Method for forming a 3D display stack - Patents.com

Abstract

It improves optical coupling between layers of the display stack and avoids visible artifacts or defects in the manufactured 3D display. A method for forming a 3D display stack, the method comprising: providing a first layer 11 comprising a display layer and a touch sensor layer; - attaching 12 a first portion and a second portion of an adhesive layer to the top side of the first layer; - attaching a cover glass to a first portion of the adhesive layer 13; - attaching the 3D faceplate to the second part of the adhesive layer 14; Includes.

Description

[Technical field]

[0001] An example relates to a method for forming a 3D display stack having a cover glass and a 3D faceplate. The method includes using an adhesive layer to attach the 3D faceplate and the cover glass. A further example relates to a 3D display stack including the adhesive layer, the cover glass and the 3D faceplate. [Background technology]

[0002] In modern vehicles, user interaction between the user and vehicle systems (e.g., entertainment systems, driving systems, information systems, etc.) is becoming more and more important as the number of vehicle functions is constantly increasing. For example, in terms of autonomous driving, vehicle users have more and more time to spend on such systems, since they may no longer need to drive the car, at least in certain situations. For example, user interaction systems and output devices (e.g., displays) are becoming more important to the overall user experience.

[0003] Larger display screens may be used to provide the output of the system to the user. For example, analog gauges, dials, and instruments are increasingly being replaced with digital displays. However, typical digital displays are typically flat, 2D surfaces that lack, for example, the perceived value and three-dimensional detail of analog instruments. Current display technology may be limited to two-dimensional (2D) flat surfaces, for example, due to cost constraints or technical constraints. For example, some other concepts provide flexible displays that are bendable only along one axis. Such displays may be limited in terms of the design of the display surface and may be costly.

[0004] Patent Document 1 discloses an optical faceplate for a two-dimensional display. The disclosure relates to an optical faceplate for use in a two-dimensional display. The optical faceplate includes a contact surface on the underside of the optical faceplate for contacting the two-dimensional display. The optical faceplate further includes a three-dimensional (3D) display surface on the upper side of the optical faceplate, and an optical light guide material disposed between the contact surface and the three-dimensional display surface. As a result, a 3D display system can be obtained.

[0005] However, assembling different components of a 3D system can be difficult in some cases, for example depending on the design of the display components. It can be difficult to bring different layers and components into contact in one manufacturing process while maintaining high optical display quality. For example, optical bonding between the display layers and the 3D faceplate does not always meet the highest quality standards. In some cases, air bubbles can get trapped between the layers of such displays, resulting in lower display quality. Visible display defects can cause discomfort to the user and dissatisfaction with the user experience. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] European Patent Application Publication No. 3916442 Summary of the Invention [Problem to be solved by the invention]

[0007] There may be a need for improvements in the manufacturing process of 3D displays that improve optical coupling between layers of the display stack and help avoid visible artifacts or defects in the manufactured 3D displays. [Means for solving the problem]

[0008] Said need is addressed by the subject matter of the independent claims. Further examples of the proposed concept are explained in the dependent claims, in combination with the following description and drawings.

[0009] An embodiment of the present disclosure relates to a method for forming a 3D display stack. The proposed method includes providing a first layer including a display layer and a touch sensor layer, attaching a first portion and a second portion of an adhesive layer (e.g., a film layer or a liquid layer) on top of the first layer, attaching a cover glass to the first portion of the adhesive layer, and attaching a 3D faceplate to the second portion of the adhesive layer.

[0010] A 3D display stack is a display stack having at least one three-dimensional display element. The 3D display stack includes at least one three-dimensional display portion, i.e. at least a 3D faceplate, on top of the 3D display stack. The 3D display stack formed by the proposed method can include two or more separate 3D faceplates that can be attached to a second portion (e.g., including two or more sub-portions) of the adhesive layer. The display layer and the touch sensor layer can be provided separately (out-cell) or in combination (in-cell / on-cell). For example, a 3D touch function can also be provided.

[0011] The different steps of the proposed method can be performed in different orders depending on the manufacturing needs, the materials and techniques used, e.g. adhesive materials. The adhesive layer can be attached to the first layer, for example, before attaching the cover glass and / or 3D faceplate to the adhesive layer. Alternatively, the order can be changed, for example, the cover glass and / or 3D faceplate can be attached to the adhesive layer before attaching it to the first layer containing the display (e.g., using a flip method to bond the cover glass and / or 3D faceplate to the first layer).

[0012] The 3D faceplate can be attached to a larger display and therefore surrounded by a protective layer called a cover glass, which can be any material, not necessarily glass (e.g., it can include or be a suitable polymer or type of plastic material).

[0013] According to one example, the adhesive layer material extends continuously over the first and second portions of the adhesive layer. For example, a single continuous adhesive film can be used. The adhesive film (e.g., an optically transparent adhesive film) including the first and second portions of the adhesive layer can be attached to the first layer in one step. Using the same adhesive layer for the first and second portions of the adhesive layer can reduce the number of method steps and simplify the manufacturing process.

[0014] Alternatively, according to another example, the second part of the adhesive layer is attached separately (e.g., a separate part) from the first part of the adhesive layer. This allows, for example, to use different adhesive layer materials for different parts. For good optical coupling properties, different adhesive materials may be required, for example, for the cover glass and the 3D face plate. It is also possible, for example, to attach the first part of the adhesive layer to the first layer before the cover glass is attached to the first part of the adhesive layer, while attaching the second part of the adhesive layer to the 3D face plate before the second part of the adhesive layer is attached to the first layer. It is also possible to use different adhesive layers for the first and second parts of the adhesive layer, and to attach the first and second parts in a common step, for example simultaneously. This may allow for greater flexibility in the use of adhesive layer materials without extending the manufacturing process in time.

[0015] Thus, for example, an adhesive layer material is used for the first and second parts of the adhesive layer. Both the first and second parts can be formed by, for example, optically clear adhesive (OCA) films (e.g., pieces) having different thicknesses. This can be beneficial if the cover glass and the base of the 3D faceplate have different thicknesses (which can be compensated for by the different film thicknesses of the first and second parts).

[0016] Alternatively, for example, different adhesive layer materials are used for the first and second parts of the adhesive layer. Thus, an optically clear adhesive (OCA), for example an OCA film, can be used for the attachment of the cover glass, and an optically clear resin (OCR) can be used for the attachment of the 3D faceplate. Different adhesive layer materials can be selected to enable optimal optical coupling for different elements of the 3D display stack. For example, when using a first adhesive layer material, the optical coupling between the cover glass and the first layer can be better than when using a second adhesive layer material, while the optical coupling between the 3D faceplate and the first layer can be better when using a second adhesive layer material. For example, as described above, at least one of an optically clear adhesive (OCA) film material, an optically clear resin (OCR) film material, or a liquid optically clear adhesive (LOCA) material is used as the adhesive layer material.

[0017] For example, a liquid optically clear adhesive (LOCA) material is used as the adhesive layer material for the second portion of the adhesive layer. Attaching the 3D faceplate includes pressing the 3D faceplate against the liquid optically clear adhesive material so that the liquid optically clear adhesive material flows into a gap horizontally positioned between the 3D faceplate and the cover glass. A low viscosity OCR can be used to allow the material to flow. As a result, after the process, the gap is filled with the LOCA.

[0018] The LOCA or OCR can be dispensed as droplets or patterns (e.g., depending on the size or shape of the 3D faceplate) to, for example, flow under the 3D faceplate (in the horizontal gap), displace trapped air (if not vacuum), and cover the entire surface of the 3D faceplate. The dispensed amount of LOCA or OCR, the material viscosity, and the amount of pressure applied to the 3D faceplate determine the bond thickness. Insufficient LOCA amount, viscosity, and pressure means that the 3D faceplate will not bond properly (e.g., visible gaps / voids or trapped air), and thus can be avoided in the proposed process. An additional amount of LOCA or pressure can be used to fill vertical gaps (located horizontally between the edge of the 3D faceplate and the cover glass). According to the proposed method, by precisely controlling the conditions (e.g., amount of LOCA and pressure), horizontal and vertical gaps can be filled without or with minimal excess LOCA squeezed out of the joint (excess adhesive needs to be washed or removed). This can help, for example, to minimize manufacturing costs.

[0019] For example, the use of LOCA may require a subsequent step to cure (set, harden, change phase from liquid to solid, etc.) the adhesive, which can be done, for example, at ambient temperature, elevated temperature, UV light, etc. Trapped air or bubbles need to be prevented or removed (e.g., using vacuum or pressure autoclaving).

[0020] Filling the gap in this manner may make it possible to avoid visible artifacts or defects due to open gaps between the 3D faceplate and the coverglass. Horizontal gaps between the 3D faceplate and the coverglass may exist due to manufacturing tolerances and to allow positioning of the 3D faceplate next to the coverglass (e.g., in a notch or opening in the coverglass).

[0021] For example, providing the first layer may include adhering a touch sensor layer to the top side of a display layer using an adhesive layer. Using a touch sensor layer separate from the display layer may allow for greater flexibility in display and touch sensor combinations. Alternative embodiments may utilize a touch sensor layer integrated (e.g., by the display manufacturer) within the display stack, for example to facilitate the manufacturing process.

[0022] For example, the method may further include performing a quality control step after at least one of adhering the touch sensor layer on top of the display layer, attaching the cover glass to a first portion of the adhesive layer, or attaching the 3D faceplate to a second portion of the adhesive layer. Quality control may be required at certain steps or at each step to ensure that the lamination is at an acceptable quality level, e.g., no trapped air bubbles, no defects or foreign objects. Optionally, the quality control step may incorporate machine vision (machine learning or AI aspects) to evaluate the appearance of the display image across the display / touch stack, cover glass, and 3D faceplate. Such an approach may be used to evaluate, grade, reject, etc. the final result at each quality control checkpoint / stage. Learning based on the evaluation may be collected to provide data or highlight areas for improvement in the process.

[0023] For example, the method can further include using a mounting tool to attach the cover glass and / or the 3D faceplate to the adhesive layer. The mounting tool can be adapted to the shape of the 3D faceplate. For example, the cross-sectional shape of the mounting tool is adapted to the cross-sectional shape of the 3D faceplate. For example, the mounting tool can manipulate (e.g., manually, by an automated machine, or by robotics) the 3D faceplate, improve the positioning, registration, or alignment of the 3D faceplate, control the pressure distribution across the 3D faceplate, manipulate the angle of the 3D faceplate during bonding (e.g., to facilitate removal of trapped air), etc.

[0024] A further aspect relates to a 3D display stack. The 3D display stack includes a first layer having a display layer and a touch sensor layer. The display layer and the touch sensor layer can be provided as a common layer or in separate sublayers. The 3D display stack also includes an adhesive layer provided on the top side of the first layer, a cover glass (e.g., a cover glass layer) provided on a first portion of the adhesive layer, and a 3D faceplate provided on a second portion of the adhesive layer.

[0025] The outer boundary of the cover glass may overlap (e.g., be aligned) with the outer boundary of the first layer. For example, the cover glass may include one or more openings for one or more 3D faceplates. The one or more openings are provided above the second portion of the adhesive layer.

[0026] For example, the first portion of the adhesive layer is different from the second portion of the adhesive layer. The difference can be the type of material of the first and second portions and / or the different thickness of the first and second portions of the adhesive layer. For example, the adhesive layer material of the second portion of the adhesive layer is an optically transparent resin. For example, the adhesive layer positioned vertically between the 3D faceplate and the first layer has a thickness of at most 10 μm (or at most 5 μm). A thinner adhesive layer thickness can improve the optical coupling quality of the display stack.

[0027] According to one embodiment, the optically transparent resin is horizontally provided between the cover glass and the 3D face plate. As a result, the gap between the cover glass and the 3D face plate can be avoided, which helps to avoid visible artifacts, for example.The optically transparent resin can also be vertically provided between the 3D face plate and the first layer and / or between the cover glass and the first layer.

[0028] Some examples of apparatus and / or methods will now be described, by way of example only, with reference to the accompanying drawings in which: [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 illustrates a flowchart of a manufacturing process for forming a 3D display stack. [Diagram 2] FIG. 2 illustrates an example of a 3D display stack. [Diagram 3] 1 illustrates an exemplary exploded view of a 3D display stack having a continuous adhesive layer. [Figure 4] 1 is an exemplary exploded view of a 3D display stack having different adhesive layer materials for first and second portions of the adhesive layer. FIG. [Diagram 5] FIG. 13 illustrates an example of the use of a mounting tool to mount a 3D faceplate. [Figure 6] FIG. 13 is a diagram showing an example of providing an optically transparent resin horizontally between a 3D face plate and a cover glass. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Various examples are described in further detail with reference to the accompanying drawings, in which several examples are illustrated, in which the thickness of lines, layers and / or regions may be exaggerated for clarity.

[0031] Thus, while the further examples are susceptible to various modifications and alternative forms, some specific examples thereof are shown in the figures and will be described in detail below. However, the detailed description is not intended to limit the further examples to the specific forms described. The further examples may cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure. The same or similar numbers refer to the same or similar elements throughout the description of the figures, which may be implemented in the same or modified form when compared to one another while providing the same or similar functionality.

[0032] When an element is said to be "connected" or "coupled" to another element, it is understood that the elements may be directly connected or coupled via one or more intervening elements. When two elements A and B are combined using "or", this should be understood as all possible combinations, i.e. A only, B only, and A and B, unless otherwise specified, either explicitly or implicitly. Alternative expressions for the same combination are "at least one of A and B" or "A and / or B". The same applies, mutatis mutandis, to combinations of more than two elements.

[0033] Terms used herein for the purpose of describing particular examples are not intended to limit further examples. Where singular forms such as "a," "an," and "the" are used and are not explicitly or implicitly required to use only a single element, further examples may use multiple elements to perform the same function. Similarly, where a function is subsequently described as being performed using multiple elements, further examples may perform the same function using a single element or processing entity. It is also understood that the use of the terms "comprise," "comprising," "includes," and / or "including" specifies the presence of stated features, integers, steps, operations, processes, acts, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, processes, acts, elements, components, and / or groups thereof.

[0034] Unless otherwise defined, all terms (including technical and scientific terms) are used herein in the ordinary sense of the art to which the examples pertain.

[0035] A flow chart of a manufacturing process for forming a 3D display stack is shown in Figure 1. The illustrated method 10 includes providing 11 a first layer including a display layer and a touch sensor layer. The method 10 further includes attaching 12 a first portion and a second portion of an adhesive layer to an upper side of the first layer, attaching 13 a cover glass to the first portion of the adhesive layer, and attaching 14 a 3D faceplate to the second portion of the adhesive layer.

[0036] All steps can be performed in the order described above or in a different order if more appropriate, for example, to achieve a high quality product. For example, in some cases it may be beneficial to attach an adhesive layer to the cover glass and / or 3D faceplate before attaching the adhesive layer to the top side of the first layer, for example to achieve better optical coupling of the display stack.

[0037] Further details and aspects of the concept are described in relation to the proposed concept or one or more examples described above or below (e.g., Figures 2-6). The concept may include one or more additional optional features corresponding to one or more aspects of the proposed concept or one or more examples described above or below.

[0038] An example of a 3D display stack 20 is shown in Figure 2. The 3D display stack 20 includes a first layer 21 having a display layer and a touch sensor layer (shown as a common layer in Figure 2). The 3D display stack 20 further includes an adhesive layer 22 disposed on the top side of the first layer 21, a cover glass 23 disposed on a first portion of the adhesive layer 22, and a 3D faceplate 24 disposed on a second portion of the adhesive layer 22.

[0039] The 3D display stack 20 can be applied, for example, in a vehicle as a central display, a combination / instrument cluster, and / or a rear seat display, and the 3D display stack can be used in a remote control, for example a steering wheel controller or a remote control in a door panel or a center armrest.

[0040] Further details and aspects of the concept are described in relation to the proposed concept or one or more examples (e.g., Figures 1 and 3-6) described above or below. The concept may include one or more additional optional features corresponding to one or more aspects of the proposed concept or one or more examples described above or below.

[0041] In FIG. 3, an exemplary exploded view of a 3D display stack 30 with a continuous adhesive layer 22 is shown. The continuous adhesive layer 22 can be a single adhesive film of a single adhesive material. A first layer 31 is shown, which includes a display layer. A touch sensor film 32 is adhered to the first layer 31 by an optically clear adhesive (OCA) layer 33. On the upper side of the touch sensor film 32, a continuous adhesive layer 22 is provided for laminating the cover glass 23 and the 3D faceplate 24 to the display stack (e.g., in a composite lamination process). The continuous adhesive layer 22 can be composed of one continuous adhesive film, e.g., with a simplified manufacturing process. Alternatively, the continuous adhesive layer can include the same adhesive material (e.g., continuous material properties) and can include multiple adhesive film pieces, e.g., improving manufacturing flexibility and providing the possibility for different thicknesses of a single adhesive film piece.

[0042] In this example, an approach is shown for an out-cell touch sensor, where the touch sensor is externally bonded to a display module or display layer. The proposed approach also applies to other configurations, such as on-cell and in-cell (on-cell and in-cell configurations can be based on today's display technology, and variations or alternatives may arise due to future technological advances: for example, in-cell may be more important for OLED displays or MicroLED (μLED, microLED).). In the out-cell type, the touch sensor is on top of the display cell (or display module), suitable for LCD and OLED, for example, and is the most flexible production approach. In the on-cell type, the touch sensor is placed directly on the display cell, for example, under the display polarizer layer, suitable for LCD and OLED displays, for example, for LCD displays, the touch layer may be above or below the LCD cell, and for OLED displays, the touch layer may be above the display cell. In the in-cell type, the touch sensor is placed within the display cell layer, allowing for a highly integrated design for mass production, for example.

[0043] For example, to form a 3D display stack 30, the OCA layers 22, 23 can be attached to the touch sensor film 32 in a first step. In a subsequent step, the first layer 31 can be attached to the underside of the lower OCA layer 33. This can be followed by a cover glass lamination process and a 3D faceplate lamination process. Quality control steps can be performed during some or all of these manufacturing steps. An optional display calibration step can be performed to finalize the process. The lamination step for attaching the OCA layers can optionally include high pressure steam sterilization (autoclaving). The lamination technique used in the process can be roller lamination, screen lamination, drum transfer lamination, arc head lamination, glass bending lamination or roll-to-sheet lamination.

[0044] Further details and aspects of the concept are described in relation to the proposed concept or one or more examples described above or below (e.g., Figures 1-2 and 4-6). The concept may include one or more additional optional features corresponding to one or more aspects of the proposed concept or one or more examples described above or below.

[0045] In FIG. 4, an exemplary exploded view of a 3D display stack 40 with different adhesive materials is shown. As in FIG. 3, an out-cell type touch sensor is shown. In contrast to the example of FIG. 3, the adhesive layer portion for attaching the cover glass 23 is separated from the adhesive layer portion for attaching the 3D faceplate 24. The first portion 22a of the adhesive layer 22 provided for the cover glass 23 may be an optically transparent adhesive. The second portion 22b of the adhesive layer 22 provided for the 3D faceplate 24 may be an optically transparent resin (liquid-based; e.g., liquid optically transparent adhesive). This allows for improved optical properties according to different requirements of the cover glass 23 and the 3D faceplate 24, which for example comprise different materials themselves.

[0046] Further details and aspects of the concept are described in relation to the proposed concept or one or more examples (e.g., Figures 1-3 and 5-6) described above or below. The concept may include one or more additional optional features corresponding to one or more aspects of the proposed concept or one or more examples described above or below.

[0047] In FIG. 5, an example of the use of a fixture or mounting tool 51 for mounting the 3D faceplate 24 is shown. The mounting tool 51 is positioned in the area of ​​the 3D faceplate 24. The fixture 51 applies pressure and / or positions the 3D faceplate at the location of the coverglass (e.g., at the opening of the coverglass 23). The fixture may, for example, provide a means for manipulating (manually, by an automated machine, by a robot, etc.), positioning, orienting or adjusting the position of the 3D faceplate, ensure control of the pressure (e.g., clamping force) applied across the 3D faceplate, protect the 3D faceplate during the process, assist in the manipulation of the 3D faceplate during the bonding process (e.g., application angle and means for releasing trapped air), etc. For example, vacuum lamination (reduced pressure lamination) and / or flip lamination techniques (see also FIG. 6) may be used.

[0048] Further details and aspects of the concept are described in relation to the proposed concept or one or more examples described above or below, such as in Figures 1-4 and 6. The concept may include one or more additional optional features corresponding to one or more aspects of the proposed concept or one or more examples described above or below.

[0049] FIG. 6 shows an example 60 of horizontally providing an optically transparent resin OCR between the 3D faceplate and the cover glass. The optically transparent resin (or LOCA) fills the gap 61 between the 3D faceplate 24 and the cover glass 23, for example due to the tolerance of the opening in the cover glass 23. The OCR in the filled gap can be used for the second part 22b of the adhesive layer 22 for attaching the 3D faceplate 24. For example, a liquid OCR (for example, LOCR) is used for the second part 22b. In the manufacturing process of bonding the 3D faceplate 24, the adhesive material can flow until it fills the gap 61 around the 3D faceplate 24 (for example, when an appropriate amount of OCR, for example, low-viscosity OCR, is provided and pressure is applied to the 3D faceplate 24 when attaching the 3D faceplate 24). The gap 61 can be filled in a second process (for example, after the 3D faceplate is bonded and the trapped air is released), and the gap can be filled. Alternatively, the gap can be filled and glued with a trim piece (e.g., opaque plastic or metal) or mechanically held in place. Thus, the adhesive material filling the gap 61 allows for a flat (flush) connection of the cover glass 23 and the 3D faceplate 24, leading to improved visual and tactile properties of the 3D display stack.

[0050] The OCR layer (i.e., the second portion 22b of the adhesive layer 22) may have a thickness of, for example, less than 5 μm. A primary objective of the present disclosure is to optimize the optical coupling of the 3D faceplate 24 to the display by minimizing the stack-up (e.g., thickness) of the adhesive layer between the 3D faceplate 24 and the display. By using OCR, thinner adhesive layers, for example, about 5 μm, are possible. The cover glass 23 layer may have a thickness of about 1.1 mm (e.g., less than 2 mm), and the OCA layer (e.g., the first portion 22a of the adhesive layer and the lower OCA of the layer 33) may have a thickness of less than 50 μm (e.g., less than 30 μm and / or more than 10 μm). Thus, by using an OCR material for the second portion 22b of the adhesive layer 22 for adhesion of the 3D faceplate, a very thin layer thickness may be possible.

[0051] The OCR material of the second part 22b of the adhesive layer for bonding the 3D faceplate 24 can be applied to the back (e.g., underside) of the touchscreen film 32 or the 3D faceplate 24. The flip method (or face-down method) performs bonding by pressing the stage while maintaining a parallel state under negative pressure or atmospheric pressure; the OCR can be coated on the cover glass by a dispenser; the coated cover glass is rotated 180°, the lower stage is raised, and the OCR is pressed radially to be bonded. The flip method is very suitable for attaching the 3D faceplate 24 because the 3D faceplate 24 is a rigid body, and the use of vacuum lamination can enhance the removal of air bubbles.

[0052] For example, the lamination step of the cover glass 23 attachment can use an OCA film for the first portion 22a of the adhesive layer, while the 3D faceplate 24 can be bonded using OCR or LOCR, so that the 3D faceplate 24 can be bonded separately from the cover glass 23 lamination process.

[0053] Using separate portions 22a, 22b of the adhesive layer 22 to laminate the cover glass layer 23 and the 3D faceplate 24 allows for different thicknesses of the layer portions to be used. For example, the difference in thickness of the layer portions 22a, 22b can be used to compensate for different thicknesses of the cover glass layer 23 and the base 62 of the 3D faceplate 24.

[0054] Further details and aspects of the concept are described in relation to the proposed concept or one or more examples (e.g., Figures 1-5) described above or below. The concept may include one or more additional optional features corresponding to one or more aspects of the proposed concept or one or more examples described above or below.

[0055] Each example is for a 3D faceplate manufacturing process. Such 3D displays enable new forms of user interaction when combined with larger 2D (or some curvature) touchscreen displays (e.g. CID / combination displays, panoramic displays (P2P / pillar-to-pillar)), and there are unique user gestures possible for the 3D faceplate and surrounding 2D displays. 3D display stacks can be used, for example, in vehicles, general transportation, or consumer electronics (e.g. smart devices, laptops, etc.).

[0056] To apply the 3D faceplate 24 to a display or a display having a touch sensor (e.g., capacitive), for example, optical coupling is required to transfer the display image (i.e., light) from the display to and through the 3D faceplate 24. Attaching the faceplate with an optically clear adhesive provides a good solution to the optical coupling requirement (e.g., thin interface layer, optical index matching, etc.). However, the attachment of the 3D faceplate 24 to the display layer and / or touch sensor layer requires optimal manufacturing processes, specific steps and adhesive layer configurations. This is due to the three-dimensional nature of the 3D faceplate, for example, it has an inherently three-dimensional shape, does not match the thickness of the perimeter of the cover glass 23 (e.g., protrudes or extends beyond and / or below, e.g., is of a general shape, such as convex or concave), is a rigid body made of glass or polymer, and is of a different material than the adjacent materials in the display / sensor stack, etc.

[0057] The assembly of 3D faceplates (e.g. by adhesive bonding with OCA (optically clear adhesive), OCR (optically clear resin) or LOCA (liquid optically clear adhesive)) requires different or modified processes than those conventionally used in display or touchscreen manufacturing processes. The configuration of the adhesive layers in the stack may also be different. Different examples are provided: - Continuous OCA layer (bonding cover glass 23 and faceplate 24): A single sheet / film of OCA (e.g. continuous adhesive layer 22) is applied to the top layer (e.g. touch sensor or display (if not touch sensor)) - cover glass and 3D faceplate are bonded / laminated simultaneously or sequentially. The manufacturing process requires that the cover glass 23 is laminated as the last step (in traditional display lamination, the cover glass is often laminated first). - Separate OCA film: Separate or multiple pieces of OCA film (e.g. for the first and second parts 22a and 22b of the adhesive layer) are applied to each of the cover glass 23 and the 3D faceplate 24. For example, the OCA pieces are cut to the shape of the cover glass and the 3D faceplate, aligned to the cover glass and the 3D faceplate, applied to the display / sensor (or aligned directly to the cover glass and the 3D faceplate), and then laminated (e.g. using a vacuum laminator). -Gluing the 3D faceplate 24 by OCR: The 3D faceplate 24 is glued in a separate step, either before or after the cover glass is laminated. In the above-mentioned approaches, tooling may be required to position or hold the 3D faceplate during stacking (e.g. the tooling, e.g. mounting or fixture tool 51, may include details such as alignment features to correctly orient the 3D faceplate, employ vacuum maintenance to pick up and hold the 3D faceplate, etc.).

[0058] These examples relate to quality control steps in the manufacturing process: these may be necessary at each step to ensure that the lamination is at an acceptable quality level, e.g., no trapped air bubbles, no defects or foreign objects. Additionally, quality control steps can incorporate machine vision (machine learning or AI aspects) to evaluate the appearance of the display image across the display / touch stack, cover glass and 3D faceplate. Such approaches can be used to evaluate, grade, reject, etc. the final result at each quality control checkpoint / stage. Gains from the evaluation can be collected to provide data or to highlight areas for improvement in the process (e.g., adhesive application, adhesive pattern (e.g., in the case of liquid adhesives), layer orientation, etc.) - Calibration: As a final step, the entire assembly can be calibrated (e.g., color, brightness, contrast, focus, etc.) and the output of the display in the area of ​​the 3D faceplate (i.e., in the area of ​​the cover glass or in the area outside the 3D faceplate) is adapted to the overall output of the display. One example relates to a method that includes providing a first layer including a display layer and a touch sensor layer, attaching a portion of an adhesive layer (e.g., a film layer or a liquid layer) to an upper side of the first layer, and attaching a 3D faceplate to the portion of the adhesive layer.

[0059] The aspects and features mentioned and described in connection with one or more of the detailed examples and figures above may be combined with one or more other examples to replace similar features of the other examples or to introduce additional features to the other examples.

[0060] The specification and drawings merely illustrate the principles of the present disclosure. Moreover, all examples recited herein are expressly intended for illustrative purposes only to aid the reader in understanding the principles of the present disclosure and concepts contributed by the inventors to the development of the art. All descriptions recited herein of the principles, aspects, and examples of the present disclosure and specific examples thereof are intended to encompass equivalents thereof.

[0061] Block diagrams may, for example, illustrate high level circuit diagrams implementing the principles of the present disclosure. Similarly, flowcharts, flow diagrams, state diagrams, pseudo code, and the like may represent various processes, operations, or steps that may, for example, be substantially represented in a computer-readable medium and thus executed by a computer or processor, whether or not such a computer or processor is explicitly shown. The methods set forth in the specification or claims may be performed by an apparatus having means for performing each of the operations of the method.

[0062] It should be understood that the disclosure of multiple operations, processes, operations, steps, or functions disclosed in the specification or claims may not be construed as being in a particular order unless expressly or implicitly stated otherwise, for example, for technical reasons. Thus, the disclosure of multiple operations or functions does not limit the operations or functions to a particular order, unless such operations or functions are not interchangeable for technical reasons. Furthermore, in some instances, a single operation, function, process, operation, or step may include or be divided into multiple sub-operations, sub-functions, sub-processes, sub-operations, or sub-steps, respectively. Such sub-operations may be included in the disclosure of the single operation and may be part of the disclosure, unless expressly excluded.

Claims

1. A method (10) for forming a 3D display stack (20), the method comprising: - providing a first layer (21) (11) comprising a display layer and a touch sensor layer; - attaching (12) a first part and a second part of an adhesive layer (22) on top of said first layer (21); - attaching (13) a cover glass (23) to said first part of said adhesive layer (22); - attaching (14) a 3D faceplate (24) to said second part of said adhesive layer (22); A method (10) comprising:

2. 2. The method (10) of claim 1, wherein glue line material extends continuously across the first and second portions of the glue line (22).

3. 2. The method (10) of claim 1, wherein the second portion of the adhesive layer (22) is attached separately from the first portion of the adhesive layer (22).

4. 4. The method (10) of claim 3, wherein the same adhesive layer material is used for the first and second portions of the adhesive layer (22).

5. 4. The method (10) of claim 3, wherein different adhesive layer materials are used for the first and second portions of the adhesive layer (22).

6. The method (10) according to any one of claims 2 to 5, characterized in that at least one of an optically transparent adhesive film material, an optically transparent resin film material or a liquid optically transparent adhesive material is used as the adhesive layer material.

7. 6. The method (10) according to any one of claims 2 to 5, characterized in that a liquid optically transparent adhesive material is used as an adhesive layer material for the second portion of the adhesive layer (22), and attaching (14) the 3D faceplate (24) comprises pressing the 3D faceplate (24) against the liquid optically transparent adhesive material so that the liquid optically transparent adhesive material flows into a gap (61) horizontally positioned between the 3D faceplate (24) and the cover glass (23).

8. 6. The method (10) of any one of claims 1 to 5, wherein providing (11) the first layer comprises adhering a touch sensor layer (32) on top of the display layer using an adhesive layer (33).

9. 6. The method (10) of any one of claims 1 to 5, further comprising performing a quality control step after at least one of adhering the touch sensor layer on top of the display layer, attaching the cover glass (13) to the first portion of the adhesive layer, or attaching the 3D faceplate (24) to the second portion of the adhesive layer (22).

10. The method (10) according to any one of claims 1 to 5, further comprising using an attachment tool (51) for attaching (13, 14) the cover glass (23) and / or the 3D faceplate (24) to the adhesive layer (22).

11. A 3D display stack (20) comprising: a first layer (21) having a display layer and a touch sensor layer; an adhesive layer (22) provided on the upper side of the first layer (21); a cover glass (23) provided on a first portion of the adhesive layer (22); and a 3D faceplate (24) provided on a second portion of the adhesive layer (22).

12. 12. The 3D display stack (20) of claim 11, wherein the first portion (22a) of the adhesive layer (22) is different from the second portion (22b) of the adhesive layer (22).

13. 13. The 3D display stack according to claim 11 or 12, wherein the adhesive layer material of the second portion (22b) of the adhesive layer (22) is an optically transparent resin.

14. 14. The 3D display stack of claim 13, wherein the adhesive layer (22) positioned vertically between the 3D faceplate (24) and the first layer (21) has a thickness of at most 15 μm.

15. 13. The 3D display stack according to claim 11 or 12, wherein an optically transparent resin is horizontally disposed between the cover glass (23) and the 3D faceplate (24).

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