Abstract:
An optical proximity sensor and housing for the same are disclosed. The housing is provided with at least two support structures and at least two modules. A first of the support structures transfers vertical forces applied to one end of a module to an opposite end of the opposite module. A second of the support structures inhibits a pivoting of the modules about the first support structure.

Description:
FIELD OF THE DISCLOSURE 
       [0001]    The present disclosure is generally directed toward optical proximity sensors and housings for the same. 
       BACKGROUND 
       [0002]    Many types of optical proximity sensors are currently available. The design of such sensors will often depend upon the application in which the sensor is employed. Typical fields of application for optical proximity sensors include, without limitation, motion detection, controllers for computing devices (e.g., optical mouse, optical finger navigation, rollerball navigation, etc.), industrial applications, medical applications, transportation applications, computing applications, communications applications, aerospace applications, and so on. 
         [0003]    As can be seen in  FIG. 1 , a typical optical proximity sensor  100  includes a substrate  104  upon which a light source  120  and a light detector  124  are mounted and housing  108  which provides a barrier between the light source  120  and light detector  124 . The housing  108  may also serve a dual purpose of protecting the light source  120  and light detector  124  as well as other electronic components of the optical proximity sensor  100  from external forces. 
         [0004]    In particular, the housing  108  may be designed to include a first module  112  and a second module  116 . The first module  112  may include a top surface and four sidewalls which completely encapsulate or enclose the light source  120 . Similarly, the second module  116  may include a top surface and four sidewalls which completely encapsulate or enclose the light detector  124 . The sidewall of the first module  112  which is adjacent to the sidewall of the second module  116  may be referred to as the inner sidewall of each module  112 ,  116 . In the embodiment depicted in  FIG. 1 , the inner sidewall of each module  112 ,  116  is used to form a u-bend feature  128  constructed of a folded material. The u-bend feature  128  serves two purposes. First, the u-bend reature  128  provides optical isolation between the light source  120  and light detector  124 . Second, the u-bend feature  128  is a structural member which serves as an interface between the housing  108  and the substrate  104 . More specifically, the u-bend feature  128  rests on the substrate  104  and is configured to convey vertical forces acting on the housing  108  laterally between modules  112 ,  116  as well as downwardly to the substrate  104 . The u-bend feature  128  provides a mechanism for transferring and redirecting vertical forces imparted on the housing during fabrication or use. 
         [0005]    Although not depicted in  FIG. 1 , the top surface of the first module  112  may comprise an aperture which allows light generated by the light source  120  to exit the housing  108  and reflect off of an object of interest. The top surface of the second module  116  may also comprise an aperture which allows light reflecting off of the object of interest (i.e., light originally emitted by the light source  120 ) to enter the cavity of the second module  116  and be detected by the light detector  124 . The light detected by the light detector  124  may then be subsequently processed or analyzed according to the application in which the optical proximity sensor  100  is employed. In some instances, the light detected by the light detector  124  may be converted into x-y user-motion data that is subsequently converted into commands which control a pointer or cursor on a computational device&#39;s user interface. 
         [0006]    As can be seen in  FIG. 2 , one issue which may arise with the optical proximity sensor  100  is that if the outer sidewalls  132 ,  136  of the modules  112 ,  116 , respectively, (i.e., the sidewalls which oppose the inner sidewalls or u-bend feature  128 ) are not machined to fit snugly around the substrate  104 , then the housing  108  may be prone to unwanted tilting. More specifically, if even a minor gap is present between one of the outer sidewalls  132 ,  136  and the outer edge of the substrate  104 , then the u-bend feature  128  may act as a pivot point for the housing  108 , which leads to unwanted tilting of the housing  108  with respect to the substrate  104 . Minor gaps may occur even if the housing  108  and substrate  104  are within manufacturing tolerances. In particular, if the housing  108  is at the high end of its manufacturing tolerance and the substrate  104  is at the lowest end of its manufacturing tolerance, a gap is created which can allow even more tilt to occur. 
         [0007]    Tilting of the housing  108  relative to the substrate  104  can have negative side effects including causing damage to the optical components  120 ,  124  of the optical proximity sensor  100  as well as leading to an unwanted shape and size of the optical proximity sensor  100 . If the optical proximity sensor  100  is improperly sized or has an improper shape, the optical proximity sensor  100  may not be suitable for its intended application and may, therefore, be labeled as defective. 
         [0008]    Other types of optical proximity sensors which are known in the art include, without limitation, those designed and manufactured by AVAGO TECHNOLOGIES™ such as HSDL-9100 surface-mount proximity sensors, APDS-9101 integrated reflective sensors, APDS-9120 integrated optical proximity sensors, APDS-9700, APDS-9800, etc. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The present disclosure is described in conjunction with the appended figures: 
           [0010]      FIG. 1  is a cross-sectional side view of an optical proximity sensor in accordance with embodiments of the prior art; 
           [0011]      FIG. 2  is a cross-sectional side view of an optical proximity sensor having an unwanted tilt in accordance with embodiments of the prior art; 
           [0012]      FIG. 3  is a first perspective view of an optical proximity sensor housing in accordance with embodiments of the present disclosure; 
           [0013]      FIG. 4  is a second perspective view of an optical proximity sensor housing in accordance with embodiments of the present disclosure; 
           [0014]      FIG. 5  is a side view of an optical proximity sensor housing in accordance with embodiments of the present disclosure; 
           [0015]      FIG. 6  is a cross-sectional perspective view of an optical proximity sensor housing in accordance with embodiments of the present disclosure; and 
           [0016]      FIG. 7  is a cross-sectional side view of an optical proximity sensor in accordance with embodiments of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    The ensuing description provides embodiments only, and is not intended to limit the scope, applicability, or configuration of the claims. Rather, the ensuing description will provide those skilled in the art with an enabling description for implementing the described embodiments. It being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the appended claims. 
         [0018]    With reference now to  FIGS. 3-6 , a housing  208  for use with an optical proximity sensor will be described in accordance with at least some embodiments of the present disclosure. FIGS.  3  and  4  show two perspective views of an optical proximity sensor housing  208  in accordance with embodiments of the present disclosure. The housing  208 , in some embodiments, is constructed of an optically opaque material. In some embodiments, the housing  208  is constructed of a single piece of material by folding a number of tabs until at least two individual modules  112 ,  116  have been created. The material chosen to construct the housing  208  may vary depending upon the application in which the optical proximity sensor is to be employed and other design considerations. In some embodiments, the housing  208  may be constructed of a single piece of metal, metal alloy, or similar compound. As some examples, the housing  208  may be constructed of mild steel, stainless steel, nickel-plated steel stock, aluminum, or the like. In some embodiments, the housing  208  may be constructed of a non-metal material. Specifically, any type of polymer may be used which is optically opaque and suitably pliable such that it can be formed to form the modules  112 ,  116 . Alternatively, a polymer may be injection molded or machined into the appropriate form of the housing  208  rather than folding a single sheet of material. Similarly, metal may be cast into the appropriate form of the housing  208  rather than folding a single sheet of material. Still further in the alternative, rather than folding a single sheet of material, multiple pieces of material may be glued, welded, clamped, or otherwise connected to one another to achieve the appropriate form of the housing  208 . In embodiments where a single sheet of material is used, any number of different techniques for establishing the initial features of housing in the sheet of material may be used, such as laser cutting, melting with arc welders, mechanical abrasion or cutting, and so on. 
         [0019]    In some embodiments, the folding methods used to construct the housing  208  may be similar to those described in U.S. Patent Publication No. 20100282951 to Costello et al., the entire contents of which are hereby incorporated herein by reference. Specifically, the housing  208  may be constructed from a single sheet of material (metal or non-metal) that comprises a plurality of tabs which are sequentially folded until the desired form of the housing  208  is achieved. 
         [0020]    In embodiments where a tab-based folding approach is used to manufacture the housing  208 , a number of tabs may be provided which ultimately become a specific feature of the housing  208 . As can be seen in  FIGS. 3 and 4 , the housing  208  may comprise a first module  112  and an adjacent module  116 . The first module  112 , in some embodiments, may comprise a top surface and four sidewalls. The top surface may comprise a first aperture  148  which is designed to allow light to enter and/or exit the cavity of the first module  112  (depending upon whether the first module  112  contains a light source or a light detector) in a predetermined fashion. 
         [0021]    The four sidewalls of the first module  112  may include an outer sidewall  132 , two lateral sidewalls  140  extending orthogonally from the outer sidewall  132 , and an inner sidewall that is included as part of a u-bend feature  128 . In some embodiments, the four sidewalls are configured in a rectangular or square shape, thereby creating a box or cube-shaped first module  112 . As can be appreciated, however, the first module  112  may be configured in other shapes without departing from the scope of the present disclosure. In particular, the first module  112  may be configured as a cylinder, an elongated cylinder (e.g., having an elliptical cross-section), a sphere, or a polygonal structure having more than four sidewalls. Accordingly, although the first module  112  is depicted as having four sidewalls, the first module  112  may have a greater or lesser number of sidewalls without departing from the scope of the present disclosure. 
         [0022]    In some embodiments, the sidewalls of the first module  112  may each correspond to a separate tab feature that has been folded. In some embodiments, the inner sidewall of the first module  112  may comprise a plurality of tabs that form some or all of the u-bend feature  128 . Furthermore, although the feature  128  is referred to herein as a u-bend feature  128 , one of ordinary skill in the art will appreciate that the feature  128  may be provided in any other shape (i.e., other than a “u” shape). The term “u-bend feature” is used herein primarily for ease of discussion. 
         [0023]    The lateral sidewalls  140  and outer sidewall  132  may correspond to tabs which were originally formed in a “T shape” with the top surface of the first module  112 . Each of the lateral sidewalls  140  and outer sidewall  132  may have been folded downwardly from the top surface of the first module  112  to form the cavity of the first module  112 . Similarly, the tabs used to form the inner sidewall may correspond to a first tab also extending from the top surface of the first module  112  as well as one or more additional tabs that were either extensions of the lateral sidewalls  140  or the first tab of the inner sidewall extending from the top surface. In other words, tabs extending from the lateral sidewalls  140  may be used to also form the inner sidewall and, therefore, the u-bend feature  128 . 
         [0024]    Similar to the first module  112 , the second module  116  may comprise a top surface and four sidewalls, although a greater or lesser number of sidewalls may be used to construct the second module  116 . The top surface of the second module  116  may comprise a second aperture  152  which is designed to allow light to enter and/or exit the cavity of the second module  116  (depending upon whether the second module  116  contains a light source or light detector) in a predetermined fashion. 
         [0025]    The four sidewalls of the second module  116  may include an outer sidewall  136 , two lateral sidewalls  144  extending orthogonally from the outer sidewall  136 , and an inner sidewall that is included as part of the u-bend feature  128 . The inner sidewalls of the first and second modules  112 ,  116  may be adjacent to one another and may also be parallel to one another. Similarly, the lateral sidewalls  140  of the first module  112  may be parallel with or in the same plane as the lateral sidewalls  144  of the second module  116 . The outer sidewall  132  of the first module  112  may be parallel to the outer sidewall  136  of the second module  116 . Thus, the housing  208  may have a generally rectangular shape, although other housing shapes may be employed. 
         [0026]    Similar to the first module  112 , the sidewalls of the second module  116  may each correspond to a separate tab feature that has been folded. In some embodiments, the inner sidewall of the second module  116  may comprise a plurality of tabs that form some or all of the u-bend feature  128 . In some embodiments, the u-bend feature  128  is constructed of an equal number of tabs from the first module  112  and the second module  116 . In other words, the number of tabs in the u-bend feature  128  that are attributable to the first module  112  equal the number of tabs in the u-bend feature  128  that are attributable to the second module  116 . Thus, the construction of the inner sidewalls of the first and second modules  112 ,  116  may be symmetrical. Alternatively, more tabs in the u-bend feature  128  are attributable to either the first module  112  or second module  116 . Also similar to the first module  112 , the lateral sidewalls  144  may correspond to tabs that have been folded downwardly from the top surface of the second module  116  to form the cavity of the second module  116 . 
         [0027]    One difference between the first module  112  and second module  116  is that the second module  116  may be provided with a multi-part outer sidewall  136 . More specifically, the outer sidewall  136  of the second module  116  may comprise a plurality of tabs which can be folded to form the cavity of the second module  116  as well as create a second support member for the housing  208  to interface with a substrate  104 . In some embodiments, the outer sidewall  136  of the second module  116  may comprise first and second bottom tab portions  156   a ,  156   b  which extend and fold from the lateral sidewalls  144 . The first and second bottom tab portions  156   a ,  156   b  may also have support extensions  158   a ,  158   b . The first and second support extensions  158   a ,  158   b  may be designed to fold into the cavity of the second module  116  to form a support member for the housing  208  rather than forming a wall of the second module  116 . In some embodiments, the outer sidewall  136  of the second module  116  may further comprise a top tab portion  160  which extends from the top surface of the second module  116 . The top tab portion  160  may have a length that is less than the length of any lateral sidewalls  140 ,  144 . The top tab portion  160  in combination with the first and second bottom tab portions  156   a ,  156   b  may form the portion of the outer sidewall  136  which defines the boundaries of the cavity of the second module  116 . 
         [0028]    As can be seen in  FIG. 4 , a gap  164  may be provided between the top tab portion  160  and the bottom tab portions  156   a ,  156   b  when folded. The gap  164  is provided as a mechanism for allowing some variances in machining of the housing  208 . Specifically, the top tab portion  160 , the bottom tab portions  156   a ,  156   b , and their support extensions  158   a ,  158   b , do not have to be precisely manufactured to allow the first and second bottom tab portions  156   a ,  156   b  to be folded and to allow the first and second support extensions  158   a ,  158   b  to be folded into the cavity of the second module  116 . In some embodiments, the support extensions  158   a ,  158   b , and therefore the gap  164 , are strategically placed on the outer sidewall  136  of the module that is configured to receive a light detector instead of a light source. Thus, any light which reaches the light detector from the light source reaches the light detector via the second aperture  152 . In some embodiments, the size of the gap  164  can range between about 50 microns to about 100 microns. 
         [0029]    As can be appreciated by those of ordinary skill in the art, the outer sidewall  136  of the second module  116  may have a greater or lesser number of tabs. Specifically, as one example, the outer sidewall  136  may comprise only a single bottom tab portion  156  which has one or more support extensions  158 . As another example, support extensions may be provided as part of the top tab portion  160  rather than the bottom tab portions  156   a ,  156   b . Thus, the top tab portion  160  may fold downwardly from the top surface of the second module  116  and then be folded a second time into the cavity of the second module  116 . 
         [0030]    In the embodiment depicted where the support extensions  158   a ,  158   b  are provided on the bottom tab portions  156   a ,  156   b , the order of folding operations for creating the outer sidewall  136  are as follows. The following order of operations may occur before or after the u-bend feature  128  has been created and/or before, during, or after the first module  112  has been created. First, the lateral sidewalls  144  are folded downwardly from the top surface of the second module  116 . Second, the bottom tab portions  156   a ,  156   b  are folded inwardly until they are substantially parallel with the edge of the top surface that meets the top tab portion  160 . Third, the support extensions  158   a ,  158   b  are folded inwardly toward the cavity of the second module  116 . In some embodiments, the support extensions  158   a ,  158   b  are folded until they are parallel with the top surface of the second module  116 . Finally, the top tab portion  160  is folded downwardly from the top surface of the second module  116  until it is parallel with or in the same plane as the first and second bottom tab portions  156   a ,  156   b.    
         [0031]      FIG. 5  shows a side view of a completed housing  208  in accordance with at least some embodiments of the present disclosure. As can be seen in  FIG. 5 , the bottom of the u-bend feature  128  may be in the same plane as the bottom of the other sidewalls of the first and second modules  112 ,  116 . 
         [0032]    The cross-sectional view of the completed housing  208  in  FIG. 6  shows how the support extensions  158   a ,  158   b  extend into the cavity of the second module  116 . In some embodiments, the length of a support extension  158   a  or  158   b  should be no longer than the total finished height of the housing  208  less the height of a bottom tab portion  156   a  or  156   b . In some embodiments, the length of a support extension  158   a  or  158   b  should be no longer than the total finished height of the housing  208  less the height of a bottom tab portion  156   a  or  156   b  and less the thickness of the top surface of the second module  116 . 
         [0033]    Referring now to  FIG. 7 , an optical proximity sensor  200  will be described in accordance with at least some embodiments of the present disclosure. The optical proximity sensor  200  comprises a substrate  104  and housing  208  as described with reference to  FIGS. 3-6 . The optical proximity sensor  200  may also comprise a light source  120  and a light detector  124  mounted on the substrate  104 . 
         [0034]    The substrate  104  may correspond to a Printed Circuit Board (PCB) that receives the light source  120  and light detector  124  as well as electronics for controlling operations of the optical proximity sensor  200 . 
         [0035]    The light source  120  may comprise any type of device capable of generating and transmitting light at one or more wavelengths. Suitable examples of a light source  120  include, without limitation, a Light Emitting Diode (LED), an infrared LED, a laser diode, or any other light-emitting device, array of light-emitting devices, or the like. One specific example of the light source  120  is a P/N mesa-type AlGaAs/GaAs infrared chip, manufactured by TYNTEK, having model number TK 114IRA. 
         [0036]    The light detector  124  may comprise any type of device, such as a photodetector, that is capable of receiving light energy and converting it into an electrical signal. Suitable examples of a light detector  124  include, without limitation, a PIN diode, a photo-diode, and a phototransistor. One specific example of the light detector  124  is a photodiode chip manufactured by TYNTEK having model number TK-043PD. 
         [0037]    The housing  208  effectively minimizes or eliminates cross-talk between the light source  120  and light detector  124 . Thus, the light detected by the light detector  124  should substantially correspond to light transmitted by the light source  120  that has exited the first aperture  148 , reflected off of an object of interest, and entered the second aperture  152 . 
         [0038]    The housing  208  also provides a structural component of the optical proximity sensor  200  that protects the light source  120 , light detector  124 , and any other electrical or sensitive componentry mounted on the substrate  104 . More specifically, the u-bend feature  128  and support extensions  158   a ,  158   b  provide multiple points of contact between the housing  208  and the substrate  104 . The support extensions  158   a ,  158   b  help to minimize unwanted tilting of the housing  208  with respect to the substrate  104 . Moreover, the support extensions  158   a ,  158   b  in combination with the u-bend feature  128  help to distribute forces imparted on the optical proximity sensor  200  during manufacture or use. In particular, vertical forces may be applied to the first and/or second modules  112 ,  116  of the housing  208  during manufacture of the optical proximity sensor  200 . Stress testing of the housing  208  has indicated that the maximum displacement of the top surface of both modules  112 ,  116  occur around the apertures  148 ,  152 . During the above-noted testing, a 5N vertical load was applied to the top surface of the second module  116  and the outer edge of the second module  116  was only displaced by 0.004 mm. Under a 20N similarly situated vertical load, the outer edge of the second module  116  was only displaced by 0.015 mm, which is still an acceptable amount of displacement and tilt for most applications. Because the support extensions  158   a ,  158   b  rest on the top surface of the substrate  104 , the housing  208  does not have to be precisely manufactured to have a snug fit with the substrate. 
         [0039]    Once the housing  208  has been formed, the light source  120  and light emitter driving circuitry may be mounted in the first module  112 . Similarly, the light detector  124  and light sensing circuitry may be mounted in the second module  116 . The substrate  104  may then be disposed beneath the housing  208  and operably connected to the light emitter driving circuit and light sensing circuit to yield an operative proximity sensor  200 . The completed optical proximity sensor  200  may be incorporated into any number of devices, such as a cellular phone, a Personal Digital Assistant (PDA), a laptop computer, a notebook computer, a desktop computer, a netbook, a tablet device, an electronic book reader, or the like. 
         [0040]    Specific details were given in the description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, circuits may be shown in block diagrams in order not to obscure the embodiments in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments. 
         [0041]    While illustrative embodiments of the disclosure have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed, and that the appended claims are intended to be construed to include such variations, except as limited by the prior art.