adhesive layer 14c rises may be higher than the maximum temperature reached during the heating process for curing the adhesive between the first flexure assembly 8 and the second flexure assembly 12. However, the release of the carrier 16 during this second heating phase can also be achieved at a lower temperature. During this second heating phase, the thermal expansion of the adhesive layer 14 reduces the adhesive strength between the adhesive material and the carrier 16 in the contact area surrounding the air bag at the interface between the carrier 16 and the thermally released adhesive layer 14c; and this further reduction in the adhesive strength between the carrier and the thermally released adhesive layer 14c allows the carrier to be released from the assembly without mechanical force or with only a very small force. Figure 1 C).

[0035] Releasing a rigid carrier 16 facilitates the detachment of the entire bilaterally bonded unit 14 from the assembly. Figure 1 D) and the subsequent peeling of the assembly from the adhesive element 6 ( Figure 1 D).

[0036] The liquid crystal material used for the lateral array of the liquid crystal device may be distributed on the second flexure component 12 before the first flexure component 8 and the second flexure component 12 are stacked, or it may be injected into the space created by the spacer structure after the adhesive between the first flexure component 8 and the second flexure component 12 is cured.

[0037] By way of example: In the technology described above, one of the double-sided adhesive units 14 uses an adhesive product obtained from Nitto Denko Corporation with the product name RAU-5HD1.SS; and in the technology described above, another adhesive element 6 uses an adhesive product obtained from Nitta Corporation with the product name CX2325CA3. The adhesive product with the product name RAU-5HD1.SS contains a thermally released adhesive and a UV-release adhesive located on opposite sides of a flexural support film, and the adhesive product with the product name CX2325CA3 contains a cold-release adhesive and a pressure-sensitive adhesive located on opposite sides of a flexural support film.

[0038] In the examples described above, the adhesive strength of the thermally released adhesive layer 14c adjacent to the carrier to an adjacent component is partially reduced by mechanical compression during the heating process used to cure the adhesive between the two carriers, and further reduced (without mechanical compression) after the heating process for curing the adhesive between the two carriers is completed. However, in an alternative example, this layer may be the second adhesive layer 14a adjacent to the assembly in the double-sided adhesive unit 14 (whereby the double-sided adhesive unit 14 is first released from the assembly), or this layer may be a single adhesive layer in contact with both the assembly and the carrier.

[0039] In the example described above, a heat-curable adhesive is used to secure the two flexible components together, but (a) an adhesive that can be cured by exposure to, for example, ultraviolet radiation (UV-curable adhesive), (b) a pressure-sensitive adhesive, or (c) an adhesive that can be cured by laser are other examples of adhesives that can be used to secure the two flexible components together. Even when the two flexible components can be secured together without applying force, heating the assembly to a temperature at which the plastic support film within the assembly tends to wrinkle can be used for other purposes; and the techniques described above are equally useful in such cases.

[0040] In the example described above, the technology is used to manufacture an array of liquid crystal display devices, but the same technology can be used to manufacture other devices, such as, for example, active matrix organic light-emitting diode (OLED) displays for encapsulating the organic light-emitting elements between moisture and oxygen barrier elements.

[0041] The techniques described above can be used to manufacture an assembly in which no significant wrinkling occurs in the plastic support film of any flexural component, even when the flexural component has a relatively large area.

[0042] Apart from any modifications explicitly mentioned above, it will be apparent to those skilled in the art that other different modifications can be made to the specific embodiments described herein while still being covered within the scope of the invention.

Claims

1. A processing method, the processing method comprising: An assembly is provided that is temporarily attached to at least one carrier on opposite sides by means of adhesive elements, the assembly including at least one plastic support sheet; While mechanically compressing the assembly and the adhesive element, the assembly is heated, wherein... During heating of the assembly and the adhesive element under mechanical compression, the adhesive strength of the adhesive element to the carrier and / or the assembly decreases; and wherein, after the pressure of the mechanical compression of the assembly and the adhesive element is partially or completely removed, the adhesive strength of the adhesive element to the carrier and / or the assembly can be further reduced by further heating the adhesive element.

2. The processing method according to claim 1, the processing method further comprising: after partially or completely reducing the pressure of the mechanically compressed assembly and the adhesive element, further heating the adhesive element to further reduce the adhesive strength of the adhesive element to the carrier and / or the assembly, and releasing the adhesive element from the carrier and / or the assembly.

3. The processing method according to claim 1 or 2, wherein, While mechanically compressing the assembly and the adhesive element, reducing the adhesive strength of the adhesive element to the carrier and / or the assembly includes: creating an air pocket at the point where the adhesive element contacts the carrier and / or the assembly, thereby reducing the contact area between the solid material of the adhesive element and the carrier and / or the assembly; and wherein further reducing the adhesive strength between the adhesive element and the carrier and / or the assembly includes: thermally expanding the solid material of the adhesive element to sever the contact between the solid material of the adhesive element and the carrier and / or the assembly at the location between the air pockets.

4. The processing method according to claim 1, wherein the processing method comprises: The carrier and the assembly are detached from the adhesive element without the other carrier and the assembly being detached from the adhesive element.

5. The processing method according to claim 1, wherein, The assembly includes a liquid crystal display component, which includes a spacer and two plastic support sheets. The spacer is used to create a space between the two plastic support sheets to receive liquid crystal material.

6. The processing method according to claim 1, wherein, The assembly includes two plastic support sheets, with corresponding carriers for supporting the respective plastic support sheet during the process of overlapping the two plastic support sheets to form the assembly.

7. The processing method according to claim 1, wherein, The adhesive element includes a support sheet and two adhesive layers supported on opposite sides of the support sheet.

8. The processing method according to claim 1, wherein, The assembly includes a plastic support sheet that supports a stack of conductor layers, semiconductor layers, and insulator layers that define the active matrix array of thin-film transistors.

9. The processing method according to claim 6, further comprising: Releasing one of the carriers from the assembly without releasing the other of the carriers from the assembly, and subsequently stripping the assembly from the other of the carriers.

10. The processing method according to claim 1, wherein, Heating to reduce adhesive strength also includes curing the adhesive contained in the assembly.

11. The processing method according to claim 1, the processing method comprising: after heating and simultaneously mechanically compressing the assembly and the adhesive element, cooling the assembly and simultaneously continuing to mechanically compress the assembly and the adhesive element; wherein during the heating and / or cooling of the assembly and the adhesive element under mechanical compression, the adhesive strength of the adhesive element to the corresponding carrier and / or the assembly is reduced; and wherein after partially or completely removing the pressure of the mechanical compression of the assembly and the adhesive element, the adhesive strength of the adhesive element to the carrier and / or the assembly can be further reduced by further heating the adhesive element.

12. A processing method, the processing method comprising: An assembly is provided that is temporarily attached to a carrier on opposite sides by means of respective adhesive elements, the assembly including at least one plastic support sheet; The assembly is heated to fully cure an adhesive contained within the assembly, wherein the adhesive strength of the adhesive element to the carrier and / or the assembly is reduced during the heating and remains reduced after cooling, and the adhesive strength can be further reduced by further heating after the adhesive contained within the assembly is fully cured and after cooling.

13. A processing method, the processing method comprising: An assembly is provided that is temporarily attached to a carrier on opposite sides by means of at least one adhesive element, the assembly including at least one plastic support sheet, the adhesive element including at least one adhesive layer; The assembly is heated to fully cure an adhesive contained within the assembly, wherein the adhesive layer's adhesion strength to the carrier and / or assembly decreases during heating and remains reduced after cooling. After heating the assembly to fully cure the adhesive contained within it and subsequently cooling the assembly, the adhesive layer expands and is released from the carrier and / or the assembly.

14. The processing method according to claim 13, wherein, Reducing the adhesive strength of the adhesive layer to the carrier and / or assembly includes generating gas within the adhesive layer and maintaining an air pocket at the interface of the adhesive layer.

15. The processing method according to claim 14, wherein, Maintaining an air bag at the interface of the adhesive layer includes: maintaining an air bag at the interface between the adhesive layer and the carrier.

16. The processing method according to claim 13, wherein, The expansion of the adhesive layer further reduces the adhesive strength of the adhesive layer to the carrier and / or assembly.

17. The processing method according to claim 13, wherein, Expanding the adhesive layer includes placing the carrier and assembly on a hot plate, wherein the adhesive layer is located between the hot plate and the assembly.

18. The processing method according to claim 13, wherein, Expanding the adhesive layer includes: establishing a temperature gradient covering the adhesive layer and the assembly, wherein the temperature gradient includes a temperature of the adhesive layer that is higher than the temperature of the assembly.

19. The processing method according to claim 13, wherein, Expanding the adhesive layer includes heating the adhesive layer to a temperature higher than the maximum temperature reached during heating the assembly to fully cure the adhesive contained within the assembly.

20. The processing method according to any one of claims 13-19, wherein, Releasing the adhesive layer from the carrier and / or assembly includes: releasing the adhesive layer from one of the carrier and the assembly, and subsequently peeling the other of the carrier and the assembly from the adhesive element.

21. The processing method according to any one of claims 13-19, wherein, Releasing the adhesive layer from the carrier and / or assembly includes: releasing the adhesive layer from one of the carrier and the assembly without releasing the adhesive layer from the other of the carrier and the assembly.

22. The processing method according to any one of claims 13-19, wherein, The assembly includes a liquid crystal display component, which includes a spacer and two plastic support sheets. The spacer is used to create a space between the two plastic support sheets to receive liquid crystal material.

23. The processing method according to any one of claims 13-19, wherein, The assembly includes two plastic support sheets, with corresponding carriers for supporting the respective plastic support sheet during the process of overlapping the two plastic support sheets to form the assembly.

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