Abstract:
A headset for virtual reality applications includes an array of light emitting diodes (LEDs) emitting light captured by a camera included in a virtual reality system, allowing the virtual reality system to detect the position and orientation of the headset in three-dimensional space. To manufacture the headset, a flexible strip including a circuit having the LEDs is molded into an outer shell of the headset using a casting material that is transmissible to wavelengths of light transmitted by the LEDs. An interior surface of the outer shell of the headset is within a specified distance of the LEDs. The outer shell may also include fabric that is also molded into the outer shell in the same or in a similar process.

Description:
BACKGROUND 
       [0001]    This disclosure relates generally to manufacturing processes, and more specifically to overmolding a light emitting diode (LED) array into a casting material. 
         [0002]    Virtual reality systems rely on accurately tracking users to provide realistic content to the users. Many virtual reality systems track users by mounting light emitting diodes (LEDs) onto a headset worn by a user that presents virtual reality content to a user so a camera included in the virtual reality system may detect the position and orientation of the headset in three-dimensional space based on the light signals transmitted by the LEDs and captured by the camera. Current manufacturing techniques manually place a flexible array of LEDs onto a headset and affix the flexible array of LEDs to the headset with glue. However, manually affixing and adhering flexible arrays of LEDs to headsets result in high labor costs, greater variation in positioning of the LEDs on the headsets, and additional material between the flexible array of LEDs and the surface of the headset. Greater variation in the positions of LEDs on the headset may impair calibration of the virtual reality system to a position of the headset, which impairs subsequent tracking of the headset by the virtual reality system. Errors in tracking the headset may reduce the accuracy or quality of content provided via the headset by the virtual reality system. 
         [0003]    Additionally, some headsets may have fabric attached to an outer surface of the headsets. Conventional manufacturing processes wrap the fabric around the headset after the headset has been molded. However, this is labor-intensive and imprecise, resulting in low yields and increased risk of deformation from creep. 
       SUMMARY 
       [0004]    A headset for virtual reality applications includes an array of light emitting diodes (LEDs) emitting light captured by a camera included in a virtual reality system, allowing the virtual reality system to detect the position and orientation of the headset in three-dimensional space. To manufacture the headset, a flexible strip including a circuit having the LEDs is molded into an outer shell of the headset using a casting material (e.g., resin) that is transmissible to wavelengths of light transmitted by the LEDs. When manufacturing the headset, a flexible array of LEDs is attached to a surface of a molding structure and a mold is assembled by positioning an additional molding structure proximate to the molding structure. A surface of the additional molding structure is within a specified distance of the flexible array of LEDs so the LEDs are within the specified distance of an interior surface of the outer shell of the headset. The casting material is inserted into the assembled mold to form the headset. The outer shell may also include fabric that is also molded into the outer shell in the same or in a similar process. Molding the LEDs into the outer shell improves manufacturing tolerance and reduces labor in the manufacturing process. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1A  is an isometric view of an outside of an outer shell of a virtual reality headset, according to one embodiment. 
           [0006]      FIG. 1B  is an isometric view of an inside of an outer shell of a virtual reality headset, according to one embodiment. 
           [0007]      FIG. 2  is a flowchart for an overmolding process, according to one embodiment. 
           [0008]      FIG. 3A  is an example of attaching a flexible array of light emitting diodes (LEDs) to a mold, according to one embodiment. 
           [0009]      FIG. 3B  is an example of casting material pouted into a mold to which a flexible array of light emitting diodes (LEDs) has been attached, according to one embodiment. 
           [0010]      FIG. 3C  is a flexible array of light emitting diodes (LED) overmolded into a casting material, according to one embodiment. 
       
    
    
       [0011]    The figures depict various embodiments for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles described herein. 
       DETAILED DESCRIPTION 
     Overview 
       [0012]    An outer shell of a virtual reality headset may include light emitting diodes (LEDs) embedded in a casting material to aid in calibration. This outer shell may be made through, which is is a method of co-molding where an object is molded into a single side of a casting material. In addition to using less casting material, which results in a lighter outer shell, using overmolding to create the outer shell of the virtual reality headset also reduces labor costs and allows more precise placement or LEDs in the outer shell of the headset. 
       Example Outer Shell 
       [0013]      FIG. 1A  shows an external view of an embodiment of an outer shell  100  of a virtual reality headset, while  FIG. 1B  shows the inside of the outer shell  100 . The outer shell  100  is shaped so it can comfortably fit over a user&#39;s face and enclose necessary electronics. Accordingly, the outer shell  100  has front, top, bottom, left and right surfaces. Components for providing content to a user via the virtual reality headset are included in the outer shell  110 . For example, electronic components for providing content are positioned proximate to an interior of the front surface of the outer shell, allowing a user to position the electronic components in a position relative to the user&#39;s face to view content presented by the electronic components. The outer shell  100  and any attached components may block various wavelengths of light (e.g., wavelengths corresponding to visible light) to prevent the wavelengths of light from impairing the content presented by the electronic components included in the outer shell  110 . 
         [0014]    As shown in  FIG. 1B , the outer shell  100  comprises a flexible array of light emitting diodes (LEDs)  140  molded into a housing  120 . The housing is made of a casting material  180 , such as resin; however, in other embodiments, the casting material  180  may be any suitable material. The casting material  180  is transmissible to certain wavelengths of light. For example, the casting material  180  is transmissible to wavelengths of light generated by the LEDs in the flexible array of LEDs. The casting material  180  may also be opaque to certain wavelengths of light. In various embodiments, the casting material  180  is transmissible to wavelengths of light generated by the flexible array of LEDs and opaque to other wavelengths. For example the casting material  180  is transmissible to infrared wavelengths and opaque to wavelengths corresponding to visible light. The housing  120  may have raised and/or recessed features, which may be used to add additional functionality, display a company logo, or increase aesthetic appeal. In various embodiments, the housing  120  may have rubber contact points on the top and bottom surfaces, allowing a user to better grip the virtual reality headset. 
         [0015]    In some embodiments, fabric is included on the exteriors of the outer shell  100 . The fabric may be partially embedded into the housing  120  or secured to the housing  120  with adhesive. Alternatively, the fabric may be fully or partially overmolded into the housing  120  as further described below. In some embodiments, the fabric may be secured to the housing  120  by molding the casting material  180  through openings in the fabric, creating molded pins. The electromagnetic transmission properties of the fabric may match those of the casting material  180  used for the housing  120 . For example, the fabric blocks wavelengths of light corresponding to visible light while transmitting infrared wavelengths of light. Additionally, portions of the housing  120  may be cut out and replaced with fabric to reduce the amount of casting material  180  used, which reduces the weight of the outer shell  100 . Alternatively, the housing  120  may be thinner in the areas where including fabric, rather than being cut out. The thinner areas of the housing  120  may have patterns that maintain the structural integrity of the outer shell  100  while reducing its weight and the amount of casting material  180  used. 
         [0016]    The flexible array of LEDs  140  embedded in the housing  120  comprises a flexible circuit and one or more LEDs  150 . The flexible circuit allows the flexible array of LEDs  140  to be shaped according to the form of the outer shell  100  and allows the LEDs  150  to be connected in a single circuit that may be premade in a specific configuration before the housing  120  is molded. In various embodiments, the LEDs  150  may protrude from the surface of the flexible circuit. The LEDs  150  emit wavelengths of infrared light in some embodiments, and may emit any suitable wavelengths of light in various embodiments. Light emitted from each LED  150  of the flexible array of LEDs  140  may be focused by an encircling clip to aid in calibration of the virtual reality headset by providing a smaller area or light for detection by the calibration system. The encircling clips may block wavelengths of light emitted by the flexible array of LEDs, minimizing light emitted by an LED  150  overlapping with light emitted by another LED  150 . For example, encircling clips block wavelengths of infrared light. 
         [0017]    The flexible array of LEDs  140  is molded into the housing  120  so a portion of the flexible array of LEDs  140  is embedded in the housing  120  while another portion is not embedded. For example, an upper portion of the flexible array of LEDs is molded into the housing  120 , while a lower portion of the flexible array of LEDs  140  is not. Hence, an inner surface of the outer shell  100  includes the housing  120  and the flexible array of LEDs, while an outer surface of the outer shell includes only the housing  120 . For the portion of the flexible array of LEDs molded into the housing  120 , a specified thickness of the casting material  180  covers the flexible array of LEDs. The specified thickness may be predetermined in various embodiments. The thickness of the layer of casting material  180  covering flexible the array of LEDs  140  may be uniform across the flexible array of LEDs or may vary for different areas of the flexible array of LEDs. In one embodiment, the housing  120  may be flush with the top of the LEDs  150  so the flexible array of LEDs is covered by a small thickness of the casting material  180 . Alternatively, the thickness of the casting material  180  covering flexible array of LEDs may be more significant (e.g., several millimeters or more). 
       Process for Overmolding Outer Shell of Headset 
       [0018]      FIG. 2  is an example of a method for including a flexible array of light emitting diodes (LEDs) into a housing. In various embodiments, the method may include different and/or additional steps than those described in conjunction with  FIG. 2 . Additionally, in some embodiments, steps of the method may be performed in different orders. 
         [0019]    Initially, the flexible array of LEDs is secured  210  to a surface of a molding structure. For example, the flexible array of LEDs  140  is secured to a surface  210  of a molding structure by a clip that is also molded into a housing  120 , such as an encircling clip. Alternatively, the flexible array of LEDs  140  is secured  210  to a surface of the molding structure through suction (e.g., through creating a vacuum). For example, the surface of the molding structure includes one or more openings, allowing a pressure difference between the surface of the molding structure and another surface of the molding structure parallel to the surface to secure  210  the flexible array of LEDs  140  to the surface of the molding structure (e.g., through creating a vacuum). 
         [0020]    After securing  210  the flexible array of LEDs  140  to the surface of the molding structure, the mold is assembled  220  using one or more additional portions. For example, an additional portion of the molding structure is positioned relative to the portion of the molding structure to which the flexible array of LEDs  140  is secured  210 . In various embodiments, the additional portion of the molding structure is positioned so there is a specified distance between the flexible array of LEDs  140  and an inner surface of the additional molding structure parallel to the surface of the molding structure to which the flexible LED array is secured  210 . Hence, the assembled mold includes a specified distance between the flexible array of LEDs  140  and a surface of an additional molding structure. 
         [0021]    A casing material that is transmissible to one or more wavelengths of light emitted by the flexible LED array having is inserted  230  into the assembled mold. The casting material can be inserted  230  via casting, injection and/or thermoforming. The mold is subsequently removed  240  to produce the housing  120  in which the flexible LED array is included. In some embodiments, fabric is secured  210  to the surface of the molding structure with the flexible array of LEDs  140  to include the fabric in the housing  120  along with the flexible array of LEDs  140 . Alternatively, the fabric may be molded to the housing  120  separately from the flexible array of LEDs  140 . If the fabric is separately molded, the flexible array of LEDs  140  may be overmolded or co-molded into the housing  120  as described above in conjunction with  FIG. 2 . The fabric may then be secured to a surface of the housing  120 , so the surface of the housing  120  acts as the molding structure described above in conjunction with  FIG. 2 . An alternative molding structure, or the additional molding structure, is then positioned relative to the surface of the housing  120  and a casting material is inserted into an opening separating the surface of the housing  120  to which the fabric is secured from the alternative molding structure. Fabric for inclusion in the housing  120  may include one or more openings, so the casting material travels through the opening when inserted into an assembled mold, causing the casting material to form molded pins to secure the fabric. 
         [0022]      FIG. 3A  is an example of an assembled mold  300  with a flexible array of light emitting diodes (LEDs)  140  secured to a surface of a portion of a molding structure  310 . The mold  300  also includes an additional molding structure  320  having a surface that is separated from the flexible array of LEDs  140  by a specified distance  340 . In various embodiments, the distance  340  between the surfaces of the additional molding structure  320  to the flexible array of LEDs  140  is measured between the surface of the additional molding structure  320  and a surface of an LED  150  included in the flexible array of LEDs  140 . 
         [0023]    A casting material  180 , such as resin, is inserted into the mold  300  as shown in  FIG. 3B  and fills an area between the surface of the portion of the molding structure  310  to which the flexible array of LEDs  140  is secured and a surface of the additional molding structure  320  to produce the housing  180 . After the casting material  180  has set or cured, the mold  300  is removed, resulting in the housing  120 .  FIG. 3C  shows the resulting housing  120  after removal of the mold  300  from the casting material  180 . As shown in  FIG. 3C , the housing  120  includes the flexible array of LEDs  140  with the specified distance  340  between a surface of the flexible array of LEDs  140  and an interior surface of the housing that is parallel to the surface of the flexible array of LEDs  140 , which corresponds to the surface of the additional molding structure  320  in  FIGS. 3A and 3B   
       Summary 
       [0024]    The foregoing description of the embodiments of the invention has been presented for the purpose of illustration; it is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above disclosure. 
         [0025]    Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based hereon. Accordingly, the disclosure of the embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.