Abstract:
Image sensor module architecture provides flexible mounting of illuminators in an imaging apparatus with flexible fasteners. The architecture involves one or more LED-based illuminators that may be mounted adjustably to provide high intensity and uniform profile luminescence. The supporting imaging and electronic circuit components are quickly assembled and disassembled from the image sensor module by using a flexible multi-function clip having multiple segments for holding multiple objects together.

Description:
BACKGROUND  
       [0001]     All references cited in this specification, and their references, are incorporated by reference herein where appropriate for teachings of additional or alternative details, features and/or technical background.  
         [0002]     Disclosed is image sensor module architecture related to imaging devices in general and to compact scanners in particular.  
         [0003]     Known image sensor module architectures have limitations, such as large dimensions, not being able to accommodate higher intensity document illuminators and excessive assembly and disassembly times. These aspects can be overcome through architectural alterations which are described herein.  
         [0004]      FIG. 1   a  illustrates a cross section of a typical common image sensing module  20  positioned underneath a glass platen  10  of a scanner. Image sensing module  20  includes a light source  45 , optical system  33  and an image sensor (not shown) on circuit board  80 . A document handler  15  feeds a document  5  over the platen. As the document passes over image sensing module  20 , the document is illuminated by light source  45 , through aperture  35  guided by illuminator  40 . Illuminators  40  are housed in housing  50 . The light reflected by document  5  is then focused through optical path  30  by optical lens system  33  onto image sensors. Image sensors, such as charge coupled devices (CCDs), typically have a row or linear array of photosensors with suitable supporting circuitry integrated onto a circuit board  80 . When the document moves past the linear array, each of the photosensors converts reflected light from the original image into electrical signals, which in turn can be converted into digital data.  
         [0005]     A perspective view of the image sensing module  20  is also shown in  FIG. 1   b  with similar numerals referring to similar parts of  FIG. 1   a.  As is seen in both Figures, circuit board  80  is mounted onto the body  60  of module  20  by means of fasteners, such as screws  90 . The circuit board is offset from the body of the module with standoffs by an amount to accommodate other components, such as a connector in the middle, thus increasing the overall height h of the module. Furthermore, the overall width, w, of the module is governed by the width of the individual low-profile illuminators  40 . It is often difficult to make the illuminators laterally short enough to fit within the limited space of compact scanners having a short focal distance along the optical path  30 . In addition, it is known that the present image sensor modules are configured to be positioned at a fixed position for a specified platen glass thickness, t, as shown in  FIG. 1   a.    
         [0006]     In order to satisfy the needs for even more compact and more powerful scanners, it is desirable to reduce the over-all dimensions of the image sensor modules while at the same time providing even larger illuminators for enhanced luminescence in scanning a document. It is also desirable to allow for the illuminators to be fully adjustable for optimum performance for any platen glass thickness, or for no glass at all. Further, improved fasteners for quick assembly and disassembly of the circuit board and supporting electronics boards would also improve the overall architecture of the image sensor module system.  
       SUMMARY  
       [0007]     Aspects disclosed herein include  
         [0008]     an illuminator assembly comprising at least one angled illuminator and one angled reflector, or only one illuminator, each of the illuminators being operatively held to the assembly so as to be vertically adjustable with respect to its angled position;  
         [0009]     an image sensor assembly having a body configured to accept one or more angled illuminators; an optical system having an optical path arranged between the illuminators to receive cooperatively light rays reflected from an object illuminated by the one or more angled illuminators; an imaging board capable of converting the light rays into electrical signals; a processing board capable of converting the electrical signals into an electronic image; and a multi-function clip configured to secure the imaging board and the processing board to the body comprising the image sensor assembly; and  
         [0010]     a device comprising a flexible body having a top surface, a bottom surface and a back surface; the top surface having a top front end and a top back end; the bottom surface having a bottom front end and a bottom back end; a top lever partially cleaved from the top surface, the top lever having a bent portion forming the top back end and extending beyond the back surface; a bottom lever partially cleaved from the bottom surface, the bottom lever having a bent portion forming the bottom back end and extending beyond the back surface; the back surface formed to comprise one or more legs connecting the top surface to the bottom surface; wherein the device is configured to form a multi-function clip to snap on to multiple objects with multiple protrusions formed on the top surface, the bottom surface and the back surface. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0011]      FIG. 1   a  is a drawing showing a cross sectional view of an arrangement of document illuminators in an image sensor module used in scanners;  
         [0012]      FIG. 1   b  is a perspective drawing of the image sensor module shown in  FIG. 1   a;    
         [0013]      FIG. 2   a  is a drawing of an embodiment showing a perspective view of an image sensor module with an exploded view of the components that comprise the image sensor module, including the disclosed multi-function clips;  
         [0014]      FIG. 2   b  is a cross sectional drawing of the image sensor module of  FIG. 2   a  showing an angled architectural aspect of the placement of illuminators in relation to a platen and electronic components that are held in position by means of a flexible multi-function clip;  
         [0015]      FIGS. 3   a  and  3   b  are drawings of an embodiment showing the flexibility in adjusting the focal distance between the angled illuminators and the platen for different thicknesses of the platen without having to modify the image sensor module;  
         [0016]      FIG. 4  is a drawing of another embodiment showing the various segments of a multi-function clip that is capable of holding multiple components of an image sensor module.  
     
    
     DETAILED DESCRIPTION  
       [0017]     In embodiments there is illustrated architecture for a compact, cost effective image sensor module used in imaging devices. The disclosed architecture comprises a member having a light-receiving element defining a main plane, and a light guide defining a main surface, the plane and the surface being disposed at an angle of about 30 degrees to about 90 degrees, or about 45 degrees to about 90 degrees.  
         [0018]     In one embodiment there is disclosed an illuminator assembly comprising one angled illuminator, or tow angled illuminators, or one angled illuminator and one angled reflector, at least one angled illuminator and one angled reflector, each of illuminators or reflector being operatively held to the assembly so as to be vertically adjustable with respect to its angled position. The disclosed non-planar configuration circumvents the problem of not being able to fit an image sensor module in compact scanners that require short focal distance within available height restrictions, as explained further below. Unlike known architectures, the present architecture provides adjustable positioning of the image sensor module with respect to a transparent platen, independently of the thickness of the glass. The architecture also incorporates simplified flexible fasteners for holding the image sensor module against circuit boards, thus enabling a compact and versatile module.  
         [0019]      FIG. 2   a  shows a perspective view of an image sensor module  200  having a body  210  configured to hold an illuminator  270 , an image sensor board  220  and various electronic boards with the aid of a multi-function clip  230 . The electronic boards comprise a video processing board  250  and light source driver boards  240  shown in  FIG. 2   a.  Although not limited to any particular configuration, the multi-function clip  230  shown in  FIG. 2   a  is operative to hold both the image sensor board  220  and the electronic boards with two-sided outside levers  233  and inside claws  235  (see  FIG. 4 ). The outside levers are configured to snap over the edges of the respective electronic boards, while the inside claws snap over the image sensor board  220 .  
         [0020]     Light source  260  is positioned, though not limited to, at a central portion of the image sensor module  220 . The light source comprises, though not limited to, a side emitting LED, which may be an integral part of an illuminator  270  better seen in  FIG. 2   b.  A heat sink  290  provides a means for dissipating heat from the light source. As described in more detail in the related application Ser. No. 10/995,462, an illuminator  270  may be an LED-based illuminator formed with one or more optical notches (not shown) and totally encased in a white surround  280  to yield total internal reflection of the light rays emanating from an illuminator  270 . The reflected light rays are collected at an aperture  275  which in turn transmits high power and highly uniform illumination profile to illuminate a document (not shown) on platen  300 .  
         [0021]      FIG. 2   b  shows a cross sectional view of the image sensor module disclosed in  FIG. 2   a.  Image sensor module  200  is positioned below a platen  300 . In one aspect of the embodiment disclosed in  FIG. 2   b,  the illuminator assembly comprises one or more illuminators  270  operatively angled with respect to each other. In one embodiment, each of the illuminators may operatively be vertically adjusted with respect to its angled position to attain a gap g in relation to the platen as seen in  FIG. 2   b.    
         [0022]     In another aspect, a representative flexible clip  230  holds the image sensor board  220  with one set of claws  233  facing the platen  300  and the electronic support boards with another set of levers  235  facing away from the platen.  
         [0023]     It will be understood from the aspects of the embodiments disclosed herein that the angled architecture of one or more illuminators provide the flexibility of accommodating larger illuminators with more light intensity and more uniform luminosity than what is presently available. It will be appreciated that a horizontally positioned illuminator serving platen  300 , for example, can be only as large as, and not larger than the active region r of the platen shown in  FIG. 2   b.  That region r would not be able to accommodate two horizontal illuminators (with chamfered apertures directed at the platen) of their size. However, by positioning them at angles Φ and θ from about 45 to about 60 degrees measured from the optical path  310  shown in  FIG. 2   b,  two illuminators can be readily harnessed to enhance the illumination of a document (not shown) on platen  300 . Angles Φ and θ can be independently varied from about 45 to about 90 degrees in order to customize the luminosity desired at the platen. It will be noted that an angle of 90 degrees would approximate a horizontal position, while an angle of 0 degrees would approximate a vertical position. While a horizontal position would accommodate one illuminator for the most compact dimension r, a bundle of illuminators can be positioned with their apertures  275  facing upwards. It is also possible that an illuminator may be a passive reflector reflecting light rays from an adjacent LED illuminator to a document placed on a platen, for example.  
         [0024]     In operation, the light reflected by the document illuminated on the platen is focused through optical path  310  by optical lens system  320 , such as rod lens array, onto image sensors  225  which may comprise charge coupled devices (CCDs) arranged in rows or linear arrays on the video processing board  250 . When the document moves past the linear array, each of the photosensors converts reflected light from the original image into electrical signals, which in turn can be converted into digital data. For enhanced focusing conditions, the focusing distance along the optical path  310  may be adjusted by adjusting the gap g between the platen and the image sensor module as shown in  FIG. 2   b.    
         [0025]     It is common practice to incorporate document illuminators into image sensor modules in a fixed position.  FIGS. 3   a  and  3   b  disclose an aspect which allows flexible positioning of the illuminator(s) to yield maximum light intensity for platen glasses of different thicknesses. For example, in  FIG. 3   a,  the upper surface of platen  300  is positioned at a datum plane  350 . Platen  300  has a. thickness t which is different from platen  300 ′ having a thickness t′ shown in  FIG. 3   b.  In order to attain optimal luminosity, illuminators  270  may be repositioned for an optimal focus distance without having to disassemble the image sensor module  200 . The positioning is accomplished by mounting the illuminators slidably on to member  290 , which serves the function of both a heat sink and a holding structure. Member  290  may be angled as shown in  FIG. 2   b  to conform to the structural architecture of the image sensor module, and may comprise aluminum or any other material with high thermal conductivity.  
         [0026]     In an aspect shown in  FIG. 4 , the assembly of the components of the disclosed image sensor shown in  FIG. 3   a  is accomplished by actuating finger operable levers  233  and  233 ′ of the double-sided multi-function clip  230  having multiple snappable protrusions. That is, by pressing together the levers  233  and  233 ′, forming a first set of protrusions, jaws  235  and  235 ′, forming a second set of protrusions, open up to accept and firmly snap onto the edges of the image sensor board  220  shown in  FIG. 2   a.  Although not limited to any particular configuration, the multi-function clip  230  shown in  FIG. 2   a  is operative to hold both the image sensor board  220  and the electronic boards with two-sided outside levers  233  and inside claws  235  (see  FIG. 4 ). The outside levers are configured to snap over the edges of the respective electronic boards, while the inside claws snap over the image sensor board  220 . The assembly comprising one or more of the clips  230  now secured to the back of the image sensor board  220  may be engaged to a rail (not shown) under the lip  215  of body shown in  FIG. 2   a.  The flexible spring leaves  231  and  231 ′ that connect jaws  235  and  235 ′ to protrusions  233  and  233 ′ flex under lip  215  to hold the multi-function clip  230  snapped to the body of the multi-function clip  230 . The other components such as the LED driver boards  240  and the video processing board  250  are secured from the rear of the clip by urging the components to slide in between the levers  233  and  233 ′. Accordingly, components including the image sensor board  220 , the light source driver boards  240  and the video processing board  250  are secured onto the body  210  of the image sensor module  200  by means of a single double-sided flexible clip  230 . The flexible clip may comprise a suitable springy material such as steel or plastic.  
         [0027]     In more detail, the multi-function clip disclosed in  FIG. 4  comprises a flexible body having a top surface  237 , a bottom surface  237 ′ and a back surface  239 . The top surface has a top front end  235  and a top back end  233  while the bottom surface has a bottom front end  235 ′ and a bottom back end  233 ′. A top lever  231  is partially cleaved from the top surface. The top lever has a bent portion forming the top back end  233  and extending beyond the back surface  239 . Similarly, a bottom lever  231 ′ is partially cleaved from the bottom surface  237 ′. The bottom lever has a bent portion forming the bottom back end  233 ′ and extending beyond the back surface  239 . The top and bottom levers  231  and  231 ′ are cambered upwards and downwards, respectively, to provide springy snap action when engaged with an object surrounding the two levers. At the same time, the top and bottom bent portions  233  and  233 ′, which are oriented upwardly and downwardly, respectively, provide a finger squeeze action to open up the two front jaws  235  and  235 ′ for engaging an object presented at the front end of the multi-function clip. The upper  235  and lower  235 ′ jaws are oriented downwardly and upwardly, respectively.  
         [0028]     Further, the back surface  239  is formed to have an opening in the middle to form a pair of legs  239 ′ and  239 ″ connecting the top surface  237  to the bottom surface  237 ″, as shown in  FIG. 4 . The pair of legs is cambered inwards towards said upper and lower jaws to provide a spring body. It will be understood that there could be multiple number of legs cambered inwards or backwards to the front of the clip, and the orientation of the camber may be alternated between successive legs.  
         [0029]     It will be appreciated by workers in the field that the quick assembly so described above also allows quick disassembly, in contrast to procedures involving stand-offs and screws that are commonly used with image sensor modules such as shown in  FIG. 1   b.  The disassembly is accomplished in reverse order by removing the multi-function clip  230  and board assembly from the body  210  of the image sensor module  200 , releasing the image sensor board  220  from the front jaws  235  of the clip and then sliding off the video processor board and driver boards from the rear finger actuated levers  233  and  233 ′ shown in  FIG. 4 . It will be understood that the disclosed flexible clip is not limited to that which is shown in  FIG. 4 .  
         [0030]     It will be appreciated that variations of the above-disclosed embodiments and other features and functions, or alternatives thereof, may be desirably combined into many other different devices or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.