Patent Publication Number: US-2023142970-A1

Title: Method for producing a polarizer film assembly with a continuous film layer

Description:
BACKGROUND 
     Field of the Disclosure 
     This disclosure relates generally to portable information handling systems and, more particularly, to methods of producing polarizer film assemblies and continuous polarizer film layers. 
     Description of the Related Art 
     As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems. 
     Portable information handling systems such as notebooks are used frequently for teleconferencing and other video communication. These portable information handling systems typically have a hinge-up display assembly to display information to a user (such as a video display displaying video of a person using another information handling system) and a camera to capture video of the user for sending to the other information handling system. The camera is typically deployed at the top center of a hinge-up/display assembly to capture video of the user positioned in front of the portable information handling system. 
     Typically, the camera is located above the LCD panel and behind a cosmetic bezel (non-touch system) or a protective cover glass (touch systems). 
     SUMMARY 
     Embodiments disclosed herein may be generally directed to portable information handling systems and particularly to portable information handling systems with display assemblies with integrated optical sensors. 
     Embodiments disclosed herein may be directed to a method for producing a polarizer film assembly for a display assembly of an information handling system, wherein the display assembly may include a camera or other I/O component with functionality that is negatively affected by a polarizer film. 
     Embodiments of a method of manufacturing a polarizer film assembly for a display assembly having a display assembly width and a display assembly height comprise forming a mask on a base film substrate to form a set of masked areas and a set of unmasked areas, wherein at least one masked area corresponds to a position of an optical sensor in the display assembly. The method further comprises creating a set of optical targets on the base film substrate and applying a dye to the base film substrate to form a polarizer film on the set of unmasked areas, wherein the set of masked areas prevent the dye from adhering to the base film substrate. The method further comprises aligning the base film substrate relative to a cutter based on the set of optical targets and cutting the base film substrate relative to the set of optical targets to form a continuous polarizer film assembly with a polarizer film assembly width substantially equal to the display assembly width and a polarizer film assembly height substantially equal to the display assembly height. 
     In some embodiments, forming a mask on a base film substrate comprises depositing a material on the base film substrate prior to prior to applying the dye to the base film substrate to prevent the dye from adhering to the base film substrate. In some embodiments, forming a mask on a base film substrate comprises forming a continuous strip that runs the full length of the roll of base film substrate. The strip may form a top border of the polarizer layer. Forming the strip may include printing or depositing a material on the roll of base film substrate as the roll of base film substrate is unrolled. 
     In some embodiments, forming a mask on a base film substrate by depositing a material comprises printing on the base film substrate prior to applying the dye to the base film substrate to prevent the dye from adhering to the base film substrate. In some embodiments, the method comprises removing the mask after applying the dye. 
     In some embodiments, forming a mask on a base film substrate comprises modifying the base film substrate to prevent the dye from adhering to the base film substrate. In some embodiments, modifying the base film substrate comprises polishing the base film substrate to form the set of masked areas. In some embodiments, modifying the base film substrate comprises etching the base film substrate to form the set of masked areas. In some embodiments, modifying the base film substrate comprises etching or polishing a continuous strip that runs the full length of the roll of base film substrate. 
     In some embodiments, creating a set of optical targets on the base film substrate comprises creating a set of borders such that, after stretching and other processing steps, the borders correspond to the display assembly width and the display assembly height and cutting the base film substrate relative to the set of optical targets comprises cutting along the set of borders. 
     In some embodiments, creating a set of optical targets on the base film substrate comprises creating a set of fiducials inside or outside the set of borders, wherein aligning the base film substrate relative to a cutter based on the set of optical targets comprises aligning the base film substrate based on the set of fiducials. 
     In some embodiments, a continuous strip of material formed by depositing a material or modifying the base film substrate may be used as an optical target in the set of optical targets. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the invention and its features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    is a perspective exploded view of a display assembly for an information handling system having a camera or other optical sensor; 
         FIG.  2    is a top view of a sheet of base film substrate configured with a set of areas for polarizing, a set of areas for not polarizing, and a set of optical targets for ensuring a polarizer film assembly formed from the base film substrate has non-polarized areas positioned relative to an optical sensor, according to one embodiment; 
         FIG.  3    is a flow diagram of a method for manufacturing one embodiment of a polarizer film assembly for assembly in a display assembly for an information handling system having a camera; 
         FIG.  4    is a top view of a base film substrate in which all areas are polarized; and 
         FIG.  5    is a flow diagram of a common approach for manufacturing a polarizer film assembly for use in a display assembly for an information handling system. 
     
    
    
     DESCRIPTION OF PARTICULAR EMBODIMENT(S) 
     In the following description, details are set forth by way of example to facilitate discussion of the disclosed subject matter. It should be apparent to a person of ordinary skill in the field, however, that the disclosed embodiments are exemplary and not exhaustive of all possible embodiments. 
     For the purposes of this disclosure, an information handling system may include an instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize various forms of information, intelligence, or data for business, scientific, control, entertainment, or other purposes. For example, an information handling system may be a personal computer, a consumer electronic device, a network storage device, or another suitable device and may vary in size, shape, performance, functionality, and price. The information handling system may include memory, one or more processing resources such as a central processing unit (CPU) or hardware or software control logic. Additional components of the information handling system may include one or more storage devices, one or more communications ports for communicating with external devices as well as various input and output (I/O) devices, such as a keyboard, a mouse, and one or more video displays. The information handling system may also include one or more buses operable to transmit communication between the various hardware components. 
     Particular embodiments are best understood by reference to  FIGS.  1 - 5   , wherein like numbers are used to indicate like and corresponding parts. 
       FIG.  1    depicts an exploded perspective view of display assembly  100  comprising multiple layers including backlight panel  12 , rear polarizer film assembly  14 - 1 , LCD cell layer  16  and front polarizer film assembly  14 - 2 . In some information handling systems, display assembly  100  may include bezel  20 , discussed in more detail below. 
     Backlight panel  12  may comprise circuits and electronic components configured for backlighting images displayed on display assembly  100 . As depicted in  FIG.  1   , optical sensor  22  may form part of backlight panel  12 . In some embodiments, circuits in backlight panel  12  may also control the display of images and text in liquid crystal display (LCD) panel  16 . 
     Liquid Crystal Display (LCD) layer  16  comprises circuits and electronic components configured for displaying images and text in black and white and color. 
     Polarizer films are often necessary for the proper function of LCD layer  16 . Front and rear polarizer film assemblies  14 - 1 ,  14 - 2 , each comprising a polarizer film formed on a base film substrate, work in conjunction with the electronically controlled liquid crystal array in LCD layer  16  and backlight panel  12  to display text and images in black and white and color on display assembly  100 . 
     Polarizer Films Negatively Affect Performance of Cameras 
     Polarizer films may improve the display of text and images on display assembly  100 . However, polarizer films typically have a transmissivity of approximately 40% in the visible spectrum, which causes significant difficulties for an information handling system to capture quality images from optical sensor  22 , especially in low light conditions. The negative effects may include darkening of colors or oversaturation of colors and blurring of text, for example. The negative effects generally cannot be corrected by processing algorithms. 
     Non-Touch Display Assemblies 
     Some information handling systems comprise display assemblies  100  without touch screen functionality (i.e., non-touch displays). In some of these information handling systems, front layer  20  comprises a bezel that extends to the height of display assembly  100  but polarizer film assemblies  14  extend to a height less than the height of optical sensor  22  such that the functionality of optical sensor  22  is unaffected by the polarizer film assembly  14 , wherein front layer  20  provides a continuous surface for display assembly  100 . 
     Touch Display Assemblies 
     With the emergence of display assemblies  110  with touchscreen functionality (i.e., touch displays or touchscreens), some information handling systems  100  are manufactured with front layer  20  comprising a protective cover glass as a continuous layer over the entire height and width of display assembly  100 . In some of these information handling systems, front layer  20  may extend to the height of display assembly  100  but polarizer film assembly  14  extends to a height less than the height of optical sensor  22  such that the functionality of optical sensor  22  is unaffected by the polarizer film assembly  14 , wherein front layer  20  provides a continuous surface for display assembly  100  and protects touch screen components. 
     A bezel and a cover glass may protect other layers and touchscreen components in display assembly  100  but add weight and cost. In some information handling systems, front layer  20  may not be present. In some of these information handling systems, polarizer film assemblies  14  may extend to a height less than the height of optical sensor  22  such that the functionality of optical sensor  22  is unaffected by the polarizer film assembly  14 . However, a user may feel a discontinuous surface of display assembly  100 . 
     Edge-to-Edge Displays 
     With a push to produce portable information handling systems with edge-to-edge display areas, there is no bezel  20  and display assemblies  100  with cameras  22  or other optical sensors must include polarizer film assemblies  14  that do not affect the capability of optical sensor  22  to capture images or other optical information. A front polarizer film assembly  14 - 1  may extend the full height and width of the display assembly  100  and would need a non-polarizer area in front of a camera, but a rear polarizer film assembly  14 - 2  that does not extend the full height of the display assembly would not need a non-polarizer area. 
     Embodiments disclosed herein may include a polarizer film assembly  14  for use in a display assembly  100 , wherein the polarizer film assembly  14  comprises a base film substrate that may be generally covered by a polarizer film but with a set of non-polarized areas corresponding to the position of optical sensors  22  that may be affected by polarizer films. 
     Referring to  FIGS.  2  and  3   ,  FIG.  2    depicts a base film substrate  200  configured with a set of optical targets for forming a polarizer film assembly  14  and  FIG.  3    depicts a flow diagram of a method for manufacturing one embodiment of a polarizer film assembly  14  for use in a display assembly  100  for an information handling system. The display assembly  10  may have a camera or other optical sensor  22  that is negatively affected by a polarizer film. A camera could be a color (RGB) sensor/camera or an infrared (IR) sensor/camera, for example. 
     Base film substrate  200  may be, for example, polyvinyl alcohol (PVA) supplied in a continuous roll of material. 
     At step  302 , a mask is formed on base film substrate  200  to form a set of unmasked areas  204  and a set of masked areas  210 . 
     In some embodiments, a mask may be formed by material deposition onto base film substrate  200 , wherein the material deposited on base film substrate  200  has properties that prevent a polarizer film from adhering to base film substrate  200 . For example, in some embodiments, a mask may be formed by printing a layer of material onto base film substrate  200 , wherein the printed material has surface properties that prevent a dye or other polarizer film to adhere to base film substrate. In some embodiments (not shown), as base film substrate  200  is unrolling, a material is deposited in a continuous strip. The strip may form a top border of a polarizing layer and may be wide to accommodate cutting tolerances in a polarizing layer. 
     In some embodiments, a mask may be formed by modifying base film substrate  200 . For example, in some embodiments, a mask may be formed by polishing the surface of base film substrate  200  to have surface properties that prevent a polarizer film from adhering to base film substrate  200 . 
     The shape of each masked area  210  may be based on ensuring a non-polarized area on a polarizer film assembly  14  aligns with a corresponding component in display assembly  100 . For example, optical sensor  22  may benefit from a circular non-polarized area with a 5 mm diameter, but mechanical processing steps may stretch base film substrate  200 . Accordingly, a masked area  210  corresponding to optical sensor  22  may be formed on base film substrate  200  as a non-circular masked area  210  and have a major diameter less than 5 mm to account for stretching and other changes to base film substrate  200 . 
     At step  304 , a set of optical targets may be formed on base film substrate  200  for correct alignment of base film substrate  200  relative to borders  202  and  206  for cutting base film substrate into polarizer film assemblies  14  in later manufacturing steps, discussed in greater detail below. In some embodiments, an optical target may be a masked area  210  located within borders  202 ,  206 . In some embodiments, an optical target may be a fiducial  208  located outside borders  202 ,  206 . In some embodiments, an optical target may be borders  202 ,  206 . Borders  202 ,  206  may be lines printed on base film substrate  200  or may be defined by edges of unmasked areas  204 . In some embodiments, one or more optical targets may be formed similar to masked areas  210  prevent the dye from adhering to base film substrate  200 . 
     At step  306 , a dye or other material used to form a polarizer film is applied to base film substrate  200 . The dye may adhere to base film substrate  200  in a set of unmasked areas  204 , but the mask prevents the dye from adhering to base film substrate  200  in the set of masked areas  210 . 
     The process  300  to form polarizer film assembly  14  may include inspecting base film substrate  200  to verify the dye adhered to unmasked areas  204  and did not adhere to base film substrate  200  in the set of masked areas  210 . 
     The process to form polarizer film assembly  14  includes other steps. For example, at step  308 , base film substrate  200  may be stretched to align polarizer film in a desired direction. At step  310 , base film substrate  200  may be placed in an oven for drying. Drying may ensure polarizer film stays adhered to base film substrate  200 . 
     In some embodiments, material used to form a mask on base film substrate  200  may be removed. Mechanical and chemical processes needed to remove the mask may differ from mechanical and chemical processes needed to remove polarizer film deposited on unmasked areas  204 , whereby removal of the mask may be less aggressive and use fewer resources and less time than removing polarizer film later. 
     At step  312 , base film substrate  200  with a set of polarized areas and a set of non-polarized areas may be laminated with layers of tri-acetyl cellulose (TAC) or other material to protect the polarizer film. At step  314 , a phase difference film (PF) may be applied to base film substrate  200 . Other chemicals may be applied and other mechanical processes may occur to complete the manufacture of polarizer film assembly  14 . 
     At step  316 , base film substrate  200  may be cut into individual polarizer film assemblies  14 , with each polarizer film assembly  14  being configured for assembly into display panel  100  such that a non-polarized area of polarizer film assembly  14  is positioned relative to an optical sensor  22 . Cutting may include aligning base film substrate  200  to a cutter using the set of optical targets. The set of optical targets may include fiducials  208 , non-polarized areas corresponding to masked areas  210  or borders  202 ,  206  of unmasked areas  204 . In some embodiments, base film substrate  200  may have a continuous strip (not shown) formed along its length and the continuous strip may be used as an optical target for alignment. Aligning ensures cutting is along borders  202  and  206  relative to unmasked areas  204 . 
     Once cut, each polarizer film assembly  14  has a polarizer film assembly width substantially equal to the display assembly width and a polarizer film assembly height substantially equal to the display assembly height, and at least one non-polarized area corresponding to a masked area  210  is positioned relative to an optical sensor  22 . 
     Polarizer film assembly  14  be positioned relative to other layers in display assembly  100  to ensure display assembly  100  displays clear images and text in black and white or color and ensure optical sensor  22  is able to capture clear images and text in black and white or color. In some embodiments, backlight panel  12  may be assembled after polarizer film assembly  14  is assembled and after a printed circuit board assembly (PCBA) is assembled. 
     Embodiments described herein overcome several shortcomings of traditional approaches to manufacturing display assemblies. 
     Referring to  FIGS.  4  and  5   ,  FIG.  4    depicts a top view of base film substrate  200  without any markings, and  FIG.  5    depicts a flow diagram of a common approach to manufacturing a polarizer film assembly. 
     As depicted in  FIG.  5   , at step  306 , a dye or other polarizer film or film is applied to base film substrate  200 . The dye may adhere to base film substrate  200  over the entire surface of base film substrate. 
     A traditional approach to form polarizer film assembly  14  includes other steps. For example, at step  308 , base film substrate  200  may be stretched to align polarizer film in a desired direction. At step  310 , base film substrate  200  may be placed in an oven for drying. Drying may ensure polarizer film stays adhered to base film substrate  200 . 
     At step  312 , base film substrate  200  comprising a continuous surface of polarizer film may be laminated with layers of tri-acetyl cellulose (TAC) or other material to protect the polarizer film. At step  314 , a phase difference film (PF) may be applied to base film substrate  200 . Other chemicals may be applied and other mechanical processes may occur to complete the manufacture of polarizer film assembly  14 . 
     At step  502 , base film substrate  200  may be cut into individual polarizer film assemblies  14 , with each polarizer film assembly  14  being configured for assembly into display panel  100 . Cutting may include operating a cutter to cut along lines  404  and  406  to form polarizer film assemblies  402 . 
     Once cut, each polarizer film assembly  14  has a polarizer film assembly width substantially equal to the display assembly width and a polarizer film assembly height substantially equal to the display assembly height. However, polarizer film assemblies formed using traditional approaches may have polarizer film in front of optical sensors  22 . 
     After cutting base film substrate  200  into polarizer film assemblies  402 , at step  504 , polarizer film is removed such that base film substrate  200  does not have polarizer film covering areas corresponding to optical sensor  22 . Step  504  may require mechanical or chemical processes for removing polarizer film from base film substrate  400 . These processes may be time consuming and could damage a polarizer film assembly during the final processing steps, which is undesirable for manufacturing costs. 
     In a first approach, manufacturers use mechanical, chemical or optical processes to remove polarizer film or film from selected areas of polarizer film assemblies  402 . For example, one mechanical approach is to cut openings in the polarizer film assembly  402 . This approach generally occurs after the base film substrate has been laminated between other layers of material and cut to its final size. Thus, there is more material to remove and the process can damage the polarizer film assembly  402 . Also, unless there is a front layer  20  such as a bezel or cover glass, a user may see or feel a discontinuity on display panel  110 , which may be unappealing. 
     A chemical approach is to use a chemical to remove a polarizer film from selected areas of base film substrate  200 . However, using a chemical to remove a polarizer film from an area surrounded by an area with the same polarizer film is difficult. A chemical process may still leave a film or change the feel of polarizer film assembly  14  such that a user can see or feel a discontinuity or additional processing steps are necessary. 
     After step  504 , step  506  may include inspecting a polarizer film assembly to ensure polarizer film has been removed such that polarizer film assembly  14  does not cover or negatively affect optical sensor  22 . 
     The above disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments which fall within the true spirit and scope of the disclosure. Thus, to the maximum extent allowed by law, the scope of the disclosure is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.