US 20030117378 A1
An apparatus for capturing and displaying handwritten annotations, for use with a computer system, comprises a transparent digitizing tablet adapted to cooperate with a stylus in order to capture handwritten annotations. It also comprises a transparent electro-luminescent display adapted to display captured handwritten annotations, the transparent digitizing tablet being superposed on the transparent electro-luminescent display.
1. Apparatus for capturing and displaying handwritten annotations, for use with a computer system, the apparatus comprising:
a substantially transparent digitizing tablet responsive to a stylus for capturing handwritten annotations; and
a substantially transparent electro-luminescent display for displaying handwritten annotations captured by the digitizing tablet;
wherein the digitizing tablet is superposed on the electro-luminescent display.
2. The apparatus of
3. A system for capturing and displaying electronic handwritten annotations, comprising:
a substantially transparent digitizing tablet responsive to a stylus for capturing handwritten annotations and a substantially transparent electro-luminescent display for displaying and highlighting handwritten annotations captured by the digitizing tablet, wherein the digitizing tablet is superposed on the electro-luminescent display;
a computer system;
means for digitizing annotations made by the stylus on the digitizing tablet and sending the digitized annotations to the computer system; and
means for transmitting digitized annotations from the computer system to the electro-luminescent display.
4. The system of
5. The system of
 The present invention generally relates to computer interfaces used to input information relating to a physical document. More particularly, the invention relates to a device for capturing and displaying handwritten annotations and a computer system using such a device.
 For most people, handwriting on a physical medium is the most natural manner of recording information. Thus, digitizing tablets are commonly used as input devices for computer systems allowing the entry of handwritten information into a computer. Moreover, in the prior art, several techniques have been described using a transparent digitizing tablet superposed on a display device, such as an LCD screen. Such a device allows an electronic form to be displayed by the LCD screen, through the digitizing tablet, and the strokes or annotations produced by a pencil-like stylus on the digitizing tablet to be displayed on the underlying display device. An example of these techniques is described in U.S. Pat. No. 6,212,297, by Sklarew, entitled “Handwritten keyboardless entry computer system”. Such a device is not adapted to be used with a physical document but only with an electronic document.
 Other types of interfaces make it possible to write with real ink over a physical document, in paper form for example, superposed on a digitizing tablet. This latter is enabled to digitize and capture information handwritten on physical documents. However, such a method degrades the integrity of original physical documents since the document is marked with real ink annotations.
 A main object of the present invention is to overcome the above-mentioned drawbacks and to propose a new apparatus and system adapted to associate additional information with physical documents while keeping intact the integrity of the physical documents.
 In a first aspect, the present invention relates to an apparatus for capturing and displaying handwritten annotations, for use with a computer system, comprising a transparent digitizing tablet adapted to cooperate with a stylus in order to capture handwritten annotations. The apparatus comprises a transparent electro-luminescent display adapted to display captured handwritten annotations, said transparent digitizing tablet being superposed on said transparent electro-luminescent display.
 Thanks to the transparent electro-luminescent display and the transparent digitizing tablet superposed thereon, handwritten annotations can be marked and displayed on a physical document without physically marking the document. Thus, a user can make annotations over a physical document using “electronic ink” so that what is being “written” by the user on the physical document (on the digitizing tablet) can appear to the user electronically illuminated by the transparent electro-luminiscent display, on the same physical document.
 Such an apparatus enables the user to draw, sketch, annotate, construct, outline, enhance, erase, associate and display information directly over physical documents while keeping intact the integrity of said physical documents.
 In a second aspect of the invention, a system for capturing and displaying electronic handwritten annotations comprises:
 an apparatus as described above;
 a computer system;
 a stylus adapted to cooperate with a transparent digitizing tablet of said apparatus;
 said transparent digitizing tablet comprising means for digitizing annotations made by said stylus and means for sending digitized annotations to the computer system;
 said computer system comprising means for transmitting digitized annotations to the transparent electro-luminescent display of said apparatus; and
 said transparent electro-luminescent display comprising means for highlighting said digitized annotations.
 As mentioned above, such a system makes it possible to “write” over physical documents without physically marking said documents.
 According to a preferred embodiment of the invention, the computer system comprises means for storing digitized annotations sent by the transparent digitizing tablet. The handwritten annotations are stored in order to be retrieved and displayed in the future by the same or another user. Moreover, a user can handwrite several pages over a single form without physically marking it, and store said handwritten annotations in a computer system for later use.
 This information can be selectively displayed over the same form. According to a third aspect of the invention, a method for capturing and displaying handwritten annotations, using a system as described above comprises the following steps:
 digitizing annotations made by the stylus on the transparent digitizing tablet;
 sending digitized annotations to the computer system;
 transmitting digitized annotations to the transparent electro-luminescent display; and
 highlighting said digitized annotations.
 According to a fourth aspect of the invention, a method for retrieving and displaying electronic handwritten annotations on a physical document, using a system as described above comprises the following steps:
 identifying a physical document;
 identifying digitized annotations stored in an annotation table associated with the identified document; and
 sending for display the digitized annotations to the transparent electro-luminescent display.
 The invention also includes a computer program comprising computer readable instructions for carrying out the method for capturing and displaying handwritten annotations and/or the method for retrieving and displaying handwritten information according to the invention.
 The method for capturing and displaying handwritten information, the method for retrieving and displaying handwritten information and the computer program present the same advantages and the same characteristics as the apparatus and system which perform them.
 Other features and advantages of the invention will also emerge from the following description.
 In the accompanying drawings, given by way of non-limiting example:
FIG. 1 is a schematic view of an apparatus for capturing and displaying handwritten annotations according to a first aspect of the invention;
FIG. 2 is a block diagram illustrating a system for capturing and displaying handwritten information according to a second aspect of the invention;
FIG. 3 illustrates an algorithm for a method of capturing and displaying handwritten information according to a third aspect of the invention;
 FIGS. 4 to 6 illustrate the method for capturing and displaying handwritten annotations on a physical document;
FIG. 7 illustrates an algorithm for a method of retrieving and displaying handwritten information according to a fourth aspect of the invention; and
FIGS. 8 and 9 illustrate a method for retrieving and displaying handwritten information on a physical document;
 Referring first to FIG. 1, a description will now be given of an apparatus for capturing and displaying handwritten annotations in accordance with the invention.
 This apparatus 10 comprises a transparent digitizing tablet 11 adapted to cooperate with a stylus 12 in order to capture handwritten annotations. Such a transparent digitizing tablet 11 is commonly used to generate signals that are proportional to the coordinates of each point pressed by the stylus 12. Digitizing tablet 11 and stylus 12 can be considered as electronic equivalents of pencil and paper used for writing, drawing, tracing or sketching.
 In a preferred embodiment of the invention, the digitizing tablet may be built from a substrate having a matrix formed by a plurality of first and second lines used to determine the position of the stylus 12 when the latter is applied to the tablet. The first lines correspond to a plurality of scanning lines and the second lines correspond to a plurality of data lines. These first and second lines are made from a transparent conductive material, for example from indium tin oxide (ITO). The application of the stylus to the tablet creates an electric signal, the succession of electric signals corresponding to a drawing on the tablet. An example of transparent digitizing tablets it would be possible to use for implementing the present invention is produced by Wacom Technology Co. and sold under the name Wacom, PL Series, LCD pen tablet system. Such a tablet is used with a pen-like stylus. An example of a stylus it would be possible to use, in combination with the digitizing tablet, is Wacom's wireless, pressure sensitive UltraPen sold by Wacom Technology Co.
 According to the invention, the apparatus further comprises a transparent electro-luminescent display 13 adapted to display captured handwritten annotations. This display 13 is of the type of a transparent organic bright light-emitting device. In a preferred embodiment of the present invention, the display 13 comprises a substrate having an array or a mesh formed by a plurality of first and second lines. The first lines correspond to transparent scanning lines and the second lines correspond to transparent data lines. These first and second lines cross one other and an electro-luminescent element is located at each intersection of the scanning and data lines. Such a light-emitting display, with a passive matrix, may be made of an array of Transparent Organic Light Emitting Devices (TOLED's) which are commonly used to create vision area displays on windshields, cockpits, and so forth. TOLED are today manufactured with standard silicon semiconductors. An example of light emitting foil technology it would be possible to use here is that used for the TOLED's manufactured by UNIVERSAL DISPLAY CO.
 In its basic form, a TOLED is a monolithic, solid-state device consisting in a series of molecules of small size forming organic thin films sandwiched between two transparent, conductive layers. When a voltage is applied across the device, it emits light. This light emission is based upon a luminescence phenomenon wherein electrons and holes are injected and migrate from the contacts toward the organic junction under the applied electric field. When these carriers meet, they form excitons (electron-hole pairs) that recombine radiatively to emit light. As a result, TOLED's are bright and can be directed to emit from either or both surfaces of the sheet. This is possible because, in addition to the transparent contacts, the organic materials are also transparent over their own emission spectrum and throughout most of the visible spectrum. Moreover, TOLED displays can be nearly as clear as glass, since they can be up to 85% transparent when not energized.
 As shown on FIG. 1, the transparent digitizing tablet 11 is superposed on the transparent electro-luminescent display 13. Thus, the apparatus comprises two superposed, functionally independent transparent foils. This apparatus consists in a portable transparent electro-luminescent digitizing tablet 10 which can be superposed on any kind of physical document 5.
 A shown in FIG. 1, the electro-luminescent display 13 is adapted to emit light at the point 1001 that is pressed by the stylus (see the arrow 1002). Since the digitizing tablet superposed thereon is transparent, the light emitted by the display is transmitted through the tablet in order to appear on the top of the apparatus 10. Moreover, since this display is transparent, it is also adapted to transmit light (see the arrow 1003) from the physical document 5 through both the display 13 and the tablet 11, so that the surface of the physical document 5 is visible on unmarked areas. Consequently, such an apparatus is perfectly adapted to write annotations in “electronic ink” and to display these annotations over the document 5, without physically marking the document.
 As shown in FIG. 2, this apparatus 10 is used with a computer system 20. The computer system 20 can be a personal computer, an Internet enabled cell phone, a Personal Digital Assistant, an onboard computer, a network computer, an Internet appliance or a wireless IP enabled device. The apparatus 10 can communicate with the computer system 20 over an infrared link, a serial wired connection or any other communication means. The apparatus 10, the stylus 12 and the computer system 20 thus constitute a system for capturing and displaying electronic handwritten annotations.
 The apparatus 10 comprises means 14 for digitizing annotations made by the stylus 12 and means 15 for sending digitized annotations to the computer system 20. In practice, a pulse driving circuit 16 alternately transmits driving pulses to the X- and Y-axis directions of the digitizing tablet 11 for sensing the current position of the stylus 12. The pulse driving circuit 16 is controlled by the microcontroller 15. The position of the stylus 12 is detected by capacitive coupling sensed in the digitizing tablet 11, that is the stylus 12 senses a position signal in a potential distribution on the digitizing tablet 11 using capacitive coupling, and provides the position to the digitizing means 14 which is referred to as a position sensing circuit 14.
 The position sensing circuit 14 receives the current X- and Y-axis coordinate data of the stylus 12 and converts the coordinate data into digitized position data. The micro-controller 15 transfers data of the position detected from the position sensing circuit 14 to the computer system 20. Thus, the micro-controller 15 is used for sending digitized annotations to the computer system 20.
 Upon reception of position data from the position sensing circuit 14, the micro-controller 15 analyses the position data to calculate the current position of the stylus and updates the computer system 20. This latter comprises means 21 for transmitting digitized annotations to the transparent electro-luminescent display 13 of the apparatus 10. Thus the data of the position of the stylus 12 is directly transmitted by the computer system 20 to an electro-luminescent display driving circuit 17 controlled by the computer system 20. The electro-luminescent display driving circuit provides X-, and Y-axis coordinate driving signals to the electro-luminescent display 13 so that this latter can display the pixel on which is positioned the stylus through the transparent tablet 11.
 The computer system 20 also comprises means 22, 23, 24 for storing digitized annotations sent by the transparent digitizing tablet 11. As described in detail in the following description, in reference to the method performed by the system, the storing means 22, 23, 24 are adapted to store digitized annotations associated with a reference to a physical document which is used in relation with the apparatus 20.
 As illustrated on FIG. 4, the apparatus 10, connected to the computer system 20 is used to create annotations relating to a physical document 5. Here, this document to be annotated is a book of several pages, entitled “Early British Kingdoms”. Any kind of document can be used, and for example, geographic maps, technical plans, commercial catalogs or even any other type of hard-copy, engraved, written or printed surfaces. The physical document 5 could also be a blank paper sheet or a printed form to be filled in. The material of the physical documents can be paper, plastic, wood or any other material.
 As shown on the embodiment of FIG. 3, the method comprises first a step 30 of selecting a physical document and assigning an identification number to it. Here, the identification number is a reference, such as Doc: 170301, which can be written on the document, for example on the first page of the book. A document's annotation table is then created in a creating step 31. As shown on FIG. 5, the annotation table is created on the computer system 20. It comprises the reference number of the document and possibly, other relevant information related to the document such as the title, author, ISBN (International Standard Book Number), date, and so forth.
 In a selecting step 32, a page of the document, here the page 115, is selected and entered in the annotation table. This step corresponds to open a new page entry on the annotation table. An aligning step 33 is then performed wherein the apparatus 10 comprising digitizing tablet 11 and electro-luminescent display 13 in a stack superposed over the selected page of the document. This location of the apparatus is clearly shown in FIG. 5. Since the apparatus comprises superposed sheets that are both transparent, the page of the document underneath the apparatus can be read through the apparatus 10. Preferably, the apparatus 10 is aligned with the borders of the page by some conventional means, for example by adjusting the upper left corner of the page with the upper left corner of the apparatus 10.
 A writing step 34 is then performed by using the stylus 12 as shown in FIG. 6, in order to create annotations relating to the document. Any type of annotations (marks, texts, drawing, underlines, and so forth) can be handwritten by the stylus 12 on the digitizing tablet 11 of the apparatus 10. These annotations made by a user can be directly related to the content of the page seen through the apparatus 10 by virtue of its transparency.
 A digitizing step 35 is adapted to digitize annotations made by the stylus 12 on the transparent digitizing tablet 11. In practice, as illustrated in FIG. 6, the digitizing tablet 11 takes samples, digitizes the sequence Xi, Yi of coordinates of each point pressed by the stylus 12 on the tablet 11 and sends this sequence to the computer system 20. The succession of sequences of coordinates thus constitute a digitizing annotation sent to the computer system 20 during a sending step 36. Under control of the same computer system 20, the sequence of coordinates Xi, Yi are transmitted, i.e. sent back, to the apparatus 10, and more precisely, to the transparent electro-luminescent display 10. This transmitting step 37 is adapted to transmit digitized annotations in order to further highlight the digitized annotations during a displaying step 38.
 In practice, each of the point coordinates Xi, Yi received by the elctro-luminescent display is decoded and the corresponding row and column drivers of the matrix of passive electro-luminescent elements become active. When active, the element (or pixel) located at the intersection of the selected row and column emits light. Obviously, only the electro-luminescent elements corresponding to the stylus strokes sensed by the digitizing tablet 11 must be continuously scanned and refreshed by the computer system 20. Unmarked areas of the apparatus 10 remain transparent, while only the areas marked by the stylus 12 are highlighted in order to display annotations made by the user directly over the selected page of the document, without physically marking this page. Thus, the method described above permits the entering and displaying of annotations simultaneously.
 According to the preferred embodiment described here, the method further comprises a step 39 of storing, in the annotation table stored in the computer system, digitized annotations sent by the apparatus 10.
FIG. 6 shows how the sequence Xi, Yi of point coordinates, corresponding to stylus strokes is stored on the computer system 20, as a “Page Annotation File” (.PAF). that encodes the graphic information of the annotations made by the user. Once created, this .PAF file is referenced in the document's annotation table, associated with the selected document's page.
 In this embodiment, the name of the file to be referenced is composed of the document's reference (here 170301) followed by the page number (here 115).
 As an example, the annotation table associated with a document after annotating different pages (for example pages 3, 12, 57, 115, . . . , 213) would be as follows:
 A method for retrieving and displaying electronic handwritten annotations on a physical document 5 is now described with reference to FIGS. 7 to 9. This retrieving method can be performed by the same user as the one who has made the annotations over the document or by another user from a computer system memorizing the annotation table associated with the document.
 Firstly, the method of retrieving and displaying annotations comprises a step for identifying a physical document. In practice, a first selecting step 70 is adapted to select a physical document by entering a reference number of this document. The user can enter, by means of any interface (keyboard, mouse, etc.) the reference number, here Doc: 170301. As shown in FIG. 8, the apparatus 10 comprises here an array 18 of buttons, preferably touch sensitive, printed on a dedicated touch pad area of the apparatus, directly on the digitizing tablet 11. The user enters the reference of the physical document via a button marked “Doc” and number buttons. When this reference entered in the apparatus is transmitted via the microcontroller 15 to the computer system 20, this latter retrieves the annotation table associated with the selected document.
 Next, a second selecting step 71 is performed to identify a page of the physical document 5, for example the page 115 of the book under consideration. The entering of the number of the page can be made as described above, via the button area 18. The number of the page is transferred from the apparatus 10 to the computer system 20 via the micro-controller 15 and in a retrieving step 72 the computer system identifies the page annotation file (e.g. 170301-115.PAF) of the selected page within the annotation table associated with the selected document. During the selecting step 70 and 71 and the retrieving step 72, the apparatus 10 can be disposed in any way vis-á-vis the physical document.
 An aligning step 73 is then performed for aligning the apparatus 10 over the selected document page. This step is shown in FIG. 9. The upper left corner of the apparatus 10 can be adjusted in a conventional manner with the upper left corner of the page. Thanks to the transparency of the apparatus 10, the user can see the content of the selected document page through the apparatus 10.
 Next, a step 74 of identifying digitized annotations stored in the page annotation file is performed. In fact, in the page annotation file, all the annotations made previously over the page of the document are encoded as graphic information. Next, during a sending step 75, the computer system 10 sends the retrieved annotations to the apparatus 10 for displaying the annotations via the transparent electro-luminescent display 13.
 Consequently, the annotations that have been made by the user or by another user, are displayed by the apparatus 10 directly over the physical document, without marking it. Thus, if two remotely located users share copies of the same document, annotations made by any one user over his copy can be transmitted via a communication network, by sending the annotation table relating to the document, to the other user. This latter can then see the same annotations over his document, through an analogous system shown in FIG. 2. If the physical document is a form to be filled in, this form can be filled in for different persons without physically marking the form. Moreover, it may be noted that, when the physical document is simply a blank sheet of paper, the methods and the system according to the invention can be applied to create a handwritten document or drawing which is memorized in a page annotation file to be displayed again by the user or another user.
 The above-described methods can be performed by microprocessors incorporated respectively in the apparatus 10 and the computer system 20.
 The computer system 20 comprises also a Read Only Memory storing a computer program comprising computer readable instructions for carrying out the method for capturing and displaying handwritten annotations and for retrieving and displaying handwritten annotations.
 The computer system 20 comprises a Random Access Memory adapted to store the modified parameters when the program is run, such as the Page Annotation Files associated with each selected physical document.
 The computer program could also be stored on a hard disk of the computer system 20 or in a movable storage means such as a diskette or a CD-ROM which can be read by a reader incorporated in the computer system 20.
 Persons skilled in the art will recognize that many variations of the teachings of this invention can be practiced that still fall within the claims of the invention which follow.