Abstract:
Well-designed absolutely fixing mechanisms are provided for optical mice to avoid loose engagement between the optical components and base plate in an optical mouse, and eliminate shifting and out-of-focus of the light path in the optical mouse, thereby improving performance of the optical mouse.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention is related generally to an optical mouse and, more particularly, to a light path stabilizing mechanism for optical mice. 
       BACKGROUND OF THE INVENTION 
       [0002]    Since the advent of twenty-first century, optical mice have replaced conventional roller ball mice in a wide range of applications owing to their advantages of flexibility in use and durability.  FIG. 1  is a simplified diagram showing the parts of an optical mouse. To facilitate mass production and assembly, the optical parts of an optical mouse are manufactured separately, and during assembly, a printed circuit board (PCB)  16  with an optical sensor chip  14  and a light source device  12  soldered thereon is assembled to an optical lens  18 , which is in turn assembled to a base plate  19  with a fool-proof structure  194  and a recess  192  on the base plate  19 , and then a light source mount  10  is fixed to the PCB  16  in a tight fit, thereby completing an optical mouse. 
         [0003]      FIG. 2  is a side view of the optical mouse shown in  FIG. 1  to depict the light path thereof. The light source device  12  is generally a red light emitting diode (LED), and the light emitted from the light source device  12  is refracted and reflected by the optical lens  18 , and then passes through an opening  196  to impinge obliquely on a plane where it is reflected back to the optical lens  18  to be imaged onto the optical sensor chip  14 . Different features and roughness of the desktop surface will result in different energy intensity of the reflected light to exhibit corresponding features in the image. When the optical mouse is moved, continuous patterns will be obtained in the optical sensor chip  14  which then, according to difference in positions of features of the continuous images, compares and analyzes each of the images to determine the moving direction and displacement of the optical mouse. In other words, imaging quality is a key factor that dominates performance of the optical mouse. Hence, when loose engagement or misalignment between individual parts of the optical mouse occurs, light reflected from the desktop surface will fail to follow the correct light path and travel to the optical sensor chip  14 . Consequently, the optical sensor chip  14  will retrieve a drifting or blurred image, leading to incorrect recognition of the image. 
         [0004]    As molds used by various manufacturers for producing the separate optical parts have non-uniform specifications, problems such as varied height of the mouse base plates, poor close-fit and poor fixation effect among individual components often arise. Consequently, the resulting mice tend to become loose in the Z-axis direction during operation, thereby causing shifting and out-of-focus of the light path. As an effort to improve these problems caused by a loose part(s), attempts have been made to combine individual optical components into an assembly by various means. As shown in  FIG. 3 , by use of a fixture  28 , an optical lens  26  and a PCB  22  having an optical sensor chip  20  and a light source device  24  soldered thereon are assembled tightly together to form an assembly  32 , which is then placed into a recess  305  on a base plate  30  to complete the assembling process. Alternatively, as shown in  FIG. 4 , optical components such as a PCB, an optical sensor unit, a light source device, an optical lens or the like are packaged into an enclosed optical module  42 , which is then placed into a recess  445  on a base plate  44  to complete the assembling process. 
         [0005]    Although the optical mice shown in  FIGS. 3 and 4  have most of the optical components fixed more properly and stably, engagement of the parts with the respective base plates is still accomplished by being simply placed therein. Moreover, to surely avoid that the recess  305  or  445  is too small to receive the assembly  32  or optical module  42 , manufacturers will necessarily produce the recess  305  or  445  on the base plate  30  or  44  to be slightly larger, so that the optical mice shown in  FIGS. 3 and 4  still suffer from the problem of loose engagement or misalignment between the assembly or module and the base plate. 
       SUMMARY OF THE INVENTION 
       [0006]    An object of the present invention is to improve the light path shifting of optical mice. 
         [0007]    According to the present invention, an optical mouse includes a base plate having an engagement mechanism, and an assembly formed by fixing a printed circuit board (PCB) having a light source device and an optical sensor chip soldered thereon and an optical lens together by a fixture. The assembly has a corresponding structure to engage the engagement mechanism to absolutely fix the assembly onto the base plate. 
         [0008]    According to the present invention, an optical mouse includes a base plate having an engagement mechanism, and an optical module having a light source device, an optical sensor chip, an optical lens and the like optical components. The optical module has a corresponding structure to engage the engagement mechanism to absolutely fix the optical module onto the base plate. 
         [0009]    In an embodiment, the engagement mechanism includes a detent, a tenon, a slideway, a nut fixing post, a screw mount, a mounting tank, a mounting post or the like. The corresponding structure includes a groove, a concave hole, an opening, a flange plate, a support plate or the like. 
         [0010]    In one embodiment, the assembly or the optical module is adhered to the base plate by applying an adhesive. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    These and other objects, features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings, in which: 
           [0012]      FIG. 1  is an exploded view of a conventional optical mouse; 
           [0013]      FIG. 2  is a side view of the optical mouse shown in  FIG. 1 ; 
           [0014]      FIG. 3  is a schematic view illustrating how a conventional optical mouse is assembled; 
           [0015]      FIG. 4  is a schematic view illustrating how another conventional optical mouse is assembled; 
           [0016]      FIG. 5  is a schematic view of a first embodiment according to the present invention; 
           [0017]      FIG. 6  is a schematic view of a second embodiment according to the present invention; 
           [0018]      FIG. 7  is a schematic view of a third embodiment according to the present invention; 
           [0019]      FIG. 8  is a schematic view of a fourth embodiment according to the present invention; 
           [0020]      FIG. 9  is a schematic view of a fifth embodiment according to the present invention; 
           [0021]      FIG. 10  is a schematic view of a sixth embodiment according to the present invention; 
           [0022]      FIG. 11  is a schematic view of a seventh embodiment according to the present invention; 
           [0023]      FIG. 12  is a schematic view of an eighth embodiment according to the present invention; 
           [0024]      FIG. 13  is a schematic view of a ninth embodiment according to the present invention; 
           [0025]      FIG. 14  is a schematic view of a tenth embodiment according to the present invention; 
           [0026]      FIG. 15  is a schematic view of an eleventh embodiment according to the present invention; 
           [0027]      FIG. 16  is a schematic view of a twelfth embodiment according to the present invention; 
           [0028]      FIG. 17  is a schematic view of a thirteenth embodiment according to the present invention; 
           [0029]      FIG. 18  is a schematic view of a fourteenth embodiment according to the present invention; 
           [0030]      FIG. 19  is a schematic view of a fifteenth embodiment according to the present invention; 
           [0031]      FIG. 20  is a schematic view of a sixteenth embodiment according to the present invention; 
           [0032]      FIG. 21  is a schematic view of a seventeenth embodiment according to the present invention; 
           [0033]      FIG. 22  is a schematic view of an eighteenth embodiment according to the present invention; 
           [0034]      FIG. 23  is a schematic view of a nineteenth embodiment according to the present invention; 
           [0035]      FIG. 24  is a schematic view of a twentieth embodiment according to the present invention; 
           [0036]      FIG. 25  is a schematic view of a twenty-first embodiment according to the present invention; 
           [0037]      FIG. 26  is a schematic view of a twenty-second embodiment according to the present invention; 
           [0038]      FIG. 27  is a schematic view of a twenty-third embodiment according to the present invention; 
           [0039]      FIG. 28  is a schematic view of a twenty-fourth embodiment according to the present invention; 
           [0040]      FIG. 29  is a schematic view of a twenty-fifth embodiment according to the present invention; and 
           [0041]      FIG. 30  is a schematic view of a twenty-sixth embodiment according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0042]      FIG. 5  is a schematic view of a first embodiment according to the present invention, in which after an optical sensor chip  50  and a light source device  54  are soldered onto a PCB  52 , the PCB  52  is assembled with an optical lens  58  by means of a fixture  56  to form an assembly. A base plate  60  has a pair of detents  601  thereon, and the optical lens  58  has grooves  581  corresponding to the detents  601 . During assembly, the detents  601  engage with the grooves  581  respectively so that the base plate  60  and the assembly including the optical lens  58 , the PCB  52  and the fixture  56  are absolutely fixed together. 
         [0043]      FIG. 6  is a schematic view of a second embodiment according to the present invention, in which a base plate  60  has two tenons  602 , and an optical lens  58  has grooves  582  corresponding to the tenons  602 . During assembly, the grooves  582  in the assembly including the optical lens  58 , the PCB  52  and the like engage with the tenons  602  on the base plate  60  to absolutely fix the assembly and the base plate  60  together. 
         [0044]      FIG. 7  is a schematic view of a third embodiment according to the present invention, in which a PCB  52  having an optical sensor chip  50  and a light source device (not shown) soldered thereon is assembled with an optical lens  58  by means of a fixture  56  to form an assembly. The base plate  60  has a slideway  603  for outer edges of the optical lens  58  to slide therein, thereby absolutely fixing the assembly and the base plate  60  together. 
         [0045]      FIG. 8  is a schematic view of a fourth embodiment according to the present invention, in which a base plate  60  has nut fixing posts  604 , and an optical lens  58  has openings  583  for the nut fixing posts  604  to be inserted there through respectively. During assembly, nuts  605  are used to lock the optical lens  58  to the nut fixing posts  604  on the base plate  60 , thereby absolutely fixing the assembly and the base plate  60  together. 
         [0046]      FIG. 9  is a schematic view of a fifth embodiment according to the present invention, in which a base plate  60  has screw mounts  606  so that screws  607  are threaded through openings  583  of an optical lens  58  into the screw mounts  606  to absolutely fix the assembly and the base plate  60  together. 
         [0047]      FIG. 10  is a schematic view of a sixth embodiment according to the present invention, in which by using a dispenser  800  to dispense an adhesive on a surface beneath the optical lens  58 , the optical lens  58  is adhered to the base plate  60  to absolutely fix the assembly and the base plate  60  together. 
         [0048]      FIG. 11  is a schematic view of a seventh embodiment according to the present invention, in which grooves  521  are disposed on a PCB  52  for detents  601  on a base plate  60  to engage with. 
         [0049]      FIG. 12  is a schematic view of an eighth embodiment according to the present invention, in which a PCB  52  has concave holes  522  to engage with tenons  602  on a base plate  60 . 
         [0050]      FIG. 13  is a schematic view of a ninth embodiment according to the present invention, in which a base plate  60  has slideways  603  for outer edges of a PCB  52  to slide therein, thereby absolutely fixing the assembly and the base plate  60  together. 
         [0051]      FIG. 14  is a schematic view of a tenth embodiment according to the present invention, in which a PCB  52  has openings  523  so that nuts  605  can be inserted therein to lock the PCB  52  to nut fixing posts  604  on a base plate  60 , thereby absolutely fixing the assembly and the base plate  60  together. 
         [0052]      FIG. 15  is a schematic view of an eleventh embodiment according to the present invention, in which a base plate  60  has screw mounts  606  so that screws  607  are threaded through openings  523  into the screw mounts  606  to absolutely fix the assembly and the base plate  60  together. 
         [0053]      FIG. 16  is a schematic view of a twelfth embodiment according to the present invention, in which a PCB  52  is designed to be much wider, and by using a dispenser  800  to dispense an adhesive onto a base plate  60 , the PCB  52  is adhered to the base plate  60 , thereby absolutely fixing the assembly and the base plate  60  together. 
         [0054]      FIG. 17  is a schematic view of a thirteenth embodiment according to the present invention, in which two sides of a fixture  56  are extended beyond a support plates  560 , so that grooves  561  can be formed thereon to engage with detents  601  on a base plate  60  to absolutely fix the assembly and the base plate  60  together. 
         [0055]      FIG. 18  is a schematic view of a fourteenth embodiment according to the present invention, in which concave holes  562  are formed on support plates  560  extended outwards from both sides of a fixture  56  to engage with tenons  602  on a base plate  60 . 
         [0056]      FIG. 19  is a schematic view of a fifteenth embodiment according to the present invention, in which a fixture  56  has flange plates  563  extended outwards from both sides thereof to engage with slideways  603  on a base plate  60 , thereby absolutely fixing the assembly and the base plate  60  together. 
         [0057]      FIG. 20  is a schematic view of a sixteenth embodiment according to the present invention, in which support plates  560  at both sides of a fixture  56  have openings  564  respectively, so that nuts  605  can be locked to nut fixing posts  604  on a base plate  60  through the openings  564 , thereby absolutely fixing the assembly and the base plate  60  together. 
         [0058]      FIG. 21  is a schematic view of a seventeenth embodiment according to the present invention, in which a base plate  60  has screw mounts  606  so that screws  607  are locked through openings  564  of support plates  560  at both sides of a fixture  56  into the screw mounts  606  to absolutely fix the assembly and the base plate  60  together. 
         [0059]      FIG. 22  is a schematic view of an eighteenth embodiment according to the present invention, in which by using a dispenser  800  to dispense an adhesive onto a bottom surface of support plates  560  at both sides of a fixture  56  or a base plate  60  to form a layer of adhesive between the base plate  60  and the support plates  560 , the fixture  56  is adhered to the base plate  60 , thereby absolutely fixing the assembly and the base plate  60  together. 
         [0060]      FIG. 23  is a schematic view of a nineteenth embodiment according to the present invention, in which an optical module  70  includes a PCB, an optical sensor unit, a light source device, an optical lens and the like optical components. On an enclosure of the optical module  70  are formed grooves  701  corresponding to detents  721  so that when the optical module  70  and a base plate  72  are assembled together, the detents  721  engage with the grooves  701  to absolutely fix the optical module  70  to the base plate  72 . 
         [0061]      FIG. 24  is a schematic view of a twentieth embodiment according to the present invention, in which an optical module  70  has support plates  702  at both sides thereof, and the support plates  702  have concave holes  703 , respectively, to engage with tenons  723  on a base plate  72  to absolutely fix the optical module  70  to the base plate  72 . 
         [0062]      FIG. 25  is a schematic view of a twenty-first embodiment according to the present invention, in which an optical module  70  has flange plates  704  at both sides thereof for slideways  724  on a base plate  72  to slide therein and engage therewith, thereby absolutely fixing the optical module  70  and the base plate  72  together. 
         [0063]      FIG. 26  is a schematic view of a twenty-second embodiment according to the present invention, in which an optical module  70  has support plates  702  at both sides thereof, openings  705  in the support plates  702  encircle nut fixing posts  725  on a base plate  72 , and nuts  726  are locked to the nut locking post  725 , thereby absolutely fixing the optical module  70  and the base plate  72  together. 
         [0064]      FIG. 27  is a schematic view of a twenty-third embodiment according to the present invention, in which screws  728  are locked to screw mounts  727  through openings  705  in support plates  702  at both sides of an optical module  70 , thereby absolutely fixing the optical module  70  and a base plate  72  together. 
         [0065]      FIG. 28  is a schematic view of a twenty-fourth embodiment according to the present invention, in which a base plate  72  has a mounting tank  729  for mounting an optical module  70 , and the dimensions and profile of the mounting tank  729  are designed in such a way that the optical module  70  and the base plate  72  are absolutely fixed together. 
         [0066]      FIG. 29  is a schematic view of a twenty-fifth embodiment according to the present invention, in which a base plate  72  has four mounting posts  730  thereon to install an optical module  70 , thereby absolutely fixing the optical module  70  and the base plate  72  together. 
         [0067]      FIG. 30  is a schematic view of a twenty-sixth embodiment according to the present invention, in which by using a dispenser  800  to dispense an adhesive onto a base plate  72 , an optical module  70  is adhered to the base plate  72 . 
         [0068]    In addition to the fixation structure combination conventionally provided by recesses and fool-proof devices, an optical mouse according to the present invention further provides a mechanism for absolute fixation between an optical module or assembly and a base plate. In other embodiments, an optical module or assembly and a base plate may be joined together by various means so long as the optical module or assembly and the base plate are absolutely fixed together to ensure a correct light path of the optical mouse. 
         [0069]    While the present invention has been described in conjunction with preferred embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and scope thereof as set forth in the appended claims.