Abstract:
A memory device including a connector enabling the memory device to be coupled to a power source; a display including a bar indicator that indicates an amount of remaining storage space available in the memory device, wherein the display responds to the power source when the memory device is coupled to the power source to display information related to storage space availability on the bar indicator and continues to display such information after the memory device is uncoupled from the power source so that no power is applied to the display.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application is a divisional of U.S. patent application Ser. No. 09/669,178 filed Sep. 25, 2000. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to cameras having removable image bearing media.  
       BACKGROUND OF THE INVENTION  
       [0003]     Current silver halide film cameras have displays for indicating settings and status conditions, such as frame number, of the camera. Often, the display uses twisted nematic liquid crystals that that requires continuous electrical drive to display information. Cameras with this type of display are usually turned on only for short periods of time to preserve battery life. When the cameras are turned off, the liquid crystal display goes blank. An operator must turn on the camera to determine the status of the camera. These cameras typically incorporate a high voltage supply to drive an electronic flash built into the camera, and utilize cartridges that contain the film in a light tight environment.  
         [0004]     Many digital cameras use liquid crystal displays to display a captured image. Displays in these cameras are also nematic liquid crystals displays that can drain an electronic camera power supply in a short period of time.  
         [0005]     Many digital cameras also use removable memory cards to store images. There is no way to tell how much capacity remains or what images reside on these memory cards without turning the camera on.  
       SUMMARY OF THE INVENTION  
       [0006]     Accordingly, it is an object of the present invention to provide a convenient way for a viewer to view a display on an image bearing medium whether in the camera or removed from the camera for viewing.  
         [0007]     It is another object of the present invention to provide a convenient way to view the display on image bearing medium that presents an indication of camera status to the user.  
         [0008]     It is another object of the present invention to provide a camera with a display on the image bearing medium that presents the indication of camera status to the user.  
         [0009]     It is another object of the present invention to provide a means for changing the display on the image bearing medium prior to removal from the camera such that the display reflects the status of the image bearing media and not necessarily the camera.  
         [0010]     These objects are achieved by a memory device comprising:  
         [0011]     a connector enabling the memory device to be coupled to a power source;  
         [0012]     a display including a bar indicator that indicates an amount of remaining storage space available in the memory device, wherein the display responds to the power source when the memory device is coupled to the power source to display information related to storage space availability on the bar indicator and continues to display such information after the memory device is uncoupled from the power source so that no power is applied to the display.  
         [0013]     It is a feature of the present invention that a display is provided on a removable image bearing medium and can be viewed either in the camera or after removal from the camera.  
         [0014]     Another feature of the invention that the display itself can be made detachable from the image bearing medium and reused. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is a top sectional view of a silver halide camera with a film cartridge with a memory display;  
         [0016]      FIG. 2  is a top sectional view of an electronic capture camera with a removable memory card with a memory display;  
         [0017]      FIG. 3  is a side sectional view of the memory display of  FIG. 1 ;  
         [0018]      FIG. 4  is a top view of the memory display of  FIG. 3 ;  
         [0019]      FIG. 5  shows an electrical circuit which drives the display of  FIG. 3  by selectively coupling the flash unit high voltage supply to the display;  
         [0020]      FIG. 6A  is a partial top view of the memory display of the electronic capture camera of  FIG. 2 ;  
         [0021]      FIG. 6B  is a magnified view of the memory display of  FIG. 6A ;  
         [0022]      FIG. 7  is an electrical schematic circuit which drives the memory display of  FIGS. 6A and 6B ;  
         [0023]      FIG. 8A  is a waveform to drives a memory material to a reflecting, or bright condition;  
         [0024]      FIG. 8B  is a waveform to drives a memory material to a transmitting, or dark condition;  
         [0025]      FIG. 8C  is a waveform to drive a memory material to an intermediate condition between transmission and reflection;  
         [0026]      FIG. 9  is a view of a memory card with a memory display;  
         [0027]      FIG. 10  is a view of a film camera with a visible memory display on the image bearing medium;  
         [0028]      FIG. 11  is a view of an electronic camera with a visible memory display on the image bearing medium; and  
         [0029]      FIG. 12  depicts a memory card which incorporates a detachable display. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]     A top sectional view of a silver halide film camera  10  is shown in  FIG. 1 . A film cassette  20  with a memory display  37  in camera  10  holds a strip of film  22  that captures images from optic  26 . Film  22  is sequentially taken up onto take-up spool  24  to capture a set of images. After image exposure is complete, film  22  is returned to film cassette  20 . Camera controller  30  receives commands from an operator and controls the sequential motion of film  22  and optic  26 . Camera controller  30  can provide supplemental illumination to a scene by discharging a high voltage pulse through flash tube  42  in a flash unit. Flash tube  42  requires a flash capacitor  40  to store energy for flash tube  42 . Flash capacitor  40  typically stores energy in a capacitor having over 50 micro-farads capacitance at over 100 volts.  
         [0031]     The status of camera  10  is shown on a display  35  in camera  10 . Typically, display  35  shows the number of the current frame of film, the operational mode of flash tube  42 , and operating parameters of optic  26 . The status of the camera  10  can also be shown on the memory display  37 . In more complex cameras, display  35  is a conventional nematic liquid crystal display. Nematic liquid crystal fluids act in conjunction with polarizing filters to act as a shutter to reflect or transmit light. Transmitted light is selectively reflected from a surface behind the display to provide light indicia. The reflected light provides a white indicia. When light is blocked by the polarizing filters, the imager area is dark. Nematic liquid crystals must have a continuous electrical field across the display to display information.  
         [0032]      FIG. 2  is a top sectional view of an electronic camera  12 . Many of the components operate as in conventional camera  10 . Film  22  is replaced by electronic sensor  50 . Electronic sensor  50  captures a scene and camera controller  30  stores a captured image in removable memory card  52  with memory display  54 . The status of the electronic camera  12  can be shown on the memory display  37 . Display  35  in electronic camera  12  displays the status of electronic camera  12 , and in certain cases displays images from removable memory card  52 . The flash tube  42  is often provided in electronic camera  12  to supply additional light to a scene at the time of image capture. Flash tube  42  requires the flash capacitor  40  to store energy for flash tube  42 . Flash capacitor  40  typically stores energy in a capacitor having over 50 micro-farads capacitance at over 100 volts.  
         [0033]      FIG. 3  is a diagram of display  35  in accordance with the present invention. Memory material  60  is disposed between a transparent top conductor  62  and a bottom conductor  64 . Bottom conductor  64  can be a transparent electrical conductor such as Indium-Tin-Oxide or a light absorbing conductor formed by an oxide of a metal such as platinum or nickel. Memory material  60  can be a chiral doped nematic liquid crystal such as those disclosed in U.S. Pat. No. 5,695,682. Applied fields of various intensity and duration change the condition of chiral doped nematic materials from a reflective to a transmissive condition. In this way, the display  35  is actuated to convey useful information.  
         [0034]     The chiral doped nematic liquid crystal materials have the advantage of maintaining a given condition indefinitely after the field is removed. Ambient light striking memory material can be reflected light  70 , providing a “light” image or can become absorbed light  72  which provides a “dark” image. The light modulation is effective in two conditions, which will be described in more detail below. Cholesteric liquid crystal materials can be Merck BL112, BL118 or BL126 which are available from EM Industries of Hawthorne, N.Y. In one experiment, two glass plates were coated with transparent Indium-Tin-Oxide (ITO) to form transparent top conductor  62  and bottom conductor  64 . A laser beam was used to pattern the ITO coatings and 4 micron spacer beads were applied to one of the plates. The two plates were bonded together, with the spacer beads providing a 4 micron gap between the two plates. Black paint was applied to the back of the display over bottom conductor  64  to absorb light passing through memory material  60 . The gap between the plates was filled with E. M. Industries (Hawthorne, N.Y.) chiral nematic fluid BL126 to act as memory material  60 . A 3 millisecond pulse at 100 volts across areas on transparent top conductor  62  and bottom conductor  64  would convert the BL126 memory material  60  to a reflective “bright” areas. A 3 millisecond pulse at 40 volts would clear memory material  60  so that incident light was absorbed by the black paint and create “dark” areas. Such a display can be used to display camera status on memory display  37  for conventional camera  10  or display  54  for electronic camera  12 . The memory display  37  includes the memory material  60  which is selected to be effective in a first condition for changing the state of the memory material  60  to display an image and effective in a second condition for preventing the display of the image. The memory material  60  is selected so that after displaying the image the memory material  60  continues to display the image after the removal of the applied high voltage. As will be seen shortly when a voltage less than the high voltage is applied to the memory material  60 , the memory material  60  is caused to be in its second condition.  
         [0035]      FIG. 4  shows such display  35  having memory material  60 . A reflecting segment  80  has had a 100 volt pulse applied to memory material  60 . A transparent segment  82  has received a 40 volt pulse. Transparent segment  82  passes incident light to a light absorbing surface to create a dark. The individual segments retain a given condition indefinitely after being pulsed. A camera with an electronic flash charging unit provides the source of high voltage. As will be discussed in  FIG. 5 a  camera  10  or  12  with an electronic flash charging unit provides the source of high voltage that can be shut off and the image-bearing medium will continue to have an visible display.  
         [0036]      FIG. 5  is a schematic for driving memory display  37  in conventional camera  10 . Flash capacitor  40  is used as a source of high voltage for pulsing memory display  37 . Flash capacitor  40  stores power at well over 100 volts. Voltage regulator  90  converts a voltage from flash capacitor  40  to either a high or low voltage. In one case, voltage regulator  90  is resistor network that changes 330 volts on flash capacitor  40  to either 100 or 40 volts in response to high-low voltage select line  92  which is used by camera controller  30  to select a pulse voltage for memory display  37 . Using the pre-existing high voltage on flash capacitor  40  eliminates the need for an additional high voltage generating system in conventional camera  10 .  
         [0037]     Camera controller  30  uses high-low voltage select line  92  to changes the voltage applied to memory display  37 . Memory display  37  contains chiral nematic liquid crystal memory material  60  to hold either a reflective or transmissive condition for each segment of memory display  37 .  
         [0038]      FIG. 8A  show the voltage forms applied by camera controller  30  to a segment of memory display  37  to write the segment into the reflective mode. Camera controller  30  sets voltage regulator  90  to a low voltage and pulses all segment switches  94  to clear all the segments with low voltage pulse P L . Voltage regulator  90  is then set to a high voltage, and selected ones of segment drivers  94  are pulsed with a high voltage pulse P H  to convert those segments to the reflective mode.  
         [0039]      FIG. 8B  is a waveform across a segment that has been kept in the transmissive mode. Because P H  was not applied across that segment, the segment remains in a transmissive, dark condition from P L . After the write pulses P L  and P H  are applied, memory display  37  will continue to display status information indefinitely without the use of additional power. Conventional camera  10  can be de-energized and memory display  37  will continue to display information such as the number of images left on film  22  or dates of exposure of frames on film  22  or other information pertinent to images on film  22 . If film camera  10  was a hybrid camera with the capacity to capture electronic images as well as film images, a representation of the at least one image electronically captured could also be displayed on memory display  37  on film cassette  20 .  
         [0040]      FIG. 6A  is a partial top view and  FIG. 6B  is a magnified view of display  35  in electronic capture camera  12 . A substrate  61  supports a plurality of transparent row traces  100 . A second set of transparent traces form column traces  105 . These traces provide for electrical conduction to the display  35  and coupled selectively the high voltage in the flash unit and the low voltage to the display as discussed above. The memory material  60  is disposed between row traces  100  and column traces  105 . Memory material  60  is a chiral nematic material that can be written into either a reflective or transmissive condition. Chiral nematic materials can be tuned to red green and blue wavelengths of reflection and three color planes can be stacked to create a full color display.  
         [0041]      FIG. 7  is a schematic for driving display  54  in an electronic camera  12 . Flash capacitor  40  is used as a source of high voltage for pulses to display  35 . Flash capacitor  40  stores power at well over 100 volts. Voltage regulator  90  converts a voltage from flash capacitor  40  to either a high or low voltage. In one case, voltage regulator  90  is resistor network that changes 330 volts on flash capacitor  40  to either 100 or 40 volts in response to high-low voltage select line  92 . Using the pre-existing high voltage on flash capacitor  40  eliminates the need for a high voltage generating system in electronic camera  12 .  
         [0042]      FIG. 8C  is the drive signals applied across a single color plane of display  35  when used as to display a color, gray scale image stored in removable memory card  52  using the electrical drive of  FIG. 7 . Camera controller  30  selects a first column using column selector  120 . Camera controller  30  sets voltage regulator  90  to a low voltage, and row drivers  115  write a first clearing pulse P L  to all pixels in the row. Camera controller  30  then sets voltage regulator  90  to a high voltage. Row drivers  115  are energized for various gray level times tg. A chiral nematic material changes condition from the transmissive to the reflective condition progressively over time. By selecting an appropriate drive time tg for each pixel  110 , a column of pixels can be written to various degrees of reflection, creating a column of pixels actuated to various gray levels. Camera controller  30  uses to column selector  120  to select the next column of pixels for writing. The process is repeated for each column, and each color plane to create a full-color, gray scale image on display  35 . Other driving schemes can be used such as one proposed by Hashimoto et al, “Reflective Color Display Using Cholesteric Liquid Crystals”, SID 98 Digest, Article 31.1, 1998, pp. 897-900.  
         [0043]      FIG. 9  is a view of a removable memory card  52  with a memory display  54 . Memory card connector  125  mates with the electronic camera  12  to transfer image data for storage as is traditional in electronic cameras. Memory display connector  130  is provided so that the high voltages necessary to update memory display  54  may be applied. One skilled in the art will understand that both the memory card and the memory display can be actuated using a single connector.  
         [0044]     Bar indicator  135  is a display that indicates the remaining storage space on the memory card. Time or date display  140  is an indication of the date of capture of at least one of the images stored on the card. Image display  145  is a representation of at least one image file stored on the card. Image display  145  can be a small image that depicts many image files stored on the card, or could be a portion of one image.  
         [0045]     Battery status indicator  150  shows an indication of camera battery condition. Electronic camera  12  can access the memory display  54  on removable memory card  52  to indicate this and other conditions of the electronic camera  12 . Resolution indicator  155  shows the result of a user selection for resolution and resulting file size. Memory display  54  can be used to this and other selections made by the user.  
         [0046]      FIG. 10  shows a view of a film camera  10  where changeable display  37  is visible through window  160 . Note that display  37  is disposed relative to the removable image bearing medium  20  so that display  37  is removable from camera  10  with removable image bearing medium  20 . For clarity of illustration the display  35  has been omitted.  
         [0047]      FIG. 11  shows a view of electronic camera  12  where changeable display  54  is visible through window  160 . Note that display  54  is disposed relative to the removable image bearing medium  52  so that display  54  is removable from camera  12  with removable image bearing medium  52 . For clarity of illustration the display  35  has been omitted.  
         [0048]     When removable memory card  52  is inserted into electronic camera  12 , communication is initiated by which an indicia of the capabilities of display  54  are communicated to camera  12 . In this way, electronic camera  12  can format signals sent to the display as desired for effective communication to the user. Alternately, if the display is pre-formatted such that certain icons are provided, the communication between electronic camera  12  and removable memory card  52  can establish this fact.  
         [0049]     Upon power-down of camera  12  or upon indication of removal of removable memory card  52 ,electronic camera  12  can change display  54  to indicate only the condition of removable memory card  52  thereby removing all camera status indication prior to removal of the image bearing medium  52 . There is little value in displaying the condition of electronic camera  12  if removable memory card  52  is separated from electronic camera  12 . Mechanical interlocks or warning lights or sounds can be employed to prevent the user from removing card  52  from electronic camera  12  before the pre-removal writing process is complete.  
         [0050]     Display  54  can be integrally secured to the removable memory card  52 . However, it can also be detachable and thus a user can detach it from the removable memory card  52 . This feature permits the display  54  to be reusable on different memory cards and can provide significant cost advantages.  FIG. 12  shows a clip  200  formed on the removable memory card  52  which permits the display  54  to be attached and removed from the removable memory card  52 . An alignment feature  210  facilitates proper location of display  54  on removable memory card  52 . Also, if the separable display  54  is not constructed of a memory material such as chiral doped nematic liquid crystals, it can be necessary to include battery  220  which is electrically connected to display  54 .  
         [0051]     The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.  
       PARTS LIST  
       [0000]    
       
           10  conventional camera  
           12  electronic camera  
           20  film cassette  
           22  film  
           24  take-up spool  
           26  optic  
           30  camera controller  
           35  display  
           37  memory display  
           40  flash capacitor  
           42  flash tube  
           50  sensor  
           52  removable memory card  
           54  memory display  
           60  memory material  
           61  substrate  
           62  transparent top conductor  
           64  bottom conductor  
           70  reflected light  
           72  absorbed light  
           80  reflecting segment  
           82  transmitting segment  
           90  voltage regulator  
           92  high-low voltage select line  
           94  segment switch  
           100  row traces  
           105  column traces 
 
 List Cont&#39;d 
 
           110  pixel  
           115  row drivers  
           120  column selector  
           125  memory card connector  
           130  memory display connector  
           135  bar indicator  
           140  time or date indicator  
           145  image display area  
           150  battery status indicator  
           155  resolution indicator  
           160  window  
           200  clip  
           210  feature  
           220  battery