Abstract:
A lens carrier for operative engagement of a camera lens with an image sensor such as a Charge Coupled Device or CMOS device. The lens mounts in a lens barrel on the lens carrier and may be laterally translated along the lens barrel to focus the image projected by the lens on an adjacent image sensor. The lens carrier also provides for self centering of the center axis of the lens with the center point on the imaging surface of the image sensor and for a perpendicular alignment of the lens center axis with the imaging surface to achieve the best conversion of the visual image from the lens into analog or digital format for use by electric devices.

Description:
FIELD OF THE INVENTION 
     The disclosed device relates to digital cameras. More particularly, it relates to a device to provide cooperative operative engagement of the lens of a digital camera with the computer chip which digitizes the image communicated from the lens. 
     BACKGROUND OF THE INVENTION 
     Conventional photography and film use a lens which focuses the light received through the lens on film which chemically reacts to the light and chemicals used later to produce an image on the film. That image can be converted to a photograph using conventional photo printing methods and the camera produced film negative. The key difference between a digital camera and a film-based camera is that the digital camera has no film. Instead, it has an electronic image sensor that converts light projected upon the image sensor into electrical charges. The ability to produce electronic or printed pictures from photos stored on digital cameras is a direct result of this shift from recording an image on film to recording the image in digital form using the image sensor to take the projected image from a conventional lens and convert it to computer useable format. 
     The image sensor employed by most digital cameras is a charge coupled device (CCD). Some low-end cameras use complementary metal oxide semiconductor (CMOS) technology. However, the majority of digital cameras employ a CCD as the image sensor to convert the visible image from the lens to a digitized electronic image that may be stored in a computer memory and printed in a variety of fashions. 
     The CCD is a collection of tiny light-sensitive diodes, which convert photons (light) into electrons (electrical charge). These diodes are called photosites. Each photosite is sensitive to light focused on the CCD surface by the lens and the brighter the light that hits a single photosite, the greater the electrical charge that will accumulate at that site on the photosite on the CCD surface. Consequently, a digital camera is similar to a film camera except that the film is replaced with an electronic image sensor in the form of the CCD. 
     The electrons produced by the light that hits the individual photosites on the CCD are stored in small capacitors which are read out as a series of voltages which are proportional to the image brightness. This series of rising and falling voltages is then converted to a number by an analog to digital converter and the series numbers are stored and processed by a computer within the camera or communicating with the camera to form the digital or electronic image. 
     In many designs, a mechanical shutter in the lens field of view is used in the same way that it is used in a film camera—to gate the light that is allowed to reach the CCD. Other cameras use what is called an electronic shutter which allows the control of when the CCD gathers light through electronic control of signals to and from the CCD. 
     As such, the quality of the light focused by the lens, on the image sensor, whether it be a CCD or CMOS, is of utmost importance to the eventual quality of the digital image produced by the image sensor and stored on the computer or in the camera. It is thus imperative that the light communicated through the lens reach the image sensor at substantially the center point and that the lens axis be substantially perpendicular to the imaging surface of the image sensor. An angle in the lens axis in relation to the image sensing surface will produce unfocused images with one half of the image in focus and the other out of focus. Also, if the center axis of the lens does not substantially line up with the center point of the image sensing surface, the resulting digital image transmitted by the image sensor will be off center, have darker corners or edge portions, and of inferior quality. 
     Currently, lenses used on digital cameras are placed in lens holders that mate to positions on a circuit board which also mounts the image sensor. The conventional lens holders are affixed in communication with the circuit board using fasteners such as screws and during this fastening process a centering of the lens axis over the center point of the imaging surface of the image sensor is either not controlled, attempted by hand, or estimated using the screw mounting to the circuit board. Unfortunately, due to the tolerances in the mounting of the image sensor and the plurality of planes it can fall into in its attachment to the circuit board, combined with the additional tolerances of mounting the lens holder to a physical mounting on the circuit board around or adjacent to the image sensor and at potentially different planes, it is extremely hard to place the center axis of the lensholder-mounted lens, centered on the center point of the imaging surface and also perpendicular to that surface. Consequently, much hand adjustment by persons mounting the lens to the board is required and many assembled components fail to produce an adequate digital image due to misalignment caused by the multiple tolerances in lens attachment to the board and image sensor attachment to the same circuit board. 
     As such, there is a pressing need for a device which will cooperatively engage the lens used with a digital camera and operatively mount that lens with its center axis lined up with the center point of the imaging surface on the image sensor. Such a device should also maintain the lens center axis substantially perpendicular to the imaging surface of the image sensor and also provide a means to adjust the distance between the projection end of the lens and that imaging surface for focus of the projected image on the imaging surface. Still further, such a device should allow for easy attachment of the lens to the image sensor instead of the circuit board with little or no need for adjustment during manufacture. 
     SUMMARY OF THE INVENTION 
     The above problems, and others are overcome by the herein disclosed and described lens carrier for cooperative operative engagement with the image sensor such as a CCD or CMOS device, or a chip carrier holding the image sensor to a circuit board surface. 
     The camera lens carrier herein described and disclosed features a base having a barrel having an axial channel therethrough attached to the base and communicating therethrough. The lens barrel is configured to cooperatively engage the exterior of a camera lens. The cooperative engagement allows for a threaded or other laterally translatable adjustment of the distance inside the barrel in which the lens protrudes and therefor the distance that the projection end of the lens is mounted above the base. 
     The center axis of the barrel is also positioned to line up substantially with the center point on the imaging surface of the image sensor to be used in combination herewith. Consequently, the image projected by the lens is centered on the imaging surface once the lens carrier is cooperatively engaged with the image sensor or the chip carrier holding the image sensor used in combination herewith. 
     The bottom surface of the base is configured for cooperative engagement with the edge of the image sensor used to capture the lens-projected image. This edge in generally substantially parallel to the imaging surface of the image sensor itself and therefor a cooperative engagement with the edge will yield a parallel engagement of the base with the imaging surface. Since the base is perpendicular to the lens barrel, the lens when cooperatively engaged in the lens barrel with the base cooperatively engaged with the edge of the image sensor will place the lens center axis lined up with the center point of the imaging surface and perpendicular to the imaging surface to yield optimum optical clarity. This cooperative engagement of the base of the lens carrier thereby yields a means for perpendicular alignment of the lens axis with the imaging surface of the image sensor. 
     A means to focus the image projected by the lens on the imaging surface is provided by the cooperative laterally adjustable engagement of the lens barrel with the lens and the ability of that cooperative engagement to adjust the distance between the projection end of the lens and that imaging surface thereby providing easy attachment of the lens to the image sensor instead of the circuit board with little or no need for adjustment during manufacture. 
     Accordingly, it is the object of this invention claimed herein to provide a simplified means of attachment of optical lenses to electronic image sensors such as CCD&#39;s and CMOS devices. 
     It is another object of this invention to provide such a means of attachment of the optical lens which also centers the axis of the lens to the center point of the imaging surface of the image sensor. 
     It is still another object of this invention to provide a component for attachment of lenses to electronic image sensors that cooperatively engage with the image sensor thereby alleviating the need for screws and adhesives. 
     It is a still further object of this invention to provide such a lens attachment to image sensors that aligns the center axis of the lens perpendicular to the plane of the imaging surface of the image sensor. 
     It is yet another object of this invention to provide such a component for attaching a lens to an electronic image sensor which provides a means to easily focus the image projected by the lens on the image sensor imaging surface. 
     Further objectives of this invention will be brought out in the following part of the specification, wherein detailed description is for the purpose of fully disclosing the invention without placing limitations thereon. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     The accompanying drawings which are incorporated in and form a part of this specification illustrate embodiments of the disclosed processing system and together with the description, serve to explain the principles of the invention. 
     FIG. 1 depicts a side view of the lens carrier operatively mounted in cooperative registered engagement with the electronic image sensor mounted on a conventional circuit board. 
     FIG. 2 depicts a top view of a conventional Charge Coupled Device that is used to convert images projected from a lens to digital format. 
     FIG. 3 depicts a side cut away view of disclosed lens carrier in another favored embodiment wherein operative engagement of the lens carrier with the imaging sensor is achieved by cooperative mating fasteners formed in the lens carrier and a chip carrier holding the image sensor to a circuit board. 
     FIG. 4 depicts the underside of a preferred embodiment of the lens carrier showing stepped edges for registered engagement with a side edge of a chip carrier or the image sensor showing a plurality of biased clips for engagement therewith. 
     FIG. 5 depicts a section through FIG. 4 showing the cooperative engagement of the biased clips with the side edge of the chip carrier and resulting biased self centering of the lens over the center of the chip carrier. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to FIG. 1 depicts a side view of the disclosed device  10  showing the lens carrier  12  operatively mounted to an image sensor  14  such as a charge coupled device or CMOS device used to convert projected images from a lens  16  to be communicated in analog or digital format to a computer or electronic camera or similar device for displaying digital pictures. 
     Currently, the image sensor  14  is mounted in a conventional chip carrier  18  designed to engage such image sensors  14  on a circuit board  20 . Generally the perimeter of the image sensor  14  has electrical contacts which engage with mating electrical contacts on the chip carrier  18  which is operatively attached to the circuits of the circuit board. The chip carrier  18  has a substantially flat ledge  22  about the perimeter of a top surface  24  of the chip carrier  18  and a detent inside the ledge  22  where the image sensor  14  is engaged. The image sensor  14  conventionally has a planar imaging surface  28  on which the picture projected by the lens  16  is projected. It is highly desirable that the lens center axis which is substantially the same as the barrel center axis  30  substantially line up with the center point  26  of the imaging surface  28  so that the image from the lens properly registers in the imaging surface  28  for electronic transmission to the electronic device attached. Any misalignment will cause the resulting digital picture to be inferior and off center. It is also highly desirable to align the barrel center axis  30  substantially perpendicular to the surface of the imaging surface  28  to yield optimum picture quality. 
     A lens barrel  32  is attached perpendicular to the base  34  and has an axial passage  36  running the length of the lens barrel  32  and communicating through the base  34 . Operative engagement of the lens  16  with the lens barrel  32  is best achieved using a system of cooperative engagement that provides for SAID PRODUCTS translation of the lens  16  in the barrel. Such SAID PRODUCTS translation provides a means to focus the image projected on the imaging surface  28  by the lens  16  by moving the projection end toward or away from the imaging surface  28 . In the current best mode threads  38  on the circumference of the lens  16  engage with threads on the interior wall  40  of the lens barrel  32 . Twisting the lens  16  will as such, screw it toward or away from the imaging surface  28  when the lens carrier  12  is operatively engaged with the image sensor  14 . While mating threads are the current best mode, other means of lateral or axial translation of the lens  16  in the lens barrel  32  could be used such as a lens barrel  32  that is slotted and matching notch on the lens  16  or simply frictional engagement of the exterior of the lens  16  with the interior wall  40  of the lens barrel  32  and such other means of SAID PRODUCTS translation are anticipated. 
     The lens carrier  12  is designed to engage the lens  16  in the lens barrel  32  and project the image from the lens  16  onto the operatively attached image sensor  14 . As noted above, the barrel center axis  30  should optimally line up with the center point  26  of the imaging surface  28  and concurrently be perpendicular thereto. A means of alignment of the barrel center axis  30  with the center point  26  is provided by a recess  42  formed in the bottom surface  44  of the base  34 . The recess  42  is cut into the bottom surface  44  and is positioned and dimensioned to cooperatively engage the perimeter edge of the chip carrier  18  holding the image sensor  14  or the perimeter of the image sensor  14  itself should it not have a chip carrier  18 , and, to register the barrel center axis  30  directly over the center point  26  of the imaging surface  28 . This embodiment of a means of alignment of the barrel center axis  30  with the center point  26  works best if the chip carrier  18  is manufactured with a shaped perimeter edge or shoulder designed to cooperatively engage the recess  42  in the bottom surface  44  of the lens carrier  12 . Consequently this matched set of a chip carrier  18  and lens carrier  12  designed to cooperatively engage and center the barrel center axis  30  over the center point  26  is anticipated. 
     Using either means of alignment of the barrel center axis with the center point  26  the image projected from the lens  16  which communicates through the lens barrel  32  and through the base  34  is substantially centered on the imaging surface  28  of the image sensor  14  by simply placing the recess  42  formed in the lens carrier  12  in over the chip carrier  18  or image sensor  14  if no chip carrier is used, engaging the two. The recess  42  will encircle a cooperatively shaped perimeter of the chip carrier  18  or image sensor  14  and hold the barrel center axis  30  centered. 
     A means for perpendicular alignment of the barrel center axis  30  with the imaging surface  28  of the image sensor  14  is provided by engagement of the recess  42  with a top surface of the chip carrier  18  or the image sensor  14 . The top wall  45  is cut substantially flat and perpendicular to the barrel center axis  30  and consequently the lens center axis when the lens  16  cooperatively engaged in the lens barrel  32 . In this fashion, when the recess  42  is placed over the image sensor  14 , the flat ledge  22  on the chip carrier  18  or on the image sensor  14  itself in some cases, mates with the flat top wall  45  holding the lens carrier  12  slightly above the surface of the adjacent circuit board  20 . Since the ledge  22  is substantially parallel to the imaging surface  28  when it supports the lens carrier  12  on the top wall  45  the barrel center axis  30  is positioned perpendicular to the imaging surface  28 . Optionally, the recess  42  might have steps  46  formed therein rising from the top wall  45  to allow for easy mating of the lens carrier  12  to different ledges  22  either on the image sensor  14  itself or formed on the chip carrier  18  mounting adjacent to and parallel with, the imaging surface  28 . Since the steps  46  would hold the mounted lens carrier  12  substantially flat, the barrel center axis  30  is positioned perpendicular to the imaging surface  28  and as is shown, the lens axis would also be perpendicular to the imaging surface  28  when mounted in the lens barrel  32  of the device  10 . A simple machining of the steps  46  rendering their bottom surface perpendicular to the barrel axis  30 , instead of the entire top wall  45  would be all that would be required to adjust the positioning. Also the steps  46  require much less machining to make for a flat engagement of the ledge  22  and the surface of the steps  46  with the lens carrier  12  thereby held slightly elevated above the circuit board  20 . Another option provided would be a second recess  43  formed in the top wall  45  and sized to accommodate a filter mounting therein. This second recess  43  would provide a mount for a filter should it be required. 
     Also shown in FIG. 4 are a means for self centering of the barrel center axis  30  and when mounted, over the center point  26  in the form of mounting clips  48 . There are four mounting clips  48  positioned in opposite pairs in notches  50  in the perimeter of the recess  42 . The clips  48  are flexible are formed in the recess  42  of the base  34  in positions to allow them to tilt into the notches  50  when forced by the perimeter edge of the chip carrier  18  or exterior of the image sensor  14  when no chip carrier  18  is used. The clips are formed such that they require a substantially equal force to deflect them away from the center point  26  when mounted and toward the recess  42  if included. The distal end of the clips  48  have a projection  54  formed thereon as a means to cooperatively engage with the side of the chip carrier  18  or the bottom of the chip carrier  18 . If the image sensor  14  is mounted without a chip carrier  18  then the projection  54  would engage directly with the side or bottom thereof. Of course a groove might be cut into the side of the chip carrier  18  or the image sensor  14  for better cooperative engagement with the projection  54  or other types of cooperative engaging shapes might be used and such are anticipated. 
     In use, the lens carrier  12  would be slid upon the chip carrier  18  or image sensor  14  with the recess  42  operatively engage around the perimeter thereof. A downward force on the lens carrier  12  causes the clips  48  to flex away from the center point  26  with equal force and toward the notches  50  and then rebound toward the barrel center axis  30  when the distal end  52  of the clip  48  would engage the side or bottom edge of the chip carrier  18  or image sensor  14 . Because it takes a substantially equal amount of force to flex the clips  48 , and because they are situated in opposite pairs or in an opposite pair for the minimum function, the force of the clips  48  naturally equalizes in both directions and self centers the lens barrel  32  and barrel center axis  30  and thus the lens center axis of a mounted lens  16  over the center point  26  while concurrently providing a means of cooperative engagement of the lens carrier  12  with the image sensor  14 . This embodiment is especially practical and preferred in instances where high volumes of lenses  16  must be mounted to image sensors  14  because of the reduction in adjustments that must be made since the device  10  is self centered, with the barrel center axis  30  perpendicular to the imaging surface  28  and cooperatively engaged with the image sensor  14  or the chip carrier  18  holding the image sensor  14 , all in one quick action. 
     Another preferred embodiment of the device  10  would have the lens carrier  12  and chip carrier  18  being made in a mating form designed to cooperatively engage with each other. As shown in FIG. 3 the lens carrier  12  could be made with clips  48  specifically dimensioned for the projections  54  to locate in grooves  56  formed in the side of the chip carrier  18  or just to engage the side of the chip carrier  18  in cooperative engagement. In this fashion chip carriers  18  could be manufactured in a kit having a plurality of differently configured chip carriers  18  configured to cooperatively engage with a variety of different image sensors  14  and thereafter engage with a variety of different mating lens carriers  12  which would easily mount in the aforementioned fashion. All of the chip carriers  18  would be designed to leave the lens carrier  12  slightly elevated above the circuit board  20  and to use the chip carrier  18  and lens carrier  12  cooperative mating as a mean of alignment of the lens carrier center axis  30  with the center point of the image sensor  14  and as a means of perpendicular alignment of the lens center axis with the imaging surface. This would be accomplished by the formation of a mating shoulder or ledge  22  on the chip carrier  18  matching the top wall  45  or steps  46  of the lens carrier  12  in the aforementioned fashion and the mounting clips  48  on the lens carrier  12  mating to the sides of the chip carrier  18  in the aforementioned fashion. 
     While all of the fundamental characteristics and features of the present invention has been described herein, with reference to particular embodiments thereof, a latitude of modification, various changes and substitutions are intended in the foregoing disclosure and it will be apparent that in some instances, some features of the invention will be employed without a corresponding use of other features without departing from the scope of the invention as set forth. It should be understood that such substitutions, modifications, and variations may be made by those skilled in the art without departing from the spirit or scope of the invention. Consequently, all such modifications and variations are included within the scope of the invention as defined by the following claims.