Abstract:
A dual-channel optical navigation system with vertically aligned sensors. The dual-channel optical navigation system includes a circuit board, a contact navigation sensor, and a free-space navigation sensor. The circuit board mechanically supports and electrically connects multiple navigation sensors on opposing sides of the circuit board. The contact navigation sensor is coupled to a first side of the circuit board. The contact navigation sensor generates a contact navigation signal based on contact navigation images of a contact navigation surface approximately adjacent to the dual-channel optical navigation system. The free-space navigation sensor is coupled to a second side of the circuit board. The free-space navigation sensor generates a free-space navigation signal based on free-space navigation images of an operating environment of the dual-channel optical navigation system.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    An optical navigation device is used to track the relative motion of a surface or object. Optical navigation is done by illuminating the surface or object and tracking its motion by analyzing the difference of two images recorded by an image sensor over a relatively short time frame. This concept can be witnessed, for example, in an optical computer mouse. As the mouse is moved across a tabletop or other surface, the relative motion is tracked and a navigation signal is generated. 
         [0002]      FIG. 1  depicts a conventional optical navigation system  10 . In particular, the optical navigation system  10  is a contact optical navigation system. The navigation system  10  includes a light source  12 , a lens  14 , and a sensor package  16 . The light source  12 , which generates light, is oriented at an angle with respect to a navigation surface  18 . The light that is emitted by the light source  12  is directed through the lens  14  to the navigation surface  18 . The navigation surface  16  reflects the light back through the lens  14  and into the sensor package  16 . The angular configuration of the optical navigation system  10  to achieve reflection of the light on the navigation surface  16  consumes space and restricts the ability to incorporate the system in various spatially-constrained applications. This configuration of the conventional optical navigation system  10  also confines the optical navigation system  10  to contact navigation applications in close proximity to the navigation surface  18 . 
       SUMMARY OF THE INVENTION 
       [0003]    Embodiments of a system are described. In one embodiment, the system is a dual-channel optical navigation system. One embodiment of the dual-channel optical navigation system includes a circuit board, a contact navigation sensor, and a free-space navigation sensor. The circuit board mechanically supports and electrically connects multiple navigation sensors on opposing sides of the circuit board. The contact navigation sensor is coupled to a first side of the circuit board. The contact navigation sensor generates a contact navigation signal based on contact navigation images of a contact navigation surface approximately adjacent to the dual-channel optical navigation system. The free-space navigation sensor is coupled to a second side of the circuit board. The free-space navigation sensor generates a free-space navigation signal based on free-space navigation images of an operating environment of the dual-channel optical navigation system. Other embodiments of the system are also described. 
         [0004]    Embodiments of an apparatus are also described. In one embodiment, the apparatus is an optical navigation device. The optical navigation device includes a circuit board, a contact navigation sensor, a light source, and a light pipe. The circuit board mechanically supports and electrically connects multiple navigation sensors on opposing sides of the circuit board. The contact navigation sensor is coupled to a first side of the circuit board. The contact navigation sensor generates a contact navigation signal based on contact navigation images of a contact navigation surface approximately adjacent to the optical navigation device. The light source is also coupled to the first side of the circuit board. The light source illuminates the contact navigation surface. The light pipe transmits the light from the light source to the contact navigation surface and directs reflected light from the contact navigation surface to the contact navigation sensor. Other embodiments of the apparatus are also described. 
         [0005]    Embodiments of a method are also described. In one embodiment, the method is a method of making a dual-channel optical navigation system. The method includes mounting a contact navigation sensor to a first side of a circuit board. The contact navigation sensor generates a contact navigation signal in a contact operation mode. The method also includes mounting a light pipe to the first side of the circuit board. The light pipe redirects light from a contact navigation surface approximately 90 degrees toward the contact navigation sensor. The method also includes mounting a free-space navigation sensor to a second side of the circuit board. The free-space navigation sensor generates a free-space navigation signal in a free-space operation mode. Other embodiments of the method are also described. 
         [0006]    Other aspects and advantages of embodiments of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrated by way of example of the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  depicts a cross-sectional view of a conventional optical navigation system. 
           [0008]      FIG. 2   a  depicts a schematic diagram of one embodiment of a dual-channel optical navigation system. 
           [0009]      FIG. 2   b  depicts an exploded view of another embodiment of the dual-channel optical navigation system of  FIG. 2   a.    
           [0010]      FIG. 3  depicts a cross-sectional view of another embodiment of the dual-channel optical navigation system of  FIG. 2   a.    
           [0011]      FIG. 4  depicts a schematic flow chart diagram of one embodiment of a method of making a dual-channel optical navigation system. 
           [0012]      FIG. 5  depicts a schematic block diagram of one embodiment of a dual-channel optical navigation system. 
       
    
    
       [0013]    Throughout the description, similar reference numbers may be used to identify similar elements. 
       DETAILED DESCRIPTION 
       [0014]      FIG. 2   a  depicts a schematic diagram of one embodiment of a dual-channel optical navigation system  100 . As depicted in  FIG. 2   a,  the dual channel optical navigation system  100  includes a light pipe  102 , a spacer  104 , a circuit board  106 , and a protective housing  108 . The light pipe  102  may be made of glass, plastic, or other light transmitting material. The light pipe  102  is mounted to the circuit board  106  over the spacer  104 . The spacer  104  is also mounted to the circuit board  106 . The protective housing  108  is mounted to the opposite side of the circuit board  106 . In one embodiment, the components are bonded to the circuit board  106  using adhesive. In another embodiment, the components are joined using fasteners. Although certain component parts are shown in conjunction with the optical navigation system  100  of  FIG. 2   a,  other embodiments may include fewer or more component parts, or equivalent parts to perform fewer or more contact navigation and free-space navigation functions. Additionally, while the components of the optical navigation system  100  are shown in  FIG. 2   a  as being separate components, some of these components may be integrated. In some embodiments, every component of the optical navigation system  100  may be integrated. 
         [0015]      FIG. 2   b  depicts an exploded view of another embodiment of the dual-channel optical navigation system of  FIG. 2   a.  As illustrated in  FIG. 2   b,  the dual-channel optical navigation system  100  includes the light pipe  102 , the spacer  104 , a contact navigation channel aperture  110 , a light source channel aperture  112 , the circuit board  106 , a light source  116 , a contact navigation sensor  114 , a free-space lens structure  118 , a free-space navigation lens  120 , and the protective housing  108 . 
         [0016]    In one embodiment, the contact navigation channel aperture  110  is positioned to allow light to fall incident on the contact navigation sensor  114 . In one embodiment, the contact navigation channel aperture  110  may be round in geometry. In other embodiments, the contact channel aperture  110  may have a geometry to produce an optical stop effect to eliminate aberrations in the light which passes to the contact navigation sensor  114 . In one embodiment, the contact navigation channel aperture  110  may be made of light transmissive material, for example, glass or plastic. Alternatively, the contact navigation channel aperture  110  may be an air gap through the spacer  104 . 
         [0017]    The depicted light source channel aperture  112  is configured to pass light from the light source  116  into the light pipe  102 . In one embodiment, the light source channel aperture  112  may be made of light transmissive material. Alternatively, the light source channel aperture  112  may be an air gap through the spacer  104 . In one embodiment, the light source channel aperture  112  may be configured to allow a percentage of the light from the light source  116  to pass into the light pipe  102 . In another embodiment the light source channel aperture  112  may be configured to direct all or substantially all of the light from the light source  116  into the light pipe  102 . 
         [0018]    The contact navigation sensor  114  of  FIG. 2   b  is depicted on the surface of the circuit board  106 . In one embodiment, the contact navigation sensor  114  is bonded to the circuit board  106 . In some embodiments, the contact navigation sensor  114  receives light and generates a contact navigation signal corresponding to the received light. In one embodiment, the contact navigation sensor  114  is a complementary metal-oxide semiconductor (CMOS) class sensor. In some embodiments, the light source  116  is coupled to the circuit board  106 . The light source  116  is configured to generate light. In some embodiments, the light source  116  is configured to generate light of a certain wavelength or range of wavelengths. In one embodiment, the light source  116  is a light-emitting diode (LED). In another embodiment the light source  116  is a vertical cell surface-emitting laser (VCSEL). Other embodiments may implement other types of light sources. 
         [0019]    The free-space lens structure  118  of  FIG. 2   b  includes the free-space navigation lens  120 . In one embodiment, the free-space lens structure  118  mechanically supports the free-space navigation lens  120 . In another embodiment, the free-space lens structure  118  and the free-space navigation lens  120  are integrated in a unitary structure. The free-space navigation lens  120  is made of glass, plastic, or other light transmitting material. The free-space navigation lens  120  may have different geometries to apply different optical effects to the light incident on the surface of the free-space navigation lens  120 . In general, the free-space navigation lens  120  collects incident ambient light and directs it towards a free-space navigation sensor  122  (see  FIG. 3 ). 
         [0020]      FIG. 3  depicts a cross-sectional view of another embodiment of the dual-channel optical navigation system  100  of  FIG. 2   a.  The dual-channel optical navigation system  100  depicted in  FIG. 3  is positioned relative to a contact navigation surface  126 . The dual-channel optical navigation system  100  includes the light pipe  102 , the spacer  104 , the circuit board  106 , and the protective housing  108 . The light pipe  102  includes a first lens portion  124  and a second lens portion  128 . Each of the lens portions  124  and  128  includes a corresponding reflective surface, namely the first reflective surface  130  and the second reflective surface  132 , respectively. 
         [0021]    In one embodiment, the dual-channel optical navigation system  100  is used in a contact navigation operating mode. In some embodiments, light from the light source  116  passes through the light source channel aperture  112  (see  FIG. 2   b ) and enters the first lens portion  124  of the light pipe  102 . The light is then reflected off the first reflective surface  130  and is directed by the first lens portion  124  towards the contact navigation surface  126 . The light is reflected off the contact navigation surface  126  and transmitted by the first lens portion  124  to the second lens portion  128 . In some embodiments, the first reflective surface  130  is oriented to provide total internal reflection of the light from the light source  116 . In some embodiments, the first lens portion  124  directs the reflected light from the contact navigation surface  126  and refracts the light toward the second lens portion  128 . The light from the contact navigation surface  126  is then reflected by the second reflective surface  132  of the second lens portion  128 . In some embodiments, the reflected light from the contact navigation surface  126  undergoes total internal reflection at the second reflective surface  132  of the second lens portion  128 . The second lens portion  128  directs the light through the contact navigation channel aperture  110  (see  FIG. 2   b ). The light is then detected by the contact navigation sensor  114 . 
         [0022]    In one embodiment the first reflective surface  130  is oriented to cause total internal reflection of the light generated by the light source  116 . For example, in an embodiment, the orientation angle for the first and second reflective surfaces  130  and  132  is about 45 degrees. In some embodiments, the first reflective surface  130  and the second reflective surface  132  are parallel. 
         [0023]    In some embodiments, the dual-channel optical navigation system  100  of  FIG. 3  is used in a free-space navigation operating mode. In some embodiments, the protective housing  108  encloses the free-space navigation lens  120 . The free-space navigation lens  120  gathers light from an object or surface and generates a corresponding free-space navigation signal. The light is directed by the free-space navigation lens  120  to the free-space navigation sensor  122 . In one embodiment, the free-space navigation lens  120  applies a convergence factor to the light. In another embodiment, the free-space navigation lens  120  applies a magnification factor to the light incident on the free-space navigation sensor  122 . In one embodiment the free-space navigation lens  120  includes multiple optical lenses to apply an optical effect to the light. 
         [0024]    In one embodiment, the free-space navigation sensor  122  and the contact navigation sensor  114  are mounted to opposite sides of the circuit board  106 . In this way, the free-space navigation sensor  122  and the contact navigation sensor  114  face opposite directions. In one embodiment, the circuit board  106  is oriented substantially perpendicular to the navigation surface  126 . In one embodiment, the vertical orientation of the circuit board  106  reduces, minimizes, or eliminates the horizontal distance between illumination and imaging channels because the light incident on the contact navigation surface  126  travels through the same vertical light pipe  102 . Embodiments of this vertical orientation also reduce, minimize, or eliminate illumination angles and imaging angles depicted in  FIG. 1 . 
         [0025]      FIG. 4  depicts a schematic flow chart diagram of one embodiment of a method of making a dual-channel optical navigation system. Although the method  140  is described in conjunction with the dual-channel optical navigation system  100 , other embodiments may be implemented with other types of optical navigation devices. 
         [0026]    At block  142 , the method  140  includes mounting a free-space navigation sensor  122  to a first side of a circuit board  106 . In one embodiment the free-space navigation sensor  122  is a pre-packaged integrated circuit (IC) bonded to the circuit board  106 . In another embodiment, the free-space navigation sensor  122  is a bare IC die bonded to the circuit board  106 . At block  144 , the method  140  includes mounting a contact navigation sensor  114  to a second side of the circuit board  106 . In one embodiment, the contact navigation sensor  114  is a pre-packaged IC bonded to the circuit board  106 . In another embodiment, the contact navigation sensor  114  is a bare IC die bonded to the circuit board  106 . At block  146 , the method  140  includes mounting a light source  116  to the second side of the circuit board  106 . In one embodiment, the light source  116  is a LED. In another embodiment, the light source  116  is a VCSEL. 
         [0027]    At block  148 , the method  140  includes mounting a free-space lens structure  118  to the first side of the circuit board  106 . In one embodiment, the free-space lens structure  118  includes the free-space navigation lens  120 . In some embodiments, the free-space lens structure  118  and the free-space navigation lens  120  are integrated in a unitary structure. At block  150 , the method  140  includes mounting a light pipe  102  to the second side of the circuit board  106 . In some embodiments, the light pipe  102  is separated from the circuit board  106  by a spacer  104 . In one embodiment, the spacer  104  and the light pipe  102  are integrated in a unified structure. 
         [0028]      FIG. 5  depicts a schematic block diagram of one embodiment of an optical navigation system  160 . The illustrated optical navigation system  160  includes an optical navigation device  162  and a contact navigation surface  126 . The optical navigation device  162  emits a light signal which is at least partially reflected by the contact navigation surface  126 . The optical navigation device  162  detects the reflected light signal and processes the reflected light signal, as described below. 
         [0029]    It should be noted that the distance between the optical navigation device  162  and the contact navigation surface  126  may vary depending on the application for which the optical navigation device  162  is used. In contact navigation operating mode, the optical navigation device  162  may be relatively close to the contact navigation surface  126 . For example, the optical navigation device  162  may be in physical contact with the contact navigation surface  126 , or the optical navigation device  162  may be within a few centimeters or inches of the contact navigation surface  126 . Alternatively, in free-space operating mode, the optical navigation device  162  may be relatively far from the contact navigation surface  126 . For example, the optical navigation device  162  may operate outside of the free-space optical range. 
         [0030]    The depicted optical navigation device  162  includes an optical navigation circuit  166  and a microcontroller  168 . Other embodiments may include fewer or more components. 
         [0031]    The depicted optical navigation circuit  166  includes an image acquisition system (IAS)  170 , a digital signal processor (DSP)  172 , and a driver  174 . In one embodiment, the driver  174  of the optical navigation circuit  166  controls the operation of the light source  116  (see  FIG. 3 ) to generate the light signal that is transmitted to the contact navigation surface  126 . The reflected light signal is then received and detected by the image acquisition system  170 . In the illustrated embodiment, the dual-channel optical navigation device  100  includes multiple navigation sensors, as described above. In one embodiment, the dual-channel optical navigation device  100  generates one or more electrical signals corresponding to incident light on one or more of the navigation sensors. 
         [0032]    The dual-channel optical navigation device  100  then transmits the signals to the analog-to-digital converter  178 . The analog-to-digital converter  178  converts the plurality of reconfigured electrical signals from analog signals to digital signals and then passes the digital signals to the digital signal processor  172 . 
         [0033]    After the digital signal processor  172  receives the digital form of the signals from the analog-to-digital converter  178  of the image acquisition system  170 , the digital signal processor  172  may perform additional processing using the reconfigured electrical signals. The digital signal processor  172  then transmits one or more signals to the microcontroller  168 . Exemplary types of signals transmitted from the digital signal processor  172  of the optical navigation circuit  166  to the microcontroller  168  include channel quadrature signals based on Ax and Ay relative displacement values. These signals, or other signals, may be indicative of a movement of the optical navigation device  162  relative to the contact navigation surface  126 . Other embodiments of the digital signal processor  172  may transmit other types of signals to the microcontroller  168 . In one embodiment, the microcontroller  168  implements a variety of functions, including transmitting data to and receiving data from a host computer system (not shown). 
         [0034]    Although the operations of the method herein are shown and described in a particular order, the order of the operations of the method may be altered so that certain operations may be performed in an inverse order or so that certain operations may be performed, at least in part, concurrently with other operations. In another embodiment, instructions or sub-operations of distinct operations may be implemented in an intermittent and/or alternating manner. 
         [0035]    Although specific embodiments of the invention have been described and illustrated, the invention is not to be limited to the specific forms or arrangements of parts so described and illustrated. The scope of the invention is to be defined by the claims appended hereto and their equivalents.