Abstract:
A method, system, and display apparatus, for securely transmitting and displaying visual data, are disclosed. The method of securely transmitting and displaying the visual data includes encrypting the visual data, transporting encrypted visual data to a display apparatus, decrypting the encrypted visual data within the display apparatus, and displaying the visual data as a visual image. The step of decrypting the visual data includes maintaining an electronic version of the visual data within circuit elements that are substantially inaccessible. The system for securely transmitting and displaying the visual data includes an encryption apparatus, means for transporting the encrypted visual data, and the display apparatus. The display apparatus includes circuit elements that are substantially inaccessible. The circuit elements include a decryption circuit for decrypting the encrypted visual data, which forms the visual data within the display apparatus. The circuit elements also include a display circuit for displaying the visual data as a visual image. The circuit elements are configured such that an electronic version of the visual data is maintained within the circuit elements.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to the field of displaying digital visual information. More particularly, this invention relates to the field of displaying digital visual information in a way that impedes unauthorized copying.  
         BACKGROUND OF THE INVENTION  
         [0002]    A film industry includes exhibitors, distributors, and producers of films. In the film industry, the distributors and the producers are each sometimes referred to as studios. Sometimes, a specific producer of a specific film is also the distributor of the specific film. The exhibitors make arrangements with the distributors or the producers to show the films to audiences in return for a percentage of ticket sales and other considerations. Unauthorized exhibition of the films results in lost revenue for the exhibitors, the distributors, and the producers of the films.  
           [0003]    In the film industry, a master print of a particular film is kept by the studio. The studio copies the master print to produce a working print. The studio copies the working print, at a studio controlled facility, to make release prints. The release prints are distributed to the exhibitors. Each of the release prints costs several thousand dollars to copy, ship, and insure. Each release print is heavy and bulky, which exacerbates shipping costs.  
           [0004]    There are several places where an unauthorized copy of the particular film can be made. An employee at the studio controlled facility can copy the working print to produce the unauthorized copy. A shipping company can lose control of a release print, which is diverted so that the unauthorized copy can be made. An exhibitor employee can make the unauthorized copy. A person can use a video camera at an exhibition to make the unauthorized copy. Once the unauthorized copy is made, a black market enterprise exhibits the particular film or sells video copies of the particular film. The black market enterprise results in lost revenue for the studios and the exhibitors.  
           [0005]    A number of copy protection methods have been proposed to impede making of the unauthorized copy. In a first copy protection method, a watermark is encoded into the working copy or the release print to provide clues to whether the unauthorized copy was made from the working copy or from a specific release print. In a second copy protection method, infrared marks are included in the release print so that the video camera is unable to copy the particular film during the exhibition.  
           [0006]    Recently, interest has developed in electronic cinema, which distributes a film as digital data. A method of the electronic cinema includes converting a film to the digital data, transporting the digital data to an exhibition facility, and displaying the digital data using a digital projector.  
           [0007]    What is needed is a method, system, and display apparatus for the electronic cinema that impedes unauthorized copying of the digital data.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention is a method, system, and display apparatus for securely transmitting and displaying visual data. The method of securely transmitting and displaying the visual data includes encrypting the visual data, transporting encrypted visual data to a display apparatus, decrypting the encrypted visual data within the display apparatus, and displaying the visual data as a visual image. The step of decrypting the visual data includes maintaining an electronic version of the visual data within circuit elements that are substantially inaccessible.  
           [0009]    The system for securely transmitting and displaying the visual data includes an encryption apparatus, means for transporting the encrypted visual data, and the display apparatus. The display apparatus includes circuit elements that are substantially inaccessible. The circuit elements include a decryption circuit for decrypting the encrypted visual data, which forms the visual data within the display apparatus. The circuit elements also include a display circuit for displaying the visual data as a visual image. The circuit elements are configured such that an electronic version of the visual data is maintained within the circuit elements. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 illustrates the preferred electronic cinema system of the present invention.  
         [0011]    [0011]FIG. 2 illustrates the preferred asymmetric key method of the present invention.  
         [0012]    [0012]FIG. 3 illustrates display electronics of the present invention.  
         [0013]    [0013]FIG. 4 illustrates an isometric view of a portion of an alternative Grating Light Valve (GLV) of the present invention.  
         [0014]    [0014]FIG. 5 illustrates a first cross section of the alternative GLV of the present invention in a reflective state.  
         [0015]    [0015]FIG. 6 illustrates the first cross section of the alternative GLV of the present invention in a diffractive state.  
         [0016]    [0016]FIG. 7 illustrates a second cross section of the preferred GLV of the present invention in the reflective state.  
         [0017]    [0017]FIG. 8 illustrates the second cross section of the preferred GLV of the present invention in the diffractive state.  
         [0018]    [0018]FIG. 9 illustrates a display integrated circuit of the present invention.  
         [0019]    [0019]FIG. 10A illustrates a plan view of a display apparatus of the present invention.  
         [0020]    [0020]FIG. 10B illustrates an unfolded elevation view of the display apparatus of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]    The preferred electronic cinema system of the present invention is illustrated in FIG. 1. The preferred electronic cinema system  20  includes an encryption apparatus  22 , a data network  24 , and a display apparatus  26 . Preferably, a master film at a studio is used to produce a master digital reproduction. Alternatively, the master digital reproduction is a direct result of a film production process using electronic generated imagery.  
         [0022]    Preferably, the master digital reproduction is compressed to form a compressed digital reproduction using a lossy compression method. Alternatively, the master digital reproduction is not compressed.  
         [0023]    The compressed digital reproduction is entered to the encryption apparatus  22 , which in turns produces an encrypted digital reproduction. Preferably, the compressed digital reproduction includes visual data and sound data so that the encrypted digital reproduction includes encrypted visual data and encrypted sound data. Alternatively, the compressed digital reproduction only includes the visual data so that the encrypted digital reproduction includes only the encrypted visual data.  
         [0024]    The data network  24  transports the encrypted digital reproduction to the display apparatus  26 . The data network  24  is any type of computer data network suitable for transmitting the encrypted digital reproduction including an optical network, a satellite transmission network, or an internet type network.  
         [0025]    In the electronic cinema system  20 , the encryption apparatus  22  preferably uses a public key to encrypt the compressed digital reproduction in order to produce the encrypted digital reproduction. A public key is part of an asymmetric encryption method. In the asymmetric encryption method, a public key is used to encrypt the compressed digital reproduction and a private key is used to decrypt the encrypted digital reproduction. Thus, the public key is used to encrypt the visual data and the private key is used to decrypt the encrypted visual data.  
         [0026]    The preferred asymmetric key method of the present invention is illustrated in FIG. 2. The preferred asymmetric key method  28  includes a key production step  30 , a public key output step  32 , and a public key input step  31 . The key production step  30  uses an algorithm to produce the public key and the private key. The key production step  30  is well known in the art of encryption. Preferably, the display apparatus  26  performs the key production step  30  and the public key output step  32 . In this way the private key does not leave the display apparatus  26 . Once the public key is available from the public key output step  32 , the public key is input to the encryption apparatus  22 . Preferably, the display apparatus  26  is designed so that the private key is not accessible from outside the display apparatus  26 .  
         [0027]    Display electronics of the present invention are illustrated in FIG. 3. The display electronics  36  includes a decryption integrated circuit  38  and a display integrated circuit  40 . The display electronics  36  form a portion of the display apparatus  26 . The display circuit  40  includes a driver circuit  42  and a Grating Light Valve (GLV)  44 . The decryption circuit  38  is coupled to the driver circuit  42  of the display circuit  40 . The driver circuit  42  is coupled to the GLV  44 .  
         [0028]    Preferably, the decryption integrated circuit  38  and the display integrated circuit  40  are separate integrated circuits. In operation, the decryption integrated circuit  38  receives the encrypted digital reproduction and decrypts the encrypted digital reproduction using the private key. Thus, the decryption circuit  38  decrypts the encrypted visual data forming the visual data within the decryption integrated circuit  38 .  
         [0029]    In order to pass the visual data from the decryption integrated circuit  38  to the display integrated circuit  40 , the decryption integrated circuit  38  encodes the visual data forming encoded visual data. The decryption integrated circuit transfers the encoded visual data to the driver circuit  42  of the display integrated circuit  40 . The driver circuit  42  decodes the encoded visual data within the display integrated circuit  40 . The encoded visual data is encrypted such that the visual data is not available as in-the-clear data within the display apparatus  26 . Thus, a zealous technician will be unable to easily access an electronic form of the visual data within the display apparatus  26 .  
         [0030]    An alternative GLV of the present invention is disclosed in U.S. Pat. No. 5,311,360, which is hereby incorporated by reference. A portion of the alternative GLV is illustrated in FIG. 4. The alternative GLV  45  includes first ribbons  46  and a base  48 . The first ribbons  46  are suspended in tension over the base  48 .  
         [0031]    A reflective state for the alternative GLV  45  is illustrated in FIG. 5. The first ribbons  46  include first reflective metallic coatings  50 . The base  48  includes second reflective metallic coatings  52 . In the reflective state, the first reflective metallic coatings  50  are located at a half wavelength λ/2 above the second reflective metallic coatings  52 . Incident light I reflects from the first and second reflective coatings,  50  and  52 , to form reflected light R. Since the first and second reflective coatings,  50  and  52 , are separated by the half wavelength λ/2, a first phase shift for the incident light I reflecting from the first and second reflective metallic coatings,  50  and  52 , is a full wavelength λ and thus the reflected light R is formed.  
         [0032]    A diffractive state for the alternative GLV  45  is illustrated in FIG. 6. An electrostatic potential is developed between the first reflective metallic coatings  50  and the base  48 , which deflects the first ribbons  46  to the base  48 . In the diffractive state, the first reflective metallic coatings  50  are located at a quarter wavelength λ/4 above the second reflective metallic coatings  52 . The incident light I reflects from the first and second reflective metallic coatings,  50  and  52 , to form the diffractive state including plus and minus one diffraction orders, D +1  and D −1 . Since the first and second reflective metallic coatings,  50  and  52 , are separated by the quarter wavelength λ/4, a second phase shift for the incident light I reflecting from the first and second reflective metallic coatings,  50  and  52 , is the half wavelength λ/2 and thus the diffractive state is formed.  
         [0033]    The preferred GLV  44  of the present invention as well as a method of making the preferred GLV is disclosed in U.S. application Ser. No. 09/104,159, which is hereby incorporated by reference.  
         [0034]    The reflective state for the preferred GLV  44  is illustrated in FIG. 7. The preferred GLV  44  includes the first ribbons  46 , second ribbons  54 , and the base  48 . The first ribbons  46  include the first reflective metallic coatings  50 . The second ribbons  54  includes the second reflective metallic coatings  52 . In the reflective state, the first and second ribbons,  46  and  54 , are suspended in tension at the same height above the base  48 . The incident light I reflects from the first and second reflective metallic coatings,  50  and  52 , to form the reflected light R. Since the first and second reflective metallic coatings,  50  and  52 , are at the same height, a third phase shift for the incident light I reflecting from the first and second reflective metallic coatings is zero and thus the reflected light R is formed.  
         [0035]    The diffractive state for the preferred GLV of the present invention is illustrated in FIG. 8. In the diffractive state, the electrostatic potential is developed between the first reflective coatings  50  and the base  48 , which deflects the first ribbons  46  towards the base  48 . The second ribbons  54  remain suspended in the tension above the base  48 . In the diffractive state, a height difference between the first and second reflective metallic coatings,  50  and  52 , is the quarter wavelength λ/4. The incident light I reflects from the first and second reflective coatings,  50  and  52 , to form the diffractive state including the plus and minus one diffraction orders, D +1  and D −1 . Since the first and second reflective metallic coatings,  50  and  52 , are separated by the quarter wavelength λ/4, a third phase shift for the incident light is the half wavelength λ/2 and thus the diffractive state is formed.  
         [0036]    In both the preferred GLV  44  and the alternative GLV  45 , a pixel of a visual image is formed from a grouping of the first and second reflective metallic coatings,  50  and  52 . Preferably, the pixel of the visual image is formed by three pairs of the first and second reflective metallic coatings,  50  and  52 . In both the preferred GLV  44  and the alternative GLV  45 , the first and second reflective metallic coatings,  50  and  52 , are preferably aluminum.  
         [0037]    It will be readily apparent to one skilled in the art that the quarter, half, and full wavelengths, λ/4, λ/2, and λ, of FIGS. 6, 7, and  9 , are optical path lengths. Thus, adjusting an angle of incidence from normal to into or out-of the page will result in physical dimensions that are less than the quarter, half, and full wavelengths, λ/4, λ/2, and λ.  
         [0038]    The display integrated circuit  40  of the present invention is illustrated in FIG. 9. The display integrated circuit  40  includes the driver circuit  42  and the preferred GLV  44 . Preferably, the preferred GLV  44  includes one thousand eighty pixels  56 . The one thousand eighty pixels  56  forms a vertical dimension of the visual image. The driver circuit  42  is illustrated on a front surface of the display integrated circuit. Alternatively, the driver circuit  42  is on a back surface opposite the front surface or is situated in an intermediary region between the front and back surfaces. The driver circuit is fabricated using known semiconductor processing techniques for fabricating integrated circuits. Since the driver circuit  42  and the preferred GLV  44  are integrated on the display integrated circuit, human access to the electronic version of the visual data within the display integrated circuit is not feasible.  
         [0039]    A plan view of the display apparatus  26  of the present invention is illustrated in FIG. 10A. The plan view also includes a viewing screen  58 . The display apparatus  26  includes the decryption integrated circuit  38  and an optical system  60 . The optical system  60  includes red, green and blue lasers,  62 R,  62 G, and  62 B, a compound lens  64 , the display integrated circuit  40 , an eyepiece type lens  66 , a stop  68 , a projection lens  70 , and a scanning mirror assembly  72 . The optical system  60  is arranged along an optic axis  74 . Note that as illustrated in FIG. 10A, an angle  76  for the optic axis  74  at the display integrated circuit  40  is a right angle. The angle  76  is for illustration purposes and is preferably much less than the right angle.  
         [0040]    An unfolded elevation view of the optical system  60  of the display apparatus  26  and the viewing screen  58  is illustrated in FIG. 10B. The optical system  60  has been unfolded along the optic axis  74  for illustration purposes. Also, the red, green, and blue lasers,  62 R,  62 G, and  62 B, are illustrated as a single laser  62 .  
         [0041]    In operation, the red, green, and blue lasers,  62 R,  62 G, and  62 B, are sequentially activated in order to sequentially illuminate the GLV  44 . Light from the red, green, and blue lasers,  62 R,  62 B, and  62 G, are combined by a dichroic prism block  77 . The compound lens  64  forms wedge focused light  79  that illuminates the GLV  44 . The GLV  44  forms the reflected light R or the plus and minus one diffraction orders, D +1  and D −1 , for each of the one thousand eighty pixels  56 . The eyepiece type lens  66  focuses the reflected light R and the plus and minus one diffraction orders, D +1  and D −1 . The stop  68  stops the reflected light R. The stop  68  allows the plus and minus one diffraction orders, D +1  and D −1 , to pass the stop  68 . The projection lens  70 , via a scanning mirror  78  of the scanning mirror assembly  72 , projects the one thousand eighty pixels  56  onto the viewing screen  58 . The scanning mirror  78  is rotated in a first scan motion A by a scanning motor  80 .  
         [0042]    The decryption integrated circuit  38  receives the encrypted visual data and decrypts the encrypted visual data thus forming the visual data within the decryption integrated circuit  38 . The decryption integrated circuit  38  encodes the visual data thus forming the encoded visual data. The decryption integrated circuit  38  transmits the encoded visual data to the driver circuit  42  of the display integrated circuit  40 . The driver circuit  42  decodes the encoded visual data within the display integrated circuit  40  thus forming the visual data within the display integrated circuit  40 .  
         [0043]    The driver circuit  42  is coupled to the preferred GLV  44 , the red, green, and blue lasers,  62 R,  62 G, and  62 B, and the scanning mirror assembly  72 . The one thousand eighty pixels  56  of the GLV are driven by the driver circuit  40  in order to form a linear image, which is projected onto the viewing screen  58 . Thus, the one thousand eighty pixels  56  are projected onto the viewing screen  58 , which forms the linear image on the viewing screen  58 .  
         [0044]    The linear image is formed by the red, green, and blue lasers,  62 R,  62 G, and  62 B, being activated sequentially, which is referred to as a line sequential color. The linear image is formed by a red linear image of red pixels, a green linear image of green pixels, and a blue linear image of blue pixels projected on the viewing screen  58  using the line sequential color. Thus, the red, green, and blue pixels form color pixels and the color pixels form the linear image. The red, green, and blue linear images are projected onto the viewing screen  58  within a short time period so that a viewer viewing the visual image cannot detect the line sequential color. The line sequential color is repeatedly scanned over the viewing screen  58 , with a second scan motion B, in order to form the visual image.  
         [0045]    Frame formats that are likely to be used in electronic cinema applications include an Academy frame format and a CinemaScope frame format. For the Academy frame format, approximately 2,000 linear images are formed on the viewing screen  58 . For the CinemaScope frame format, approximately 2,540 linear images are formed on the viewing screen  58 . So for the Academy frame format, the visual image is formed by approximately a 2,000 by 1,080 of the color pixels. For the CinemaScope frame format, the visual image is formed by approximately a 2,540 by 1,080 of the color pixels.  
         [0046]    It will be readily apparent to one skilled in the art that other arrays of the color pixels, with a different frame width or a different frame height, can form the visual image.  
         [0047]    By appropriately choosing a speed for the first scan motion A, the scan motion B will be such that a video camera will be unable to record the visual image, which adds an additional level of security to the present invention.  
         [0048]    In a first alternative electronic cinema system, the data network  24  is replaced by a storage media, which is physically carried from the encryption apparatus  22  to the display apparatus  26 . The storage media is selected from a group including a magnetic tape, a magnetic disk, an optical disk, and a programmable memory device. The storage media is either a standard storage media or a non-standard storage media. The non-standard storage media is specifically designed to be compatible only with the display apparatus  26 .  
         [0049]    In a second alternative electronic cinema system, the asymmetric encryption method is replaced with a symmetric encryption method. The symmetric encryption method uses a secret key to encrypt the visual data. The symmetric encryption method uses the secret key to decrypt the encrypted visual data.  
         [0050]    A first alternative asymmetric key method of the present invention includes the key production step  30  of the preferred asymmetric key method plus a private key output step, and private key input step. In the private key input step, the private key is input to the display apparatus  26  in a way that preferably precludes human access to the private key. Preferably, the first alternative asymmetric key method  28  and the private key input step are performed at a manufacturing facility for the display apparatus  26 . In this way, the private key is input directly to the display apparatus  26  without human access. Alternatively, the private key input step includes placing the private key on a private key storage media. The private key is stored on the private key storage media in such a way that the private key can only be accessed once. Thus, the private key storage media is connected to the display apparatus  26  and the private key is transferred to the display apparatus  26  while the private key is erased from the private key storage media.  
         [0051]    In first alternative display electronics, the decryption integrated circuit  38  and the display integrated circuit  40  are integrated circuit elements of a single integrated circuit. In the first alternative display apparatus, the decryption apparatus  38  does not encode the visual data nor does the driver integrated circuit  40  decode the encoded visual data. Since the decryption integrated circuit  38  and the display integrated circuit  40  are the integrated circuit elements of the single integrated circuit, the visual data can pass freely between the decryption integrated circuit  38  and the display integrated circuit  40  without providing the in-the-clear data.  
         [0052]    A first alternative display apparatus of the present invention comprises an alternative optical system. The alternative optical system includes the red, green, and blue lasers,  62 R,  62 G, and  62 B, first, second, and third compound optics, first, second, and third display integrated circuits, combining optics, the eyepiece type lens  66 , the stop  68 , the projection lens  70 , and the scanning mirror assembly  72 . In operation, the first alternative display apparatus illuminates the display screen  58 .  
         [0053]    In the first alternative display apparatus, the first display integrated circuit includes a red GLV, the second display integrated circuit includes a green GLV, and the third display integrated circuit includes a blue GLV. In operation, the red, green, and blue GLV&#39;s produce red, green, and blue linear images, respectively, which combine to form a color linear image. Thus, the first alternative display apparatus provides separate red, green, and blue channels, which combine simultaneously to illuminate the display screen  58 .  
         [0054]    In a second alternative display apparatus, a turning mirror arrangement is used to illuminate the GLV  44 . Details of using the turning mirror are disclosed in related U.S. Pat. No. 5,982,553, entitled, “Display Device Incorporating One-Dimensional Grating Light Valve Array,” and U.S. Pat. No. 5,629,801, entitled, “Diffraction Grating Light Doubling Collection System,” which are incorporated in their entirety by reference.  
         [0055]    In a third alternative display apparatus, the red, green, and blue lasers,  62 R,  62 G, and  62 B, are replaced with red, green, and blue light emitting diodes or other red, green, and blue light sources.  
         [0056]    In a fourth alternative display apparatus, the red, green, and blue lasers,  62 R,  62 B, and  62 G, are replaced by a monochrome light source so that a monochrome image is formed on the viewing screen.  
         [0057]    It will be readily apparent to one skilled in the art that, while this description is directed towards electronic cinema, the method, system, and display apparatus of the present invention are appropriate for providing a securely transmitted and displayed visual image in applications such as cable television, direct satellite television, securely broadcast television, video telephone, etc.  
         [0058]    It will be readily apparent to one skilled in the art that other various modifications may be made to the preferred embodiment without departing from the spirit and scope of the invention as defined by the appended claims.