Patent Publication Number: US-9894263-B2

Title: Handheld magnifier camera with variable focus distance

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. application Ser. No. 14/593,600, filed on Jan. 9, 2015, entitled “Handheld Magnifier Camera with Variable Focus Distance,” now U.S. Pat. No. 9,451,156, issued Sep. 20, 2016, which claims priority to U.S. Application Ser. No. 61/925,949, filed Jan. 10, 2014, and entitled “Handheld Magnifier Camera with Variable Focal Length,” the contents of which are fully incorporated herein for all purposes. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates to a magnification device for individuals with low vision. More particularly, the present invention relates to a handheld magnification device with a variable focus distance. 
     Description of the Background Art 
     The use of electronic magnifiers for low vision users is known in the art. These magnifiers typically include an image sensor and a lens that are configured to provide enlarged images of an associated object. One issue with magnifier cameras is depth of field. Depth of field refers to the closest and farthest distances an object can be viewed while maintaining focus. Providing a large depth of field is desirable because it allows users to view objects at various distances without having to refocus the camera. However, depth of field is often lost as the resolution of the sensor is improved. Namely, as a camera&#39;s resolution increases, the depth of field decreases. In order to compensate for the loss of depth of field, the focus must be varied. For a lens having a fixed focal length, this can be accomplished by mechanically moving the lens. 
     What is needed, therefore, is a high resolution magnifier camera with a means for mechanically moving the associated lens. This would permit a higher resolution sensor to be employed without diminishing the perceived depth of field when using the magnifier. The portable multi position magnifier camera of the present invention is directed at fulfilling these needs. 
     SUMMARY OF THE INVENTION 
     It is therefore one of the objects of this invention to provide a magnifier camera with a variable focus distance. 
     Yet another advantage is realized by mechanically changing the focus distance of a lens to thereby provide a wider perceived depth of field. 
     Still another advantage is achieved by allowing higher resolution optical sensors to be used without sacrificing depth of field. 
     A further advantage is attained by mechanically changing the focus distance of a lens depending upon the configuration of a camera. 
     It is therefore one of the objectives of this invention to allow a user to configure a magnifier camera into one of a variety of viewing modes so as to optimize the viewing of different sized objects at differing distances. 
     It is another objective of this invention to provide a magnifier camera that can either be held in front of an object to be viewed or positioned upon the object to be viewed. 
     It is yet another objective of this invention to provide a magnifier camera that is hand-held, compact, and readily transportable. 
     The foregoing has outlined rather broadly the more pertinent and important features of the present invention in order that the detailed description of the invention that follows may be better understood so that the present contribution to the art can be more fully appreciated. 
     Additional features of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which: 
         FIG. 1  is front plan view of the magnifier of the present invention. 
         FIG. 2  is a back plan view of the magnifier of the present invention. 
         FIG. 3  is a perspective view of the front of the magnifying apparatus. 
         FIG. 4  is a perspective view of the back of the magnifying apparatus. 
         FIG. 5  is a side view illustrating the various orientations of the magnifying apparatus. 
         FIG. 6  is a view of the magnifying apparatus in its first orientation. 
         FIG. 7  is a view of the magnifying apparatus in its third orientation. 
         FIG. 8  is a view of the magnifying apparatus in its second orientation. 
         FIG. 9  is a cross sectional view showing the internal light chamber of the handle. 
         FIG. 10  is a side view of the magnifier illustrating the light being directed to a focal point beneath the housing. 
         FIG. 11  is a perspective and partially exploded view of the magnifier camera with the battery cover removed. 
         FIG. 12  is a perspective and partial exploded view of the variable focus assembly. 
         FIG. 13  is a perspective view of the variable focus assembly. 
         FIG. 14  is a side elevational view of the variable focus assembly. 
         FIGS. 15-17  are diagrams illustrating depth of field and variable focus. 
     
    
    
     Similar reference characters refer to similar parts throughout the several views of the drawings. 
     
       
         
           
               
             
               
                   
               
               
                 PARTS LIST 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 20 
                 Magnifier Device 
               
               
                 22 
                 Housing 
               
               
                 24 
                 Handle 
               
               
                 26 
                 Front Face (Housing) 
               
               
                 28 
                 Back Face (Housing) 
               
               
                 32 
                 Peripheral Edge (Housing) 
               
               
                 34 
                 Sensor 
               
               
                 36 
                 Aperture (Housing) 
               
               
                 38 
                 Screen 
               
               
                 42 
                 Power Button 
               
               
                 44 
                 Camera Button 
               
               
                 46a/46b 
                 Zoom Button 
               
               
                 48a/48b 
                 Mode Control Button 
               
               
                 52 
                 LEDs 
               
               
                 54 
                 Focal Point 
               
               
                 56 
                 Object Being Viewed 
               
               
                 58 
                 Front Face (Handle) 
               
               
                 62 
                 Back Face (Handle) 
               
               
                 64 
                 Peripheral Edge (Handle) 
               
               
                 66 
                 Aperture (Handle) 
               
               
                 68 
                 Light Guides (Handle) 
               
               
                 72 
                 Opening (Handle) 
               
               
                 74 
                 Battery Door 
               
               
                 76 
                 Batteries 
               
               
                 78 
                 Light Chamber 
               
               
                 82 
                 Angled Surfaces (Chamber) 
               
               
                 84 
                 Batter Compartments 
               
               
                 100 
                 Variable Focus Assembly 
               
               
                 110 
                 Circuit Board 
               
               
                 112 
                 Housing 
               
               
                 114 
                 Cavity 
               
               
                 116 
                 Cradle for Lens 
               
               
                 118 
                 Cradle Axle 
               
               
                 120 
                 Axle Slots in Housing 
               
               
                 122 
                 Sidewalls 
               
               
                 124 
                 Lens 
               
               
                 126 
                 Lens Cap 
               
               
                 128 
                 Clevis 
               
               
                 132 
                 Clevis Axle 
               
               
                 134 
                 Axle Mounts in Housing 
               
               
                 136 
                 Axle Mounts in Clevis 
               
               
                 138 
                 Actuator 
               
               
                 142 
                 Actuator Spring 
               
               
                 144 
                 Set Screw 
               
               
                 148 
                 Sensor 
               
               
                 “O” 
                 Object being Viewed 
               
               
                 “F” 
                 Focus distance 
               
               
                   
               
            
           
         
       
     
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention relates to a magnifier device for use by blind or low vision users. The magnifier includes a camera that can display enlarged images of target objects for viewing by the user. The magnifier device further includes a handle that is pivotally interconnected to a housing to thereby allow the device to be configured in a number of different configurations. The various features of the present invention, and the manner in which they interrelate, will be described in greater detail hereinafter. 
     With reference to  FIGS. 1-4 , the housing  22  and interconnected handle  24  of the magnifier  20  are illustrated. These components are preferably formed from an impact resistant plastic, such as an acrylonitrile butadiene styrene (ABS) plastic, or an equivalent thereof. Handle  24  and housing  22  are engaged with one another about an axis to thereby permit rotation of handle  24 . As noted more fully hereinafter, magnifier  20  takes on various configurations based upon the angle of handle  24 . 
     Housing  22  is defined by front and back faces ( 26  and  28 , respectively) and an associated peripheral edge  32 . With reference to  FIG. 2 , the camera for use with the magnifier is depicted. In the preferred embodiment, camera is a high definition CMOS sensor  34 . Such sensors are commercially available and those of ordinary skill in the art will appreciate suitable equivalents thereto. With continuing reference to  FIG. 2 , it is seen that the sensor  34  includes a lens aperture that is aligned with an aperture  36  on the back face  28  of housing  22 . The output from sensor  34  is supplied to an image processor. Additionally, images captured by sensor  34  can be stored in non-volatile memory to be recalled later by the user. The images can be processed by the imaging method described in commonly owned and co-pending application entitled “System and Method for Imaging Objects” (app. No. 61/099,185) filed on Sep. 22, 2008. The contents of this co-pending application are fully incorporated herein. 
     Stored images, or images currently viewed with sensor  34 , can be displayed on screen  38 . In the depicted embodiment, an LCD screen  38  is employed. Screen  38  is ideally recessed within front face  26  of housing  22 . As such, a peripheral edge  32  is inwardly beveled. The LCD screen  38  is a color display. Low-voltage differential signaling (LVDS) or parallel low voltage CMOS signaling can be used to interconnect the LCD screen  38  to the image processor as noted above. This arrangement ensures a purely digital output on LCD screen  38  and also permits magnifier  20  to be used with an external monitor (not shown). Thus, by way of the LCD screen  38 , objects within range of sensor  34  can be selectively displayed and digitally enlarged for the blind or low-vision user. 
     With reference to  FIG. 1 , the magnifier controls are illustrated. Controls are included for: power  42 , camera/sensor  44 , zoom  46 , and mode  48 . Power button  42  is used to turn the device  20  on and off. Camera button  44  is used to take “snap shots” of the object being viewed. Depressing the control the captures the images and stores it in memory for later viewing. Zoom button  46  is used to change the magnification employed by sensor  34 . For instance, by cycling zoom button  46 , the user can select a suitable magnification level. In the preferred embodiment, magnification between 5× to 15× are possible. Finally, mode control  48  can be used to change the color combinations displayed upon screen  38 . For instance, the screen can display objects in various color combinations, such as blue/green, red/yellow, or black/white. These color combinations can be cycled through until the user finds the mode effective output. 
     Light sources are also mounted to back face  28  of housing  22 . In the preferred embodiment, these light sources are light emitting diodes (LEDs)  52 . Other light sources can alternatively be used. With particular reference to  FIGS. 9 and 10 , it can be seen that LEDS  52  are preferably mounted at an angle relative to the plane of housing  22 . The depicted angle is approximately 45°. The back face  28  is raised about the LEDs  52  to thereby shield the LEDs  52  from damage. As illustrated, LEDs  52  are angled such that the emitted light emitting converges on a focal point  54 . Preferably, focal point  54  is located at or near the object being viewed  56 . LEDs  52  can be selectively illuminated depending upon ambient lighting conditions. 
     With reference again to  FIGS. 1-4 , handle  24  of the device  20  is described. Handle  24  is defined by a front face  58 , a back face  62 , and a peripheral edge  64  therebetween. An aperture  66  and a pair of light guides  68  are formed within back face  62 . Additionally, an opening  72  formed is within front face  58  and is positioned such that it is in alignment with aperture  66 . As noted in  FIG. 11 , handle  24  further includes a battery door  74 . The edges of battery door  74  are designed to slide into corresponding grooves within the peripheral edges  64  of handle  24 . Door  74  serves to enclose batteries  76  that are positioned within handle  24  and which power device  20 . In the depicted embodiment, four “AAA” batteries  76  are use. 
     Handle  24  also includes an internal light chamber  78 . Chamber  78  is most easily seen in the cross sectional view of  FIG. 9 . As described more fully hereinafter, light chamber  78  directs light from LEDs  52  to the object being viewed  56 . One suitable light chamber is described in commonly owned U.S. Pat. No. 7,172,304 to Rodriguez et. al., the contents of which are fully incorporated herein. Whatever type of light chamber is utilized, it should include angled surfaces that are lightly colored to promote maximum light reflection and diffusion. In the preferred embodiment, light chamber  78  is white and includes angled surfaces  82  that are positioned immediately below light guides  68 . With continuing reference to  FIG. 4 , it is seen that battery compartments  84  are positioned on either side of light chamber  78 . 
     By pivoting handle  24  with respect to housing  22 , magnifier  20  can be brought into a number of different orientations. The user can select the desired orientation for optimal viewing. The various magnifier orientations are described below in connection with  FIGS. 5-8 . 
     First Orientation 
     The first orientation of the magnifier  20  is depicted in  FIG. 1 . This orientation is defined by housing  22  and handle  24  being in alignment with one another. Namely, the angle between housing  22  and handle  24  is 180°, or approximately 180°. This orientation is preferred when magnifier  20  is used to view objects  56  at a distance or when the user otherwise does not need both hands free. In the orientation, the user holds magnifier  20  by grasping handle  24  and pointing sensor  34  at an object  56 . The user&#39;s free hand can then be used to operate the controls to, for example, zoom in on the object (button  46 ), or take a snap shot (button  44 ). In this orientation, objects are viewed through the bottom of housing  22 , while handle  24  is used to grasp the device  20 . 
     Second Orientation 
     The second orientation of the magnifier  20  is depicted in  FIG. 8 . Here, handle  24  and housing  22  are positioned at an angle of less than 180°. In the depicted embodiment, housing  22  is positioned at a 45° angle relative to handle  24 . When so configured, handle  24  can be positioned upon a surface, such as a table, and objects  56  can be placed in front of camera  34 . Magnifier  20  can maintain this position because handle  24  is substantially heavier than housing  22  insomuch as handle  24  houses batteries. By positioning the device  20  on a table, the user is free to use both hands, as may be preferred if the object  56  needs to be manipulated in front of camera sensor  34 . Thereafter, the user can utilize the controls to zoom in (button  46 ) and capture desired images (camera button  44 ). 
     Third Orientation 
       FIG. 7  illustrates the third orientation. Here, the back faces ( 28 ,  62 ) of the housing and handle ( 22 ,  24 ) are brought together, such that they are in facing relation to one another. In other words, the angle between housing  22  and handle  24  is 0°, or approximately 0°. This orientation is preferred when magnifier  20  is to be positioned directly over an object  56 . This includes resting magnifier  20  directly upon a flat object  56  such as a document. In this configuration, sensor  34  is viewing the object through the aperture  36  in housing  22 , as well as aperture and opening ( 66 ,  72 ) in handle  24 . Furthermore, in the third orientation, the LEDs  52  are brought into registry with light guides  68  in handle  24 . Thus, LEDs  52  direct light through light guides  68 , into light chamber  78 , and out through opening  72 . In this manner, LEDs  52  can effectively illuminate the object being viewed  56 . 
     Variable Focus Assembly 
     The variable focus assembly  100  is next described in connection with  FIGS. 12-17 . As illustrated, assembly  100  is mounted upon a circuit board  110  within the interior of housing  22 . A lens housing  112 , with a cavity  114 , is mounted upon circuit board  110 . Cavity  114  is dimensioned to receive a lens cradle  116 . Cradle  116  includes opposing axles  118  that move within slots  120  formed within housing  112 . This arrangement allows lens cradle  116  to pivot about axles  118  in a manner more fully described hereinafter. Housing  112  includes opposing sidewalls  122  that restrain the pivotal movement of cradle  116  as it moves up and down. 
     Optical lens  124  is positioned within lens cradle  116 . Optical lens  124  is in registration with aperture  66 . A lens cap  126  is preferably secured over the lens  124  to both protect and prevent removal of lens  124 . The movement of both lens  124  and lens cradle  116  is achieved via a pivotal clevis  128 . Clevis  128  has rearward and forward ends ( 128   a  and  128   b ). Forward end  128   b  of clevis  128  has two opposing arms that are pivotally connected to the axles  118  of cradle  116 . The rearward end  128   a  of clevis  128  includes a threaded opening. Clevis  128  is pivotally mounted within housing  112  about an axis “A.” This is accomplished by a clevis axle  132  that is secured within axle mounts  136  within clevis  128  and axle mounts  134  within housing  112 . 
     The pivotal movement of clevis  128  is achieved via an actuator  138 . Actuator  138  is biased upwardly via an actuator spring  142 . Spring  142  is configured such that clevis  128  is biased to position cradle  118  and lens  124  in a seated position within cavity  114 . However, depressing actuator  138  overcomes the bias of spring  142  to move rearward end  128   a  of clevis  128  downwardly and the forward end  128   b  upwardly. Lens  124  and cradle  116  move upwardly along with forward end  128   b.  A set screw  144  is threadably received within the rearward end  128   a  of clevis  128 . Set screw  144  extends through the threaded opening in rearward end  128   a.  Screw  144  can be adjustably positioned to limit the pivotal movement of the clevis  128 . Driving screw  144  further into opening lessens the degree of pivotal movement by clevis  128 . A sensor  148  is positioned within housing  112  and in optical registry with lens  124 . This may be a high definition CMOS sensor. Actuator  138  can be depressed to move lens  124  closer to the object being viewed. This also has the desired effect of increasing the focus distance “F,” which is the distance between lens  124  and sensor  148 . 
     Actuator  138  is positioned and configured to be depressed by back face  62  of handle  24 . Namely, as device  20  is brought into the third orientation (note  FIG. 7 ), back face  62  contacts and depresses actuator  138 . As actuator  138  is depressed, clevis  128  is pivoted about axis “A.” This, in turn, moves lens  124  and lens cradle  118  closer to the object “O” being viewed. It also increases the focus distance “F” by increasing the distance between lens  124  and sensor  148 . This is the preferred optical configuration for viewing closely positioned objects. This movement occurs with the face of lens  124  staying parallel to the face of sensor  148 . Namely, as lens  124  moves upwardly, sidewalls  122  ensure that lens  124  does not pivot with respect to sensor  148  or object “O.” Nonetheless, axles  118  permit cradle  116  to pivot with respect to clevis  128 . Thereafter, once handle  24  is pivoted to the first or second orientations ( FIG. 6  or FIG.  8 ), actuator  138  is released and lens  124  and cradle  116  take a seated position within cavity  114 . This decreases the focus distance “F.” This is the preferred optical configuration for viewing more distant objects. 
     Although the present invention discloses a purely mechanical system for varying the focus distance “F,” it can also be carried out electrically or via an electro-mechanical system. Namely, a microprocessor can be included to determine the focus of the object “O.” Based upon the output of the microprocessor, lens  124  can be moved a corresponding distance to maintain focus. 
     With reference to  FIG. 15 , it can be seen that the focus distance “F” is the distance between lens  124  and associated sensor  148 . In order for object “O” to be in focus, light from lens  124  must converge at a point source upon sensor  148 . As noted in  FIG. 16 , given the same focus distance “F” a closer object “O” will be out of focus. In other words, the light from lens  124  no longer converges at sensor, but instead is truncated to form a larger circle upon sensor  148 .  FIG. 17  shows that object “O” can be brought back into focus by moving lens  124  closer to object “O” and further away from sensor  148 , thereby increasing focus distance “F.” By mechanically increasing focus distance “F,” a greater perceived depth of field can be achieved. Moreover, this perceived increase in depth of field can be achieved while still utilizing a lens  124  that has a fixed focal length. 
     The present disclosure includes that contained in the appended claims, as well as that of the foregoing description. Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention.