Abstract:
The present invention relates to a digital camera having an imager pixel array and memory for storing images from the array, the memory is programmable to non-rewritably store images for subsequent readout. The non-rewritable memory storage permits a low cost image storage enabling the camera to be disposable or reconditioned for reuse.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention relates generally to a photo image capturing device and more particularly to a disposable or recyclable digital camera.  
       BACKGROUND OF THE INVENTION  
       [0002]     Currently, disposable cameras are limited to film varieties. A traditional disposable camera includes film that is inserted during production and after the film is finished, the whole camera is taken to a film processing center where the film is developed and the printed images are returned to the customer.  
         [0003]     Solid state imaging devices having pixel arrays, including charge coupled devices (CCD) and complementary metal oxide semiconductor (CMOS) devices, are commonly used in photo-imaging applications. A CMOS imager circuit, for example, includes a focal plane array of pixel cells, each including a photosensor, for example, a photogate, photoconductor or a photodiode for accumulating photo-generated charge. Each pixel cell has a charge storage region, which is connected to the gate of an output transistor that is part of a readout circuit. The readout circuit connected to each pixel cell includes at least the output transistor, which receives photo-generated charges from the storage region and produces an output signal that is read-out through a pixel access transistor. In some imager circuits, each pixel may include at least one electronic device such as a transistor for transferring charge from the photosensor to the storage region and one device, also typically a transistor, for resetting the storage region to a predetermined charge level prior to charge transference.  
         [0004]     CMOS imagers of the type generally discussed above are generally known as discussed, for example, in U.S. Pat.No. 6,140,630, U.S. Pat. No. 6,376,868, U.S. Pat. No. 6,310,366, U.S. Pat. No. 6,326,652, U.S. Pat. No. 6,204,524 and U.S. Pat. No. 6,333,205, assigned to Micron Technology, Inc., which are hereby incorporated by reference in their entirety.  
         [0005]     An exemplary digital camera employing a solid state CMOS imager is illustrated in block diagram found in  FIG. 1 . As shown, an exemplary CMOS imager  308  has a pixel array  240  comprising a plurality of pixels arranged in a predetermined number of columns and rows, with each pixel cell being constructed as described above. Attached to the array  240  is signal processing circuitry. The pixels of each row in array  240  are all turned on at the same time by a row select line, and the pixels of each activated row are selectively output by respective column select lines. A plurality of row and column select lines are provided for the entire array  240 . The row lines are selectively activated by a row driver  245  in response to row address decoder  255 . The column select lines are selectively activated by a column driver  260  in response to column address decoder  270 . Thus, a row and column address is provided for each pixel.  
         [0006]     The CMOS imager  308  is operated by the timing and control circuit  250 , which controls address decoders  255 ,  270  for selecting the appropriate row and column lines for pixel readout. The control circuit  250  also controls the row and column driver circuitry  245 ,  260  such that they apply driving voltages to the drive transistors of the selected row and column select lines. The pixel column signals, which for a CMOS imager typically include a pixel reset signal (V rst ) and a pixel image signal (V sig ), are read by a sample and hold circuit  261 . V rst  is read from a pixel immediately after a charge storage region is reset. V sig  represents the amount of charges generated by the pixel&#39;s photosensitive element and stored in the charge storage region in response to applied light to the pixel. A differential signal (V rst - V sig ) is produced by differential amplifier  262  for each pixel. The differential signal is digitized by analog-to-digital converter  275  (ADC). The analog-to-digital converter  275  supplies the digitized pixel signals to an image processor  280 , which forms and outputs a digital image.  
         [0007]     A removable repeatably rewritable memory  281  is typically associated with the image processor  280  and/or another camera processor  282  for storing the digital image. Alternatively separate memories may be respectively associated with each of the processors  280 ,  282 , with one containing an outputted image being removable. Typical digital cameras are costly in part because the rewriteable memory associated with the processor  280  and/or  282  is expensive.  
       BRIEF SUMMARY OF THE INVENTION  
       [0008]     The present invention relates to a low cost digital camera having a one time programmable memory for storing the digital images acquired by a connected digital imager. Because of the lowered costs associated with the one time programmable memory, the digital camera may be disposable or recyclable, whereby the user has the advantages of a digital camera in a disposable and/or recyclable low cost form. The camera permits a user to directly download images onto to a computer or other storage device or optionally remove the one-time programmable memory chip to store and read the stored images. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The foregoing and other advantages and features of the invention will become more apparent from the detailed description of exemplary embodiments provided below with reference to the accompanying drawings in which:  
         [0010]      FIG. 1  illustrates a conventional imager device;  
         [0011]      FIG. 2  illustrates an imager and memory device according to an embodiment of the invention;  
         [0012]      FIG. 3  illustrates an imager and memory device according to another embodiment of the invention;  
         [0013]      FIG. 4  illustrates the outer view of a disposable digital camera constructed in accordance with an embodiment of the invention;  
         [0014]      FIG. 5  illustrates an internal circuitry of a disposable digital camera constructed in accordance with an embodiment of the invention;  
         [0015]      FIGS. 6A and 6B  illustrate exemplary operational embodiments of the invention; and  
         [0016]      FIGS. 7A, 7B ,  7 C,  7 D and  7 E illustrate additional exemplary operational embodiments of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]     In the following detailed description, reference is made to the accompanying drawings, which are a part of the specification, and in which is shown by way of illustration various embodiments whereby the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to make and use the invention. It is to be understood that other embodiments may be utilized, and that structural, logical, and electrical changes, as well as changes in the materials used, may be made without departing from the spirit and scope of the present invention.  
         [0018]     The digital camera of the present invention includes a one time programmable memory, also termed non-rewritable memory  28  having associated programmable elements  29 , in place of the reprogrammable memory  281  typically associated with the solid state imager  308 .  
         [0019]     A first exemplary embodiment of the invention is illustrated in  FIG. 2 . A CMOS imager  308 , of the type depicted in  FIG. 1 , or another CMOS, CCD or other solid state imager, is provided for capturing and producing digital images. The digital images are stored in memory  28  having associated programmable elements  29 , which are selectively programmed to make the images stored in memory  28  non-rewritable. The illustrated CMOS imager  308  includes an integrated image processor  280  for loading image data from an analog-to-digital converter  275  into the one time programmable memory  28 , programming the programmable elements  29 , and for managing readout of that data. In this regard, the imager  308  of  FIG. 2  may be the same as illustrated in  FIG. 1 , with a one time programmable memory  28  and associated programmable elements  29  used in place of rewriteable memory  281 . The image data may be processed by processor  280  before it is stored in the one time programmable memory  28 . A low grade, inexpensive, processor  280  may be used to transfer the pixel data from the analog-to-digital converter  275  into the memory  28  and programmable elements  29 .  
         [0020]     The one time programmable memory  28  stores digital camera images for later retrieval. The one time programmable memory  28  has multiple image storage areas for storing multiple images. However, it is contemplated that the memory  28  may also only include a single storage area for storing only one image. Upon image capture and storage in memory  28 , the processor  280  applies a programming voltage to the programmable elements  29 . The programmable elements  29  are associated with image storage areas and are formed as fuses or anti fuses. The programmable elements  29  are part of the one time programmable memory  28  which, when programmed by the processor  280 , cause stored images to become non-rewritable. The processor  280 , upon storing an image within memory  28 , will also program the programmable elements  29  and cause stored images to be non-rewritable. If the programmable elements  29  are not programmed, the image data is not permanently stored in the memory  28  and can be erased and rewritten. Each image storage area of the one time programmable memory  28  may have its own programmable element  29  to set the image storage area as non-rewritable. Alternatively, once the memory  28  is full, the image processor  280  may program a single programmable element  29  to make all of the image storage areas of memory  28  non-rewritable. A particular memory format is not critical to the invention. Any memory formats suitable for use with a digital camera may be employed, including formatting the memory to one of the standards of Secure Digital Memory or CompactFlash®, for example.  
         [0021]     An alternate exemplary embodiment of the invention is illustrated in  FIG. 3  in which the solid state imager  308  includes a memory controller  380  to store raw image data into memory  28  and program the programmable elements  29  to make the stored images non-rewritable. In this embodiment, the image processor, e.g. element  280  in  FIG. 2 , can be omitted to further reduce costs. In this embodiment only raw image data from the output of the analog-to-digital converter  275  is stored in memory  28 . Any needed or desired image processing may later be done on the stored images by a computer or by a traditional print processing lab.  
         [0022]      FIGS. 4 and 5  depict a disposable and/or recyclable camera  10  containing memory  28  and associated programmed elements  29 . The user may access the camera memory  28  for image readout in different ways. As shown in  FIGS. 4 and 5 , the camera housing  14  includes at least one port  20  that allows the user to directly or wirelessly connect to an external computer or other device to read and copy the image data stored on the one time programmable memory  28 . The camera processor  282  controls access to the memory  28  through the ports  20 . For example, the connection methods may include a USB cable or USB memory. Additionally, the user has the ability to remove the memory  28  from the camera housing  14  itself. The user may remove the memory  28  and access the accessible images using commercial reading devices, including a card reader or a printer.  
         [0023]     The illustrated camera  10  may include use of a single focal length lens  16  or multiple and/or more complex lenses may be used. Optionally, the camera housing  14  may allow for the attachment of additional lenses. The lens  16 , and pixel array of an imager, e.g. imager  308  ( FIG. 2 ) or  308 ′ ( FIG. 3 ), (not shown in  FIG. 4 ) and an aperture  18  are optically aligned, as known in the art. The lens  16  and aperture  18  control the amount of light that reaches and is processed by the imager, e.g.  308  or  308 ′. The system may include a shutter system or the imager array can be turned on and off, by the camera processor  282 , to act as a mechanical shutter would. A CMOS imager, e.g.  308  or  308 ′, or other imager, will process the data in the pixel array  240  to produce image data for storage in memory  28 .  
         [0024]     As with disposable film cameras, the camera housing  14 , illustrated in  FIGS. 4 and 5 , must be made of sturdy but inexpensive material, such as e.g., plastic. The housing  14  may also include parts made from metal, cardboard or other sturdy and inexpensive material. A button  30  is connected on top of the camera housing  14  for taking the picture, which will either open the shutter system or will turn the imager array on to allow it to collect image data, as depicted in  FIGS. 4 and 5 . The camera housing  14  may include an opening in its front and back walls  34 ,  36 , which are aligned to act as a viewfinder  12 . Optionally, the camera may include a flash  24 , controlled by the camera processor  282 , for providing additional light while an image is being recorded by the imager, e.g.  308  or  308 ′. The camera  10  functions are powered through the use of a battery  32  which may be removable.  
         [0025]     Once the memory  28  is full, the camera  10  is no longer usable without replacement of the memory  28 . It should be appreciated, the memory  28  and/or camera  10  may optionally be reconditioned by an authorized reconditioner (recycling) or the user can dispose of the camera after downloading the stored image(s) or removing the memory  28 . The camera  10  may be reconditioned by inserting a new programmable memory card  28  in the camera housing  14  and resetting all counters. Reconditioning and resetting may only be done by an authorized dealer.  
         [0026]     Operations preformed by the image processor  280  of  FIG. 2 , or the memory controller  380  in  FIG. 3  in storing images in memory  28  and making them non-rewritable are now described in greater detail.  FIG. 6A  depicts the steps taken to store an image using either one programmable element  29  per one pixel storage area of memory  28  or one programmable element  29  per one image storage area of memory  28 . First, the user operates the camera  10  to take a picture at step  500 . The image is stored in the storage area of the memory at step  502  and then made non-rewritable at step  504  by the programming of one or more programmable elements  29 . If the total number of pictures stored by the memory is equal to the memory  28  storage capacity as determined at step  506 , no further pictures can be taken at step  508 . When the total number of images is not equal to capacity, the user may operate the camera  10  to take another picture at step  500 . In this embodiment, there is either one programmable element  29  for each pixel data stored in memory  28 , that is, one element for each pixel of array  240 , or one programmable element  29  for the memory storage area of an entire image.  
         [0027]     An exemplary operational alternative embodiment, shown in  FIG. 6B , allows for the implementation of a single programmable element  29  to make all of the images stored in the entire memory  28  non-rewritable at once. The user operates the camera  10  to take a picture at step  500 . The image is stored in the storage area of the memory  28  at step  502  and if it is determined that the number of images equals the storage capacity of the memory at step  506 , all of the images are made non-rewritable in step  507  by programming of a programmable element  29 . If the total number of pictures does not equal the memory  28  storage capacity as determined in step  506 , the user may take an additional picture at step  500  until the storage capacity of memory  28  is reached and all images are made non-rewritable in step  507 .  
         [0028]     In another exemplary operation embodiment, the programmable memory  28  may also be designed to allow the user to discard several unwanted images. In the operations depicted in  FIGS. 6A and 6B , exemplary operational embodiments the camera user can take a set number of pictures corresponding to the capacity, i.e. number of image storage areas, of memory  28 . In another operational embodiment depicted in  FIG. 7A , the user can take more than a set number of pictures, but the user will be required to delete or deselected the extra images. Thus, as illustrated in  FIG. 7A , after a set of number of images are stored, which exceed the number of images permitted for the user to store and reproduce, the user may select images previously taken and stored in memory  28  that they want to keep as later accessible for readout. In this embodiment, a flag in each storage area will hold information identifying if the picture is accessible for readout. If a flag is set to non-accessible, the user will not be able to access the image for readout, although it is stored in memory  28 . In this operational use, after the images are stored and made non-rewritable, an initial operational step clears a counter  600 . The user then selects a stored image as accessible at step  602  and a flag is set for later image access at step  604 . A count of one is added to the counter at step  606 . If the total number of pictures permitted for access is not met at step  608 , the user may select another image to flag for access and readout at step  602 . Alternatively, if the number of images to be accessed equals the number of images selected at step  608 , the user cannot select any additional images at step  610 . With this embodiment a user may operate a camera  10  to take a larger number of images which are non-erasably stored in memory  28 , but only those flagged as accessible are capable of being readout. Instead of flagging these images as accessible for readout in the  FIG. 7A  embodiment, the process can also be arranged so the user flags the non-accessible image, permitting readout of only the non-flagged images from memory  28 .  
         [0029]      FIG. 7B  depicts yet another operational embodiment where the user may select the acquired images that they want to keep as accessible, as the images are acquired. In this embodiment the user decides whether to keep an image immediately after it is taken. First, the user operates the camera  10  to take a picture at step  612  and the image is stored in memory at step  614 . If the user decides to keep the image at step  616 , the image is flagged as accessible for readout at step  620 . If the user decides not to keep the image at step  616 , the image is flagged as non-accessible at step  618 . One or more programmable element(s)  29  are then programmed, at step  622 , to make the image in memory  28  non-rewritable, regardless of how it is flagged. It is next determined whether the total number of images taken is less than memory  28  capacity at step  624 . If the total number of images taken equals the memory  28  capacity, the user cannot take any more pictures at step  628 . However, if the number of pictures taken is less than the number allowed as determined in step  624 , the total number of images selected as accessible is compared to the number of allowed accessible images at step  626 . If the user has taken less than the total number of allowed accessible images at step  626 , the user may take another image at step  612 . If the number of accessible images is equal to the number of allowed accessible images, the user cannot take any additional pictures at step  628 .  
         [0030]     In yet another operational embodiment illustrated in  FIG. 7C , the images can be non-erasably stored into memory  28  after all of the images have been taken. First, the user operates the camera  10  to take a picture at step  612  and the image is stored in memory at step  614 . If the user decides to keep the image at step  616 , the image is flagged as accessible at step  620 . If the user decides not to keep the image at step  616 , the image is flagged as non-accessible at step  618 . It is next determined whether the total number of images taken is less than memory  28  capacity at step  624 . If the total number of images taken equals the capacity the user cannot take any more pictures at step  628  and the programmable element  29  is used to make all stored images non-rewritable at step  622 . However, if the number of pictures taken is less than the number allowed as determined in step  628 , the total number of images selected as accessible is compared to the number of allowed accessible images at step  626 . If the user has taken less than the total number of allowed accessible images at step  626 , the user may take another image at step  612 . If the number of accessible images is equal to the number of allowed accessible images, the user cannot take any additional pictures at step  628  and one or more programming elements  29  are programmed to make all stored images in memory  28  non-rewritable in step  622 .  
         [0031]     In yet other operational embodiments illustrated in  FIG. 7D and 7E , the user may choose not to keep an image before it is stored in memory  28 . Referring first to  FIG. 7D , the user operates the camera  10  to take a picture at step  612  and the user decides whether to keep the image at step  616 . If the image is not selected to be retained, the user may take another image at step  612 . If the user decides to retain the image, the image is stored in memory  28  at step  614  and made non-rewritable by programming one or more programmable elements at step  622 . In step  621  the number of images is checked to determine whether the total number of images stored equals the memory  28  capacity at step  621 . If the number of images is less than the capacity, the user may take another picture at step  612 . If the total number of pictures taken equals capacity, then the user cannot take any more pictures at step  628 .  
         [0032]     Referring to the operational embodiment in  FIG. 7E , the user operates the camera  10  to take a picture at step  612  and the user decides whether to keep the image at step  616 . If the image is not selected to be retained, the user may take another picture at step  612 . If the user decides to retain the image, the image is stored in memory  28  at step  614 . The number of images stored is then compared to the memory  28  capacity, in step  621 , to determine whether the total number of images stored equals the memory  28  capacity. If the number of images equals capacity, all stored images are made non-rewritable in memory  28  by programming one or more programmable elements  29  at step  622  and the user cannot take any more pictures at step  628 . If the number of images is less than the capacity, the user may take another picture at step  612 .  
         [0033]     Some of the embodiments described above employ a counter which is incremented up, however, it is contemplated that the counter may also be implemented by counting down to a preset number. Additionally, both the initial and ending values of the counter can be set to any predetermined number.  
         [0034]     In all the forgoing operational embodiments, the illustrated processing may be conducted by the image processor  280  in the  FIG. 2  embodiment or by the memory controller  380  in the  FIG. 3  embodiment.  
         [0035]     The processes and devices described above illustrate exemplary methods and devices of many that could be used to implement the invention. The above description and drawings illustrate exemplary embodiments of the present invention. However, it is not intended that the present invention be strictly limited to the above-described and illustrated embodiments and is only limited by the scope of the appended claims.