Abstract:
A viewfinder for attaching to a device having image-capturing capability has a structure for supporting an eyepiece, an engagement interface implemented on the structure to engage a complementary portion of a device having image-capture capability in a specific direction, and at least one eyepiece attached to the structure, such that the eyepiece has an axis proceeding in the specific direction with the viewfinder engaged to the device having image-capture capability.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present patent application is a continuation of pending application Ser. No. 13/413,221, filed on Mar. 6, 2012, entitled, “Detachable Viewfinder”, disclosure of which is incorporated herein in its entirety by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is in the technical field of image-capturing devices, such as cameras, and pertains more particularly to detachable viewfinders for such devices. 
     2. Description of Related Art 
     Since the advent of digital imaging, image-capture ability has been added to more and more devices. At the time of filing this patent application there is a very broad selection of commercially-available digital cameras, and most cellular telephones have digital image-capture ability. In the case of many digital cameras and cell phones, one may refer to the digital display to see what the camera will capture as a still or as video frames if the camera function is activated, typically by operating a button switch. The digital display, however is sometimes a bit clumsy to see while training the camera lens on a scene to capture, and in the case of bright sunlight, for example, may be difficult to see. Many devices have a viewfinder, but there are many that do not, in particular a lot of cellular telephones that include a digital camera. What is clearly needed is a detachable viewfinder for such devices, that may be added at times of need, and may be detached when not needed. 
     BRIEF SUMMARY OF THE INVENTION 
     In one embodiment of the present invention a viewfinder for attaching to a device having image-capturing capability is provided, comprising a structure for supporting an eyepiece, an engagement interface implemented on the structure to engage a complementary portion of a device having image-capture capability in a specific direction, and at least one eyepiece attached to the structure, such that the eyepiece has an axis proceeding in the specific direction with the viewfinder engaged to the device having image-capture capability. 
     In one embodiment the eyepiece is a linear element having a length and an opening having an axis through the length. Also in one embodiment the eyepiece is a cylinder. In another embodiment the structure has a linear portion with a central slot through which a threaded fastener may pass to engage a threaded hole in a camera body, and the eyepiece is attached to one end of the linear portion, the slot allowing the eyepiece to be positioned at variable distance from the camera body. 
     In an alternative embodiment the structure has a linear portion with a central slot through which a threaded fastener may pass to engage a threaded hole in a camera body, and the eyepiece is attached to an end of an extension proceeding at a right angle from one end of the linear portion, the slot allowing the eyepiece to be positioned at variable distance from the camera body. 
     In another alternative embodiment the structure for supporting an eyepiece comprises a linear portion having a base and sidewalls forming a groove, the sidewalls angled inward from the base to provide a gripping effect when engaging a planar portion of a device. In some cases the structure for supporting an eyepiece has more than one linear portion having a base and sidewalls forming a groove, the linear portions joined at angles such that the grooved structure may envelop a portion of the planar portion of a device. There may also be a gripping mechanism associated with the groove, for applying pressure to the planar portion when engaged. 
     In another aspect of the invention a method for adding a viewfinder to a device having image-capturing capability is provided, comprising the steps of (a) forming a structure for supporting an eyepiece; (b) implementing an engagement interface on the structure to engage a complementary portion of the device; and (c) attaching at least one eyepiece to the structure, such that the eyepiece has an axis proceeding in the specific direction with the viewfinder engaged to the device having image-capture capability. 
     In one embodiment of the method the eyepiece is a linear element having a length and an opening having an axis through the length. Also in one embodiment the eyepiece is a cylinder. 
     In one embodiment the structure has a linear portion with a central slot through which a threaded fastener may pass to engage a threaded hole in a camera body, and the eyepiece is attached to one end of the linear portion, the slot allowing the eyepiece to be positioned at variable distance from the camera body. In another embodiment the structure has a linear portion with a central slot through which a threaded fastener may pass to engage a threaded hole in a camera body, and the eyepiece is attached to an end of an extension proceeding at a right angle from one end of the linear portion, the slot allowing the eyepiece to be positioned at variable distance from the camera body. 
     In yet another alternative the structure for supporting an eyepiece comprises a linear portion having a base and sidewalls forming a groove, the sidewalls angled inward from the base to provide a gripping effect when engaging a planar portion of a device. Further there may be more than one linear portion having a base and sidewalls forming a groove, the linear portions joined at angles such that the grooved structure may envelop a portion of the planar portion of a device. In some cases a gripping mechanism associated with the groove, for applying pressure to the planar portion when engaged. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a perspective view of a digital camera with a detachable viewfinder according to one embodiment of the present invention. 
         FIG. 2  is a perspective view of a digital camera with a detachable viewfinder according to another embodiment of the present invention. 
         FIG. 3   a  is a perspective view of a folding, or “flip” phone with a detachable viewfinder in an embodiment of the present invention. 
         FIG. 3   b  shows the phone and viewfinder of  FIG. 3   a  fully engaged. 
         FIG. 3   c  is a cross-section through a portion of the structure of the viewfinder in  FIG. 3   a.    
         FIG. 4  illustrates another viewfinder in an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a perspective view of a digital camera  100  with a detachable viewfinder  101  according to one embodiment of the present invention. Camera  100  in this example is directed for image capture in the direction of arrow  108 , and has a button  103  for activating capture of a still image or for initiating frame capture for video. A smaller button  104  is for extending a lens mechanism, not shown as it is on the opposite side of the camera. There is in addition a button set  109  for zooming in or out with the lens mechanism. A button set  105  is for moving a cursor in a digital display  102  or for moving left, right, up or down among menu selections. 
     Detachable viewfinder  101  in this example has a long body  110  with a lengthwise slot  106  for engaging camera  100  by a threaded hole in the bottom of the camera (not shown) which is provided in the camera for attaching the camera to a tripod assembly. A thumb screw passes from below through slot  106  and is threaded into the threaded hole in the bottom of the camera. 
     A cylindrical eyepiece  107  is attached to body  106  at one end such that the axis of the cylinder is generally in the direction of arrow  108 . This attachment may be by welding or soldering, for example, or by other conventional means. In some cases the angle of the cylinder of the cylinder of the eyepiece may be angled slightly vertically and horizontally to account for parallax so that the eyepiece cylinder and the camera lens may intersect at a desired distance. In some cases the cylindrical eyepiece may be adjustable in angle over a small rotational range so parallax may be adjusted as well. 
     In some embodiments the cylindrical eyepiece may be attached at the end of body  110  opposite to that shown in  FIG. 1 . In some other embodiments there may be a cylindrical eyepiece attached at both ends of the body, and the user may choose which eyepiece to use. 
     It will be apparent to the skilled person that the representation of a digital camera in  FIG. 1  is exemplary only, and is meant to represent a range of different devices, many of which will have features different than those shown in this example. The camera represented is meant to represent any such camera or other image capturing device that has a threaded hole in the base for attaching to a tripod, as is common among such devices. The device need not be digital. 
     It will also be apparent to the skilled person that the length of body  110  and of slot  106  may vary considerably in different versions of a detachable viewfinder, allowing the cylindrical eyepiece to be set at varying distances from the camera to which it joined. Further cylindrical eyepiece  107  may vary in outside and inside diameter, and in length. In some cases the eyepiece is a simple mechanical cylinder, but in other cases there may be lenses in the cylinder. In other cases the eyepiece may be other than cylindrical, such as square or rectangular in cross-section. There are many possibilities. 
       FIG. 2  is a perspective view of a digital camera  100  with a detachable viewfinder  201  according to another embodiment of the present invention. Camera  100  is the same as in  FIG. 1 , and is meant to represent any image-capturing device that has a threaded hole in the base for attaching to a tripod. 
     Detachable viewfinder  201  has an extended base  202  with a lengthwise slot  204  for engaging camera  100 . A second extension  203  proceeds at substantially a right angle to base  202  in this example, and a cylindrical eyepiece  205  is attached at an upper end of extension  203 . The right-angle extension allows eyepiece  205  to present at a different aspect relative to the lens mechanism (not shown) of camera  100 , and to afford a different geometry for a user. As described with reference to  FIG. 1 , the eyepiece may have other shape than the cylinder shown, and may be mechanical, or may have lenses. The height of extension  203  may differ in different embodiments, and the angle of extension  203  with base  202  may be other than ninety degrees. The length of base  202  and slot  204  may be different in different embodiments, such that the eyepiece might be immediately adjacent the camera, or at some distance from the camera. As before, the angle of attachment of the eyepiece to extension  203  may vary to adjust for parallax. In some cases extension  203  and base  202  may be joined by fasteners, and therefore detachable as well, and the eyepiece might be joined to either upward extension  203 , or to base  202 . In some cases there may be an upward extension  203  at either end, or both ends, of base  202 , and there may be two eyepieces. 
       FIG. 3   a  is a perspective view of a folding, or “flip” phone  301 , with a detachable viewfinder  307  in an embodiment of the present invention. The detachable viewfinder in this example is shown detached above the flip phone, with an arrow showing the direction of engagement.  FIG. 3B  shows phone  301  with the viewfinder fully engaged. 
     Referring back to  FIG. 3   a , phone  301  has a base  302  with an I/O keypad  303  as is known in the art, and a folding portion  304  having a display  305  as is also known in the art. Viewfinder  307  in this embodiment has a U-shaped structure  309  formed in a manner to engage the upper part of folding portion  304  of phone  301 .  FIG. 3   c  is a cross-section through structure  309  taken along line  3   c - 3   c  in  FIG. 3   a . In one embodiment the side panels of the groove are angled slightly inward as shown, such that d 1  in  FIG. 3  is d 1  in  FIG. 3   a , that is, the thickness of folding portion  304 ; but d 2  in  FIG. 3  is somewhat less than d 1  due to the slight inwardly angled sidewalls of the groove. 
     In many embodiments folding portion  304  is molded of a plastic material that is flexible when finished, such that, as viewfinder  307  engages folding portion  304  the sidewalls that are separated at the dimension d 2  expand to d 1  so that the engagement may take place, and the flexing of the material provides a force against the opposite surfaces of folding portion  304  to hold the viewfinder in place once engaged. 
     Viewfinder  307  has an eyepiece  308  attached at a convenient location as shown in  FIG. 3   a , such that with the viewfinder engaged to the folding portion the eyepiece is convenient for the user to see the field that will be captured when the camera is triggered to capture an image. As described above, eyepiece  308  may be joined to structure  309  at an angle to account for parallax. Further, in some embodiments the eyepiece may be adjustable for this angle if needed, and in some embodiments the eyepiece may be moved from one location to another on structure  307 . Further, there may be more than one eyepiece, and the eyepiece need not be cylindrical as shown, but may have other shape, and in some cases may have a lens or lenses as well. 
     Further to the above, in some cases upper portion  304  of phone  301  may have one or more buttons or connectors in the edge region that might be covered when the viewfinder is engaged. In some cases structure  307  may be molded to provide openings for such connectors or buttons. In some cases one viewfinder may serve for two or more telephones, but some telephones may require a dedicated detachable viewfinder, which may be bundled with the phone when sold, or purchased separately. 
     It will be apparent to the skilled person that viewfinder  307  may engage telephones and/or other devices including image-capture mechanisms and systems, other than flip-phones as shown. It will further be apparent that the same principles may be used to provide a viewfinder with an eyepiece attached to a single straight piece of molded material, such as is shown in  FIG. 4 , which illustrates a viewfinder  400  according to an embodiment of the invention, having a straight grooved portion  401  and an attached eyepiece  402 . This embodiment is more universally adaptable to various existing commercial devices that have image-capture capability, because only one edge of such a device need be engaged. In this version as in others, the eyepiece may be cylindrical, as shown, or may have other shape or have lenses. 
     In one version of the detachable viewfinder  400 , the width at the bottom of the groove is made rather large, and the angle of one or both sidewalls inward is made rather more acute than as shown in  FIG. 3   c , so the one viewfinder might be used an a variety of devices of varying thickness. Further still, the length of portion  401  may be rather short, such as 0.5 inches, so there is a greater freedom of placement along the edge of a device to which the viewfinder may be engaged. 
     It will be apparent to the skilled artisan that the viewfinders taught in the disclosure above and the several figures provided may be manufactured of a variety of materials, and may be made in a variety of geometries as well, without departing from the spirit and scope of the invention. Further, the attachment mechanisms taught may have broader implementation as well. For example, referring to  FIG. 4 , rather than have angled sidewalls that may be flexed, a straight grooved portion may be provided with a spring-loaded mechanism to grip the thickness of a device having image-capture capability. In some embodiments there may be additional material added at the surfaces where a mechanism impinges on the surface of a telephone or other device. Such material, for example, may be such as to prevent marking or marring the surface of the device, or may be to enhance the gripping capability. Material may also be added for aiding the grip of the person using the device with the detachable viewfinder. There are many possibilities.