Abstract:
An optical navigation module for receiving control from an object disposed on an operation plane is provided. The optical navigation module includes a substrate defining a base plane that is perpendicular to the operation plane; a light source installed on the base plane of the substrate and configured to emit light to a side of the substrate; an optical structure installed at the side of the substrate; a light sensor installed on the base plane of the substrate; a light shield installed on the base plane of the substrate spatially separating the light source and the light sensor so that light emitted by the light source is not directly shed on the light sensor, the light shield having an aperture formed thereon; and a tactile switch for executing a command installed at a side of the light source that is opposite to the side facing the operation plane. The optical structure is configured to guide the light emitted from the light source to the object so that at least a portion of the light scattered by the object passes to the light sensor through the aperture on the light shield and forms a light intensity pattern on the light sensor.

Description:
FIELD OF THE PATENT APPLICATION 
       [0001]    The present patent application relates to an optical navigation module and more particularly to a side mounting optical navigation module that has a reduced thickness and wide applications. 
       BACKGROUND 
       [0002]    Optical navigation module is an essential component of consumer electronics requiring user input through a GUI (Graphical User Interface). As illustrated in  FIG. 7 , the typical key building blocks of an optical navigation module are a light sensor  701 , a light source  703 , a light shield  705  disposed around the light sensor  701 , an optical element  707  and a substrate  709  for mounting all the above elements. In a conventional design, the plane  710  defined by the substrate, the light source emission surface and the light sensor sensing surface is always facing or in parallel with the tracking surface  711  of the module, which imposes a limit on the thickness of the optical navigation module and in turn a limit on the application of the optical navigation module. 
       SUMMARY 
       [0003]    The present patent application is directed to an optical navigation module for receiving control from an object disposed on an operation plane. In one aspect, the optical navigation module includes a substrate defining a base plane that is perpendicular to the operation plane; a light source installed on the base plane of the substrate and configured to emit light to a side of the substrate; an optical structure installed at the side of the substrate; a light sensor installed on the base plane of the substrate; a light shield installed on the base plane of the substrate spatially separating the light source and the light sensor so that light emitted by the light source is not directly shed on the light sensor, the light shield having an aperture formed thereon; and a tactile switch for executing a command installed at a side of the light source that is opposite to the side facing the operation plane. The optical structure is configured to guide the light emitted from the light source to the object so that at least a portion of the light scattered by the object passes to the light sensor through the aperture on the light shield and forms a light intensity pattern on the light sensor. 
         [0004]    The optical structure may include a slanted surface configured for bending the light from the light source toward the object at the operation plane. The slanted surface may be applied with a reflective coating. The optical structure may include two lens surfaces disposed next to the slanted surface, one of the lens surfaces facing the light source, the other one of the lens surfaces facing the operation plane. The optical structure may include two discrete parts separated by a gap. One of the two discrete parts may include a slanted surface without any reflective coating. 
         [0005]    The optical structure may include a lens surface disposed next to the slanted surface, the lens surface facing the light source. The optical structure may further include an additional slanted surface configured for bending light coming from the other slanted surface toward the base plane. 
         [0006]    In another aspect, the optical navigation module includes a substrate defining a base plane that is perpendicular to the operation plane; a light source installed on the base plane of the substrate and configured to emit light to a side of the substrate; an optical structure installed at the side of the substrate; a light sensor installed on the base plane of the substrate; and a light shield installed on the base plane of the substrate spatially separating the light source and the light sensor so that light emitted by the light source is not directly shed on the light sensor, the light shield having an aperture formed thereon. The optical structure is an integral structure made by a light transmissive material, and is configured to guide the light emitted from the light source to the object so that at least a portion of the light scattered by the object is transmitted to the light sensor through the aperture on the light shield. 
         [0007]    The optical structure may include a slanted surface configured for bending the light from the light source toward the object at the operation plane. The slanted surface may be applied with a reflective coating. The optical structure may include a lens surface disposed next to the slanted surface, the lens surface facing the light source. The optical structure may further include an additional slanted surface configured for bending light coming from the other slanted surface toward the base plane. 
         [0008]    In yet another aspect, the optical navigation module includes a substrate defining a base plane that is perpendicular to the operation plane; a light source installed on the base plane of the substrate and configured to emit light to a side of the substrate; an optical structure installed at the side of the substrate; a light sensor installed on the base plane of the substrate; and a light shield installed on the base plane of the substrate spatially separating the light source and the light sensor so that light emitted by the light source is not directly shed on the light sensor, the light shield having an aperture formed thereon. The optical structure includes two discrete parts separated by a gap, being made by a light transmissive material, and being configured to guide the light emitted from the light source to the object so that at least a portion of the light scattered by the object is transmitted to the light sensor through the aperture on the light shield. 
         [0009]    The optical structure may include a slanted surface configured for bending the light from the light source toward the object at the operation plane. The optical structure may include two lens surfaces disposed next to the slanted surface, one of the lens surfaces facing the light source, the other one of the lens surfaces facing the operation plane. The slanted surface may be applied with a reflective coating. 
         [0010]    One of the two discrete parts may include a slanted surface without any reflective coating. The light source may be an infrared light source. The refractive index of the light transmissive material may be between 1.56 and 1.7. 
     
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         [0011]      FIG. 1A  is a cross-sectional view of a side mounting optical navigation module according to an embodiment of the present patent application. 
           [0012]      FIG. 1B  illustrates a tactile switch and a rigid flex of the side mounting optical navigation module depicted in  FIG. 1A . 
           [0013]      FIG. 1C  is an exploded view of the side mounting optical navigation module depicted in  FIG. 1A . 
           [0014]      FIG. 2A  is a cross-sectional view of a side mounting optical navigation module according to another embodiment of the present patent application. 
           [0015]      FIG. 2B  illustrates a tactile switch and a rigid flex of the side mounting optical navigation module depicted in  FIG. 2A . 
           [0016]      FIG. 2C  is an exploded view of the side mounting optical navigation module depicted in  FIG. 2A . 
           [0017]      FIG. 3A  is a cross-sectional view of a side mounting optical navigation module according to yet another embodiment of the present patent application. 
           [0018]      FIG. 3B  illustrates a tactile switch and a rigid flex of the side mounting optical navigation module depicted in  FIG. 3A . 
           [0019]      FIG. 3C  is an exploded view of the side mounting optical navigation module depicted in  FIG. 3A . 
           [0020]      FIG. 4  is a cross-sectional view of a side mounting optical navigation module according to still another embodiment of the present patent application. 
           [0021]      FIG. 5  is a cross-sectional view of a side mounting optical navigation module according to still another embodiment of the present patent application. 
           [0022]      FIG. 6  is a cross-sectional view of a side mounting optical navigation module according to still another embodiment of the present patent application. 
           [0023]      FIG. 7  is a cross-sectional view of an optical navigation module according to a conventional design. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Reference will now be made in detail to a preferred embodiment of the side mounting optical navigation module disclosed in the present patent application, examples of which are also provided in the following description. Exemplary embodiments of the side mounting optical navigation module disclosed in the present patent application are described in detail, although it will be apparent to those skilled in the relevant art that some features that are not particularly important to an understanding of the side mounting optical navigation module may not be shown for the sake of clarity. 
         [0025]    Furthermore, it should be understood that the side mounting optical navigation module disclosed in the present patent application is not limited to the precise embodiments described below and that various changes and modifications thereof may be effected by one skilled in the art without departing from the spirit or scope of the protection. For example, elements and/or features of different illustrative embodiments may be combined with each other and/or substituted for each other within the scope of this disclosure. 
         [0026]      FIG. 1A  is a cross-sectional view of a side mounting optical navigation module according to an embodiment of the present patent application. Referring to  FIG. 1 , the side mounting optical navigation module includes a coherent infrared (IR) light source  101 , a sensor IC  109 , a light shield  107 , a lens block  106  and a substrate PCB (printed circuit board)  111  on which all other components are accommodated. The light shield  107  is made of light absorbing material and contains an aperture  108 . The sensor IC  109  is located in the enclosure of the light shield  107 . The lens block  106  encloses the light source  101 , the sensor IC  109  and the light shield  107 , and is positioned on the substrate  111 . The lens block  106  is made of a light transmissive material with high transparency for the wavelength bands of the optical signal generated by the IR light source  101 . Preferably, the refractive index of the light transmissive material is between 1.56 and 1.7. 
         [0027]    Light emitted from the coherent IR light source  101  is transformed to a collimated or near-collimated beam by the lens surface  102  and is bent by 90 degrees at the slanted surface  103  by total internal reflection and steered toward a tracking surface (or operation plane)  104  of the module. The distance from the light source  101  to the lens surface  102  could be less than 0.5 mm. The full distance from the IR light source  101  to the top of the slanted surface  103  could be controlled to be within 1 mm. The distance from the slanted surface  103  to the tracking surface  104  is variable since the light coming out from the slanted surface  103  is a parallel light beam. 
         [0028]    When an object  110  is present near the tracking surface  104 , a portion of the IR light emitted from the IR light source  101  is scattered back into the optical navigation module. A portion of the back-scattered light passes through an aperture  108  and forms a speckle pattern on the sensor IC  109 . The speckle pattern is detected by the sensor array  105  on the surface of the sensor IC  109 . It is understood, as described here and hereafter, the speckle pattern may be other types of light intensity patterns. It is further understood that the lens block  106  is illustrated in this embodiment as an exemplary optical structure that is configured to guide the light emitted from the light source  101  to the object  110  so that at least a portion of the light scattered by the object  110  passes to the light sensor  109  through the aperture  108  on the light shield  107  and forms a light intensity pattern on the light sensor  109 . 
         [0029]      FIG. 1B  illustrates a tactile switch and a rigid flex of the side mounting optical navigation module depicted in  FIG. 1A .  FIG. 1C  is an exploded view of the side mounting optical navigation module depicted in  FIG. 1A . Referring to  FIG. 1B  and  FIG. 1C , the side mounting optical navigation module can optionally include a tactile switch  121  and a rigid flex  122  installed at a side of the light source  101  that is opposite to the side facing the tracking surface  104 . When the finger presses on the tracking surface  104 , the tactile switch  121  can be closed and used to execute a certain selection command. All the electrical signals, including the movement information and the tactile switch signals are transferred to a processor through the rigid flex  122 . 
         [0030]      FIG. 2A  is a cross-sectional view of a side mounting optical navigation module according to another embodiment of the present patent application. Referring to  FIG. 2A , the optical navigation module includes a coherent infrared (IR) light source  201 , a sensor IC  211 , a light shield  207 , a lens block  209  and a substrate PCB  212 . The arrangement of these components is identical to the embodiment illustrated in  FIG. 1A  except for the design of the lens block  209 . 
         [0031]    Light emitted from the coherent IR light source  201  is collimated or near-collimated by the first lens surface  202  and is bent by 90 degrees at the slanted surface  203  by total internal reflection and steered toward the tracking surface  205  through the second lens surface  204  to form a larger illumination area. The distance from the light source  201  to the first lens surface  202  could be less than 0.5 mm. Full distance from the IR light source  201  to the top of the slanted surface  203  could be controlled within 1 mm. The distance from the second lens surface  204  to the tracking surface  205  is also within 1 mm. Thickness of the tracking surface (IR side cover)  205  is in the range of 0.5 mm to 1.5 mm depending on the module size requirement. The light spot size on the IR interface can be adjusted by adjusting the profile of the second lens  204  and the distance between the second lens  204  and the tracking surface  205 . As such, the optical navigation module in this embodiment can be applied to devices that require different widths of the optical navigation module. The light spot in this embodiment has a wider spatial distribution, which will reduce the sensor&#39;s lift off distance. 
         [0032]    When an object  210  is present near the tracking surface  205 , a portion of the IR light emitted from the IR light source  201  is scattered back into the module. A portion of the back-scattered light passes through the aperture  208  and forms a speckle pattern on the sensor IC  211  and is detected by the sensor array  206  on the surface of the sensor IC  211 . It is understood that the lens block  209  is illustrated in this embodiment as an exemplary optical structure that is configured to guide the light emitted from the light source  201  to the object  210  so that at least a portion of the light scattered by the object  210  passes to the light sensor  211  through the aperture  208  on the light shield  207  and forms a light intensity pattern on the light sensor  211 . 
         [0033]      FIG. 2B  illustrates a tactile switch and a rigid flex of the side mounting optical navigation module depicted in  FIG. 2A .  FIG. 2C  is an exploded view of the side mounting optical navigation module depicted in  FIG. 2A . Referring to  FIG. 2B  and  FIG. 2C , the optical navigation module can optionally include a tactile switch  221  and a rigid flex  222  installed at a side of the light source  201  that is opposite to the side facing the tracking surface  205 . When the finger presses on the tracking surface  205 , the tactile switch  221  can be closed and can be used to execute a certain selection command. All the electrical signals, including the movement information and the tactile switch signals are transferred to the processor through the rigid flex  222 . 
         [0034]      FIG. 3A  is a cross-sectional view of a side mounting optical navigation module according to yet another embodiment of the present patent application. Referring to  FIG. 3A , the optical navigation module includes a coherent infrared (IR) light source  301 , a sensor IC  311 , a light shield  307 , a lens block  309  and a substrate PCB  312 . The arrangement of these components is identical to the aforementioned embodiments except for the design of the lens block  309 . 
         [0035]    Light emitted from the coherent IR light source  301  is transformed to a collimated or near-collimated beam by a lens surface  302 , bent by 90 degrees at a first slanted surface  303  by total internal reflection, and steered toward the tracking surface  305  through a second slanted surface  304  so as to be bent toward the center of the module sensing region. The distance from the light source  301  to the lens surface  302  could be less than 0.5 mm. The full distance from the IR light source  301  to the top of the first slanted surface  303  could be controlled within 1 mm. The distance from the second slanted surface  304  to the tracking surface  305  is also within 1 mm depending on the module size and height requirements. The light spot size on the IR interface could be adjusted by adjusting the slant angle of the second slanted surface  304  as well as the distance between the second slanted surface  304  and the tracking surface  305 . As such, the optical navigation module in this embodiment can be applied in thinner devices. 
         [0036]    When an object  310  is present near the tracking surface  305 , a portion of the IR light emitted from the IR light source  301  is scattered back into the optical navigation module. A portion of the back-scattered light passes through the aperture  308  and forms a speckle pattern on the sensor IC  311  and is detected by the sensor array  306  on the surface of the sensor IC  306 . It is understood that the lens block  309  is illustrated in this embodiment as an exemplary optical structure that is configured to guide the light emitted from the light source  301  to the object  310  so that at least a portion of the light scattered by the object  310  passes to the light sensor  311  through the aperture  308  on the light shield  307  and forms a light intensity pattern on the light sensor  311 . 
         [0037]      FIG. 3B  illustrates a tactile switch and a rigid flex of the side mounting optical navigation module depicted in  FIG. 3A .  FIG. 3C  is an exploded view of the side mounting optical navigation module depicted in  FIG. 3A . Referring to  FIG. 3B  and  FIG. 3C , the optical navigation module can optionally include a tactile switch  321  and a rigid flex  322  installed at a side of the light source  301  that is opposite to the side facing the tracking surface  305 . When a finger of the user presses on the tracking surface  305 , the tactile switch  321  can be closed and can be used to execute a certain selection command. And all the electrical signals, including the movement information and tactile switch signals are transferred to the processor through the rigid flex  322 . 
         [0038]      FIG. 4  is a cross-sectional view of a side mounting optical navigation module according to still another embodiment of the present patent application. Referring to  FIG. 4 , the optical navigation module in this embodiment is similar to the embodiment depicted in  FIG. 1 , except that the lens surface  102  in  FIG. 1  is eliminated in this embodiment. To bend the light beam toward to the tracking surface  404 , a reflective coating is applied to the slanted surface  403  so that the slanted surface  403  becomes a mirror surface. Preferably, the sloping angle of the slanted surface  403  is 45 degrees. 
         [0039]      FIG. 5  is a cross-sectional view of a side mounting optical navigation module according to still another embodiment of the present patent application. Referring to  FIG. 5 , the optical navigation module in this embodiment is similar to the embodiment depicted in  FIG. 4 , except that the optical structure  509  is not continuous in this embodiment. More specifically, the optical structure  509  includes two discrete parts separated by a gap  511 . To bend the light beam toward to the tracking surface  504 , a reflective coating is applied to the slanted surface  503  so that the slanted surface  503  becomes a mirror surface. In addition, another slanted surface  506  without any reflective coating is added to guide the light toward the tracking surface  504 . Preferably, the sloping angle of the slanted surface  503  is  45  degrees. It is understood that the sensitive spot position on the tracking surface  504 , where the optical navigation module has a relatively high sensitivity for an object disposed nearby, can be adjusted by the sloping angle of the slanted surface  506 . 
         [0040]      FIG. 6  is a cross-sectional view of a side mounting optical navigation module according to still another embodiment of the present patent application. Referring to  FIG. 6 , the optical navigation module in this embodiment is similar to the embodiment depicted in  FIG. 2A , except that a portion of the lens block  209  (corresponding to the lens block  609  in  FIG. 6 ) is substituted by a slanted surface  606 . No reflective coating is needed in the lens block  609 . Both spot size and spot position can be adjusted and hence there is more room for sensitive functions. It is understood that in this embodiment, the light is bent by 90 degrees at the surface  603  by total internal reflection. It is further understood that the lens block  609  is illustrated in this embodiment as an exemplary optical structure that is configured to guide the light emitted from the light source to the object so that at least a portion of the light scattered by the object passes to the light sensor through the aperture on the light shield and forms a light intensity pattern on the light sensor. 
         [0041]    In the above embodiments, the optical navigation module is capable of being controlled by an object, for example, a user&#39;s finger, placed at an operation plane that is perpendicular to, instead of in parallel with or facing, the base plane defined by the substrate on which the light source and the light sensor are installed. As such, the optical navigation module has a reduced thickness and can be used not only by being placed in parallel to a display panel on a consumer device, but also by being installed to a side of the device, therefore having wide applications. 
         [0042]    While the present patent application has been shown and described with particular references to a number of embodiments thereof, it should be noted that various other changes or modifications may be made without departing from the scope of the present invention.